Abstract and Introduction
Abstract
Background: Increasing numbers of robotic hysterectomies (RH) are being performed. To provide ventilation (with pneumoperitoneum and steep Trendelenburg position) for these procedures, utilization of lung protective strategies with limiting airway pressures and tidal volumes is difficult. Little is known about the effects of intraoperative mechanical ventilation and high peak airway pressures on perioperative complications. We performed a retrospective review to determine whether patients undergoing RH had increased pulmonary complications compared to total abdominal hysterectomy (TAH).
Methods: We performed a single center retrospective review comparing the intraoperative, anesthetic, and immediate and 30-day postoperative course of patients undergoing RH to TAH, including intraoperative ventilatory parameters and respiratory complications. Patients undergoing TAH (201) from 2004 to 2006 were compared to RH (251) from 2009 to 2012. It was our hypothesis that patients undergoing RH would have increased incidence of postoperative pulmonary complications. A secondary hypothesis was that morbid obesity predicts pulmonary complications in patients undergoing RH. Complications were compared between groups using Fisher's exact test. To account for potential confounders, the primary analysis was performed for a subgroup of patients matched on the propensity for RH.
Results: A total of 351 RH and 201 TAH procedures are included. Higher inspiratory pressures were required in ventilation of the RH group (median [25th, 75th] 31 [26,36] cm H2O) than the TAH group (23 [19,27] cm H2O) (P < .001) at 30 minutes after incision. Peak inspiratory pressures at 30 minutes after incision for RH increased according to increasing body mass index group (P < .001). There were 163 RH and 163 TAH procedures included in the propensity matched analysis. From this analysis, there were no significant differences in cardiopulmonary complications between RH and TAH (0.6% vs 1.2%; odds ratio = 2.0, 95% confidence interval = 0.2–2.4; P = 1.00). Surgical site infection was significantly lower in the RH compared to TAH group (0.6% vs 8.6%; P < .001). Hospital length of stay was longer for those who underwent TAH versus RH (median [25th, 75th] 2 [2,3] vs 1 [0,2] days; P < .001).
Conclusions: There was no significant difference in perioperative complications in obese and morbidly obese women compared to nonobese undergoing RH. Patients undergoing RH had shorter hospital stays, fewer infectious complications, and no increase in overall complications compared to TAH. Higher ventilatory airway pressures (RH versus TAH and obese versus nonobese) did not result in an increase in cardiopulmonary or overall complications. We believe that peritoneal insufflation attenuates the effect of high airway pressures by raising intrapleural pressure and reducing the gradient across terminal bronchioles and alveoli. Thus, we propose that lung protective strategies for patients undergoing RH account for the markedly elevated intraperitoneal and intrapleural pressures, whereas transpulmonary airway pressures remain static. This reduced transpulmonary gradient attenuates the strain on lung tissue that would otherwise be imposed by ventilation at high pressures.
Introduction
There has been an increasing availability and utilization of minimally invasive surgical techniques (MIST). Laparoscopic hysterectomy was first developed in the 1960s. A robotic platform for gynecologic procedures was approved by the US Food and Drug Administration in 2005. Since this time, increasing numbers of minimally invasive hysterectomies have been performed. Between 2007 and 2010, robotic procedures increased from 0.5% to 9.5% of all hysterectomies performed, whereas laparoscopic hysterectomies increased from 24.5% to 30.5%.[1,2] By 2013, 191,000 robotic hysterectomies (RH) had been performed in the United States.[3] Recent studies have demonstrated a reduced hospital length of stay and lower intraoperative blood loss when MIST are compared with total abdominal hysterectomy (TAH).[1,4]
MIST hysterectomy requires utilization of pneumoperitoneum and steep Trendelenburg for visualization of the pelvis. RH frequently requires Trendelenburg positioning of >30[spacing ring above], and a patient must stay in a fixed position while the robot is docked. Although Trendelenburg position decreases pulmonary compliance and functional residual capacity[5,6] and can worsen arterial oxygenation, the addition of pneumoperitoneum accentuates respiratory compromise.[7] The respiratory consequences of robotic surgery include increased peak airway pressures, increased inspired-to-arterial oxygen gradient, increased arterial to end-tidal carbon dioxide gradient, and lower tidal volumes.[8] These conditions could potentially result in an increase in atelectasis and postoperative respiratory complications. Literature over the past 2 decades has indicated that mechanical ventilation with lower tidal volumes might be protective of the lung in certain clinical conditions.[9] Recent literature suggests that the magnitude tissue strain is the main determinant of mechanical lung injury. Transpulmonary pressure (airway pressure minus intrapleural pressure) is a measure of lung parenchymal stress. In the situation of RH, abdominal insufflation could potentially transmit pressures across the diaphragm to raise intrapleural pressures and result in reduced strain and injury of the lung.[10]
We performed a retrospective review to assess whether undergoing RH was associated with higher incidence of pulmonary complications compared with TAH.
Anesth Analg. 2018;126(1):127-133. © 2018 International Anesthesia Research Society
