impact of sitting or semi-setting position of patients during breast surgery on hemodynamic indexes

background: keeping the patient in a sitting or semi-sitting position for time-consuming oncoplastic breast surgery is a major challenge for anesthesiologists due to several considerations. this cohort study was conducted on two groups of patients undergoing breast surgery. methods: study participants were categorized into two groups: one group was composed of normotensive women (group a) and the other group comprised women with controlled hypertension (group b). after the induction of anesthesia in the supine position, the position was changed to sitting and the surgery was done in the sitting position. hemodynamic monitoring included ecg, heart rate, non-invasive blood pressure (nibp), invasive blood pressure (ibp), cardiac output (co), arterial o2 saturation (spo2), end-tidal co2 (etco2), and bispectral index (bis). the amount of administrated fluid and vasopressor was recorded for each patient. any episode of hemodynamic instability was recorded, too. results: hemodynamic variation occurred in both groups, but the changes were more significant in group b and the amount of fluid and vasopressor administration was more prominent in group b. changing the position caused no significant variation in bis, spo2, and etco2 in the two groups. conclusions: the sitting position can be safe for time-consuming oncoplastic breast surgery using adequate hemodynamic monitoring. hemodynamic changes are more significant in patients with controlled hypertension, and more medical interference is needed for these patients.