Anesthetic Management of Complete Tracheal Transection using Percutaneous Cardiopulmonary Support System : A case report / 대한마취과학회지

Patients with complete tracheal transection present a considerable challenge to the anesthesiologist. A 38 year-old woman with complete tracheal transection above the aortic arch level due to blunt trauma was taken to the operating room for an attempt at tracheal repair. Anesthetic management was focused on the maintenance of the airway and adequate ventilation. Primary repair of the trachea was carried out under ventilation support via percutaneous cardiopulmonary support system. Until the disrupted trachea was exposed on the surgical field, ventilation was performed using a laryngeal mask. We discuss the anesthetic management strategies and the alternative mode of ventilation.

Assessment of Autonomic Response before and after Total Spinal Anesthesia in Rats: Power Spectral Analysis / 대한마취과학회지

BACKGROUND: Total spinal anesthesia (TSA) after injections of local anesthetics into the intrathecal space during epidural anesthesia is not rare. TSA anesthetizes cranial nerves and peripheral nerves, causes specific circulatory disturbances related to autonomic imbalance. Spectral analysis of heart rate variability (HRV) and blood pressure variability (BPV) provide a dynamic assessment of sympathetic and parasympathetic tone. Cross-spectral analysis has been used to emphasize this dynamic baroreflex control of HR as a frequency-dependent phenomenon and allows an assessment of baroreflex function. To examine the effects of TSA on the autonomic nervous system, we used spectral and cross-spectral analytic METHODS. METHODS: We investigated 14 rats before and after TSA. Power spectral densities of blood pressure (BP) and heart rate (HR) were estimated by fast Fourier transform. To evaluate the effect of TSA on baroreflex function, the cross spectral gain, phase, and coherence between beat-to-beat BP and HR signals were calculated by using transfer function analysis. RESULTS: With the onset of TSA, BP and HR significantly decreased. TSA significantly decreased the low frequency (LF) and high frequency (HF) components of HRV and BPV. Baroreflex sensitivity (BRS) obtained from transfer function gain between these variables was significantly decreased. CONCLUSIONS: TSA reduces the LF and HF components of HRV and BPV. These suggest that TSA in rats decreases both parasympathetic and sympathetic drive. Moreover, the decrease in BRS suggests impairment of cardiac baroreflex buffering function during TSA.

Effects of Respiratory Rate on Cardiovascular Variability under General Anesthesia with Mechanical Ventilation / 대한마취과학회지

BACKGROUND: Although heart rate variability (HRV) and blood pressure variability (BPV) arise from many different influences, probably the most consistent external modulator is respiration. At rest, the heart rate increases on inspiration and decreases on expiration, a phenomenon called respiratory sinus arrhythmia (RSA). Spectral analysis of heart rate offers good and reproducible estimate of RSA and BPV. Many studies have been conducted on the effects of respiration on HRV and BPV during awake subject breathing spontaneously. However, little is known as to whether respiratory rate modulates HRV and BPV during general anesthesia with mechanical ventilation. Here, we studied effects of respiratory rate on HRV and BPV during general anesthesia. METHODS: We studied 40 patients undergoing general anesthesia with mechanical ventilation. Maintaining anesthesia with isoflurane, we recorded R-R interval and systolic blood pressure at respiratory rate of 15, 10 and 6 breaths/minute. Data was analyzed by the power spectral analyses of HRV and BPV, which were divided into low frequency (LF) and high frequency (HF) band. RESULTS: Respiratory rate did not affect RR interval, systolic blood pressure, and total spectral power HRV and BPV. Compared with its value at 15 breaths/minute, HF-HRV was significantly increased at 6 breaths/minute. HF-and LF-BPV at 6 breaths/minute were significantly increased versus 15 breaths/minute. CONCLUSIONS: Respiratory rate modulates HRV and BPV during general anesthesia with mechanical ventilation. We suggest that respiratory rate should be considered and controlled in studies of cardiovascular variability during general anesthesia.