DEPENDENCE OF THE PAIN SYNDROME INTENSITY AFTER LAPAROSCOPIC SURGERY ON THE RESIDUAL VOLUME OF WORKING GAS IN THE ABDOMINAL CAVITY
Authors: Parakhoniak R. L. 
Published: April 2022

Induction of pneumoperitoneum is a mandatory step in laparoscopic surgery in order to create a workspace for the surgeon. The cause of omalgia (pain in shoulder area) after such interventions is the accumulation of residual gas in the abdominal cavity.There are still no proven methods of quantitative assessment of the residual pneumoperitoneum. Thus, the patterns of relationship between the amount of residual gas and the intensity of pain syndrome have not been studied yet. Considering the fact that the residual gas exerts mechanical distention of anatomical structures and apparently causes local irritation in the peritoneum, it is necessary to develop preventive measures for omalgia which may involve not only the approaches to reduce the amount of residual gas but also the use of alternative gas sources, particularly argon. As inert gas argon possesses many positive qualities, it does not affect the peritoneum, and has no resorptive metabolic effects.
The goal of our research is to work out an X-ray planimetric method for determining the amount of residual gas after laparoscopic surgery and to assess the dependence of the pain intensity on both, the amount of residual gas and the type of working gas used.
Material and methods of research. Two experimental groups of patients with uncomplicated cholelithiasis were formed, and carboxyperitoneum and argonperitoneum were used to create the space during laparoscopic cholecystectomy. The groups of examined patients are equivalent by age and sex and are randomized for consecutive admission to the hospital. Both groups include patients who underwent surgery without the use of any drainage means. 24 hours after the operation, a chest plain radiography was performed in order to identify the area of gas crescent sign under the right hemidiaphragm using personally-developed original approach. The technique is based on the use of a mobile application to measure the area of complex geometric shapes. At the same time, the intensity of pain syndrome in the shoulder area was assessed in all the patients by means of NRS (Numeric Rating Scale) in combination with Rotterdam Elderly Pain Observation Scale (REPOS). The technique is aimed to objectify the subjective assessment of pain. Statistical software for Microsoft Excel 2010 was used for processing the study results and calculating Pearson’s correlation coefficient.
Results of research and their discussion. The obtained results revealed moderate correlation relationship between the area of gas crescent sign under the right hemidiaphragm and pain syndrome intensity. This relationship was confirmed both in the group with carboxyperitoneum and in the group with argon as the working gas. However, it was observed that the proportion of patients with postoperative omalgia in the group with argonoperitoneum is significantly lower. Thus, both hypotheses, concerning the role of mechanical factors in the development of omalgic syndrome and the significance of chemical local peritoneal irritation have been confirmed.
Conclusions:

The suggested method of radiological planimetry allows to obtaine the digital indicators suitable for statistical analysis which characterize the amount of residual gas after laparoscopic surgery.
The intensity of pain syndrome exhibits correlation with the amount of residual gas after the surgery.
The severity of omalgia depends primarily on the amount of residual gas. However, the incidence of omalgic syndrome with the use of carbon dioxide is higher than with argon use.