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Ille A, Nilsson C, Sjödin C, Daham S, Persson P, Svensson CJ. Airway pressure release ventilation (APRV) versus pressure support ventilation (PSV)-A prospective intervention trial comparing haemodynamic parameters in intensive care patients. Acta Anaesthesiol Scand 2024. [PMID: 38764089 DOI: 10.1111/aas.14434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 05/21/2024]
Abstract
BACKGROUND AND AIM Assisted mechanical ventilation may alter the pressure profile in the thorax compared to normal breathing, which can affect the blood flow to and from the heart. Studies suggest that in patients with severe lung disease, airway pressure release ventilation (APRV) may be haemodynamically beneficial compared to other ventilator settings. The primary aim of this study was to investigate if APRV affects cardiac index in intubated intensive care patients without severe lung disease when compared to pressure support ventilation (PSV). The secondary aim comprised potential changes in other haemodynamic and ventilatory parameters. METHODS Twenty patients were enrolled in the intensive care unit (ICU) at Sahlgrenska University Hospital. Eligible patients met the inclusion criteria; 18 years of age or above, intubated and mechanically ventilated, triggering and stable on PSV mode, with indwelling haemodynamic monitoring via a pulse-induced continuous cardiac output (PiCCO) catheter. The study protocol started with a 30-min interval on PSV mode, followed by a 30-min interval on APRV mode, and finally a 30-min interval back on PSV mode. At the end of each interval, PiCCO outputs, ventilator outputs, arterial and venous blood gas analyses, heart rate and central venous pressure were recorded and compared between modes. RESULTS There was no significant difference in cardiac index (3.42 vs. 3.39 L/min/m2) between PSV and APRV, but a significant increase in central venous pressure (+1.0 mmHg, p = .027). Furthermore, we found a significant reduction in peak airway pressure (-3.16 cmH2O, p < .01) and an increase in mean airway pressure (+2.1 cmH2O, p < .01). No statistically significant change was found in oxygenation index (partial pressure of O2 [pO2]/fraction of inspired oxygen) nor in other secondary outcomes when comparing PSV and APRV. There was no significant association between global end-diastolic volume index and cardiac index (R2 = 0.0089) or central venous pressure (R2 = 0.278). All parameters returned to baseline after switching the ventilator mode back to PSV. CONCLUSION We could not detect any changes in cardiac index in ICU patients without severe lung disease during APRV compared to PSV mode, despite lower peak airway pressure and increased mean airway pressure.
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Affiliation(s)
- Alexandru Ille
- Department of Anaesthesiology and Intensive Care, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Carl Nilsson
- Department of Anaesthesiology and Intensive Care, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Carl Sjödin
- Department of Anaesthesiology and Intensive Care, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Shanay Daham
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Per Persson
- Department of Anaesthesiology and Intensive Care, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
- Department of Anaesthesiology and Intensive Care Medicine, Institute of Clinical Sciences at the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Carl Johan Svensson
- Department of Anaesthesiology and Intensive Care, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
- Department of Anaesthesiology and Intensive Care Medicine, Institute of Clinical Sciences at the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Naendrup JH, Steinke J, Garcia Borrega J, Stoll SE, Michelsen PO, Assion Y, Shimabukuro-Vornhagen A, Eichenauer DA, Kochanek M, Böll B. Airway Pressure Release Ventilation in COVID-19-Associated Acute Respiratory Distress Syndrome-A Multicenter Propensity Score-Matched Analysis. J Intensive Care Med 2024; 39:84-93. [PMID: 37861125 DOI: 10.1177/08850666231207303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Background: There are limited and partially contradictory data on the effects of airway pressure release ventilation (APRV) in COVID-19-associated acute respiratory distress syndrome (CARDS). Therefore, we analyzed the clinical outcome, complications, and longitudinal course of ventilation parameters and laboratory values in patients with CARDS, who were mechanically ventilated using APRV. Methods: Respective data from 4 intensive care units (ICUs) were collected and compared to a matched cohort of patients receiving conventional low tidal volume ventilation (LTV). Propensity score matching was performed based on age, sex, blood gas analysis, and APACHE II score at admission, as well as the implementation of prone positioning. Findings: Forty patients with CARDS, who were mechanically ventilated using APRV, and 40 patients receiving LTV were matched. No significant differences were detected for tidal volumes per predicted body weight, peak pressure values, and blood gas analyses on admission, 6 h post admission as well as on day 3 and day 7. Regarding ICU survival, no significant difference was identified between APRV patients (40%) and LTV patients (42%). Median duration of mechanical ventilation and duration of ICU treatment were comparable in both groups. Similar complication rates with respect to ventilator-associated pneumonia, septic shock, thromboembolic events, barotrauma, as well as the necessity for hemodialysis were detected for both groups. Clinical characteristics that were associated with increased mortality in a Cox proportional hazards regression analysis included age (hazard ratio [HR] 1.08, 95% confidence interval [CI] 1.04-1.1; P < .001), severe acute respiratory distress syndrome (HR 2.62, 95% CI 1.02-6.7; P = .046) and the occurrence of septic shock (HR 17.18, 95% CI 2.06-143.2; P = .009), but not the ventilation mode. Interpretation: Intensive care unit survival, duration of mechanical ventilation, and ICU treatment as well as ventilation-associated complication rates were equivalent using APRV compared to conventional LTV in patients with CARDS.
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Affiliation(s)
- Jan-Hendrik Naendrup
- Faculty of Medicine and University Hospital Cologne, First Department of Internal Medicine, University of Cologne, Cologne, Germany
- Center for Integrated Oncology Aachen Bonn Cologne Dusseldorf (CIO), Cologne, Germany
| | - Jonathan Steinke
- Faculty of Medicine and University Hospital Cologne, First Department of Internal Medicine, University of Cologne, Cologne, Germany
- Center for Integrated Oncology Aachen Bonn Cologne Dusseldorf (CIO), Cologne, Germany
| | - Jorge Garcia Borrega
- Faculty of Medicine and University Hospital Cologne, First Department of Internal Medicine, University of Cologne, Cologne, Germany
- Center for Integrated Oncology Aachen Bonn Cologne Dusseldorf (CIO), Cologne, Germany
| | - Sandra Emily Stoll
- Faculty of Medicine and University Hospital Cologne, Department of Anaesthesiology and Intensive Care Medicine, University of Cologne, Cologne, Germany
| | - Per Ole Michelsen
- Department of Anaesthesiology, Intensive Care Medicine and Pain Therapy, St. Vinzenz Hospital Cologne, Cologne, Germany
| | - Yannick Assion
- Department of Anaesthesiology, Intensive Care Medicine and Pain Therapy, Porz am Rhein Hospital Cologne, Cologne, Germany
| | - Alexander Shimabukuro-Vornhagen
- Faculty of Medicine and University Hospital Cologne, First Department of Internal Medicine, University of Cologne, Cologne, Germany
- Center for Integrated Oncology Aachen Bonn Cologne Dusseldorf (CIO), Cologne, Germany
| | - Dennis Alexander Eichenauer
- Faculty of Medicine and University Hospital Cologne, First Department of Internal Medicine, University of Cologne, Cologne, Germany
- Center for Integrated Oncology Aachen Bonn Cologne Dusseldorf (CIO), Cologne, Germany
| | - Matthias Kochanek
- Faculty of Medicine and University Hospital Cologne, First Department of Internal Medicine, University of Cologne, Cologne, Germany
- Center for Integrated Oncology Aachen Bonn Cologne Dusseldorf (CIO), Cologne, Germany
| | - Boris Böll
- Faculty of Medicine and University Hospital Cologne, First Department of Internal Medicine, University of Cologne, Cologne, Germany
- Center for Integrated Oncology Aachen Bonn Cologne Dusseldorf (CIO), Cologne, Germany
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Cruz AF, Herrmann J, Ramcharran H, Kollisch-Singule M, Tawhai MH, Bates JHT, Nieman GF, Kaczka DW. Sustained vs. Intratidal Recruitment in the Injured Lung During Airway Pressure Release Ventilation: A Computational Modeling Perspective. Mil Med 2023; 188:141-148. [PMID: 37948236 DOI: 10.1093/milmed/usad059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 02/03/2023] [Accepted: 02/14/2023] [Indexed: 11/12/2023] Open
Abstract
INTRODUCTION During mechanical ventilation, cyclic recruitment and derecruitment (R/D) of alveoli result in focal points of heterogeneous stress throughout the lung. In the acutely injured lung, the rates at which alveoli can be recruited or derecruited may also be altered, requiring longer times at higher pressure levels to be recruited during inspiration, but shorter times at lower pressure levels to minimize collapse during exhalation. In this study, we used a computational model to simulate the effects of airway pressure release ventilation (APRV) on acinar recruitment, with varying inspiratory pressure levels and durations of exhalation. MATERIALS AND METHODS The computational model consisted of a ventilator pressure source, a distensible breathing circuit, an endotracheal tube, and a porcine lung consisting of recruited and derecruited zones, as well as a transitional zone capable of intratidal R/D. Lung injury was simulated by modifying each acinus with an inflation-dependent surface tension. APRV was simulated for an inhalation duration (Thigh) of 4.0 seconds, inspiratory pressures (Phigh) of 28 and 40 cmH2O, and exhalation durations (Tlow) ranging from 0.2 to 1.5 seconds. RESULTS Both sustained acinar recruitment and intratidal R/D within the subtree were consistently higher for Phigh of 40 cmH2O vs. 28 cmH2O, regardless of Tlow. Increasing Tlow was associated with decreasing sustained acinar recruitment, but increasing intratidal R/D, within the subtree. Increasing Tlow was associated with decreasing elastance of both the total respiratory system and transitional subtree of the model. CONCLUSIONS Our computational model demonstrates the confounding effects of cyclic R/D, sustained recruitment, and parenchymal strain stiffening on estimates of total lung elastance during APRV. Increasing inspiratory pressures leads to not only more sustained recruitment of unstable acini but also more intratidal R/D. Our model indicates that higher inspiratory pressures should be used in conjunction with shorter exhalation times, to avoid increasing intratidal R/D.
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Affiliation(s)
- Andrea F Cruz
- Department of Anesthesia, University of Iowa, Iowa City, IA 52242, USA
| | - Jacob Herrmann
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Harry Ramcharran
- Department of Surgery, SUNY Upstate Medical Center, Syracuse, NY 13210, USA
| | | | - Merryn H Tawhai
- Department of Bioengineering, University of Auckland, Auckland 1124, New Zealand
| | - Jason H T Bates
- Department of Medicine, University of Vermont, Burlington, VT 05405, USA
| | - Gary F Nieman
- Department of Surgery, SUNY Upstate Medical Center, Syracuse, NY 13210, USA
| | - David W Kaczka
- Department of Anesthesia, University of Iowa, Iowa City, IA 52242, USA
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
- Department of Radiology, University of Iowa, Iowa City, IA 52242, USA
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Essex K, Mullen J, Lauria MJ, Braude DA. Management of Hantavirus Cardiopulmonary Syndrome in Critical Care Transport: A Review. Air Med J 2023; 42:483-487. [PMID: 37996187 DOI: 10.1016/j.amj.2023.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 07/19/2023] [Accepted: 07/31/2023] [Indexed: 11/25/2023]
Abstract
In 1993, the Southwest found itself staring down a disease then known as "unexplained adult respiratory syndrome." During the outbreak, 12 of 23 known patients died. What we now recognize as hantavirus cardiopulmonary syndrome still remains a rare and deadly disease. Although no cure exists, modern supportive techniques such as extracorporeal membrane oxygenation have increased survival among these patients. Early diagnosis has become the primary factor in patient survival. The initial presentation of hantavirus is similar to acute respiratory distress syndrome, necessitating a high index of suspicion to afford the patient the best chance of survival. Diagnosis is further complicated by prolonged and nonspecific incubation periods making it difficult to pinpoint an exposure. Familiarizing oneself with common clinical presentations, diagnostic strategies, and testing is the best way to increase patient survival. Because hantavirus has a predilection for rural areas, transport to a tertiary facility is paramount to provide the resources necessary to care for these complex patients. Rapid sequence intubation, although common in airway-compromised patients, could prove fatal in the setting of the severe hemodynamic instability found in hantavirus cardiopulmonary syndrome. Anticipation of significant pressor use and fluid administration could likely mean the difference in patient mortality during transport.
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Affiliation(s)
- Kyle Essex
- AIT Airmed, Albuquerque, New Mexico; American Medical Response, Las Cruces, New Mexico.
| | | | - Michael J Lauria
- Department of Emergency Medicine, University of New Mexico School of Medicine, Albuquerque, NM; Lifeguard Air Emergency Services, Albuquerque, NM
| | - Darren A Braude
- Department of Emergency Medicine, University of New Mexico School of Medicine, Albuquerque, NM; Lifeguard Air Emergency Services, Albuquerque, NM
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Briones-Claudett KH, Freire AX. Safety of Fiberoptic Bronchoscopy in Airway Pressure Release Ventilation Mode in Critically Ill Patients: Are These Results Safe? THORACIC RESEARCH AND PRACTICE 2023; 24:282-283. [PMID: 37581378 PMCID: PMC10544180 DOI: 10.5152/thoracrespract.2023.22214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 04/12/2023] [Indexed: 08/16/2023]
Affiliation(s)
- Killen H. Briones-Claudett
- Universidad de Las Americas Facultad de Medicina, Quito, Ecuador
- Intensive Care Unit, Ecuadorian Institute of Social Security (IESS), Babahoyo, Ecuador
| | - Amado X. Freire
- Division of Pulmonary, Critical Care, and Sleep Medicine, The University of Tennessee Health Science Center, Memphis, USA
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Akoumianaki E, Bolaki M, Prinianakis G, Konstantinou I, Panagiotarakou M, Vaporidi K, Georgopoulos D, Kondili E. Hiccup-like Contractions in Mechanically Ventilated Patients: Individualized Treatment Guided by Transpulmonary Pressure. J Pers Med 2023; 13:984. [PMID: 37373973 DOI: 10.3390/jpm13060984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/05/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
Hiccups-like contractions, including hiccups, respiratory myoclonus, and diaphragmatic tremor, refer to involuntary, spasmodic, and inspiratory muscle contractions. They have been repeatedly described in mechanically ventilated patients, especially those with central nervous damage. Nevertheless, their effects on patient-ventilator interaction are largely unknown, and even more overlooked is their contribution to lung and diaphragm injury. We describe, for the first time, how the management of hiccup-like contractions was individualized based on esophageal and transpulmonary pressure measurements in three mechanically ventilated patients. The necessity or not of intervention was determined by the effects of these contractions on arterial blood gases, patient-ventilator synchrony, and lung stress. In addition, esophageal pressure permitted the titration of ventilator settings in a patient with hypoxemia and atelectasis secondary to hiccups and in whom sedatives failed to eliminate the contractions and muscle relaxants were contraindicated. This report highlights the importance of esophageal pressure monitoring in the clinical decision making of hiccup-like contractions in mechanically ventilated patients.
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Affiliation(s)
- Evangelia Akoumianaki
- Department of Intensive Care Unit, University Hospital of Heraklion, 71110 Crete, Greece
- School of Medicine, University of Crete, 71003 Heraklion, Greece
| | - Maria Bolaki
- Department of Intensive Care Unit, University Hospital of Heraklion, 71110 Crete, Greece
| | - Georgios Prinianakis
- Department of Intensive Care Unit, University Hospital of Heraklion, 71110 Crete, Greece
| | - Ioannis Konstantinou
- Department of Intensive Care Unit, University Hospital of Heraklion, 71110 Crete, Greece
| | - Meropi Panagiotarakou
- Department of Intensive Care Unit, University Hospital of Heraklion, 71110 Crete, Greece
| | - Katerina Vaporidi
- Department of Intensive Care Unit, University Hospital of Heraklion, 71110 Crete, Greece
- School of Medicine, University of Crete, 71003 Heraklion, Greece
| | | | - Eumorfia Kondili
- Department of Intensive Care Unit, University Hospital of Heraklion, 71110 Crete, Greece
- School of Medicine, University of Crete, 71003 Heraklion, Greece
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Ding B, Xu F, Wang J, Pan C, Pang J, Chen Y, Li K. Design and evaluation of portable emergency ventilator prototype with novel titration methods. Biomed Signal Process Control 2023. [DOI: 10.1016/j.bspc.2023.104619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Acute Respiratory Distress Syndrome, Mechanical Ventilation, and Inhalation Injury in Burn Patients. Surg Clin North Am 2023; 103:439-451. [PMID: 37149380 PMCID: PMC10028407 DOI: 10.1016/j.suc.2023.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
Respiratory failure occurs with some frequency in seriously burned patients, driven by a combination of inflammatory and infection factors. Inhalation injury contributes to respiratory failure in some burn patients via direct mucosal injury and indirect inflammation. In burn patients, respiratory failure leading to acute respiratory distress syndrome, with or without inhalation injury, is effectively managed using principles evolved for non-burn critically ill patients.
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Spontaneous Breathing and Pendelluft in Patients with Acute Lung Injury: A Narrative Review. J Clin Med 2022; 11:jcm11247449. [PMID: 36556064 PMCID: PMC9783194 DOI: 10.3390/jcm11247449] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/10/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Acute respiratory distress syndrome (ARDS) is characterized by acute-onset rapid-deteriorating inflammatory lung injury. Although the preservation of spontaneous breathing may have physiological benefits in oxygenation, increasing evidence shows that vigorous spontaneous breathing may aggravate lung injury (i.e., patient self-inflicted lung injury). Increased lung stress and pendelluft, which is defined as intrapulmonary gas redistribution without a significant change in tidal volume, are important mechanisms of patient self-inflicted lung injury. The presence of pendelluft may be considered a surrogate marker of vigorous inspiratory effort, which can cause the dependent lung to overstretch. In this review, we summarized three major methods for electrical impedance tomography-based pendelluft monitoring. Future studies are warranted to compare and validate the different methods of pendelluft estimation in patients with ARDS.
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The optimal management of the patient with COVID‐19 pneumonia: HFNC, NIV/CPAP or mechanical ventilation? Afr J Thorac Crit Care Med 2022; 28. [DOI: 10.7196/ajtccm.2022.v28i3.241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2022] [Indexed: 11/07/2022] Open
Abstract
The recent pandemic has seen unprecedented demand for respiratory support of patients with COVID‐19 pneumonia, stretching services and clinicians. Yet despite the global numbers of patients treated, guidance is not clear on the correct choice of modality or the timing of escalation of therapy for an individual patient.This narrative review assesses the available literature on the best use of different modalities of respiratory support for an individual patient, and discusses benefits and risks of each, coupled with practical advice to improve outcomes.
On current data, in an ideal context, it appears that as disease severity worsens, conventional oxygen therapy is not sufficient alone. In more severe disease, i.e. PaO2/FiO2 ratios below approximately 200, helmet‐CPAP (continuous positive airway pressure) (although not widely available) may be superior to high‐flow nasal cannula (HFNC) therapy or facemask non‐invasive ventilation (NIV)/CPAP, and that facemask NIV/CPAP may be superior to HFNC, but with noted important complications, including risk of pneumothoraces.
In an ideal context, invasive mechanical ventilation should not be delayed where indicated and available. Vitally, the choice of respiratory support should not be prescriptive but contextualised to each setting, as supply and demand of resources vary markedly between institutions. Over time, institutions should develop clear policies to guide clinicians before demand exceeds supply, and should frequently review best practice as evidence matures.
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11
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Acute respiratory distress syndrome. JAAPA 2022; 35:29-33. [DOI: 10.1097/01.jaa.0000823164.50706.27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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12
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Use of Airway Pressure Release Ventilation in Patients With Acute Respiratory Failure Due to COVID-19: Results of a Single-Center Randomized Controlled Trial. Crit Care Med 2022; 50:586-594. [PMID: 34593706 PMCID: PMC8923279 DOI: 10.1097/ccm.0000000000005312] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVES Airway pressure release ventilation is a ventilatory mode characterized by a mandatory inverse inspiratory:expiratory ratio with a very short expiratory phase, aimed to avoid derecruitment and allow spontaneous breathing. Recent basic and clinical evidence suggests that this mode could be associated with improved outcomes in patients with acute respiratory distress syndrome. The aim of this study was to compare the outcomes between airway pressure release ventilation and traditional ventilation targeting low tidal volume, in patients with severe coronavirus disease 2019. DESIGN Single-center randomized controlled trial. SETTING ICU of a Mexican referral center dedicated to care of patients with confirmed diagnosis of coronavirus disease 2019. PATIENTS Ninety adult intubated patients with acute respiratory distress syndrome associated with severe coronavirus disease 2019. INTERVENTIONS Within 48 hours after intubation, patients were randomized to either receive ventilatory management with airway pressure release ventilation or continue low tidal volume ventilation. MEASUREMENTS AND MAIN RESULTS Forty-five patients in airway pressure release ventilation group and 45 in the low tidal volume group were included. Ventilator-free days were 3.7 (0-15) and 5.2 (0-19) in the airway pressure release ventilation and low tidal volume groups, respectively (p = 0.28). During the first 7 days, patients in airway pressure release ventilation had a higher Pao2/Fio2 (mean difference, 26 [95%CI, 13-38]; p < 0.001) and static compliance (mean difference, 3.7 mL/cm H2O [95% CI, 0.2-7.2]; p = 0.03), higher mean airway pressure (mean difference, 3.1 cm H2O [95% CI, 2.1-4.1]; p < 0.001), and higher tidal volume (mean difference, 0.76 mL/kg/predicted body weight [95% CI, 0.5-1.0]; p < 0.001). More patients in airway pressure release ventilation had transient severe hypercapnia, defined as an elevation of Pco2 at greater than or equal to 55 along with a pH less than 7.15 (42% vs 15%; p = 0.009); other outcomes were similar. Overall mortality was 69%, with no difference between the groups (78% in airway pressure release ventilation vs 60% in low tidal volume; p = 0.07). CONCLUSIONS In conclusion, when compared with low tidal volume, airway pressure release ventilation was not associated with more ventilator-free days or improvement in other relevant outcomes in patients with severe coronavirus disease 2019.
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Madekurozwa M, Bonneuil WV, Frattolin J, Watson DJ, Moore AC, Stevens MM, Moore J, Mathiszig-Lee J, van Batenburg-Sherwood J. A Novel Ventilator Design for COVID-19 and Resource-Limited Settings. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 3:707826. [PMID: 35047946 PMCID: PMC8757831 DOI: 10.3389/fmedt.2021.707826] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 09/07/2021] [Indexed: 11/13/2022] Open
Abstract
There has existed a severe ventilator deficit in much of the world for many years, due in part to the high cost and complexity of traditional ICU ventilators. This was highlighted and exacerbated by the emergence of the COVID-19 pandemic, during which the increase in ventilator production rapidly overran the global supply chains for components. In response, we propose a new approach to ventilator design that meets the performance requirements for COVID-19 patients, while using components that minimise interference with the existing ventilator supply chains. The majority of current ventilator designs use proportional valves and flow sensors, which remain in short supply over a year into the pandemic. In the proposed design, the core components are on-off valves. Unlike proportional valves, on-off valves are widely available, but accurate control of ventilation using on-off valves is not straightforward. Our proposed solution combines four on-off valves, a two-litre reservoir, an oxygen sensor and two pressure sensors. Benchtop testing of a prototype was performed with a commercially available flow analyser and test lungs. We investigated the accuracy and precision of the prototype using both compressed gas supplies and a portable oxygen concentrator, and demonstrated the long-term durability over 15 days. The precision and accuracy of ventilation parameters were within the ranges specified in international guidelines in all tests. A numerical model of the system was developed and validated against experimental data. The model was used to determine usable ranges of valve flow coefficients to increase supply chain flexibility. This new design provides the performance necessary for the majority of patients that require ventilation. Applications include COVID-19 as well as pneumonia, influenza, and tuberculosis, which remain major causes of mortality in low and middle income countries. The robustness, energy efficiency, ease of maintenance, price and availability of on-off valves are all advantageous over proportional valves. As a result, the proposed ventilator design will cost significantly less to manufacture and maintain than current market designs and has the potential to increase global ventilator availability.
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Affiliation(s)
- Michael Madekurozwa
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Willy V Bonneuil
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Jennifer Frattolin
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Daniel J Watson
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Axel C Moore
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
| | - Molly M Stevens
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
| | - James Moore
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Jakob Mathiszig-Lee
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom.,Department of Anaesthetics and Perioperative Medicine, Royal Marsden Hospital, London, United Kingdom
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