Oxygenation during the apnoeic phase preceding intubation in adults in prehospital, emergency department, intensive care and operating theatre environments.

BACKGROUND: Apnoeic oxygenation is the delivery of oxygen during the apnoeic phase preceding intubation. It is used to prevent respiratory complications of endotracheal intubation that have the potential to lead to significant adverse events including dysrhythmia, haemodynamic decompensation, hypoxic brain injury and death. Oxygen delivered by nasal cannulae during the apnoeic phase of intubation (apnoeic oxygenation) may serve as a non-invasive adjunct to endotracheal intubation to decrease the incidence of hypoxaemia, morbidity and mortality. OBJECTIVES: To evaluate the benefits and harms of apnoeic oxygenation before intubation in adults in the prehospital, emergency department, intensive care unit and operating theatre environments compared to no apnoeic oxygenation during intubation. SEARCH METHODS: We used standard, extensive Cochrane search methods. The latest search date was 4 November 2022. SELECTION CRITERIA: We included randomized controlled trials (RCTs) and quasi-RCTs that compared the use of any form of apnoeic oxygenation including high flow and low flow nasal cannulae versus no apnoeic oxygenation during intubation. We defined quasi-randomization as participant allocation to each arm by means that were not truly random, such as alternation, case record number or date of birth. We excluded comparative prospective cohort and comparative retrospective cohort studies, physiological modelling studies and case reports. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were 1. hospital stay and 2. incidence of severe hypoxaemia. Our secondary outcomes were 3. incidence of hypoxaemia, 4. lowest recorded saturation of pulse oximetry (SpO2), 5. intensive care unit (ICU) stay, 6. first pass success rate, 7. adverse events and 8. MORTALITY: We used GRADE to assess certainty of evidence. MAIN RESULTS: We included 23 RCTs (2264 participants) in our analyses. Eight studies (729 participants) investigated the use of low-flow (15 L/minute or less), and 15 studies (1535 participants) investigated the use of high-flow (greater than 15 L/minute) oxygen. Settings were varied and included the emergency department (2 studies, 327 participants), ICU (7 studies, 913 participants) and operating theatre (14 studies, 1024 participants). We considered two studies to be at low risk of bias across all domains. None of the studies reported on hospital length of stay. In predominately critically ill people, there may be little to no difference in the incidence of severe hypoxaemia (SpO2 less than 80%) when using apnoeic oxygenation at any flow rate from the start of apnoea until successful intubation (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.66 to 1.11; P = 0.25, I² = 0%; 15 studies, 1802 participants; low-certainty evidence). There was insufficient evidence of any effect on the incidence of hypoxaemia (SpO2 less than 93%) (RR 0.58, 95% CI 0.23 to 1.46; P = 0.25, I² = 36%; 3 studies, 489 participants; low-certainty evidence). There may be an improvement in the lowest recorded oxygen saturation, with a mean increase of 1.9% (95% CI 0.75% to 3.05%; P < 0.001, I² = 86%; 15 studies, 1525 participants; low-certainty evidence). There may be a reduction in the duration of ICU stay with the use of apnoeic oxygenation during intubation (mean difference (MD) ‒1.13 days, 95% CI ‒1.51 to ‒0.74; P < 0.0001, I² = 46%; 5 studies, 815 participants; low-certainty evidence). There may be little to no difference in first pass success rate (RR 1.00, 95% CI 0.93 to 1.08; P = 0.79, I² = 0%; 8 studies, 826 participants; moderate-certainty evidence). There may be little to no difference in incidence of adverse events including oral trauma, arrhythmia, aspiration, hypotension, pneumonia and cardiac arrest when apnoeic oxygenation is used. There was insufficient evidence about any effect on mortality (RR 0.84, 95% CI 0.70 to 1.00; P = 0.06, I² = 0%; 6 studies, 1015 participants; low-certainty evidence). AUTHORS' CONCLUSIONS: There was some evidence that oxygenation during the apnoeic phase of intubation may improve the lowest recorded oxygen saturation. However, the differences in oxygen saturation were unlikely to be clinically significant. This did not translate into any measurable effect on the incidence of hypoxaemia or severe hypoxaemia in a group of predominately critically ill people. We were unable to assess the influence on hospital length of stay; however, there was a reduction in ICU stay in the apnoeic oxygenation group. The mechanism for this is unclear as there was little to no difference in first pass success or adverse event rates.

Comparison of Supraglottic Airway Devices With Endotracheal Intubation in Low-Risk Patients for Cesarean Delivery: Systematic Review and Meta-analysis.

BACKGROUND: The safety and adverse event rate of supraglottic airway (SGA) devices for cesarean delivery (CD) is poorly characterized. The primary aims of this review were to determine whether the first-pass success was higher and time to insertion for SGA was faster than endotracheal intubation for elective CD. The secondary aim was to determine the airway-related adverse event rate associated with SGA use compared to endotracheal intubation in elective CD under general anesthesia (GA). METHODS: Six databases were systematically searched until September 2019. Included studies reported on the use of SGA in comparison to endotracheal tube intubation. A comparative meta-analysis between SGA and endotracheal intubation was performed using RevMan 5.3 software. Dichotomous outcomes were reported using an odds ratio (OR) with 95% confidence interval (CI). The results for continuous outcomes were reported using a weighted mean difference (WMD) with 95% CI. RESULTS: Fourteen studies with 2236 patients compared SGA and endotracheal intubation. Overall, there was no statistically significant difference in first-attempt success rate (OR = 1.92; 95% CI, 0.85-4.32; I = 0%; P = .44). There was no clinically significant difference in time to insertion (WMD = -15.80 seconds; 95% CI, -25.30 to -6.31 seconds; I= 100%; P = .001). Similarly, there was no difference in any adverse event rate except sore throat which was reduced with the use of an SGA (OR = 0.16; 95% CI, 0.08-0.32; I= 53%; P < .001). CONCLUSIONS: Despite the reasonable insertion success rate and safety profile of SGAs demonstrated in this meta-analysis, the analysis remains underpowered and therefore inconclusive. At present, further studies are required before the use of an SGA as the first-line airway for an elective CD can be recommended.

Antiarrhythmics in Cardiac Arrest: A Systematic Review and Meta-Analysis.

INTRODUCTION: It is widely accepted that antiarrhythmics play a role in cardiopulmonary resuscitation (CPR) universally, but the absolute benefit of antiarrhythmic use and the drug of choice in advanced life support remains controversial. AIM: To perform a thorough, in-depth review and analysis of current literature to assess the efficacy of antiarrhythmics in advanced life support. MATERIAL AND METHODS: Two authors systematically searched through multiple bibliographic databases including CINAHL, SCOPUS, PubMed, Web of Science, Medline(Ovid) and the Cochrane Clinical Trials Registry. To be included studies had to compare an antiarrhythmic to either a control group, placebo or another antiarrhythmic in adult cardiac arrests. These studies were independently screened for outcomes in cardiac arrest assessing the effect of antiarrhythmics on return of spontaneous circulation (ROSC), survival and neurological outcomes. Data was extracted independently, compared for homogeneity and level of evidence was evaluated using the Cochrane Collaboration's tool for assessing the risk of bias. The Mantel-Haenszel (M-H) random effects model was used and heterogeneity was assessed using the I2 statistic. RESULTS AND DISCUSSION: The search of the literature yielded 30 studies, including 39,914 patients. Eight antiarrhythmic agents were identified. Amiodarone and lidocaine, the two most commonly used agents, showed no significant effect on any outcome either against placebo or each other. Small low quality studies showed benefits in isolated outcomes with esmolol and bretylium against placebo. The only significant benefit of one antiarrhythmic over another was demonstrated with nifekalant over lidocaine for survival to admission (p=0.003). On sensitivity analysis of a small number of high quality level one RCTs, both amiodarone and lidocaine had a significant increase in survival to admission, with no effect on survival to discharge. CONCLUSIONS: This systematic review and meta-analysis suggests that, based on current literature and data, there has been no conclusive evidence that any antiarrhythmic agents improve rates of ROSC, survival to admission, survival to discharge or neurological outcomes. Given the side effects of some of these agents, we recommend further research into their utility in current cardiopulmonary resuscitation guidelines.

Apnoeic oxygenation during intubation in the intensive care unit: A systematic review and meta-analysis.

Hypoxaemia increases the risk of cardiac arrest and mortality during intubation. The reduced physiological reserve and reduced efficacy of pre-oxygenation in intensive care patients makes their intubation particularly dangerous. Apnoeic oxygenation is a promising means of preventing hypoxaemia in this setting. We sought to ascertain whether apnoeic oxygenation reduces the incidence of hypoxaemia when used during endotracheal intubation in the intensive care unit (ICU). A systematic review of five databases for all relevant studies published up to November 2016 was performed. Eligible studies investigated apnoeic oxygenation during intubation in the ICU, irrespective of design. All studies were assessed for risk of bias and level of evidence. A meta-analysis was performed on all data using Revman 5.3. Six studies including 518 patients were retrieved. The study found level 1 evidence of a significant reduction in the incidence of critical desaturation (RR = 0.69, CI = 0.48-1.00, p = 0.05) and a significant increase in the lowest SpO2 value by 2.83% (CI = 2.28-3.38, p < 0.00001). There was a significant reduction in ICU stay (WMD = -2.89, 95%CI = -3.25 to -2.51, p < 0.00001). There was no significant difference between groups regarding mortality (RR = 0.77, 95%CI = 0.59-1.03, p = 0.08), first pass intubation success (RR = 1.17, 95%CI = 0.67 to 2.03, p = 0.58), arrhythmia during intubation (RR = 0.58, 95%CI = 0.08 to 4.29, p = 0.60), cardiac arrest during intubation (RR = 0.33, 95%CI = 0.01 to 7.84, p = 0.49) and duration of ventilation (WMD = -1.97, 95%CI = -5.89 to 1.95, p = 0.32). Apnoeic oxygenation reduces patient hypoxaemia during intubation performed in the ICU. This meta-analysis found evidence that apnoeic oxygenation may significantly reduce the incidence of critical desaturation and significantly raises the minimum recorded SpO2 in this setting. We recommend apnoeic oxygenation be incorporated into ICU intubation protocol.

Apneic oxygenation during intubation in the emergency department and during retrieval: A systematic review and meta-analysis.

BACKGROUND: Hypoxemia increases the risk of intubation markedly. Such concerns are multiplied in the emergency department (ED) and during retrieval where patients may be unstable, preparation or preoxygenation time limited and the environment uncontrolled. Apneic oxygenation is a promising means of preventing hypoxemia in this setting. AIM: To test the hypothesis that apnoeic oxygenation reduces the incidence of hypoxemia during endotracheal intubation in the ED and during retrieval. METHODS: We undertook a systematic review of six databases for all relevant studies published up to November 2016. Included studies evaluated apneic oxygenation during intubation in the ED and during retrieval. There were no exemptions based on study design. All studies were assessed for level of evidence and risk of bias. The Review Manager 5.3 software was used to perform meta-analysis of the pooled data. RESULTS: Six trials and a total 1822 cases were included for analysis. The study found a significant reduction in the incidence of desaturation (RR=0.76, p=0.002) and critical desaturation (RR=0.51, p=0.01) when apneic oxygenation was implemented. There was also a significant improvement in first pass intubation success rate (RR=1.09, p=0.004). CONCLUSION: Apneic oxygenation may reduce patient hypoxemia during intubation performed in the ED and during retrieval. It also improves intubation first-pass success rate in this setting.

Intubation using apnoeic oxygenation to prevent desaturation: A systematic review and meta-analysis.

PURPOSE: To determine whether or not apnoeic oxygenation reduces the incidence of hypoxaemia during endotracheal intubation. MATERIALS AND METHODS: A systematic search of six databases for all relevant studies until November 2016 was performed. All study designs using apnoeic oxygenation during intubation were eligible for inclusion. All studies were assessed for level of evidence and risk of bias. A meta-analysis was performed on all data using Revman 5.3. RESULTS: Seventeen studies including 2422 patients were retrieved. Overall there was a significant reduction in the incidence of desaturation (RR=0.65; p<0.00001), critical desaturation (RR=0.61, p=0.002) and safe apnoea time (WMD=1.73min, p<0.00001). There was no significant difference in mortality (RR=0.77, p=0.08). CONCLUSIONS: In patients whom are being intubated for any indication other than respiratory failure, apnoeic oxygenation at any flow rate 15L or greater is likely to reduce their incidence of desaturation (<90%) and critical desaturation (<80%). However, further high quality RCTs are required given the high degree of heterogeneity in many of the outcomes and subgroup analyses.

Optimal wrist positioning for radial arterial cannulation in adults: A systematic review and meta-analysis.

BACKGROUND: Wrist extension is commonly taught as part of the radial artery cannulation technique. Currently the degree of wrist extension required to optimize cannulation success remains inconclusive. This is the first meta-analysis to investigate optimal wrist positioning for radial artery cannulation. METHODS: Five major databases (CINAHL, SCOPUS, PubMed, Medline and Web of Science) were systematically searched until June 2016. All studies were assessed for level of evidence and risk of bias. The data for each outcome was then assessed via a meta-analysis. RESULTS: Five studies including 500 patients were found. There is moderate evidence to support 45° wrist angulation for improved radial artery cannulation. Radial arterial height is likely to be increased at 45°, cannulation time is significantly faster and success rates are likely higher than at other degrees of angulation. However, this evidence is confounded by the significant heterogeneity (I2 >75%) which is at least in part related to a high proportion of healthy young volunteers who were amongst the studied populations. CONCLUSION: This review found moderate evidence in support of a 45° wrist angulation to facilitate arterial cannulation, however the results are largely limited by the external validity of the data collected given the restrictive populations studied. Any further studies investigating the effect of altering wrist angulation on radial artery cannulation should focus on populations who are either likely to require arterial cannulation or predisposed to difficult access.