Use of high-flow nasal cannula oxygen therapy to prevent desaturation during tracheal intubation of intensive care patients with mild-to-moderate hypoxemia. Crit Care Med. 2015;43:574-583. [PMID: 25479117 DOI: 10.1097/ccm.0000000000000743]

Pre-oxygenation using high flow humidified nasal oxygen or face mask oxygen in pregnant people - a prospective randomised controlled crossover non-inferiority study (The HINOP2 study)

BACKGROUND

Airway guidelines recommend pre-oxygenation of obstetric patients to an end tidal oxygen concentration (etO2) ≥90%. High flow nasal oxygen (HFNO) achieves this in 60% of pregnant people. However face mask (FM) pre-oxygenation also may not achieve this target in all patients. In this study we determined whether HFNO pre-oxygenation is non-inferior to FM pre-oxygenation.

METHODS

This randomised controlled crossover non-inferiority trial was conducted on healthy participants of gestational age ≥37 weeks in a simulated environment. Participants underwent pre-oxygenation for three minutes with HFNO and FM oxygen in randomised order. HFNO was delivered at a maximal flow of 70 l.min-1 and FM oxygen at 10 l.min-1. The primary outcome was etO2 on first expired breath after pre-oxygenation. Non-inferiority was defined as a mean difference in first etO2 between groups of ≤5%.

RESULTS

Seventy participants were randomised with 62 analysed. Age (mean (SD)), gestation (median (IQR)), and body mass index (median (IQR)), were 34.7 (4.6) years, 39 (38.4, 39.4) weeks, 29 (26.6, 32.4) kg.m-2 respectively. First etO2 after HFNO pre-oxygenation was greater than after FM pre-oxygenation (HFNO pre-oxygenation mean (SD) 90.2 (3.9)% versus FM pre-oxygenation 88.7 (3.0)%; mean difference = 1.45%, 95% CI 0.19 to 2.72%; p = 0.025. Forty-four (71%) participants achieved ≥90% first etO2 concentration after HFNO pre-oxygenation versus 27 (44%) after FM pre-oxygenation (p = 0.002).

CONCLUSIONS

In this cohort of pregnant people at term in a simulated environment, pre-oxygenation with HFNO was not inferior to FM pre-oxygenation. FM pre-oxygenation did not achieve pre-oxygenation targets in over 50% of participants.

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.

Society of Critical Care Medicine Clinical Practice Guidelines for Rapid Sequence Intubation in the Critically Ill Adult Patient

RATIONALE

Controversies and practice variations exist related to the pharmacologic and nonpharmacologic management of the airway during rapid sequence intubation (RSI).

OBJECTIVES

To develop evidence-based recommendations on pharmacologic and nonpharmacologic topics related to RSI.

DESIGN

A guideline panel of 20 Society of Critical Care Medicine members with experience with RSI and emergency airway management met virtually at least monthly from the panel's inception in 2018 through 2020 and face-to-face at the 2020 Critical Care Congress. The guideline panel included pharmacists, physicians, a nurse practitioner, and a respiratory therapist with experience in emergency medicine, critical care medicine, anesthesiology, and prehospital medicine; consultation with a methodologist and librarian was available. A formal conflict of interest policy was followed and enforced throughout the guidelines-development process.

METHODS

Panelists created Population, Intervention, Comparison, and Outcome (PICO) questions and voted to select the most clinically relevant questions for inclusion in the guideline. Each question was assigned to a pair of panelists, who refined the PICO wording and reviewed the best available evidence using predetermined search terms. The Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework was used throughout and recommendations of "strong" or "conditional" were made for each PICO question based on quality of evidence and panel consensus. Recommendations were provided when evidence was actionable; suggestions, when evidence was equivocal; and best practice statements, when the benefits of the intervention outweighed the risks, but direct evidence to support the intervention did not exist.

RESULTS

From the original 35 proposed PICO questions, 10 were selected. The RSI guideline panel issued one recommendation (strong, low-quality evidence), seven suggestions (all conditional recommendations with moderate-, low-, or very low-quality evidence), and two best practice statements. The panel made two suggestions for a single PICO question and did not make any suggestions for one PICO question due to lack of evidence.

CONCLUSIONS

Using GRADE principles, the interdisciplinary panel found substantial agreement with respect to the evidence supporting recommendations for RSI. The panel also identified literature gaps that might be addressed by future research.

Ultrasound Assessment of Gastric Volume in Parturients After High-Flow Nasal Oxygen Therapy

BACKGROUND

High-flow nasal oxygen (HFNO) therapy is widely used in critical care obstetrics to improve oxygenation. Much of the benefit of HFNO is linked to the creation of modest levels of positive airway pressure. Pregnant women are generally considered to be at high risk of regurgitation and aspiration. It is unknown whether HFNO may cause gas insufflation into the stomach and further increase this risk. Therefore, this study aimed to systematically evaluate the possible safety effects of HFNO on gastric volume in healthy fasted parturients.

METHODS

Sixty fasted parturients scheduled for elective cesarean delivery were enrolled in an observer-blinded, prospective, interventional study. We used ultrasonography to assess changes of antral cross-sectional area (CSA) and gastric volume before and after a 20-minute treatment with HFNO at a rate of 50 L·min -1 . The primary outcome was the change in gastric volume from before to after HFNO therapy, and the secondary outcome was the distribution of antral grades.

RESULTS

In semirecumbent right lateral position, the antral CSA at baseline and after treatment with HFNO was 3.81 (3.01-4.72) cm 2 and 3.79 (3.03-4.54) cm 2 , respectively. The estimated fluid volume at baseline and after treatment with HFNO was 38.51 (33.39-54.62) mL and 39.71 (32.00-52.82) mL, respectively. All participants had either a grade 0 or grade 1 antrum, and most of them had a grade 0 antrum. There was no significant difference in gastric volume and distribution of antral grades before and after HFNO therapy. Gastric air distension was not shown in any of the parturients either at baseline or after treatment with HFNO.

CONCLUSIONS

Treatment with HFNO for 20 minutes at flow rates up to 50 L·min -1 did not increase gastric volume in term pregnant women breathing spontaneously when evaluated by gastric ultrasonography.

The Impact of High-Flow Nasal Cannula Therapy on Acute Respiratory Distress Syndrome Patients: A Systematic Review

High-flow nasal cannula (HFNC) is a novel oxygenation approach in the management of acute respiratory distress syndrome (ARDS). This systematic review was focused on evaluating current evidence concerning the efficacy of HFNC in ARDS and its comparison with standard treatment approaches. For this review, a systematic search was undertaken in PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, Web of Science, Cochrane Library, and Google Scholar to identify relevant studies. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. All those studies that investigated the impact of HFNC on ARDS patients and were published in the English language were included. The literature search from all databases provided 6157 potentially relevant articles from PubMed (n = 1105), CINAHL (n = 808), Web of Science (n = 811), Embase (n = 2503), Cochrane database (n = 930), and Google Scholar (n = 46). After the exclusion of studies that did not fulfill the criteria, 18 studies were shortlisted for the scope of this systematic review. Among the included studies, five focused on HFNC's impact on COVID-19-related ARDS, whereas 13 studies focused on HFNC's impact on ARDS patients. Most studies demonstrated the efficacy of HFNC in managing ARDS, with some studies showing comparable efficacy and higher safety compared to noninvasive ventilation (NIV). This systematic review highlights the potential benefits of HFNC in ARDS management. The findings show that HFNC is effective in reducing the respiratory distress symptoms, the incidence of invasive ventilation, and the adverse events associated with ARDS. These findings can help clinical decision-making processes and contribute to the evidence base for optimal ARDS management strategies.

Comparison of preoxygenation efficiency measured by the oxygen reserve index between high-flow nasal oxygenation and facemask ventilation: a randomised controlled trial

BACKGROUND

High-flow nasal oxygenation and the oxygen reserve index (ORI), which is a non-invasive and innovative modality that reflects the arterial oxygen content, are used in general anaesthesia. This study compares the preoxygenation efficiency (measured by the ORI) of high-flow nasal oxygenation and facemask ventilation during the induction process.

METHODS

This single-centre, two-group, randomised controlled trial included 197 patients aged ≥ 20 years who underwent orotracheal intubation for general anaesthesia for elective surgery. The patients were randomly allocated to receive preoxygenation via facemask ventilation or high-flow nasal oxygenation. The ORI was measured and compared between both groups.

RESULTS

The ORI increased during preoxygenation in all patients. At 1 min of preoxygenation, the ORI was significantly higher in the high-flow nasal oxygenation group (0.34 ± 0.33) than in the facemask ventilation group (0.21 ± 0.28; P = 0.003). The highest ORI was not significantly different between the two groups (0.68 ± 0.25 in the high-flow nasal oxygenation group vs. 0.70 ± 0.28 in the facemask ventilation group; P = 0.505).

CONCLUSIONS

High-flow nasal oxygenation results in an oxygenation status similar to that provided by facemask ventilation during the induction process of general anaesthesia; therefore, high-flow nasal oxygenation is a feasible preoxygenation method.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT04291339).

Oxygen therapy alternatives in COVID-19: From classical to nanomedicine

Around 10-15% of COVID-19 patients affected by the Delta and the Omicron variants exhibit acute respiratory insufficiency and require intensive care unit admission to receive advanced respiratory support. However, the current ventilation methods display several limitations, including lung injury, dysphagia, respiratory muscle atrophy, and hemorrhage. Furthermore, most of the ventilatory techniques currently offered require highly trained professionals and oxygen cylinders, which may attain short supply owing to the high demand and misuse. Therefore, the search for new alternatives for oxygen therapeutics has become extremely important for maintaining gas exchange in patients affected by COVID-19. This review highlights and suggest new alternatives based on micro and nanostructures capable of supplying oxygen and/or enabling hematosis during moderate or acute COVID-19 cases.

[The role of HFNC oxygen in pre-oxygenation prior to intubation and the practice of invasive procedures]

Over recent years, High Flow Nasal Cannula (HFNC) oxygen therapy has been more and more extensively applied in numerous medical settings, and it is now carried out in invasive procedures such as pre-oxygenation before orotracheal intubation, often leading to complications. More generally, pre-oxygenation is aimed at maintaining the highest possible oxygen saturation for extended periods of time. With this in mind, HFNC seems as effective as standard oxygen delivery with regard to hematosis in patients with mild or moderate hypoxemia, and it presents the advantage of reducing the adverse events associated with intubation. That said, during pre-oxygenation of patients with severe hypoxemia, non-invasive ventilation (NIV) is probably more effective than HFNC, especially in the prevention of respiratory events. However, in patients with little or no hypoxemia undergoing risky procedures such as bronchial endoscopy, HFNC allows better oxygen saturation than standard methods. To summarize, even though NIV remains useful in unstable patients, especially in decreasing desaturation episodes, HFNC could represent a reasonable alternative in case of poor tolerance, allowing continuous oxygenation of patients requiring digestive endoscopy or trans-esophageal ultrasound.

[The perioperative role of high-flow cannula oxygen (HFNO)]

High-flow nasal cannula oxygen (HFNO) is commonly used during the perioperative period. Its numerous physiological benefits, satisfactory tolerance and ease of use have led to its widespread application in intensive care and post-anesthesia care units. HFNO is also used in the operating theater in multiple indications: as oxygen supplementation (associated with pressurization) prior to orotracheal intubation; in digestive and bronchial endoscopies, especially in patients at risk of hypoxemia; and in intraoperative surgery requiring spontaneous ventilation (ENT, thoracic surgery…). During the postoperative period, HFNO can be used in a curative strategy for respiratory failure or in a prophylactic strategy to prevent reintubation. In a curative approach, HFNO seems of interest following cardiac or thoracic surgery but has not been evaluated in respiratory failure subsequent to abdominal surgery, in which case noninvasive ventilation remains the gold standard. The risk of respiratory complications depends on type of surgery and on patient comorbidities. As prophylaxis, HFNO is currently preferred to conventional oxygen therapy after cardiac or thoracic surgery, especially in patients at high risk of respiratory complications. For the clinician, it is important to acknowledge the limits of HFNO and to closely monitor patients receiving HFNO, the objective being to avoid delays in intubation that could lead to increased mortality.

High-Flow Versus VenturiMask Oxygen Therapy to Prevent Reintubation in Hypoxemic Patients after Extubation: A Multicenter Randomized Clinical Trial

Rationale: When compared with VenturiMask after extubation, high-flow nasal oxygen provides physiological advantages. Objectives: To establish whether high-flow oxygen prevents endotracheal reintubation in hypoxemic patients after extubation, compared with VenturiMask. Methods: In this multicenter randomized trial, 494 patients exhibiting Pa_O2:Fi_O2 ratio ⩽ 300 mm Hg after extubation were randomly assigned to receive high-flow or VenturiMask oxygen, with the possibility to apply rescue noninvasive ventilation before reintubation. High-flow use in the VenturiMask group was not permitted. Measurements and Main Results: The primary outcome was the rate of reintubation within 72 hours according to predefined criteria, which were validated a posteriori by an independent adjudication committee. Main secondary outcomes included reintubation rate at 28 days and the need for rescue noninvasive ventilation according to predefined criteria. After intubation criteria validation (n = 492 patients), 32 patients (13%) in the high-flow group and 27 patients (11%) in the VenturiMask group required reintubation at 72 hours (unadjusted odds ratio, 1.26 [95% confidence interval (CI), 0.70-2.26]; P = 0.49). At 28 days, the rate of reintubation was 21% in the high-flow group and 23% in the VenturiMask group (adjusted hazard ratio, 0.89 [95% CI, 0.60-1.31]; P = 0.55). The need for rescue noninvasive ventilation was significantly lower in the high-flow group than in the VenturiMask group: at 72 hours, 8% versus 17% (adjusted hazard ratio, 0.39 [95% CI, 0.22-0.71]; P = 0.002) and at 28 days, 12% versus 21% (adjusted hazard ratio, 0.52 [95% CI, 0.32-0.83]; P = 0.007). Conclusions: Reintubation rate did not significantly differ between patients treated with VenturiMask or high-flow oxygen after extubation. High-flow oxygen yielded less frequent use of rescue noninvasive ventilation. Clinical trial registered with www.clinicaltrials.gov (NCT02107183).

The performance and safety of motorized spiral enteroscopy, including in patients with surgically altered gastrointestinal anatomy: a multicenter prospective study

BACKGROUND

Data are scarce on the efficacy and safety of motorized spiral enteroscopy (MSE). No data are available on the utility of this technique in patients with surgically altered gastrointestinal (GI) anatomy. We aimed to evaluate the safety and efficacy of MSE in patients with suspected small-bowel disease, including those with surgically altered GI anatomy.

METHODS

A multicenter prospective observational, uncontrolled study evaluated MSE in consecutive patients with suspected small-bowel pathology and an indication for diagnostic and/or therapeutic intervention.

RESULTS

A total of 170 patients (102 men; median age 64 years, range 18-89) were included. The overall diagnostic yield was 64.1 %. Endotherapy was performed in 53.5 % of procedures. The median total procedure times for the antegrade and retrograde approaches were 45 minutes (interquartile range [IQR] 30-80) and 40 minutes (IQR 30-70), respectively. When total (pan)enteroscopy was intended, this was achieved at rate of 70.3 % (28.1 % by antegrade approach and 42.2 % by a bidirectional approach). Surgically altered GI anatomy was present in 34 /170 of all procedures (20.0 %) and in 11 /45 of the successful total enteroscopy procedures (24.4 %). Propofol sedation or general anesthesia were used in 92.9 % and 7.1 % of the procedures, respectively. Minor adverse events were observed in 15.9 % of patients, but there were no major adverse events.

CONCLUSION

MSE seems to be an effective and safe endoscopic procedure. Total (pan)enteroscopy can be achieved, in one or two sessions, even in the presence of surgically altered GI anatomy. The total procedure time is relatively short. For both antegrade and retrograde MSE procedures, propofol sedation seems sufficient and safe.

Recruitment s during mechanical ventilation with sequential high-flow nasal oxygen after extubation to prevent postoperative pulmonary complications in patients undergone thoracic surgery: a protocol, prospective randomised controlled trial

INTRODUCTION

The incidence of postoperative pulmonary complications (PPCs) following thoracic surgery is high, which increases the mortality rate, prolongs the length of hospital stay and increases medical costs. Some studies have confirmed that preoperative risk assessment, intraoperative anaesthesia methods and intraoperative mechanical ventilation strategies, including recruitment manoeuvres (RMs), can reduce the incidence of PPCs. Despite these improved strategies, the incidence of PPCs remains high. However, mechanical ventilation strategies have not been studied in the postoperative period.

METHODS AND ANALYSIS

We assume that RM during mechanical ventilation with sequential high-flow nasal oxygen therapy (HFNO) after extubation can maintain the opening of the postoperative alveoli and ultimately reduce the incidence of PPCs after thoracic surgery. We will include thoracic surgery patients and divide them into the RM with sequential HFNO group and the control group. They will be given RMs and sequential HFNO or be given conventional treatment. The sample size is 654 adult patients (327 per group) undergone thoracic surgery and presenting to the intensive care unit.

ETHICS AND DISSEMINATION

This study was approved by the Biomedical Research Ethics Committee of West China Hospital of Sichuan University (REC2019-730). It is expected that this study will lead to a randomised controlled trial. We assume that the findings will provide more evidence about PPCs and improve the management of patients undergone thoracic surgery.

TRIAL REGISTRATION NUMBER

ChiCTR2100046356.

Recent advances in the use of high flow nasal oxygen therapies

High flow nasal oxygen is a relatively new option for treating patients with respiratory failure, which decreases work of breathing, improves tidal volume, and modestly increases positive end expiratory pressure. Despite well-described physiologic benefits, the clinical impact of high flow nasal oxygen is still under investigation. In this article, we review the most recent findings on the clinical efficacy of high flow nasal oxygen in Type I, II, III, and IV respiratory failure within adult and pediatric patients. Additionally, we discuss studies across clinical settings, including emergency departments, intensive care units, outpatient, and procedural settings.

How to improve intubation in the intensive care unit. Update on knowledge and devices

Tracheal intubation in the critically ill is associated with serious complications, mainly cardiovascular collapse and severe hypoxemia. In this narrative review, we present an update of interventions aiming to decrease these complications. MACOCHA is a simple score that helps to identify patients at risk of difficult intubation in the intensive care unit (ICU). Preoxygenation combining the use of inspiratory support and positive end-expiratory pressure should remain the standard method for preoxygenation of hypoxemic patients. Apneic oxygenation using high-flow nasal oxygen may be supplemented, to prevent further hypoxemia during tracheal intubation. Face mask ventilation after rapid sequence induction may also be used to prevent hypoxemia, in selected patients without high-risk of aspiration. Hemodynamic optimization and management are essential before, during and after the intubation procedure. All these elements can be integrated in a bundle. An airway management algorithm should be adopted in each ICU and adapted to the needs, situation and expertise of each operator. Videolaryngoscopes should be used by experienced operators.

Changes in lung volume estimated by electrical impedance tomography during apnea and high-flow nasal oxygenation: A single-center randomized controlled trial

Background

Previous studies concerning humidified, heated high-flow nasal oxygen delivered in spontaneously breathing patients postulated an increase in functional residual capacity as one of its physiological effects. It is unclear wheter this is also true for patients under general anesthesia.

Methodology

The sincle-center noninferiority trial was registered at ClinicalTrials.gov (NCT NCT03478774). This secondary outcome analysis shows estimated differences in lung volume changes using electrical impedance tomography between different flow rates of 100% oxygen in apneic, anesthetized and paralyzed adults prior to intubation. One hundred and twenty five patients were randomized to five groups with different flow rates of 100% oxygen: i) minimal-flow: 0.25 l.min-1 via endotracheal tube; ii) low-flow: 2 l.min-1 + continuous jaw thrust; iii) medium-flow: 10 l.min-1 + continuous jaw thrust; iv) high-flow: 70l.min-1 + continuous jaw thrust; and v) control: 70 l.min-1 + continuous video-laryngoscopy. After standardized anesthesia induction with non-depolarizing neuromuscular blockade, the 15-minute apnea period and oxygen delivery was started according to the randomized flow rate. Continuous electrical impedance tomography measurements were performed during the 15-minute apnea period. Total change in lung impedance (an estimate of changes in lung volume) over the 15-minute apnea period and times to 25%, 50% and 75% of total impedance change were calculated.

Results

One hundred and twenty five patients completed the original study. Six patients did not complete the 15-minute apnea period. Due to maloperation, malfunction and artefacts additional 54 measurements had to be excluded, resulting in 65 patients included into this secondary outcome analysis. We found no differences between groups with respect to decrease in lung impedance or curve progression over the observation period.

Conclusions

Different flow rates of humidified 100% oxygen during apnea result in comparable decreases in lung volumes. The demonstrated increase in functional residual capacity during spontaneous breathing with high-flow nasal oxygenation could not be replicated during apnea under general anesthesia with neuromuscular blockade.

Updated guideline on equipment to manage difficult airways: Australian and New Zealand College of Anaesthetists

The Australian and New Zealand College of Anaesthetists (ANZCA) recently reviewed and updated the guideline on equipment to manage a difficult airway. An ANZCA-established document development group, which included representatives from the Australasian College for Emergency Medicine and the College of Intensive Care Medicine of Australia and New Zealand, performed the review, which is based on expert consensus, an extensive literature review, and bi-nationwide consultation. The guideline (PG56(A) 2021, https://www.anzca.edu.au/getattachment/02fe1a4c-14f0-4ad1-8337-c281d26bfa17/PS56-Guideline-on-equipment-to-manage-difficult-airways) is accompanied by a detailed background paper (PG56(A)BP 2021, https://www.anzca.edu.au/getattachment/9ef4cd97-2f02-47fe-a63a-9f74fa7c68ac/PG56(A)BP-Guideline-on-equipment-to-manage-difficult-airways-Background-Paper), from which the current recommendations are reproduced on behalf of, and with the permission of, ANZCA. The updated 2021 guideline replaces the 2012 version and aims to provide an updated, objective, informed, transparent, and evidence-based review of equipment to manage difficult airways.

Facilitators and Barriers to Implementing Two Quality Improvement Interventions Across 10 Pediatric Intensive Care Units: Video Laryngoscopy-Assisted Coaching and Apneic Oxygenation

To better understand facilitators and barriers to implementation of quality improvement (QI) efforts, this study examined 2 evidence-based interventions, video laryngoscopy (VL)-assisted coaching, and apneic oxygenation (AO). One focus group with frontline clinicians was held at each of the 10 participating pediatric intensive care units. Qualitative analysis identified common and unique themes. Intervention fidelity was monitored with a priori defined success as >50% VL-assisted coaching or >80% AO use for 3 consecutive months. Eighty percent of intensive care units with VL-assisted coaching and 20% with AO met this criteria during the study period. Common facilitator themes were adequate device accessibility, having a QI culture, and strong leadership. Common barrier themes included poor device accessibility and perception of delay in care. A consistently identified theme in the successful sites was strong QI leadership, while unsuccessful sites consistently identified insufficient education. These facilitators and barriers should be proactively addressed during dissemination of these interventions.

A comparison of high-flow nasal cannula and standard facemask as pre-oxygenation technique for general anesthesia: A PRISMA-compliant systemic review and meta-analysis

BACKGROUND

Current practice guidelines recommend the use of nasal cannula as an alternative pre-oxygenation method for tracheal intubation. However, the efficacy of high-flow nasal oxygenation versus standard facemask oxygenation has not been fully evaluated.

METHODS

We searched PubMed, Cochrane Library, and ClinicalTrials.gov for English-language studies published from January 1, 2000 to November 30, 2021. We included randomized controlled trials which compared high-flow nasal oxygenation and facemask oxygenation as the pre-oxygenation maneuver. Primary outcome was arterial partial pressure of oxygen (PaO2) after pre-oxygenation. Secondary outcomes were safe apnea time, arterial desaturation during intubation, lowest peripheral capillary oxygen saturation during intubation, and patient comfort score. Random-effects models and Mantel-Haenszel method were used for data synthesis.

RESULTS

A total of 16 randomized controlled trials and 1148 patients were included. High-flow nasal oxygenation achieved a higher PaO2 compared with facemask, mean difference: 64.86 mm Hg (95% confidence interval [CI]: 32.33-97.40, P < .0001). Safe apnea time was longer in high-flow nasal oxygenation, mean difference: 131.03 seconds (95% CI: 59.39-202.66, P < .0001). There was no difference in the risk of peri-intubation desaturation or lowest peripheral capillary oxygen saturation between groups. Patient comfort score was higher in high-flow nasal oxygenation, mean difference: 1.00 (95% CI: 0.46-1.54, P = .0003).

CONCLUSION

High-flow nasal oxygenation better enhanced PaO2 and extended safe apnea time and is not inferior to facemask oxygenation in preventing desaturation during tracheal intubation. High-flow nasal oxygenation may be considered as an alternative method, especially for patients with a potential difficult airway.

High-flow nasal cannula for respiratory failure in adult patients

The high-flow nasal cannula (HFNC) has been recently used in several clinical settings for oxygenation in adults. In particular, the advantages of HFNC compared with low-flow oxygen systems or non-invasive ventilation include enhanced comfort, increased humidification of secretions to facilitate expectoration, washout of nasopharyngeal dead space to improve the efficiency of ventilation, provision of a small positive end-inspiratory pressure effect, and fixed and rapid delivery of an accurate fraction of inspired oxygen (FiO₂) by minimizing the entrainment of room air. HFNC has been successfully used in critically ill patients with several conditions, such as hypoxemic respiratory failure, hypercapneic respiratory failure (exacerbation of chronic obstructive lung disease), post-extubation respiratory failure, pre-intubation oxygenation, and others. However, the indications are not absolute, and much of the proven benefit remains subjective and physiologic. This review discusses the practical application and clinical uses of HFNC in adults, including its unique respiratory physiologic effects, device settings, and clinical indications.

Treatment of acute respiratory failure: high-flow nasal cannula

Background: High-flow nasal cannulas (HFNCs) have recently been used for several conditions, such as hypoxemic respiratory failure, hypercapnic respiratory failure, post-extubation respiratory failure, and preintubation oxygenation, in critically ill patients.Current Concepts: The advantages of HFNC compared with those of low-flow oxygen systems or noninvasive ventilation include enhanced comfort, increased humidification of secretions to facilitate expectoration, washout of the nasopharyngeal dead space to improve ventilation efficiency, provisioning for low positive end-inspiratory pressure effect, and fixed and rapid delivery of accurate fraction of inspired oxygen by minimizing the entrainment of room air. However, the indications are not absolute, with much of the proven benefit being subjective and physiologic.Discussion and Conclusion: The goal of this review is to discuss the practical application and clinical uses of HFNCs in patients with acute respiratory failure, highlighting its unique respiratory and physiologic effects, device settings, and clinical indications.

Pre- and apnoeic high-flow oxygenation for rapid sequence intubation in the emergency department (the Pre-AeRATE trial): A multicentre randomised controlled trial

INTRODUCTION

Evidence regarding the efficacy of high-flow nasal cannula (HFNC) oxygenation for preoxygenation and apnoeic oxygenation is conflicting. Our objective is to evaluate whether HFNC oxygenation for preoxygenation and apnoeic oxygenation maintains higher oxygen saturation (SpO₂) during rapid sequence intubation (RSI) in ED patients compared to usual care.

METHODS

This was a multicentre, open-label, randomised controlled trial in adult ED patients requiring RSI. Patients were randomly assigned 1:1 to either intervention (HFNC oxygenation at 60L/min) group or control (non-rebreather mask for preoxygenation and nasal prongs of at least 15L/min oxygen flow for apnoeic oxygenation) group. Primary outcome was lowest SpO₂ during the first intubation attempt. Secondary outcomes included incidence of SpO₂ falling below 90% and safe apnoea time.

RESULTS

One hundred and ninety patients were included, with 97 in the intervention and 93 in the control group. Median lowest SpO₂ during the first intubation attempt was 100% in both groups. Incidence of SpO₂ falling below 90% was lower in the intervention group (15.5%) compared to the control group (22.6%) (adjusted relative risk=0.68, 95% confidence interval [CI] 0.37-1.25). Post hoc quantile regression analysis showed that the first quartile of lowest SpO₂ during the first intubation attempt was greater by 5.46% (95% CI 1.48-9.45%, P=0.007) in the intervention group.

CONCLUSION

Use of HFNC for preoxygenation and apnoeic oxygenation, when compared to usual care, did not improve lowest SpO₂ during the first intubation attempt but may prolong safe apnoea time.

High-flow versus conventional nasal cannula oxygen supplementation therapy and risk of hypoxia in gastrointestinal endoscopies: Α systematic review and meta-analysis

BACKGROUND AND AIMS

Gastrointestinal endoscopy (GIE) represents a mainstay diagnostic and therapeutic procedure in modern clinical practice. Hypoxemia and respiratory failure during endoscopy constitute major complications and concerns for endoscopists. Emerging evidence supports the utilization of high-flow nasal cannula (HFNC) over conventional nasal cannula (CNC) for oxygen supplementation and avoidance of hypoxemia. Aim of our study was to compare the risk of hypoxemia in patients undergoing GIE with HFNC versus CNC oxygen supplementation recruited by randomized controlled trials (RCTs).

METHODS

We conducted an electronic literature search in established medical databases i.e. PubMed, EMBASE and Cochrane to identify RCTs investigating the abovementioned association. The enrolled studies were evaluated for risk of bias and inserted into a random effects model for meta-analysis; sub-group analyses and publication bias were also assessed.

RESULTS

Out of 271 initially retrieved articles, five RCTs were eligible for meta-analysis with totally 2656 recruited patients (1299 HFNC and 1357 CNC). A statistically significant reduced relative risk (RR) of hypoxemia among HFNC patients was revealed (RR=0.18, CI95%: 0.05-0.61), whilst with high heterogeneity (I²:79.94%, p<0.01). Patients undergoing upper GIE with HFNC displayed a significantly lower risk of hypoxemia (96%, p<0.001, I²:15.59%), even after exclusion of endoscopic retrograde cholangiopancreatography (ERCP) cases (RR:0.03, CI95%: 0.01-0.21), albeit with higher heterogeneity (I²:41.82%). Contrariwise, colonoscopy with HFNC did not yield a statistically significant RR reduction (p=0.14).

CONCLUSION

Patients undergoing upper GIE with HFNC oxygen experience significantly less hypoxemia burden than CNC counterparts. Further research is warranted to establish this emerging association to target optimal safety during endoscopy.

Carbon Dioxide Changes during High-flow Nasal Oxygenation in Apneic Patients: A Single-center Randomized Controlled Noninferiority Trial

BACKGROUND

Anesthesia studies using high-flow, humidified, heated oxygen delivered via nasal cannulas at flow rates of more than 50 l · min-1 postulated a ventilatory effect because carbon dioxide increased at lower levels as reported earlier. This study investigated the increase of arterial partial pressure of carbon dioxide between different flow rates of 100% oxygen in elective anesthetized and paralyzed surgical adults before intubation.

METHODS

After preoxygenation and standardized anesthesia induction with nondepolarizing neuromuscular blockade, all patients received 100% oxygen (via high-flow nasal oxygenation system or circuit of the anesthesia machine), and continuous jaw thrust/laryngoscopy was applied throughout the 15-min period. In this single-center noninferiority trial, 25 patients each, were randomized to five groups: (1) minimal flow: 0.25 l · min-1, endotracheal tube; (2) low flow: 2 l · min-1, continuous jaw thrust; (3) medium flow: 10 l · min-1, continuous jaw thrust; (4) high flow: 70 l · min-1, continuous jaw thrust; and (5) control: 70 l · min-1, continuous laryngoscopy. Immediately after anesthesia induction, the 15-min apnea period started with oxygen delivered according to the randomized flow rate. Serial arterial blood gas analyses were drawn every 2 min. The study was terminated if either oxygen saturation measured by pulse oximetry was less than 92%, transcutaneous carbon dioxide was greater than 100 mmHg, pH was less than 7.1, potassium level was greater than 6 mmol · l-1, or apnea time was 15 min. The primary outcome was the linear rate of mean increase of arterial carbon dioxide during the 15-min apnea period computed from linear regressions.

RESULTS

In total, 125 patients completed the study. Noninferiority with a predefined noninferiority margin of 0.3 mmHg · min-1 could be declared for all treatments with the following mean and 95% CI for the mean differences in the linear rate of arterial partial pressure of carbon dioxide with associated P values regarding noninferiority: high flow versus control, -0.0 mmHg · min-1 (-0.3, 0.3 mmHg · min-1, P = 0.030); medium flow versus control, -0.1 mmHg · min-1 (-0.4, 0.2 mmHg · min-1, P = 0.002); low flow versus control, -0.1 mmHg · min-1 (-0.4, 0.2 mmHg · min-1, P = 0.003); and minimal flow versus control, -0.1 mmHg · min-1 (-0.4, 0.2 mmHg · min-1, P = 0.004).

CONCLUSIONS

Widely differing flow rates of humidified 100% oxygen during apnea resulted in comparable increases of arterial partial pressure of carbon dioxide, which does not support an additional ventilatory effect of high-flow nasal oxygenation.

EDITOR’S PERSPECTIVE

Design and engineering application of medical oxygen supply system in novel coronavirus pneumonia treatment hospital

Respiratory supporting, as an important medical treatment for new coronavirus pneumonia patients, must be effectively guaranteed by medical oxygen supply. However, the medical oxygen system designed and configured by the existing hospitals according to the current specifications cannot meet the oxygen needs for patients with new coronavirus pneumonia. This paper aimed to study the design of medical oxygen system in new coronavirus pneumonia emergency hospital. By investigating the oxygen treatment plan for the novel coronavirus pneumonia patients in the health emergency hospital, the oxygen treatment characteristics of different patients were studied. The oxygen characteristics of different respiratory support terminals were explored to study the oxygen demands of new coronavirus pneumonia emergency hospitals. Through calculating flow rates of medical gas system air source referring to ‘technical code for medical gases engineering’, the proportion coefficient of severe patients converted into respiratory distress patients was introduced, and the model of calculating flow rates of medical oxygen system air source in emergency hospital was proposed. The cases were verified in a typical health emergency hospital that the developed calculation flow model of medical oxygen source met the demands of hospital oxygen. The outcomes provide a reference for the design and construction of medical oxygen in such health emergency hospitals.

A Review of High Flow Nasal Cannula Oxygen Therapy in Human and Veterinary Medicine

Respiratory distress is a common ailment in small animal medicine. Oxygen supplementation is a mainstay of initial therapy. High Flow Nasal Cannula Oxygen Therapy (HFNCOT) has become increasingly popular as a treatment modality in human medicine, and more recently in canine patients. These devices deliver high flow rates of heated and humidified oxygen at an adjustable fraction of inspired oxygen (FiO₂). This article reviews current literature in human patients on HFNCOT as well as studies that have evaluated its use in veterinary patients. A discussion of the respiratory physiology that is associated with respiratory distress, in addition to an overview of currently available oxygen supplementation modalities is provided. The physiologic benefits of HFNCOT are explained, as are technical aspects associated with its use. Recommendations on initial settings, maintenance therapy, and weaning are also described.

Airway management in the adult patient with COVID-19: High flow nasal oxygen or not? A summary of evidence and local expert opinion

The use of high flow nasal oxygen in the care of COVID-19-positive adult patients remains an area of contention. Early guidelines have discouraged the use of high flow nasal oxygen therapy in this setting due to the risk of viral spread to healthcare workers. However, there is the need to balance the relative risks of increased aerosol generation and virus transmission to healthcare workers against the role high flow nasal oxygen has in reducing hypoxaemia when managing the airway in high-risk patients during intubation or sedation procedures. The authors of this article undertook a narrative review to present results from several recent papers. Surrogate outcome studies suggest that the risk of high flow nasal oxygen in dispersing aerosol-sized particles is probably not as great as first perceived. Smoke laser-visualisation experiments and particle counter studies suggest that the generation and dispersion of bio-aerosols via high flow nasal oxygen with flow rates up to 60 l/min is similar to standard oxygen therapies. The risk appears to be similar to oxygen supplementation via a Hudson mask at 15 l/min and significantly less than low flow nasal prong oxygen 1-5 l/min, nasal continuous positive airway pressure with ill-fitting masks, bilevel positive airway pressure, or from a coughing patient. However, given the limited safety data, we recommend a cautious approach. For intubation in the COVID-positive or suspected COVID-positive patient we support the use of high flow nasal oxygen to extend time to desaturation in the at-risk groups, which include the morbidly obese, those with predicted difficult airways and patients with significant hypoxaemia, ensuring well-fitted high flow nasal oxygen prongs with staff wearing full personal protective equipment. For sedation cases, we support the use of high flow nasal oxygen when there is an elevated risk of hypoxaemia (e.g. bariatric endoscopy or prone-positioned procedures), but recommend securing the airway with a cuffed endotracheal tube for the longer duration procedures when theatre staff remain in close proximity to the upper airway, or considering the use of a surgical mask to reduce the risk of exhaled particle dispersion.

Noninvasive ventilation vs. high-flow nasal cannula oxygen for preoxygenation before intubation in patients with obesity: a post hoc analysis of a randomized controlled trial

BACKGROUND

Critically ill patients with obesity may have an increased risk of difficult intubation and subsequent severe hypoxemia. We hypothesized that pre-oxygenation with noninvasive ventilation before intubation as compared with high-flow nasal cannula oxygen may decrease the risk of severe hypoxemia in patients with obesity.

METHODS

Post hoc subgroup analysis of critically ill patients with obesity (body mass index ≥ 30 kg·m^-2) from a multicenter randomized controlled trial comparing preoxygenation with noninvasive ventilation and high-flow nasal oxygen before intubation of patients with acute hypoxemic respiratory failure (PaO₂/FiO₂ < 300 mm Hg). The primary outcome was the occurrence of severe hypoxemia (pulse oximetry < 80%) during the intubation procedure.

RESULTS

Among the 313 patients included in the original trial, 91 (29%) had obesity with a mean body mass index of 35 ± 5 kg·m^-2. Patients with obesity were more likely to experience an episode of severe hypoxemia during intubation procedure than patients without obesity: 34% (31/91) vs. 22% (49/222); difference, 12%; 95% CI 1 to 23%; P = 0.03. Among patients with obesity, 40 received preoxygenation with noninvasive ventilation and 51 with high-flow nasal oxygen. Severe hypoxemia occurred in 15 patients (37%) with noninvasive ventilation and 16 patients (31%) with high-flow nasal oxygen (difference, 6%; 95% CI - 13 to 25%; P = 0.54). The lowest pulse oximetry values during intubation procedure were 87% [interquartile range, 77-93] with noninvasive ventilation and 86% [78-92] with high-flow nasal oxygen (P = 0.98). After multivariable analysis, factors independently associated with severe hypoxemia in patients with obesity were intubation difficulty scale > 5 points and respiratory primary failure as reason for admission.

CONCLUSIONS

Patients with obesity and acute hypoxemic respiratory failure had an increased risk of severe hypoxemia during intubation procedure as compared to patients without obesity. However, preoxygenation with noninvasive ventilation may not reduce this risk compared with high-flow nasal oxygen. Trial registration Clinical trial number: NCT02668458 ( http://www.clinicaltrials.gov ).

Airway Management in the Critically Ill Patient

Purpose of Review

This paper will evaluate the recent literature and best practices in airway management in critically ill patients.

Recent Findings

Cardiac arrest remains a common complication of intubation in these high-risk patients. Patients with desaturation or peri-intubation hypotension are at high risk of cardiac arrest, and each of these complications have been reported in up to half of all intubations in critically ill patient populations.

Summary

There have been significant advances in preoxygenation and devices available for performing laryngoscopy and rescue oxygenation. However, the risk of cardiovascular collapse remains concerningly high with few studies to guide therapeutic maneuvers to reduce this risk.

Comparison of Oxygen Saturation Between Nasal High-Flow Oxygen and Conventional Nasal Cannula in Obese Patients Undergoing Dental Procedures With Deep Sedation: A Randomized Crossover Trial

PURPOSE

In anesthetic management, it is widely accepted that obese patients are more likely to suffer airway obstructions and reductions in arterial oxygen saturation (SpO₂). Therefore, it is important to take special measures to prevent oxygen desaturation during the deep sedation of obese patients. This clinical study examined whether the use of nasal high-flow systems (NHFS) keep higher SpO₂ and reduced hypoxemia than conventional nasal cannula during the deep sedation of obese patients with intellectual disabilities for dental treatment.

MATERIALS AND METHODS

Eighteen obese patients (body mass index: >25) with intellectual disabilities who underwent dental sedation were enrolled. In each case, sedation was induced using propofol and maintained at a bispectral index of 50 to 70. The subjects were randomly assigned to the control oxygen administration (5 L/min via a nasal cannula) or NHFS (40% O₂, 40 L/min, 37 °C) arm in alternate shifts as a crossover trial. The primary endpoint was the minimum SpO₂ value, and the incidence of hypoxemia during dental treatment was also evaluated.

RESULTS

The mean minimum SpO₂ value was significantly higher in the NHFS arm than in the control arm (95.8 ± 2.1 % vs 93.6 ± 4.1 %, P = 0.0052, 95% confidence interval: 0.608-3.947). Hypoxemic episodes (SpO₂: ≤94%) occurred 3 cases (16.7%) in the NHFS arm and 11 cases (61.1%) in the control arm (P = 0.0076, odds ratio: 0.127, 95% confidence interval 0.0324 - 0.630).

CONCLUSION

NHFS resulted in higher minimum SpO₂ and reduced hypoxemia than nasal cannula in obese patients during deep sedation for dental treatment.

Difficult Airway Management in Adult COVID-19 Patients: Statement by the Society of Airway Management

The COVID-19 disease, caused by Coronavirus SARS-CoV-2, often results in severe hypoxemia requiring airway management. Because SARS CoV-2 virus is spread via respiratory droplets, bag-mask ventilation, intubation, and extubation may place health care workers (HCW) at risk. While existing recommendations address airway management in patients with COVID-19, no guidance exists specifically for difficult airway management. Some strategies normally recommended for difficult airway management may not be ideal in the setting of COVID-19 infection. To address this issue the Society for Airway Management (SAM) created a task force to review existing literature and current Practice Guidelines for management of the difficult airway by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. SAM task force created recommendations for management of known or suspected difficult airway in the setting of known or suspected COVID-19 infection. The goal of the task force was to optimize successful airway management while minimizing exposure risk. Each member conducted a literature review on specific clinical practice section utilizing standard search engines (PubMed, Ovid, Google Scholar). Existing recommendations and evidence for difficult airway management in COVID-19 context were developed. Each specific recommendation was discussed among task force members and modified until unanimously approved by all task force members. Elements of AGREE Reporting Checklist for dissemination of clinical practice guidelines were utilized to develop this statement. Airway management in the COVID-19 patient increases HCW exposure risk. and difficult airway management often takes longer, may involve multiple procedures with aerosolization potential, strict adherence to personal protective equipment (PPE) protocols is mandatory to reduce risk to providers. When patient's airway risk assessment suggests awake tracheal intubation is an appropriate choice of technique, procedures that may cause increased aerosolization of secretions should be avoided. Optimal preoxygenation before induction with tight seal facemask may be performed to reduce risk of hypoxemia. Unless the patient is experiencing oxygen desaturation, positive pressure bag-mask ventilation after induction may be avoided to reduce aerosolization. For optimal intubating conditions, patients should be anesthetized with full muscle relaxation. Videolaryngoscopy is recommended as first-line strategy for airway management. If emergent invasive airway access is indicated, we recommend a surgical technique such as scalpel-bougie-tube, rather than an aerosolizing generating procedure, such as transtracheal jet ventilation. This statement represents recommendations by SAM task force for the difficult airway management of adults with COVID-19 with the goal to optimize successful airway management while minimizing the risk of clinician exposure.

Pre-oxygenation using high-flow nasal oxygen vs. tight facemask during rapid sequence induction

Pre-oxygenation using high-flow nasal oxygen can decrease the risk of desaturation during rapid sequence induction in patients undergoing emergency surgery. Previous studies were single-centre and often in limited settings. This randomised, international, multicentre trial compared high-flow nasal oxygen with standard facemask pre-oxygenation for rapid sequence induction in emergency surgery at all hours of the day and night. A total of 350 adult patients from six centres in Sweden and one in Switzerland undergoing emergency surgery where rapid sequence induction was required were included and randomly allocated to pre-oxygenation with 100% oxygen using high-flow nasal oxygen or a standard tight-fitting facemask. The primary outcome was the number of patients developing oxygen saturations <93% from the start of pre-oxygenation until 1 min after tracheal intubation. Data from 349 of 350 patients who entered the study were analysed (174 in the high-flow nasal oxygen group and 175 in the facemask group). No difference was detected in the number of patients desaturating <93%, five (2.9%) vs. six (3.4%) patients in the high-flow nasal oxygen and facemask group, respectively (p = 0.77). The risk of desaturation was not increased during on-call hours. No difference was seen in end-tidal carbon dioxide levels in the first breath after tracheal intubation or in the number of patients with signs of regurgitation between groups. These results confirm that high-flow nasal oxygen maintains adequate oxygen levels during pre-oxygenation for rapid sequence induction.

High-flow therapy: physiological effects and clinical applications

Humidified high-flow therapy (HFT) is a noninvasive respiratory therapy, typically delivered through a nasal cannula interface, which delivers a stable fraction of inspired oxygen (F_IO2) at flow rates of up to 60 L·min⁻¹. It is well-tolerated, simple to set up and ideally applied at 37°C to permit optimal humidification of inspired gas. Flow rate and F_IO2 should be selected based on patients' inspiratory effort and severity of hypoxaemia. HFT yields beneficial physiological effects, including improved mucociliary clearance, enhanced dead space washout and optimisation of pulmonary mechanics. Robust evidence supports its application in the critical care setting (treatment of acute hypoxaemic respiratory failure and prevention of post-extubation respiratory failure) and emerging data supports HFT use during bronchoscopy, intubation and breaks from noninvasive ventilation or continuous positive airway pressure. There are limited data on HFT use in patients with hypercapnic respiratory failure, as an adjunct to pulmonary rehabilitation and in the palliative care setting, and further research is needed to validate the findings of small studies. The COVID-19 pandemic raises questions regarding HFT efficacy in COVID-19-related hypoxaemic respiratory failure and concerns regarding aerosolisation of respiratory droplets. Clinical trials are ongoing and healthcare professionals should implement strict precautions to mitigate the risk of nosocomial transmission.

Humidified high-flow therapy is a well-tolerated method of delivering a stable F_IO2 at flow rates up to 60 L/min. It improves secretion clearance, dead space washout and pulmonary mechanics and is an effective treatment in hypoxaemic respiratory failurehttps://bit.ly/35Hvjrj

Comparison of hypoxemia, intubation procedure, and complications for non-invasive ventilation against high-flow nasal cannula oxygen therapy for patients with acute hypoxemic respiratory failure: a non-randomized retrospective analysis for effectiveness and safety (NIVaHIC-aHRF)

BACKGROUND

Optimization of preoxygenation procedure can help to secure the method of intubation by reducing the risks of severe hypoxemia and other problems. There is confusion for efficacy of non-invasive ventilation compared to high-flow oxygen therapy regarding occurrence of severe hypoxemia during the intubation procedure. The purpose of the study was to compare the difference between noninvasive ventilation and high flow oxygen therapy to prevent desaturation during laryngoscopy.

METHODS

Patients underwent high-flow nasal cannula oxygen therapy (HCO cohort, n = 161) or non-invasive ventilation procedure (NIV cohort, n = 154) for oxygenation and ventilation due to acute hypoxemic respiratory failure in the intensive care unit. Data before preoxygenation, preoxygenation, intubation, laryngoscopy, and complications of patients due to tracheal intubation were retrospectively collected and analyzed.

RESULTS

There was no difference between both cohorts for the demographical and clinical conditions of the patients before preoxygenation (p > 0.05 for all parameters), numbers of patients with severe hypoxia during the intubation procedure (35 vs. 45, p = 0.303), the time duration of laryngoscopy (p = 0.847), number of laryngoscopies attempts (p = 0.804), and immediate and late complications during the intubation procedure. The values of pulse oximetry were reported higher for patients of NIV cohort than those of HCO cohort during preoxygenation. Fewer numbers of patients were reported with severe hypoxia among patients of the NIV cohort than those of the HCO cohort (24 vs., 40, p = 0.042) who have moderate-to-severe hypoxemia (partial pressure of arterial oxygen to fraction of inspired oxygen ratio ≤ 200 mmHg) before preoxygenation. The most common complications were hypertension, pulmonary aspiration, and increased 30-day mortality.

CONCLUSIONS

When compared, there was no difference between non-invasive ventilation technique and high-flow oxygen therapy to minimize severe hypoxia prior to laryngoscopy and endotracheal intubation in patients with acute respiratory failure.

Endotracheal Intubation in the Pharmaceutical-Poisoned Patient: a Narrative Review of the Literature

INTRODUCTION

Endotracheal intubation (ETI) is an essential component of the supportive care provided to the critically ill patient with pharmaceutical poisoning; however, specific nuances surrounding intubation including techniques and complications in the context of pharmaceutical poisoning have not been well elucidated.

DISCUSSION

A search of the available literature on ETI in pharmaceutical-poisoned patients was undertaken using Medline, ERIC, Cochrane database, and PsycINFO using the following MeSH and keyword terms: ("toxicology" OR "poisons" OR "drug overdose" OR "poisoning") AND ("intubation, intratracheal" OR "intubation, endotracheal" OR "airway management" OR "respiration, artificial"). A hand-search was also performed when the literature in the above search required additional conceptual clarification, including using the "Similar Articles" feature of PubMed, along with reviewing articles' reference lists that discussed intubation in the context of a poisoning scenario. Articles with any discussion around the ETI process in the context of a pharmaceutical poisoning were then included. Intubation may be performed in patients poisoned with pharmaceuticals in the context of both single and multiple organ dysfunction including central and peripheral nervous system, pulmonary, or cardiovascular toxicity with hemodynamic instability, or localized effects resulting in mechanical airway obstruction. Certain classes of poisonings may require modifications to the standard rapid sequence induction airway management algorithm.

CONCLUSIONS

ETI is a key component of the supportive care provided to the patient poisoned by a pharmaceutical agent. Clinicians should be aware of the spectrum of toxicities that can necessitate intubation, as well as airway management nuances that are specific to various poisoning presentations.

Canadian Airway Focus Group updated consensus-based recommendations for management of the difficult airway: part 2. Planning and implementing safe management of the patient with an anticipated difficult airway

PURPOSE

Since the last Canadian Airway Focus Group (CAFG) guidelines were published in 2013, the published airway management literature has expanded substantially. The CAFG therefore re-convened to examine this literature and update practice recommendations. This second of two articles addresses airway evaluation, decision-making, and safe implementation of an airway management strategy when difficulty is anticipated.

SOURCE

Canadian Airway Focus Group members, including anesthesia, emergency medicine, and critical care physicians were assigned topics to search. Searches were run in the Medline, EMBASE, Cochrane Central Register of Controlled Trials, and CINAHL databases. Results were presented to the group and discussed during video conferences every two weeks from April 2018 to July 2020. These CAFG recommendations are based on the best available published evidence. Where high-quality evidence is lacking, statements are based on group consensus.

FINDINGS AND KEY RECOMMENDATIONS

Prior to airway management, a documented strategy should be formulated for every patient, based on airway evaluation. Bedside examination should seek predictors of difficulty with face-mask ventilation (FMV), tracheal intubation using video- or direct laryngoscopy (VL or DL), supraglottic airway use, as well as emergency front of neck airway access. Patient physiology and contextual issues should also be assessed. Predicted difficulty should prompt careful decision-making on how most safely to proceed with airway management. Awake tracheal intubation may provide an extra margin of safety when impossible VL or DL is predicted, when difficulty is predicted with more than one mode of airway management (e.g., tracheal intubation and FMV), or when predicted difficulty coincides with significant physiologic or contextual issues. If managing the patient after the induction of general anesthesia despite predicted difficulty, team briefing should include triggers for moving from one technique to the next, expert assistance should be sourced, and required equipment should be present. Unanticipated difficulty with airway management can always occur, so the airway manager should have a strategy for difficulty occurring in every patient, and the institution must make difficult airway equipment readily available. Tracheal extubation of the at-risk patient must also be carefully planned, including assessment of the patient's tolerance for withdrawal of airway support and whether re-intubation might be difficult.

Evaluating the ventilatory effect of transnasal humidified rapid insufflation ventilatory exchange in apnoeic small children with two different oxygen flow rates: a randomised controlled trial. Anaesthesia 2020;76:924-932. [PMID: 33351194 DOI: 10.1111/anae.15335]

Transnasal humidified rapid insufflation ventilatory exchange prolongs safe apnoeic oxygenation time in children. In adults, transnasal humidified rapid insufflation ventilatory exchange is reported to have a ventilatory effect with PaCO₂ levels increasing less rapidly than without it. This ventilatory effect has yet to be reproduced in children. In this non-inferiority study, we tested the hypothesis that children weighing 10-15 kg exhibit no difference in carbon dioxide clearance when comparing two different high-flow nasal therapy flow rates during a 10-min apnoea period. Following standardised induction of anaesthesia including neuromuscular blockade, patients were randomly allocated to high-flow nasal therapy of 100% oxygen at 2 or 4 l.kg^-1 .min^-1 . Airway patency was ensured by continuous jaw thrust. The study intervention was terminated for safety reasons when SpO₂ values dropped < 95%, or transcutaneous carbon dioxide levels rose > 9.3 kPa, or near-infrared spectroscopy values dropped > 20% from their baseline values, or after an apnoeic period of 10 min. Fifteen patients were included in each group. In the 2 l.kg^-1 .min^-1 group, mean (SD) transcutaneous carbon dioxide increase was 0.46 (0.11) kPa.min^-1 , while in the 4 l.kg^-1 .min^-1 group it was 0.46 (0.12) kPa.min^-1 . The upper limit of a one-sided 95%CI for the difference between groups was 0.07 kPa.min^-1 , lower than the predefined non-inferiority margin of 0.147 kPa.min^-1 (p = 0.001). The lower flow rate of 2 l.kg^-1 .min^-1 was non-inferior to 4 l.kg^-1 .min^-1 relative to the transcutaneous carbon dioxide increase. In conclusion, an additional ventilatory effect of either 2 or 4 l.kg^-1 .min^-1 high-flow nasal therapy in apnoeic children weighing 10-15 kg appears to be absent.

Transnasal Humidified Rapid Insufflation Ventilatory Exchange With Nasopharyngeal Airway Facilitates Apneic Oxygenation: A Randomized Clinical Noninferiority Trial

Background: Transnasal humidified rapid insufflation ventilatory exchange (THRIVE) was used to extend the safe apnea time. However, THRIVE is only effective in patients with airway opening. Nasopharyngeal airway (NPA) is a simple device that can help to keep airway opening. This study aimed to investigate the noninferiority of NPA to jaw thrust for airway opening during anesthesia-induced apnea. Methods: This was a prospective randomized single-blinded noninferiority clinical trial on the use of THRIVE in patients with anesthesia-induced apnea. The participants were randomly allocated to receive NPA or jaw thrust. The primary outcomes were PaO₂ and PaCO₂ at 20 min after apnea, with noninferiority margin criteria of -6.67 and 0.67 kPa, respectively. Results: A total of 123 patients completed the trial: 61 in the NPA group and 62 in the jaw thrust group. PaO₂ at 20 min after apnea was 42.9 ± 14.0 kPa in the NPA group and 42.7 ± 13.6 kPa in the jaw thrust group. The difference between these two means was 0.25 kPa (95% CI, -3.87 to 4.37 kPa). Since the lower boundary of the 95% CI was > -6.67 kPa, noninferiority was established because higher PO₂ is better. PaCO₂ at 20 min after apnea was 10.74 ± 1.09 kPa in the NPA group and 10.54 ± 1.18 kPa in the jaw thrust group. The difference between the two means was 0.19 kPa (95% CI, -0.14 to 0.53 kPa). Since the upper boundary of the 95% CI was <0.67 kPa, noninferiority was established because lower PCO₂ is better. No patient had a SpO₂ < 90% during apnea. Conclusion: When THRIVE was applied during anesthesia-induced apnea, NPA placement kept airway opening and was noninferior to jaw thrust in terms of its effects on PaO₂ and PaCO₂ at 20 min after apnea. Clinical Trial Registration: ClinicalTrials.gov (NCT03741998).

The efficacy of high flow nasal oxygenation for maintaining maternal oxygenation during rapid sequence induction in pregnancy: A prospective randomised clinical trial

BACKGROUND

High-flow nasal oxygenation (HFNO) for pre-oxygenation in rapid sequence induction (RSI) has only been assessed in volunteer parturients without intubation.

OBJECTIVES

To evaluate the efficacy of HFNO in comparison with the conventional facemask for oxygenation during RSI for caesarean section under general anaesthesia.

SETTING

Operating room in a tertiary hospital.

DESIGN

Prospective randomised, controlled study.

PARTICIPANTS

Thirty-four healthy parturients undergoing general anaesthesia for caesarean section.

INTERVENTIONS

Parturients were randomly assigned to HFNO or standard facemask (SFM) group.

MAIN OUTCOME MEASURES

The primary outcome measure was the PaO2 immediately after intubation. Secondary outcomes included lowest saturation throughout the intubation procedure, end-tidal oxygen concentration (EtO2) on commencing ventilation, blood gas analysis (pH, PaCO2), fetal outcomes and intubation-related adverse events.

RESULTS

PaO2 in the HFNO group was significantly higher than that in SFM group (441.41 ± 46.73 mmHg versus 328.71 ± 72.80 mmHg, P < 0.0001). The EtO2 concentration in the HFNO group was higher than that in the SFM group (86.71 ± 4.12% versus 76.94 ± 7.74%, P < 0.0001). Compared to baseline, PaCO2 immediately after intubation also increased significantly in both groups (HFNO group: 30.87 ± 2.50 mmHg versus 38.28 ± 3.18 mmHg; SFM group: 29.82 ± 2.57 mmHg versus 38.05 ± 5.76 mmHg, P < 0.0001), but there was no difference in PaCO2 between the two groups. There was no difference in lowest saturation, intubation times, duration of apnoea, pH value or fetal outcomes.

CONCLUSIONS

Compared with SFM, HFNO provided a higher PaO2 and EtO2 immediately after intubation in parturients. HFNO is safe as a method of oxygenation during RSI in parturients undergoing general anaesthesia for caesarean section.

TRIAL REGISTRATION

Clinical trial ChiCTR1900023121.

The Effectiveness of High-Flow Nasal Oxygen During the Intraoperative Period: A Systematic Review and Meta-analysis

BACKGROUND

High-flow nasal oxygen (HFNO) is increasingly being used in intensive care units for management of hypoxemia and respiratory failure. However, the effectiveness of HFNO for preventing hypoxemia in the intraoperative period is unclear. The purpose of this systematic review was to compare patient oxygenation and end-tidal CO2 (EtCO2), between HFNO and conventional oxygenation, during the intraoperative period in surgical patients.

METHODS

Standard databases were searched from inception to February 2020. Studies involving intraoperative use of HFNO with 1 of the 4 outcomes: (1) oxygen (O2) desaturation, (2) minimum O2 saturation, (3) safe apnea time, or (4) EtCO2 were included. Intraoperative period was divided into 2 phases: at induction with general anesthesia and during surgical procedure under sedation without tracheal intubation.

RESULTS

Eight randomized controlled trials (RCTs; 4 induction, 4 procedure, 2314 patients) were included for systematic review and meta-analyses. We found the risk of intraoperative O2 desaturation was lower in HFNO versus conventional oxygenation control group; at induction with an odds ratio (OR; 95% confidence interval [CI]) of 0.06 (0.01-0.59, P = .02), and during procedure, OR (95% CI) of 0.09 (0.05-0.18; P < .001). The minimum O2 saturation was higher in HFNO versus conventional oxygenation; at induction by a mean difference (MD) (95% CI) of 5.1% (3.3-6.9; P < .001), and during procedure, by a MD (95% CI) of 4.0% (1.8-6.2; P < .001). Safe apnea time at induction was longer in HFNO versus conventional oxygenation by a MD (95% CI) of 33.4 seconds (16.8-50.1; P < .001). EtCO2 at induction was not significantly different between HFNO and conventional oxygenation groups.

CONCLUSIONS

This systematic review and meta-analysis show that, in the intraoperative setting, HFNO compared to conventional oxygenation reduces the risk of O2 desaturation, increases minimum O2 saturation, and safe apnea time. HFNO should be considered for anesthesia induction and during surgical procedures under sedation without tracheal intubation in patients at higher risk of hypoxemia.

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.

High-flow nasal cannula therapy as apneic oxygenation during endotracheal intubation in critically ill patients in the intensive care unit: a systematic review and meta-analysis

We conducted a systematic review and meta-analysis to assess the clinical efficacy of high-flow nasal cannula (HFNC) therapy as apneic oxygenation in critically ill patients who require endotracheal intubation in the intensive care unit (ICU). This systematic review and meta-analysis included six randomized controlled trials and a prospective study identified in PubMed, Embase, Cochrane Library, and the Web of Science until August 18, 2019. In this meta-analysis including 956 participants, HFNC was noninferior to standard of care during endotracheal intubation regarding incidence of severe hypoxemia, mean lowest oxygen saturation, and in-hospital mortality. HFNC significantly shortened the ICU stay by a mean of 1.8 days. In linear meta-regression interaction analysis, the risk ratio of severe hypoxemia decreased with increasing baseline partial oxygen pressure (PaO2) to fraction of inspired oxygen (FiO2) ratio. In subgroup analysis, HFNC significantly reduced the incidence of severe hypoxemia during endotracheal intubation in patients with mild hypoxemia (PaO2/FiO2> 200 mmHg; risk difference, -0.06; 95% confidence interval, -0.12 to -0.01; number needed to treat = 16.7). In conclusion, HFNC was noninferior to standard of care for oxygen delivery during endotracheal intubation and was associated with a significantly shorter ICU stay. The beneficial effect of HFNC in reducing the incidence of severe hypoxemia was observed in patients with mild hypoxemia.

High-flow nasal oxygenation versus standard oxygenation for gastrointestinal endoscopy with sedation. The prospective multicentre randomised controlled ODEPHI study protocol

INTRODUCTION

Hypoxaemia is a major complication during gastrointestinal endoscopy (GIE) procedures (upper/lower) when performed under deep sedation in the procedure room. Standard oxygen therapy (SOT) is used to prevent hypoxaemia. Data suggest that risk factors for hypoxaemia under deep sedation during GIE are obstructive sleep apnoea syndrome, a body mass index above 30 kg/m², high blood pressure, diabetes, heart disease, age over 60 years old, high American Society of Anesthesiologists physical status class and the association of upper and lower GIE. High-flow nasal oxygenation (HFNO) may potentially improve oxygenation during GIE under deep sedation. We hypothesised that HFNO could decrease the incidence of hypoxaemia in comparison with SOT.

METHODS AND ANALYSIS

The ODEPHI (High-flow nasal oxygenation versus standard oxygenation for gastrointestinal endoscopy with sedation. The prospective multicentre randomised controlled) study is a multicentre randomised controlled trial comparing HFNO to SOT during GIE (upper and/or lower) under deep sedation administered by anaesthesiologists in the procedure room. Three hundred and eighty patients will be randomised with a 1:1 ratio in two parallel groups.The primary outcome is the occurrence of hypoxaemia, defined by a pulse oximetry measurement of peripheral capillary oxygen saturation (SpO₂) below or equal to 92% during the GIE procedure. Secondary outcomes include prolonged hypoxaemia, severe hypoxaemia, need for manoeuvres to maintain upper airway patency and other adverse events.

ETHICS AND DISSEMINATION

This study has been approved by the ethics committee (CPP Sud Est Paris V, France), and patients are included after informed consent. The results will be submitted for publication in peer-reviewed journals. As provided for by French law, patients participating in the study are informed that they have the possibility to ask the investigators, once the study is completed, to be informed of the overall results of the study. Thus, a summary of the results will be sent by post to the participants on request.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT03829293).

Nasal High Flow Use in COPD Patients with Hypercapnic Respiratory Failure: Treatment Algorithm & Review of the Literature

Nasal high flow (NHF) therapy has recently gained attention as a new respiratory support system and is increasingly being utilized in every day clinical practice. Recent studies suggest that it may also be effective in patients with hypercapnia and suggest NHF as a possible alternative for patients who cannot tolerate standard noninvasive ventilation. The present review discusses the mechanisms of action that make NHF potentially suitable for chronic obstructive pulmonary disease (COPD) patients and evaluates the current evidence of NHF use for treatment of stable hypercapnic COPD patients as well as acute hypercapnic exacerbation of COPD. An algorithm is also proposed for the clinical application of NHF in patients with acute hypercapnic exacerbation of COPD, based on current literature.

Compared Efficacy of Four Preoxygenation Methods for Intubation in the ICU: Retrospective Analysis of McGrath Mac Videolaryngoscope Versus Macintosh Laryngoscope (MACMAN) Trial Data

OBJECTIVES

Severe hypoxemia is the most common serious adverse event during endotracheal intubation. Preoxygenation is performed routinely as a preventive measure. The relative efficacy of the various available preoxygenation devices is unclear. Here, our objective was to assess associations between preoxygenation devices and pulse oximetry values during endotracheal intubation.

DESIGN

Post hoc analysis of data from a multicenter randomized controlled superiority trial (McGrath Mac Videolaryngoscope Versus Macintosh Laryngoscope [MACMAN]) comparing videolaryngoscopy to Macintosh laryngoscopy for endotracheal intubation in critical care.

SETTING

Seven French ICUs.

PATIENTS

Three-hundred nineteen of the 371 critically ill adults requiring endotracheal intubation who were included in the MACMAN trial.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Minimal pulse oximetry value during endotracheal intubation was the primary endpoint. We also sought risk factors for pulse oximetry below 90%. Of 319 patients, 157 (49%) had bag-valve-mask, 71 (22%) noninvasive ventilation, 71 (22%) non-rebreathing mask, and 20 (7%) high-flow nasal oxygen for preoxygenation. Factors independently associated with minimal pulse oximetry value were the Simplified Acute Physiology Score II severity score (p = 0.03), baseline pulse oximetry (p < 0.001), baseline PaO2/FIO2 ratio (p = 0.02), and number of laryngoscopies (p = 0.001). The only independent predictors of pulse oximetry less than 90% were baseline pulse oximetry (odds ratio, 0.71; 95% CI, 0.64-0.79; p < 0.001) and preoxygenation device: with bag-valve-mask as the reference, odds ratios were 1.10 (95% CI, 0.25-4.92) with non-rebreathing mask, 0.10 (95% CI, 0.01-0.80) with noninvasive ventilation, and 5.75 (95% CI, 1.15-28.75) with high-flow nasal oxygen.

CONCLUSIONS

Our data suggest that the main determinants of hypoxemia during endotracheal intubation may be related to critical illness severity and to preexisting hypoxemia. The differences across preoxygenation methods suggest that noninvasive ventilation may deserve preference in patients with marked hypoxemia before endotracheal intubation. Ongoing studies will provide further clarification about the optimal preoxygenation method for endotracheal intubation in critically ill patients.

Apneic Oxygenation As a Quality Improvement Intervention in an Academic PICU

OBJECTIVES

To evaluate if the use of apneic oxygenation during tracheal intubation in children is feasible and would decrease the occurrence of oxygen desaturation.

DESIGN

Prospective pre/post observational study.

SETTING

A large single-center noncardiac PICU in North America.

PATIENTS

All patients less than 18 years old who underwent primary tracheal intubation from August 1, 2014, to September 30, 2018.

INTERVENTIONS

Implementation of apneic oxygenation for all primary tracheal intubation as quality improvement.

MEASUREMENTS AND MAIN RESULTS

Total of 1,373 tracheal intubations (661 preimplementation and 712 postimplementation) took place during study period. Within 2 months, apneic oxygenation use reached to predefined adherence threshold (> 80% of primary tracheal intubations) after implementation and sustained at greater than 70% level throughout the postimplementation. Between the preimplementation and postimplementation, no significant differences were observed in patient demographics, difficult airway features, or providers. Respiratory and procedural indications were more common during preintervention. Video laryngoscopy devices were used more often during the postimplementation (pre 5% vs post 75%; p < 0.001). Moderate oxygen desaturation less than 80% were observed in fewer tracheal intubations after apneic oxygenation implementation (pre 15.4% vs post 11.8%; p = 0.049); severe oxygen desaturation less than 70% was also observed in fewer tracheal intubations after implementation (pre 10.4% vs post 7.2%; p = 0.032). Hemodynamic tracheal intubation associated events (i.e., cardiac arrests, hypotension, dysrhythmia) were unchanged (pre 3.2% vs post 2.0%; p = 0.155). Multivariable analyses showed apneic oxygenation implementation was significantly associated with a decrease in moderate desaturation less than 80% (adjusted odds ratio, 0.55; 95% CI, 0.34-0.88) and with severe desaturation less than 70% (adjusted odds ratio, 0.54; 95% CI, 0.31-0.96) while adjusting for tracheal intubation indications and device.

CONCLUSIONS

Implementation of apneic oxygenation in PICU was feasible, and was associated with significant reduction in moderate and severe oxygen desaturation. Use of apneic oxygenation should be considered when intubating critically ill children.