Can We Finally Take the "VE" Out of THRIVE?

Cadaveric Study on the Safety of High-Flow Nasal Oxygen in Laser Microlaryngeal Surgery

INTRODUCTION

High-flow nasal oxygen (HFNO), or transnasal humidified rapid-insufflation ventilatory exchange (THRIVE), is a technique providing apneic oxygenation and a degree of ventilation during microlaryngeal surgery. Its use with laser has been questioned due to concern for airway fire. For fire to occur, a triad of ignition source, oxidizer, and fuel source must be present. By using HFNO and eliminating an endotracheal tube (fuel source), it is hypothesized that airway fire risk is minimal. We tested this theory with human cadavers using HFNO with increasing levels of FiO2 while performing microlaryngeal laser surgery.

METHODS

HFNO was placed on two cadavers, and oxygen was administered at incrementally increasing fraction of inspired oxygen (FiO2) concentrations (30%-100%). Laryngeal microsurgery was conducted with CO2 and KTP lasers applied for 30 s. Oxygen readings were taken at several anatomic locations along the body assessing oxygen concentrations in correlation with increasing FiO2 administration.

RESULTS

The use of CO2 and KTP laser on cadaveric vocal folds produced char but no spark or airway fire at any of the tested oxygen concentrations. Apart from the mouth, there was minimal increase in oxygen levels at the surrounding anatomic sites despite elevating FiO2 levels.

CONCLUSION

HFNO may be safe to use during microlaryngeal laser surgery. By eliminating the endotracheal tube as a fuel source, risk of airway fire may be negligible. Our study safely applied CO2 and KTP lasers for an uninterrupted 30 s with HFNO at 70 L/min and 100% FiO2 producing no spark or fire.

LEVEL OF EVIDENCE

NA Laryngoscope, 2024.

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.

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.