The Effect of Clonidine Pretreatment on Cardiovascular Response and Seizure Duration according to Electroconvulsive Therapy / 대한마취과학회지

BACKGROUND: Elecroconvulsive therapy (ECT) is frequently associated with cardiovascular complications such as hypertension and tachycardia. The aim of this study was to evaluate whether clonidine given as an oral preanesthetic medication would influence the hemodynamic stress response, peripheral oxygen saturation and seizure duration which follows ECT. METHODS: Twenty-two ASA physical status I, II patients with major depressive disorders were included in a crossover study design and assigned randomly to either a control group who received placebo, or a clonidine group who received oral clonidine of 3 microgram/kg 90 min before preparation of ECT. All patients received glycopyrrolate 0.2 mg intramuscularly 60 min before anesthetic induction. Electrocardiography, pulse oximetry, and blood pressure monitors were applied to all patients. Patients were pre-oxygenated with 100% O2. Patients received thiopental 2.5 mg/kg and succinylcholine 0.5 mg/kg for anesthetic induction. Noninvasive mean arterial blood pressure (MAP), heart rate, and oxygen saturation were recorded just before test drug administration, immediately before ECT, and each minute for five minutes after ECT. The times from ECT stimulus to the cessation of clonic-tonic motor activity in the "isolated" arm were noted. RESULTS: There was a significant decrease in MAP (P = 0.007) through the peri-ECT period in groups with oral clonidine pretreatment (3 microgram/kg) relative to the control group. There were no significant differences in heart rate and peripheral oxygen saturation values between two groups. The duration of motor seizure activity was similar between the clonidine pretreatment and placebo groups. CONCLUSIONS: We conclude that oral clonidine 3 microgram/kg as a pretreatment medication is effective in attenuating the MAP increase in routine ECT.

Inaccurate Reading of Pulse Oximeter Due to Methemoglobinemia: A case report / 대한마취과학회지

Pulse oximeters measure the arterial oxygenation by determining the color of the blood between a light source and a photodetector. The light source consists of two light-emitting diodes (LEDs) that emit light at known wave lengths, 660 nm red light and 940 nm infrared light. The ratio of pulse-added red absorbance at 660 nm to pulse-added infrared absorbance at 940 nm is used to generate the oximeter's estimate of arterial saturation (SpO2). Pulse oximeters can determine the concentration of only two hemoglobins, reduced (HHb) and oxyhemoglobin (HbO2), so they can't distinguish the dyshemoglobins (methemoglobin, carboxyhemoglobin) which have light absorbances similar to that of HHb or HbO2. If the concentration of dyshemoglobin is above the normal range, pulse oximeters would give erroneous SpO2 readings. We experienced a case which showed a low SpO2 reading but had normal ABGA findings due to unsuspected methemoglobinemia.

Survey of the Knowledge about Pulse Oximetry in Medical Personnel / 대한마취과학회지

BACKGROUND: Pulse oximetry has been recommended as a standard of care for ICU, CCU, Post Anesthetic Care Unit as well as general anesthesia. The device provides valuable data regarding blood oxygenation. But there are some limitations and inaccuracies of pulse oximetry. The purpose of the present study is to assess the knowledge of pulse oximetry in the doctors and nurses who frequently use pulse oximeter in their practice. METHODS: We investigated 29 doctors(resident) and 41 nurses who answered a structured questionnaire about pulse oximetry. Questions were given about the knowledge of equipment, factors affecting readings, normal values in various patients, values in hypothetical clinical situations, education experience and source of information about pulse oximetry. RESULTS: Only 20% of doctors understood how a pulse oximeter worked and about 60% of doctors and 80% of nurses were confused about factors influencing readings. About 30% of doctors and 12% of nurses had received formal training about the pulse oximetry. Sources of information about pulse oximetry were operating manual, senior, books and journal. CONCLUSION: Our survey revealed that most of resident doctors and nurses using pulse oximeter were untrained, lacked knowledge of the basic principles and factors influencing saturation values in pulse oximetry. Therefore the systematic training program is important for doctors and nurses to use of pulse oximeter.(Korean J Anesthesiol 1996; 31: 791~796)

Survey of the Knowledge about Pulse Oximetry in Medical Personnel / 대한마취과학회지

BACKGROUND: Pulse oximetry has been recommended as a standard of care for ICU, CCU, Post Anesthetic Care Unit as well as general anesthesia. The device provides valuable data regarding blood oxygenation. But there are some limitations and inaccuracies of pulse oximetry. The purpose of the present study is to assess the knowledge of pulse oximetry in the doctors and nurses who frequently use pulse oximeter in their practice. METHODS: We investigated 29 doctors(resident) and 41 nurses who answered a structured questionnaire about pulse oximetry. Questions were given about the knowledge of equipment, factors affecting readings, normal values in various patients, values in hypothetical clinical situations, education experience and source of information about pulse oximetry. RESULTS: Only 20% of doctors understood how a pulse oximeter worked and about 60% of doctors and 80% of nurses were confused about factors influencing readings. About 30% of doctors and 12% of nurses had received formal training about the pulse oximetry. Sources of information about pulse oximetry were operating manual, senior, books and journal. CONCLUSION: Our survey revealed that most of resident doctors and nurses using pulse oximeter were untrained, lacked knowledge of the basic principles and factors influencing saturation values in pulse oximetry. Therefore the systematic training program is important for doctors and nurses to use of pulse oximeter.(Korean J Anesthesiol 1996; 31: 791~796)