: To investigate reliability of Bio-impedance Cardiometer parameters in comparison with basic non-invasive parameters for detection of haemodynamic changes during percutaneous nephrolithotomy (PNL) under spinal anesthesia.
: Forty patients were enrolled. Basal and 10-min interval parameters were recorded, included systolic blood pressure, mean arterial blood pressure, heart rate, O saturation and bio-impedance parameters. According to blood loss as measured by haemoglobin HB level, patients were divided into two groups; significant blood loss group > 20% from basal HB were compared with non-significant loss group.
: Significant blood loss included 14 (35%) patients while other group included 26 (65%) patients. No difference was detected in demographics, basic non-invasive and bio-impedance cardiometer parameters either at basal values or at minute-120. No difference was detected in recorded data per 10-min interval in both groups throughout procedure except for heart rate and systolic time ratio (STR). STR changes were noticed 20 minutes prior to HR changes (at 80 minutes and 100 min, respectively). Mean±SD of STR at minute-80 was higher in group of significant blood loss (0.44 ± 0.07 Vs 0.38 ± 0.05, P 0.018). HR started to be significantly higher at minute-100 (87.5 ± 13 Vs.78.6 ± 12, P 0.05).
: STR is a more reliable tool than MBP and HR for early detection of haemodynamic collapse in case of non-measurable bleeding during PNL. STR should be integrated as a routine monitoring tool during PNL.