1
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Dare T, Baker PA, Anderson SM. Paediatric emergency front-of-neck airway: issues of ethics, law, and philosophy. Br J Anaesth 2024; 132:631-634. [PMID: 38245452 DOI: 10.1016/j.bja.2023.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/17/2023] [Accepted: 12/18/2023] [Indexed: 01/22/2024] Open
Abstract
Practitioners can face significant challenges when managing the airways of infants and neonates because of their unique anatomical and physiological features. The requirement for emergency airway management in this age group is rare. Details of emergency airway techniques in paediatric practice guidelines are missing or lack consensus, and it is known that outcomes for affected children can be poor. Ideally, these children should be managed by experienced paediatric airway practitioners working in a team. However, situations can arise where practitioners, unfamiliar and inexperienced with infants, find themselves in charge. So, what happens when such a practitioner encounters this life-or-death scenario and feels ill-equipped to act? The ethical and legal issues surrounding the management of this emergency are clearly defined, but they can be unknown or misunderstood by doctors. Compounding the extreme stress of the scenario is the moral and ethical dilemma of whether to act or not. The following discussion explores these issues and examines the philosophical and psychological perspectives.
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Affiliation(s)
- Tim Dare
- Department of Philosophy and Faculty of Law, University of Auckland, Auckland, New Zealand
| | - Paul A Baker
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.
| | - Sarah M Anderson
- Department of Psychological Medicine, University of Auckland, Auckland, New Zealand
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2
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Iwan S, Sutton W, Baker PA, Sereika R, Vohra YK. Synthesis and Thermal Oxidation Resistance of Boron-Rich Boron-Carbide Material. Materials (Basel) 2023; 16:6526. [PMID: 37834663 PMCID: PMC10573354 DOI: 10.3390/ma16196526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 09/29/2023] [Accepted: 09/29/2023] [Indexed: 10/15/2023]
Abstract
A boron-rich boron-carbide material (B4+δC) was synthesized by spark plasma sintering of a ball-milled mixture of high-purity boron powder and graphitic carbon at a pressure of 7 MPa and a temperature of 1930 °C. This high-pressure, high-temperature synthesized material was recovered and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, Vickers hardness measurements, and thermal oxidation studies. The X-ray diffraction studies revealed a single-phase rhombohedral structure (space group R-3m) with lattice parameters in hexagonal representation as a = 5.609 ± 0.007 Å and c = 12.082 ± 0.02 Å. The experimental lattice parameters result in a value of δ = 0.55, or the composition of the synthesized compound as B4.55C. The high-resolution scans of boron binding energy reveal the existence of a B-C bond at 188.5 eV. Raman spectroscopy reveals the existence of a 386 cm-1 vibrational mode representative of C-B-B linear chain formation due to excess boron in the lattice. The measured Vickers microhardness at a load of 200 gf shows a high hardness value of 33.8 ± 2.3 GPa. Thermal gravimetric studies on B4.55C were conducted at a temperature of 1300 °C in a compressed dry air environment, and its behavior is compared to other high-temperature ceramic materials such as high-entropy transition metal boride. The high neutron absorption cross section, high melting point, high mechanical strength, and thermal oxidation resistance make this material ideal for applications in extreme environments.
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Affiliation(s)
- Seth Iwan
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Wesley Sutton
- Department of Chemistry, Physics, and Astronomy, Georgia College and State University, Milledgeville, GA 31061, USA
| | - Paul A Baker
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Raimundas Sereika
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Yogesh K Vohra
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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3
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Chrimes N, Higgs A, Hagberg CA, Baker PA, Cooper RM, Greif R, Kovacs G, Law JA, Marshall SD, Myatra SN, O'Sullivan EP, Rosenblatt WH, Ross CH, Sakles JC, Sorbello M, Cook TM. Preventing unrecognised oesophageal intubation: a consensus guideline from the Project for Universal Management of Airways and international airway societies. Anaesthesia 2022; 77:1395-1415. [PMID: 35977431 DOI: 10.1111/anae.15817] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2022] [Indexed: 01/07/2023]
Abstract
Across multiple disciplines undertaking airway management globally, preventable episodes of unrecognised oesophageal intubation result in profound hypoxaemia, brain injury and death. These events occur in the hands of both inexperienced and experienced practitioners. Current evidence shows that unrecognised oesophageal intubation occurs sufficiently frequently to be a major concern and to merit a co-ordinated approach to address it. Harm from unrecognised oesophageal intubation is avoidable through reducing the rate of oesophageal intubation, combined with prompt detection and immediate action when it occurs. The detection of 'sustained exhaled carbon dioxide' using waveform capnography is the mainstay for excluding oesophageal placement of an intended tracheal tube. Tube removal should be the default response when sustained exhaled carbon dioxide cannot be detected. If default tube removal is considered dangerous, urgent exclusion of oesophageal intubation using valid alternative techniques is indicated, in parallel with evaluation of other causes of inability to detect carbon dioxide. The tube should be removed if timely restoration of sustained exhaled carbon dioxide cannot be achieved. In addition to technical interventions, strategies are required to address cognitive biases and the deterioration of individual and team performance in stressful situations, to which all practitioners are vulnerable. These guidelines provide recommendations for preventing unrecognised oesophageal intubation that are relevant to all airway practitioners independent of geography, clinical location, discipline or patient type.
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Affiliation(s)
- N Chrimes
- Department of Anaesthesia, Monash Medical Centre, Melbourne, Australia
| | - A Higgs
- Department of Anaesthesia and Intensive Care, Warrington Teaching Hospitals NHS Foundation Trust, Cheshire, UK
| | - C A Hagberg
- Department of Anaesthesiology and Peri-operative Medicine, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - P A Baker
- Department of Anaesthesiology, University of Auckland, New Zealand.,Department of Anaesthesiology, Starship Children's Hospital, Auckland, New Zealand
| | - R M Cooper
- Department of Anesthesiology and Pain Medicine, University of Toronto, ON, Canada
| | - R Greif
- Department of Anesthesiology and Pain Medicine, Bern University Hospital, University of Bern, Switzerland.,Department of Medical Education, Sigmund Freud University, Vienna, Austria
| | - G Kovacs
- Departments of Emergency Medicine, Anesthesia, Medical Neurosciences and Division of Medical Education, Dalhousie University, Halifax, Canada
| | - J A Law
- Department of Anesthesia, Pain Management and Peri-operative Medicine, Dalhousie University, Halifax, Canada
| | - S D Marshall
- Department of Critical Care, University of Melbourne, VIC, Australia.,Department of Anaesthesia and Peri-operative Medicine, Monash University, Melbourne, VIC, Australia
| | - S N Myatra
- Department of Anaesthesiology, Critical Care and Pain, Tata Memorial Hospital, Homi Bhabha National Institute, Mumbai, India
| | - E P O'Sullivan
- Department of Anaesthesiology, St James's Hospital, Dublin, Ireland
| | - W H Rosenblatt
- Department of Anesthesia, Yale School of Medicine, New Haven, CT, USA
| | - C H Ross
- Department of Emergency Medicine, Mercy Health, Javon Bea Hospital, Rockton and Riverside Campuses, Rockford, IL, USA.,Department of Surgery, University of Illinois College of Medicine, Chicago, IL, USA
| | - J C Sakles
- Department of Emergency Medicine, University of Arizona College of Medicine, Tucson, AZ, USA
| | - M Sorbello
- Anesthesia and Intensive Care, AOU Policlinico San Marco University Hospital, Catania, Italy
| | - T M Cook
- Department of Anaesthesia and Intensive Care Medicine, Royal United Hospitals Bath NHS Foundation Trust, Bath, UK.,School of Medicine, University of Bristol, Bristol, UK
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4
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Baker PA, O'Sullivan EP, Aziz MF. Unrecognised oesophageal intubation: time for action. Br J Anaesth 2022; 129:836-840. [PMID: 36192220 DOI: 10.1016/j.bja.2022.08.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/25/2022] [Accepted: 08/30/2022] [Indexed: 11/02/2022] Open
Abstract
Patients worldwide die every year from unrecognised oesophageal intubation, which is an avoidable complication of airway management usually resulting from human error. Unrecognised oesophageal intubation can occur in any patient of any age whenever intubation occurs regardless of the seniority or experience of the airway practitioner or others involved in the patient's airway management. The tragic fact is that it continues to happen despite improvements in monitoring, airway devices, and medical education. We review these improvements with strategies to eliminate this problem.
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Affiliation(s)
- Paul A Baker
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand; Department of Paediatric Anaesthesia, Starship Children's Hospital, Auckland, New Zealand.
| | - Ellen P O'Sullivan
- Department of Anaesthesia and Intensive Care Medicine, St James's Hospital, Dublin, Ireland
| | - Michael F Aziz
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
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5
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Endlich Y, Hore PJ, Baker PA, Beckmann LA, Bradley WP, Chan KLE, Chapman GA, Jephcott CGA, Kruger PS, Newton A, Roessler P. Updated guideline on equipment to manage difficult airways: Australian and New Zealand College of Anaesthetists. Anaesth Intensive Care 2022; 50:430-446. [PMID: 35722809 DOI: 10.1177/0310057x221082664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Australian and New Zealand College of Anaesthetists (ANZCA) recently reviewed and updated the guideline on equipment to manage a difficult airway. An ANZCA-established document development group, which included representatives from the Australasian College for Emergency Medicine and the College of Intensive Care Medicine of Australia and New Zealand, performed the review, which is based on expert consensus, an extensive literature review, and bi-nationwide consultation. The guideline (PG56(A) 2021, https://www.anzca.edu.au/getattachment/02fe1a4c-14f0-4ad1-8337-c281d26bfa17/PS56-Guideline-on-equipment-to-manage-difficult-airways) is accompanied by a detailed background paper (PG56(A)BP 2021, https://www.anzca.edu.au/getattachment/9ef4cd97-2f02-47fe-a63a-9f74fa7c68ac/PG56(A)BP-Guideline-on-equipment-to-manage-difficult-airways-Background-Paper), from which the current recommendations are reproduced on behalf of, and with the permission of, ANZCA. The updated 2021 guideline replaces the 2012 version and aims to provide an updated, objective, informed, transparent, and evidence-based review of equipment to manage difficult airways.
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Affiliation(s)
- Yasmin Endlich
- Department of Anaesthesia and Acute Pain Medicine, Royal Adelaide Hospital, Adelaide, Australia.,Department of Paediatric Anaesthesia, Women's and Children's Hospital, North Adelaide, Australia.,Faculty of Anaesthesia, University of Adelaide, Adelaide, Australia
| | - Phillipa J Hore
- Department of Anaesthesia and Acute Pain Medicine, St Vincent's Hospital, Melbourne, Australia
| | - Paul A Baker
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.,Department of Anaesthesia, Starship Children's Hospital, Auckland, New Zealand
| | - Linda A Beckmann
- Department of Anaesthesia and Acute Pain Medicine, Royal Brisbane and Women's Hospital, Herston, Australia
| | - William P Bradley
- Department of Anaesthesia and Perioperative Medicine, The Alfred, Melbourne, Australia.,Faculty of Anaesthesia, Monash University, Melbourne, Australia
| | - Kah L E Chan
- Department of Anaesthesia and Acute Pain Medicine, Royal Brisbane and Women's Hospital, Herston, Australia
| | - Gordon A Chapman
- Department of Anaesthesia, Royal Perth Hospital, Perth, Australia.,Faculty of Anaesthesia, University of Western Australia, Perth, Australia
| | | | - Peter S Kruger
- Department of Intensive Care Medicine, Princess Alexandra Hospital, Brisbane, Australia
| | - Alastair Newton
- Department of Emergency Medicine, The Prince Charles Hospital, Brisbane, Australia.,Retrieval Services Queensland, Brisbane, Australia
| | - Peter Roessler
- Safety and Advocacy Unit, Australian and New Zealand College of Anaesthetists, Melbourne, Australia
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Baker PA, von Ungern-Sternberg BS. Primum non nocere ("first do no harm") with oxygen therapy. Paediatr Anaesth 2022; 32:101-102. [PMID: 35045214 DOI: 10.1111/pan.14367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/02/2021] [Accepted: 12/05/2021] [Indexed: 11/30/2022]
Affiliation(s)
- Paul A Baker
- Department of Anesthesiology, University of Auckland, Auckland, New Zealand.,Starship Children's Hospital, Auckland, New Zealand
| | - Britta S von Ungern-Sternberg
- Division of Emergency Medicine, Anesthesia and Pain Medicine, Medical School, The University of Western Australia, Perth, WA, Australia.,Department of Anesthesia and Pain Management, Perth Children's Hospital, Perth, WA, Australia.,Perioperative Medicine Team, Telethon Kid's Institute, Perth, WA, Australia
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Abstract
ABSTRACT Worcester, KS, Baker, PA, and Bollinger, LM. Effects of inertial load on sagittal plane kinematics of the lower extremity during flywheel-based squats. J Strength Cond Res 36(1): 63-69, 2022-Increasing load increases flexion of lower extremity joints during weighted squats; however, the effects of inertial load on lower extremity kinematics during flywheel-based resistance training (FRT) squats remain unclear. The purpose of this study was to evaluate sagittal plane kinematics of lower extremity joints during FRT squats at various inertial loads. Nine recreationally resistance-trained subjects (3M, 6F) completed a bout of FRT squats with inertial loads of 0.050, 0.075, and 0.100 kg·m2. Two-dimensional sagittal plane kinematics were monitored with retroreflective markers at a rate of 60 Hz. Joint angles and angular velocities of the knee, trunk + hip, trunk inclination, and ankle were quantified throughout concentric and eccentric actions. Effects of inertial load were determined by repeated-measures analysis of variance with α = 0.05. Average power and average vertical velocity decreased with increasing inertial load, whereas average force increased. Minimal and maximal sagittal plane joint angles of the knee, trunk + hip, trunk inclination, and ankle were not significantly different among inertial loads. However, peak joint angular velocities of the knee and trunk + hip tended to decrease with increasing inertial load. Conversely trunk inclination and ankle dorsiflexion velocities were not significantly different among inertial loads. Increasing inertial load from 0.050 to 0.100 kg·m2 significantly reduces average power during FRT squats primarily by decreasing movement velocity, which seems to be specific to the knee and hip joints. It is possible that lower concentric energy input at high inertial loads prevents increased joint flexion during FRT squats.
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Affiliation(s)
- Katherine S Worcester
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky; and
| | - Paul A Baker
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky; and
| | - Lance M Bollinger
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky; and
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
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Wong DJN, El-Boghdadly K, Owen R, Johnstone C, Neuman MD, Andruszkiewicz P, Baker PA, Biccard BM, Bryson GL, Chan MTV, Cheng MH, Chin KJ, Coburn M, Jonsson Fagerlund M, Lobo CA, Martinez-Hurtado E, Myatra SN, Myles PS, Navarro G, O'Sullivan E, Pasin L, Quintero K, Shallik N, Shamim F, van Klei WA, Ahmad I. Emergency Airway Management in Patients with COVID-19: A Prospective International Multicenter Cohort Study. Anesthesiology 2021; 135:292-303. [PMID: 33848324 PMCID: PMC8274456 DOI: 10.1097/aln.0000000000003791] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Background: Tracheal intubation for patients with COVID-19 is required for invasive mechanical ventilation. The authors sought to describe practice for emergency intubation, estimate success rates and complications, and determine variation in practice and outcomes between high-income and low- and middle-income countries. The authors hypothesized that successful emergency airway management in patients with COVID-19 is associated with geographical and procedural factors. Methods: The authors performed a prospective observational cohort study between March 23, 2020, and October 24, 2020, which included 4,476 episodes of emergency tracheal intubation performed by 1,722 clinicians from 607 institutions across 32 countries in patients with suspected or confirmed COVID-19 requiring mechanical ventilation. The authors investigated associations between intubation and operator characteristics, and the primary outcome of first-attempt success. Results: Successful first-attempt tracheal intubation was achieved in 4,017/4,476 (89.7%) episodes, while 23 of 4,476 (0.5%) episodes required four or more attempts. Ten emergency surgical airways were reported—an approximate incidence of 1 in 450 (10 of 4,476). Failed intubation (defined as emergency surgical airway, four or more attempts, or a supraglottic airway as the final device) occurred in approximately 1 of 120 episodes (36 of 4,476). Successful first attempt was more likely during rapid sequence induction versus non–rapid sequence induction (adjusted odds ratio, 1.89 [95% CI, 1.49 to 2.39]; P < 0.001), when operators used powered air-purifying respirators versus nonpowered respirators (adjusted odds ratio, 1.60 [95% CI, 1.16 to 2.20]; P=0.006), and when performed by operators with more COVID-19 intubations recorded (adjusted odds ratio, 1.03 for each additional previous intubation [95% CI, 1.01 to 1.06]; P=0.015). Intubations performed in low- or middle-income countries were less likely to be successful at first attempt than in high-income countries (adjusted odds ratio, 0.57 [95% CI, 0.41 to 0.79]; P=0.001). Conclusions: The authors report rates of failed tracheal intubation and emergency surgical airway in patients with COVID-19 requiring emergency airway management, and identified factors associated with increased success. Risks of tracheal intubation failure and success should be considered when managing COVID-19. The authors report a secondary analysis of associations of intubation and operator characteristics related to the primary outcome of first-attempt intubation success in 4,476 intubations among 1,722 clinicians at 607 institutions across 32 countries, also considering differential rates of success between high-income and low- and middle-income countries. Although successful first-attempt intubation was noted in 89.7% of intubations, 0.5% required four or more attempts, an emergency surgical airway was required in 0.2%, and a composite variable of failed intubation occurred in 0.8%. Multivariable analysis demonstrated that successful first attempts were more likely with rapid sequence intubations, when operators used powered air-purifying respirators, and with increasing operator experience. Intubations performed in low- and middle-income countries were nearly half as likely to be successful on first attempt than in high-income countries. These results provide potentially useful information for global and local policy-making related to this and future pandemics. However, the observational nature, along with lack of patient level characteristics, leave room for substantial residual confounding of these associations. Supplemental Digital Content is available in the text.
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9
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Cumin D, Baker PA, Anderson BJ. Incidence of post-induction hypoxemia in children and the effect of induction gas composition. Paediatr Anaesth 2021; 31:763-769. [PMID: 33615619 DOI: 10.1111/pan.14161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 02/11/2021] [Accepted: 02/13/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Pediatric preoxygenation and inhalation induction of anesthesia can include a mixture of gases. In children, the clinical impact on oxygenation while using other gases with oxygen during an inhalation induction is unknown. AIM We aimed to determine the impact of oxygen, nitrous oxide, and air concentrations added to the volatile agent by recording the incidence of hypoxemia following an inhalation gaseous induction in children. METHOD Records from an Automated Information Management System were used to find the incidence of hypoxemia following an inhalation induction of anesthesia. Episodes of hypoxemia (SaO2 < 90% sustained for at least 120 s) were recorded in the 10 min after the 3-min induction period. Nitrous oxide and oxygen concentrations were recorded and nitrogen concentration was deduced. We also considered patient sex, age, and ASA status as covariates. RESULTS A total of 27 258 cases were included in the analysis. The overall incidence of hypoxemia following an inhalation induction of anesthesia was 5.08% (95% CI 4.83 5.35). Hypoxemia was more common in younger patients and those with higher ASA scores. Controlling for those factors and sex, the incidence of hypoxemia increased 1.2-fold when inspired oxygen concentration was less than 60% and hypoxemia was 2.37 times greater than the overall incidence when the inspired oxygen concentration was less than 40%. There was no clear effect of different concentrations of nitrous oxide or nitrogen when those were factored into the model. CONCLUSION The risk of hypoxemia following an inhalation induction of anesthesia in children is minimized when the inspired concentration of oxygen is greater than 60%.
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Affiliation(s)
- David Cumin
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
| | - Paul A Baker
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.,Department of Paediatric Anaesthesia, Starship Children's Hospital, Auckland, New Zealand
| | - Brian J Anderson
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.,Department of Paediatric Anaesthesia, Starship Children's Hospital, Auckland, New Zealand
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10
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Mann CM, Baker PA, Sainsbury DM, Taylor R. A comparison of cannula insufflation device performance for emergency front of neck airway. Paediatr Anaesth 2021; 31:482-490. [PMID: 33432628 DOI: 10.1111/pan.14128] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 12/29/2020] [Accepted: 01/05/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Pediatric emergency front of neck airway guidelines recommend oxygenation via cannula cricothyroidotomy or tracheotomy. AIM The primary aim was to measure test lung pressures and volumes generated by cannula insufflation devices recommended for emergency front of neck airway compared with a pressure limit of 50 cm H2 O and volume limit of 20 ml/kg. The secondary aim was to calculate pressure and volume variability. The primary end point was test lung expansion. METHOD Adult, child, and infant airway models, each with three degrees of upper airway obstruction, were oxygenated using six cannula insufflation devices: 3-way stopcock, Rapid-O2 , Manujet, Enk oxygen flow modulator, Ventrain, and self-inflating bags. Test lung pressures and volumes were recorded. RESULTS Pressures and volumes from all devices were highly variable, despite oxygen flow calibration and strict adherence to oxygen insufflation protocols. With upper airway occlusion, pressures >50 cm H2 0 were produced by Rapid-O2 and Enk oxygen flow meter in adult and infant lungs, 3-way stopcock in adult and child lungs, and Manujet in all lung sizes. Ventrain produced acceptable pressures <35 cm H2 O in all models. Test lung volumes >20 ml/kg were recorded in airway models with fully obstructed proximal airways using Rapid-O2 and Enk oxygen flow meter in infant lungs, and Manujet in all lung sizes. Rapid-O2 produced lung volumes >20 ml/kg in the infant model with partially obstructed and open upper airways. Test lung volumes >20 ml/kg were produced by the 3-way stopcock in adult, child, and infant models. Insufflation was unsuccessful with the self-inflating bag. Ventrain produced acceptable volumes <7 ml/kg in all airway models. CONCLUSION Rapid-O2 , Enkoxygen flow meter, Manujet, and 3-way stopcock oxygenation devices produced highly variable and excessive airway pressures and volumes in models with obstructed upper airways. Self-inflating bag insufflation was unsuccessful. Ventrain was the only device that insufflated oxygen with acceptable pressures and volumes in adult, child, and infant airway models with any degree of airway obstruction.
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Affiliation(s)
- Caroline M Mann
- Department of Paediatric Anaesthesia, Starship Children's Hospital, Auckland, New Zealand
| | - Paul A Baker
- Department of Paediatric Anaesthesia, Starship Children's Hospital, Auckland, New Zealand
| | - David M Sainsbury
- Department of Paediatric Anaesthesia, Starship Children's Hospital, Auckland, New Zealand
| | - Richard Taylor
- Department of Otorhinolaryngology and Cardiac Anaesthesia, Auckland City Hospital, Auckland, New Zealand
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11
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Foley LJ, Urdaneta F, Berkow L, Aziz MF, Baker PA, Jagannathan N, Rosenblatt W, Straker TM, Wong DT, Hagberg CA. Difficult Airway Management in Adult COVID-19 Patients: Statement by the Society of Airway Management. Anesth Analg 2021; 133:876-890. [PMID: 33711004 DOI: 10.1213/ane.0000000000005554] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The COVID-19 disease, caused by Coronavirus SARS-CoV-2, often results in severe hypoxemia requiring airway management. Because SARS CoV-2 virus is spread via respiratory droplets, bag-mask ventilation, intubation, and extubation may place health care workers (HCW) at risk. While existing recommendations address airway management in patients with COVID-19, no guidance exists specifically for difficult airway management. Some strategies normally recommended for difficult airway management may not be ideal in the setting of COVID-19 infection. To address this issue the Society for Airway Management (SAM) created a task force to review existing literature and current Practice Guidelines for management of the difficult airway by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. SAM task force created recommendations for management of known or suspected difficult airway in the setting of known or suspected COVID-19 infection. The goal of the task force was to optimize successful airway management while minimizing exposure risk. Each member conducted a literature review on specific clinical practice section utilizing standard search engines (PubMed, Ovid, Google Scholar). Existing recommendations and evidence for difficult airway management in COVID-19 context were developed. Each specific recommendation was discussed among task force members and modified until unanimously approved by all task force members. Elements of AGREE Reporting Checklist for dissemination of clinical practice guidelines were utilized to develop this statement. Airway management in the COVID-19 patient increases HCW exposure risk. and difficult airway management often takes longer, may involve multiple procedures with aerosolization potential, strict adherence to personal protective equipment (PPE) protocols is mandatory to reduce risk to providers. When patient's airway risk assessment suggests awake tracheal intubation is an appropriate choice of technique, procedures that may cause increased aerosolization of secretions should be avoided. Optimal preoxygenation before induction with tight seal facemask may be performed to reduce risk of hypoxemia. Unless the patient is experiencing oxygen desaturation, positive pressure bag-mask ventilation after induction may be avoided to reduce aerosolization. For optimal intubating conditions, patients should be anesthetized with full muscle relaxation. Videolaryngoscopy is recommended as first-line strategy for airway management. If emergent invasive airway access is indicated, we recommend a surgical technique such as scalpel-bougie-tube, rather than an aerosolizing generating procedure, such as transtracheal jet ventilation. This statement represents recommendations by SAM task force for the difficult airway management of adults with COVID-19 with the goal to optimize successful airway management while minimizing the risk of clinician exposure.
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Affiliation(s)
- Lorraine J Foley
- Department of Anesthesiology, Winchester Hospital of Beth Israel Lahey Health, Tufts School of Medicine, Boston, MA, USA
| | - Felipe Urdaneta
- Department of Anesthesiology, University of Florida NFSGVHS, Gainesville FL, USA
| | - Lauren Berkow
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Michael F Aziz
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Paul A Baker
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
| | - Narasimhan Jagannathan
- Department of Anesthesiology Ann & Robert H. Lurie Children's Hospital of Chicago/Northwestern University Feinberg School of Medicine Chicago, IL
| | - William Rosenblatt
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, USA
| | - Tracey M Straker
- Department of Anesthesiology, Montefiore Hospital, Albert Einstein College of Medicine New York, NY, USA
| | - David T Wong
- Department of Anesthesia, Toronto Western Hospital, University of Toronto, Toronto, Canada
| | - Carin A Hagberg
- Department of Anesthesiology & Perioperative Medicine, University of Texas MD Anderson Cancer Center, Houston, TX, USA
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Wei H, Jiang B, Behringer EC, Hofmeyr R, Myatra SN, Wong DT, Sullivan EPO, Hagberg CA, McGuire B, Baker PA, Li J, Pylypenko M, Ma W, Zuo M, Senturk NM, Klein U. Controversies in airway management of COVID-19 patients: updated information and international expert consensus recommendations. Br J Anaesth 2020; 126:361-366. [PMID: 33256990 PMCID: PMC7836532 DOI: 10.1016/j.bja.2020.10.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 10/28/2020] [Accepted: 10/30/2020] [Indexed: 12/14/2022] Open
Affiliation(s)
- Huafeng Wei
- Department of Anaesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA.
| | - Bailin Jiang
- Department of Anaesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA; Department of Anaesthesiology, Peking University People's Hospital, Beijing, China
| | - Elizabeth C Behringer
- Division of Cardiovascular Surgery & Critical Care, Kaiser Permanente Los Angeles Medical Center, Los Angeles, CA, USA
| | - Ross Hofmeyr
- Department of Anaesthesia & Perioperative Medicine, University of Cape Town, Groote Schuur Hospital, Cape Town, South Africa
| | - Sheila N Myatra
- Department of Anesthesiology, Critical Care and Pain, Tata Memorial Hospital, Homi Bhabha National Institute, Mumbai, India
| | - David T Wong
- Department of Anesthesia, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Ellen P O' Sullivan
- Department of Anaesthesia and Intensive Care Medicine, St James's Hospital, Dublin, Ireland
| | - Carin A Hagberg
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Barry McGuire
- Department of Anaesthesia, Ninewells Hospital, Dundee, UK
| | - Paul A Baker
- Department of Anaesthesia, Starship Children's Health, Auckland, New Zealand
| | - Jane Li
- Department of Anaesthesia and Pain Management, Central Coast Local Health District, NSW, Australia
| | - Maksym Pylypenko
- Department of Anesthesiology and Intensive Care, Shupyk National Medical Academy of Postgraduate Education, Kiev, Ukraine
| | - Wuhua Ma
- Department of Anesthesiology, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Mingzhang Zuo
- Department of Anaesthesiology, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Science, Beijing, China
| | - Nuzhet M Senturk
- Istanbul Universitesi, Istanbul Tıp Fakültesi, Anesteziyoloji AD, Istanbul, Turkey
| | - Uwe Klein
- Südharz-Klinikum Nordhausen, Nordhausen, Germany
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13
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Bollinger LM, Brantley JT, Tarlton JK, Baker PA, Seay RF, Abel MG. Construct Validity, Test-Retest Reliability, and Repeatability of Performance Variables Using a Flywheel Resistance Training Device. J Strength Cond Res 2020; 34:3149-3156. [PMID: 33105365 DOI: 10.1519/jsc.0000000000002647] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Bollinger, LM, Brantley, JT, Tarlton, JK, Baker, PA, Seay, RF, and Abel, MG. Construct validity, test-retest reliability, and repeatability of performance variables using a flywheel resistance training device. J Strength Cond Res 34(11): 3149-3156, 2020-Power production is highly associated with physical performance; however, the ability to quantitatively measure power output during resistance exercise is lacking. The purpose of this study was to determine the validity and test-retest reliability of flywheel-based performance testing. Twelve young, resistance trained subjects completed 2 bouts of resistance exercise using a flywheel resistance training device (Exxentric kbox 4 Pro). Each session consisted of 3 sets of 3 exercise (bent-over row, Romanian deadlift, and biceps curl) with varying moments of inertia (0.050, 0.075, and 0.100 kg·m, respectively) in random order. Each set consisted of 5 maximal effort repetitions with 3-minute recovery between sets. Average power, peak concentric and eccentric power, average force, average speed, and total work for each set were recorded. Regression analysis revealed a near-perfect relationship between measured and predicted power, force, and work at given workloads. Pearson's r between trials 1 and 2 revealed good (≥0.70) to excellent (≥0.90) test-retest reliability for all outcomes with the exception of peak eccentric power for biceps curls (r = 0.69), which narrowly missed the cutoff for acceptable reliability. Bland-Altman plots revealed small (approximately 5-15%), but statistically significant bias between the 2 trials for some measures. Coefficient of repeatability for all outcomes was relatively high, indicating poor repeatability. Flywheel-based performance testing provides valid data. However, reliability varies between individual lifts and specific outcomes. Given the poor repeatability between trials, it is likely that subjects who are unaccustomed to this modality may require multiple testing sessions or a thorough familiarization period to ensure accurate measures of power, force, speed, and work during flywheel-based performance testing.
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Affiliation(s)
- Lance M Bollinger
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky
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14
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Chakrabarty K, Chen WC, Baker PA, Vijayan VM, Chen CC, Catledge SA. Superhard Boron-Rich Boron Carbide with Controlled Degree of Crystallinity. Materials (Basel) 2020; 13:ma13163622. [PMID: 32824358 PMCID: PMC7475823 DOI: 10.3390/ma13163622] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/11/2020] [Accepted: 08/13/2020] [Indexed: 11/25/2022]
Abstract
Superhard boron-rich boron carbide coatings were deposited on silicon substrates by microwave plasma chemical vapor deposition (MPCVD) under controlled conditions, which led to either a disordered or crystalline structure, as measured by X-ray diffraction. The control of either disordered or crystalline structures was achieved solely by the choice of the sample being placed either directly on top of the sample holder or within an inset of the sample holder, respectively. The carbon content in the B-C bonded disordered and crystalline coatings was 6.1 at.% and 4.5 at.%, respectively, as measured by X-ray photoelectron spectroscopy. X-ray diffraction analysis of the crystalline coating provided a good match with a B50C2-type structure in which two carbon atoms replaced boron in the α-tetragonal B52 structure, or in which the carbon atoms occupied different interstitial sites. Density functional theory predictions were used to evaluate the dynamical stability of the potential B50C2 structural forms and were consistent with the measurements. The measured nanoindentation hardness of the coatings was as high as 64 GPa, well above the 40 GPa threshold for superhardness.
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15
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El-Boghdadly K, Wong DJN, Owen R, Neuman MD, Pocock S, Carlisle JB, Johnstone C, Andruszkiewicz P, Baker PA, Biccard BM, Bryson GL, Chan MTV, Cheng MH, Chin KJ, Coburn M, Jonsson Fagerlund M, Myatra SN, Myles PS, O'Sullivan E, Pasin L, Shamim F, van Klei WA, Ahmad I. Risks to healthcare workers following tracheal intubation of patients with COVID-19: a prospective international multicentre cohort study. Anaesthesia 2020; 75:1437-1447. [PMID: 32516833 PMCID: PMC7300828 DOI: 10.1111/anae.15170] [Citation(s) in RCA: 182] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2020] [Indexed: 01/25/2023]
Abstract
Healthcare workers involved in aerosol‐generating procedures, such as tracheal intubation, may be at elevated risk of acquiring COVID‐19. However, the magnitude of this risk is unknown. We conducted a prospective international multicentre cohort study recruiting healthcare workers participating in tracheal intubation of patients with suspected or confirmed COVID‐19. Information on tracheal intubation episodes, personal protective equipment use and subsequent provider health status was collected via self‐reporting. The primary endpoint was the incidence of laboratory‐confirmed COVID‐19 diagnosis or new symptoms requiring self‐isolation or hospitalisation after a tracheal intubation episode. Cox regression analysis examined associations between the primary endpoint and healthcare worker characteristics, procedure‐related factors and personal protective equipment use. Between 23 March and 2 June 2020, 1718 healthcare workers from 503 hospitals in 17 countries reported 5148 tracheal intubation episodes. The overall incidence of the primary endpoint was 10.7% over a median (IQR [range]) follow‐up of 32 (18–48 [0–116]) days. The cumulative incidence within 7, 14 and 21 days of the first tracheal intubation episode was 3.6%, 6.1% and 8.5%, respectively. The risk of the primary endpoint varied by country and was higher in women, but was not associated with other factors. Around 1 in 10 healthcare workers involved in tracheal intubation of patients with suspected or confirmed COVID‐19 subsequently reported a COVID‐19 outcome. This has human resource implications for institutional capacity to deliver essential healthcare services, and wider societal implications for COVID‐19 transmission.
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Affiliation(s)
- K El-Boghdadly
- Department of Anaesthesia and Perioperative Medicine, Guy's and St Thomas' NHS Foundation Trust, London, UK.,King's College London, UK
| | - D J N Wong
- Department of Anaesthesia and Perioperative Medicine, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - R Owen
- Medical Statistics, London School of Hygiene and Tropical Medicine, London, UK
| | - M D Neuman
- Penn Centre for Peri-operative Outcomes Research and Transformation, University of Pennsylvania, USA
| | - S Pocock
- Medical Statistics, London School of Hygiene and Tropical Medicine, London, UK
| | - J B Carlisle
- Department of Anaesthesia, Peri-operative Medicine and Intensive Care, Torbay Hospital, UK
| | - C Johnstone
- Department of Anaesthesia and Perioperative Medicine, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - P Andruszkiewicz
- Department of Anaesthesiology and Intensive Care, Institute of Tuberculosis and Lung Diseases, Poland
| | | | - B M Biccard
- Department of Anaesthesia and Perioperative Medicine, University of Cape Town, South Africa
| | - G L Bryson
- Department of Anaesthesia and Pain Medicine, University of Ottawa, Canada
| | - M T V Chan
- The Chinese University of Hong Kong, Hong Kong
| | - M H Cheng
- Division of Anaesthesiology, Singapore General Hospital, Singapore
| | - K J Chin
- Department of Anaesthesia and Pain Medicine, University of Toronto, Canada
| | - M Coburn
- Department of Anaesthesia, University Hospital RWTH, Aachen, Germany
| | - M Jonsson Fagerlund
- Perioperative Medicine and Intensive Care, Karolinska University Hospital, Sweden
| | - S N Myatra
- Department of Anaesthesiology, Critical Care and Pain, Tata Memorial Hospital, India
| | - P S Myles
- Department of Anaesthesiology and Perioperative Medicine, Monash University, Australia
| | | | - L Pasin
- Department of Anaesthesia and Intensive Care, Azienda Ospedale-Università di Padova, Italy
| | - F Shamim
- Department of Anaesthesiology, Aga Khan University Hospital, Pakistan
| | - W A van Klei
- Division Anaesthesia, Intensive Care and Emergency Medicine, University Medical Center Utrecht, Netherlands
| | - I Ahmad
- Department of Anaesthesia and Perioperative Medicine, Guy's and St Thomas' NHS Foundation Trust, London, UK.,King's College London, UK
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16
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Affiliation(s)
- Paul A. Baker
- Department of AnesthesiologyUniversity of AucklandAucklandNew Zealand,Starship Children’s HospitalAucklandNew Zealand
| | - James Peyton
- Department of AnesthesiologyCritical Care, and Pain MedicineBoston Children’s HospitalHarvard School of MedicineBostonMAUSA
| | - Britta S. von Ungern‐Sternberg
- Division of Emergency Medicine, Anesthesia and Pain MedicineMedical SchoolThe University of Western AustraliaPerthWAAustralia,Department of Anesthesia and Pain ManagementPerth Children's HospitalPerthWAAustralia,Perioperative Medicine TeamTelethon Kid's InstitutePerthWAAustralia
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17
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Baker PA, von Ungern-Sternberg BS, Engelhardt T. Desperate times breed desperate measures: About valiance or foolhardiness. Paediatr Anaesth 2020; 30:634-635. [PMID: 33210423 DOI: 10.1111/pan.13883] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 04/13/2020] [Indexed: 11/26/2022]
Affiliation(s)
- Paul A Baker
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.,Starship Children's Hospital, Auckland, New Zealand
| | - Britta S von Ungern-Sternberg
- Division of Emergency Medicine, Anaesthesia and Pain Medicine, Medical School, The University of Western Australia, Perth, WA, Australia.,Department of Anaesthesia and Pain Management, Perth Children's Hospital, Perth, WA, Australia.,Perioperative Medicine Team, Telethon Kid's Institute, Perth, WA, Australia
| | - Thomas Engelhardt
- Department of Anesthesia, McGill University Health Center, Montreal Children's Hospital, Montreal, QC, Canada
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18
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McNarry AF, M Cook T, Baker PA, O'Sullivan EP. The Airway Lead: opportunities to improve institutional and personal preparedness for airway management. Br J Anaesth 2020; 125:e22-e24. [PMID: 32386835 PMCID: PMC7183994 DOI: 10.1016/j.bja.2020.04.053] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 12/20/2022] Open
Affiliation(s)
| | | | - Paul A Baker
- Starship Children's Hospital, Auckland, New Zealand
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19
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Baker PA, Chen WC, Chen CC, Catledge SA, Vohra YK. First-Principles Predictions and Synthesis of B 50C 2 by Chemical Vapor Deposition. Sci Rep 2020; 10:4454. [PMID: 32157150 PMCID: PMC7064583 DOI: 10.1038/s41598-020-61462-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 02/27/2020] [Indexed: 11/09/2022] Open
Abstract
Density functional theory predictions have been combined with the microwave-plasma chemical vapor deposition technique to explore metastable synthesis of boron-rich boron-carbide materials. A thin film synthesis of high-hardness (up to 37 GPa) B50C2 via chemical vapor deposition was achieved. Characterization of the experimental crystal structure matches well with a new theoretical model structure, with carbon atoms inserted into the boron icosahedra and 2b sites in a α-tetragonal B52 base structure. Previously reported metallic B50C2 structures with carbons inserted only into the 2b or 4c sites are found to be dynamically unstable. The newly predicted structure is insulating and dynamically stable, with a computed hardness value and electrical properties in excellent agreement with the experiment. The present study thus validates the density functional theory calculations of stable crystal structures in boron-rich boron-carbide system and provides a pathway for large-area synthesis of novel materials by the chemical vapor deposition method.
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Affiliation(s)
- Paul A Baker
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama, 35294, USA
| | - Wei-Chih Chen
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama, 35294, USA
| | - Cheng-Chien Chen
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama, 35294, USA
| | - Shane A Catledge
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama, 35294, USA
| | - Yogesh K Vohra
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama, 35294, USA.
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20
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Affiliation(s)
- Paul A Baker
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.,Department of Paediatric Anaesthesia, Starship Children's Hospital, Auckland, New Zealand
| | - Robert T Greif
- Department of Anaesthesiology and Pain Therapy, Bern University Hospital, University of Bern, Bern, Switzerland.,Medical Education, Sigmund Freud University Vienna, Vienna, Austria
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21
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Vijayan VM, Tucker BS, Baker PA, Vohra YK, Thomas V. Non-equilibrium hybrid organic plasma processing for superhydrophobic PTFE surface towards potential bio-interface applications. Colloids Surf B Biointerfaces 2019; 183:110463. [PMID: 31493629 DOI: 10.1016/j.colsurfb.2019.110463] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 08/02/2019] [Accepted: 08/26/2019] [Indexed: 01/02/2023]
Abstract
Superhydrophobic surfaces have gained increased attention due to the high water-repellency and self-cleaning capabilities of these surfaces. In the present study, we explored a novel hybrid method of fabricating superhydrophobic poly(tetrafluoroethylene) (PTFE) surfaces by combining the physical etching capability of oxygen plasma with the plasma-induced polymerization of a organic monomer methyl methacrylate (MMA). This novel hybrid combination of oxygen-MMA plasma has resulted in the generation of superhydrophobic PTFE surfaces with contact angle of 154°. We hypothesized that the generation of superhydrophobicity may be attributed to the generation of fluorinated poly(methyl methacrylate) (PMMA) moieties formed by the combined effects of physical etching causing de-fluorination of PTFE and the subsequent plasma polymerization of MMA. The plasma treated PTFE surfaces were then systematically characterized via XPS, FTIR, XRD, DSC and SEM analyses. The results have clearly shown a synergistic effect of the oxygen/MMA combination in comparison with either the oxygen plasma alone or MMA vapors alone. Furthermore, the reported new hybrid combination of Oxygen-MMA plasma has been demonstrated to achieve superhydrophobicity at lower power and short time scales than previously reported methods in the literature. Hence the reported novel hybrid strategy of fabricating superhydrophobic PTFE surfaces could have futuristic potential towards biointerface applications.
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Affiliation(s)
- Vineeth M Vijayan
- Center for Nanoscale Materials and Biointergration, College of Arts and Sciences, University of Alabama at Birmingham, 1300 University Blvd. CH 386 Birmingham, AL 35294, United States; Polymers & Healthcare Materials/ Devices, Department of Material Science and Engineering, University of Alabama at Birmingham, 1150 10th Avenue SouthBirmingham, AL 35294, United States
| | - Bernabe S Tucker
- Polymers & Healthcare Materials/ Devices, Department of Material Science and Engineering, University of Alabama at Birmingham, 1150 10th Avenue SouthBirmingham, AL 35294, United States
| | - Paul A Baker
- Center for Nanoscale Materials and Biointergration, College of Arts and Sciences, University of Alabama at Birmingham, 1300 University Blvd. CH 386 Birmingham, AL 35294, United States
| | - Yogesh K Vohra
- Center for Nanoscale Materials and Biointergration, College of Arts and Sciences, University of Alabama at Birmingham, 1300 University Blvd. CH 386 Birmingham, AL 35294, United States
| | - Vinoy Thomas
- Center for Nanoscale Materials and Biointergration, College of Arts and Sciences, University of Alabama at Birmingham, 1300 University Blvd. CH 386 Birmingham, AL 35294, United States; Polymers & Healthcare Materials/ Devices, Department of Material Science and Engineering, University of Alabama at Birmingham, 1150 10th Avenue SouthBirmingham, AL 35294, United States.
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22
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Baker PA, Rankin L. Successful Application of Optiflow THRIVE to Restore Oxygenation and Facilitate Retrieval of an Aspirated Nut in a Severely Hypoxic Child: A Case Report. A A Pract 2019; 13:130-132. [PMID: 30985322 DOI: 10.1213/xaa.0000000000001012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In this case, the novel use of high-flow nasal oxygen successfully treated severe hypoxia by delivering oxygen through a very narrow space between the bronchoscope and the tracheal wall. Removal of a foreign body from a child's lung can be associated with hypoxia and cardiorespiratory arrest. The shared airway of the bronchoscope must allow surgical instrumentation and oxygenation. This simultaneous use can compromise gas exchange, leading to hypoxia. In this case, high-flow nasal oxygen supplemented bronchoscope oxygenation to treat a severely hypoxic child and facilitate subsequent removal of a peanut without further incident.
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Affiliation(s)
- Paul A Baker
- From the Department of Paediatric Anaesthesia, Starship Children's Hospital, Auckland, New Zealand.,Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
| | - Lorna Rankin
- From the Department of Paediatric Anaesthesia, Starship Children's Hospital, Auckland, New Zealand
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23
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Guédron S, Tolu J, Brisset E, Sabatier P, Perrot V, Bouchet S, Develle AL, Bindler R, Cossa D, Fritz SC, Baker PA. Late Holocene volcanic and anthropogenic mercury deposition in the western Central Andes (Lake Chungará, Chile). Sci Total Environ 2019; 662:903-914. [PMID: 30708305 DOI: 10.1016/j.scitotenv.2019.01.294] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/22/2019] [Accepted: 01/22/2019] [Indexed: 06/09/2023]
Abstract
Volcanism is one of the major natural processes emitting mercury (Hg) to the atmosphere, representing a significant component of the global Hg budget. The importance of volcanic eruptions for local-scale Hg deposition was investigated using analyses of Hg, inorganic elemental tracers, and organic biomarkers in a sediment sequence from Lake Chungará (4520 m a.s.l.). Environmental change and Hg deposition in the immediate vicinity of the Parinacota volcano were reconstructed over the last 2700 years, encompassing the pre-anthropogenic and anthropogenic periods. Twenty eruptions delivering large amounts of Hg (1 to 457 μg Hg m-2 yr-1 deposited at the timescale of the event) were locally recorded. Peaks of Hg concentration recorded after most of the eruptions were attributed to a decrease in sedimentation rate together with the rapid re-oxidation of gaseous elemental Hg and deposition with fine particles and incorporation into lake primary producers. Over the study period, the contribution of volcanic emissions has been estimated as 32% of the total Hg input to the lake. Sharp depletions in primary production occurred at each eruption, likely resulting from massive volcaniclastic inputs and changes in the lake-water physico-chemistry. Excluding the volcanic deposition periods, Hg accumulation rates rose from natural background values (1.9 ± 0.5 μg m-2 yr-1) by a factor of 2.3 during the pre-colonial mining period (1400-900 yr cal. BP), and by a factor of 6 and 7.6, respectively, during the Hispanic colonial epoch (400-150 yr cal. BP) and the industrial era (~140 yr cal. BP to present). Altogether, the dataset indicates that lake primary production has been the main, but not limiting, carrier for Hg to the sediment. Volcanic activity and climate change are only secondary drivers of local Hg deposition relative to the magnitude of regional and global anthropogenic emissions.
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Affiliation(s)
- S Guédron
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, 38000 Grenoble, France; Laboratorio de Hidroquímica, Instituto de Investigaciones Químicas, Universidad Mayor de San Andres, Campus Universitario de Cota Cota, casilla 3161, La Paz, Bolivia.
| | - J Tolu
- Department of Ecology and Environmental Science, Umeå University, Sweden; Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland and ETH Zürich, Universitätstrasse 16, CH-8092 Zürich, Switzerland
| | - E Brisset
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, 38000 Grenoble, France; IPHES, Institut Català de Paleoecologia Humana i Evolució Social, Tarragona, Spain; Àrea de Prehistòria, Universitat Rovira i Virgili, Tarragona, Spain
| | - P Sabatier
- Environnement, Dynamique et Territoires de Montagne (EDYTEM), Université Savoie Mont Blanc, CNRS, 73373 Le Bourget du Lac, France
| | - V Perrot
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, 38000 Grenoble, France
| | - S Bouchet
- LCABIE - Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, IPREM UMR 5254, CNRS et Université de Pau et des Pays de l'Adour, Hélioparc, F-64053 Pau, France; Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland and ETH Zürich, Universitätstrasse 16, CH-8092 Zürich, Switzerland
| | - A L Develle
- Environnement, Dynamique et Territoires de Montagne (EDYTEM), Université Savoie Mont Blanc, CNRS, 73373 Le Bourget du Lac, France
| | - R Bindler
- Department of Ecology and Environmental Science, Umeå University, Sweden
| | - D Cossa
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, 38000 Grenoble, France
| | - S C Fritz
- Department of Earth and Atmospheric Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - P A Baker
- Division of Earth and Ocean Sciences, Duke University, Durham, NC, USA
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24
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Baker PA, Catledge SA, Harris SB, Ham KJ, Chen WC, Chen CC, Vohra YK. Computational Predictions and Microwave Plasma Synthesis of Superhard Boron-Carbon Materials. Materials (Basel) 2018; 11:ma11081279. [PMID: 30044407 PMCID: PMC6117701 DOI: 10.3390/ma11081279] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 07/18/2018] [Accepted: 07/23/2018] [Indexed: 01/14/2023]
Abstract
Superhard boron-carbon materials are of prime interest due to their non-oxidizing properties at high temperatures compared to diamond-based materials and their non-reactivity with ferrous metals under extreme conditions. In this work, evolutionary algorithms combined with density functional theory have been utilized to predict stable structures and properties for the boron-carbon system, including the elusive superhard BC5 compound. We report on the microwave plasma chemical vapor deposition on a silicon substrate of a series of composite materials containing amorphous boron-doped graphitic carbon, boron-doped diamond, and a cubic hard-phase with a boron-content as high as 7.7 at%. The nanoindentation hardness of these composite materials can be tailored from 8 GPa to as high as 62 GPa depending on the growth conditions. These materials have been characterized by electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction, and nanoindentation hardness, and the experimental results are compared with theoretical predictions. Our studies show that a significant amount of boron up to 7.7 at% can be accommodated in the cubic phase of diamond and its phonon modes and mechanical properties can be accurately modeled by theory. This cubic hard-phase can be incorporated into amorphous boron-carbon matrices to yield superhard materials with tunable hardness values.
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Affiliation(s)
- Paul A Baker
- Department of Physics, University of Alabama at Birmingham (UAB), Birmingham, AL 35294, USA.
| | - Shane A Catledge
- Department of Physics, University of Alabama at Birmingham (UAB), Birmingham, AL 35294, USA.
| | - Sumner B Harris
- Department of Physics, University of Alabama at Birmingham (UAB), Birmingham, AL 35294, USA.
| | - Kathryn J Ham
- Department of Physics, University of Alabama at Birmingham (UAB), Birmingham, AL 35294, USA.
| | - Wei-Chih Chen
- Department of Physics, University of Alabama at Birmingham (UAB), Birmingham, AL 35294, USA.
| | - Cheng-Chien Chen
- Department of Physics, University of Alabama at Birmingham (UAB), Birmingham, AL 35294, USA.
| | - Yogesh K Vohra
- Department of Physics, University of Alabama at Birmingham (UAB), Birmingham, AL 35294, USA.
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Baker PA, Goodloe DR, Vohra YK. Morphological Transition in Diamond Thin-Films Induced by Boron in a Microwave Plasma Deposition Process. Materials (Basel) 2017; 10:ma10111305. [PMID: 29135942 PMCID: PMC5706252 DOI: 10.3390/ma10111305] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Revised: 11/10/2017] [Accepted: 11/12/2017] [Indexed: 12/01/2022]
Abstract
The purpose of this study is to understand the basic mechanisms responsible for the synthesis of nanostructured diamond films in a microwave plasma chemical vapor deposition (MPCVD) process and to identify plasma chemistry suitable for controlling the morphology and electrical properties of deposited films. The nanostructured diamond films were synthesized by MPCVD on Ti-6Al-4V alloy substrates using H2/CH4/N2 precursor gases and the plasma chemistry was monitored by the optical emission spectroscopy (OES). The synthesized thin-films were characterized by x-ray diffraction and scanning electron microscopy. The addition of B2H6 to the feedgas during MPCVD of diamond thin-films changes the crystal grain size from nanometer to micron scale. Nanostructured diamond films grown with H2/CH4/N2 gases demonstrate a broad (111) Bragg x-ray diffraction peak (Full-Width at Half-Maximum (FWHM) = 0.93° 2θ), indicating a small grain size, whereas scans show a definite sharpening of the diamond (111) peak (FWHM = 0.30° 2θ) with the addition of boron. OES showed a decrease in CN (carbon–nitrogen) radical in the plasma with B2H6 addition to the gas mixture. Our study indicates that CN radical plays a critical role in the synthesis of nanostructured diamond films and suppression of CN radical by boron-addition in the plasma causes a morphological transition to microcrystalline diamond.
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Affiliation(s)
- Paul A Baker
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - David R Goodloe
- Department of Chemistry and Physics, Birmingham Southern College, Birmingham, AL 35254, USA.
| | - Yogesh K Vohra
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Baker PA, Thompson RG, Catledge SA. A wear simulation study of nanostructured CVD diamond-on-diamond articulation involving concave/convex mating surfaces. J Coat Technol Res 2016; 13:385-393. [PMID: 26989457 PMCID: PMC4790821 DOI: 10.1007/s11998-015-9738-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Using microwave-plasma Chemical Vapor Deposition (CVD), a 3-micron thick nanostructured-diamond (NSD) layer was deposited onto polished, convex and concave components that were machined from Ti-6Al-4V alloy. These components had the same radius of curvature, 25.4mm. Wear testing of the surfaces was performed by rotating articulation of the diamond-deposited surfaces (diamond-on-diamond) with a load of 225N for a total of 5 million cycles in bovine serum resulting in polishing of the diamond surface and formation of very shallow, linear wear grooves of less than 50nm depth. The two diamond surfaces remained adhered to the components and polished each other to an average surface roughness that was reduced by as much as a factor of 80 for the most polished region located at the center of the condyle. Imaging of the surfaces showed that the initial wearing-in phase of diamond was only beginning at the end of the 5 million cycles. Atomic force microscopy, scanning electron microscopy, Raman spectroscopy, and surface profilometry were used to characterize the surfaces and verify that the diamond remained intact and uniform over the surface, thereby protecting the underlying metal. These wear simulation results show that diamond deposition on Ti alloy has potential application for joint replacement devices with improved longevity over existing devices made of cobalt chrome and ultra-high molecular weight polyethylene (UHMWPE).
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Affiliation(s)
- Paul A Baker
- Vista Engineering, 1500 1st. Ave N. Unit 14, Birmingham, AL 35203 USA
| | | | - Shane A Catledge
- University of Alabama at Birmingham, 1720 2nd Ave. S, Birmingham, AL 35233 USA
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Baker PA, Scott J. Comment on Varghese and Kundu, Does the Miller blade truly provide a better laryngoscopic view and intubating conditions than the Macintosh blade in small children? Paediatr Anaesth 2014; 24:1197-8. [PMID: 25279682 DOI: 10.1111/pan.12545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Paul A Baker
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.
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Schaverien MV, Munro KJ, Baker PA, Munnoch DA. Liposuction for chronic lymphoedema of the upper limb: 5 years of experience. J Plast Reconstr Aesthet Surg 2012; 65:935-42. [DOI: 10.1016/j.bjps.2012.01.021] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 11/11/2011] [Accepted: 01/26/2012] [Indexed: 11/28/2022]
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Clark PU, Shakun JD, Baker PA, Bartlein PJ, Brewer S, Brook E, Carlson AE, Cheng H, Kaufman DS, Liu Z, Marchitto TM, Mix AC, Morrill C, Otto-Bliesner BL, Pahnke K, Russell JM, Whitlock C, Adkins JF, Blois JL, Clark J, Colman SM, Curry WB, Flower BP, He F, Johnson TC, Lynch-Stieglitz J, Markgraf V, McManus J, Mitrovica JX, Moreno PI, Williams JW. Global climate evolution during the last deglaciation. Proc Natl Acad Sci U S A 2012; 109:E1134-42. [PMID: 22331892 PMCID: PMC3358890 DOI: 10.1073/pnas.1116619109] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Deciphering the evolution of global climate from the end of the Last Glacial Maximum approximately 19 ka to the early Holocene 11 ka presents an outstanding opportunity for understanding the transient response of Earth's climate system to external and internal forcings. During this interval of global warming, the decay of ice sheets caused global mean sea level to rise by approximately 80 m; terrestrial and marine ecosystems experienced large disturbances and range shifts; perturbations to the carbon cycle resulted in a net release of the greenhouse gases CO(2) and CH(4) to the atmosphere; and changes in atmosphere and ocean circulation affected the global distribution and fluxes of water and heat. Here we summarize a major effort by the paleoclimate research community to characterize these changes through the development of well-dated, high-resolution records of the deep and intermediate ocean as well as surface climate. Our synthesis indicates that the superposition of two modes explains much of the variability in regional and global climate during the last deglaciation, with a strong association between the first mode and variations in greenhouse gases, and between the second mode and variations in the Atlantic meridional overturning circulation.
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Affiliation(s)
- Peter U. Clark
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
| | - Jeremy D. Shakun
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138
| | - Paul A. Baker
- Division of Earth and Ocean Sciences, Duke University, Durham, NC 27708
| | | | - Simon Brewer
- Department of Geography, University of Utah, Salt Lake City, UT 84112
| | - Ed Brook
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
| | - Anders E. Carlson
- Department of Geoscience, University of Wisconsin, Madison, WI 53706
- Center for Climatic Research, University of Wisconsin, Madison, WI 53706
| | - Hai Cheng
- Institute of Global Environmental Change, Xi’an Jiaotong University, Xi’an 710049, China
- Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455
| | - Darrell S. Kaufman
- School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ 86011
| | - Zhengyu Liu
- Center for Climatic Research, University of Wisconsin, Madison, WI 53706
- Laboratory for Ocean-Atmosphere Studies, School of Physics, Peking University, Beijing 100871, China
| | - Thomas M. Marchitto
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309
| | - Alan C. Mix
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
| | - Carrie Morrill
- National Oceanic and Atmospheric Administration National Climatic Data Center, Boulder, CO 80305
| | - Bette L. Otto-Bliesner
- Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO 80307
| | - Katharina Pahnke
- Department of Geology and Geophysics, University of Hawaii, Honolulu, HI 96822
| | - James M. Russell
- Department of Geological Sciences, Brown University, Providence, RI 02912
| | - Cathy Whitlock
- Department of Earth Sciences, Montana State University, Bozeman, MT 97403
| | - Jess F. Adkins
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125
| | - Jessica L. Blois
- Center for Climatic Research, University of Wisconsin, Madison, WI 53706
- Department of Geography, University of Wisconsin, Madison, WI 53706
| | - Jorie Clark
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331
| | - Steven M. Colman
- Large Lakes Observatory and Department Geological Sciences, University of Minnesota, Duluth, MN 55812
| | - William B. Curry
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
| | - Ben P. Flower
- College of Marine Science, University of South Florida, St. Petersburg, FL 33701
| | - Feng He
- Center for Climatic Research, University of Wisconsin, Madison, WI 53706
| | - Thomas C. Johnson
- Large Lakes Observatory and Department Geological Sciences, University of Minnesota, Duluth, MN 55812
| | - Jean Lynch-Stieglitz
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332
| | - Vera Markgraf
- School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ 86011
| | - Jerry McManus
- Lamont-Doherty Earth Observatory, Palisades, NY 10964; and
| | - Jerry X. Mitrovica
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138
| | - Patricio I. Moreno
- Institute of Ecology and Biodiversity and Department of Ecological Sciences, Universidad de Chile, Santiago 1058, Chile
| | - John W. Williams
- Department of Geography, University of Wisconsin, Madison, WI 53706
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Abstract
In airway management, poor judgment, education and training are leading causes of patient morbidity and mortality. The traditional model of medical education, which relies on experiential learning in the clinical environment, is inconsistent and often inadequate. Curriculum change is underway in many medical organisations in an effort to correct these problems, and airway management is likely to be explicitly addressed as a clinical fundamental within any new anaesthetic curriculum. Competency-based medical education with regular assessment of clinical ability is likely to be introduced for all anaesthetists engaged in airway management. Essential clinical competencies need to be defined and improvements in training techniques can be expected based on medical education research. Practitioners need to understand their equipment and diversify their airway skills to cope with a variety of clinical presentations. Expertise stems from deliberate practice and a desire constantly to improve performance with a career-long commitment to education.
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Affiliation(s)
- P A Baker
- Department of Anaesthesiology, The University of Auckland, New Zealand.
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Abstract
We report the failure of an i-gel and an Ambu AuraOnce supraglottic airway to ventilate a drowning victim. Failure was attributed to changes in lung physiology following submersion and inhalation of water that may have required ventilation pressures up to 40 cmH2O to treat the victim's hypoxaemia. The ease of use and rapid insertion of supraglottic airways without interrupting cardiac compression has prompted recommendations for their use during resuscitation. The relatively low leak pressures attainable from many supraglottic airways, however may cause inadequate lung ventilation and entrainment of air into the stomach when these devices are used in drowning victims.
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Affiliation(s)
- P A Baker
- Department of Anaesthesiology, The University of Auckland, Auckland City Hospital and Starship Children's Health, Auckland, New Zealand.
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Abstract
Dermatofibrosarcoma protuberans (DFSP) is an uncommon, locally aggressive cutaneous tumour of intermediate grade
malignancy. A number of reports have linked local trauma of varying aetiology with the later development of DFSP.
In addition, a variety of skin disorders and, in rare cases, cutaneous tumours, have been described in association with
decorative tattoos. This is often associated with delayed diagnosis. We report the first case of DFSP arising in a tattoo and
discuss the available evidence for a causative link between DFSP and local trauma of this nature.
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Affiliation(s)
- Paul A Baker
- Canniesburn Plastic Surgery Unit Glasgow Royal Infirmary Glasgow G4 0SF Scotland
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Abstract
OBJECTIVE The International Organization for Standardization (ISO) recently published an International Standard (ISO 7376:2009) which specifies illuminance levels and tests for illumination from hook-on type laryngoscopes used for intubation. A clinical study examining luminance for laryngoscopy found that 100 cd·m(-2) was the minimum level acceptable for laryngoscopy. The purpose of this study was to measure the quality of light from laryngoscopes available for use by anesthetists in an anesthetic department and compare them to the ISO illuminance standard and published minimum acceptable luminance limits. METHODS A measuring device was constructed to support each laryngoscope in a standardized manner. For 190 reusable laryngoscopes, illuminance was measured with a lux meter at the base of this device. Eighteen clinically available laryngoscopes were then examined in detail, as a snapshot study, with multiple light recordings according to the ISO Standard. We also measured the luminance provided by each laryngoscope. RESULTS Only two of the 18 laryngoscopes met the minimum illuminance level of 500 lux after 10 min. Nine laryngoscopes provided a luminance <100 cd·m(-2), which is the reported minimum required luminance for laryngoscopy. None of the 18 laryngoscopes tested complied with the ISO standard for laryngoscope light distribution. CONCLUSIONS Laryngoscope light should be regularly audited. Results from these audits can be used to retire or repair substandard laryngoscopes to maintain acceptable standards of laryngoscope light. Audit results produce tangible evidence that is useful when applying for capital expenditure. Light measurements are not easy to make. There needs to be a convenient device to reliably measure laryngoscope illumination.
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Affiliation(s)
- Paul A Baker
- Department of Anaesthesia, Starship Children's Health, Auckland, New Zealand.
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Baker PA, Flanagan BT, Greenland KB, Morris R, Owen H, Riley RH, Runciman WB, Scott DA, Segal R, Smithies WJ, Merry AF. Equipment to manage a difficult airway during anaesthesia. Anaesth Intensive Care 2011; 39:16-34. [PMID: 21375086 DOI: 10.1177/0310057x1103900104] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Airway complications are a leading cause of morbidity and mortality in anaesthesia. Effective management of a difficult airway requires the timely availability of suitable airway equipment. The Australian and New Zealand College of Anaesthetists has recently developed guidelines for the minimum set of equipment needed for the effective management of an unexpected difficult airway (TG4 [2010] www.anzca.edu.au/resources/professionaldocuments). TG4 [2010] is based on expert consensus, underpinned by wide consultation and an extensive review of the available evidence, which is summarised in a Background Paper (TG4 BP [2010] www.anzca.edu.au/ resources/professional-documents). TG4 [2010] will be reviewed at the end of one year and thereafter every five years or more frequently if necessary. The current paper is reproduced directly from the Background Paper (TG4 BP [2010]).
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Affiliation(s)
- P A Baker
- Australian and New Zealand College of Anaesthetists, Melbourne, Victoria, Australia
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Abstract
OBJECTIVE A prospective randomized, controlled trial was conducted comparing supraglottic airways (SGA) for flexible bronchoscopy in 100 children. BACKGROUND Pediatric flexible bronchoscopy is commonly performed using a SGA as both a ventilation device and a conduit for flexible bronchoscopy. We observed that some disposable SGAs were associated with increased resistance to bronchoscope manipulation compared to the LMA Classic (cLMA). METHODS We compared the cLMA to the Ambu Aura Once, Portex Soft Seal, Boss Systems disposable silicone laryngeal mask, and LMA Unique. We recorded the subjective resistance of the bronchoscope manipulation within the SGA by linear analog score and measured the time to insert the bronchoscope from the proximal end of the SGA to the right upper lobe. We also scored the view of the larynx through the bronchoscope and measured SGA cuff pressures. RESULTS Resistance to bronchoscope manipulation during pediatric flexible bronchoscopy was higher using polyvinyl chloride (PVC) disposable SGAs (Ambu, Unique, and Portex) than the silicone re-usable cLMA (P < 0.0001). The Unique and Ambu laryngeal masks were clinically inferior to the cLMA at all levels of the airway (P < 0.0001). The Portex Soft Seal was not different above the larynx but was significantly statistically inferior at (P < 0.04) and below the larynx (P < 0.006) and inferior overall (P < 0.007). Boss Systems single-use laryngeal mask was as effective as the cLMA. CONCLUSION In this trial, PVC single-use laryngeal masks were inferior to the silicone cLMA and Boss Systems laryngeal masks for flexible bronchoscopy in children.
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Affiliation(s)
- Paul A Baker
- Department of Paediatric Anaesthesia, Starship Children's Health, Auckland, New Zealand.
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Abstract
The experimental replacement of calcite and aragonite by dolomite under a variety of conditions indicates that dolomitization can take place in marine and lacustrine environments under two conditions: (i) low dissolved sulfate concentrations and (ii) insubstantial contemporaneous silica diagenesis. Common sites for dolomite formation are areas where the dissolved sulfate concentration is reduced by microbial sulfate reduction, through the mixing of seawater with large amounts of fresh water, or where low-sulfate alkaline lacustrine environments prevail. Even under these conditions, dolomite formation may be inhibited by the concurrent transformation of opal-A (amorphous silica) to opal-CT (disordered cristobalite and tridymite), whereas the subsequent transformation of opal-CT to quartz favors the formation of dolomite.
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Abstract
The Macintosh laryngoscope has been described as 'the most numerously and widely made durable item in the history of anesthesia' (Sir Anthony Jephcott, February 6, 1983). This laryngoscope was originally designed to facilitate intubation in unparalyzed patients and became universally adopted by the anesthetic community. In spite of enormous subsequent changes in anesthetic practice, the Macintosh laryngoscope continues to dominate 50 years after its key indication has become obsolete. This study explores the development and success of this ubiquitous instrument.
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Affiliation(s)
- Jeanette Scott
- Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand
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Abstract
AIM A bench study of the Enk oxygen flow modulator (Enk OFM) was conducted to test its performance and potential use in pediatric patients using the Advanced Paediatric Life Support (APLS) guidelines (Advanced Paediatric Life Support, 2005: 224). BACKGROUND The Enk OFM is a preassembled emergency transtracheal ventilation device. METHODS The Enk OFM was connected to two sources of oxygen: first, to a Precision Medical flowmeter and second, to an Aestiva anesthetic machine axillary flowmeter. Testing was performed on standard cannulae of 20, 18, and 16 gauge caliber and also a 7.5 cm 15G Emergency Transtracheal Airway Catheter (Cook Medical). Serial hole occlusion of the Enk OFM was applied and the resulting flow rates were measured by a RespiCal Timeter. RESULTS Oxygen flow was best controlled by occluding all holes of the Enk OFM and incrementally increasing oxygen flow by the flowmeter with an initial setting of 1 l min(-1) year(-1) of age. Contrary to the original description of this device (Anesth Analg 1998; 86: 203S), sequential occlusion of the five side holes does not lead to a significant exponential increase in gas flow. Incomplete occlusion of the Enk OFM provided insufficient and unpredictable flow. CONCLUSIONS The Enk OFM should be fully occluded for inspiration with flow rates set at 1 l min(-1) year(-1) of age and adjusted to effect. These flow rates are consistent with the APLS recommendations. Flows above 15 l min(-1) are potentially dangerous and the Enk OFM fails to perform as an on-off device. Flowmeter settings of <1 l min(-1) risk no flow. Cannulae of at least 18G should be used for optimal flow.
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Affiliation(s)
- Paul A Baker
- Department of Paediatric Anaesthesia, Starship Children's Health, Park Road, Auckland, New Zealand.
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Baker PA, Hounsell GL. Securing the Aintree Intubation Catheter. Anaesth Intensive Care 2009; 37:136. [PMID: 19157364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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Baker PA, Fritz SC, Burns SJ, Ekdahl E, Rigsby CA. The Nature and Origin of Decadal to Millennial Scale Climate Variability in the Southern Tropics of South America: The Holocene Record of Lago Umayo, Peru. Past Climate Variability in South America and Surrounding Regions 2009. [DOI: 10.1007/978-90-481-2672-9_13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Williams AM, Baker PA, Platt AJ. The impact of dressings on recovery from carpal tunnel decompression. J Plast Reconstr Aesthet Surg 2008; 61:1493-5. [DOI: 10.1016/j.bjps.2007.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2006] [Revised: 03/22/2007] [Accepted: 10/01/2007] [Indexed: 01/08/2023]
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Affiliation(s)
- P A Baker
- Department of Plastic & Reconstructive Surgery, St. John's Hospital, Howden Road West, Livingston, United Kingdom.
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Baker PA, Watson SB. Functional gracilis flap in thenar reconstruction. J Plast Reconstr Aesthet Surg 2007; 60:828-34. [PMID: 17448743 DOI: 10.1016/j.bjps.2007.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Revised: 12/01/2006] [Accepted: 03/01/2007] [Indexed: 11/17/2022]
Abstract
UNLABELLED Restoration of lost opposition in the context of significant thenar soft tissue defects represents a tremendous reconstructive challenge. Free functioning muscle transfer has been described in this context and has the advantage of providing both a functioning muscle unit as well as soft tissue coverage in a single reconstructive procedure. It adds to the injured limb, and by sparing donor tendons avoids the need for re-education of motor function. We describe the use of a free innervated gracilis muscle flap for functional thenar reconstruction in two unique cases following extensive traumatic loss of thenar skin and musculature. Crucially, in each case, the recurrent motor branch of the median nerve had been destroyed at its point of insertion into the thenar muscle remnants. AIM To date, the main reported disadvantages of free functioning muscle transfer in thenar reconstruction include difficult flap dissections, donor site morbidity, inadequate strength and excursion of the transplanted muscle and excessively bulky flaps. Our aim was, as far as possible, to address these issues. SURGICAL PROCEDURE Each thenar defect was measured and a corresponding segment of gracilis muscle, measured in situ, was raised on the proximal neurovascular pedicle. End-side microvascular anastomosis was performed between the medial circumflex femoral artery and the radial artery. The venae comitantes of the pedicle were anastomosed end-end with those of the radial artery and also with the cephalic vein. Epineural anastomosis was performed between the motor branch of the obturator nerve and the recurrent motor branch of the median nerve. Each flap was covered with a split thickness skin graft. RESULTS Both flaps survived without any complication. Both patients regained excellent voluntary thumb opposition, sufficient to allow return to full-time employment, and had restoration of sufficient thenar bulk. This was achieved with minimal donor site morbidity. CONCLUSIONS Restoration of lost opposition, in the context of significant thenar soft tissue defects, can be achieved using a free functional gracilis flap. This produces clinically excellent functional results and can be carried out as a single stage reconstructive procedure. This is a novel application of a tremendously versatile donor muscle in functioning free muscle transfer.
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Affiliation(s)
- P A Baker
- Canniesburn Plastic Surgery Unit, Glasgow Royal Infirmary, 84 Castle Street, Glasgow G4 0SF, UK
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Abstract
Nonsyndromal dysgnathia is a rare disorder with a probable genetic basis characterized by a hypoplastic or absent mandible (agnathia), microstomia, microglossia, and ear anomalies secondary to a defect in the ventral portion of the first branchial arch caused by defective neural crest migration or proliferation. Dysgnathic newborn infants often suffer fatal respiratory failure from airway obstruction. Nineteen children with isolated dysgnathia complex are described in the literature--six were stillborn, eight died shortly after birth, and only five survived infancy. All survivors required tracheostomy to maintain an airway. It is difficult to intubate the trachea of these children and early airway management planning is important. We report a neonate who presented with a prenatal ultrasound diagnosis of severe micrognathia, polyhydramnios and a family history of severe micrognathia. Airway management was achieved with fiberoptic intubation through a laryngeal mask airway (LMA) during an ex utero intrapartum treatment procedure. Fiberoptic intubation was hampered by copious amounts of amniotic fluid. This child and her sibling are the first two siblings with isolated dysgnathia complex to have survived infancy and provide further support for a genetic basis to this condition.
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Affiliation(s)
- Paul A Baker
- Department of Anaesthesia, Auckland Children's Hospital, Park Road, Auckland, New Zealand.
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Seltzer GO, Rodbell DT, Baker PA, Fritz SC, Tapia PM, Rowe HD, Dunbar RB. Early warming of tropical South America at the last glacial-interglacial transition. Science 2002; 296:1685-6. [PMID: 12040193 DOI: 10.1126/science.1070136] [Citation(s) in RCA: 148] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Glaciation in the humid tropical Andes is a sensitive indicator of mean annual temperature. Here, we present sedimentological data from lakes beyond the glacial limit in the tropical Andes indicating that deglaciation from the Last Glacial Maximum led substantial warming at high northern latitudes. Deglaciation from glacial maximum positions at Lake Titicaca, Peru/Bolivia (16 degrees S), and Lake Junin, Peru (11 degrees S), occurred 22,000 to 19,500 calendar years before the present, several thousand years before the Bølling-Allerød warming of the Northern Hemisphere and deglaciation of the Sierra Nevada, United States (36.5 degrees to 38 degrees N). The tropical Andes deglaciated while climatic conditions remained regionally wet, which reflects the dominant control of mean annual temperature on tropical glaciation.
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Affiliation(s)
- G O Seltzer
- Department of Earth Sciences, Syracuse University, 204 Heroy Geology Laboratory, Syracuse, NY 13244, USA.
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Affiliation(s)
- Paul A Baker
- Duke University, Nicholas School of the Environment and Earth Science, Division of Earth and Ocean Sciences, Durham, NC 27708, USA
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Dwyer GS, Cronin TM, Baker PA. Trace elements in marine ostracodes. ACTA ACUST UNITED AC 2002. [DOI: 10.1029/131gm11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
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Baker PA, Catledge SA, Vohra YK. Low-temperature growth of nanostructured diamond films. J Nanosci Nanotechnol 2001; 1:31-34. [PMID: 12914027 DOI: 10.1166/jnn.2001.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Nanostructured diamond films are grown on a titanium alloy substrate using a two-step deposition process. The first step is performed at elevated temperature (820 degrees C) for 30 min using a H2/CH4/N2 gas mixture to grow a thin (approximately 600 nm) nanostructured diamond layer and to improve film adhesion. The remainder of the deposition involves growth at low temperature (< 600 degrees C) in a H2/CH4/O2 gas mixture. The continuation of the smooth nanostructured diamond film growth during low-temperature deposition is confirmed by in situ laser reflectance interferometry, atomic force microscopy, micro-Raman spectroscopy, and surface profilometry. Similar experiments performed without the initial nanostructured diamond layer resulted in poorly adhered films with a more crystalline appearance and a higher surface roughness. This low-temperature deposition of nanostructured diamond films on metals offers advantages in cases where high residual thermal stress leads to delamination at high temperatures.
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Affiliation(s)
- P A Baker
- Physics Department, University of Alabama at Birmingham, Birmingham, Alabama 35294-1170, USA
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