A new method of continuous propofol infusion for total intravenous anesthesia]

Total intravenous anesthesia (TIVA) is recommended to avoid air pollution. However, intermittent administration of anesthetic agents has a large disadvantage of delayed emergence time. We suggested continuous TIVA with propofol, ketamine, vecuronium and buprenorphine (PKBp), and reported that maintenance with continuous intravenous administration of propofol corresponding to the age associated with ketamine (240 micrograms.kg-1.h-1), vecuronium (80 micrograms.kg-1.h-1) and buprenorphine (0.4 microgram.kg-1.h-1) brought rapid emergence and that the last 1/6 of anesthetic time was the point to reduce propofol maintenance dose. In this study, we maintained anesthesia with continuous intravenous administration of propofol using twice step down method every one hour. We conclude that the reduction of propofol maintenance dose for every 1/6 in one hour produces fewer dropout cases.     

Economical benefit of continuous total intravenous anesthesia]

Total intravenous anesthesia (TIVA) has been recommended in view of avoiding air pollution. However, intermittent administration of anesthetic agents has a large disadvantage of delayed emergence. We reported that continuous TIVA with propofol, ketamine, vecuronium and buprenorphine (PKBp) could bring rapid emergence. In this study, we calculated and compared the cost of anesthesia in the subjects who had undergone general anesthesia either with continuous PKBp or nitrous oxide-oxygen-sevoflurane. In group PKBp subjects, after induction with propofol, ketamine, vecuronium and buprenorphine, anesthesia was maintained with continuous intravenous administration of propofol corresponding to the patient's age using twice step down method; ketamine (240 micrograms.kg-1.h-1), vecuronium (80 micrograms.kg-1.h-1) and buprenorphine (0.4 microgram.kg-1.h-1). Group GOS subjects, after the same induction method, received nitrous oxide, sevoflurane and vecuronium. Moreover, the group GOS subjects were divided to two groups; the high flow GOS (N2O:O2:sevoflurane = 4 l:2 l:30 ml) and the low flow GOS (N2O:O2:sevoflurane = 2 l:1 l:15 ml). Continuous PKBp group showed lower cost than the high flow GOS group. The PKBp group showed lower cost than the low flow GOS group except in patients weighing more than 100 kg. Furthermore, we calculated the cost of continuous PKBp anesthesia in Japan, U.S.A. and U.K. The U.S.A. cost of PKBp was higher than the Japanese and the U.K., because the cost of ketamine in U.S.A. is higher than in the other countries. Continuous PKBp is more economical than the high flow GOS, and continuous PKBp in Japan is more economical than in U.S.A.     

The influence of age on hemodynamics and the dose requirements of propofol and buprenorphine in total intravenous anesthesia combined with continuous epidural anesthesia

A retrospective study was performed to determine the influence of age on hemodynamics and awakening time in total intravenous anesthesia (TIVA) using propofol and buprenorphine combined with continuous epidural anesthesia for abdominal surgery. Thirty-five patients (36-87 yr) were allocated to the following five groups by age: 36-49 yr, 50-59 yr, 60-69 yr, 70-79 yr and 80-87 yr. All patients were premedicated with midazolam i.m. Anesthesia was maintained with propofol infusion with 40% oxygen in air, intravenous buprenorphine plus vecuronium and continuous epidural anesthesia using 2% mepivacaine. After extubation, the epidural bolus dose (buprenorphine 0.1-0.2 mg with droperidol 1.25-2.5 mg) and epidural infusion (buprenorphine 17 micrograms.h-1 with droperidol 0.1 mg.h-1) were administered. Intraoperative heart rate (HR) and mean arterial pressure (MAP) decreased but remained within 30% of preanesthetic level. HR did not differ in five groups, although MAP decreased significantly in patients above 50 yr of age. The doses of midazolam (1-5 mg), propofol (2.7-7.4 mg.kg-1.h-1) and buprenorphine (40-200 micrograms) decreased with age (P < 0.01), while the maintenance doses of mepivacaine (40-140 mg.h-1) and vecuronium (0.03-0.09 mg.kg-1.h-1) showed no significant decrease. Awakening time was not significantly prolonged with age (r = 0.27, P = 0.12). Two patients in each group required analgesics within 20 hours. Neither nausea, respiratory depression nor awareness was found. We suggest that the combination of TIVA and continuous epidural anesthesia would be useful to maintain stable hemodynamic state and to obtain early recovery time, especially in the elderly.     

The changes in hemodynamics and dose requirements in total intravenous anesthesia using propofol and buprenorphine

A retrospective study was performed to evaluate the changes in hemodynamics and dose requirements in total intravenous anesthesia (TIVA) using propofol and buprenorphine without (Group S: spinal surgery (3-6 h), n = 8, 28-79 Y) or with (Group A: abdominal surgery (5-10 h), n = 15, 36-83 Y) epidural anesthesia. All patients were premedicated with midazolam i.m. (2-5 mg). Anesthesia was maintained with a single dose of buprenorphine (Group S: 1.9 +/- 0.4 micrograms.kg-1, Group A: 2.0 +/- 0.5 micrograms.kg-1), propofol infusion and vecuronium with 40% oxygen in air. Group A was supplemented with continuous epidural anesthesia using 2% mepivacaine. In Group A, mean arterial pressure (MAP) and heart rate remained stable after the start of surgery. However, in Group S, 2 hours after the start of surgery MAP increased (P < 0.05) and remained elevated (P < 0.05) at higher levels than those in Group A. The maintenance dose of propofol in Group A (4.0 +/- 1.1 mg.kg-1.h-1) was significantly smaller than in Group S (6.5 +/- 0.9 mg.kg-1.h-1). In both groups, infusion rates of propofol were unchanged from 1 hour after the start to the end of surgery. Infusion rates of mepivacaine (5.2 +/- 0.9 ml.h-1) were unchanged following the increase 2 hours after the start of surgery. Awakening times were within 25 min (Group S 11.3 +/- 7.2 min vs Group A 14.7 +/- 7.3 min). There was no awareness during anesthesia in either group. The results suggest that additional continuous epidural anesthesia in TIVA would be useful to reduce propofol dose, to stabilize hemodynamic state and to obtain rapid recovery in anesthesia of long duration.     

Use of propofol and buprenorphine for total intravenous anesthesia

A study was carried out in 47 patients undergoing general surgery and elective gynecological surgery under totally endovenous general anesthesia. For this purpose, propofol and buprenorphine were used in controlled ventilation with oxygen and air, totally excluding the use of nitrous oxide and halogenate vapours. The following parameters were measured to evaluate the state and depth of anesthesia: arterial pressure (systolic, mean, diastolic), heart rate, sweating, lacrimation (Evan's PRST). The awakening from anesthesia was evaluated using Steward's test. The results of monitoring show that the method represents a valid alternative to anesthesia using inhalatory techniques. Nonetheless, the Authors underline the need for further research on the subject.     

Recovery from total intravenous anesthesia with propofol and buprenorphine

A retrospective study was performed to evaluate recovery from total intravenous anesthesia (TIVA) with propofol and buprenorphine for various types of surgery. The patients of the study were divided into two groups; Group A: n = 85, age 66 +/- 12 Y, duration 282 +/- 102 min, with epidural block and Group B: n = 56, 52 +/- 20 Y, 172 +/- 90 min, without the block. All patients were premedicated with intramuscular midazolam (1-5 mg). Anesthesia was maintained with propofol infusion with 40% oxygen in air, and an intravenous bolus dose of buprenorphine (0.11 +/- 0.03 mg). Muscle relaxation was obtained by intravenous vecuronium. The patients of Group A were supplemented with continuous epidural anesthesia using 2% mepivacaine. The maintenance dose of propofol (Group A: 4.5 +/- 1.2 mg.kg-1.h-1, Group B: 7.0 +/- 1.8 mg.kg-1.h-1) and temperature at the end of surgery decreased significantly with age. Awakening time in all patients was 12.3 +/- 7.4 min and it was correlated significantly with age and hypothermia, but not correlated with the maintenance dose or duration of propofol infusion. In short-duration surgery (within 2 hours, n = 36) awakening time was correlated with neither age nor temperature. There was no difference in awakening time between genders. Requirement for analgesics within 20 hours was 18.8% in Group A and 14.3% in Group B. Four patients (2.8%) reported dreaming, but none of the patients recalled the intraoperative events. We suggest that in elderly patients the reduction of intravenous anesthetics, maintenance of normothermia and short-duration surgery would result in rapid recovery in TIVA.     

雷米芬太尼复合丙泊酚静脉麻醉的临床应用

目的观察雷米芬太尼复合丙泊酚静脉麻醉的效果。方法全身麻醉下腰椎手术患者60例,随机均分为雷米芬太尼复合丙泊酚静脉麻醉组(Ⅰ组)和静吸复合麻醉组(Ⅱ组)。雷米芬太尼和丙泊酚的负荷量分别为1μg/kg和1mg/kg,雷米芬太尼以0.5μg·kg-1·min-1速率输注。麻醉中通过增减雷米芬太尼0.1μg·kg-1·min-1输注速率调整麻醉深度。丙泊酚按5∶4∶3方案输注,即5mg·kg-1·h-1输注10min,4mg·kg-1·h-1输注10min,20min后3mg·kg-1·h-1恒速输注。观察两组气管插管反应、麻醉效果、苏醒质量。结果两组麻醉效果相同,均可抑制气管插管反应(P<0.01),且Ⅰ组较Ⅱ组明显(P<0.05)。Ⅰ组苏醒质量较Ⅱ组好(P<0.01),不良反应较Ⅱ组高(P<0.01),术中无知晓。结论雷米芬太尼复合丙泊酚用两个注射泵静脉麻醉,采用负荷量加两种以上速率输注全凭静脉麻醉简便易行。     

Comparison of pentazocine and fentanyl in total intravenous anesthesia using propofol

BACKGROUND: Pentazocine may be an alternative for fentanyl during total intravenous anesthesia (TIVA) using propofol. The authors compared the efficacy and safety of pentazocine for analgesics in TIVA using propofol. METHODS: Eighty-nine patients scheduled for mastectomy were analyzed retrospectively. Patients were classified into two groups by used analgesics; pentazocine (Group P, n = 34) and fentanyl (Group F, n = 55). Anesthesia was induced with propofol, using target controlled infusion method, and ketamine 20-50 mg, and was maintained with propofol infusion and increments of fentanyl or single dose of pentazocine with 40% oxygen in air. Postoperative pain was assessed using a visual analogue pain scale (VAS). RESULTS: There were no differences in the patient background between both groups. Systolic as well as diastolic blood pressure and heart rate were not different between both groups during surgery. The maintenance dose of propofol was not different between the two groups. Awakening time in about 80% of patients was within 15 minutes and is not different between the two groups. There were no differences between the two groups regarding VAS. There are no severe complications. Incidence of nausea and vomiting was not different between the two groups. CONCLUSIONS: The results suggest that pentazocine would provide a stable hemodynamic state, rapid recovery and an effective postoperative pain relief to the same degree as with fentanyl in TIVA with propofol.     

The influence of age on hemodynamics and the dose requirements of propofol and buprenorphine in total intravenous anesthesia

A retrospective study was performed to determine the influence of age on hemodynamics and awakening time in total intravenous anesthesia (TIVA) with propofol and buprenorphine for spinal surgery. Twenty patients (26-79 yr) were studied and allocated into following four groups by age: 26-49 yr, 50-59 yr, 60-69 yr, and elderly 70-79 yr. All patients were premedicated with midazolam (2.5-5 mg) i.m. Anesthesia was induced (60-180 ml.h-1) and maintained (20-60 ml.h-1) with propofol infusion with 40% oxygen in air, added with vecuronium and one single dose of buprenorphine (0.08-0.2 mg; 1.37-2.63 micrograms.kg-1) before incision. Mean arterial pressure was stable and did not differ in four groups. Heart rate was decreased (P < 0.01) in the elderly group compared with the group younger than 50 yr. Bradycardia (below 50 beat.min-1) occurred in 60% of the elderly group. An adequate dose of buprenorphine (microgram) was proposed as: 208 - 1.8 x age (yr) + 0.3 x weight (kg) (r = 0.90, P < 0.01). The induction and maintenance rates (ml.h-1) of propofol were decreased with age and increased with weight (P < 0.05). However, the maintenance dose of propofol (3.9-8.5 mg.kg-1.h-1) did not correlate with age. Awakening time was prolonged (P < 0.05) in the elderly group (17.0 +/- 7.2 min) as compared with the group of younger than 50 yr (8.0 +/- 3.9 min). The three patients requiring postoperative analgesics were younger than 60 yr. This study suggests that we should reduce the dose of buprenorphine with age in TIVA using propofol. About 50% of the dose given to the patient younger than 50 yr was considered adequate in the elderly group.     

Optimal dosage strategies in total intravenous anesthesia using propofol and ketamine

The combination of propofol and ketamine for total intravenous anesthesia was investigated; the intention was to minimize the side effects of each drug by the concomitant application of the other drug. METHODS. Twenty patients scheduled for lower abdominal interventions were divided into two groups. In the first group anesthesia was induced and maintained by a simple administration regimen based upon pharmacokinetic principles. Ketamine and propofol were given as bolus injections (60 mg each) with a time interval of 60 s for induction followed by a two-step infusion regimen for propofol (15.5 mg/min) and later on by an additional ketamine infusion (1-2 mg/min). Bolus injections (20 mg) of ketamine were administered to increase the depth of anesthesia if necessary (Fig. 1). The second group received propofol and ketamine by microprocessor-controlled infusion pumps requiring the anesthetist to operate a single dial to preset the desired blood levels of both drugs according to the needs of the individual patient (Fig. 2). RESULTS. There were no difference (Table 1) between the two groups in the demographic data of the patients or duration of surgery (30-120 min). The total doses of propofol (750 +/- 262 vs 624 +/- 468 mg) and ketamine (158 +/- 41 vs 99 +/- 48 mg) were smaller in the computer-controlled infusion group, though this difference just failed to be significant. The hemodynamic changes during induction were minor, with a small nonsignificant increase in all parameters (Fig. 3) for 10 min. The controllability of the pharmacodynamic effects of both drugs during anesthesia was very satisfactory in the computer-assisted infusion group and quite satisfactory in the first group. There were no psychic disturbances during induction of or recovery from anesthesia. Respiration was adequate within a few minutes after the end of surgery. The patients were awake about 10 min later and fully oriented after 20 min. No major side effects were observed with this anesthetic technique. CONCLUSION. Total intravenous anesthesia with propofol and ketamine proved to be very satisfactory from a clinical point of view. The major known side effects of propofol (reduced hemodynamics during induction) and ketamine (psychic disturbances and cardiovascular stimulation) were absent and respiratory function was adequate after the end of surgery. This technique, therefore, can be used in risk patients and under disaster conditions when i.v. access is the only possible route of drug administration. The use of computer-assisted infusion pumps markedly enhances handling and controllability of total i.v. anesthesia.     

A patient with pulmonary alveolar proteinosis who underwent whole lung lavage under total intravenous anesthesia with propofol]

A 32-year-old male suffering from pulmonary alveolar proteinosis underwent whole lung lavage under one-lung ventilation and total intravenous anesthesia with propofol and fentanyl. The lung lavage was initially performed for the right lung, and for the left lung two weeks later. Spo2 and Pao2 declined at the time of lung degassing and drainage of lavage fluid (minimum values; Spo2 = 83%, Pao2 = 55.9 mmHg), and recovered on filling with the lavage fluid. Although pulmonary arterial pressure and central venous pressure were slightly increased at the time of unilateral lung filling, there was no marked change in arterial pressure, heart rate or cardiac output for lavage of either lung. % VC, DLCO and PaO2 markedly improved after whole lung lavage, from 26.0%, 5.84 ml.min 1.mmHg-1, and 61.9 mmHg in room air to 41.6%, 9.96 ml.min-1.mmHg-1, and 89.3 mmHg in room air, respectively. Since propofol does not inhibit hypoxic pulmonary vasoconstriction and is able to maintain a stable level of anesthesia, it is a useful anesthetic agent for whole lung lavage.     

The effect of encephalogram bispectral index monitoring during total intravenous anesthesia with propofol in outpatient surgery]

OBJECTIVE: To assess the effect of monitoring the encephalogram bispectral index (BIS) during outpatient surgery. Outcome measures were amount of propofol administered, awakening and discharge. MATERIAL AND METHODS: Forty consecutive outpatient surgery patients were studied. The patients gave informed consent and received general intravenous anesthesia with propofol administered through a laryngeal mask using a computerized system (Diprifusor(R)). Two groups were formed: in group A, BIS was monitored, although the information was hidden from the anesthesiologists, who used the usual signs (loss of blinking reflex, pupil size and hemodynamic response) to guide anesthesia; in group B the anesthesiologists used BIS monitoring to guide propofol administration. Measurements were blood pressure, heart rate and BIS at six times during the procedure (T1-T6). Other data recorded were age, weight, height, propofol consumption in relation to weight and duration of procedure, consumption of rocuronium and alfentanil, duration of propofol infusion, time from withdrawal of propofol until eye opening, duration of stay in the post-anesthesia intensive care unit and time until total recovery. A questionnaire assessed the presence of intraoperative awareness and degree of satisfaction. The data were analyzed by Student's t and a chi square tests, with statistical significance at p < 0.05. RESULTS: Demographic variables (age, weight and height) were similar, as were duration of propofol infusion, total dose of alfentanil and rocuronium, evolution of blood pressure and heart rate. Statistically significant differences in BIS were observed at two times, T4 and T5; total propofol administered was 32.6% lower in group B; and time until eye opening was significantly shorter in group B. No significant differences were observed for time until full recovery. No instances of intraoperative awareness were reported and satisfaction was high in both groups. CONCLUSION: BIS monitoring allows for propofol titration that leads to a mean reduction of 32.6% in consumption, shortening the time until eye opening without causing intraoperative awareness or reducing patient satisfaction.     

A comparison of fentanyl and buprenorphine in total intravenous anesthesia using propofol during spinal surgery

A retrospective study was performed to compare the hemodynamic effect and postoperative pain relief of fentanyl (Group F, n = 11) and buprenorphine (Group B, n = 11) in total intravenous anesthesia (TIVA) using propofol during spinal surgery. All patients were premedicated with midazolam (3-5 mg) i.m. Anesthesia was maintained with propofol infusion, and increments of fentanyl or single dose of buprenorphine with 40% oxygen in air. Total doses of fentanyl and buprenorphine were 7.6 +/- 1.0 micrograms.kg-1 and 2.0 +/- 0.4 micrograms.kg-1, respectively. Maintenance doses of propofol (Group F: 5.5 +/- 0.8 mg.kg-1.h-1, Group B: 5.9 +/- 1.1 mg.kg-1.h-1) and vecuronium were not significantly different. Mean arterial pressures from 2 hours after incision to the end of surgery were elevated significantly in Group F than in Group B. Recovery time (Group F 12.5 +/- 6.1 min vs Group B 11.8 +/- 6.1 min) and extubation time (Group F 19.5 +/- 10.3 min vs Group B 15.0 +/- 7.0 min) were not different. At the end of anesthesia, seven patients in Group F and one patient in Group B (P < 0.01) complained of severe pain. All patients in Group F, and only two in Group B (P < 0.02) received analgesics within 20 hours. Neither nausea nor respiratory depression was found in both groups. This study suggests that buprenorphine would provide a more stable hemodynamic state and better postoperative pain relief than fentanyl in TIVA using propofol.     

Perioperative bleeding tendency in a hemodialysis patient during gastrectomy under total intravenous anesthesia using propofol infusion]

A 64-year-old female receiving hemodialysis (HD) underwent subtotal gastrectomy for gastric cancer under total intravenous anesthesia. Anesthesia was performed using continuous infusion of propofol (5-8 mg.kg-1.h-1), buprenorphine i.v. (2.5 micrograms.kg-1), 2% mepivacaine epidural infusion (7 ml.h-1) and appropriate doses of vecuronium. The blood pressure and heart rate were stable within 120% of the preoperative level. However, 3 and half hours after propofol anesthesia, increased bleeding from the surgical field was observed. The activated clotting time (ACT) was 144 seconds. Furthermore, at the end of the operation (5 hours after propofol anesthesia), the ACT (219 sec), PT (14.8 sec), PT-INR (1.94) and APTT (102.5 sec) were significantly prolonged. The platelet count was unchanged. The intraoperative total bleeding was 844 g. The total propofol infusion time and dose were 310 minutes and 1,580 mg, respectively. Immediate recovery with spontaneous ventilation was observed. Postoperative bleeding from the wound continued. Finally, 7 hours after the surgery, the bleeding ceased and the ACT (125 sec), PT (12.4 sec), PT-INR (1.34) and APTT (22.5 sec) were normalized. The total postoperative bleeding was 404 g. Despite the advantage of short-acting anesthetic agent, we suspect that propofol induced the bleeding tendency via platelet inhibition. This platelet inhibition may gradually increase with time and the dose of propofol. We should utilize propofol cautiously for patients receiving HD or with bleeding tendency.     

A benzodiazepine antagonist flumazenil in clinical use--a dose finding study

The effective dose, usefulness and side effects of flumazenil, a specific benzodiazepine antagonist, have been investigated in 72 sleeping patients after the end of the surgical operation who had received flunitrazepam 0.03 mg.kg-1, a long acting benzodiazepine. The patients received intravenous injections of flumazenil 0.1 mg, 0.2 mg, 0.4 mg and 0.8 mg per person as initial doses. Four minutes after the injection of flumazenil, the percentages of the patients who were awake, were 47.4% in 0.1 mg group, 82.4% in 0.2 mg group, 82.4% in 0.4 mg group and 88.2% in 0.8 mg group respectively. There were several side effects observed in all the groups except 0.2 mg group. However, they presented no clinical problems. Therefore, flumazenil 0.2 mg as the initial dose, is considered appropriate.     

Dose requirements of pentazocine during abdominal surgery in total intravenous anesthesia using propofol

BACKGROUND: To determine the dose requirements of pentazocine when administered as a single bolus dose in total intravenous anesthesia with propofol for abdominal surgery. METHODS : One hundred and fifty-six patients scheduled for abdominal surgery were analyzed retrospectively. Patients were classified into three groups according to duration of the operation ; under 120 min (Group 1, n=87) ; 120-240 min (Group 2, n=56) ; over 240 min (Group 3, n=13). Anesthesia was induced with propofol using target controlled infusion method, and was maintained with propofol infusion, pentazocine as a single dose before incision, and intermittent administration of vecuronium with 40% oxygen in air. RESULTS: Dosage of pentazocine was significantly increased according to length of the operation. The maintenance doses of propofol were not different among the three groups. Awakening time in about 80% of patients in each group was within 15 minutes. There are no severe complications. CONCLUSIONS : Total intravenous anesthesia with propofol and pentazocine is useful to stabilize hemodynamics and to achieve rapid recovery. For the operation within 120 min, 0.7 mg x kg(-1) of pentazocine is necessary whereas 0.8 mg x kg(-1) of pentazocine is needed in the operation of 120-240 min.     

Comparison of midazolam and propofol in combination with alfentanil for total intravenous anesthesia

Hemodynamic function during induction of anesthesia, the alfentanil and naloxone requirements, and the speed of recovery from total intravenous anesthesia with alfentanil/midazolam (group M, n = 10) or alfentanil/propofol (group P, n = 10) were compared in patients undergoing lower limb surgery. Twenty patients were randomly assigned to receive either 2 mg/kg propofol in 5 min followed by 9 mg.kg-1.h-1 for 30 min and 4.5 mg.kg-1.h-1 until skin closure, or 0.42 mg/kg midazolam in 5 min followed by 0.125 mg.kg-1.h-1 until skin closure. Simultaneously, a variable-rate infusion of alfentanil was given. Patients were ventilated with 30% oxygen in air. In both groups blood pressure and heart rate decreased significantly (P less than 0.02) and to a similar extent during induction. The total dose of alfentanil was similar in both groups. No patient in group P and nine patients in group M needed naloxone (average dose 130 +/- 70 micrograms, P less than 0.001). Recovery, as judged by psychomotor tests (90% score was reached at 1 h in the P group and at about 4 h in the M group, P less than 0.001), sedative scores, and orientation in time and place, was shorter in group P than in group M. The conclusion is reached that propofol is superior to midazolam in total intravenous anesthesia with alfentanil.