Monitoring System during Enflurane Anesthesia Using Heart Rate Variability. |
Seong Wan Baik, Kyu Youn Jung, Soo Young Ye, Bong Hyo Han, Byeong Cheol Choi, Gye Rock Jeon |
1Department of Anesthesia and Pain Medicine, College of Medicine, Pusan National University, Pusan, Korea. 2Department of Interdisciplinary Program in Biomedical Engineering, Pusan National University, Pusan, Korea. 3Department of Biomedical Engineering, Choonhae College, Pusan, Korea. 4Department of Biomedical Engineering, College of Medicine, Pusan National University, Pusan, Korea. |
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Abstract |
BACKGROUND We performed spectral analysis and determined the 1/f noise of heart rate variability during enflurane anaesthesia in order to assess the effect of the activity of the autonomic nervous system. METHODS Data were acquired from 15 patients (ASA I-II) who received gynecological surgery under general anesthesia using enflurane, nitrous oxide and oxygen. We analyzed the spectral components of heart rate variability (HRV) according to the following five periods: 1) before premedication, 2) after induction, 3) during skin incision, 4) during recovery, and 5) after surgery. For each power spectrum the density and frequency components were identified as follows: (1) low frequency (LF) component (0.04-0.15 Hz) was associated with parasympathetic and sympathetic tone, and was affected by body temperature, the renin-angiotensin system, baroreceptor and vasomotor sympathetic modulation, (2) high frequency (HF) component (0.15-0.5 Hz) was mediated parasympathetic tone and reflected the mechanical influence of the ventilation. In addition the LF/HF ratio, which reflected cardiac sympathovagal balance was monitored. RESULTS The LF/HF ratio, which reflects the balance of the autonomic nervous system increased remarkably during skin incision and recovery. Also, the beta index, which is related to body activity decreased during skin incision and recovery. CONCLUSIONS Increased LF/HF was found to be caused by mechanical stimulation, which reflects autonomic nervous system balance, and the beta index was useful for the assessment of body activity. |
Key Words:
beta index; enflurane; heart rate variability; LF/HF |
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