Jurgita Borodičienė, Jūratė Gudaitytė, Andrius Macas
The aim of the study was to determine limit of baseline cardiac output assessed by impedance cardiography, which allows predicting development of adverse haemodynamic reactions influenced by patient’s position changes during anorectal surgery under spinal anaesthesia with low dose hyperbaric bupivacaine for ASA 3 patients with cardiovascular diseases.Methods: The prospective observational clinical study included 48 adult patients with co-morbidities (ASA class 3) admitted for elective anorectal surgery, randomly assigned to be performed in jack-knife position (group I, n=24) or lithotomy (group II, n=24). Three patients were excluded from the study because of insufficient level of sensory block and treatment with vasoactive drugs during anaesthesia. After arrival to operating room the standard and impedance cardiography monitoring was started and the following variables were recorded: heart rate, blood pressure, saturation, electrocardiography, cardiac output and index, systemic vascular resistance 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.Results: Heart rate, mean blood arterial pressure were comparable between groups and remained stable after changes of patient position (p>0.05). The reduction of cardiac output was statistically significant after placement into jackknife position: from baseline 6.2+/-1.5 to 3.1+/-0.9 after placement for and 3.0+/-0.8-0.7 at the start and end of surgery (mean +/-SD l/ min). The difference of cardiac output between groups was 3.7 l/min and 3.3 l/min and 3.1 l/min, respectively (p<0.05). Cardiac output decreased below 3 l/min after patient’s placement into jack-knife position during surgery in case baseline cardiac output was less than 5.94 l/min.In conclusion, position of patient during surgery influences haemodynamic parameters and induces cardiac output reduction during minor anorectal surgery in jack-knife position under spinal anaesthesia with low dose hyperbaric bupivacaine for ASA 3 patients with cardiovascular diseases. The limit of baseline cardiac output leading to its significant reduction below 3.0 l/min after placement into jack-knife position for surgery is 5.94 l/min
Keyword(s): Spinal anaesthesia; minor anorectal surgery; jackknife position; cardiac output.
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