Rationale and study design for an Individualized PeriopeRative Open lung VEntilatory approach in Emergency Abdominal Laparotomy/scopy: study protocol for a prospective international randomized controlled trial

BACKGROUND

Postoperative pulmonary complications (PPC) are the most frequent postoperative complications, with an estimated prevalence in elective surgery ranging from 20% in observational cohort studies to 40% in randomized clinical trials. However, the prevalence of PPCs in patients undergoing emergency abdominal surgery is not well defined. Lung-protective ventilation aims to minimize ventilator-induced lung injury and reduce PPCs. The open lung approach (OLA), which combines recruitment manoeuvres (RM) and positive end-expiratory pressure (PEEP) titration, aims to minimize areas of atelectasis and the development of PPCs; however, there is no conclusive evidence in the literature that OLA can prevent PPCs. The purpose of this study is to compare an individualized perioperative OLA with conventional standardized lung-protective ventilation in patients undergoing emergency abdominal surgery with clinical signs of intraoperative lung collapse.

METHODS

Randomized international clinical trial to compare an individualized perioperative OLA (RM plus individualized PEEP and individualized postoperative respiratory support) with conventional lung-protective ventilation (standard PEEP of 5 cmH2O and conventional postoperative oxygen therapy) in patients undergoing emergency abdominal surgery with clinical signs of lung collapse. Patients will be randomised to open-label parallel groups. The primary outcome is any severe PPC during the first 7 postoperative days, including: acute respiratory failure, pneumothorax, weaning failure, acute respiratory distress syndrome, and pulmonary infection. The estimated sample size is 732 patients (366 per group). The final sample size will be readjusted during the interim analysis.

DISCUSSION

The Individualized Perioperative Open-lung Ventilatory Strategy in emergency abdominal laparotomy (iPROVE-EAL) is the first multicentre, randomized, controlled trial to investigate whether an individualized perioperative approach prevents PPCs in patients undergoing emergency surgery.

Use of thoracic fluid content for prediction of fluid balance and postoperative pulmonary complications after major abdominal surgery: an observational study

BACKGROUND AND OBJECTIVES

The harmful effects of excess fluids frequently manifest in the lungs. Thoracic fluid content (TFC) is a variable provided by the STARLINGTM bioreactance monitor, which represents the total volume of fluid in the chest. The objective is to analyse the association between the variation in TFC values (TFCd0%) at 24 h postoperatively, postoperative fluid balance, and postoperative pulmonary complications.

MATERIAL AND METHODS

Prospective and analytical observational study. Patients scheduled for major abdominal surgery at a tertiary teaching hospital were included. They were monitored during the intervention and the first 24 postoperative hours with the monitor. STARLINGTM, measuring TFC and its variation in different stages of the perioperative period. Serial lung ultrasounds were performed and postoperative pulmonary complications were recorded. Logistic regression was performed to predict the occurrence of atelectasis and pulmonary congestion. The Pearson correlation coefficient was calculated to verify the association between TFC and fluid balance.

RESULTS

50 patients were analyzed. TFCd0% measured on the morning of the first postoperative day increased by a median of 27.1% [IQR: 20.3-37.5] and was correlated at r = 0.44 with the postoperative balance of 677 ml [IQR: 125.5-1,412]. Increased TFC was related to a higher risk of atelectasis (OR = 1.24) and pulmonary congestion (OR = 1.3).

CONCLUSIONS

TFCd0% measured 24 h after surgery presents a moderate correlation with postoperative fluid balance. Its increase is a risk factor for the appearance of postoperative pulmonary complications.