Challenges for anaesthesia for robotic-assisted surgery in the elderly

Abstract

Steep and reverse Trendelenburg positions are often used in robotic-assisted surgery (RAS) to improve surgical access. The elderly are particularly vulnerable to the cardiovascular effect of the combination of pneumoperitoneum and these extreme positions. Falls in both cardiac output (CO) and mean arterial pressure (MAP) caused by pneumoperitoneum are enhanced in reverse Trendelenburg. Hypotension with dangerous cerebral and myocardial hypoperfusion may occur. Caution should be exercised in patients with low cardiac reserve and the degree of peri-operative risk should dictate the level of haemodynamic monitoring employed. The effects of pneumoperitoneum on CO are less pronounced in the standard Trendelenburg position due to gravity, but head-down combined with pneumoperitoneum can increase both MAP and systemic cardiovascular resistance. However, in patients with impaired myocardial contractility, the head-down position may lead to cardiac failure. In addition, the adverse respiratory effects of pneumoperitoneum, which include reduction of pulmonary compliance and functional residual capacity, may be exacerbated by steep Trendelenburg. At the same time, hypercarbia resulting from CO2 insufflation can lead to an increase in stasis of brain blood flow and intracranial pressure with possible repercussions on cognitive functions in the elderly. Another problem is the increase in intra-ocular pressure during steep Trendelenburg, and injury to the optic nerve has been reported after robot-assisted prostatectomy. Finally, strategies to use the lowest possible pneumoperitoneum pressure are considered to reduce possible complications. Moreover, the extreme positions should be limited only to the time strictly necessary for surgery and should be avoided in high-risk patients.