Correlation of Perioperative Atelectasis With Duration of Anesthesia, Pneumoperitoneum, and Length of Surgery in Patients Undergoing Laparoscopic Cholecystectomy

Ultrasonographic evaluation of diaphragmatic excursion changes after major laparoscopic surgeries in the Trendelenburg position under general anaesthesia: A prospective observational study

Background and Aims

Laparoscopic surgeries result in increased intra abdominal pressure and cephalad displacement of the diaphragm. The Trendelenburg position can augment these respiratory changes. The primary objective of this study was to compare diaphragmatic excursions before and after a major laparoscopic pelvic surgery under general anaesthesia in the Trendelenburg position using ultrasonography (USG).

Methods

This prospective observational study included 90 patients of either gender, aged 20-60 years, with American Society of Anesthesiologists physical status I/II. M-mode USG was used to assess diaphragm inspiratory amplitude (DIA) before induction of anaesthesia and 10 minutes after tracheal extubation. Factors such as age, gender, body mass index, positive end-expiratory pressure (PEEP), pain, peak airway pressures, duration of pneumoperitoneum, duration and degree of Trendelenburg position and duration of anaesthesia were recorded. Pearson's correlation and multiple linear regression were used to analyse the factors affecting change in DIA (ΔDIA).

Results

The mean difference (95% confidence interval (CI)) of measured DIA was 0.70 (0.598-0.809), P < 0.001. ΔDIA had a weak positive significant correlation with age, anaesthesia duration, pneumoperitoneum, and visual analogue scale (VAS) score 10 minutes after extubation. Multiple linear regression analysis showed 14.86% of the variance in DIA. Age (β = 0.008, P = 0.049), duration of anaesthesia (β = 0.002, P = 0.02) and VAS score 10 minutes after extubation (β = 0.128, P = 0.001) were significant independent predictors.

Conclusion

DIA decreased significantly after pelvic laparoscopic surgeries performed in the Trendelenburg position. Age, duration of anaesthesia and pain after the procedure were significant independent predictors.

The role of ultrasound in predicting non-invasive ventilation outcomes: a systematic review

Purpose

To systematically review and compare ultrasonographic methods and their utility in predicting non-invasive ventilation (NIV) outcomes.

Methods

A systematic review was performed using the PubMed, Medline, Embase, and Cochrane databases from January 2015 to March 2023. The search terms included the following: ultrasound, diaphragm, lung, prediction, non-invasive, ventilation, and outcomes. The inclusion criteria were prospective cohort studies on adult patients requiring non-invasive ventilation in the emergency department or inpatient setting.

Results

Fifteen studies were analyzed, which comprised of 1,307 patients (n = 942 for lung ultrasound score studies; n = 365 patients for diaphragm dysfunction studies). Lung ultrasound scores (LUS) greater than 18 were associated with NIV failure with a sensitivity 62-90.5% and specificity 60-91.9%. Similarly, a diaphragm thickening fraction (DTF) of less than 20% was also associated with NIV failure with a sensitivity 80-84.6% and specificity 76.3-91.5%.

Conclusion

Predicting NIV failure can be difficult by routine initial clinical impression and diagnostic work up. This systematic review emphasizes the importance of using lung and diaphragm ultrasound, in particular the lung ultrasound score and diaphragm thickening fraction respectively, to accurately predict NIV failure, including the need for ICU-level of care, requiring invasive mechanical ventilation, and resulting in higher rates of mortality.

Effect of high-frequency oscillation on reduction of atelectasis in perioperative patients: a prospective randomized controlled study

BACKGROUND

Atelectasis affects approximately 90% of anaesthetized patients, with laparoscopic surgery and pneumoperitoneum reported to exacerbate this condition. High-frequency oscillation therapy applies continuous positive pressure pulses to oscillate the airway, creating a pressure difference in small airways obstructed by secretions. This process helps reduce peak airway pressure, open small airways, and decrease atelectasis incidence, while also facilitating respiratory tract clearance. This study examines the efficacy of high-frequency oscillation on reduction of atelectasis in laparoscopic cholecystectomy (LC) patients under general anaesthesia, evaluated using lung ultrasound.

METHODS

Sixty-four patients undergoing laparoscopic cholecystectomy were randomly divided into a control group and a high-frequency oscillation (HFO) group. Both groups underwent total intravenous anaesthesia under invasive arterial monitoring. The HFO group received a 10-minute continuous high-frequency oscillation therapy during surgery, while the control group received no intervention. Lung ultrasound evaluations were performed three times: five minutes post-intubation (T1), at the end of the surgery (T2), and before leaving the Post-Anaesthesia Care Unit (PACU; T3). Blood gas analysis was performed twice: prior to induction with no oxygen supply and before PACU discharge (oxygen supply off).

RESULTS

The HFO group displayed a significantly lower incidence of atelectasis at T3 (57.5% vs. 90.3%, OR 6.88, 95%CI (1.74 to 27.24)) compared to the control group. Moreover, the HFO group's PaO2 levels remained consistent with baseline levels before PACU discharge, unlike the control group. Although there was no significant difference in LUS scores between the groups at T1 (8.56 ± 0.15 vs. 8.19 ± 0.18, p = 0.1090), the HFO group had considerably lower scores at T2 (13.41 ± 0.17 vs.7.59 ± 0.17, p < 0.01) and T3 (13.72 ± 0.14 vs.7.25 ± 0.21, p < 0.01).

CONCLUSION

Our study indicates that high-frequency oscillation effectively reduces atelectasis in patients undergoing laparoscopic cholecystectomy. Additionally, it can mitigate the decline in oxygen partial pressure associated with atelectasis.