Effect of Laryngoscopic and Tracheal Intubation Duration on Hemodynamic Response during Anesthetic Induction with Thiopental, Fentanyl and Rocuronium / 대한마취과학회지

BACKGROUND: Laryngoscopic and tracheal intubation often causes an increase in blood pressure and heart rate. The purpose of this study was to evaluate the influence of the duration of laryngoscopy and tracheal intubation on hemodynamic response. METHODS: We studied 110 patients undergoing elective surgery. Anesthesia was induced with fentanyl 1microgram/kg and thiopental 5 mg/kg, and rocuronium 0.6 mg/kg was administrated prior to intubation. The duration of laryngoscopy and tracheal intubation was defined as the interval between the insertion of a laryngoscope into a patient's mouth and its removal after successful tracheal intubation. Patients were divided into three groups according to the duration of intubation: Group 1 (duration 30 seconds). Systolic blood pressure, diastolic blood pressure and heart rate were measured before intubation, after induction, immediately after intubation, and 1 min and 3 min after intubation. RESULTS: Systolic blood pressure at 1 min after intubation was significantly higher in Group 3 than in Group 1, but no significant differences were observed in diastolic blood pressure or heart rate. Regarding the correlation between systolic blood pressure and the duration of laryngoscopy and tracheal intubation, the linear regression r2 value was 0.03. CONCLUSION: This study suggests that the duration of laryngoscopy and tracheal intubation is not significantly correlated with blood pressure. However, it also shows that when the time to intubation exceeds 30 seconds, that the systolic blood pressure is significantly increased. Thus, when the duration of tracheal intubation is anticipated to be prolonged, attempts to attenuate hemodynamic response to tracheal intubation are necessary.

Evaluation of LMA Insertion with Sevoflurane 8% and N2O after Midazolam Administration / 대한마취과학회지

BACKGROUND: Sevoflurane is characterized by the lack of an unpleasant odor, airway irritation and its low blood/gas partition coefficient (0.68), which provides rapid and smooth induction. Inhaled induction with sevoflurane is commonly used in pediatric patients, but not in adult patients. This study was designed to investigate the time to completion of LMA insertion and end-tidal sevoflurane concentration during induction with sevoflurane 8% and N2O 50%, after midazolam administration, in adults. METHODS: Twenty eight patients, aged 20(-60) years, were administered intravenous midazolam 30 microgram/kg and after one minute, sevoflurane 8% and N2O 50% were inhaled with tidal-volume breathing. One minute after loss of consciousness, jaw thrust and mouth opening were checked and an LMA was inserted. The end-tidal concentration of sevoflurane, and the times to loss of consciousness and completion of insertion were recorded. The mean arterial pressure and heart rate were also recorded. RESULTS: From initiation of sevoflurane and N2O inhalation, it took 48 +/- 14 seconds until loss of consciousness, and 143 +/- 19 seconds until the completion of LMA insertion. The end-tidal sevoflurane concentration was 4.1 +/- 0.6% at loss of consciousness, 5.0 +/- 0.7% at one min after loss of consciousness, and 4.1 +/- 0.5% after LMA insertion. In all patients LMA insertion was successful and satisfactory. After LMA insertion, compared to baseline, the mean arterial pressure was reduced and the heart rate increased. CONCLUSIONS: After small-dose of midazolam, inhaled induction with sevoflurane 8% and N2O 50% allowed successful and satisfactory LMA insertion in adults.

Clinical Significance of Preanesthetic Evaluation of Elderly Patients for Elective Surgery / 대한마취과학회지

BACKGROUND: There are few preoperative assessments focused on elderly surgical patients in Korea. Current study suggest that preoperative tests should be ordered only when the history or finding on physical examination have indicated for test. We performed a study to evaluate the preoperative assessment and to determine the need for routine preoperative laboratory test in elderly patients. METHODS: Three hundred forty-five patients aged 65 yrs or older presenting for elective surgery requiring general or regional anesthesia were divided into three groups according to age. Data was obtained from chart review and anesthesia preoperative records. Demographic information included age, sex, body mass index, coexisting disease, type of surgery and ASA classification. Clinically obtained preoperative laboratory test results (hemoglobin, platelet, chest X-ray, ECG, BUN, creatinine, ALT, AST, arterial blood gas analysis, pulmonary function test, PT, PTT, echocardiography) were measured. RESULTS: Fifty-seven percent were women. The most frequently performed procedures were general surgery followed by orthopedic surgery. In 345 patients, 47.5% of the patients had a coexisting disease. The most frequently coexisting disease was hypertension. 78.6% of the patients were classified as ASA class 2 and 3. The abnormal findings on ECG, pulmonary function test, and chest X-ray were 46.4%, 48.3%, and 42.6% respectively. 48 patients without any clinical history and symptoms had abnormalities on the routine laboratory test. CONCLUSIONS: We demonstrated that 47.5% of the patients had a coexisting disease and the majority of the patients were classified as ASA class 2 and 3. Changes in the cardiovascular and respiratory function were greater than other functions. We concluded that routine preoperative laboratory test in elderly is useful as a part of preoperative assessment.

Hemodynamic Effect of Propofol and Esmolol under Isoflurane Anesthesia in Dogs / 대한마취과학회지

BACKGROUND: Propofol has gained widespread popularity but it should at least be questioned in the presence of heart rate lowering medications such as beta-blockers. Esmolol, due to its ultrashort action and cardioselective properties, has been shown to be safe and effective for use in intraoprative tachycardia and hypertension. The purpose of this study is to evaluate the hemodynamic effects of esmolol and propofol under isoflurane anesthesia in dogs. METHODS: Six-mongrel dogs were induced with thiopental, intubated and ventilated with a mixture of isoflurane (1-1.5 vol%) and oxygen. A pulmonary artery catheter was placed via femoral vein and the femoral artery was cannulated. After stabilization, baseline hemodynamic measurements (HR, MAP, CO, SVR) were obtained. Measurements were repeated 5 and 15 minutes after injection of propofol (2 mg/kg), esmolol (1 mg/kg), and additional esmolol (1 mg/kg) for 30 seconds. Data was analyzed by repeated measurement of ANOVA. P < 0.05 was considered significant. RESULTS: Propofol produced no change in heart rate, MAP, CO and SVR. Heart rate decreased significantly during esmolol administration and remained decreased up to 15 minutes after the injection whereas the MAP, CO and SVR showed no significant changes. CONCLUSIONS: We have demonstrated that the decrease in heart rate continued up to 15 minutes after esmolol administration. These findings suggest that concomittent administration of propofol and esmolol requires monitoring of the heart rate after a bolus intravenous injection of esmolol.