Esophageal Pressure Versus Gas Exchange to Set PEEP During Intraoperative Ventilation.

BACKGROUND: Pneumoperitoneum and Trendelenburg position affect respiratory system mechanics and oxygenation during elective pelvic robotic surgery. The primary aim of this randomized pilot study was to compare the effects of a conventional low tidal volume ventilation with PEEP guided by gas exchange (VGas-guided) versus low tidal volume ventilation tailoring PEEP according to esophageal pressure (VPes-guided) on oxygenation and respiratory mechanics during elective pelvic robotic surgery. METHODS: This study was conducted in a single-center tertiary hospital between September 2017 and January 2019. Forty-nine adult patients scheduled for elective pelvic robotic surgery were screened; 28 subjects completed the full analysis. Exclusion criteria were American Society of Anesthesiologists physical status ≥ 3, contraindications to nasogastric catheter placement, and pregnancy. After dedicated naso/orogastric catheter insertion, subjects were randomly assigned to VGas-guided ([Formula: see text] and PEEP set to achieve [Formula: see text] > 94%) or VPes-guided (PEEP tailored to equalize end-expiratory transpulmonary pressure). Oxygenation ([Formula: see text]/[Formula: see text]) was evaluated (1) at randomization, after pneumoperitoneum and Trendelenburg application; (2) at 60 min; (3) at 120 min following randomization; and (4) at end of surgery. Respiratory mechanics were assessed during the duration of the study. RESULTS: Compared to VGas-guided, oxygenation was higher with VPes-guided at 60 min (388 ± 90 vs 308 ± 95 mm Hg, P = .02), at 120 min after randomization (400 ± 90 vs 308 ± 81 mm Hg, P = .008), and at the end of surgery (402 ± 95 vs 312 ± 95 mm Hg, P = .009). Respiratory system elastance was lower with VPes-guided compared to VGas-guided at 20 min (24.2 ± 7.3 vs 33.4 ± 10.7 cm H2O/L, P = .001) and 60 min (24.1 ± 5.4 vs 31.9 ± 8.5 cm H2O/L, P = .006) from randomization. CONCLUSIONS: Oxygenation and respiratory system mechanics were improved when applying a ventilatory strategy tailoring PEEP to equalize expiratory transpulmonary pressure in subjects undergoing pelvic robotic surgery compared to a VGas-guided approach. (ClinicalTrials.gov registration NCT03153592).

Mechanical Ventilation Guided by Uncalibrated Esophageal Pressure May Be Potentially Harmful.

BACKGROUND: Esophageal balloon calibration was proposed in acute respiratory failure patients to improve esophageal pressure assessment. In a clinical setting characterized by a high variability of abdominal load and intrathoracic pressure (i.e., pelvic robotic surgery), the authors hypothesized that esophageal balloon calibration could improve esophageal pressure measurements. Accordingly, the authors assessed the impact of esophageal balloon calibration compared to conventional uncalibrated approach during pelvic robotic surgery. METHODS: In 30 adult patients, scheduled for elective pelvic robotic surgery, calibrated end-expiratory and end-inspiratory esophageal pressure, and the associated respiratory variations were obtained at baseline, after pneumoperitoneum-Trendelenburg application, and with positive end-expiratory pressure (PEEP) administration and compared to uncalibrated values measured at 4-ml filling volume, as per manufacturer recommendation. Data are expressed as median and [25th, 75th percentile]. RESULTS: Ninety calibrations were successfully performed. Chest wall elastance worsened with pneumoperitoneum-Trendelenburg and PEEP (19.0 [15.5, 24.6] and 16.7 [11.4, 21.7] cm H2O/l) compared to baseline (8.8 [6.3, 9.8] cm H2O/l; P < 0.0001 for both comparisons). End-expiratory and end-inspiratory calibrated esophageal pressure progressively increased from baseline (3.7 [2.2, 6.0] and 7.7 [5.9, 10.2] cm H2O) to pneumoperitoneum-Trendelenburg (6.2 [3.8, 10.2] and 16.1 [13.1, 20.6] cm H2O; P = 0.014 and P < 0.001) and PEEP (8.8 [7.7, 15.6] and 18.9 [16.3, 22.0] cm H2O; P < 0.0001 vs. baseline for both comparison; P < 0.001 and P = 0.002 vs. pneumoperitoneum-Trendelenburg) and, at each study step, they were persistently lower than uncalibrated esophageal pressure (P < 0.0001 for all comparisons). Overall, difference among uncalibrated and calibrated esophageal pressure was 5.1 [3.8, 8.4] cm H2O at end-expiration and 3.8 [3.0, 6.3] cm H2O at end-inspiration. Uncalibrated esophageal pressure swing was always lower than calibrated one (P < 0.0001 for all comparisons) with a difference of -1.0 [-1.8, -0.4] cm H2O. CONCLUSIONS: In a clinical setting with variable chest wall mechanics, uncalibrated measurements substantially overestimated absolute values and underestimated respiratory variations of esophageal pressure. Calibration could substantially improve mechanical ventilation guided by esophageal pressure.

Joint consensus on anesthesia in urologic and gynecologic robotic surgery: specific issues in management from a task force of the SIAARTI, SIGO, and SIU.

INTRODUCTION: Proper management of patients undergoing robotic-assisted urologic and gynecologic surgery must consider a series of peculiarities in the procedures for anesthesiology, critical care medicine, respiratory care, and pain management. Although the indications for robotic-assisted urogynecologic surgeries have increased in recent years, specific guidance documents are still lacking. EVIDENCE ACQUISITION: A multidisciplinary group including anesthesiologists, gynecologists, urologists, and a clinical epidemiologist systematically reviewed the relevant literature and provided a set of recommendations and unmet needs on peculiar aspects of anesthesia in this field. EVIDENCE SYNTHESIS: Nine core contents were identified, according to their requirements in urogynecologic robotic-assisted surgery: patient position, pneumoperitoneum and ventilation strategies, hemodynamic variations and fluid therapy, neuromuscular block, renal surgery and prevention of acute kidney injury, monitoring the Department of anesthesia, postoperative delirium and cognitive dysfunction, prevention of postoperative nausea and vomiting, and pain management in endometriosis. CONCLUSIONS: This consensus document provides guidance for the management of urologic and gynecologic patients scheduled for robotic-assisted surgery. Moreover, the identified unmet needs highlight the requirement for further prospective randomized studies.