Apnoeic oxygenation in morbid obesity: a randomised controlled trial comparing facemask and high-flow nasal oxygen delivery

Effectiveness of preoxygenation strategies: a systematic review and network meta-analysis

BACKGROUND

Preoxygenation is universally recommended before induction of general anaesthesia to prolong safe apnoea time. The optimal technique for preoxygenation is unclear. We conducted a systematic review to determine the preoxygenation technique associated with the greatest effectiveness in adult patients having general anaesthesia.

METHODS

We searched six databases for randomised controlled trials of patients aged ≥16 yr, receiving general anaesthesia in any setting and comparing different preoxygenation techniques and methods. Our primary effectiveness outcome was safe apnoea time, and secondary outcomes included incidence of arterial oxygen desaturation; lowest SpO2 during airway management; time to end-tidal oxygen concentration of 90%; and [Formula: see text] and [Formula: see text] at the end of preoxygenation. We assessed the quality of evidence according to Grading of Recommendations, Assessment, Development and Evaluation (GRADE) recommendations.

RESULTS

We included 52 studies of 3914 patients. High-flow nasal oxygen with patients in a head-up position was most likely to be associated with a prolonged safe apnoea time when compared with other strategies, with a mean difference (95% credible interval) of 291 (138-456) s and 203 (79-343) s compared with preoxygenation with a facemask in the supine and head-up positions, respectively. Subgroup analysis of studies without apnoeic oxygenation also showed high-flow nasal oxygen in the head-up position as the highest ranked technique, with a statistically significantly delayed mean difference (95% credible interval) safe apnoea time compared with facemask in supine and head-up positions of 222 (63-378) s and 139 (15-262) s, respectively. High-flow nasal oxygen was also the highest ranked technique for increased [Formula: see text] at the end of preoxygenation. However, the incidence of arterial desaturation was less likely to occur when a facemask with pressure support was used compared with other techniques, and [Formula: see text] was most likely to be lowest when preoxygenation took place with patients deep breathing in a supine position.

CONCLUSIONS

Preoxygenation of adults before induction of general anaesthesia was most effective in terms of safe apnoea time when performed with high-flow nasal oxygen with patients in the head-up position in comparison with facemask alone. Also, high-flow nasal oxygen in the head-up position is likely to be the most effective technique to prolong safe apnoea time among those evaluated. Clinicians should consider this technique and patient position in routine practice.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO CRD42022326046.

High-flow nasal oxygenation versus face mask oxygenation for preoxygenation in patients undergoing double-lumen endobronchial intubation: protocol of a randomised controlled trial

INTRODUCTION

With the growing emphasis on swift recovery, minimally invasive thoracic surgery has advanced significantly. Video-assisted thoracoscopic surgery (VATS) has seen rapid development, and the double-lumen tube (DLT) remains the most dependable method for tracheal intubation in VATS. However, hypoxaemia during DLT intubation poses a threat to the perioperative safety of thoracic surgery patients. Recently, transnasal high-flow nasal oxygen (HFNO) has shown promise in anaesthesia, particularly in handling short-duration hypoxic airway emergencies. Yet, its application in the perioperative period for patients undergoing pulmonary surgery with compromised cardiopulmonary function lacks evidence, and there are limited reliable clinical data.

METHODS AND ANALYSIS

A prospective, randomised, controlled, single-blind design will be employed in this study. 112 patients aged 18-60 years undergoing elective VATS-assisted pulmonary surgery will be enrolled and randomly divided into two groups: the nasal high-flow oxygen group (H group) and the traditional mask transnasal oxygen group (M group) in a 1:1 ratio. HFNO will be used during DLT intubation for the prevention of asphyxia in group H, while conventional intubation procedures will be followed by group M. Comparison will be made between the two groups in terms of minimum oxygen saturation during intubation, hypoxaemia incidence during intubation, perioperative complications and postoperative hospital days.

ETHICS AND DISSEMINATION

Approval for this study has been granted by the local ethics committee at Shenzhen Second People's Hospital. The trial results will be disseminated through peer-reviewed journals and scientific conferences.

TRIAL REGISTRATION NUMBER

NCT05666908.

Narrative Review and Consensus Recommendations for the Use of Transnasal Humidified Rapid-Insufflation Ventilatory Exchange in Modified Electroconvulsive Therapy

Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) is a safe, effective, and novel technique that is currently being used in electroconvulsive therapy (ECT). This study aimed to summarize the clinical practices of THRIVE use in ECT to aid physicians and institutions in implementing the best practice guidelines for ECT. Thus, we reviewed the current literature and presented our consensus on the application of THRIVE in ECT in daily clinical practice. This consensus provides information regarding THRIVE use in ECT, including its safety, effectiveness, procedures, precautions, special case management, and application in special populations. Moreover, it guides the standardized use of THRIVE in ECT.

Transnasal humidified rapid-insufflation ventilator exchange compared with laryngeal mask airway for endoscopic thoracic sympathectomy: a randomized controlled trial

Background

Transnasal humidified rapid-insufflation ventilator exchange (THRIVE) has the characteristics of operating easily and maintaining oxygenation and eliminating CO2, which makes it possible to be used in endoscopic thoracic sympathectomy (ETS). The application of THRIVE in ETS remains undefined. The purpose of this randomized controlled study is to assess the efficacy between THRIVE and laryngeal mask airway (LMA) for ETS.

Methods

In total, 34 patients from May 2022 to May 2023 in Huazhong University of Science and Technology Union Shenzhen Hospital undergoing ETS were randomly divided into a THRIVE group (n = 17) and an LMA group (n = 17). A serial arterial blood gas analysis was conducted during the perioperative period. The primary outcome was the arterial partial pressure of carbon dioxide (PaCO2) during the perioperative period. The secondary outcome was arterial partial pressure of oxygen (PaO2) during the perioperative period.

Results

The mean (SD) highest PaCO2 in the THRIVE group and LMA group were 99.0 (9.0) mmHg and 51.7 (5.2) mmHg, respectively (p < 0.001). The median (inter-quartile range) time to PaCO2 ≥ 60 mmHg in the THRIVE group was 26.0 min (23.2-28.8). The mean (SD) PaO2 was 268.8 (89.0) mmHg in the THRIVE group and 209.8 (55.8) mmHg in the LMA group during surgery (p = 0.027).

Conclusion

CO2 accumulation in the THRIVE group was higher than that of the LMA group during ETS, but THRIVE exhibited greater oxygenation capability compared to LMA. We preliminarily testified that THRIVE would be a feasible non-intubated ventilation technique during ETS under monitoring PaCO2.

Perioperative management of Obstructive Sleep Apnoea: Present themes and future directions

PURPOSE OF REVIEW

Obstructive sleep apnoea (OSA) is an increasingly common pathology that all those involved in perioperative care will come across. Patients with the condition present a challenge at many stages along the perioperative journey, not least because many patients living with OSA are unaware of their diagnosis.Key interventions can be made pre, intra-, and postoperatively to improve outcomes. Knowledge of screening tools, diagnostic tests, and the raft of treatment options are important for anyone caring for these patients.

RECENT FINDINGS

Recent literature has highlighted the increasing complexity of surgical patients and significant underdiagnosis of OSA in this patient population. Work has demonstrated how and why patients with OSA are at a higher perioperative risk and that effective positive airways pressure (PAP) therapy can reduce these risks, alongside evidencing how best to optimise adherence to therapy, a key issue in OSA.

SUMMARY

OSA, and particularly undiagnosed OSA, presents a huge problem in the perioperative period. Perioperative PAP reduces the risk of postoperative complications but adherence remains an issue. Bespoke perioperative pathways should be developed to identify and optimise high risk patients, although at present evidence on how best to achieve this is lacking.

High-Flow Oxygen Therapy in the Perioperative Setting and Procedural Sedation: A Review of Current Evidence

High-flow oxygen therapy (HFOT) is a respiratory support system, through which high flows of humidified and heated gas are delivered to hypoxemic patients. Several mechanisms explain how HFOT improves arterial blood gases and enhances patients' comfort. Some mechanisms are well understood, but others are still unclear and under investigation. HFOT is an interesting oxygen-delivery modality in perioperative medicine that has many clinical applications in the intensive care unit (ICU) and the operating room (OR). The purpose of this article was to review the literature for a comprehensive understanding of HFOT in the perioperative period, as well as its uses in procedural sedation. This review will focus on the HFOT definition, its physiological benefits, and their mechanisms, its clinical uses in anesthesia, and when it is contraindicated.

Improvements in cuirass ventilation for airway surgery: origins in Copenhagen on the 70th anniversary of the first intensive care unit

The first modern intensive care unit was established in Copenhagen 70 yr ago. This cornerstone of anaesthesia was largely based on experience gained using positive pressure ventilation to save hundreds of patients during the polio epidemic in 1952. Ventilation approaches, monitoring techniques, and pharmacological innovations have developed to such an extent that cuirass ventilation, which proved inadequate during the polio epidemic, might now have novel applications for both anaesthesia and treatment of the critically ill.

Effectiveness of high-flow nasal cannula oxygen in apneic oxygenation during intubation in high-risk surgical patients: a systematic review protocol

OBJECTIVE

This review will investigate the effectiveness of high-flow nasal oxygen in apneic oxygenation through safe apnea time and other ventilation parameters in patients at high risk of oxygen desaturation during induction and tracheal intubation for anesthesia management.

INTRODUCTION

High-risk surgical patient groups include obese patients, those with suspected or known obstructive sleep apnea, and critically ill patients, who are at risk of rapid oxygen desaturation during intubation. Conventional oxygen administration in induction and intubation of patients undergoing general anesthesia include nasal cannulas, simple face masks, Venturi, buccal oxygenation, bag-valve mask ventilation, and non-invasive ventilation. High-flow nasal oxygen has emerged as a novel technique, and is advantageous because it increases positive end-expiratory pressure and oxygen delivered.

INCLUSION CRITERIA

Eligible studies will include high-risk surgical patients aged 18 or above requiring endotracheal intubation in both emergency and elective anesthetic settings. High-risk patients are defined as those with suspected or known obstructive sleep apnea, obesity (BMI > 35), or critically ill patients (scored the American Society of Anesthesiologists classification as 3 or above).

METHODS

The review will follow the JBI methodology for systematic reviews of effectiveness. Databases to be searched include MEDLINE, Embase, and Scopus. Reference lists of selected studies will then be hand-searched for additional eligible studies. The primary outcome will be safe apnea time, with secondary outcomes including oxygen and carbon dioxide parameters, and adverse events (eg, gastric distension). Studies will, where possible, be pooled in statistical meta-analyses with data heterogeneity assessed using the standard χ2 and I2 tests.

REVIEW REGISTRATION

PROSPERO CRD42022312145.

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.

Effect of high-flow nasal cannula versus non-invasive ventilation after extubation on successful extubation in obese patients: a retrospective analysis of the MIMIC-IV database

BACKGROUND

The pathophysiological characteristics of the respiratory system of obese patients differ from those of non-obese patients. Few studies have evaluated the effects of high-flow nasal cannula (HFNC) and non-invasive ventilation (NIV) on the prognosis of obese patients. We here compared the effects of these two techniques on the prevention of reintubation after extubation for obese patients.

METHODS

Data were extracted from the Medical Information Mart for Intensive Care database. Patients who underwent HFNC or NIV treatment after extubation were assigned to the HFNC or NIV group, respectively. The reintubation risk within 96 hours postextubation was compared between the two groups using a doubly robust estimation method. Propensity score matching was performed for both groups.

RESULTS

This study included 757 patients (HFNC group: n=282; NIV group: n=475). There was no significant difference in the risk of reintubation within 96 hours after extubation for the HFNC group compared with the NIV group (OR 1.50, p=0.127). Among patients with body mass index ≥40 kg/m2, the HFNC group had a significantly lower risk of reintubation within 96 hours after extubation (OR 0.06, p=0.016). No significant differences were found in reintubation rates within 48 hours (15.6% vs 11.0%, p=0.314) and 72 hours (16.9% vs 13.0%, p=0.424), as well as in hospital mortality (3.2% vs 5.2%, p=0.571) and intensive care unit (ICU) mortality (1.3% vs 5.2%, p=0.108) between the two groups. However, the HFNC group had significantly longer hospital stays (14 days vs 9 days, p=0.005) and ICU (7 days vs 5 days, p=0.001) stays.

CONCLUSIONS

This study suggests that HFNC therapy is not inferior to NIV in preventing reintubation in obese patients and appears to be advantageous in severely obese patients. However, HFNC is associated with significantly longer hospital stays and ICU stays.

Comparing nasopharyngeal apnoeic oxygenation at 18 l/min to preoxygenation alone in obese patients - A randomised controlled study

STUDY OBJECTIVE

Investigate a low-cost, nasopharyngeal apnoeic oxygenation technique, establish its efficacy, and compare it to preoxygenation only in an obese population. The study's hypothesis was that nasopharyngeal apnoeic oxygenation at 18 l.min^-1 would significantly prolong safe apnoea time compared to preoxygenation alone.

DESIGN

Randomised controlled study.

SETTING

Theatre complex of a resource constrained hospital.

PATIENTS

30 adult, obese (BMI ≥ 35 kg.m^-2) patients presenting for elective surgery. Patients with limiting cardio-respiratory disease, suspected difficult airway, risk of aspiration, and that were pregnant, were excluded. Patients were allocated by block randomisation in a 1:2 ratio to a preoxygenation-only (No-AO) and an intervention group (NPA-O₂).

INTERVENTIONS

All patients were preoxygenated to an Et-O2 > 80%, followed by a standardised induction. The intervention group received oxygen at 18 l.min^-1 via the nasopharyngeal catheter intervention. The desaturation process was documented until an SpO₂ of 92% or 600 s was reached.

MEASUREMENTS

Baseline demographic and clinical characteristics were collected. The primary outcome was safe apnoea time, defined as the time taken to desaturate to an SpO₂ of 92%. Secondary outcomes were rate of carbon dioxide accumulation and factors affecting the risk of desaturation.

MAIN RESULTS

The study was conducted in a morbidly obese population (NoAO = 41,1 kg.m^-2; NPA-O₂ = 42,5 kg.m^-2). The risk of desaturation was signifantly lower in the intervention group (Hazzard Ratio = 0,072, 95% CI[0,019-0,283]) (Log-Rank test, p < 0.001). The median safe apnoea time was significantly longer in the intervention group (NoAO = 262 s [IQR 190-316]; NPA-O₂ = 600 s [IQR 600-600]) (Mann-Whitney-U test, p < 0.001). The mean rate of CO₂ accumalation was significantly slower in the intervention group (NoAO = 0,47 ± 0,14 kPa.min^-1; NPA-O₂ = 0,3 ± 0,09 kPa.min^-1) (t-test, p = 0.003). There were no statistically significant risk factors associated with an increased risk of desaturation found.

CONCLUSIONS

Nasopharyngeal apnoeic oxygenation at 18 l/min prolongs safe apnoea time, compared to preoxygenation alone, and reduces the risk of desaturation in morbidly obese patients.

CLINICAL TRIAL REGISTRATION

PACTR202202665252087; WC/202004/007.

High-Flow Nasal Cannula for Apneic Oxygenation in Obese Patients for Elective Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Obese patients desaturate rapidly during the apneic period after induction of anesthesia for elective surgery. Administration of oxygen using high-flow nasal cannulae (HFNCs) may prevent desaturation in nonobese patients compared to facemask (FM) preoxygenation. The aim of this meta-analysis was to compare the effectiveness of HFNC to FM preoxygenation techniques in reducing preintubation desaturation in obese patients undergoing elective surgery.

METHODS

This study protocol was registered on PROSPERO (CRD42022309391). Adult studies that compared HFNC and FM preoxygenation in obese patients requiring general anesthesia for elective surgery were included. The primary outcome was desaturation resulting in oxygen saturation of <92% from induction of anesthesia until intubation. Secondary outcomes included the lowest arterial oxygen content before intubation expressed in mm Hg, safe apnea time expressed in seconds, the lowest oxygen saturation before intubation expressed as a percentage, patient-reported discomfort, the need for rescue ventilation, and the incidence of aspiration of gastric contents during intubation. Risk of bias was assessed using the Cochrane Collaboration tool. Certainty was assessed following the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

Six studies including 351 participants were eligible for analysis. There was no difference in odds of oxygen desaturation <92% between HFNC and FM (odds ratio [OR], 0.49; 95% confidence interval [CI], 0.15-1.63; P = .24). The HFNC group had a significantly longer safe apnea time (mean difference [MD], -124.20 with 95% CI, -200.47 to -47.93; P = .001). There was no difference between HFNC and FM in the lowest arterial oxygen content (MD, -23.90; 95% CI, -88.64 to 40.85; P = .47) and the lowest peripheral oxygenation saturation (MD, -0.47 with 95% CI, -5.07 to 4.12; P = .84). HFNC had a lower odd of discomfort than FM (OR, 0.13; 95% CI, 0.03-0.52; P = .004). There was no difference in the odds of aspiration of gastric contents between HFNC and FM (OR, 0.33; 95% CI, 0.01-8.21; P = .50). The risk of bias for our primary and secondary outcomes was low. The GRADE assessment for our primary outcome indicated a low level of certainty. For secondary outcomes, the GRADE assessment indicated a very low certainty for all outcomes except for patient discomfort, which was indicated as a moderate level of certainty.

CONCLUSIONS

There may be no difference between HFNC and FM preoxygenation in preventing oxygen desaturation <92% or the lowest oxygen saturation before intubation. Preparation remains important to prevent and manage desaturation during induction of obese patients.

Efficacy of High-Flow Nasal Cannula versus Conventional Oxygen Therapy in Obese Patients during the Perioperative Period: A Systematic Review and Meta-Analysis

Background. Obesity is a risk factor for severe airway obstruction and hypoxemia. High-flow nasal cannula (HFNC) is considered as a novel method for oxygen therapy, but the efficacy of HFNC for obese patients is controversial. This meta-analysis aimed to assess the efficacy of HFNC compared with conventional oxygen therapy (COT) in obese patients during the perioperative period. Methods. We searched the PubMed, Embase, Web of Science, the Cochrane Library, and Google scholar databases for randomized controlled trials (RCTs) that compared the efficacy of HFNC with COT in obese patients during the perioperative period. The primary outcome was the incidence of hypoxemia, while the secondary outcomes included the lowest SpO2, the need for additional respiratory support, and the hospital length of stay (LOS). Results. Twelve trials with 798 obese patients during the perioperative period were included. Compared with COT, HFNC reduced the incidence of hypoxemia (RR, 0.60; 95% CI, 0.43 to 0.83; $P=0.002$ ; I2 = 24%; 8 RCTs; n = 458), increased the lowest SpO2 (MD, 2.88; 95% CI, 1.53 to 4.22; $P<0.0001$ ; I2 = 32%; 5 RCTs; n = 264), decreased the need for additional respiratory support (RR, 0.43; 95% CI, 0.21 to 0.88; $P=0.02$ ; I2 = 0%; 3 RCTs; n = 305), and shortened the hospital LOS (MD, −0.31; 95% CI, −0.57 to −0.04; $P=0.02$ ; I2 = 0%; 3 RCTs; n = 214). Conclusions. This meta-analysis showed that compared with COT, the use of HFNC was able to reduce the incidence of hypoxemia, increase the lowest SpO2, decrease the need for additional respiratory support, and shorten the hospital LOS in obese patients during the perioperative period. Well-organized trials with large sample size should be conducted to support our findings.

Peri-intubation oxygenation for Caesarean delivery: is there an optimal technique?

Peri-intubation oxygen administration to the pregnant patient during induction of general anaesthesia is critical to avoiding hypoxaemia and harm to the mother and fetus. Recent modelling comparing low-flow with high-flow nasal oxygen in simulated term pregnant women of varying body habitus, taken together with previous work, suggests that face mask preoxygenation with the use of low-flow or high-flow nasal oxygen during the period of apnoea prolongs the safe apnoea period, with the benefit varying by body habitus. Low-flow compared with high-flow nasal oxygen may be easier to combine with face mask preoxygenation and is readily available in all operating theatres, although future improvements in high-flow nasal oxygen delivery systems may improve ease of use for this indication.

A Comparison of Oxygenation Efficacy between High-Flow Nasal Cannulas and Standard Facemasks during Elective Tracheal Intubation for Patients with Obesity: A Randomized Controlled Trial

Obese patients are predisposed to rapid oxygen desaturation during tracheal intubation. We aimed to compare the risk of desaturation between high-flow nasal oxygenation (HFNO) and classical facemask oxygenation (FMO) during rapid sequence intubation for elective surgery in obese patients. Adults with a body mass index ≥30 kg·m−2 undergoing laparoscopic sleeve gastrectomy at a medical center were randomized into the HFNO group (n = 40) and FMO group (n = 40). In the HFNO group, patients used a high-flow nasal cannula to receive 30 to 50 L·min−1 flow of heated and humidified 100% oxygen. In the FMO group, patients received a fitting facemask with 15 L·min−1 flow of 100% oxygen. After 5-min preoxygenation, rapid sequence intubation was performed. The primary outcome was arterial desaturation during intubation, defined as a peripheral capillary oxygen saturation (SpO2) <92%. The risk of peri-intubation desaturation was significantly lower in the HFNO group compared to the FMO group; absolute risk reduction: 0.20 (95% confidence interval: 0.05−0.35, p = 0.0122); number needed to treat: 5. The lowest SpO2 during intubation was significantly increased by HFNO (median 99%, interquartile range: 97−100) compared to FMO (96, 92−100, p = 0.0150). HFNO achieved a higher partial pressure of arterial oxygen (PaO2) compared to FMO, with medians of 476 mmHg (interquartile range: 390−541) and 397 (351−456, p = 0.0010), respectively. There was no difference in patients’ comfort level between groups. Compared with standard FMO, HFNO with apneic oxygenation reduced arterial desaturation during tracheal intubation and enhanced PaO2 among patients with obesity.