Anesthesia for Orthopedic Surgery in Patients Older than 80 Years / 대한마취과학회지

BACKGROUND: The number of elderly patients undergoing orthopedic surgery is steadily growing. Aging modifies the physiology, pharmacokinetics and pharmacodynamics, and co-morbidity is common in the elderly. Therefore, it is important and necessary to evaluate the anesthetic management for orthopedic surgery in elderly patients. METHODS: Four hundred and twenty two patients, older than 80 yr, who underwent orthopedic surgery, between September 1996 and March 2004, were retrospectively reviewed according to age, sex, operation site, preexisting concomitant disease, anesthetic techniques, postoperative complications and mortality. RESULTS: Three hundred and fifty seven patients had a pre-existing concomitant disease. There were no meaningful differences in the postoperative morbidity and mortality according to the anesthetic technique employed, although there was a clearly reduced incidence of deep vein thrombosis with regional anesthesia. There were significantly higher postoperative morbidity and mortality among patients with a pre-existing concomitant disease. CONCLUSIONS: Appropriate anesthetic management is suggested for patients older than 80 yr undergoing orthopedic surgery, which will require proper preoperative evaluation, sufficient vigilance of their hemodynamics and an awareness of impaired circulatory function, as well as other age related concerns.

Assessment of Cardiovascular Autonomic Function in Patients with Liver Cirrhosis Using Heart Rate Variability, Blood Pressure Variability and Baroreflex Sensitivity / 대한마취과학회지

BACKGROUND: Liver cirrhosis is associated with several hemodynamic abnormalities, including an impairment of autonomic nervous system reflexes, but very few have compared the disease severity with cardiovascular autonomic dysfunction assessed by spectral analysis of blood pressure and electrocardiogram. The aim of this study was to investigate the relationship between Child-Turcotte-Pugh (CTP) score and autonomic indices in patients with liver cirrhosis using the heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS). METHODS: Fifty patients scheduled for liver transplantation recipients under general anesthesia were enrolled in the study. Beat-to-beat blood pressure and RR interval were measured for five minutes before anesthesia induction. HRV and BPV were estimated by power spectral analysis of RR interval and systolic blood pressure. BRS was estimated by both the sequence method (Sequence BRS) and high frequency (HF) gain of transfer function analysis (HF BRS). RESULTS: Significant inverse correlations between CTP score and Sequence BRS (r = -0.61), HF BRS (r = -0.59), low frequency (LF) and HF power of HRV (r = -0.57, r = -0.46), LF power of BPV (r = -0.37) were found. However, no significant correlations were observed between CTP score and LF/HF ratio of HRV (r = -0.02) and HF power of BPV (r = 0.27). CONCLUSIONS: These results showed that autonomic dysfunction assessed by spectral analysis was associated with increasing severity of liver cirrhosis. Further study will be needed to clarify relationship between our findings and hemodynamic fluctuations during anesthesia for liver transplantation.

Assessment of the Mechanism of Arterial Blood Pressure Change during Sevoflurane Induction: Beat-to-Beat Analysis of Hemodynamic Variables Using a Modelflow Method / 대한마취과학회지

BACKGROUND: A modelflow method provides beat-to-beat analysis of cardiovascular variables based on arterial pulse pressure analysis. In this study, we assessed the mechanism of arterial blood pressure (ABP) change during sevoflurane induction by the analysis of beat-to-beat hemodynamic changes using a modelflow method. METHODS: Beat-to-beat ABP was measured during a stable conscious state (baseline) and vital capacity induction with sevoflurane 6 vol% and oxygen 8 L/min in 18 healthy living liver transplant donors. Alterations of beat-to-beat systolic ABP, mean ABP, diastolic ABP, heart rate (HR), stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) by sevoflurane induction were estimated noninvasively using a modelflow method simulating aortic input impedance from an ABP waveform. RESULTS: After sevoflurane induction, ABP, SV, CO, and TPR decreased significantly (all P < 0.05), but HR did not change significantly. After tracheal intubation, ABP, CO, and TPR did not change significantly compared with baseline, but HR increased and SV decreased significantly (both P < 0.05). CONCLUSIONS: Using a modelflow beat-to-beat analysis of cardiovascular variables, we found that ABP did not change significantly compared to baseline after tracheal intubation during sevoflurane induction, indicating the counteraction of increased HR and decreased SV, and that the reduction of SV by tracheal intubation suggests the suppression by increased HR and TPR compared with that after sevoflurane induction.

Change of Blood Pressure Variability before and during Sevoflurane Anesthesia / 대한마취과학회지

BACKGROUND: Relatively little is known about the effects of general anesthesia on blood pressure variability (BPV). This study was designed to evaluate the changes of high frequency (HF) and low frequency (LF) of BPV before and during general anesthesia with sevoflurane. METHODS: Beat-to-beat blood pressure was recorded at conscious baseline and during general anesthesia at 2% end-tidal sevoflurane in 17 healthy living-liver transplantation donors. BPV estimated by power spectra of systolic (SBP) and mean blood pressure (MBP) was calculated. RESULTS: Both LF power of SBP and MBP were diminished to 96.2% and 97.1% during sevoflurane anesthesia (5.5 +/- 2.8 to 0.2 +/- 0.2 mmHg2, 6.6 +/- 3.7 to 0.2 +/- 0.2 mmHg2, P < 0.001 for both). However, there were no significant changes of HF power of SBP and MBP during sevoflurane anesthesia. CONCLUSION: Sevoflurane anesthesia reduced noticeably LF power, which was associated with sympathetic vasomotor activity, but not HF power, which represents mostly the mechanical effect of respiration on blood pressure, of BPV.

Intubating Laryngeal Mask Airway for Difficult Airway / 대한마취과학회지

BACKGROUND: Almost all anesthesiologists are encounter a difficult airway occasionally, which is probably the most important cause of anesthesia related morbidity and mortality. The intubating laryngeal mask airway (ILMA; FastarachTM; laryngeal mask company, Henley-on-Thames, UK) is a new device for tracheal intubation. It is an ideal rescue airway since it can be placed quickly and used as a conduit for endotracheal intubation, while ventilation is ongoing. This prospective study was underttaken from January, 1997 to December, 2004 to evaluate the appropriateness of the ILMA for anticipated or unanticipated difficult airways. METHODS: After institutional committee approval, seventy eight patients were enrolled in this study. The anticipated group compromised thirty five patients and the unanticipated group forty three. In the unanticipated group, anesthesia was induced with thiopental sodium and vecuronium and maintained with enflurane or isoflurane, whereas in the anticipated group, awake intubation with nerve block was done before intubation. The success of the technique (within five attempts), the number of attempts, the durations of the successful attempts, and adverse events (desaturation, bleeding) were recorded. RESULTS: The rate of successful tracheal intubation with ILMA was 92.7%. The numbers of attempts and the times to success were not significantly different between the two groups. Adverse events occurred significantly more frequently in the unanticipated group. Conclusion: The ILMA is a useful device for the management of patients with a difficult airway and may be a valuable alternative to direct laryngoscopy or fiberoptic intubation when neck movement is unfavorable or in those with an unanticipated difficult airway.