Background and Goal of Study: We recently reported that pneumoperitoneum increased stroke volume variation (SVV), and upon release of the pneumoperitoneum, SVV decreased significantly [1]. We have asserted that SVV values must be estimated cautiously during pneumoperitoneum [1]. Plethysmographic variability index (PVI) is another dynamic index used to assess fluid responsiveness in patients, and the effect of pneumoperitoneum on PVI is still unclear [2, 3]. We therefore attempted to determine whether PVI and perfusion index (PI) change both before and after pneumoperitoneum in humans.
Materials and Methods: The 20 patients completing the study had an average (mean ± SD) age of 57 ± 15 years, body weight of 64 ± 18 kg, and height of 162 ± 10 cm. Male:female ratio and cholecystectomy:colectomy ratio were both 13:7. After induction of general anaesthesia, the patient’s lungs were mechanically ventilated. Immediately before pneumoperitoneum, baseline registrations of variables were obtained (baseline I), and these variables were measured every min for 5 min after pneumoperitoneum started and immediately before pneumoperitoneum was released. Baseline II registration of variables was then obtained, and these variables were obtained every min for 5 min after release of pneumoperitoneum.
Results and Discussion: Compared with baseline I values, after pneumoperitoneum started there was significant increase in SVV at the 2- to 5-min time points. There was significant decrease in PI at the 1- to 5-min time points, and no change in other values including PVI (Figs. 1, 2). Compared with baseline II values, after release of pneumoperitoneum there was significant increase in PI at the 1- to 5-min time points. There were significant decreases in PVI at the 4- to 5-min time points, and SVV at the 1- to 5-min time points (Figs. 3, 4). Some studies showed that pneumoperitoneum decreased PI and increased PVI [2, 3], but our results were not entirely similar to their results. We showed new information indicating that PI increased and PVI decreased upon release of the pneumoperitoneum.
Conclusions: PI and PVI values must be estimated cautiously during and after pneumoperitoneum.
References:
1. Wajima Z, et al. J Anesth 2015;29:508-14
2. Liu F, et al. Biosci Trends 2015;9:129-33
3. Høiseth LØ, et al. Acta Anaesthesiol Scand 2012;56:777-86

Does pneumoperitoneum affect perfusion index and plethysmographic variability index in humans?