Haemodynamic changes in patients with cardiovascular diseases under low-dose spinal anaesthesia during anorectal surgery assessed by impedance cardiography in lithotomy or jack-knife position

Abstract

Background and Goal of Study: The prone position for anorectal surgery is required to provide better exposure but can cause a reduction of cardiac output (CO) and cardiac index (CI)[1]. The aim of this study was to compare changes of haemodynamic parameters assessed by impedance cardiography of patients with cardiovascular diseases (ASA class 3) under selective spinal anaesthesia during anorectal surgery in lithotomy or jack-knife position. Materials and methods: approved by local Ethics Committee, the prospective observational study included 48 adult patients with co-morbidities (ASA class 3) admitted for elective anorectal surgery, randomly assigned to be performed in lithotomy (groupL, n=24) or jack-knife position (groupJ, n=24). Af ter arrival to operating room the standard and impedance cardiography monitoring was started and the following variables were recorded: CO, CI, systemic vascular resistance (SVR), systolic index (SI), measured at times of arrival to OR, placement for, start and end of surgery, placement to bed. Selective spinal block was made with 4mg of 0.5% hyperbaric bupivacaine and 10μg of Fentanyl. Comparison was based on haemodynamic changes between and inside groups over time. Results and discussion: Data are presented as mean±SD, *p<0.05 considered as statistically significant group J vs group L: Variable Group Baseline OR Laid for surgery Start of surgery End of surgery Placed to bed CO (l/min) L 6.1±1.4 6.8±1.4 6.4±1.5 6.2±1.5 5.6±1.0 CO (l/min) J 6.2±1.5 3.1±0.9* 3.0±0.8* 3.1±0.7* 5.5±1.0 CI (l/min/m2) L 3.2±0.7 3.4±0.5 3.3±0.6 3.3±0.7 3.0±0.6 CI (l/min/m2) J 3.3±0.6 1.8±0.6* 1.7±0.4* 1.7±0.4* 3.1±0.4 SI (ml/m2) L 42±11 46±8 47±9 47±12 42±9 SI (ml/m2) J 46±10 25±9* 23±7* 25±8* 39±8 SVR (dynes/sec/cm-5) L 1686 ±594 1511 ±639 1463 ±622 1465 ±637 1552 ±584 SVR (dynes/sec/cm-5) J 1683 ±732 2698 ±1061* 2821 ±1296* 2608 ±900* 1701 ±584 [Haemodynamic changes] Changes of all hemodynamic variables ov