The Effect of Anesthetics on Somatosensorily Evoked Potentials during Surgery / 대한마취과학회지

BACKGROUND: Many methods are available for the monitoring of spinal cord injury during an operation. During anesthesia, somatosensily evoked potentials (SSEP) may undergo substantial changes in the latencies and amplitudes which may be interpreted as pathological. It is essential for the anesthesiologist to know the potential interactions between anesthetic drugs and neurophysiologic responses during operation. The depressant effect of inhalation agents on the central nervous system exceeds commonly used intravenous anesthetics. Therefore, intravenous anesthesia is preferred to inhalation agents. This study was designed to compare the effects of intravenous anesthetics (propofol and fentanyl) and inhalational anesthetics (enflurane and nitrous oxide) used in the operation room. METHODS: According to the inclusion criteria of ASA I-II, 40 patients who were free of neurologic disease with electric abdominal operations were randomly selected. The baseline of the SSEPs were recorded with stimulation of the posterior tibial nerve at the ankle. After obtaining the baseline (preinduction) of the SSEPs, intravenous anesthetics (propofol 10 mg/kg/h, fentanyl 1 2 microgram/kg) and inhalational anesthetics (end tidal enflurane concentration 1.0 vol %, 50% nitrous oxide in oxygen) were administered. 30 minutes after induction (steady state), additional SSEPs were recorded. Mean arterial pressure, heart rate, temperature and arterial blood carbon dioxide tension were monitored. RESULTS: There were no significant differences in the baseline of SSEPs between the intravenous anesthetics group and the inhalational anesthetics group. There were no significant differences in latencies and amplitudes between the preanesthesia state and the postanesthetia state in the intravenous anesthetics group. But the inhalational anesthetics group revealed prolonged latencies in the postanestesia state as compared with their preanesthesia state. CONCLUSIONS: The above findings suggest that the use of intravenous anesthetics can be beneficial to intraoperative SSEP monitoring for possible damage to the central nervous system during operations.

Propofol-Fentanyl Total Intravenous Anesthesia for Coronary Artery Bypass Graft / 대한마취과학회지

BACKGROUND: Total intravenous anesthesia (TIVA) is by definition a technique involving the induction and maintenance of the anesthetic state with intravenous drugs alone. In particular, propofol and opioid and muscle relaxants allow enhanced control of the state of anesthesia for the entire duration of the surgical procedure. We evaluated the clinical usefulness of TIVA with fixed fentanyl concentration 3 ng/ml using isoconcentration nomogram and titrated propofol for coronary artery bypass graft. METHODS: Anesthesia was induced using 1% propofol mixed with lidocaine 0.5 mg/kg and ephedrine 10 mg (150 ml/hr) until loss of consciousness in 19 patients undergoing coronary artery bypass graft. Infusion rate of propofol was adjusted in response to blood pressure and pulse rate. To achieve constant fentanyl concentration, infusion rate of fentanyl was changed timely according to isoconcentration nomogram. Infusion of propofol and fentanyl was discontinued 15 and 30 min before predictable end of surgery, respectively. Intraoperative hemodynamics, recovery profile and postoperative analgesic requirements were checked. RESULTS: Overall intraoperative hemodynamics including cardiac index and PCWP showed no significant changes compared with preinduction control value except during CPB period. Average flow rate of propofol and fentanyl was 3.4 0.2 mg/kg/hr and 2.8 0.4 g/kg/hr, respectively. Spontaneous eye opening time was 96.4 min after discontinuation of fentanyl. More than 80% (16/19) of patients did not require any analgesic during first postoperative 24hrs for pain relief. CONCLUSIONS: TIVA with propofol and fentanyl (3 ng/ml) could be a suitable and safe anesthetic technique for coronary artery bypass graft.

Comparison of Intubation Following Propofol-Fentanyl with Intubation Following Succinylcholine-Thiopental Sodium / 대한마취과학회지

BACKGROUND: This study was performed to determine the effect of a endotracheal intubation & induction of anesthesia using propofol 2.0 mg/kg or 2.5 mg/kg and fentanyl 2 g/kg without succinylcholine chloride. Also we have compared this method with technique using succinylcholine 1.5 mg/kg and thiopental sodium 5 mg/kg. METHODS: They were divided into 3 groups as follows: group 1, succinylcholine 1~1.5 mg/kg and thiopental sodium 5 mg/kg; group 2, propofol 2 mg/kg and fentanyl 2 microgram/kg; group 3, propofol 2.5 mg/kg and fentanyl 2 microgram/kg. Systolic arterial pressure (SAP) and diastolic arterial pressure (DAP), and heart rate (HR) were measured before induction, after induction, after tracheal intubation immediately, at 1, 2, 3, and 5min. after tracheal intubation in all patients. The incidence of adverse effects and the quality of condition for intubation were measured in all patients. RESULTS: There were significant increases in SAP, DAP, HR after intubation in group 1 but significant decreases in SAP, DAP after induction and at 5min. after intubation in group 2 and group 3. The incidence of adverse effects, and the quality of condition for intubation were no significant difference between group 1 and group 3. CONCLUSIONS: From the above result, use of propofol 2.5 mg/kg and fentanyl 2microgram/kg provided a satisfactory alternative to succinylcholine and thiopental sodium for rapid sequence induction of anesthesia.

Comparison of Propofol-N2O and Propofol-fentanyl Anesthesia for Outpatient Surgery / 대한마취과학회지

BACKGROUND: The choice of anesthetic agents and adjuvants during outpatient surgery is of critical importance. Propofol is widely used for the induction and maintenance of outpatient anesthesia. Because propofol lacks analgesic properties, very high concentrations may be required when propofol is used as the sole anesthetic drug. Propofol is used with adjuvants such as nitrous oxide or opioid. This study was designed to evaluate the intraoperative hemodynamic response, recovery characteristics and side effects of propofol-fentanyl anesthesia compared with propofol-N2O anesthesia for outpatient surgery. METHODS: Twenty six healthy and unpremedicated patients scheduled for outpatient surgery were randomly allocated to receive either propofol-N2O anesthesia (N-group) or propofol-fentanyl anesthsia (F-group). The patients in N-group were ventilated with nitrous oxide 60~70% in oxygen and the patients in F-group were ventilated with oxygen 40% in nitrogen via laryngeal mask airway (LMA). RESULTS: There was no significant difference in blood pressure during anesthesia, recovery time and side effects between two group. There was significant decrease of heart rate in F-group. CONCLUSION: We concluded that nitrous oxide and fentanyl are reasonable adjuvants of propofol anesthesia in outpatient anesthesia.