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Choi EJ, Levin D, Robertson A, Kirkham FJ, Muthusami P, Krishnan P, Shroff M, Moharir M, Dirks P, MacGregor D, Pulcine E, Bhathal I, Kassner A, Walker K, Allan W, deVeber G, Logan WJ, Dlamini N. Assessment of MR blood-oxygen-level-dependent (BOLD) cerebrovascular reactivity under general anesthesia in children with moyamoya. Pediatr Radiol 2024; 54:1325-1336. [PMID: 38777883 DOI: 10.1007/s00247-024-05930-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 04/02/2024] [Accepted: 04/11/2024] [Indexed: 05/25/2024]
Abstract
BACKGROUND Moyamoya is a progressive, non-atherosclerotic cerebral arteriopathy that may present in childhood and currently has no cure. Early diagnosis is critical to prevent a lifelong risk of neurological morbidity. Blood-oxygen-level-dependent (BOLD) MRI cerebrovascular reactivity (CVR) imaging provides a non-invasive, in vivo measure of autoregulatory capacity and cerebrovascular reserve. However, non-compliant or younger children require general anesthesia to achieve BOLD-CVR imaging. OBJECTIVE To determine the same-day repeatability of BOLD-CVR imaging under general anesthesia in children with moyamoya. MATERIALS AND METHODS Twenty-eight examination pairs were included (mean patient age = 7.3 ± 4.0 years). Positive and negatively reacting voxels were averaged over signals and counted over brain tissue and vascular territory. The intraclass correlation coefficient (ICC), Wilcoxon signed-rank test, and Bland-Altman plots were used to assess the variability between the scans. RESULTS There was excellent-to-good (≥ 0.59) within-day repeatability in 18 out of 28 paired studies (64.3%). Wilcoxon signed-rank tests demonstrated no significant difference in the grey and white matter CVR estimates, between repeat scans (all p-values > 0.05). Bland-Altman plots of differences in mean magnitude of positive and negative and fractional positive and negative CVR estimates illustrated a reasonable degree of agreement between repeat scans and no systematic bias. CONCLUSION BOLD-CVR imaging provides repeatable assessment of cerebrovascular reserve in children with moyamoya imaged under general anesthesia.
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Affiliation(s)
- Eun Jung Choi
- Neurosciences and Mental Health Program, The Hospital for Sick Children, Toronto, Canada
- Stroke Imaging Lab for Children, Peter Gilgan Centre for Research & Learning, Toronto, ON, Canada
| | - David Levin
- Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, Toronto, Canada
| | - Amanda Robertson
- Neurosciences and Mental Health Program, The Hospital for Sick Children, Toronto, Canada
- Stroke Imaging Lab for Children, Peter Gilgan Centre for Research & Learning, Toronto, ON, Canada
- Division of Neurology, The Hospital for Sick Children, Toronto, Canada
| | - Fenella J Kirkham
- Developmental Neurosciences and Biomedical Research Centre, University College London Great Ormond Street Institute of Child Health, London, UK
| | - Prakash Muthusami
- Diagnostic Imaging and Interventional Radiology, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Pradeep Krishnan
- Diagnostic Imaging and Interventional Radiology, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Manohar Shroff
- Diagnostic Imaging and Interventional Radiology, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | | | - Peter Dirks
- Department of Neurosurgery, The Hospital for Sick Children, Toronto, Canada
| | - Daune MacGregor
- Division of Neurology, The Hospital for Sick Children, Toronto, Canada
| | - Elizabeth Pulcine
- Division of Neurology, The Hospital for Sick Children, Toronto, Canada
| | - Ishvinder Bhathal
- Division of Neurology, The Hospital for Sick Children, Toronto, Canada
| | - Andrea Kassner
- Stroke Imaging Lab for Children, Peter Gilgan Centre for Research & Learning, Toronto, ON, Canada
- Medical Imaging, University of Toronto, Toronto, ON, Canada
| | - Kirstin Walker
- Neurosciences and Mental Health Program, The Hospital for Sick Children, Toronto, Canada
- Stroke Imaging Lab for Children, Peter Gilgan Centre for Research & Learning, Toronto, ON, Canada
- Division of Neurology, The Hospital for Sick Children, Toronto, Canada
| | - Warwick Allan
- Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, Toronto, Canada
| | - Gabrielle deVeber
- Stroke Imaging Lab for Children, Peter Gilgan Centre for Research & Learning, Toronto, ON, Canada
- Division of Neurology, The Hospital for Sick Children, Toronto, Canada
- Child Health Evaluative Sciences Program, The Hospital for Sick Children, Toronto, Canada
| | - William J Logan
- Division of Neurology, The Hospital for Sick Children, Toronto, Canada
| | - Nomazulu Dlamini
- Neurosciences and Mental Health Program, The Hospital for Sick Children, Toronto, Canada.
- Stroke Imaging Lab for Children, Peter Gilgan Centre for Research & Learning, Toronto, ON, Canada.
- Division of Neurology, The Hospital for Sick Children, Toronto, Canada.
- Child Health Evaluative Sciences Program, The Hospital for Sick Children, Toronto, Canada.
- Department of Paediatrics, Division of Neurology, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, MX5 1X8, Canada.
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Luigi C, Stefania DS. Nitrous oxide intoxication: systematic literature review and proposal of new diagnostic possibilities. EGYPTIAN JOURNAL OF FORENSIC SCIENCES 2022. [DOI: 10.1186/s41935-022-00315-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Abstract
Background
Nitrous oxide (N2O), also called “laughing gas,” is the most commonly used inhalation anesthetic in dentistry. The N2O is no longer used, because of the long-term neurologic and cardiovascular sequelae. Due to its sedative and euphoric properties, N2O is often used for recreational use or in some erotic activities. Accidental deaths are mainly associated with the uses of N2O: death can occur from sudden cardiac arrhythmia or, most commonly, acute asphyxiation due to hypoxia. This paper aims to study the literature concerning deaths due to N2O intoxication and highlight pathological findings useful for diagnosis when the crime scene investigation does not reveal any evidence.
Materials and methods
The authors conducted the literature search by PubMed and Scopus databases, searching for articles from 1 January 1970 to 1 March 2020 using the key terms: “Nitrous oxide,” “Laughing gas,” “Hypoxic damage,” “Nitrous oxide anesthesia,” and “Nitrous oxide death.”
Results and discussion
A total of 244 articles were collected. Only 26 articles were included in the systematic review. Most of the deaths from intoxication are due to asphyxiation; the diagnosis is often difficult and immunohistochemistry could be helpful. Nitrous oxide increases the intracellular adhesion molecule expression, E- and P-Selectin (markers of the early inflammatory response), and HIF-1 α (indicative of oxidative stress during ischemia-reperfusion).
Conclusion
The macroscopic and microscopic signs of N2O intoxication are non-specific, but N2O has been proven to cause hypoxic damage to the brain. The suspicion of the presence of the gas in the environment should guide the pathologist. Tissue analyzes provide important information; immunohistochemical stains can confirm hypoxic damage through the use of markers such as HIF-1 α, E-Selectin, and P-Selectin.
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Cui B, Ou-Yang C, Xie S, Lin D, Ma J. Age-related cerebrovascular carbon dioxide reactivity in children with ventricular septal defect younger than 3 years. Paediatr Anaesth 2020; 30:977-983. [PMID: 32648613 DOI: 10.1111/pan.13967] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 06/24/2020] [Accepted: 07/03/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND Impaired cerebrovascular reactivity to carbon dioxide was proposed to contribute to neurological morbidity in children undergoing cardiac surgery. The objective of this study was to assess carbon dioxide reactivity and regional cerebral oxygen saturation in children younger than 3 years. METHODS This study enrolled children younger than 3 years undergoing ventricular septal defect repair. The cohort was divided into three age groups: younger than 6 months, 6-12 months, and 12-36 months. Under steady-state anesthesia, carbon dioxide reactivity was calculated by measuring changes in middle cerebral artery blood flow velocity using transcranial Doppler sonography. Regional cerebral oxygen saturation changes were measured by near-infrared spectroscopy while endtidal carbon dioxide pressure was adjusted from 30 to 45 mm Hg. RESULTS Carbon dioxide reactivity showed a statistically significant increasing relationship with age (younger than 6 months group: 4.42% ± 2.73%, 6-12 months group: 5.86% ± 1.91%, 12-36 months group: 7.58% ± 1.49%; P < .001). Regional cerebral oxygen saturation showed a statistically significant increasing relationship with age (younger than 6 months group: 65% ± 6%, 6-12 months group: 68% ± 5%, 12-36 months group: 70% ± 5%; P = .027). Regional cerebral oxygen saturation showed a statistically significant increasing relationship with endtidal carbon dioxide pressure in all children (P < .001). CONCLUSION Abnormal carbon dioxide reactivity is prevalent in children younger than 3 years and the degree varies according to age.
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Affiliation(s)
- Boqun Cui
- Anesthesia Center, Capital Medical University Affiliated Beijing Anzhen Hospital, Beijing, China
| | - Chuan Ou-Yang
- Anesthesia Center, Capital Medical University Affiliated Beijing Anzhen Hospital, Beijing, China
| | - Siyuan Xie
- Anesthesia Center, Capital Medical University Affiliated Beijing Anzhen Hospital, Beijing, China.,Department of Anesthesiology, Capital Institute of Pediatrics affiliated Children's Hospital, Beijing, China
| | - Duomao Lin
- Anesthesia Center, Capital Medical University Affiliated Beijing Anzhen Hospital, Beijing, China
| | - Jun Ma
- Anesthesia Center, Capital Medical University Affiliated Beijing Anzhen Hospital, Beijing, China
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Lauder GR, Thomas M, von Ungern-Sternberg BS, Engelhardt T. Volatiles or TIVA: Which is the standard of care for pediatric airway procedures? A pro-con discussion. Paediatr Anaesth 2020; 30:209-220. [PMID: 31886922 DOI: 10.1111/pan.13809] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/24/2019] [Accepted: 12/26/2019] [Indexed: 12/21/2022]
Abstract
Anesthesia for pediatric airway procedures constitutes a true art form that requires training and experience. Communication between anesthetist and surgeon to establish procedure goals is essential in determining the most appropriate anesthetic management. But does the mode of anesthesia have an impact? Traditionally, inhalational anesthesia was the most common anesthesia technique used during airway surgery. Introduction of agents used for total intravenous anesthesia (TIVA) such as propofol, short-acting opioids, midazolam, and dexmedetomidine has driven change in practice. Ongoing debates abound as to the advantages and disadvantages of volatile-based anesthesia versus TIVA. This pro-con discussion examines both volatiles and TIVA, from the perspective of effectiveness, safety, cost, and environmental impact, in an endeavor to justify which technique is the best specifically for pediatric airway procedures.
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Affiliation(s)
- Gillian R Lauder
- Department of Anesthesia, BC Children's Hospital, Vancouver, Canada.,Department of Anesthesiology, Pharmacology & Therapeutics, University of British Columbia, Vancouver, Canada
| | - Mark Thomas
- Department of Anaesthesia, Great Ormond St Hospital, London, UK
| | - Britta S von Ungern-Sternberg
- Department of Anaesthesia and Pain Management, Perth Children's Hospital, Perth, Australia.,Medical School, The University of Western Australia, Perth, Australia.,Telethon Kids Institute, Perth, Australia
| | - Thomas Engelhardt
- Department of Anesthesia, McGill University Health Centre, Montreal Children's Hospital, Montreal, QC, Canada
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Verma RK, Keller D, Grunt S, Bigi S, Weisstanner C, Wiest R, Gralla J, Hutter D, Wagner B. Decreased oxygen saturation levels in neonates with transposition of great arteries: Impact on appearance of cerebral veins in susceptibility-weighted imaging. Sci Rep 2017; 7:15471. [PMID: 29133891 PMCID: PMC5684390 DOI: 10.1038/s41598-017-15591-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/27/2017] [Indexed: 12/24/2022] Open
Abstract
Purpose of this study was to investigate a potential correlation between the pattern of cerebral veins (CV) on susceptibility-weighted imaging (SWI) and blood oxygen saturation, as well as preoperative brain injury, in neonates with transposition of the great arteries (TGA). Eleven neonates with TGA underwent MRI preoperatively, including SWI, T1- and T2-weighted scans. Images were retrospectively evaluated and appearance of CV was graded from 0 (normal appearance) to 3 (severe prominent appearance). White matter injuries (WMI) and strokes were analysed. Results were correlated with preductal arterial oxygen saturation. As findings one subject showed a normal CV appearance (grade 0) whereas 10 showed pathological prominent CV (grades 1–3); median 2. Mean oxygen saturation ranged between 67.5% and 89.0% (median 81.0%). CV grade and mean oxygen saturation correlated significantly (p = 0.011). WMI were absent in 5 cases, mild in 4, and moderate in 2 cases. We conclude, that SWI has the potential to be used to estimate the current hypoxic burden on brain tissue in TGA newborns by assessing the prominence of the CV.
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Affiliation(s)
- Rajeev Kumar Verma
- University Institute of Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland. .,Institute of Radiology and Neuroradiology, Tiefenau Hospital, Division Stadt, Inselgroup, Bern, Switzerland.
| | - Desislava Keller
- University Institute of Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland
| | - Sebastian Grunt
- University Department of Pediatrics, Division of Pediatric Neurology, Development and Rehabilitation, Inselspital, University of Bern, Bern, Switzerland
| | - Sandra Bigi
- University Department of Pediatrics, Division of Pediatric Neurology, Development and Rehabilitation, Inselspital, University of Bern, Bern, Switzerland
| | - Christian Weisstanner
- University Institute of Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland
| | - Roland Wiest
- University Institute of Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland
| | - Jan Gralla
- University Institute of Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland
| | - Damian Hutter
- University Department of Pediatrics, Division of Pediatric Cardiology, Inselspital, University of Bern, Bern, Switzerland
| | - Bendicht Wagner
- University Department of Pediatrics, Division of Pediatric Intensive Care Medicine, Inselspital Bern, University of Bern, Bern, Switzerland
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Löbel U, Forkert ND, Schmitt P, Dohrmann T, Schroeder M, Magnus T, Kluge S, Weiler-Normann C, Bi X, Fiehler J, Sedlacik J. Cerebral Hemodynamics in Patients with Hemolytic Uremic Syndrome Assessed by Susceptibility Weighted Imaging and Four-Dimensional Non-Contrast MR Angiography. PLoS One 2016; 11:e0164863. [PMID: 27802295 PMCID: PMC5089757 DOI: 10.1371/journal.pone.0164863] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 10/03/2016] [Indexed: 11/18/2022] Open
Abstract
Background and Purpose Conventional magnetic resonance imaging (MRI) of patients with hemolytic uremic syndrome (HUS) and neurological symptoms performed during an epidemic outbreak of Escherichia coli O104:H4 in Northern Europe has previously shown pathological changes in only approximately 50% of patients. In contrast, susceptibility-weighted imaging (SWI) revealed a loss of venous contrast in a large number of patients. We hypothesized that this observation may be due to an increase in cerebral blood flow (CBF) and aimed to identify a plausible cause. Materials and Methods Baseline 1.5T MRI scans of 36 patients (female, 26; male, 10; mean age, 38.2±19.3 years) were evaluated. Venous contrast was rated on standard SWI minimum intensity projections. A prototype four-dimensional (time resolved) magnetic resonance angiography (4D MRA) assessed cerebral hemodynamics by global time-to-peak (TTP), as a surrogate marker for CBF. Clinical parameters studied were hemoglobin, hematocrit, creatinine, urea levels, blood pressure, heart rate, and end-tidal CO2. Results SWI venous contrast was abnormally low in 33 of 36 patients. TTP ranged from 3.7 to 10.2 frames (mean, 7.9 ± 1.4). Hemoglobin at the time of MRI (n = 35) was decreased in all patients (range, 5.0 to 12.6 g/dL; mean, 8.2 ± 1.4); hematocrit (n = 33) was abnormally low in all but a single patient (range, 14.3 to 37.2%; mean, 23.7 ± 4.2). Creatinine was abnormally high in 30 of 36 patients (83%) (range, 0.8 to 9.7; mean, 3.7 ± 2.2). SWI venous contrast correlated significantly with hemoglobin (r = 0.52, P = 0.0015), hematocrit (r = 0.65, P < 0.001), and TTP (r = 0.35, P = 0.036). No correlation of SWI with blood pressure, heart rate, end-tidal CO2, creatinine, and urea level was observed. Findings suggest that the loss of venous contrast is related to an increase in CBF secondary to severe anemia related to HUS. SWI contrast of patients with pathological conventional MRI findings was significantly lower compared to patients with normal MRI (mean SWI score, 1.41 and 2.05, respectively; P = 0.04). In patients with abnormal conventional MRI, mean TTP (7.45), mean hemoglobin (7.65), and mean hematocrit (22.0) were lower compared to patients with normal conventional MRI scans (mean TTP = 8.28, mean hemoglobin = 8.63, mean hematocrit = 25.23). Conclusion In contrast to conventional MRI, almost all patients showed pathological changes in cerebral hemodynamics assessed by SWI and 4D MRA. Loss of venous contrast on SWI is most likely the result of an increase in CBF and may be related to the acute onset of anemia. Future studies will be needed to assess a possible therapeutic effect of blood transfusions in patients with HUS and neurological symptoms.
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Affiliation(s)
- Ulrike Löbel
- Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail:
| | - Nils Daniel Forkert
- Department of Radiology and Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | | | - Torsten Dohrmann
- Department of Intensive Care, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Maria Schroeder
- Department of Intensive Care, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tim Magnus
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Stefan Kluge
- Department of Intensive Care, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christina Weiler-Normann
- Department of Internal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Martin Zeitz Center for Rare Diseases, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Xiaoming Bi
- Siemens Healthcare, Los Angeles, California, United States
| | - Jens Fiehler
- Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jan Sedlacik
- Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Lauder GR. Total intravenous anesthesia will supercede inhalational anesthesia in pediatric anesthetic practice. Paediatr Anaesth 2015; 25:52-64. [PMID: 25312700 DOI: 10.1111/pan.12553] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/09/2014] [Indexed: 11/29/2022]
Abstract
Inhalational anesthesia has dominated the practice of pediatric anesthesia. However, as the introduction of agents such as propofol, short-acting opioids, midazolam, and dexmedetomidine a monumental change has occurred. With increasing use, the overwhelming advantages of total intravenous anesthesia (TIVA) have emerged and driven change in practice. These advantages, outlined in this review, will justify why TIVA will supercede inhalational anesthesia in future pediatric anesthetic practice.
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Affiliation(s)
- Gillian R Lauder
- Department of Pediatric Anesthesia, British Columbia's Children's Hospital, Vancouver, BC, Canada
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de Vasconcellos K, Sneyd JR. Nitrous oxide: are we still in equipoise? A qualitative review of current controversies. Br J Anaesth 2013; 111:877-85. [PMID: 23801743 DOI: 10.1093/bja/aet215] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
This review considers the current position of nitrous oxide in anaesthetic practice and balances potential beneficial and disadvantageous effects. The classic adverse characteristics of nitrous oxide, such as diffusion hypoxia, expansion of gas-filled spaces, and postoperative nausea and vomiting, are often cited as reasons to avoid this old drug. Recent concerns regarding neurotoxicity, adverse cardiovascular outcomes, and wound complications have further hardened many practitioners against nitrous oxide. New evidence and underpinning mechanistic data, however, suggest potential beneficial effects on the central nervous system, cardiovascular system, and acute and chronic pain. While we await the outcome of large studies including ENIGMA-II, many clinicians have already decided against this agent. The authors argue that this abandonment may be premature. Clinical Trial Registration None required.
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Affiliation(s)
- K de Vasconcellos
- Department of Anaesthetics and Critical Care, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
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Abstract
OBJECTIVE The objective of this review was to provide a general descriptive account of the physical properties, end-organ effects, therapeutic applications, and delivery techniques of nitrous oxide (N2O) as used in the arena of procedural sedation. DATA SOURCE A computerized bibliographic search regarding the applications of nitrous for provision of sedation and analgesia during procedures with an emphasis on the pediatric population was performed. RESULTS The end-organ effects of N2O have been well described in the operating room setting. Aside from its effects on the central nervous system of sedation and analgesia, N2O may alter intracerebral dynamics and alter cerebral blood flow and intracranial pressure especially in patients with altered intracranial compliance. Effects on ventilation include a dose-related depression of ventilatory function and control of upper airway patency. These effects are generally limited in the absence of comorbid diseases and potentiated by other sedative and analgesic agents. The more clinically significant respiratory effect of N2O on ventilatory function is a dose-dependent depression of the ventilatory response to hypoxemia. Hemodynamic effects include a mild direct depressant effect on myocardial function, which in the absence of comorbid cardiac disease is generally compensated by stimulation of the sympathetic nervous system. Nitrous oxide may potentially aggravate pulmonary hypertension. Additional physiologic effects on neurologic and hematologic function may result in inactivation of the enzyme, methionine synthetase. Recent concern has also been raised regarding the potential effects of N2O on immune function and its relationship to perioperative surgical site infections. Given differences in the solubility, N2O will diffuse into and significantly expand gas-filled cavities. Chronic exposure of health care works to N2O is also a concern. Although there are limited data in the literature to clearly substantiate concerns regarding the reproductive toxicity of occupational exposure to N2O, appropriate scavenging and use of other techniques are mandatory. Nitrous oxide has been shown to be effective for a variety of minor surgical procedures such as venipuncture, intravenous cannula placement, lumbar puncture, bone marrow aspiration, laceration repair, dental care, and minor dermatologic procedures. It is generally as effective as midazolam, with several studies demonstrating it to be more effective. However, its utility is not as great in severely painful procedures such as fracture reduction. Demonstrated advantages to parenteral sedation include a more rapid onset and a shorter recovery time with the majority of patients preferring it to over other agents or agreeing to its use for subsequent procedures. The literature also suggests increased success rates with simple procedures such as intravenous cannula placement when compared with placebo. In general, life-threatening adverse events have not been reported. Most common adverse effects include dysphoria and vomiting. For more painful procedures, combination with another agent may be used, and in all cases, topical or infiltrative local anesthesia is recommended. CONCLUSIONS In general, N2O is a useful adjunct for procedural sedation. Given the variety of procedures performed in the pediatric patient, ongoing research is required to identify the most appropriate and effective use of this agent. This may be particularly relevant when evaluating its use for procedures associated with significant pain. In these scenarios, the combination of N2O with other agents needs to be evaluated. Given the potential for adverse effects, strict adherence to published guidelines regarding procedural sedation and monitoring is suggested.
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Siriussawakul A, Sharma D, Sookplung P, Armstead W, Vavilala MS. Gender differences in cerebrovascular reactivity to carbon dioxide during sevoflurane anesthesia in children: preliminary findings. Paediatr Anaesth 2011; 21:141-7. [PMID: 21210883 DOI: 10.1111/j.1460-9592.2010.03498.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Cerebrovascular reactivity to carbon dioxide (CO(2) R) is affected by age, gender and anesthetic agents. While gender differences in CO(2) R are described in adults, there are no such data in children. AIM To examine the gender differences in CO(2) R in children during sevoflurane anesthesia. METHODS Five girls and five boys <15 years of age and ASA physical status I, undergoing general anesthesia for elective surgery were enrolled. Under steady-state anesthesia with <1.0 MAC sevoflurane, middle cerebral artery blood flow velocity changes were monitored using Transcranial Doppler ultrasound while endtidal carbon dioxide (EtCO(2)) was adjusted from 40 to 30 mmHg (hypocapnia) and then from 40 to 50 mmHg (hypercapnia). CO(2)R was calculated between EtCO(2) ranges 30-40 and 40-50 mmHg. Cerebrovascular resistance (eCVR) was estimated as MAP/Vmca and the change in eCVR (ΔeCVR) between EtCO(2) 30 and 40 mmHg and between EtCO(2) 40 and 50 mmHg was calculated. RESULTS There was no gender difference in CO(2)R. However, both CO(2)R and ΔeCVR were lower in the EtCO(2) 40-50 mmHg range compared to EtCO(2) 30-40 mmHg range only in girls (P = 0.01 and P = 0.01, respectively). Vmca increased significantly with increase in CO(2) (P < 0.001) for both boys and girls. The coefficient of nonlinear correlation (r) between Vmca and EtCO(2) was 0.88 in girls vs 0.66 in boys. CONCLUSION While there were no gender differences in CO(2)R within the individual EtCO(2) ranges examined, girls but not boys had a significantly lower CO(2)R and ΔeCVR in the higher EtCO(2) range during <1.0 MAC sevoflurane anesthesia.
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Affiliation(s)
- Arunotai Siriussawakul
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA
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Is nitrous oxide use appropriate in neurosurgical and neurologically at-risk patients? Curr Opin Anaesthesiol 2010; 23:544-50. [PMID: 20689409 DOI: 10.1097/aco.0b013e32833e1520] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PURPOSE OF REVIEW To address controversial issues surrounding the use of nitrous oxide as a component of anesthesia in neurosurgical and neurologically at-risk patients. RECENT FINDINGS Nitrous oxide has been used as a component of general anesthesia for over 160 years and has contributed to countless apparently uneventful anesthetics in neurologically at-risk patients. Avoidance of nitrous oxide in specific circumstances, such as pre-existing pneumocephalus, during acute venous air embolism, and in patients with disorders of folate metabolism, is warranted. However, various controversies exist regarding the use of this drug in the general neurosurgical population. Specifically, some suggest a possible association between nitrous oxide and the postoperative development of tension pneumocephalus despite lack of data to support this notion. Additionally, data describing alterations of cerebral hemodynamics and metabolism and exacerbation of ischemic neurologic injury by nitrous oxide are inconsistent. Recent data derived from humans having cerebral aneurysm clipping failed to show any long-term adverse effect from the use of nitrous oxide on gross neurologic or cognitive function. SUMMARY Except in a few specific circumstances, there exists no conclusive evidence to support the dogmatic avoidance of nitrous oxide in neurosurgical patients.
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Sedlacik J, Löbel U, Kocak M, Loeffler RB, Reichenbach JR, Broniscer A, Patay Z, Hillenbrand CM. Attenuation of cerebral venous contrast in susceptibility-weighted imaging of spontaneously breathing pediatric patients sedated with propofol. AJNR Am J Neuroradiol 2010; 31:901-6. [PMID: 20053806 DOI: 10.3174/ajnr.a1960] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND AND PURPOSE SWI is known for its detailed visualization of the cerebral venous system and seems to be a promising tool for early detection of cerebrovascular pathologies in children, who are frequently sedated for MR imaging. Because sedation influences cerebral hemodynamics, we hypothesized that it would affect cerebral venous contrast in SWI. MATERIALS AND METHODS SWI (125 examinations) of 26 patients (age, 2-16 years) was reviewed in this study. Images were acquired of patients sedated with propofol. Reviewers classified the images by weak or strong venous contrast. Physiologic data, such as etCO(2), BP, age, and CBF by arterial spin-labeling, were monitored and collected during MR imaging. A generalized estimating equation approach was used to model associations of these parameters with venous contrast. RESULTS EtCO(2) and CBF were found to correlate with venous contrast, suggesting that patients with high etCO(2) and CBF have weak contrast and patients with low etCO(2) and CBF have strong contrast. BP was also found to correlate with the venous contrast of SWI, suggesting that patients with high BP have strong venous contrast. No significant correlations were found for any other physiologic parameters. CONCLUSIONS We found that the venous contrast in SWI is affected by propofol sedation in spontaneously breathing patients. We also found that low etCO(2), low CBF, and high BP are associated with strong venous contrast. Reviewing SWI data in light of physiologic measures may therefore help prevent potential misinterpretations of weak venous contrast in SWI examinations under propofol sedation.
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Affiliation(s)
- J Sedlacik
- Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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Szabó EZ, Luginbuehl I, Bissonnette B. Impact of anesthetic agents on cerebrovascular physiology in children. Paediatr Anaesth 2009; 19:108-18. [PMID: 19040505 DOI: 10.1111/j.1460-9592.2008.02826.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of the pediatric neuroanesthetist is to provide comprehensive care to children with neurologic pathologies. The cerebral physiology is influenced by the developmental stage of the child. The understanding of the effects of anesthetic agents on the physiology of cerebral vasculature in the pediatric population has significantly increased in the past decade allowing a more rationale decision making in anesthesia management. Although no single anesthetic technique can be recommended, sound knowledge of the principles of cerebral physiology and anesthetic neuropharmacology will facilitate the care of pediatric neurosurgical patients.
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Affiliation(s)
- Elöd Z Szabó
- Department of Anaesthesia, University of Toronto, Toronto, ON, Canada.
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15
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Fodale V, Schifilliti D, Conti A, Lucanto T, Pino G, Santamaria LB. Transcranial Doppler and anesthetics. Acta Anaesthesiol Scand 2007; 51:839-47. [PMID: 17635391 DOI: 10.1111/j.1399-6576.2007.01355.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Transcranial Doppler (TCD) is widely used to investigate the effects of anesthetic drugs on cerebral blood flow. Its repeatability and non-invasivity makes it an ideal, first choice method. Anesthesia providers are required to be conscious of the cerebral hemodynamic effects of drugs given in their practice, especially in neurosurgery and in subjects with impaired brain functions. The purpose of this review is to present the basic concepts of the TCD technique and the effects on cerebral hemodynamics of the most popular anesthetic drugs evaluated using TCD ultrasonography.
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Affiliation(s)
- V Fodale
- Department of Neuroscience, Psychiatric and Anesthesiological Sciences, University of Messina, Messina, Italy.
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Muñoz HR, Cortínez LI, Ibacache ME, Altermatt FR. Remifentanil Requirements During Propofol Administration to Block the Somatic Response to Skin Incision in Children and Adults. Anesth Analg 2007; 104:77-80. [PMID: 17179247 DOI: 10.1213/01.ane.0000251201.81210.e7] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND During sevoflurane administration, children require a remifentanil infusion rate twofold higher than adults to block responses to skin incision. Similar data concerning remifentanil requirements are unavailable during total IV anesthesia. METHODS We prospectively determined the infusion rate (IR) of remifentanil necessary to block the somatic response to skin incision in 50% (IR50) of adults (n = 20, aged 20-60 yr) and children (n = 20, aged 3-11 yr) during propofol anesthesia. In each patient undergoing lower abdominal surgery, a remifentanil infusion was initiated, followed by target-controlled infusion of propofol set at a plasma concentration of 6 mug/mL. After tracheal intubation, propofol was reduced to 3 microg/mL until the end of the study. Remifentanil IR was determined according to Dixon's up-and-down method, with the first patient in each group receiving 0.2 microg x kg(-1) x min(-1) followed by the consecutive patient receiving 0.02 microg x kg(-1) x min(-1) modifications according to the response of the previous patient. The remifentanil IR was kept unchanged for at least 20 min before surgery. At the beginning of surgery, only the skin incision was performed, and the somatic response was observed. If there was any gross movement of extremity the response was considered positive. RESULTS The IR50 (CI(95%)) was 0.08 (0.06-0.12) microg x kg(-1) x min(-1) in adults and 0.15 (0.13-0.17) microg x kg(-1) x min(-1) in children (P < 0.001). CONCLUSION These results demonstrate that, similar to sevoflurane anesthesia, during total IV anesthesia with propofol, children require a remifentanil IR almost twofold higher than adults to block the somatic response to skin incision.
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Affiliation(s)
- Hernán R Muñoz
- Departamento de Anestesiología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
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17
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Muñoz HR, Cortínez LI, Ibacache ME, León PJ. Effect site concentrations of propofol producing hypnosis in children and adults: comparison using the bispectral index. Acta Anaesthesiol Scand 2006; 50:882-7. [PMID: 16879473 DOI: 10.1111/j.1399-6576.2006.01062.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
BACKGROUND No study has determined the concentration of propofol producing a degree of hypnosis compatible with anaesthesia in children. As a result, concentrations determined in adults are recommended for children. As this can result in an inadequate depth of anaesthesia, we determined the predicted effect site concentration (C(e)) of propofol necessary to obtain a bispectral index (BIS) of 50 in 50% (EC(e50)) of children and adults. METHODS Twenty adults (aged 33-44 years) and 20 children (aged 3-11 years) undergoing surgery under general anaesthesia were studied. All were monitored with a BIS monitor, and a target controlled infusion of propofol aiming for a constant C(e) value was started. After 10 min, patients were evaluated using a sedation scale, and the last 5 min was used to determine the mean BIS for this C(e) value. The C(e) value of propofol was defined using the up-and-down method of Dixon and Massey. The first patient in each group received C(e)= 6 microg/ml; thereafter, it was modified in 0.5 microg/ml decrements/increments with positive or negative responses, respectively. A positive response was BIS < 50 and a negative response was BIS > or = 50. The EC(e50) value was compared using unpaired Student's t-test. The prediction probability (P(K)) was used to study the association between BIS and the sedation score. RESULTS The mean EC(e50) (95% confidence interval) values were 3.75 microg/ml (2.97-4.75 microg/ml) in adults and 3.65 microg/ml (3.36-3.96 microg/ml) in children (not significant). All patients with BIS < 50 were unarousable with tactile stimulation. The P(K) value was 0.99 in both groups. CONCLUSIONS The predicted C(e) value of propofol resulting in BIS = 50 was similar in adults and children aged 3-11 years. The predicted C(e) value of propofol producing hypnosis in adults also seems to be useful in this paediatric population.
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Affiliation(s)
- H R Muñoz
- Departamento de Anestesiología, Pontificia Universidad Católica de Chile, Marcoleta 367, Santiago, Chile.
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18
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Abstract
PURPOSE OF REVIEW This review assesses whether there is a carbon dioxide concentration range that provides optimum benefit to the patient intraoperatively. It includes the physiological effects of carbon dioxide on various organ systems in awake and anesthetized individuals and its clinical effects in the ischemia/reperfusion setting. This review will present views on end-tidal or arterial carbon dioxide tension management in the perioperative period. RECENT FINDINGS Hypocapnia reduces intracranial pressure and is used by clinicians during acute traumatic brain injury, acute intracranial hemorrhage, and acutely growing brain tumors. There is mounting evidence, however, that hypercapnia improves tissue perfusion and oxygenation. Therefore, clinicians may want to induce mild-to-moderate hypercapnia during reperfusion states such as major vascular surgery, organ transplantation, tissue-graft surgery, and cases managed with low mean arterial pressures to control bleeding. As hypercapnia preserves cerebral blood flow even under relatively low perfusion pressures, it may be beneficial during global reperfusion scenarios. This hypothesis needs to be tested extensively before being considered for clinical applications. From a different perspective, current American Heart Association Guidelines recommend 12-15 breaths/min during cardiopulmonary resuscitation and stress the potential negative role of inadvertent hyperventilation on survival outcome. The importance of this concept is discussed briefly. SUMMARY Overall, the benefits of managing carbon dioxide concentration intraoperatively for the maintenance of cardiac output, tissue oxygenation, perfusion, intracranial pressure, and cerebrovascular reactivity are well defined.
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Affiliation(s)
- Ozan Akça
- Department of Anesthesiology and Perioperative Medicine, OUTCOMES RESEARCH Institute, University of Louisville, Kentucky 40202, USA.
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Affiliation(s)
- U R Jahn
- Department of Anaesthesiology and Intensive Care, Muenster University Hospital, Albert-Schweitzer-Strasse 3, 48129 Muenster, Germany.
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Barlow R, Karsli C, Luginbuehl I, Bissonnette B. Desflurane increases cerebral blood flow velocity when used for rapid emergence from propofol anesthesia in children. Can J Anaesth 2004; 51:824-8. [DOI: 10.1007/bf03018457] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Karsli C, Luginbuehl I, Bissonnette B. The Cerebrovascular Response to Hypocapnia in Children Receiving Propofol. Anesth Analg 2004; 99:1049-1052. [PMID: 15385348 DOI: 10.1213/01.ane.0000132778.84943.8d] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Hypocapnia is used to treat acute increases in intracranial pressure during neurosurgery. Cerebrovascular reactivity to carbon dioxide (CCO(2)R) is preserved above 35 mm Hg ETco(2) in children during propofol anesthesia; however, a plateau effect has been suggested below 35 mm Hg. To further delineate this phenomenon, we measured CCO(2)R by transcranial Doppler (TCD) sonography over small increments in ETco(2) in 27 healthy children. Anesthesia comprised a standardized propofol infusion and a caudal epidural block. A TCD probe was placed to measure middle cerebral artery blood flow velocity (V(mca)). ETco(2) was adjusted between 24 and 40 mm Hg at 1-2 mm Hg increments using an exogenous source of CO(2). There was an exponential relationship between ETco(2) and V(mca) above an ETco(2) value of 30 mm Hg (r = 0.82). However, V(mca) did not change with ETco(2) less than 30 mm Hg (r = 0.06). There were no significant changes in heart rate or arterial blood pressure. We conclude that when contemplating methods to decrease brain volume and intracranial pressure, hyperventilation to ETco(2) values less than 30 mm Hg may not be necessary in children receiving propofol, as no further reduction in cerebral blood flow velocity will be achieved.
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Affiliation(s)
- Cengiz Karsli
- From the Department of Anesthesia, The Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada
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Wilson-Smith E, Karsli C, Luginbuehl I, Bissonnette B. Effect of nitrous oxide on cerebrovascular reactivity to carbon dioxide in children during sevoflurane anaesthesia. Br J Anaesth 2003; 91:190-5. [PMID: 12878616 DOI: 10.1093/bja/aeg171] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Sevoflurane and nitrous oxide have intrinsic cerebral vasodilatory activity. To determine the effects of nitrous oxide on cerebrovascular reactivity to carbon dioxide (CCO(2)R) during sevoflurane anaesthesia in children, middle cerebral artery blood flow velocity (V(mca)) was measured over a range of end-tidal carbon dioxide concentrations (E'(CO(2))), using transcranial Doppler (TCD) ultrasonography. METHODS Ten children aged 1.5-6 yr were anaesthetized with sevoflurane and received a caudal block. Patients were allocated randomly to receive either air-nitrous oxide or nitrous oxide-air. Further randomization determined the sequence of E'(CO(2)) (25, 35, 45, and 55 mm Hg) and sevoflurane (1.0 then 1.5 MAC or 1.5 then 1.0 MAC) concentrations. Once steady state had been reached, three measurements of V(mca), mean arterial pressure (MAP), and heart rate (HR) were recorded. RESULTS Cerebrovascular carbon dioxide reactivity was reduced in the 25-35 mm Hg E'(CO(2)) range on the addition of nitrous oxide to 1.5 MAC, but not 1.0 MAC sevoflurane. A plateau in CCO(2)R of 0.4-0.6% per mm Hg was seen in all groups between E'(CO(2)) values of 45 and 55 mm Hg. Mean HR and MAP remained constant throughout the study period. CONCLUSIONS Cerebrovascular carbon dioxide reactivity is reduced at and above an E'(CO(2)) of 45 mm Hg during 1.0 and 1.5 MAC sevoflurane anaesthesia. The addition of nitrous oxide to 1.5 MAC sevoflurane diminishes CCO(2)R in the hypocapnic range. This should be taken into consideration when hyperventilation techniques for reduction of brain bulk are being contemplated in children with raised intracranial pressure.
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Affiliation(s)
- E Wilson-Smith
- Department of Anesthesia, The Hospital for Sick Children and the University of Toronto, 555 University Avenue, Toronto, ON M5G 1X8, Canada
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