Effectiveness of trans-nasal humidified rapid insufflation ventilatory exchange compared with standard facemask oxygenation for pre- and apneic oxygenation during anesthesia induction: A meta-analysis based on randomized controlled trials

PURPOSE

To further identify the effectiveness of trans-nasal humidified rapid insufflation ventilatory exchange (THRIVE) for pre- and apneic oxygenation during the anesthesia induction by comparison to facemask ventilation (FMV) based on current available evidence.

METHODS

Medline, EMBASE, Web of Science, Cochrane Library and CNKI databases were searched from inception to December 22, 2023 for available randomized controlled trials (RCTs). Primary outcomes were PaO2 and PaCO2 after intubation and safe apnoea time. Secondary outcomes included the O2 desaturation, end expiratory carbon dioxide (EtCO2) and complications. The effect measures for continuous and categorical outcomes were separately the mean difference (MD) and relative risk (RR) with 95% confidence interval.

RESULTS

Twelve RCTs with 403 patients in the THRIVE group and 401 patients in th FMV group were included. Pooled results demonstrated that the PaO2 after intubation was significantly higher (MD = 82.90mmHg, 95% CI: 12.25~153.54mmHg, P = 0.02) and safe apnoea time (MD = 103.81s, 95% CI: 42.07~165.56s, P = 0.001) was longer in the THRIVE group. Besides, the incidence rate of O2 desaturation (RR = 0.28, 95% CI: 0.12-0.66, P = 0.004) and gastric insufflation (RR = 0.26, 95% CI: 0.13-0.49, P<0.001) was significantly lower in the THRIVE group.

CONCLUSION

Based on current evidence, THRIVE manifested better effectiveness representing as improved oxygenation, prolonged safe apnoea time and decreased risk of complications compared to standard FMV in surgical patients. Therefore, THRIVE could be served as a novel and valuable oxygenation technology for patients during anesthesia induction.

Trans-nasal Humidified Rapid Insufflation Ventilatory Exchange (THRIVE) and its Utility in Otolaryngology, Head and Neck Surgery: A Literature Review

High-flow nasal oxygen (HFNO) therapy is extensively used in critical care units for spontaneously breathing patients. Trans-nasal humidified rapid insufflation ventilatory exchange (THRIVE) is a method of apnoeic oxygenation with continuous nasal delivery of warmed, humidified oxygen at high-flow rates up to 70L/min. THRIVE extends the apnoeic window before desaturation occurs so that tubeless anaesthesia is possible. The advent of THRIVE has had a monumental impact on anaesthetic practice, with a diverse range of clinical applications and it has been incorporated into difficult airway guidelines. THRIVE has many applications in otolaryngology and head and neck surgery. It is used as a pre-oxygenation tool during induction in both anticipated and unanticipated difficult airway scenarios and as a method of oxygenation for tubeless anaesthesia in elective laryngotracheal and hypopharyngeal surgeries and during emergence from anaesthesia. In this scoping review of the literature, we aim to provide an overview on the utility of THRIVE in otolaryngology, including the underlying physiologic principles, current indications and limitations, and its feasibility and safety in different surgical contexts and specific population groups.

Trans-nasal humidified rapid insufflation ventilatory exchange (THRIVE) in neuroanesthesia practice: A review

Respiratory management is an important aspect of care in neuroanesthesia practice for neurosurgical patients. A wide variety of procedures are performed under sedation in the neurosurgical population, and maintaining oxygenation is of paramount importance during these procedures. The high-flow oxygen devices improve arterial oxygenation by providing higher inspiratory oxygen concentration and maintaining higher dynamic positive airway pressure. These devices have gained importance during the recent years with regard to enhancing patient safety. This narrative review focuses on the role of trans-nasal humidified rapid insufflation ventilatory exchange (THRIVE) and high-flow nasal oxygenation (HFNO) techniques in the neuroanesthesia practice and electroconvulsive therapy.

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.

Transnasal Humidified Rapid-Insufflation Ventilatory Exchange Versus Conventional Facemask Breathing for Preoxygenation During Rapid Sequence Induction

INTRODUCTION

Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE), if used for pre-oxygenation and apnoeic oxygenation, has the propensity to extend the safe apnoea time and thereby decrease the incidence of desaturation during rapid sequence induction (RSI) for emergency surgeries. Hence, we proposed to evaluate the comparative efficacy of pre-oxygenation with the use of conventional facemask breathing versus THRIVE during RSI in patients undergoing general anaesthesia (GA) for emergency surgeries.

MATERIALS AND METHODS

Eighty patients undergoing RSI under GA for emergency abdominopelvic surgery were divided randomly into two groups. Patients were preoxygenated for three minutes with 100% oxygen via either a high-flow nasal cannula at a flow of 60 L/minute using THRIVE or a tightly-held, snuggly-fitting facemask at a flow of 12L/minute using a circle system. RSI was administered followed by laryngoscopy and endotracheal intubation. Arterial partial pressure of oxygen (PaO2) measured immediately after successful endotracheal intubation was our primary outcome. The lowest peripheral oxygen saturation (SpO2), apnoea time, number of attempts at laryngoscopy, use of any rescue manoeuvres, and any adverse event were also recorded. Data thus collected were statistically analysed.

RESULTS

No statistically significant difference in PaO2 value was observed after successful intubation, lowest SpO2, apnoea time, number of attempts at laryngoscopy, use of any rescue manoeuvres, and adverse event between both the groups (p>0.05).

CONCLUSION

We conclude that though not superior to conventional facemasks, THRIVE is a safe, practicable, and efficient pre-oxygenation tool during RSI of GA for patients undergoing emergency surgeries.

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).

Preoxygenation with standard facemask combining apnoeic oxygenation using high flow nasal cannula versuss standard facemask alone in patients with and without obesity: the OPTIMASK international study

BACKGROUND

Combining oxygen facemask with apnoeic oxygenation using high-flow-nasal-oxygen (HFNO) for preoxygenation in the operating room has not been studied against standard oxygen facemask alone. We hypothesized that facemask-alone would be associated with lower levels of lowest end-tidal oxygen (EtO2) within 2 min after intubation in comparison with facemask combined with HFNO.

METHODS

In an international prospective before-after multicentre study, we included adult patients intubated in the operating room from September 2022 to December 2022. In the before period, preoxygenation was performed with facemask-alone, which was removed during laryngoscopy. In the after period, facemask combined with HFNO was used for preoxygenation and HFNO for apnoeic oxygenation during laryngoscopy. HFNO was maintained throughout intubation. The primary outcome was the lowest EtO2 within 2 min after intubation. The secondary outcome was SpO2 ≤ 95% within 2 min after intubation. Subgroup analyses were performed in patients without and with obesity. This study was registered 10 August 2022 with ClinicalTrials.gov, number NCT05495841.

RESULTS

A total of 450 intubations were evaluated, 233 with facemask-alone and 217 with facemask combined with HFNO. In all patients, the lowest EtO2 within 2 min after intubation was significantly lower with facemask-alone than with facemask combined with HFNO, 89 (85-92)% vs 91 (88-93)%, respectively (mean difference - 2.20(- 3.21 to - 1.18), p < 0.001). In patients with obesity, similar results were found [87(82-91)% vs 90(88-92)%, p = 0.004]; as in patients without obesity [90(86-92)% vs 91(89-93)%, p = 0.001)]. SpO2 ≤ 95% was more frequent with facemask-alone (14/232, 6%) than with facemask combined with HFNO (2/215, 1%, p = 0.004). No severe adverse events were recorded.

CONCLUSIONS

Combining facemask with HFNO for preoxygenation and apnoeic oxygenation was associated with increased levels of lowest EtO2 within 2 min after intubation and less desaturation.

Effect of High-Flow Nasal Oxygenation on Gastric Insufflation in Patients Undergoing Laryngeal Microsurgery under Tubeless General Anesthesia with Neuromuscular Blockade

BACKGROUND

High-flow nasal oxygenation is an oxygen delivery method by which high concentrations of heated humidified oxygen are supplied via the nasal cavity. This study aimed to investigate the effect of high-flow nasal oxygenation on gastric volume change in adult patients undergoing laryngeal microsurgery under tubeless general anesthesia with neuromuscular blockade.

METHODS

Patients aged 19-80 years with an American Society of Anesthesiologists physical status 1 or 2 who were scheduled to undergo laryngoscopic surgery under general anesthesia were recruited. Patients received high-flow nasal oxygenation therapy at 70 L/min during surgery under general anesthesia with neuromuscular blockade. The cross-sectional area of the gastric antrum was measured via ultrasound in the right lateral position before and after high-flow nasal oxygenation, and the gastric volume was calculated. The duration of apnea, i.e., the duration of administration of high-flow nasal oxygenation in the paralyzed state, was also recorded.

RESULTS

Of the 45 patients enrolled, 44 completed the study. There were no significant differences in the antral cross-sectional area in the right lateral position, gastric volume, and gastric volume per kg between before and after high-flow nasal oxygenation application. The median duration of apnea was 15 (interquartile range, 14-22) min.

CONCLUSION

High-flow nasal oxygenation at 70 L/min during apnea with the mouth open did not influence the gastric volume in patients undergoing laryngeal microsurgery under tubeless general anesthesia with neuromuscular blockade.

High-Flow Nasal Oxygenation and Its Applicability in COVID Patients

High-flow nasal oxygenation (HFNO) is a type of oxygen therapy that provides humidified and heated oxygen through a nasal cannula at much higher flow rates than standard oxygen therapy, while also allowing control over the fraction of inspired oxygen (FIO₂). Compared to standard oxygen therapy, it is much more comfortable for the patient and seems to alleviate most of the problems associated with standard oxygen therapy, such as dry nose, dry throat and nasal pain. It also provides a variety of benefits that can reduce the incidence of escalating treatment and initiating mechanical ventilation in COVID patients with acute hypoxemic respiratory failure (AHRF). This article provides an overview of HFNO and its current applications in COVID patients during the pandemic.

Ease and comfort of pre-oxygenation with high-flow nasal oxygen cannulae vs. facemask: a randomised controlled trial

The Difficult Airway Society recommends that all patients should be pre-oxygenated before the induction of general anaesthesia, but this may not always be easy or comfortable and anaesthesia may often be induced without full pre-oxygenation. We tested the hypothesis that high-flow nasal oxygen cannulae would be easier and more comfortable than facemasks for pre-oxygenation. We randomly allocated 199 patients undergoing elective surgery aged ≥ 10 years to pre-oxygenation using either high-flow nasal oxygen or facemask. Ease and comfort were assessed by anaesthetists and patients on 10-cm visual analogue scale and six-point smiley face scale, respectively. Secondary endpoints included end-tidal oxygen fraction after securing a definitive airway and time to secure an airway. A mean difference (95%CI) between groups in ratings of -0.76 (-1.25 to -0.27) cm for ease of use (p = 0.003) and -0.45 (-0.75 to -0.13) points for comfort (p = 0.006), both favoured high-flow nasal oxygen. A mean difference (95%CI) between groups in end-tidal oxygen fraction of 3.89% (2.41-5.37%) after securing a definitive airway also favoured high-flow nasal oxygen (p < 0.001). There was no significant difference between groups in the number of patients with hypoxaemia (S_p O₂  < 90%) or severe hypoxaemia (S_p O₂  < 85%) lasting ≥ 1 min or ≥ 2 min; in the proportion of patients with an end-tidal oxygen fraction < 87% in the first 5 min after tracheal intubation (52.2% vs. 58.9% in facemask and high-flow nasal oxygen groups, respectively; p = 0.31); or in time taken to secure an airway (11.6 vs. 12.2 min in facemask and high-flow nasal oxygen groups, respectively; p = 0.65). In conclusion, we found pre-oxygenation with high-flow nasal oxygen to be easier for anaesthetists and more comfortable for patients than pre-oxygenation with a facemask, with no clinically relevant differences in end-tidal oxygen fraction after securing a definitive airway or time to secure an airway. The differences in ease and comfort were modest.

Comparison of Transnasal Humidified Rapid-Insufflation Ventilatory Exchange and Facemasks in Preoxygenation: A Systematic Review and Meta-Analysis

Background

Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) has received increasing attention and application as an effective noninvasive mode of ventilation in the treatment of clinical anesthesia and critically ill patients. The conclusions reached in clinical studies of THRIVE and facemask oxygenation are still controversial, and the main objective of this systematic review is to determine the advantages of THRIVE over facemask oxygenation in intensive care units, respiratory medicine, and perioperative preoxygenation.

Methods

PubMed, Embase, Web of Science, and Cochrane Library have search restrictions. The search library was full of English language articles from the first publication to 15 July 2021. Eligible randomized controlled study designs were included. 245 records were screened, and 5 studies met the inclusion criteria, enrolling a total of 235 patients.

Results

Studying the THRIVE group compared to the facemask group, three studies analyzing intubation time showed that there is no difference in the effect of THRIVE and facemasks (MD -1.22, 95% CI -7.23 to 4.78, and P = 0.69 > 0.05). Three studies analyzing apnea showed that there was no difference between the two groups (SMD 1, 95% CI -0.76 to 2.76, and P = 0.27 > 0.05). Three studies analyzing PaO₂ after preoxygenation showed that THRIVE is more effective than facemasks (MD 72.58, 95% CI 31.25 to 113.90, Z = 3.44, and P < 0.001). Two studies analyzing oxygen saturation SpO₂ after successful intubation showed that there was no difference in the effectiveness (MD 0.09, 95% CI -1.03 to 1.22, and P = 0.87 > 0.05). Two studies analyzing PCO₂ after complete paralysis or intubation preoxygenation showed that there was no difference between the two groups (MD 2.76, 95% CI -1.74 to 7.26, and P = 0.23 > 0.05).

Conclusions

THRIVE does not have a greater advantage over a facemask in improving apnea time, oxygenation time, PCO₂, and SpO₂, but it has an advantage in improving arterial partial pressure of oxygen (PaO₂) after preoxygenation, which can improve PaO₂ well. This trial is registered with the protocol registration number CRD42021268143.

Comparison of the effectiveness of high-flow nasal oxygen vs. standard facemask oxygenation for pre- and apneic oxygenation during anesthesia induction: a systematic review and meta-analysis

BACKGROUND

In recent years, high flow nasal oxygen (HFNO) has been widely used in clinic, especially in perioperative period. Many studies have discussed the role of HFNO in pre- and apneic oxygenation, but their results are controversial. Our study aimed to examine the effectiveness of HFNO in pre- and apneic oxygenation by a meta-analysis of RCTs.

METHODS

EMBASE, PUBMED, and COCHRANE LIBRARY databases were searched from inception to July 2021 for relevant randomized controlled trails (RCTs) on the effectiveness of HFNO versus standard facemask ventilation (FMV) in pre- and apenic oxygenation. Studies involving one of the following six indicators: (1) Arterial oxygen partial pressure (PaO2), (2) End expiratory oxygen concentration (EtO2), (3) Safe apnoea time, (4) Minimum pulse oxygen saturation (SpO2min), (5) Oxygenation (O2) desaturation, (6) End expiratory carbon dioxide (EtCO2) or Arterial carbon dioxide partial pressure(PaCO2) were included. Due to the source of clinical heterogeneity in the observed indicators in this study, we adopt random-effects model for analysis, and express it as the mean difference (MD) or risk ratio (RR) with a confidence interval of 95% (95%CI). We conducted a risk assessment of bias for eligible studies and assessed the overall quality of evidence for each outcome.

RESULTS

Fourteen RCTs and 1012 participants were finally included. We found the PaO2 was higher in HFNO group than FMV group with a MD (95% CI) of 57.38 mmHg (25.65 to 89.10; p = 0.0004) after preoxygenation and the safe apnoea time was significantly longer with a MD (95% CI) of 86.93 s (44.35 to 129.51; p < 0.0001) during anesthesia induction. There were no significant statistical difference in the minimum SpO2, CO2 accumulation, EtO2 and O2 desaturation rate during anesthesia induction between the two groups.

CONCLUSIONS

This systematic review and meta-analysis suggests that HFNO should be considered as an oxygenation tool for patients during anesthesia induction. Compared with FMV, continuous use of HFNO during anesthesia induction can significantly improve oxygenation and prolong safe apnoea time in surgical patients.

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 adult acute hypoxemic respiratory failure in the ED setting: A narrative review

Introduction

High flow nasal cannula (HFNC) is a noninvasive ventilation (NIV) system that has demonstrated promise in the emergency department (ED) setting.

Objective

This narrative review evaluates the utility of HFNC in adult patients with acute hypoxemic respiratory failure in the ED setting.

Discussion

HFNC provides warm (37 °C), humidified (100% relative humidity) oxygen at high flows with a reliable fraction of inspired oxygen (FiO₂). HFNC can improve oxygenation, reduce airway resistance, provide humidified flow that can flush anatomical dead space, and provide a low amount of positive end expiratory pressure. Recent literature has demonstrated efficacy in acute hypoxemic respiratory failure, including pneumonia, acute respiratory distress syndrome (ARDS), coronavirus disease 2019 (COVID-19), interstitial lung disease, immunocompromised states, the peri-intubation state, and palliative care, with reduced need for intubation, length of stay, and mortality in some of these conditions. Individual patient factors play an important role in infection control risks with respect to the use of HFNC in patients with COVID-19. Appropriate personal protective equipment, adherence to hand hygiene, surgical mask placement over the HFNC device, and environmental controls promoting adequate room ventilation are the foundation for protecting healthcare personnel. Frequent reassessment of the patient placed on HFNC is necessary; those with severe end organ dysfunction, thoracoabdominal asynchrony, significantly increased respiratory rate, poor oxygenation despite HFNC, and tachycardia are at increased risk of HFNC failure and need for further intervention.

Conclusions

HFNC demonstrates promise in several conditions requiring respiratory support. Further randomized trials are needed in the ED setting.

The role for high flow nasal cannula as a respiratory support strategy in adults: a clinical practice guideline

Purpose

High flow nasal cannula (HFNC) is a relatively recent respiratory support technique which delivers high flow, heated and humidified controlled concentration of oxygen via the nasal route. Recently, its use has increased for a variety of clinical indications. To guide clinical practice, we developed evidence-based recommendations regarding use of HFNC in various clinical settings.

Methods

We formed a guideline panel composed of clinicians, methodologists and experts in respiratory medicine. Using GRADE, the panel developed recommendations for four actionable questions.

Results

The guideline panel made a strong recommendation for HFNC in hypoxemic respiratory failure compared to conventional oxygen therapy (COT) (moderate certainty), a conditional recommendation for HFNC following extubation (moderate certainty), no recommendation regarding HFNC in the peri-intubation period (moderate certainty), and a conditional recommendation for postoperative HFNC in high risk and/or obese patients following cardiac or thoracic surgery (moderate certainty).

Conclusions

This clinical practice guideline synthesizes current best-evidence into four recommendations for HFNC use in patients with hypoxemic respiratory failure, following extubation, in the peri-intubation period, and postoperatively for bedside clinicians.

Electronic supplementary material

The online version of this article (10.1007/s00134-020-06312-y) contains supplementary material, which is available to authorized users.

Lung volume changes in Apnoeic Oxygenation using Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) compared to mechanical ventilation in adults undergoing laryngeal surgery

BACKGROUND

Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) using high-flow 100% oxygen during apnoea has gained increased use during difficult airway management and laryngeal surgery due to a slower carbon dioxide rise compared to traditional apnoeic oxygenation. We have previously demonstrated high arterial oxygen partial pressures and an increasing arterial-alveolar carbon dioxide difference during THRIVE. Primary aim of this study was to characterise lung volume changes measured with electrical impedance tomography during THRIVE compared to mechanical ventilation.

METHODS

Thirty adult patients undergoing laryngeal surgery under general anaesthesia were randomised to THRIVE or mechanical ventilation. Subjects were monitored with electrical impedance tomography and repeated blood gas measurement perioperatively. The THRIVE group received 100% oxygen at 70 l min^-1 during apnoea. The mechanical ventilation group was intubated and normoventilated with an FiO₂ of 0.4.

RESULTS

Mean age were 48.2 (19.9) and 51.3 (12.3) years, and BMI 26.0 (4.5) and 26.0 (3.9) in the THRIVE and mechanical ventilation group respectively. Mean apnoea time in the THRIVE group was 17.9 (4.8) min. Mean apnoea to end-of-surgery time was 28.1 (12.8) min in the mechanical ventilation group. No difference in delta End Expiratory Lung Impedance was seen between groups over time. In the THRIVE group all but three subjects were well oxygenated during apnoea. THRIVE was discontinued for the three patients who desaturated.

CONCLUSIONS

No difference in lung volume change over time, measured by electrical impedance tomography, was detected when using THRIVE compared to mechanical ventilation during laryngeal surgery.

Moderate Certainty Evidence Suggests the Use of High-Flow Nasal Cannula Does Not Decrease Hypoxia When Compared With Conventional Oxygen Therapy in the Peri-Intubation Period: Results of a Systematic Review and Meta-Analysis

OBJECTIVE

The role of high-flow nasal cannula during and before intubation is unclear despite a number of randomized clinical trials. Our objective was to conduct a systematic review and meta-analysis examining the benefits of high-flow nasal cannula in the peri-intubation period.

DATA SOURCES

We performed a comprehensive search of relevant databases (MEDLINE, EMBASE, and Web of Science).

STUDY SELECTION

We included randomized clinical trials that compared high-flow nasal cannula to other noninvasive oxygen delivery systems in the peri-intubation period.

DATA EXTRACTION

Our primary outcome was severe desaturation (defined as peripheral oxygen saturation reading < 80% during intubation). Secondary outcomes included peri-intubation complications, apneic time, PaO2 before and after intubation, PaCO2 after intubation, ICU length of stay, and short-term mortality.

DATA SYNTHESIS

We included 10 randomized clinical trials (n = 1,017 patients). High-flow nasal cannula had no effect on the occurrence rate of peri-intubation hypoxemia (relative risk, 0.98; 95% CI, 0.68-1.42; 0.3% absolute risk reduction, moderate certainty), serious complications (relative risk, 0.87; 95% CI, 0.71-1.06), apneic time (mean difference, 10.3 s higher with high-flow nasal cannula; 95% CI, 11.0 s lower to 31.7 s higher), PaO2 measured after preoxygenation (mean difference, 3.6 mm Hg higher; 95% CI, 3.5 mm Hg lower to 10.7 mm Hg higher), or PaO2 measured after intubation (mean difference, 27.0 mm Hg higher; 95% CI, 13.2 mm Hg lower to 67.2 mm Hg higher), when compared with conventional oxygen therapy. There was also no effect on postintubation PaCO2, ICU length of stay, or 28-day mortality.

CONCLUSIONS

We found moderate-to-low certainty evidence that the use of high-flow nasal cannula likely has no effect on severe desaturation, serious complications, apneic time, oxygenation, ICU length of stay, or overall survival when used in the peri-intubation period when compared with conventional oxygen therapy.

Nasal high-flow oxygen in pediatric anesthesia and airway management

Nasal High-Flow (NHF) is weight-dependent in children, aimed to match peak inspiratory flow and thereby deliver an accurate FiO₂ with a splinting pressure of 4-6 cm H₂ O. During apnea in children, NHF oxygen can double the expected time to desaturation below 90% in well children but there is no ventilatory exchange; therefore, children do not "THRIVE". Total intravenous anesthesia competency to maintain spontaneous breathing is an important adjunct for successful NHF oxygenation technique during anesthesia. Jaw thrust to maintain a patent upper airway is paramount until surgical instrumentation occurs. There is no evidence to support safe use of NHF oxygen with LASER use due to increased risk of airway fire.

Supraglottic jet oxygenation and ventilation - A novel ventilation technique

Supraglottic jet oxygenation and ventilation (SJOV) is a novel minimally invasive supraglottic technique of jet ventilation which has shown superior results in maintaining oxygenation without any major complications. Theoretically, it could maintain PaO₂ and PaCO₂ within physiological limits for as long as required, the maximum duration reported till now is 45 min. The distinct advantage of SJOV over techniques of nasal oxygenation is its ability to record EtCO₂ during the periods of ventilation. In addition, it also provides reliable airway access by the blind passage of the endotracheal tube into the trachea with a high success rate even in Cormack-Lehane-III (CLIII) grading patients. Potential complications seen with SJOV include nasal bleed and sore throat. No studies have shown to cause severe barotrauma. In this article, we review the evidence regarding oxygenation, ventilation, indications, airway patency and complications of SJOV in comparison to other more commonly used supraglottic oxygenation and ventilation devices.

High-flow nasal oxygenation for anesthetic management

High-flow nasal oxygenation (HFNO) is a promising new technique for anesthesiologists. The use of HFNO during the induction of anesthesia and during upper airway surgeries has been initiated, and its applications have been rapidly growing ever since. The advantages of this technique include its easy set-up, high tolerability, and its abilities to produce positive airway pressure and a high fraction of inspired oxygen and to influence the clearance of carbon dioxide to some extent. HFNO, via a nasal cannula, can provide oxygen both to patients who can breathe spontaneously and to those who are apneic; further, this technique does not interfere with bag-mask ventilation, attempts at laryngoscopy for tracheal intubation, and surgical procedures conducted in the airway. In this review, we describe the techniques associated with HFNO and the advantages and disadvantages of HFNO based on the current state of knowledge.