Recruitment Maneuver to Reduce Postoperative Pulmonary Complications after Laparoscopic Abdominal Surgery: A Systematic Review and Meta-Analysis

Effects of Different Extubation Strategies on Atelectasis in Older Adults after Major Abdominal Surgery: A Prospective Randomized Controlled Trial

BACKGROUND

Older patients are particularly vulnerable to age-related respiratory changes. This prospective randomized controlled trial studied the effects of high and low fractions of inspired oxygen (FiO2) with the recruitment maneuver (RM) during extubation on lung atelectasis postoperatively in older patients undergoing major abdominal surgery.

METHODS

We randomized a total of 126 patients aged >60 years who underwent both elective and emergency major abdominal surgeries and met the inclusion criteria into three groups (H, HR, and LR) using computer-generated block randomization. Group H received high FiO2 (1), Group HR received high FiO2 (1) with RM followed by a positive end-expiratory pressure of 5 cm H2O, and Group LR received low FiO2 (0.4) with RM followed by a positive end-expiratory pressure of 5 cm H2O 10 minutes before extubation. Oxygenation and atelectasis were measured using the arterial partial pressure of oxygen (PaO2)/FiO2 ratios and lung ultrasound score. Postoperative pulmonary complications were recorded up to 24 hours postoperatively.

RESULTS

The mean PaO2/FiO2 at 30 minutes post-extubation was significantly higher in Groups LR and HR compared to that in Group H (390.71±29.55, 381.97±24.97, and 355.37±31.70; p<0.001). In the immediate postoperative period, the median lung ultrasound score was higher in Group H than that in Groups LR and HR (6 [5-7], 3 [3-5], and 3.5 [2.25-4.75]; p<0.001). The incidence of oxygen desaturation and oxygen requirements was higher in Group H during the postoperative period.

CONCLUSION

The RM before extubation is beneficial in reducing atelectasis and postoperative pulmonary complications, irrespective of the FiO2 concentration used in older adults undergoing major abdominal surgeries. (Trail registration number: Reference No. CTRI/2022/04/042115; date of CTRI registration 25/02/2022; and date of enrolment of the first research participant 05/05/2022).

Individualized PEEP guided by EIT in patients undergoing general anesthesia: A systematic review and meta-analysis

BACKGROUND

The determination of optimal positive end-expiratory pressure (PEEP) values in patients undergoing general anesthesia remains controversial. Electrical impedance tomography (EIT) directed individualized PEEP has emerged as a novel approach to PEEP setting and has garnered increasing attention. This meta-analysis aims to systematically assess the effect of EIT-guided PEEP setting compared to traditional fixed PEEP values or other PEEP titration strategies in patients undergoing general anesthesia.

METHODS

A comprehensive search of electronic databases, including PubMed, Web of Science, EMBASE, and the Cochrane Library, was conducted from inception to January 2023, with no language restrictions. The search terms used were "EIT"and "PEEP" with their corresponding free words. Two researchers independently conducted literature screening, data extraction, and quality evaluation. The primary outcomes of interest were oxygenation index (OI), lung compliance, and number of postoperative pulmonary complications (PPCs). The secondary outcomes included mean arterial blood pressure (MAP) and number of vasoactive drug injections. RevMan 5.3 software was used to analyze the data and draw the forest plot, and Stata 14.2 software was used to conduct sensitivity analysis to assess the stability of the results.

RESULTS

5 studies involving 272 participants were included in this meta-analysis. Our findings suggest that EIT-guided individualized PEEP setting is superior to traditional fixed PEEP values and other individualized PEEP titration methods in terms of intraoperative OI(OR = 95.73, 95%CI: (49.10, 142.37); P < 0.0001) and lung compliance(OR = 7.69, 95%CI: (5.55, 9.83); P < 0.00001), without affecting intraoperative hemodynamic parameters such as MAP(OR = 2.07, 95%CI: (-1.00, 5.13); P = 0.19) and the number of intravenous vasoactive drugs(OR = 1.22, 95%CI: (0.68, 2.21); P = 0.51) or increasing the incidence of postoperative PPCs(OR = 0.87, 95%CI: (0.41, 1.82); P = 0.71).

CONCLUSIONS

Our meta-analysis suggests potential benefits of EIT-guided individualized PEEP setting in improving intraoperative oxygenation and lung compliance in patients undergoing general anesthesia. However, further research is needed to establish conclusive evidence, and caution should be exercised in interpreting these findings as the current literature remains inconclusive regarding the impact on intraoperative hemodynamics and postoperative complications.

Restoration of Pulmonary Compliance after Laparoscopic Gynecologic Surgery Using a Recruitment Maneuver

BACKGROUND/OBJECTIVES

This study aimed to investigate the hypothesis that an alveolar recruitment maneuver can restore lung compliance to initial values after laparoscopic gynecological surgery.

METHODS

A total of 31 patients who underwent laparoscopic gynecological surgery were enrolled. Protective mechanical ventilation was applied, and the radial artery was catheterized in all patients. An alveolar recruitment maneuver (incremental and decremental positive end-expiratory pressure) was applied ten minutes after the release of pneumoperitoneum. The respiratory mechanics and blood gas results were recorded at eight different time points: after induction of anesthesia (T1), in the lithotomy position (T2), in the Trendelenburg position (T3), 10 and 90 min after insufflation of carbon dioxide (T4 and T5), in the supine position (T6), after desufflation (T7), and 10 min after an alveolar recruitment maneuver at the end of surgery (T8).

RESULTS

Pneumoperitoneum and the Trendelenburg position caused a decline of 15 units in compliance (T7 vs. T1; p < 0.05) compared to baseline. After the alveolar recruitment maneuver, compliance increased by 17.5% compared with the mean value of compliance at time T1 (T8 vs. T1; p < 0.05). The recruitment maneuver had favorable results in patients with low initial compliance (41.5 mL/cmH2O, IQR: 9.75 mL/cmH2O), high Body Mass Index 30.32 kg/m2 (IQR: 1.05 kg/m2), and high initial plateau airway pressure (16.5 cmH2O, IQR: 0.75 cmH2O).

CONCLUSIONS

Lung compliance does not return to initial values after performing laparoscopic gynecological procedures. However, after the release of pneumoperitoneum, an alveolar recruitment maneuver is beneficial as it improves compliance and gas exchange.

The Effect of Recruitment Maneuver on Static Lung Compliance in Patients Undergoing General Anesthesia for Laparoscopic Cholecystectomy: A Single-Centre Prospective Clinical Intervention Study

Background and Objectives: The aim of this study was to examine whether the use of an alveolar recruitment maneuver (RM) leads to a significant increase in static lung compliance (Cstat) and an improvement in gas exchange in patients undergoing laparoscopic cholecystectomy. Material and Methods: A clinical prospective intervention study was conducted. Patients were divided into two groups according to their body mass index (BMI): normal-weight (group I) and pre-obese and obese grade I (group II). Lung mechanics were monitored (Cstat, dynamic compliance-Cdin, peak pressure-Ppeak, plateau pressure-Pplat, driving pressure-DP) alongside gas exchange, and hemodynamic changes (heart rate-HR, mean arterial pressure-MAP) at six time points: T1 (induction of anesthesia), T2 (formation of pneumoperitoneum), T3 (RM with a PEEP of 5 cm H2O), T4 (RM with a PEEP of 7 cm H2O), T5 (desufflation), and T6 (RM at the end). The RM was performed by increasing the peak pressure by +5 cm of H2O at an equal inspiration-to-expiration ratio (I/E = 1:1) and applying a PEEP of 5 and 7 cm of H2O. Results: Out of 96 patients, 33 belonged to group I and 63 to group II. An increase in Cstat values occurred after all three RMs. At each time point, the Cstat value was measured higher in group I than in group II. A higher increase in Cstat was observed in group II after the second and third RM. Cstat values were higher at the end of the surgical procedure compared to values after the induction of anesthesia. The RM led to a significant increase in PaO2 in both groups without changes in HR or MAP. Conclusions: During laparoscopic cholecystectomy, the application of RM leads to a significant increase in Cstat and an improvement in gas exchange. The prevention of atelectasis during anesthesia should be initiated immediately after the induction of anesthesia, using protective mechanical ventilation and RM.

Pulmonary Recruitment Prior to Intraoperative Multiple Pulmonary Ground-Glass Nodule Localization Increases the Localization Accuracy-A Retrospective Study

The standard treatment for early-stage lung cancer is complete tumor excision by limited resection of the lung. Preoperative localization is used before video-assisted thoracoscopic surgery (VATS) to improve the accuracy of pulmonary nodule excision. However, lung atelectasis and hypoxia resulting from controlling apnea during the localization procedure may affect the localization accuracy. Pre-procedural pulmonary recruitment may improve the respiratory mechanics and oxygenation during localization. In this study, we investigated the potential benefits of pre-localization pulmonary recruitment prior to pulmonary ground-glass nodule localization in a hybrid operating room. We hypothesized that pre-localization pulmonary recruitment would increase the localization accuracy, improve oxygenation, and prevent the need for re-inflation during the localization procedure. We retrospectively enrolled patients with multiple pulmonary nodule localizations before surgical intervention in our hybrid operating room. We compared the localization accuracy between patients who had undergone pre-procedure pulmonary recruitment and patients who had not. Saturation, re-inflation rate, apnea time, procedure-related pneumothorax, and procedure time were also recorded as secondary outcomes. The patients who had undergone pre-procedure recruitment had better saturation, shorter procedure time, and higher localization accuracy. The pre-procedure pulmonary recruitment maneuver was effective in increasing regional lung ventilation, leading to improved oxygenation and localization accuracy.

Effect of Intraoperative Lung Recruitment and Transversus Abdominis Plane Block in Laparoscopic Bariatric Surgery on Postoperative Lung Functions: A Randomized Controlled Study

Background

Morbid obesity may cause a restrictive condition. General anesthesia (GA) and supine posture both decrease lung capacity and functional residual capacity (FRC), altering the ventilation/perfusion ratio and raising the pulmonary shunt.

Objectives

To evaluate the impact of recruitment maneuver (RM) and transversus abdominis plane (TAP) block performed during laparoscopic bariatric surgery on spirometry, oxygenation, opioid requirements, and pain score assessed after surgery.

Methods

This pilot prospective randomized controlled study included 80 patients scheduled for elective laparoscopic bariatric surgeries (e.g., laparoscopic sleeve gastrectomy and laparoscopic gastric bypass) under GA. Patients were divided into four equal groups. All patients received a standardized postoperative analgesia regimen. Group I (control group), group II received TAP block after intubation and before surgical incision, group III received RM after intubation and after pneumoperitoneal insufflation, and group IV received RM after intubation and after pneumoperitoneal exsufflation and TAP block after intubation and before surgical incision.

Results

Forced vital capacity (FVC) and forced expiratory volume (FEV1) were significantly higher after group IV operation than in other groups. Intraoperative PaO2 and PaO2/FiO2 were significantly higher in groups III and IV compared to other groups. The numerical rating scale (NRS) at 1, 2, 4, 6, and 12h was significantly decreased in groups II and IV compared to other groups. Morphine consumption was significantly lower in groups II and IV compared to other groups.

Conclusions

TAP block combined with RM had better postoperative pulmonary function tests. Intraoperative oxygenation was higher in RM.

Individualized positive end-expiratory pressure guided by respiratory mechanics during anesthesia for the prevention of postoperative pulmonary complications: a systematic review and meta-analysis

The optimization of positive end-expiratory pressure (PEEP) according to respiratory mechanics [driving pressure or respiratory system compliance (Crs)] is a simple and straightforward strategy. However, its validity to prevent postoperative pulmonary complications (PPCs) remains unclear. Here, we performed a meta-analysis to assess such efficacy. We searched PubMed, Embase, and the Cochrane Library to identify randomized controlled trials (RCTs) that compared personalized PEEP based on respiratory mechanics and constant PEEP to prevent PPCs in adults. The primary outcome was PPCs. Fourteen studies with 1105 patients were included. Compared with those who received constant PEEP, patients who received optimized PEEP exhibited a significant reduction in the incidence of PPCs (RR = 0.54, 95% CI 0.42 to 0.69). The results of commonly happened PPCs (pulmonary infections, hypoxemia, and atelectasis but not pleural effusion) also supported individualized PEEP group. Moreover, the application of PEEP based on respiratory mechanics improved intraoperative respiratory mechanics (driving pressure and Crs) and oxygenation. The PEEP titration method based on respiratory mechanics seems to work positively for lung protection in surgical patients undergoing general anesthesia.

Lung mechanics during video-assisted abdominal surgery in Trendelenburg position: a cross-sectional propensity-matched comparison between classic laparoscopy and robotic-assisted surgery

BACKGROUND

Video-assisted surgery has become an increasingly used surgical technique in patients undergoing major thoracic and abdominal surgery and is associated with significant perioperative respiratory and cardiovascular changes. The aim of this study was to investigate the effect of intraoperative pneumoperitoneum during video-assisted surgery on respiratory physiology in patients undergoing robotic-assisted surgery compared to patients undergoing classic laparoscopy in Trendelenburg position.

METHODS

Twenty-five patients undergoing robotic-assisted surgery (RAS) were compared with twenty patients undergoing classic laparoscopy (LAS). Intraoperative ventilatory parameters (lung compliance and plateau airway pressure) were recorded at five specific timepoints: after induction of anesthesia, after carbon dioxide (CO₂) insufflation, one-hour, and two-hours into surgery and at the end of surgery. At the same time, arterial and end-tidal CO₂ values were noted and arterial to end-tidal CO₂ gradient was calculated.

RESULTS

We observed a statistically significant difference in plateau pressure between RAS and LAS at one-hour (26.2 ± 4.5 cmH₂O vs. 20.2 ± 3.5 cmH₂O, p = 0.05) and two-hour intervals (25.2 ± 5.7 cmH₂O vs. 17.9 ± 3.1 cmH₂O, p = 0.01) during surgery and at the end of surgery (19.9 ± 5.0 cmH₂O vs. 17.0 ± 2.7 cmH₂O, p = 0.02). Significant changes in lung compliance were also observed between groups at one-hour (28.2 ± 8.5 mL/cmH₂O vs. 40.5 ± 13.9 mL/cmH₂O, p = 0.01) and two-hour intervals (26.2 ± 7.8 mL/cmH₂O vs. 54.6 ± 16.9 mL/cmH₂O, p = 0.01) and at the end of surgery (36.3 ± 9.9 mL/cmH₂O vs. 58.2 ± 21.3 mL/cmH₂O, p = 0.01). At the end of surgery, plateau pressures remained higher than preoperative values in both groups, but lung compliance remained significantly lower than preoperative values only in patients undergoing RAS with a mean 24% change compared to 1.7% change in the LAS group (p = 0.01). We also noted a more significant arterial to end-tidal CO₂ gradient in the RAS group compared to LAS group at one-hour (12.9 ± 4.5 mmHg vs. 7.4 ± 4.4 mmHg, p = 0.02) and two-hours interval (15.2 ± 4.5 mmHg vs. 7.7 ± 4.9 mmHg, p = 0.02), as well as at the end of surgery (11.0 ± 6.6 mmHg vs. 7.0 ± 4.6 mmHg, p = 0.03).

CONCLUSION

Video-assisted surgery is associated with significant changes in lung mechanics after induction of pneumoperitoneum. The observed changes are more severe and longer-lasting in patients undergoing robotic-assisted surgery compared to classic laparoscopy.