Obesity is associated with decreased lung compliance and hypercapnia during robotic assisted surgery

Dana Rodica Tomescu,Mihai Popescu,Nicolae Bacalbașa,Șerban Bubenek-Turconi,Simona Olimpia Dima

doi:10.1007/s10877-016-9831-y

Abstract

Robotic assisted surgery (RAS) represents a great challenge for anesthesiology due to the increased intraabdomial pressures required for surgical optimal approach. The changes in lung physiology are difficult to predict and require fast decision making in order to prevent altered gas exchange. The aim of this study was to document the combined effect of patient physical status, medical history and intraoperative position during RAS on lung physiology and to determine perioperative risk factors for hypercapnia. We prospectively analyzed 62 patients who underwent elective RAS. Age, co-morbidities and body mass index (BMI) were recorded before surgery. Ventilatory parameters and arterial blood gas analysis were determined before induction of anesthesia, after tracheal intubation and on an hourly basis until the end of surgery. In RAS, the induction of pneumoperitoneum was associated with a significant decrease in lung compliance from a mean of 42.5–26.7 ml cm H2O−1 (p = 0.001) and an increase in plateau pressure from a mean of 16.1 mmHg to a mean of 23.6 mmHg (p = 0.001). Obesity, demonstrated by a BMI over 30, significantly correlates with a decrease in lung compliance after induction of anesthesia (p = 0.001). A significant higher increase in arterial CO2 tension was registered in patients undergoing RAS in steep Trendelenburg position (p = 0.05), but no significant changes in end-tidal CO2 were recorded. A higher arterial to end-tidal CO2 tension gradient was observed in patients with a BMI > 30 (p < 0.001). In conclusion, patients’ physical status, especially obesity, represents the main risk factor for decreased lung compliance during RAS and patient positioning in either Trendelenburg or steep Trendelenburg during surgery has limited effects on respiratory physiology.

Highlights

The revolution introduced in the field of general surgery by performing laparoscopic procedures is tremendous
We sought to determine a predictive model for patients prone to develop hypercapnia in the intraoperative period due to CO2 pneumoperitoneum and to establish the correlation between end-tidal CO2 (EtCO2) and arterial CO2 pressure (PaCO2) in this setting
Our data suggest that there are no differences in Pplat, C or MV in patients undergoing Robotic assisted surgery (RAS) in regard to T or steep Trendelenburg (sT) positioning

Summary

Introduction

The revolution introduced in the field of general surgery by performing laparoscopic procedures is tremendous. Robotic assisted surgery (RAS) represents the latest innovation in minimally invasive surgery and its use has became widely spread in all subspecialties of general abdominal surgery including gynecologic procedures, colorectal surgery, gastric surgery and hepatobiliary surgery [1]. Robotic technologies allow the surgeon to have a three-dimensional view of the operating field, an increased instrumental degree of freedom and surgeon motion filtration [5]. In order to facilitate surgical movement, the patient is placed in either Trendelenburg (T) or steep Trendelenburg (sT) position for the duration of surgery, and this, combined with carbon dioxide (CO2) induced pneumoperitoneum is likely to cause significant changes in respiratory physiology. The large amounts of gas insufflated are absorbed via the peritoneal surface and lead to hypercapnia and respiratory acidosis if the CO2 cannot be excreted by increased minute ventilation

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