Reproducibility of laryngeal force sensor measurements.

OBJECTIVE: The laryngeal force sensor (LFS) measures force during suspension microlaryngoscopy (SML) procedures, and has been previously shown to predict postoperative complications. Reproducibility of its measurements has not been described. STUDY DESIGN: Prospective cohort study. SETTING: Academic medical center. METHODS: 291 adult patients had force data collected from 2017 to 2021 during various SML procedures. 94 patients had passive LFS monitoring (surgeon blinded to intraoperative recordings) and 197 had active LFS monitoring (surgeon able to see LFS recordings). 27 of these patients had repeat procedures, with unique LFS metrics for each procedure. The 27 patients were divided into three groups. Group 1 had passive use for both procedures, group 2 had passive use for the first procedure and active use for the second, and group 3 had active use for both procedures. Force metrics from the two procedures were compared with a paired samples t-test. RESULTS: For airway dilation procedures and cancer resection procedures, average force variances were significantly lower with active versus passive use of the LFS. Group 1-no significant changes in maximum force (procedure 1 = 163.8 N, procedure 2 = 133.8 N, p = 0.324) or average force (procedure 1 = 93.6 N, procedure 2 = 78.3 N, p = 0.617). Group 2-maximum force dropped by 35 % between procedures 1 (219.2 N) and 2 (142.5 N), p = 0.013. Average force dropped by 42.5 % between procedures 1 (147.2 N) and 2 (84.6 N), p = 0.007. Group 3-no significant changes in maximum force (procedure 1 = 158.6 N, procedure 2 = 158.2 N, p = 0.986) or average force (procedure 1 = 94.2, procedure 2 = 81.8, p = 0.419). CONCLUSIONS: LFS measurements were reproducible for similar procedures in the same patient when the type of LFS monitoring was not a confounder.

Post-anesthesia care unit desaturation in adult deep extubation patients.

OBJECTIVE: Deep extubation refers to endotracheal extubation performed while a patient is deeply anesthetized and without airway reflexes. After deep extubation, patients are sent to the post-anesthesia care unit (PACU) to recover, an area with notably different management and staffing than the operating room (OR). One of the most frequent and concerning complications to occur in the PACU is hypoxemia. As such, this study seeks to evaluate the incidence of desaturation, defined by SpO2 < 90% for longer than 10 s, in the PACU following deep extubation. Additionally, we hope to assess the consequence of desaturation on perioperative workflow by comparing PACU recovery times. RESULTS: Following deep extubation, 4.3% of patients (13/300) experienced desaturation in the PACU. Every episode was notably minor, with patients reverting to normal saturation levels within a minute. Of the 26 case factors assessed, 24 had no significant association desaturation in the PACU, including the amount of time spent in the PACU. History of asthma was the only statistically significant factor found to be positively associated with desaturation. We find that PACU desaturation episodes following deep extubation are rare. Our findings suggest that deep extubation is a viable and safe option for patients without significant respiratory tract pathology.

Laryngeal Force Sensor for Suspension Microlaryngoscopy: A Prospective Controlled Trial.

OBJECTIVES: The laryngeal force sensor (LFS) provides real-time force data for suspension microlaryngoscopy. This study investigates whether active use of the LFS can prevent the development of complications. STUDY DESIGN: Prospective controlled trial. SETTING: Academic tertiary center. METHODS: The LFS and custom software were developed to track intraoperative force metrics. A consecutive series of 100 patients had force data collected with operating surgeons blinded to intraoperative readings. The subsequent 100 patients had surgeons actively use the LFS monitoring system. Patients were prospectively enrolled, completing pre- and postoperative surveys to assess the development of tongue pain, paresthesia, paresis, dysgeusia, or dysphagia. RESULTS: On univariate analysis, the active monitoring group had lower total impulse (P < .001) and fewer extralaryngeal complications (P < .01). On multiple logistic regression, maximum force (odds ratio [OR], 1.08; 95% CI, 1.01-1.16; P = .02) was a significant predictive variable for the development of postoperative complications. Similarly, active LFS monitoring showed a 29.1% (95% CI, 15.7%-42.4%; P < .001) decrease in the likelihood of developing postoperative complications. These effects persisted at the first postoperative visit for maximum force (P = .04) and active LFS monitoring (P = .01). Maximum force (OR, 1.11; 95% CI, 1.04-1.18; P < .01) and active LFS monitoring (16.6%; 95% CI, 2.7%-30.5%; P = .02) were also predictive for the development of an abnormal 10-item Eating Assessment Tool score. These effects also persisted at the first postoperative visit for maximum force (P = .01) and active LFS monitoring (P = .01). CONCLUSION: Maximum force is predictive of the development postoperative complications. Active monitoring with the LFS is able to mitigate these forces and prevent postoperative complications. LEVEL OF EVIDENCE: 2.

Force Metrics and Suspension Times for Microlaryngoscopy Procedures.

OBJECTIVE: To determine the difference in force metrics measured by the laryngeal force sensor for various suspension microlaryngoscopy (SML) procedures and their perioperative narcotic requirements. STUDY DESIGN: Prospective observational study. SETTING: Academic tertiary center. METHODS: The laryngeal force sensoris a force sensor designed for SML procedures. Prospectively enrolled patients had dynamic recordings of maximum force, average force, suspension time, and total impulse. Procedures were grouped into excision of striking zone lesions, nonstriking zone lesions, endoscopic cancer surgery with margin control, and airway dilation. Narcotic administration in the intraoperative period and postanesthesia care unit was also recorded and converted into IV morphine equivalents. Surgeons were blinded to the force recordings during surgery to prevent operator bias. RESULTS: In total, 110 patients completed the study. There was no significant difference in average force across different procedures, however, a significant difference was seen for maximum force (P = 0.025), suspension time (P < 0.001), and total impulse (P = 0.002). The highest values were seen for endoscopic cancer surgeries with margin control with a mean maximum force of 49.4 lbf (95%CI, 37.1-61.7), mean suspension time of 60.2 minutes (95%CI, 40.5-79.9), and mean total impulse of 31.3 ton*s (95%CI, 15.2-47.3). A significant difference (P < 0.01) in perioperative narcotic requirements was also seen, with endoscopic cancer surgery cases having the highest requirements at 27.6 mg of ME (95%CI, 16.1-39.2 mg). CONCLUSION: Significant differences in force metrics exist between various SML procedures. Endoscopic cancer surgery is associated with higher force metrics and perioperative narcotic requirements.

Incidence of airway complications associated with deep extubation in adults.

BACKGROUND: Endotracheal extubation is the most crucial step during emergence from general anesthesia and is usually carried out when patients are awake with return of airway reflexes. Alternatively, extubations can also be accomplished while patients are deeply anesthetized, a technique known as "deep extubation", in order to provide a "smooth" emergence from anesthesia. Deep extubation is seldomly performed in adults, even in appropriate circumstances, likely due to concerns for potential respiratory complications and limited research supporting its safety. It is in this context that we designed our prospective study to understand the factors that contribute to the success or failure of deep extubation in adults. METHODS: In this prospective observational study, 300 patients, age ≥ 18, American Society of Anesthesiologists Physical Status (ASA PS) Classification I - III, who underwent head-and-neck and ocular surgeries. Patients' demographic, comorbidity, airway assessment, O2 saturation, end tidal CO2 levels, time to exit OR, time to eye opening, and respiratory complications after deep extubation in the OR were analyzed. RESULTS: Forty (13%) out of 300 patients had at least one complication in the OR, as defined by persistent coughing, desaturation SpO2 < 90% for longer than 10s, laryngospasm, stridor, bronchospasm and reintubation. When comparing the complication group to the no complication group, the patients in the complication group had significantly higher BMI (30 vs 26), lower O2 saturation pre and post extubation, and longer time from end of surgery to out of OR (p < 0.05). CONCLUSIONS: The complication rate during deep extubation in adults was relatively low compared to published reports in the literature and all easily reversible. BMI is possibly an important determinant in the success of deep extubation.

Laryngeal force sensor metrics are predictive of increased perioperative narcotic requirements.

OBJECTIVES/HYPOTHESIS: To determine the relationship between force metrics measured by the laryngeal force sensor (LFS) during suspension microlaryngoscopy (SML) and perioperative narcotic requirements. STUDY DESIGN: Prospective observational study. METHODS: Compressive tissue forces were recorded during SML using the LFS and correlated with postoperative narcotic requirements in the postanesthesia care unit (PACU) at an academic tertiary center. Patients were prospectively enrolled and had force metrics recorded throughout each procedure including maximum force, average force, suspension time, and total impulse. Narcotic administration in the intraoperative period and PACU were also recorded and converted into intravenous morphine equivalents (ME). Surgeons were blinded to the force recordings during surgery to prevent operator bias. RESULTS: Eighty-two patients completed the study. Of these patients, the mean perioperative ME requirement was 16.96 mg (range, 0.15-79.82 mg). Univariate analysis demonstrated a positive correlation between perioperative narcotic requirements and total suspension time (P < .001) as well as total impulse (P = .007). A positive correlation was also seen with maximum force, although not significantly. On multiple linear regression, total suspension time was a significant predictive variable for perioperative narcotic use, with a marginal incremental increase of 0.273 mg of ME per minute of total suspension time (0.273 mg/min, 95% confidence interval: 0.040-0.507 mg/min, P = .022). CONCLUSIONS: Intraoperative force metrics including total suspension time are predictive of increased perioperative narcotic requirement after SML. Total impulse during SML may also correlate with increased perioperative narcotic requirements. LEVEL OF EVIDENCE: 2 Laryngoscope, 129:2563-2567, 2019.