Evaluation of cardiac output by CO2 partial rebreathing technique in patients undergoing laparoscopic surgery under general anaesthesia compared to thoracic electric bioimpedance

Ruxandra Copotoiu, M. Chiorean, L. Azamfirei, Ioana Ghiţescu, Sanda-Maria Copotoiu

Universitatea de Medicină şi Farmacie Târgu Mureş, Disciplina Anestezie Terapie Intensivă; Clinica A.T.I. I, Spitalul Clinic Judeţean de Urgenţă Mureş

Abstract

Low-flow insufflation of CO2 into the abdominal cavity increases the surgical field during laparoscopic cholecystectomy with a negative impact on the hemodynamic parameters. Being a so-called low risk intervention, there is no need for invasive hemodynamic monitoring in cardiac patients from a cost-efficiency point of view. There is a need for non-invasive or minimally invasive devices.

Aim: To assess the hemodynamic parameters recorded by two different methods: noninvasive cardiac output (NICO) and thoracic electrical bioimpedance (TEB).

Material and method: 20 ASA I-II patients (8 male, 12 female) whose gallbladder was surgically removed by laparoscopic surgery were included in a randomised prospective study. Apart from the standard monitoring, we used thoracic electrical bioimpedance to asses in real time the cardiac index and the stroke index. The same parameters were assessed by CO2 partial reinhalation. The induction of general anaesthesia was performed by the i.v. route, while maintenance was balanced (inhalational; i.v. for analgesia). Data were analysed with GraphPadPrism 5.0.

Results: The values of CI measured by TEB were by 40% below to 16% above those measured by NICO. The scatter of the differences increased as the average increased. It means that the limits of agreement would be narrower for large CI. For the Pearson correlation r was 0.8795 (p < 0.0001). The Bland-Altman analysis yields a bias of 0.2800 (SD = 0.4538) and 95% limits of agreement of ‑0.60 and 1.16. The negative hemodynamic effects due to the CO2 pneumoperitoneum were short lived (6 to 9 minutes).

Conclusions: Although CO2 pneumoperitoneum does not have an impact on NICO readings, for small CI values, the limit of agreement is more than 30%. We cannot assess on the influence this difference has on the management of patients with impaired cardiac function.

Keywords: TEB, NICO, cardiac index, stroke index, laparoscopic cholecystectomy

Evaluarea monitorizării debitului cardiac prin reinhalare parţială de CO2 la pacienţii supuşi colecistectomiei laparoscopice în anestezie generală, prin comparaţie cu bioimpedanţa electrică transtoracică