Near-infrared spectroscopy for assessing microcirculation during laparoscopic gynaecological surgery under combined spinal-general anaesthesia or general anaesthesia alone: a randomised controlled trial.

While pneumoperitoneum causes negative macrohaemodynamic effects, much less is known about microcirculatory effects of different anaesthetic techniques and laparoscopy. Therefore, we aimed to explore microcirculatory effects of combined spinal-general anaesthesia and laparoscopy, as measured by near-infrared spectroscopy over forearm and calf muscles utilising a 3-min ischemic challenge. Patients (n = 102) undergoing elective laparoscopic gynaecological surgery were randomised to receive general anaesthesia alone or in combination with high-dose or low-dose spinal analgesia (levobupivacaine 7.5 mg or 3.75 mg, respectively, plus sufentanil 2.5 μg). Primary outcomes were near-infrared spectroscopy derived parameters before general anaesthesia induction, 5 min after tracheal intubation, and 15 min after pneumoperitoneum commencement. General anaesthesia resulted in impaired post-ischaemic recovery rate in the forearm (p < 0.001, within all groups), which improved during laparoscopy. For the calf, before general anaesthesia induction, high and low dose spinal analgesia significantly slowed the post-ischaemic recovery compared to control (34 ± 16% min-1 and 36 ± 13% min-1 vs. 52 ± 27% min-1, respectively; p = 0.002 and p = 0.006). General anaesthesia abolished differences between the groups (24 ± 14% min-1 and 25 ± 12% min-1 vs. 27 ± 18% min-1), while during laparoscopy high-dose spinal analgesia further reduced the post-ischaemic recovery compared to low-dose spinal and control groups (p = 0.023 and p = 0.040, respectively). During gynaecological laparoscopy patients show impaired calf but maintain forearm microcirculatory function, regardless of the anaesthetic technique. Reduction in post-ischaemic recovery with high-dose spinal analgesia is explained by its sympatholytic effects: number of perfused capillaries is increased, leading to a haemodynamically more favourable state. Blood pressure is positively correlated with the post-ischaemic recovery rate in vascular beds not affected by spinal analgesia.