Neuroendocrine stress response and heart rate variability: A comparison of total intravenous versus balanced anesthesia

Attenuating intraoperative stress is a key factor in improving outcome. We compared neuroendocrine changes and heart rate variability (HRV) during balanced anesthesia (BAL) versus total IV anesthesia (TIVA). Forty-three patients randomly received either BAL (sevoflurane/remifentanil) or TIVA (propofol/ remifentanil). Depth of anesthesia was monitored by bispectral index. Stress hormones were measured at 7 time points (P1 = baseline; P2 = tracheal intubation; P3 = skin incision; P4 = maximum operative trauma; P5 = end of surgery; P6 = tracheal extubation; P7 = 15 min after tracheal extubation). HRV was analyzed by power spectrum analysis: very low frequency (VLF), low frequency (LF), high frequency (HF), LF/HF ratio, and total power (TP). LF/HF was higher in TIVA at P6 and TP was higher in TIVA at P3-7 (P3: 412.6 versus 94.2; P4: 266.7 versus 114.6; P5:290.3 versus 111.9; P6:1523.7 versus 658.1; P7: 1225.6 versus 342.6 ms(2)). BAL showed higher levels of epinephrine (P7:100.5 versus 54 pg/ mL), norepinephrine (P3: 221 versus 119.5; P4: 194 versus 130.5 pg/mL), adrenocorticotropic hormone (P2 10.5 versus 7.7; P5: 5.3 versus 3.6; P6:10.9 versus 5.3; P7: 20.5 versus 7.1 pg/mL) and cortisol (P7: 6.9 versus 3.9 mu g/dL). This indicates a higher sympathetic outflow using BAL versus TIVA during ear-nose-throat surgery.