The Effect of High-Flow Nasal Oxygen on Carbon Dioxide Accumulation in Apneic or Spontaneously Breathing Adults During Airway Surgery: A Randomized-Controlled Trial

Clinical Approach to Central Airway Obstruction in Adult Patients: Perioperative Focus on Causes and Management Including Tracheobronchial Stenting

Central airway obstruction (CAO) is a life-threatening condition associated with poor prognosis. Therapeutic bronchoscopy along with systemic therapies significantly improve survival and quality of life in patients with symptomatic benign and malignant CAO. Endoluminal therapies and tracheobronchial stenting may be used, and a multidisciplinary approach is essential for holistic management of CAO. Perioperative planning and evaluation, as well as attention to intraoperative and postoperative management are key to optimal outcomes. This review provides an overview of the etiology and clinical approach to CAO, perioperative considerations for endoluminal therapies and tracheobronchial stenting, perioperative evaluation and preparation for therapeutic bronchoscopy, and management of operative and postoperative challenges in CAO.

Comparison of high-flow nasal oxygenation and standard low-flow nasal oxygenation during rigid bronchoscopy: a randomized controlled trial

BACKGROUND

The efficacy of high-flow nasal oxygenation (HFNO) in improving oxygenation is influenced by several factors, and its effectiveness is not always guaranteed. Therefore, we aimed to compare the effects of HFNO and standard low-flow nasal oxygenation during rigid bronchoscopy in the apneic patients.

METHODS

All patients were administered general anesthesia with full muscle relaxation and were randomly assigned to receive either HFNO (HFNO group) or standard low-flow oxygenation (Standard group). The study endpoints included the lowest peripheral oxygen saturation (SpO2), hypoxemia-related surgical interruptions (SpO2 ≤ 94%), and changes in arterial oxygen tension (PaO2) and carbon dioxide tension (PaCO2) during the apnea period for rigid bronchoscopy.

RESULTS

A total of 53 patients completed the study. No significant differences were found between the HFNO and the Standard groups in the lowest SpO2 levels (median [Q1, Q3]; 99 [98, 100]% vs. 98 [94, 100]%, P = 0.059) and in the increase rate of PaCO2 (mean ± standard deviation [SD]; 1.6 ± 0.7 mmHg/min vs. 2.0 ± 0.8 mmHg/min, P = 0.064). However, the HFNO group had fewer patients with hypoxemia-related surgical interruptions than the Standard group (1 [3.8%] vs. 8 [29.6%], P = 0.024) and exhibited an attenuated decline rate in PaO2 (median [Q1, Q3]: 4.6 [0.0, 7.9] mmHg/min vs. 10.5 [6.4, 12.9] mmHg/min, P = 0.005).

CONCLUSIONS

While HFNO did not enhance the lowest SpO2 levels in comparison with standard low-flow oxygenation, it did reduce hypoxemia-related surgical interruptions with an attenuated decline in PaO2. Therefore, HFNO has considerable clinical efficacy for rigid bronchoscopy.

Apnoeic oxygenation with high flow nasal oxygen for interventional surgery of the larynx and pharynx

BACKGROUND

Highflow nasal cannula oxygen (HFNO) is known to be used for noninvasive oxygenation in intensive care patients but it has rarely been used in airway management for elective surgery of the upper aerodigestive tract.

OBJECTIVES

HFNO offers opportunities of a tubeless oxygenation system which is easy to handle and not limited only on surgery of the endolarynx.

METHODS

We evaluated this method for oxygenation during brief interventional procedures of the larynx and pharynx in 92 adult patients for safety and intraoperative complications. The need of secondary endotracheal intubation and limiting comorbidities as pulmonal and cardiac diseases were documented.

RESULTS

HFNO showed a good safety profile concerning saturation and hypercapnia. Oxygen desaturation below 90% occurred only in 5 patients, mask ventilation led to quick recovery except in one patient who was secondary intubated. A significant influence of the body mass index on the minimal O2 saturation was shown (p < 0,001) so that a possible limitation of the method exists here. Comorbidities were grouped into the ASA classification. There was a significant difference between ASA I/II and ASA III patients in terms of minimum O2saturation.

CONCLUSION

We conclude that HFNO may hold great promise for changing ventilator technique in general anesthesia, particularly in short elective laryngeal and pharyngeal surgery. Safety and feasibility were proven in this study.

Pre-oxygenation with high-flow oxygen through the nasopharyngeal airway compared to facemask on carbon dioxide clearance in emergency adults: a prospective randomized non-blinded clinical trial

INTRODUCTION

Before tracheal intubation, it is essential to provide sufficient oxygen reserve for emergency patients with full stomachs. Recent studies have demonstrated that high-flow nasal oxygen (HFNO) effectively pre-oxygenates and prolongs apneic oxygenation during tracheal intubation. Despite its effectiveness, the use of HFNO remains controversial due to concerns regarding carbon dioxide clearance. The air leakage and unknown upper airway obstruction during HFNO therapy cause reduced oxygen flow above the vocal cords, possibly weaken the carbon dioxide clearance.

METHODS

Patients requiring emergency surgery who had fasted < 8 h and not drunk < 2 h were randomly assigned to the high-flow group, who received 100% oxygen at 30-60 L/min through nasopharyngeal airway (NPA), or the mask group, who received 100% oxygen at 8 L/min. PaO2 and PaCO2 were measured immediately before pre-oxygenation (T0), anesthesia induction (T1), tracheal intubation (T2), and mechanical ventilation (T3). The gastric antrum's cross-sectional area (CSA) was measured using ultrasound technology at T0, T1, and T3. Details of complications, including hypoxemia, reflux, nasopharyngeal bleeding, postoperative pulmonary infection, postoperative nausea and vomiting (PONV), and postoperative nasopharyngeal pain, were recorded. The primary outcomes were PaCO2 measured at T1, T2, and T3. The secondary outcomes included PaO2 at T1, T2, and T3, CSA at T1 and T3, and complications happened during this trial.

RESULTS

Pre-oxygenation was administered by high-flow oxygen through NPA (n = 58) or facemask (n = 57) to 115 patients. The mean (SD) PaCO2 was 32.3 (6.7) mmHg in the high-flow group and 34.6 (5.2) mmHg in the mask group (P = 0.045) at T1, 45.0 (5.5) mmHg and 49.4 (4.6) mmHg (P < 0.001) at T2, and 47.9 (5.1) mmHg and 52.9 (4.6) mmHg (P < 0.001) at T3, respectively. The median ([IQR] [range]) PaO2 in the high-flow and mask groups was 404.5 (329.1-458.1 [159.8-552.9]) mmHg and 358.9 (274.0-413.3 [129.0-539.1]) mmHg (P = 0.007) at T1, 343.0 (251.6-428.7 [73.9-522.1]) mmHg and 258.3 (162.5-347.5 [56.0-481.0]) mmHg (P < 0.001) at T2, and 333.5 (229.9-411.4 [60.5-492.4]) mmHg and 149.8 (87.0-246.6 [51.2-447.5]) mmHg (P < 0.001) at T3, respectively. The CSA in the high-flow and mask groups was 371.9 (287.4-557.9 [129.0-991.2]) mm2 and 386.8 (292.0-537.3 [88.3-1651.7]) mm2 at T1 (P = 0.920) and 452.6 (343.7-618.4 [161.6-988.1]) mm2 and 385.6 (306.3-562.0 [105.5-922.9]) mm2 at T3 (P = 0.173), respectively. The number (proportion) of complications in the high-flow and mask groups is shown below: hypoxemia: 1 (1.7%) vs. 9 (15.8%, P = 0.019); reflux: 0 (0%) vs. 0 (0%); nasopharyngeal bleeding: 1 (1.7%) vs. 0 (0%, P = 1.000); pulmonary infection: 4 (6.9%) vs. 3 (5.3%, P = 1.000); PONV: 4 (6.9%) vs. 4 (7.0%, P = 1.000), and nasopharyngeal pain: 0 (0%) vs. 0 (0%).

CONCLUSIONS

Compared to facemasks, pre-oxygenation with high-flow oxygen through NPA offers improved carbon dioxide clearance and enhanced oxygenation prior to tracheal intubation in patients undergoing emergency surgery, while the risk of gastric inflation had not been ruled out.

TRIAL REGISTRATION

This trial was registered prospectively at the Chinese Clinical Research Registry on 26/4/2022 (Registration number: ChiCTR2200059192).

Successful Application of Transnasal Humidified Rapid-Insufflation Ventilatory Exchange in a Case of Subglottic Stenosis

We widely employ microlaryngeal surgery to treat diverse oropharyngeal and laryngeal conditions, but it presents challenges to shared airway management. This case report addresses the limitations of conventional techniques, such as tracheal intubation and jet ventilation, and explores the emerging interest in transnasal humidified rapid insufflation ventilatory exchange (THRIVE). While THRIVE offers advantages such as enhanced visualization and reduced airway trauma, its application is limited by the duration of apnea, with the literature referring to a maximum of 30 minutes of apnea. We present the successful application of THRIVE as the primary airway management technique in a patient undergoing a 55-minute dilation procedure for subglottic stenosis. Successful oxygenation was achieved, creating a tubeless field and improving visibility. The patient maintained oxygen saturation above 98%, demonstrating the effectiveness of THRIVE in managing prolonged apnea. Remarkably, intentional ventilation via a face mask at specific moments allowed extended apneic oxygenation without harmful carbon dioxide levels. This report complies with the growing evidence supporting the efficacy of THRIVE in providing extended apnea for tubeless surgery. The success demonstrated in our case highlights the feasibility and effectiveness of THRIVE in situations demanding prolonged apnea and complex airway management.

Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR), Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) Guideline for difficult airway management. Part I

The Airway Management section of the Spanish Society of Anesthesiology, Resuscitation, and Pain Therapy (SEDAR), the Spanish Society of Emergency Medicine (SEMES), and the Spanish Society of Otorhinolaryngology and Head and Neck Surgery (SEORL-CCC) present the Guide for the comprehensive management of difficult airway in adult patients. Its principles are focused on the human factors, cognitive processes for decision-making in critical situations, and optimization in the progression of strategies application to preserve adequate alveolar oxygenation in order to enhance safety and the quality of care. The document provides evidence-based recommendations, theoretical-educational tools, and implementation tools, mainly cognitive aids, applicable to airway management in the fields of anesthesiology, critical care, emergencies, and prehospital medicine. For this purpose, an extensive literature search was conducted following PRISMA-R guidelines and was analyzed using the GRADE methodology. Recommendations were formulated according to the GRADE methodology. Recommendations for sections with low-quality evidence were based on expert opinion through consensus reached via a Delphi questionnaire.

Optimizing nonintubated laryngeal microsurgery: The effectiveness and safety of superior laryngeal nerve block with high-flow nasal oxygen-A prospective cohort study

BACKGROUND

Laryngeal microsurgery (LMS) typically requires intubated general anesthesia (ITGA). Although nonintubated general anesthesia (NIGA) with high-flow nasal oxygen (HFNO) can be applied with LMS, a muscle relaxant is required, which can cause apnea and hypercapnia. This study evaluated the effectiveness of a superior laryngeal nerve block (SLNB) in improving safety during LMS.

METHODS

This prospective cohort study enrolled a cumulative total of 61 adult patients received LMS under intravenous general anesthesia and allocated to three groups: ITGA group (n = 18), which patients performed intubation; neuromuscular blocking (NMB) group (n = 21), which patients administrated muscle relaxant without intubation and superior laryngeal nerve block (NB) group (n = 22), which patients performed SLNB without intubation or muscle relaxant.

RESULTS

The average (SD) values of PaCO 2 after surgery in ITGA, NMB, and NB group were 50.8 (7.5), 97.5 (24.9), and 54.8 (8.8) mmHg, respectively. The mean postoperative pH values were 7.33 (0.04), 7.14 (0.07), and 7.33 (0.04), respectively. The results were all p < 0.001, and the average pH value of the NMB group was lower than that of the ITGA and NB groups. During the LMS, the mean heart rate (HR) (93.9 [18.1] bpm) and noninvasive blood pressure systolic (NBPs) (143.5 [28.2] mmHg) in the NMB group were higher than those in the ITGA group (HR = 77.4 [13.5] bpm and NBPs = 132.7 [20.8] mmHg) and NB group (HR = 82.3 [17.4] bpm and NBPs = 120.9 [25.0] mmHg). The results of p value by HR and NBPs are p < 0.001. The PaCO 2 and pH values are similar between ITGA group and NB group.

CONCLUSION

Our approach of using HFNO with SLNB was successful for performing nonintubated LMS, enabling the patients to maintain spontaneous breathing and effectively eliminate CO 2 . This approach reduces the risks of hypercapnia and acidosis even when the duration of LMS exceeds 30 minutes.

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

Background

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

Methods

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

Results

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

Conclusion

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

Efficacy of high-flow nasal oxygen during drug-induced sleep endoscopy in patients with obstructive sleep apnea

PURPOSE

High-flow nasal oxygenation (HFNO) can provide a low level of continuous positive airway pressure and alveolar recruitment. We aimed to compare the efficacy of pre-oxygenation with HFNO and low-flow nasal oxygenation (LFNO) during drug-induced sleep endoscopy (DISE).

METHODS

In the LFNO group, preoxygenation was performed for 10 min at 3 L·min-1. In the HFNO group, preoxygenation was performed for 10 min at 30 L·min-1 at a fraction of inspired oxygen of 100% using the Optiflow device. From the start of sedative administration to the end of DISE, vital signs were monitored continuously. The primary outcome was the lowest oxygen saturation (SpO2) during DISE.

RESULTS

Of 24 patients enrolled, 12 were randomly assigned to the LFNO and 12 to the HFNO groups. The prevalence of hypoxia events was 75% in the LFNO group and 58% in the HFNO group. The difference in lowest oxygen saturation between the two groups was not significant between the two groups (P=0.665). The lowest SpO2 during all procedures was comparable between the two groups (86.8 ± 6.5% in the LFNO group and 87.2 ± 8.0% in the HFNO group; P=0.912).

CONCLUSIONS

The findings suggest that HFNO may not be superior to LFNO as a preoxygenation tool to prevent hypoxia during DISE.

Effect of trans-nasal humidified rapid insufflation ventilatory exchange on reflux and microaspiration in patients undergoing laparoscopic cholecystectomy during induction of general anesthesia: a randomized controlled trial

Background

Reflux aspiration is a rare but serious complication during induction of anesthesia. The primary aim of this study is to compare the incidence of reflux and microaspiration in patients undergoing laparoscopic cholecystectomy during induction of general anesthesia using either a facemask or trans-nasal humidified rapid insufflation ventilatory exchange.

Methods

We conducted a single-center, randomized, controlled trial. Thirty patients were allocated to either a facemask or a trans-nasal humidified rapid insufflation ventilatory exchange (THRIVE) group. Pre-oxygenation for 5 min with a facemask or THRIVE, positive pressure ventilation for 2 min or THRIVE for 2 min after anesthesia induction was followed. Before endotracheal intubation, the secretion above and below the glottis was collected to measure pepsin content and analyze blood gas. The ELISA assay for supra- and subglottic human pepsin content was used to detect the presence of reflux and microaspiration. The primary outcome was the incidence of reflux and microaspiration. Secondary outcomes were apnea time, PaO2 before tracheal intubation, and the end-expiratory carbon dioxide partial pressure.

Results

Patients in the THRIVE group had a significantly longer apnea time (379.55 ± 94.12 s) compared to patients in the facemask group (172.96 ± 58.87 s; p < 0.001). There were no differences observed in PaO2 between the groups. A significant difference in gastric insufflation, reflux, and microaspiration was observed between the groups. Gastric insufflation was 6.9% in the THRIVE group vs. 28.57% kPa in the facemask group (p = 0.041); reflux was 10.34% in the THRIVE group vs. 32.14% kPa in the facemask group (p = 0.044); and microaspiration was 0% in the THRIVE group vs. 17.86% kPa in the facemask group (p = 0.023).

Conclusion

The application of THRIVE during induction of general anesthesia reduced the incidence of reflux and microaspiration while ensuring oxygenation and prolonged apnea time in laparoscopic cholecystectomy patients. THRIVE may be an optimal way to administer oxygen during the induction of general anesthesia in laparoscopic cholecystectomy patients.

Clinical trial registration

Chinese Clinical Trial Registry, No: ChiCTR2100054086, https://www.chictr.org.cn/indexEN.html.

Examining readmissions following outpatient microlaryngeal surgery

Objective

The objective of this study was to examine readmissions following microlaryngeal surgery. It was hypothesized that airway surgical procedures would have higher rates of readmission.

Design

Retrospective review.

Methods

Outpatient microlaryngeal surgeries from May 1, 2018 to November 27, 2022 were reviewed. Readmissions related to the original surgery within a 30-day postoperative period were examined. Patient demographics, body mass index, American Society of Anesthesiologist class, comorbidities, type of surgery, ventilation techniques, and operative times were examined and compared.

Results

Out of 480 procedures analyzed, 19 (4.0%) resulted in a readmission, 9 (1.9%) of which were for glottic stenosis management. Undergoing an airway procedure was significantly associated with a readmission (p = .002) and increased the odds of readmission by 5.99 (95% confidence interval [CI]: 2.22-16.16, p < .001). Current/former smoking status increased the odds of readmission by 4.50 (95% CI: 1.33-15.19, p = .016). Each additional minute of operating time increased the odds of readmission by 1.03 (95% CI: 1.00-1.05, p = .04).

Conclusion

Readmissions from microlaryngeal surgery are seldom reported but nonetheless occur. Identifying factors that may place a procedure at risk for readmission can help improve surgical quality of care.

Level of Evidence

4.

Effectiveness of Face mask only oxygenation and apnoeic oxygenation in addition to face mask in sustaining PaO2 during rapid sequence induction - A randomized control trial

Background and Aims

Apnoeic oxygenation, although useful during elective intubations, has not shown consistent beneficial results during emergency intubations in critically ill patients. We aimed to study the effectiveness of adding apnoeic oxygenation to our routine practice of using facemask alone, in emergency laparotomy patients needing rapid sequence induction (RSI), for sustaining partial pressure of oxygen (PaO2).

Material and Methods

Seventy-two patients undergoing RSI for emergency laparotomy were randomly allocated to either receive pre-oxygenation with 5 L/min of oxygen (O2) with a facemask (Group-FM) or apnoeic oxygenation with 10 L/min of O2 through a nasal catheter in addition to pre-oxygenation (Group-NC). Apnoea (90 s) was allowed from the removal of the facemask before the resumption of ventilation. Arterial blood gas analysis was done at the baseline, following pre-oxygenation and after 90 s of apnoea to study the PaO2 and partial pressure of carbon dioxide (PaCO2). The circuit O2 concentrations (fraction of inspired [FiO2] and end-tidal [EtO2]) were also noted to ensure a steady state of O2 uptake was reached.

Results

The circuit O2 concentrations were 90 ± 4% in group FM and 93 ± 5% in Group-NC. The FiO2-EtO2 difference was 4% in both groups. During the 90 s apnoea following pre-oxygenation, there was a fall in the PaO2 by 38% in Group-FM and 12% in Group-NC (P = 0.000). Increase in PaCO2 was similar in both groups (Group-FM: 44 [range: 32-55] mmHg; Group-NC: 42 [range: 33-54] mmHg, P = 0.809).

Conclusion

Apnoeic insufflation of O2 using a nasopharyngeal catheter along with facemask oxygenation is more effective in sustaining PaO2 for 90 s during RSI than facemask-only oxygenation in patients undergoing emergency laparotomy.

The effect of intraoperative transnasal humidified rapid-insufflation ventilatory exchange on emergence from general anesthesia in patients undergoing microlaryngeal surgery: a randomized controlled trial

BACKGROUND

Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) has received extensive attention for its utility in tubeless anesthesia. Still, the effects of its carbon dioxide accumulation on emergence from anesthesia have not been reported. This randomized controlled trial aimed at exploring the impact of THRIVE combined with laryngeal mask (LM) on the quality of emergence in patients undergoing microlaryngeal surgery.

METHODS

After research ethics board approval, 40 eligible patients receiving elective microlaryngeal vocal cord polypectomy were randomly allocated 1:1 to two groups, THRIVE + LM group: intraoperative apneic oxygenation using THRIVE followed by mechanical ventilation through a laryngeal mask in the post-anesthesia care unit (PACU), or MV + ETT group: mechanically ventilated through an endotracheal tube for both intraoperative and post-anesthesia periods. The primary outcome was duration of PACU stay. Other parameters reflecting quality of emergence and carbon dioxide accumulation were also recorded.

RESULTS

Duration of PACU stay (22.4 ± 6.4 vs. 28.9 ± 8.8 min, p = 0.011) was shorter in the THRIVE + LM group. The incidence of cough (2/20, 10% vs. 19/20, 95%, P < 0.001) was significantly lower in the THRIVE + LM group. Peripheral arterial oxygen saturation and mean arterial pressure during intraoperative and PACU stay, Quality of Recovery Item 40 total score at one day after surgery and Voice Handicap Index-10 score at seven days after surgery were of no difference between two groups.

CONCLUSIONS

The THRIVE + LM strategy could accelerate emergence from anesthesia and reduce the incidence of cough without compromising oxygenation. However, these benefits did not convert to the QoR-40 and VHI-10 scores improvement.

TRIAL REGISTRATION

ChiCTR2000038652.

High-flow Nasal Cannula versus Conventional Ventilation in Laryngeal Surgery: A Systematic Review and Meta-analysis

High-flow nasal cannula (HFNC) is an emerging option for maintaining oxygenation in patients undergoing laryngeal surgery, as an alternative to traditional tracheal ventilation and jet ventilation (JV). However, the data on its safety and efficacy is sparse. This study aims to aggregate the current data and compares the use of HFNC with tracheal intubation and jet ventilation in adult patients undergoing laryngeal surgery. We searched PubMed, MEDLINE (Medical Literature Analysis and Retrieval System Online, or MEDLARS Online), Embase (Excerpta Medica Database), Google Scholar, Cochrane Library, and Web of Science. Both observational studies and prospective comparative studies were included. Risk of bias was appraised with the Cochrane Collaboration Risk of Bias in Non-Randomized Studies - of Interventions (ROBINS-I) or RoB2 tools and the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for case series. Data were extracted and tabulated as a systematic review. Summary statistics were performed. Meta-analyses and trial sequential analyses of the comparative studies were performed. Forty-three studies (14 HFNC, 22 JV, and seven comparative studies) with 8064 patients were included. In the meta-analysis of comparative studies, the duration of surgery was significantly reduced in the THRIVE (Transnasal Humidified Rapid-Insufflation Ventilatory Exchange) group, but the number of desaturations, need for rescue intervention, and peak end-tidal CO₂ were significantly increased compared to the conventional ventilation group. The evidence was of moderate certainty and there was no evidence of publication bias. In conclusion, HFNC may be as effective as tracheal intubation in oxygenation during laryngeal surgery in selected adult patients and reduces the duration of surgery but conventional ventilation with tracheal intubation may be safer. The safety of JV was comparable to HFNC.

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.

Tube or tubeless: an anesthetic strategy for upper airway surgery

Since the patient's airway is shared between an anesthesiologist and a surgeon, airway management during upper airway surgery can be challenging. Beyond the conventional method of general anesthesia, high-flow nasal oxygenation (HFNO) has recently been used as a key technique for tubeless anesthesia. HFNO provides humidified, heated oxygen up to 70 L/min, which promises improved oxygenation and ventilation, allowing for prolonged apneic oxygenation. In previous physiological and clinical studies, HFNO has been demonstrated that tubeless anesthesia safely provide an uninterrupted surgical field during laryngeal surgeries. Although tubeless anesthesia remains uncommon, it can be a good alternative to conventional anesthesia if an anesthesiologist and a surgeon select appropriate patients together with sufficient experience. A safe strategy for tubeless anesthesia, along with appropriate backup plans, including endotracheal intubation and high-frequency jet ventilation, should be considered for upper airway surgery.

High or mid-flow oxygen therapy for primary headache disorders: A randomized controlled study

BACKGROUND

Headache is one of the most common causes of emergency department (ED) visits. High-flow oxygen therapy is becoming more attractive as a treatment option because it is safe, effective, and cheap. We aimed to compare the effectiveness of high and medium-flow oxygen therapies with placebo for treating primary headache disorders among middle-aged patients.

METHODS

This prospective, double-blind, placebo-controlled, crossover designed, randomized study was conducted at a regional tertiary hospital's ED. Patients who were treated for primary headache disorder in the ED were evaluated at the time of diagnosis and subsequently included in the study upon their next ED visit. Four different treatment methods were administered; 1) high-flow oxygen (15 L/min oxygen), 2) medium-flow oxygen (8 L/min oxygen), 3) high-flow room air as placebo (15 L/min room air), 4) medium-flow room air as placebo (8 L/min room air). All four treatment methods were administered to all patients included in the study, at four separate ED visits. Patients' data, including demographics, medical history, additional complaints, Visual Analogue Scale (VAS) score, and physical examination findings were recorded by the treating physician.

RESULTS

One hundred and four patients with a mean age of 35.14 ± 9.1 years, were included in the study. Patients who received oxygen therapy had a significantly lower VAS score at all control points (15, 30, and 60 min) when compared with placebo (p < 0.001). This difference in scores reached its maximum at 30 min. There was not a significant statistical difference between the high-flow or mid-flow therapies (p > 0.05). It was determined that patients who received placebo therapy were more likely to revisit ED (p < 0.05). There was not a significant statistical difference between the high-flow or mid-flow therapy groups in terms of revisit (p > 0.05) and the 30th-minute analgesia requirement (p > 0.05). Pain duration was significantly less in patients who received oxygen therapy (p < 0.05). Patients who received high-flow oxygen therapy spent less time in the ED (p < 0.001).

CONCLUSION

Oxygen therapy could be a beneficial treatment option for middle-aged patients with primary headache disorders. Based on the results obtained from high and mid-flow oxygen therapies, it may be more appropriate to begin treatment with mid-flow oxygen.

Efficacy of high-flow nasal oxygenation compared with laryngeal mask airway in children undergoing ambulatory oral surgery under deep sedation: A randomized controlled non-inferiority trial

BACKGROUND

High-flow nasal oxygenation (HFNO) has been suggested as an alternative oxygenation method during procedural sedation. This randomized, non-inferiority trial evaluated the safety and efficacy of HFNO compared with laryngeal mask airway (LMA) in pediatric ambulatory oral surgery under deep sedation.

METHODS

In total, 120 children aged 2-7 years (weight: 10-30 kg) were equally assigned into two groups, namely, HFNO with propofol total intravenous anesthesia infusion (HFNO-IV) or LMA with propofol total intravenous anesthesia infusion (LMA-IV). The primary objective was to monitor carbon dioxide (CO2) accumulation during perioperative surgery. Secondary objectives included monitoring transcutaneous oxygen saturation, grade exposure to the surgical field, perioperative adverse events, or other events. The predefined non-inferiority margin was 7 mmHg. During the COVID-19 pandemic, a novel WeChat applet was implemented to gather follow-up data after discharge.

RESULTS

Non-inferiority could be declared for HFNO relative to LMA (mean difference in transcutaneous CO2 (TcCO2) = -1.4 mmHg, 95% CI: -2.9, 0.1 mmHg; P > 0.05). The pre-surgical TcCO2 of the HFNO-IV group (45.4 ± 4.5 mmHg) was similar to that of the LMA-IV group (44.0 ± 3.5 mmHg), within the clinically acceptable normal range. All the children maintained SpO2 levels of >97%. The surgical field exposure score of the HFNO group was significantly better than that of the LMA group. There was no significant difference between the two groups regarding risk or adverse events.

CONCLUSION

HFNO was not inferior to LMA for maintaining oxygenation and ventilation in patients undergoing pediatric ambulatory oral surgery under deep sedation under strict isolation from the oral cavity to the upper airway.

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.

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.

The effect of transnasal humidified rapid-insufflation ventilator exchange (THRIVE) versus nasal prongs on safe apnoea time in paralysed obese patients: a randomised controlled trial

BACKGROUND

Evidence is lacking regarding the efficacy of Optiflow transnasal humidified rapid-insufflation ventilator exchange (THRIVE™) in obese patients. We compared the impact of this technique at 70 L min^-1 with 4 L min^-1 oxygen via nasal prongs on safe apnoea times of paralysed obese patients.

METHODS

We randomised adults with a BMI >35 kg m^-2 undergoing elective bariatric surgery. While apnoeic and paralysed, Group T received 70 L min^-1 oxygen via Optiflow THRIVE™. Group N received nasal prong oxygen at 4 L min^-1. The primary outcome was time to SpO₂ ≤95% while apnoeic, with a 360 s cut-off. This was analysed by applying a time-to-event analysis.

RESULTS

Forty-two patients were included. The median (inter-quartile range) BMI was 44.8 kg m^-2 (40.0-50.0) in Group T and 42.0 kg m^-2 (39.3-45.1) in Group N. Median (inter-quartile range) time to SpO₂ ≤95% in Group T was 356 (165 to ≥360) s and in Group N, 210 (160-270) s. Using a survival analysis framework, median time-to-event in Group T was 356 s (95% confidence interval 165 s-upper limit not defined) and 210 s (95% confidence interval 160-242 s) (P=0.049) in Group N.

CONCLUSIONS

Compared with oxygen delivered via nasal prongs at 4 L min^-1, oxygen delivery via Optiflow THRIVE™ at a flow rate of 70 L min^-1 can prolong safe apnoea time, however, the results are statistically inconclusive. Optiflow THRIVE™ did decrease the rate of reduction in Pa_o2 during apnoea.

CLINICAL TRIAL REGISTRATION

ANZCTR 12618000445279.

Efficacy of high-flow nasal oxygenation compared with tracheal intubation for oxygenation during laryngeal microsurgery: a randomised non-inferiority study

BACKGROUND

Oxygenation via a high-flow nasal cannula (HFNC) can be an alternative to tracheal intubation during short apnoeic procedures. This randomised, non-inferiority study assessed the efficacy of HFNC compared with tracheal intubation in laryngeal microsurgery.

METHODS

Patients (≥20 yr old) undergoing laryngeal microsurgery under general anaesthesia and neuromuscular blockade were randomised to either the HFNC or tracheal intubation groups. The primary endpoint was lowest pulse oxygen saturation (SpO₂) during the first 30 min of surgery. Secondary endpoints included incidence of desaturation (SpO₂ <95%), hypercarbia (transcutaneous carbon dioxide [CO₂] ≥8.7 kPa), and rescue intervention.

RESULTS

Amongst 130 patients randomised, 118 were included in the analysis. The lowest SpO₂ was 100 (98-100)% in the HFNC group (n=56) and 100 (100-100)% in the tracheal intubation group (n=62), with a mean difference of -1.4% (95% confidence interval: -2.4% and -0.3%), failing to confirm non-inferiority with a non-inferiority margin of 2%. The peak transcutaneous CO₂ and end-tidal CO₂ at the end of surgery were higher in the HFNC group compared with the tracheal intubation group. Incidences of desaturation, hypercarbia, and rescue intervention were more frequent in patients receiving HFNC compared with tracheal intubation.

CONCLUSIONS

HFNC oxygenation was not non-inferior to tracheal intubation for maintaining oxygen saturation during laryngeal microsurgery. Considering more frequent desaturation, hypercarbia, and requirement for rescue intervention compared with tracheal intubation, HFNC should be used with cautious monitoring even for short duration airway surgery.

CLINICAL TRIAL REGISTRATION

NCT03629353.

To Tube, or Not to Tube: Comparing Ventilation Techniques in Microlaryngeal Surgery

OBJECTIVES/HYPOTHESIS

The objective of this study was to compare ventilation techniques utilized in microlaryngeal surgery.

STUDY DESIGN

Retrospective cohort study.

METHODS

Two-hundred surgeries performed from May 1, 2018 to March 1, 2020 and stratified as intubated, intermittently intubated (AAIV) or apneic. Patient demographics, comorbidities, anesthetic agents, intraoperative parameters/events, and complications were studied and compared across the three groups using inferential analyses.

RESULTS

Median body mass index in the AAIV group was significantly higher (33 vs. 29; P = .0117). Median oxygen nadirs were lower in AAIV cases (81% vs. 91-92%) while CO₂ peak measurements were lower (33 mmHg vs. 48 mmHg) in the fully apneic cohort which were significantly shorter cases (P < .0001). CO₂ peak measurements were comparable between AAIV and intubated cohorts (median 48.5 mmHg vs. 48.0 mmHg). Median apnea times were significantly prolonged by 2-5.5 minutes using nasal cannula and THRIVE/Optiflow in fully apneic cases when compared to no supplementary oxygenation (P = .0013). Systolic blood pressures following insertion of laryngoscope were higher (159.5 vs. 145 mmHg) and postoperative diastolic pressures were lower (68.5 vs. 76.5 mmHg) in fully apneic cases than intubated cases. No differences existed between frequencies of complications.

CONCLUSIONS

This study compares intubated, intermittently apneic, and fully apneic surgeries. No statistically significant differences were noted in comorbid conditions. While intraoperative hemodynamic fluctuations were more pronounced in the fully apneic cohort, and oxygenation distributions were lower in the AAIV cohort, no significant differences existed between events and complications. Apneic techniques are as safe and effective as traditional intubation.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Tracheal Dilatation of an Idiopathic Subglottic Stenosis in a Near-Term Parturient at 36 Weeks of Gestation Using SponTaneous Respiration Using Intravenous Anesthesia and Hi-Flow Nasal Oxygen: A Case Report

Hi-flow nasal oxygen (HFNO) has revolutionized tubeless field anesthesia for airway surgery without the complications of jet ventilation. However, its use in third trimester parturients undergoing open airway surgery has been limited to an apneic technique (Transnasal Humidified Rapid-Insufflation Ventilatory Exchange [THRIVE]) in current publications. We used SponTaneous Respiration using IntraVEnous anesthesia and Hi-flow nasal oxygen (STRIVE Hi) in the management of tracheal dilatation in a near-term parturient at 36 weeks of gestation. Transferring this established protocol for spontaneous ventilation in the obstructed airway onto near-term parturients may mitigate the risks of apnea with hypercapnia, subsequent acidosis, and potential fetal harm.