A Retrospective Analysis of Oxygen Desaturation during Acoustic Respiratory Rate Monitoring in Non-ICU Patients following Tracheal Extubation after General Anesthesia

A new index, Respiratory Insufficiency index and Modified Early Warning Scores predict extubation failure

Background

Extubation failure occurs in 5%-20% of patients and is associated with poor clinical outcomes. The primary aim of this project was to determine the predictive ability of the Respiratory Insufficiency (RI) index, Respiratory Oxygenation (ROX) index and Modified Early Warning Score (MEWS) in identifying extubation failure.

Methods

This was a secondary analysis of a prior cross-sectional retrospective study conducted from February 2018 through December 2018 among adult subjects who received mechanical ventilation for more than 24 h. Extubation failure was defined as the need for reintubation or rescue non-invasive ventilation (NIV) within 48 h after planned extubation. Univariate analysis and logistic regression were used to identify the predictors and final model was validated using 10-fold cross validation. Nomogram was constructed based on the final model.

Results

Of 216 enrolled subjects, 46 (21.3%) experienced extubation failure. The median RI index 1-h post extubation was 20 [interquartile range [IQR] 16.33-24.24] for success group and 27.02 [IQR 22.42-33.83] for the failure group (P<0.001). The median ROX index 1-h post extubation was 16.66 [IQR 12.57-19.84] for success group and 11.11 [IQR 8.09-14.67] for failure group (P<0.001). The median MEWS 1-h post extubation was 2 [IQR 1-3] for the success group and 4 [IQR 3-5] for the failure group (P<0.001). In multivariable analysis, age >60 years [OR 3.89 (95% CI 1.56-9.73); P=0.004], MEWS >4 [OR 4.01 (95% CI (1.59-10.14); P=0.003] and, RI index >20 [OR 4.50 (95% CI 1.43-14.21); P=0.010] were independently associated with extubation failure.

Conclusion

In the present study, RI index and MEWS were independently associated with predicting extubation failure within 1 h of extubation. A prospective validation study is warranted to establish the role of these indices in predicting extubation outcome.

Predictors of hypoxemia after general anesthesia in the early postoperative period in a hospital in Ethiopia: an observational study

BACKGROUND

Early postoperative hypoxemia is a common problem after general anesthesia. The identification of factors associated with an increased occurrence of it might help healthcare professionals to hypoxemia risk patients, therefore this study aims to assess the incidence and factors associated with early postoperative hypoxemia among surgical procedures.

METHODS

A prospective cohort study design was conducted from February 1, 2020 to June 30, 2020, on a total of 424 patients who underwent surgery under general anesthesia in Debre Tabor Comprehensive Specialized Hospital. The data was collected using a structured checklist. Bivariable and multivariable logistic regressions were used to check the association.

RESULTS

The incidence of early postoperative hypoxemia was 45.8%. Patients having a BMI of 25-29.9 kg/m2 and BMI of 30-39.9 kg/m2, patients having a chronic disease, current smokers, SPO2 reading before induction of less than 95%, emergency surgery, and the absence of oxygen therapy during the period of transfer and/or in the post anesthesia care unit were significantly associated with an increased risk of hypoxemia in the early postoperative period.

CONCLUSIONS

The incidence of early postoperative hypoxemia was high in Debre Tabor Comprehensive Specialized Hospital. Obese patients, patients having a chronic disease, current smokers, and lower oxygen saturations before induction, emergency surgery, and the absence of oxygen therapy were the main predictors of an increased occurrence of early postoperative hypoxemia.

Risk factors for bradypnea in a historical cohort of surgical patients receiving fentanyl-based intravenous analgesia

Introduction

The use of both pulse oximetry (SpO₂) and respiration rate (RR) monitoring is recommended to prevent the development of respiratory deterioration, particularly after extubation and narcotic analgesic use for pain management. In this study, we investigated the factors contributing to the development of bradypnea in surgical patients receiving fentanyl-based intravenous analgesia after general anesthesia.

Methods

This study involved a historical chart review of postoperative patients outside an intensive care unit setting. We divided the patients according to the data collected during the first hour postoperatively, into those developing bradypnea (RR < 8 breaths per min for > 2 min) and those with normal RR under oxygen administration. We defined oxygen desaturation as SpO₂ < 90% for > 10 s. We calculated the effect-site concentrations for fentanyl at the end of surgery and 1 h postoperatively using custom-made software based on chart records. A multivariable analysis was used to determine bradypnea-associated explanatory factors.

Results

For the final analysis, we included 258 patients. We detected bradypnea in 125 patients (48%) and oxygen desaturation in 46 patients (18%). We found no difference in the effect-site fentanyl concentrations between patients with and without bradypnea. The logistic regression model revealed that liver dysfunction [odds ratio (OR), 2.918; 95% confidence interval (CI), 1.329–6.405], renal dysfunction (OR, 0.349; 95% CI, 0.128–0.955), and smoking history (OR, 0.236; 95% CI, 0.075–0.735) were independently associated with bradypnea. We found similar incidences of oxygen desaturation between the groups.

Conclusions

Bradypnea was observed in 48% of postoperative patients receiving fentanyl-based intravenous analgesia under oxygen therapy. According to our results, impaired liver function associated positively, whereas smoking history associated negatively with its development. Renal dysfunction was paradoxically associated with less incidence of bradypnea.