Comparison of peri operative pulmonary outcomes in volume - controlled ventilation versus pressure - controlled ventilation in patients undergoing robot assisted urology surgery in trendelenburg position - A prospective randomised controlled trial

Robot assisted urology surgeries are not only minimally invasive, these are also associated with increased accuracy, precision, reduced intra-operative blood loss and shorter length of hospital stay as compared to open surgery.(1)  As a consequence, robot assisted surgeries are increasing worldwide. However, robot assisted surgery requires pneumoperitoneum and trendelenburg position (surgeries like robot assisted radical prostatectomy)  for optimal exposure. Pneumoperitoneum leads to an increased intra- abdominal pressure and cephalad shift of the diaphragm. Similarly, trendelenburg position restricts diaphragm excursion and thoracic expansion.(2)  These lead to decreased functional residual capacity, respiratory compliance, basal atelectasis and ventilation- perfusion mismatch.

There is literature available on the respiratory physiology, gas exchange, trans-pulmonary pressure and regional ventilation during robot assisted surgeries. Further, the effects of different levels of PEEP, recruitment manoeuvres and low tidal volume on gas exchange, pulmonary compliance and hemodynamics have also been evaluated.(3,4) The effect of ventilatory strategies like pressure controlled ventilation- volume guaranteed ( PCV-VG), PC- inverse ratio on oxygenation, gas exchange and post-operative pulmonary functions have also been compared.

The optimal ventilation strategy for robot assisted surgery is still controversial.We decided to compare the peri-operative pulmonary outcomes of pressure- controlled ventilation and volume- controlled ventilation in patients undergoing robot assisted urology surgery in Trendelenburg position. Lung Ultrasound Score is known well to correlate with peri-Operative Atelectasis [5]. For intra-operative pulmonary changes, we will be comparing the gas exchange and pulmonary mechanics between the two groups. As lung ultrasound score correlates well with the peri-operative atelectasis so we decided to assess the post-operative pulmonary outcomes by lung aeration score done in the immediate post-operative period and 24 hours later.

References

1. Yu H yin, Hevelone ND, Lipsitz SR, Kowalczyk KJ, Hu JC. Use, Costs and Comparative Effectiveness of Robotic Assisted, Laparoscopic and Open Urological Surgery. Journal of Urology [Internet]. 2012 Apr 1 [cited 2024 Oct 19];187(4):1392–9. Available from: https://doi.org/10.1016/j.juro.2011.11.089

2. Kaye AD, Vadivelu N, Ahuja N, Mitra S, Silasi D, Urman RD. Anaesthetic considerations in robotic-assisted gynecologic surgery. Ochsner J. 2013 Winter;13(4):517-24. PMID: 24358000; PMCID: PMC3865830.

3. Park JH, Park IK, Choi SH, Eum D, Kim MS. Volume-Controlled Versus Dual-Controlled Ventilation during Robot-Assisted Laparoscopic Prostatectomy with Steep Trendelenburg Position: A Randomised-Controlled Trial. J Clin Med. 2019 Nov 21;8(12):2032. doi: 10.3390/jcm8122032. PMID: 31766358; PMCID: PMC6947332.

4. Suh MK, Seong KW, Jung SH, Kim SS. The effect of pneumoperitoneum and Trendelenburg position on respiratory mechanics during pelviscopic surgery. Korean J Anesthesiol. 2010 Nov;59(5):329-34. doi: 10.4097/kjae.2010.59.5.329. Epub 2010 Nov 25. PMID: 21179295; PMCID: PMC2998653.

5 .Yu, Xin, et al. "Performance of lung ultrasound in detecting peri-operative atelectasis after general anesthesia." Ultrasound in medicine & biology 42.12 (2016): 2775-2784.