A physiological study to determine the mechanism of carbon dioxide clearance during apnoea when using transnasal humidified rapid insufflation ventilatory exchange (THRIVE)

The effect of high-flow nasal oxygen flow rate on gas exchange in apnoeic patients: a randomised controlled trial

High-flow nasal oxygen can be administered at induction of anaesthesia for the purposes of pre-oxygenation and apnoeic oxygenation. This intervention is claimed to enhance carbon dioxide elimination during apnoea, but the extent to which this occurs remains poorly quantified. The optimal nasal oxygen flow rate for gas exchange is also unknown. In this study, 114 patients received pre-oxygenation with high-flow nasal oxygen at 50 l.min-1. At the onset of apnoea, patients were allocated randomly to receive one of three nasal oxygen flow rates: 0 l.min-1; 70 l.min-1; or 120 l.min-1. After 4 minutes of apnoea, all oxygen delivery was ceased, tracheal intubation was performed, and oxygen delivery was recommenced when SpO2 was 92%. Mean (SD) PaCO2 rise during the first minute of apnoea was 1.39 (0.39) kPa, 1.41 (0.29) kPa, and 1.26 (0.38) kPa in the 0 l.min-1, 70 l.min-1 and 120 l.min-1 groups, respectively; p = 0.16. During the second, third and fourth minutes of apnoea, mean (SD) rates of rise in PaCO2 were 0.34 (0.08) kPa.min-1, 0.36 (0.06) kPa.min-1 and 0.37 (0.07) kPa.min-1 in the 0 l.min-1, 70 l.min-1 and 120 l.min-1 groups, respectively; p = 0.17. After 4 minutes of apnoea, median (IQR [range]) arterial oxygen partial pressures in the 0 l.min-1, 70 l.min-1 and 120 l.min-1 groups were 24.5 (18.6-31.4 [12.3-48.3]) kPa; 36.6 (28.1-43.8 [9.8-56.9]) kPa; and 37.6 (26.5-45.4 [11.0-56.6]) kPa, respectively; p < 0.001. Median (IQR [range]) times to desaturate to 92% after the onset of apnoea in the 0 l.min-1, 70 l.min-1 and 120 l.min-1 groups, were 412 (347-509 [190-796]) s; 533 (467-641 [192-958]) s; and 531 (462-681 [326-1007]) s, respectively; p < 0.001. In conclusion, the rate of carbon dioxide accumulation in arterial blood did not differ significantly between apnoeic patients who received high-flow nasal oxygen and those who did not.

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.

High-Flow Nasal Oxygen versus Conventional Nasal Cannula in Preventing Hypoxemia in Elderly Patients Undergoing Gastroscopy with Sedation: A Randomized Controlled Trial

Background: We aimed to compare the prevention of hypoxemia using High-flow nasal oxygen (HFNO) or regular nasal tubing (CNC) in elderly patients undergoing gastroscopy with sedation. Methods: This study was a prospective, randomized, controlled trial conducted at a single center. We included elective patients aged 65 and above who were undergoing gastroscopy with sedation. In the intervention group (HFNO), we set the oxygen flow rate to 60 liters per minute with an oxygen fraction (FiO2) of 0.6, while in the control group (CNC), it was 6 liters per minute. The primary outcome was the occurrence of hypoxemia (defined as Spo2 < 90%). Results: A total of 125 participants were enrolled (HFNO group: n = 63; CNC group: n = 62). The occurrence of hypoxemia was found to be significantly lower in the HFNO group compared to the CNC group (3.2% vs. 22.6%, p = 0.001). Additionally, a significantly shorter duration of low oxygen levels was observed in the HFNO group [0.0 seconds (0.0-13.0)] compared to the CNC group [0.0 seconds (0.0-124.0), p<0.001]. Moreover, a higher minimum Spo2 value was achieved in the HFNO group [99.0% (98.0-100.0) vs. 96.5% (91.0-99.0), p < 0.001], and a shorter recovery time was recorded [0.5 minutes (0.0-0.5) vs. 0.5 minutes (0.0-1.0), p = 0.016] in comparison to the CNC group. There were no differences in terms of comfort level [0 (0-4) vs. 0 (0-5), p = 0.268] between the two groups. Conclusions: The HFNO system was determined to be a safe and highly effective method for oxygen delivery, leading to a reduction in the occurrence of hypoxemia in elderly patients undergoing gastroscopy with sedation. It is recommended that HFNO be considered as the standard approach for management in this population.

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.

Transnasal Humidified Rapid Insufflation Ventilatory Exchange in Endoscopic Esophageal Surgery

OBJECTIVES

Transnasal humidified rapid insufflation ventilatory exchange (THRIVE) describes apneic oxygenation using humidified high flow nasal-cannula oxygen. Although it has been described as a sole mode of oxygenation in endoscopic laryngotracheal surgery, its use in endoscopic esophageal surgery under general anesthesia with neuromuscular paralysis has not previously been described. The objective of this study is to assess the safety and efficacy of THRIVE in esophagology.

METHODS

We conducted a retrospective review of adult patients undergoing esophageal procedures under general anesthesia who were oxygenated using THRIVE at two academic institutions. Demographic, clinical, and anesthesiologic data were collected and analyzed.

RESULTS

14 cases performed from March 2021 to March 2022 met inclusion criteria. 13/14 (92.9%) of patients were able to maintain oxygenation throughout the entirety of their procedure. The mean apneic time was 17.9 minutes with a maximum of 32 minutes. One patient required "rescue" intubation due to failure to maintain oxygenation. Excluding the sole THRIVE failure, the median SpO2 at the conclusion of surgery was 99% (range 94-100%). A linear regression model yielded an increase in EtCO2 of 0.95 mmHg/min or 0.127 kPa/min. SpO2 was negatively associated with both tobacco pack-year smoking history (R2 = 0.343, P = .014) and BMI (R2 = 0.238, P = .038).

CONCLUSION

THRIVE is a feasible, safe, and efficacious means of apneic oxygenation for patients undergoing esophageal endoscopic surgery under general anesthesia with neuromuscular paralysis, which may be particularly beneficial in patients with airway stenosis, as post-intubation changes can have severe clinical implications for this patient population. Obese patients and tobacco smokers may be at increased risk of oxygen desaturation when using THRIVE.

Rapid sequence induction of anesthesia: works in progress and steps forward with focus to oxygenation and monitoring techniques

The description of the main scientifically consolidated innovations in recent years on Rapid Sequence Induction have been the subject of this narrative review. Data sources were PubMed, EMBASE, Web of Science, the Cochrane Central Register of Controlled Trials, and ClinicaTrials.gov, searched up to March 21st, 2023; rapid sequence induction and anesthesia were used as key word for the research. In recent years at least three significant innovations which have improved the procedure: firstly the possibility of using drugs which rapidly reverse the action of the myorelaxants and which have made it possible to give up the use of succinylcholine, replaced by rocuronium; secondly, the possibility of using much more effective pre-oxygenation methods than in the past, also through apneic oxygenation techniques which allow longer apnea time, and finally new monitoring systems much more effective than pulse oximetry in identifying and predicting periprocedural hypoxemia and indicating the need for ventilation in patients at risk of hypoxemia and preventing it. The description of three main scientifically consolidated innovations in recent years, in pharmacology, oxygen method of administration and monitoring, have been the subject of this narrative review.

Optimal flow of high-flow nasal cannula oxygenation to prevent desaturation during sedation for bronchoscopy: a randomized controlled study

BACKGROUND

Although high-flow nasal cannula (HFNC) oxygenation is currently recommended to prevent desaturation during sedation for bronchoscopy, there is no consensus on an optimal flow rate.

OBJECTIVE

To determine the optimal oxygen flow rate for HFNC to effectively prevent desaturation during sedation for bronchoscopy.

DESIGN

Prospective, randomized, and controlled study.

METHODS

Patients (n = 240) scheduled for bronchoscopy were randomized to receive HFNC with propofol sedation (fraction of inspired oxygen, 100%) at one of six flow rates of 10, 20, 30, 40, 50, and 60 L/min, designated as groups 1-6, respectively.

RESULTS

The incidence of desaturation significantly decreased by increasing the oxygen flow rate (42.5%, 17.5%, 15%, 10%, 2.5%, and 0% for groups 1-6, respectively, p < 0.0001). The optimal oxygen flow rate for HFNC determined by probit regression to effectively prevent desaturation in 95% of patients was 43.20 (95% confidence interval, 36.43-55.96) L/min. The requirement for airway intervention was significantly decreased by increasing the oxygen flow rate.

CONCLUSION

An HFNC flow rate of 50-60 L/min is recommended to prevent desaturation during sedation for bronchoscopy.

REGISTRATION

NCT05298319 at ClinicalTrials.gov.

Personalized Noninvasive Respiratory Support in the Perioperative Setting: State of the Art and Future Perspectives

Background: Noninvasive respiratory support (NRS), including high-flow nasal oxygen therapy (HFNOT), noninvasive ventilation (NIV) and continuous positive airway pressure (CPAP), are routinely used in the perioperative period. Objectives: This narrative review provides an overview on the perioperative use of NRS. Preoperative, intraoperative, and postoperative respiratory support is discussed, along with potential future areas of research. Results: During induction of anesthesia, in selected patients at high risk of difficult intubation, NIV is associated with improved gas exchange and reduced risk of postoperative respiratory complications. HFNOT demonstrated an improvement in oxygenation. Evidence on the intraoperative use of NRS is limited. Compared with conventional oxygenation, HFNOT is associated with a reduced risk of hypoxemia during procedural sedation, and recent data indicate a possible role for HFNOT for intraoperative apneic oxygenation in specific surgical contexts. After extubation, "preemptive" NIV and HFNOT in unselected cohorts do not affect clinical outcome. Postoperative "curative" NIV in high-risk patients and among those exhibiting signs of respiratory failure can reduce reintubation rate, especially after abdominal surgery. Data on postoperative "curative" HFNOT are limited. Conclusions: There is increasing evidence on the perioperative use of NRS. Use of NRS should be tailored based on the patient's specific characteristics and type of surgery, aimed at a personalized cost-effective approach.

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).

Hypercarbia and high-flow nasal oxygen use during anaesthesia - risking a failure to thrive?

Prevention of arterial oxygen desaturation during anaesthesia with high-flow nasal oxygen (HFNO) has gained greater acceptance for a widening range of procedures. However, during HFNO use there remains the potential for development of significant anaesthesia-associated apnoea or hypoventilation and the possibility of hypercarbia, with harmful cardiovascular or neurological sequelae. The aim of this study was to determine whether any HFNO-related hypercarbia adverse incidents had been reported on webAIRS, an online database of adverse anaesthesia-related incidents. Two relevant reports were identified of complications due to marked hypercarbia during HFNO use to maintain oxygenation. In both reports, HFNO and total intravenous anaesthesia were used during endoscopic procedures through the upper airway. In both, the extent of hypoventilation went undetected during HFNO use. An ensuing cardiac arrest was reported in one report, ascribed to acute hypercarbia-induced exacerbation of the patient's pre-existing pulmonary hypertension. In the other report, hypercarbia led to a prolonged duration of decreased level of consciousness post procedure, requiring ventilatory support. During the search, an additional 11 reports of postoperative hypercarbia-associated sedation were identified, unrelated to HFNO. In these additional reports an extended duration of severe acute hypercarbia led to sedation or loss of consciousness, consistent with the known effects of hypercarbia on consciousness. These 13 reports highlight the potential dangers of unrecognised and untreated hypercarbia, even if adequate oxygenation is maintained.

Apnoeic oxygenation during neonatal intubation

'Apnoeic oxygenation' describes the diffusion of oxygen across the alveolar-capillary interface in the absence of tidal respiration. Apnoeic oxygenation requires a patent airway, the diffusion of oxygen to the alveoli, and cardiopulmonary circulation. Apnoeic oxygenation has varied applications in adult medicine including facilitating tubeless anaesthesia or improving oxygenation when a difficult airway is known or anticipated. In the paediatric population, apnoeic oxygenation prolongs the time to oxygen desaturation, facilitating intubation. This application has gained attention in neonatal intensive care where intubation remains a challenging procedure. Difficulties are related to the infant's size and decreased respiratory reserve. In addition, policy changes have led to limited opportunities for operators to gain proficiency. Until recently, evidence of benefit of apnoeic oxygenation in the neonatal population came from a small number of infants recruited to paediatric studies. Evidence specific to neonates is emerging and suggests apnoeic oxygenation may increase intubation success and limit physiological instability during the procedure. The best way to deliver oxygen to facilitate apnoeic oxygenation remains an important question.

[THRIVE combined with i-gel laryngeal mask for prolonging apneic oxygenation time in retrograde intrarenal surgery]

OBJECTIVE

To explore the effect of THRIVE combined with i-gel laryngeal mask on the safety of oxygen therapy in apnea and surgical precision of retrograde intrarenal surgery.

METHODS

A total of 120 patients undergoing retrograde intrarenal surgery under general anesthesia with laryngeal mask were randomized into 3 groups (n=40), and after the flexible ureteroscope entered the renal pelvis and located the stones, the patients received assisted ventilation in APPV mode (control group), ventilation with small tidal volume and high respiratory rate (group H), or THRIVE combined with laryngeal mask for oxygen supply without using the ventilator (THRIVE group). The time for lithotripsy by the surgeons, surgeons' satisfaction, diaphragm mobility, and times of urinary tract mucosal injury were recorded, and arterial blood pressure, heart rate, SpO2, PaO2, PaCO2, and pH value were measured before, during and after lithotripsy.

RESULTS

Among the 3 groups, THRIVE group had the shortest time for lithotripsy, best satisfaction of the surgeons, the lowest diaphragmatic mobility of the patients, and the smallest number of mucosal injuries. The arterial blood pressure, heart rate, and SpO2 of the patients did not differ significantly among the 3 groups. At 20 min and 30 min after the start of lithotripsy, PaO2 decreased significantly in group H and THRIVE group; in THRIVE group, PaCO2 increased and pH decreased significantly at 10, 20 and 30 min after the start of lithotripsy. No significant difference was found in oxygenation indicators among the 3 groups upon discharge from the PACU.

CONCLUSION

In retrograde intrarenal surgery, THRIVE combined with i- gel laryngeal mask for oxygen therapy during the anaerobic period can improve the surgical accuracy and maintain the patient's oxygenation index in a controllable range within 30 min.

Safety and Utility of Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) for Laser Laryngeal Surgery

OBJECTIVE

Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) is gaining acceptance as a safe method for apneic ventilation and oxygenation during laryngeal procedures, but remains controversial during laser laryngeal surgery (LLS) due to the theoretical risk of airway fire. This study describes our experience with THRIVE during LLS.

STUDY DESIGN

Retrospective cohort study.

SETTING

Stanford University Hospital, October 15, 2015 to June 1, 2021.

METHODS

Retrospective chart review of patients ≥18 years who underwent LLS involving the CO2 or KTP laser with THRIVE as the primary mode of oxygenation.

RESULTS

A total of 172 cases were identified. 20.9% were obese (BMI ≥ 30). Most common operative indication was subglottic stenosis. The CO2 laser was used in 79.1% of cases. Median lowest intraoperative SpO2 was 96%. 44.7% cases were solely under THRIVE while 16.3% required a single intubation and 19.2% required multiple intubations. Mean apnea time for THRIVE only cases was 32.1 minutes and in cases requiring at least one intubation 24.0 minutes (p < .001). Mean apnea time was significantly lower for patients who were obese (p < .001) or had a diagnosis of hypertension (p = .016). Obese patients and patients with hypertension were 2.03 and 1.43 times more likely to require intraoperative intubation, respectively. There were no intraoperative complications or fires since the institution of our LLS safety protocol.

CONCLUSION

By eliminating the fuel component of the fire triangle, THRIVE can be safely used for continuous delivery of high FiO2 during LLS, provided adherence to institutional THRIVE-LLS protocols.

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.

Cerebral Oxygenation during Neonatal Intubation with Nasal High Flow: A Sub-Study of the SHINE Randomized Trial

INTRODUCTION

Nasal high flow (nHF) improves the likelihood of successful neonatal intubation on the first attempt without physiological instability. The effect of nHF on cerebral oxygenation is unknown. The aim of this study was to compare cerebral oxygenation during endotracheal intubation in neonates receiving nHF and those receiving standard care.

METHODS

A sub-study of a multicentre randomized trial of nHF during neonatal endotracheal intubation. A subset of infants had near-infrared spectroscopy (NIRS) monitoring. Eligible infants were randomly assigned to nHF or standard care during the first intubation attempt. NIRS sensors provided continuous regional cerebral oxygen saturation (rScO2) monitoring. The procedure was video recorded, and peripheral oxygen saturation and rScO2 data were extracted at 2-second intervals. The primary outcome was the average difference in rScO2 from baseline during the first intubation attempt. Secondary outcomes included average rScO2 and rate of change of rScO2.

RESULTS

Nineteen intubations were analyzed (11 nHF; 8 standard care). Median (interquartile range [IQR]) postmenstrual age was 27 (26.5-29) weeks, and weight was 828 (716-1,135) g. Median change in rScO2 from baseline was -1.5% (-5.3 to 0.0) in the nHF group and -9.4% (-19.6 to -4.5) in the standard care group. rScO2 fell more slowly in infants managed with nHF compared with standard care: median (IQR) rScO2 change -0.08 (-0.13 to 0.00) % per second and -0.36 (-0.66 to -0.22) % per second, respectively.

CONCLUSIONS

In this small sub-study, regional cerebral oxygen saturation was more stable in neonates who received nHF during intubation compared with standard care.

Non-intubated deep paralysis: a new anaesthesia strategy for vocal cord polypectomy

BACKGROUND

Vocal cord polyp is common otorhinolaryngological disease, traditionally treated by vocal cord polypectomy under a supporting laryngoscope with general anaesthesia. Although it is safe and controllable, it would cause some anaesthesia complications. Moreover, the complex process of general anaesthesia may significantly reduce surgical efficiency. Avoiding these problems remains an important issue.

METHODS

All patients were subjected to the standard non-intubated deep paralysis (NIDP) protocol consisting of four phases. An emergency plan was launched when NIDP cannot be implemented successfully. Patient characteristics, blood gas and monitoring data were collected during NIDP. Data concerning satisfaction, complications and duration of anaesthesia and recovery were collected to assess its effectiveness.

RESULT

Among 20 enrolled patients, the success rate of NIDP was 95%. Only one patient failed in completing NIDP. Blood gas analysis revealed that the partial pressure of oxygen and carbon dioxide was maintained at safe levels. Monitoring during NIDP revealed fluctuations in mean arterial pressure between 110 and 70 mmHg, and the heart rate was stable at 60-100 beats per minute. The duration of anaesthesia and postoperative recovery were 13.0 ± 2.84 and 5.47 ± 1.97 min, respectively. All patients and surgeons were satisfied with NIDP, and no complications were detected before discharge.

CONCLUSION

NIDP can be safely applied to patients and can replace general anaesthesia in vocal cord polypectomy. It can significantly reduce the duration of anaesthesia and postoperative recovery. No anaesthesia complications occurred without intubation, and patients and surgeons were satisfied with NIDP.

TRIAL REGISTRATIONS

This single-centre, prospective study was registered on clinicaltrial.gov (NCT04247412) on 30^th July 2020.

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.

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

BACKGROUND

Obesity is a risk factor for airway-related incidents during anaesthesia. High-flow nasal oxygen has been advocated to improve safety in high-risk groups, but its effectiveness in the obese population is uncertain. This study compared the effect of high-flow nasal oxygen and low-flow facemask oxygen delivery on duration of apnoea in morbidly obese patients.

METHODS

Morbidly obese patients undergoing bariatric surgery were randomly allocated to receive either high-flow nasal (70 L min^-1) or facemask (15 L min^-1) oxygen. After induction of anaesthesia, the patients were apnoeic for 18 min or until peripheral oxygen saturation decreased to 92%.

RESULTS

Eighty patients were studied (41 High-Flow Nasal Oxygen, 39 Facemask). The median apnoea time was 18 min in both the High-Flow Nasal Oxygen (IQR 18-18 min) and the Facemask (inter-quartile range [IQR], 4.1-18 min) groups. Five patients in the High-Flow Nasal Oxygen group and 14 patients in the Facemask group desaturated to 92% within 18 min. The risk of desaturation was significantly lower in the High-Flow Nasal Oxygen group (hazard ratio=0.27; 95% confidence interval [CI], 0.11-0.65; P=0.007).

CONCLUSIONS

In experienced hands, apnoeic oxygenation is possible in morbidly obese patients, and oxygen desaturation did not occur for 18 min in the majority of patients, whether oxygen delivery was high-flow nasal or low-flow facemask. High-flow nasal oxygen may reduce desaturation risk compared with facemask oxygen. Desaturation risk is a more clinically relevant outcome than duration of apnoea. Individual physiological factors are likely to be the primary determinant of risk rather than method of oxygen delivery.

CLINICAL TRIAL REGISTRATION

NCT03428256.

High-flow nasal oxygen for suspension laryngoscopy: a multicenter open-label study

In this study, we aimed to assess the efficacy of high-flow nasal oxygen (HFNO) to maintain blood peripheral oxygen saturation (SpO2) in patients undergoing suspension laryngoscopy under general anesthesia. Adult patients were included in this bicenter study. After face-mask oxygenation, HFNO at a flow rate of 70 L min^-1 and fraction of inspired oxygen 100% was initiated at loss of consciousness. At the end of HFNO, blood gas analysis was performed. Of the 29 included patients, five (17.2%; 95% confidence interval [CI]: 7.6-34.5) presented SpO2 <95% during the first 15 minutes of the procedure and eight patients (27.6%; 95% CI: 14.7-45.7) presented SpO2 <95% throughout the procedure. Six patients (20.7%; 95% CI: 9.8-38.4) required rescue jet ventilation. Median apnea time before SpO2 <95% was 13.5 (interquartile range [IQR]: 10-17.7) minutes. Arterial carbon dioxide tension at the end of the procedure or at the time of study discontinuation was 9.73 (IQR: 8.8-10.9) kPa and was higher than 8 kPa in 88.9% (95% CI: 71.9-96.1) of patients. HFNO was associated with a relatively high incidence of suboptimal oxygen saturation and hypercapnia during suspension laryngoscopy under general anesthesia and may not be considered the reference technique.

Incidence of oxygen desaturation using a high-flow nasal cannula versus a facemask during flexible bronchoscopy in patients at risk of hypoxemia: a randomised controlled trial

BACKGROUND

Patients with obstructive sleep apnoea (OSA), male sex, obesity, older age or hypertension are prone to hypoxemia during flexible bronchoscopy. This study investigated whether using a high-flow nasal cannula (HFNC) could reduce the incidence of oxygen desaturation during bronchoscopy under deep sedation in patients at risk of hypoxemia.

METHODS

A total of 176 patients at risk of hypoxemia who underwent flexible bronchoscopy under deep sedation were randomly assigned to two groups: the HFNC group (humidified oxygen was supplied via a high-flow nasal cannula at a rate of 60 L/min and a concentration of 100%, n = 87) and the facemask group (oxygen was supplied via a tight-fitting facemask at a rate of 6 L/min and a concentration of 100%, n = 89).

RESULTS

Oxygen desaturation occurred in 4 (4.6%) patients in the HFNC group and 26 (29.2%) patients in the facemask group (P < 0.001). The facemask group required more jaw thrust manoeuvres than the HFNC group (43[48.3%] vs. 5[5.7%], P < 0.001). 8 patients (9.0%) in the facemask group and none in the HFNC group required bag-mask ventilation (P = 0.012).

CONCLUSION

The use of an HFNC can reduce the incidence of oxygen desaturation and the requirement for airway intervention in patients at risk of hypoxemia during flexible bronchoscopy under deep sedation.

TRIAL REGISTRATION

www.chiCTR.org.cn Identifier: ChiCTR2100044105. Registered 11/03/2021.

Subglottic tracheal stenosis complicating pregnancy: A case report

The case presented details an uncommon case of subglottic tracheal stenosis exacerbated by pregnancy. We outine the multidisciplinary management involved and the outcomes for the pregnancy. The case serves as a reminder that shortness of breath in pregnancy has a broad differential diagnosis, and stridor is always abnormal.

High-flow nasal cannula versus standard low-flow nasal cannula during deep sedation in patients undergoing radiofrequency atrial fibrillation catheter ablation: a single-centre randomised controlled trial

Background

To our knowledge, there are few trials studying the effect of high-flow nasal cannula (HFNC) during deep sedation. Our hypothesis is that high-flow nasal cannula (HFNC) will prevent hypoxemia and desaturation as compared to low-flow nasal cannula (LFNC) during prolonged deep sedation in patients with atrial fibrillation undergoing radiofrequency catheter ablation (RFCA).

Methods

A single-centre, randomised controlled trial with HFNC as the intervention and LFNC as the control group. A total of 94 adult patients per group undergoing elective radiofrequency atrial fibrillation catheter ablation under deep sedation. will be included. The primary outcome is the lowest oxygen saturation (SpO2). Secondary outcomes are as follows: the duration of lowest SpO2, cross over from oxygen therapy in both directions, incidence of SpO2 below 90% > 60 seconds, adverse sedation events, adverse effects of HFNC, mean CO2, peak CO2 and patients experience with oxygen therapy. The study will take place during the 2-day admission period for RFCA. Patients can fill out their questionnaires in the first week after treatment.

Discussion

HFNC is increasingly used as a technique for oxygen delivery in procedural sedation and analgesia. We hypothesise that HFNC is superior to the standard treatment LFNC in patients under deep sedation with respect to the incidence of desaturation. To our knowledge, there are no adequately powered clinical trial studies on the effects of HFNC in prolonged deep sedation.

Trial registration

ClinicalTrials.gov NCT04842253. Registered on 04 April 2021

Nasal High-Flow Therapy during Neonatal Endotracheal Intubation

BACKGROUND

Neonatal endotracheal intubation often involves more than one attempt, and oxygen desaturation is common. It is unclear whether nasal high-flow therapy, which extends the time to desaturation during elective intubation in children and adults receiving general anesthesia, can improve the likelihood of successful neonatal intubation on the first attempt.

METHODS

We performed a randomized, controlled trial to compare nasal high-flow therapy with standard care (no nasal high-flow therapy or supplemental oxygen) in neonates undergoing oral endotracheal intubation at two Australian tertiary neonatal intensive care units. Randomization of intubations to the high-flow group or the standard-care group was stratified according to trial center, the use of premedication for intubation (yes or no), and postmenstrual age of the infant (≤28 or >28 weeks). The primary outcome was successful intubation on the first attempt without physiological instability (defined as an absolute decrease in the peripheral oxygen saturation of >20% from the preintubation baseline level or bradycardia with a heart rate of <100 beats per minute) in the infant.

RESULTS

The primary intention-to-treat analysis included the outcomes of 251 intubations in 202 infants; 124 intubations were assigned to the high-flow group and 127 to the standard-care group. The infants had a median postmenstrual age of 27.9 weeks and a median weight of 920 g at the time of intubation. A successful intubation on the first attempt without physiological instability was achieved in 62 of 124 intubations (50.0%) in the high-flow group and in 40 of 127 intubations (31.5%) in the standard-care group (adjusted risk difference, 17.6 percentage points; 95% confidence interval [CI], 6.0 to 29.2), for a number needed to treat of 6 (95% CI, 4 to 17) for 1 infant to benefit. Successful intubation on the first attempt regardless of physiological stability was accomplished in 68.5% of the intubations in the high-flow group and in 54.3% of the intubations in the standard-care group (adjusted risk difference, 15.8 percentage points; 95% CI, 4.3 to 27.3).

CONCLUSIONS

Among infants undergoing endotracheal intubation at two Australian tertiary neonatal intensive care units, nasal high-flow therapy during the procedure improved the likelihood of successful intubation on the first attempt without physiological instability in the infant. (Funded by the National Health and Medical Research Council; Australian New Zealand Clinical Trials Registry number, ACTRN12618001498280.).

Efficacy of high-flow nasal oxygenation against peri- and post-procedural hypoxemia in patients with obesity: a meta-analysis of randomized controlled trials

This meta-analysis aimed at investigating the efficacy of high-flow nasal oxygenation (HFNO) against hypoxemia in patients with obesity compared with conventional oxygenation therapy and non-invasive ventilation. Databases were searched from inception to August 2021. Studies involving peri- or post-procedural use of HFNO were included. The primary outcome was risk of hypoxemia, while the secondary outcomes included status of oxygenation and carbon dioxide elimination. Ten randomized controlled trials (RCTs) were included. We found that HFNO prolonged the safe apnea time at induction compared to control group [mean difference (MD) = 73.88 s, p = 0.0004; 2 RCTs] with no difference in risk of peri-procedural hypoxemia [relative risk (RR) = 0.91, p = 0.64; 4 RCTs], minimum SpO2 (MD = 0.09%, p = 0.95; 4 RCTs), PaO2 (MD = − 8.13 mmHg, p = 0.86; 3 RCTs), PaCO2 (MD = − 6.71%, p = 0.2; 2 RCTs), EtCO2 (MD = − 0.28 mmHg, p = 0.8; 4 RCTs) between the two groups. HFNO also did not improve postprocedural PaO2/FiO2 ratio (MD = 41.76, p = 0.58; 2 RCTs) and PaCO2 (MD = − 2.68 mmHg, p = 0.07; 2 RCTs). This meta-analysis demonstrated that the use of HFNO may be associated with a longer safe apnea time without beneficial impact on the risk of hypoxemia, oxygenation, and CO2 elimination in patients with obesity. The limited number of trials warranted further large-scale studies to support our findings.

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

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

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.

Noninvasive ventilation in children: A review for the pediatric anesthesiologist

Preserving adequate respiratory function is essential in the perioperative period. Mechanical ventilation with endotracheal intubation is widely used for this purpose. In select patients, noninvasive ventilation (NIV) may be an alternative to invasive ventilation or may complement respiratory management. NIV is used to provide ventilatory support and increase gas exchange at the alveolar level without the use of an invasive artificial airway such as an endotracheal tube or tracheostomy. NIV includes both continuous positive airway pressure (CPAP) and noninvasive positive pressure ventilation. Indications for NIV range from acute hypoxic respiratory failure in the intensive care unit or the emergency department, to chronic respiratory failure in patients with neuromuscular disease with nocturnal hypoventilation. In the perioperative setting, NIV is commonly applied as CPAP, and bilevel positive airway pressure (BPAP). There are limited data on the role of NIV in children in the perioperative setting, and there are no clear guidelines regarding optimal timing of use and pressure settings of perioperative NIV. Contraindications to the use of NIV include reduced level of consciousness, apnea, severe respiratory distress, and inability to maintain upper airway patency or airway protective reflexes. Common problems encountered during NIV involve airway leaks and asynchrony with auto-triggering. High-flow nasal oxygen (HFNO) has emerged as an alternative to NIV when trying to decrease the work of breathing and improve oxygenation in children. HFNO delivers humidified and heated oxygen at rates between 2 and 70 L/min using specific nasal cannulas, and flows are determined by the patient's weight and clinical needs. HFNO can be useful as a method for preoxygenation in infants and children by prolonging apnea time before desaturation, yet in children with decreased minute ventilation or apnea HFNO does not improve alveolar gas exchange. Clinicians experienced with these devices, such as pediatric intensivists and pulmonary medicine specialists, can be useful resources for the pediatric anesthesiologist caring for complex patients on NIV.

Humidified rapid-insufflation ventilatory exchange is a means of oxygenation during rigid bronchoscopy: A case series

Humidified rapid-insufflation ventilatory exchange (HRIVE) is an option for maintenance of oxygenation. This technique allows for oxygenation while the patient is apnoeic due to continuous positive airway pressure and gas exchange through flow-dependent dead space flushing. There is no study about the usage of HRIVE during rigid bronchoscopy. This retrospective study looked at rigid bronchoscopy cases utilizing HRIVE. Data points assessing adequacy of oxygenation and ventilation were recorded at time points: oxygen saturation (SpO2), partial pressure of oxygen (PaO2) and partial pressure of carbon dioxide (PaCO2). Our nine cases had an average baseline SpO2 of 99.26%, 95.56% at 10 min into HRIVE and 95.27% at the end of HRIVE. The average baseline PaO2 was 309.01 mmHg, 124.99 mmHg at 10 min into HRIVE and 128.17 mmHg at the end of HRIVE. The average baseline PaCO2 was 43.26 mmHg, 68.76 mmHg at 10 min into HRIVE and 75.52 mmHg at the end of HRIVE. The average pre-HRIVE end-tidal CO2 (ETCO2) was 38.56 mmHg and the average post-HRIVE ETCO2 was 61.22 mmHg. The average baseline pH was 7.36, 7.22 at 10 min into HRIVE and 7.19 at the end of HRIVE. In this small cohort study, HRIVE was able to maintain adequate oxygenation via the rigid bronchoscope in a select group of patients. Hypercapnia and respiratory acidosis did result after 10 min, which may predispose certain patient populations to complications. HRIVE potentially offers an additional option of oxygenation via the rigid bronchoscope.

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

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.

Biomarkers for oxidative stress and organ injury during Transnasal Humidified Rapid-Insufflation Ventilatory Exchange compared to mechanical ventilation in adults undergoing microlaryngoscopy: A randomised controlled study

BACKGROUND

Apnoeic oxygenation using Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) during general anaesthesia prolongs the safe apnoeic period. However, there is a gap of knowledge how THRIVE-induced hyperoxia and hypercapnia impact vital organs. The primary aim of this randomised controlled trial was to characterise oxidative stress and, secondary, vital organ function biomarkers during THRIVE compared to mechanical ventilation (MV).

METHODS

Thirty adult patients, American Society of Anesthesiologists (ASA) 1-2, undergoing short laryngeal surgery under general anaesthesia were randomised to THRIVE, F_I O₂ 1.0, 70 L min^-1 during apnoea or MV. Blood biomarkers for oxidative stress, malondialdehyde and TAC and vital organ function were collected (A) preoperatively, (B) at procedure completion and (C) at PACU discharge.

RESULTS

Mean apnoea time was 17.9 (4.8) min and intubation to end-of-surgery time was 28.1 (12.8) min in the THRIVE and MV group, respectively. Malondialdehyde increased from 11.2 (3.1) to 12.7 (3.1) µM (P = .02) and from 9.5 (2.2) to 11.6 (2.6) µM (P = .003) (A to C) in the THRIVE and MV group, respectively. S100B increased from 0.05 (0.02) to 0.06 (0.02) µg L^-1 (P = .005) (A to C) in the THRIVE group. No increase in TAC, CRP, leukocyte count, troponin-T, NTproBNP, creatinine, eGFRcrea or NSE was demonstrated during THRIVE.

CONCLUSION

While THRIVE and MV was associated with increased oxidative stress, we found no change in cardiac, inflammation or kidney biomarkers during THRIVE. Further evaluation of stress and inflammatory response and cerebral and cardiac function during THRIVE is needed.

Application and Efficiency of Transnasal Humidified Rapid-Insufflation Ventilatory Exchange in Laryngeal Microsurgery

OBJECTIVES/HYPOTHESIS

This study aimed to analyze the feasibility of transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) during laryngeal microsurgery (LMS) and investigated its efficiency and application according to the location of the lesion.

STUDY DESIGN

Retrospective chart review.

METHODS

Patients over 20 years of age who underwent LMS without underlying cardiac, pulmonary, or cerebrovascular disease were retrospectively reviewed. Overall, 54 patients with endotracheal intubation (ETI) and 44 patients with THRIVE were included. The operation and anesthesia time, induction and emergence time, oxygen saturation (SpO₂ ), and transcutaneous carbon dioxide (TcCO₂ ) levels were analyzed and compared between the two ventilation methods according to disease subsite.

RESULTS

Compared with ETI, patients with THRIVE presented reduced operation time (16.3 ± 9.69 min vs. 21.9 ± 12.0 min), anesthesia time (33.6 ± 11.4 min vs. 45.4 ± 13.9 min), emergence time (6.73 ± 2.49 min vs. 8.52 ± 3.17 min), without significant decreases in SpO₂ but with increased TcCO₂ (10.9 ± 6.12% vs. 7.33 ± 3.86%). Comparing THRIVE to ETI for lesions at the glottis yielded similar findings, which were particularly more significant. However, lesions above the glottis presented no significant difference for any parameters between THRIVE and ETI groups. Lesions involving multiple subsites and prolonged operation time were risk factors for the intraoperative conversion of ventilation method.

CONCLUSION

THRIVE is reliable for maintaining oxygenation during LMS and is efficient in reducing the operation and emergence times, leading to shorter anesthesia time, especially for lesions at the glottis. However, caution is required administering THRIVE, when lesion involves multiple subsites, and when operation time is prolonged.

LEVEL OF EVIDENCE

3 Laryngoscope, 2021.

[High-flow nasal cannula oxygen therapy can reduce occurrence of hypoxia in elderly patients during anesthesia recovery]

OBJECTIVE

To explore the effect of high-flow nasal cannula (HFNC) oxygen therapy in elderly patients during anesthesia recovery.

METHOD

A total of 178 elderly patients undergoing elective non-cardiac surgeries were randomly assigned into HFNC oxygen therapy group (group H) or nasal cannula oxygen therapy group (group N), with 89 patients in each group.All the patients were admitted in postanesthesia care unit (PACU) after the surgery for recovery following the routine procedure.After trachea extubation, the patients in group H received HFNC oxygen therapy and those in group N had nasal cannula oxygen therapy.In both groups, arterial blood gas analysis was performed at 10 min after oxygen inhalation and the respiratory parameters were recorded.During oxygen inhalation, the occurrence and frequency of hypoxia (oxygen saturation < 90%), trachea reintubation and adverse events (unplanned admission to ICU, vomiting, aspiration, etc.) were recorded.

RESULTS

All the patients recovered safely from anesthesia in the PACU and subsequently received routine care, and only 1 patient in group N required trachea reintubation.Compared with those in group N, that patients in group H had a significantly lower incidence of hypoxia (3.4% vs 11.2%, P=0.044), a higher arterial partial pressure of oxygen (161.96±51.21 vs 114.35±43.60 mmHg, P < 0.001), and a higher oxygenation index(398.76±231.86 vs 324.10±194.16, P=0.021).The mean respiratory rate, arterial partial pressure of carbon dioxide and blood oxygen saturation were all comparable between the two groups.

CONCLUSION

HFNC oxygen therapy during anesthesia recovery is safe and effective in elderly patients and can reduce the occurrence of hypoxia after tracheal extubation and improve arterial partial pressure of oxygen and oxygenation.

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.

High flow nasal oxygen during procedural sedation for cardiac implantable electronic device procedures: A randomised controlled trial

BACKGROUND

High flow nasal oxygen may better support the vulnerable respiratory state of patients during procedural sedation.

OBJECTIVE

The objective of this study was to investigate the effects of high flow nasal oxygen in comparison to facemask oxygen on ventilation during cardiac implantable electronic device procedures performed with procedural sedation.

DESIGN

A randomised controlled trial.

SETTING

The study was conducted at one academic hospital in Canada.

PARTICIPANTS

Adults undergoing elective cardiac implantable electronic device procedures with sedation administered by an anaesthesia assistant, supervised by an anaesthesiologist from August 2019 to March 2020.

INTERVENTIONS

Participants were randomised 1 : 1 to facemask (≥ 8 l · min-1) or high flow nasal oxygen (50 l · min-1 and a 50 : 50 oxygen to air ratio).

MAIN OUTCOME MEASURES

The primary outcome was peak transcutaneous carbon dioxide. Outcomes were analysed using Bayesian statistics.

RESULTS

The 129 participants who were randomised and received sedation were included. The difference in peak transcutaneous carbon dioxide was 0.0 kPa (95% CI -0.17 to 0.18). Minor adverse sedation events were 6.4 times more likely to occur in the high flow nasal oxygen group. This estimate is imprecise (95% CI 1.34 to 42.99). The odds ratio for oxygen desaturation for the high flow nasal oxygen group compared with the facemask group was 1.2 (95% CI 0.37 to 3.75). The difference in satisfaction with sedation scores between groups was 0.0 (95% CI -0.33 to 0.23).

CONCLUSIONS

Ventilation, as measured by TcCO2, is highly unlikely to differ by a clinically important amount between high flow nasal oxygen at 50 l min-1 or facemask oxygen at 8 l min-1. Further research with a larger sample size would be required to determine the optimal oxygen:air ratio when using high flow nasal oxygen during cardiac implantable electronic device procedures performed with sedation.

TRIAL REGISTRATION NUMBER

NCT03858257.

Application of high-flow nasal oxygenation as a rescue therapy in difficult videolaryngoscopic intubation

In difficult airway situations, the next step of the airway management method is selected according to the prior presence of difficulties in mask ventilation and endotracheal intubation. It is important for the practitioner to be calm, quick in judgment, and take action in cases of difficult intubation. Recently, high-flow nasal oxygenation has been rapidly introduced into the anesthesiology field. This technique could extend the safe apnea time to desaturation. Especially, it maintains adequate oxygenation even in apnea and allows time for intubation or alternative airway management. We report two cases in which high-flow nasal oxygenation was implemented in the middle of the induction process after quick judgment by clinicians. High-flow nasal oxygenation was successfully used to assist in prolonging the safe apnea time during delicate airway securing attempts.

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 nasal cannula therapy for initial oxygen administration in acute hypercapnic respiratory failure: study protocol of randomised controlled unblinded trial

Introduction

Acute respiratory failure is a common clinical condition accounting for nearly 116 000 admissions in the UK hospitals. Acute type 2 respiratory failure is also called acute hypercapnic respiratory failure (AHRF) and characterised by an elevated arterial CO₂ level of >6 kPa due to pump failure. Acute exacerbation of chronic obstructive pulmonary disease is the most common cause of AHRF. High-flow nasal therapy (HFNT) is a new oxygen delivery system that uses an oxygen-air blender to deliver flow rates of up to 60 L/min. The gas is delivered humidified and heated to the patient via wide-bore nasal cannula.

Methods and analysis

We hypothesised that HFNC as the initial oxygen administration method will reduce the number of patients with AHRF requiring non-invasive ventilation in patients at 6 hours post intervention when compared with low-flow nasal oxygen (LFO). A randomised single-centre unblinded controlled trial is designed to test our hypothesis. The trial will compare two oxygen administration methods, HFNT versus LFO. Patients will be randomised to one of the two arms if they fulfil the eligibility criteria. The sample size is 82 adult patients (41 HFNT and 41 LFO) presenting to the emergency department.

Ethics and dissemination

Ethical approval was obtained from the Office for Research Ethics Committees Northern Ireland (REC reference: 20/NI/0049). Dissemination will be achieved in several ways: (1) the findings will be presented at national and international meetings with open-access abstracts online and (2) in accordance with the open-access policies proposed by the leading research funding bodies we aim to publish the findings in high-quality peer-reviewed open-access journals.

Trial registration number

The trial was prospectively registered at the clinicaltrials.gov registry (NCT04640948) on 20 November 2020.

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.

[Ultrasound assessment of gastric insufflation in obese patients receiving transnasal humidified rapid-insufflation ventilatory exchange during general anesthesia induction]

OBJECTIVE

To assess the effect of transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) on gastric insufflation during general anesthesia induction in obese patients.

METHODS

Ninety obese patients (BMI 30-39.9 kg/m²) undergoing laparoscopic cholecystectomy under general anesthesia were randomized into 3 groups (n=30) to receive facemask pre- oxygenation followed by face mask ventilation (FMV) after administration of anesthetics (Group M), oxygenation with THRIVE (Group T), or pre-oxygenation with facemask combined with THRIVE followed continuous oxygenation with both FMV and THRIVE after administration of anesthetics (Group M+T). The patients in the latter two groups received continuous oxygen via THRIVE during tracheal intubation. All the patients received real-time ultrasound monitoring of the gastric antrum, and positive gastric insufflation (GI⁺) was defined by the presence of comet-tail artifacts. The cross-sectional area of the gastic antrum (CSA-GA) was measured by ultrasound before and after pre-oxygenation and after intubation. The patients' SpO₂, PaO₂, and PaCO₂ at admission (T₁), 5 min after pre-oxygenation (T₂), 5 min after medication (T₃), and immediately after intubation (T₄) were recorded, and the incidence of postoperative adverse events was assessed.

RESULTS

The incidence of gastric insufflation was significantly higher in Group M and Group M+T than in Group T (P < 0.05). The CSA-GA was significantly greater at T₄ than at T₁ in Group M and Group M+T and in their GI⁺s ubgroups. The GI⁺ subgroups in Group M and Group M+ T had significantly larger CSA-GA at T₄ than the GI^- subgroups (P < 0.05). CSA-GA did not vary significantly during anesthesia induction in Group T (P>0.05). The incidence of grade Ⅰ gastric distension was lower but grade Ⅱ gastric distention was higher in Group M and Group M+T than in Group T (P < 0.05). Group M showed significantly greater variations of PaO₂ at T₃ and T₄ than Group T and Group M+T (P < 0.05).

CONCLUSIONS

Ultrasound monitoring of the comet tail sign and the changes of CSA-GA in the gastric antrum is feasible and reliable for detecting gastrointestinal airflow, and in obese patients, the application of THRIVE for induction of anesthesia can ensure the oxygenation level without further increasing gastric insufflation.

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.

A novel application of Transnasal Humidified Rapid Insufflation Ventilatory Exchange via the oral route in morbidly obese patient during monitored anesthesia care - A case report

Background

Transnasal Humidified Rapid Insufflation Ventilatory Exchange (THRIVE) is used to improve oxygenation, with the added benefit of a smaller increase in CO₂ if self-respiration is maintained with THRIVE. Despite these advantages, the use of THRIVE through a nasal cannula is limited in situations such as epistaxis or a basal skull fracture.

Case

We successful used THRIVE, through the oral route under general anesthesia with spontaneous breathing in a morbidly obese patient (weight, 148 kg; height, 183 cm; body mass index, 44.2 kg/m²) who received transnasal steroid injections due to subglottic stenosis.

Conclusions

THRIVE through the oral route may be an effective novel option, although further studies are needed.

A multicentre, randomised trial of stabilisation with nasal high flow during neonatal endotracheal intubation (the SHINE trial): a study protocol

INTRODUCTION

Neonatal endotracheal intubation is an essential but potentially destabilising procedure. With an increased focus on avoiding mechanical ventilation, particularly in preterm infants, there are fewer opportunities for clinicians to gain proficiency in this important emergency skill. Rates of successful intubation at the first attempt are relatively low, and adverse event rates are high, when compared with intubations in paediatric and adult populations. Interventions to improve operator success and patient stability during neonatal endotracheal intubations are needed. Using nasal high flow therapy extends the safe apnoea time of adults undergoing upper airway surgery and during endotracheal intubation. This technique is untested in neonates.

METHODS AND ANALYSIS

The Stabilisation with nasal High flow during Intubation of NEonates (SHINE) trial is a multicentre, randomised controlled trial comparing the use of nasal high flow during neonatal intubation with standard care (no nasal high flow). Intubations are randomised individually, and stratified by site, use of premedications, and postmenstrual age (<28 weeks' gestation; ≥28 weeks' gestation). The primary outcome is the incidence of successful intubation on the first attempt without physiological instability of the infant. Physiological instability is defined as an absolute decrease in peripheral oxygen saturation >20% from preintubation baseline and/or bradycardia (<100 beats per minute).

ETHICS AND DISSEMINATION

The SHINE trial received ethical approval from the Human Research Ethics Committees of The Royal Women's Hospital, Melbourne, Australia and Monash Health, Melbourne, Australia. The trial is currently recruiting in these two sites. The findings of this study will be disseminated via peer-reviewed journals and presented at national and international conferences.

TRIAL REGISTRATION NUMBER

ACTRN12618001498280.