Apneic Oxygenation for Intubation in the Critically Ill. Let's Not Give Up!

Use of nasal high flow oxygen during acute respiratory failure

Nasal high flow (NHF) has gained popularity among intensivists to manage patients with acute respiratory failure. An important literature has accompanied this evolution. In this review, an international panel of experts assessed potential benefits of NHF in different areas of acute respiratory failure management. Analyses of the physiological effects of NHF indicate flow-dependent improvement in various respiratory function parameters. These beneficial effects allow some patients with severe acute hypoxemic respiratory failure to avoid intubation and improve their outcome. They require close monitoring to not delay intubation. Such a delay may worsen outcome. The ROX index may help clinicians decide when to intubate. In immunocompromised patients, NHF reduces the need for intubation but does not impact mortality. Beneficial physiological effects of NHF have also been reported in patients with chronic respiratory failure, suggesting a possible indication in acute hypercapnic respiratory failure. When intubation is required, NHF can be used to pre-oxygenate patients either alone or in combination with non-invasive ventilation (NIV). Similarly, NHF reduces reintubation alone in low-risk patients and in combination with NIV in high-risk patients. NHF may be used in the emergency department in patients who would not be offered intubation and can be better tolerated than NIV.

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.

Apnoeic oxygenation during intubation: a systematic review and meta-analysis

Apnoeic oxygenation during intubation is used to prevent desaturation during intubation. The aim of this review was to assess whether apnoeic oxygenation during endotracheal intubation reduced the incidence of hypoxaemia. Five major databases were systematically searched for all relevant studies published up to May 2016. All study designs with a control group and a group receiving apnoeic oxygenation were included in this review. These studies were then assessed for level of evidence and risk of bias. The data were then analysed using a meta-analysis. Eleven studies (six high quality randomised controlled trials, four low quality level two studies and one low quality level three study) were found. In the meta-analysis there was strong evidence for benefit of apnoeic oxygenation in terms of improved SpO₂ in elective surgical patients, obese patients and those undergoing emergency intubation without respiratory failure. However, no significant benefit was found in patients with respiratory failure. This is the first meta-analysis to be performed on apnoeic oxygenation during intubation. Apnoeic oxygenation provides significant benefit in terms of improving SpO₂ for the majority of intubations, although there appears to be no benefit in patients whose indication for intubation is respiratory failure. Apnoeic oxygenation ought to be considered for integration into intubation protocols.

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.

Apnoeic oxygenation via high-flow nasal cannula oxygen combined with non-invasive ventilation preoxygenation for intubation in hypoxaemic patients in the intensive care unit: the single-centre, blinded, randomised controlled OPTINIV trial

PURPOSE

High-flow nasal cannula oxygen (HFNC) has the potential to provide apnoeic oxygenation. We decided to assess in a proof-of-concept study whether the addition of HFNC to non-invasive ventilation (NIV) could reduce oxygen desaturation during intubation, compared with NIV alone for preoxygenation, in severely hypoxaemic intensive care unit (ICU) patients with respiratory failure.

METHODS

We conducted a randomised, controlled, single-centre trial with assessor-blinded outcome assessment in patients admitted to the ICU. Hypoxaemic patients requiring orotracheal intubation for respiratory failure were randomised to receive preoxygenation using HFNC [flow = 60 L/min, fraction of inspired oxygen (FiO2) = 100 %] combined with NIV (pressure support = 10 cmH2O, positive end-expiratory pressure = 5 cmH2O, FiO2 = 100 %) in the intervention group or NIV alone in the reference group prior to intubation. The primary outcome was the lowest oxygen saturation (SpO2) during the intubation procedure. Secondary outcomes were intubation-related complications and ICU mortality.

RESULTS

Between July 2015 and February 2016, we randomly assigned 25 and 24 patients to the intervention and reference groups, respectively. In both groups the main reasons for respiratory failure were pneumonia and ARDS. During the intubation procedure, the lowest SpO2 values were significantly higher in the intervention group than in the reference group [100 (95-100) % vs. 96 (92-99) %, p = 0.029]. After exclusion of two patients from analysis for protocol violation, no (0 %) patients in the intervention group and five (21 %) patients in the reference group had SpO2 below 80 % (p = 0.050). We recorded no significant difference between the groups in intubation-related complications or ICU mortality.

CONCLUSIONS

A novel strategy for preoxygenation in hypoxaemic patients, adding HFNC for apnoeic oxygenation to NIV prior to orotracheal intubation, may be more effective in reducing the severity of oxygen desaturation than the reference method using NIV alone.

New method of preoxygenation for orotracheal intubation in patients with hypoxaemic acute respiratory failure in the intensive care unit, non-invasive ventilation combined with apnoeic oxygenation by high flow nasal oxygen: the randomised OPTINIV study protocol

INTRODUCTION

Tracheal intubation in the intensive care unit (ICU) is associated with severe life-threatening complications including severe hypoxaemia. Preoxygenation before intubation has been recommended in order to decrease such complications. Non-invasive ventilation (NIV)-assisted preoxygenation allows increased oxygen saturation during the intubation procedure, by applying a positive end-expiratory pressure (PEEP) to prevent alveolar derecruitment. However, the NIV mask has to be taken off after preoxygenation to allow the passage of the tube through the mouth. The patient with hypoxaemia does not receive oxygen during this period, at risk of major hypoxaemia. High-flow nasal cannula oxygen therapy (HFNC) has a potential for apnoeic oxygenation during the apnoea period following the preoxygenation with NIV. Whether application of HFNC combined with NIV is more effective at reducing oxygen desaturation during the intubation procedure compared with NIV alone for preoxygenation in patients with hypoxaemia in the ICU with acute respiratory failure remains to be established.

METHODS AND ANALYSIS

The HFNC combined to NIV for decreasing oxygen desaturation during the intubation procedure in patients with hypoxaemia in the ICU (OPTINIV) trial is an investigator-initiated monocentre randomised controlled two-arm trial with assessor-blinded outcome assessment. The OPTINIV trial randomises 50 patients with hypoxaemia requiring orotracheal intubation for acute respiratory failure to receive NIV (pressure support=10, PEEP=5, fractional inspired oxygen (FiO2)=100%) combined with HFNC (flow=60 L/min, FiO2=100%, interventional group) or NIV alone (reference group) for preoxygenation. The primary outcome is lowest oxygen saturation during the intubation procedure. Secondary outcomes are intubation-related complications, quality of preoxygenation and ICU mortality.

ETHICS AND DISSEMINATION

The study project has been approved by the appropriate ethics committee (CPP Sud-Méditerranée). Informed consent is required. If combined application of HFNC and NIV for preoxygenation of patients with hypoxaemia in the ICU proves superior to NIV preoxygenation, its use will become standard practice, thereby decreasing hypoxaemia during the intubation procedure and potential complications related to intubation.

TRIAL REGISTRATION NUMBER

NCT02530957.