Adequate Target Concentration of Propofol and Fentanyl for Total Intravenous Anesthesia by Target-controlled Infusion during Cesarean Section / 대한마취과학회지

BACKGROUND: Propofol has been used for the induction and maintenance of obstetric anesthesia for its potential benefit of rapid recovery and less post-anesthetic complications. In order to determine the safe application of target-controlled infusion of propofol and fentanyl during Cesarean section under general anesthesia, we have investigated the adequate target concentrations of each drug using the bispectral index and hemodynamic parameters. METHODS: Ninety-two pregnant women who received Cesarean section under general anesthesia were enrolled in this study. After preoxygenation, anesthesia was induced with thiopental 4 mg/kg and succinylcholine 1 mg/kg, and intubation was done. Vecuronium 0.1mg/kg I.V. was applied for muscle relaxation, and mechanical ventilation was maintained with N2O/O2 (2 L/2 L)-enflurane. EtCO2 was maintained between 30 35 mmHg. After delivery of the fetus, propofol and fentanyl was infused by a computer-assisted continuous infusion system with air/O2 (2 L/2 L). The bispectral index was monitored perioperatively. This study proceeded in three stages. In the first stage, thirty women were studied for titration of the target effect-site concentration of propofol that could maintain a bispectral index between 40 60 while maintaining the target concentration of fentanyl at 1.5 ng/ml. In the second stage, forty-two women were randomly assigned into the four different groups (F25, F50, F75, F100) at target fentanyl concentrations of fentanyl of 0.25, 0.50, 0.75 and 1.0 ng/ml for each group respectively. The adequate target concentration of fentanyl was titrated. In the third stage, twenty women were studied for assessment of the adequacy of target concentrations of propofol and fentanyl prospectively. RESULTS: The target effect-site concentrations (Ce, 95% confidence interval) that could maintain 50% and 95% of patients hemodynamically stable with the bispectral index within 40-60 were 2.41 (2.27-2.55) microgram/ml and 3.15 (2.95-3.50) microgram/ml for propofol, 0.32 (0.13-0.46) ng/ml and 0.84 (0.66-1.29) ng/ml for fentanyl. The pre-anesthetic bispectral index was 97.1+/-1.2 and it decreased maximally to 39.5+/-6.47 after thiopental injection and increased maximally to 83.6+/-6.3 before delivery and it was 80.6+/-6.9 for eye-open to verbal command during recovery. CONCLUSIONS: The adequate target effect-site concentrations of propofol and fentanyl for the maintenance of total intravenous anesthesia during Cesarean section were determined and these concentrations were validated prospectively.

Oculocardiac Reflex and Postoperative Recovery in Pediatric Strabismus Surgery: A Randomized Trial Comparing Four Anesthetic Techniques / 대한마취과학회지

BACKGROUND: Oculocardiac reflex (OCR) and postoperative nausea/vomiting are major complications of pediatric strabismus surgery. The aim of the study was to assess, in children undergoing strabismus surgery, the incidence of OCR and postoperative emesis with a inhalational and a intravenous technique. METHODS: 44 healthy children undergoing elective strabismus surgery as inpatients were randomly allocated to four anesthetic techniques: (1) induction with propofol, maintenance with propofol infusion and 50% N2O-O2 (propofol-N2O); (2) induction with propofol and fentanyl 1 microgram/kg bolus, maintenance with propofol infusion and 50% air-O2 (propofol-fentnyl-air); (3) induction with thiopental, maintenance with enflurane and 50% N2O-O2 (enflurane-N2O); (4) induction with thiopental and fentanyl 1 microgram/kg, maintenance with enflurane and 50% air-O2 (enflurane-fentanyl-air). RESULTS: The incidence of an OCR significantly increased in the propofol-fentanyl-air group as compared to the enflurane-N2O or enflurane-fentanyl-air groups. Times to extubation were shorter in the propofol- N2O group than in the propofol-fentanyl-air or enflurane-fentanyl-air groups. Alertness scores were lower in the propofol-N2O group than in the enflurane-N2O or enflurane-fentanyl-air groups. Postanesthetic recovery scores and nausea/vomiting during the 24 hr after the operation did not show any differences among the groups. CONCLUSIONS: We concluded that children undergoing strabismus surgery anesthetized with propofolfentanyl-air had more episodes of OCR, propofol-N2O had shorter times to extubation and higher alertness scores, and the addition of N2O or fentanyl to anesthetic regimen was not associated with nausea and vomiting.

Anesthetic Management for Awake Craniotomy with Scalp Nerve Block and Propofol/Fentanyl Infusion / 대한마취과학회지

BACKGROUND: If epileptogenic foci are close to eloquent areas of the brain, awakening is needed for functional mapping during seizure surgery. In these cases adequate analgesia and sedation are needed. However sufficient dosage of intravenous anesthetics leads to many side effects. The authors used propofol and fentanyl infusion combined with scalp nerve block to reduce the severity of side effects from overdose of anesthetics. METHODS: The subjects were adult patients who would undergo awake craniotomy. After administering fentanyl 50~100 mcg intravenously, scalp nerve block was done to supraorbital, supratrochlear, auriculotemporal and lesser and greater occipital nerves of the surgical side with 0.25% bupivacaine containing 1 : 200,000 epinephrine. The anterior temporal region was infiltrated with the same local anesthetics. Oxygen was given by nasal cannula. During operation fentanyl was infused. Propofol was infused except during the awake period. Invasive arterial blood pressure, end-tidal CO2 and respiratory rate were monitored throughout the operation and arterial blood gas analysis was done intermittently. RESULTS: During total anesthesia time (410.3 39.9 min) propofol 16.2 6.3 mg/kg and fentanyl 11.9 3.7 mcg/kg were administered. The results of scalp nerve block were satisfactory. Brain swelling and transient decrease in respiratory rate were noticed in six patients and oxygen desaturation to 94% in one patient. All the patients were cooperative and the above problems were solved by reducing drug infusion rates. CONCLUSIONS: Propofol and fentanyl infusion with scalp nerve block may be an adequate method of anesthetic management for awake craniotomy.

Inhibitory Effects of Cough Reflex Induced from Fentanyl According to the Dose of Propofol / 대한마취과학회지

BACKGROUND: Bronchodilation effect of propofol was known that it could prevent bronchoconstriction induced by fentanyl administration. The aim of this study was to investigate the dosage of propofol that inhibited cough reflex induced from fentanyl. METHODS: One hundred twenty patients were randomly allocated to four groups: Group 1 (n=30, fentanyl 3 microgram/kg), Group 2 (n=30, propofol 0.5 mg/kg, fentanyl 3 microgram/kg), Group 3 (n=30, propofol 1 mg/kg, fentanyl 3 microgram/kg), Group 4 (n=30, propofol 2 mg/kg, fentanyl 3 microgram/kg). Patients in Group 1 were injected fentanyl within a second. Other patients groups were injected fentanyl two minutes after administration of propofol dosage, respectively. We checked cough response, oxygen desaturation and chest wall rigidity. RESULTS: There was no significant difference in the incidence of cough response between Group 1 and 2. But, the incidence of Group 3 and 4 was significantly lower than in Group 1 and 2. CONCLUSIONS: Propofol of clinical doses for anesthetic induction inhibit cough reflex induced from fentanyl.

A Case of Total Intravenous Anesthesia Using a Propofol-Fentanyl Computer Asssisted Continuous Infusion: A case report / 대한마취과학회지

The technique of computer-assisted continuous infusion (CACI) has revolutionised the administration of drugs by intravenous infusion. A stable blood concentration is achieved rapidly with CACI, allowing the anesthesiologist to monitor therapeutic effect and titrate drug concentrations accordingly. Propofol and opioids can be administered by CACI for the induction and maintenance of anesthesia in adult patients. Also, the ability to maintain a constant blood concentration of drugs is also extremely important for studying the pharmacodynamic interactions of drugs, and research in the area has increased with advent of CACI. We experienced a case of total intravenous anesthesia which was totally conducted by CACI, using a Master TCI for propofol and Stelpump program for fentanyl infusion.