Blood and central venous pressure responses after serial tourniquet deflation during bilateral total knee replacement.

Thirty-five patients who underwent one-stage bilateral total knee replacement were included in this study to determine whether there was any difference in hemodynamic effects following the deflation of the first and second tourniquets. The values of hemodynamic variables were not significantly different immediately before either the first or the second tourniquet release as compared to preoperative values. The changes in heart rate after the release of the first and second tourniquets showed similar patterns. The systolic and diastolic blood pressure decreased significantly after deflation of the first and second tourniquets. However, the decrease was more marked after the second tourniquet deflation. The level of central venous pressure decreased significantly after the release of the first and second tourniquets but the patterns of change were not significantly different. The need for administration of ephedrine was also higher after the deflation of the second tourniquet than after the first. We conclude that the blood pressure changes after the second tourniquet deflation are more pronounced than those following the first tourniquet deflation. Anesthesiologists must be aware of this phenomenon and prevent marked hemodynamic changes that could be detrimental to high-risk patients.

Propofol modifies recovery from isoflurane-nitrous oxide anesthesia.

A randomized, prospective study was performed to evaluate the hemodynamic changes and recovery characteristics in 60 ASA physical status class I-II unpremedicated patients undergoing gynecological laparotomies with either isoflurane anesthesia only (ISO group) or isoflurane anesthesia followed by propofol infusion (ISO-PRO group). All patients received isoflurane 0.5-1.5% and nitrous oxide (N2O) 66% in oxygen after tracheal intubation. ISO-PRO group (n = 30) received 6 mg kg-1 hr-1 propofol infusion in substitution for isoflurane 25 minutes before the end of surgery. Propofol in ISO-PRO group and isoflurane in ISO group (n = 30) were discontinued 5 minutes before the end of surgery. In both groups, N2O was administered throughout the operation until skin was closed. Hemodynamic measurements were similar between the two groups except at extubation when heart rate and blood pressure were lower in ISO-PRO group. The maximal blood pressure was also lower in ISO-PRO group. In ISO-PRO group, the time required to responsiveness to verbal commands and to orientation were significantly shorter. ISO-PRO group had better Steward's score on arrival at the recovery room and was earlier to get a full score of six. The two groups experienced similar rates of emesis and excitement either two hours or 24 hours postoperatively. We conclude that in relatively long intra-abdominal operations, replacement of isoflurane by propofol infusion 25 minutes before the end of surgery may provide stable maintenance of anesthesia and a faster recovery.

Precipitation profile of the intravenous induction agents.

To investigate the formation of precipitation between various intravenous agents, we cross-matched the anesthetic agents commonly used in the induction phase. Thiopentone and thiamylal precipitated in combination with non-depolarizing muscle relaxants, lidocaine, morphine, and meperidine. Ketamine and etomidate were naive to these agents. Crystalloidal solutions, such as lactated Ringer, normal saline, and dextrose solution did not contribute to the formation of precipitate. In conclusion, our study indicates that intravenous line must be irrigated before and after thiopentone and/or thiamylal. In order to prevent precipitate formation, mixtures of various drugs should be avoided until in vitro assay is done.

Neuromuscular blockade of the fetus with pancuronium or pipecuronium for intra-uterine procedures.

Fetal movement during intra-uterine fetal therapy makes these procedures technically more difficult and increases the likelihood of trauma to the fetus. Pancuronium or pipecuronium were used in a randomised study to temporarily arrest movement in 16 fetuses undergoing intra-uterine procedures. Under ultrasound guidance, pancuronium or pipecuronium 0.2 mg.kg-1 was injected into the fetal gluteal region. Fetal movements ceased within 4.6 +/- 2.3 min in the pancuronium group and 4.5 +/- 2.8 min in the pipecuronium group and returned by 115 +/- 26 min in the pancuronium group and 121 +/- 32 min in the pipecuronium group. No adverse effects of the relaxant were observed in the mothers. There was no evidence of soft tissue, nerve or muscle damage at the fetal injection site after delivery. Both muscle relaxants provided a safer method for diagnostic and therapeutic procedures. However, four cases in the pancuronium group (50%) developed a fetal tachycardia, and two cases in the same group showed loss of beat-to-beat variability. Pipecuronium appeared to be more suitable for intra-uterine procedures.

Oral complications associated with endotracheal general anesthesia.

A series of 745 consecutive cases of endotracheal anesthesia were collected at the National Taiwan University Hospital. Evaluation of the oral conditions was performed before, during and after the anesthesia. Injuries to oral structures were recorded. An 18% incidence of oral injuries was noted and the frequency for dental damage was 12.1%. Maxillary incisors, especially the left ones, were accident-prone. Risk factors identified in this study included large decay or restoration, advanced periodontitis, presence of dental prosthesis, shedding deciduous tooth, class II jaw relationship and anterior crowding. More than one third of the complications occurred during the maintenance or emergence stage of the anesthesia. Recommendations for prevention and management of this problem were given.

Retrospective evaluation of general anesthesia for oral and maxillofacial surgery during a 10-year period (1976-1985).

Anesthetic cases of oral and maxillofacial surgery during the period 1976-1985 were reviewed. There was a total of 653 cases, and the most frequently performed operation in this series was open reduction of maxillofacial bone fracture (22.8%). Special clinical problems were encountered in the 72 cases (11.02%) who underwent surgery for osteoradionecrosis, because most of them suffered from trismus and stiff neck. Nasotracheal intubation was more commonly used (84.69%). Sixty six cases received tracheostomy since they suffered from serious trismus and/or severe maxillofacial fracture. The recently introduced method of induction using etomidate and fentanyl seemed effective in maintaining hemodynamic stability. In 147 cases (22.51%), the anesthesia lasted more than 4 hours. In 366 cases (56.04%), a local infiltration of the operation field was performed with 1:100,000 epinephrine. Of these, 76 cases developed cardiac arrhythmia, mainly VPC (ventricular premature contraction) 12 of whom had a history of preoperative cardiac arrhythmias. The incidence of preoperative medical disease was 10.27%, the most common being cardiovascular (32.84%) and respiratory (26.87%) disease. Complications occurred during anesthesia in 122 cases (18.69%) with a high incidence of cardiac arrhythmia (67.21%).

Low dose of intrathecal hyperbaric bupivacaine combined with epidural lidocaine for cesarean section--a balance block technique.

The present study was designed to develop a combined spinal/epidural anesthetic technique for cesarean section. We compared the effects of different doses of intrathecal hyperbaric bupivacaine (0.5%) combined with epidural lidocaine (2%). We attempted to interrupt somatosensory pathways with spinal anesthesia but to avoid acute high thoracic sympathetic block. The visceral afferent pathways were to be blocked relatively slowly with epidural lidocaine. Eighty term parturients were randomly divided into four groups. In Group A, 2.5 mg of bupivacaine intrathecally combined with 22.2 +/- 4.6 mL of lidocaine epidurally provided insufficient muscle relaxation. In Group B, 5 mg of bupivacaine with 10.1 +/- 2.0 mL of lidocaine resulted in satisfactory anesthesia with rapid onset and minimum side effects. Anesthesia in Group C (7.5 mg of bupivacaine) and Group D (10 mg of bupivacaine) was mostly due to spinal block. Complications included hypotension, nausea, and dyspnea. The combined spinal/epidural technique, using 5 mg of bupivacaine and with sufficient epidural lidocaine to reach a T4 level, had the advantages of both spinal and epidural anesthesia with few of the complications of either.

Hemodynamic responses to surgical stimuli in brain-death organ donors.

Though spinal reflexes have been described in experimental brain-death animals, no documentation has been previously provided for human. The hemodynamic responses to surgical stimuli have been investigated here in eight brain-death organ donors. Baseline systolic blood pressure, diastolic blood pressure, and heart rate in observed patients were 99 +/- 15 mmHg, 61 +/- 13 mmHg, and 105 +/- 22 beats/min respectively. After skin incision, these parameters elevated maximally to 130 +/- 23 mmHg, 74 +/- 17 mmHg, and 119 +/- 18 beats/min (p < 0.05). Either spinal reflex arcs or adrenal medullary stimulation, or both, have been speculated to possibly play the role in these hemodynamic responses. However, the existence of such responses should not invalidate the diagnosis of brain death.

[Comparison of intravenous alfentanil, fentanyl and epidural lidocaine for extracorporeal shock wave lithotripsy].

Due to the development of newer generation of lithotriptor, the anesthesia for extracorporeal shock wave lithotripsy (ESWL) was variable recently. To compare opioid analgesia with epidural lidocaine for their efficacy in pain control, hemodynamic changes, side effects and patient acceptance during ESWL, sixty unpremedicated patients undergoing elective ESWL for upper urinary calculi with second generation Dornier MFL 5000 nonimmersion lithotriptor were randomly assigned equally into one of the following managements: Group E: 1% epidural lidocaine with 1:200000 epinephrine; Group A: 15 micrograms/kg alfentanil initially and 7 micrograms/kg on demand intravenously; Group F: 4 micrograms/kg fentanyl initially and 2 micrograms/kg on demand intravenously. Significant hypotension and bradycardia occurred in Gp.E as compared to baseline value (p < 0.05). Early respiratory depression was observed in both Gp. A and Gp. F, but Gp. A showed significantly shorter period (2 to 5 minutes) as compared to Gp.F (2 to 15 minutes). Under the insufflation of oxygen by nasal cannula, mean PaCO2 increased maximally to 50 mmHg, but no arterial oxygen desaturation (< 90%) was noted in Gp.A and Gp.F. The incidence of post-ESWL nausea was higher in Gp.F (p < 0.05), shivering and delayed recovery time were the main disturbing problems in Gp.E (p < 0.01). Although five-point verbal pain scale was significantly higher in Gp.A and Gp.F (at 30 to 45 minutes during ESWL) as compared to Gp.E, acceptance among patients was high throughout the course. We conclude that different anesthetic plans should be determined on different lithotriptors settings and patient's physical condition.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of hypothermia during abdominal surgery: comparison of thermal tube and blanket.

Twenty patients who received elective abdominal surgery for more than two hours were randomly assigned into two groups. Group 1 was warmed by using "EXACON" thermal therapy system model TT8200. Group 2 was warmed by using a thermal blanket of aquamatic K-thermia (electronic control), model PK-600 of American Hamilton medical systems. Other variables were kept constant, and the theater temperature was maintained at 24 degrees C. Core temperature was recorded every five minutes in a two hour period. There were statistically significant differences between these two groups intra-operatively. Decrease of temperature between these two groups had significant changes from 30 minutes to 2 hours (p less than 0.05). The warming effect of esophageal thermal tube was well controlled by directly warming the central compartment. However, the effect of blanket was unpredictable due to wet dressing and superficial warming of surgical fields. There were no side effects during the study.

Comparison of the combined effects of atropine and neostigmine with atropine and edrophonium on the occurrence of postoperative nausea and vomiting.

To investigate the effects of different types of anticholinesterase on the incidence of the postoperative nausea and vomiting, 100 ASA class I-II adult premenopausal female patients undergoing elective lower abdominal surgery were randomized into two groups. In both groups, anesthesia was induced with thiopental and fentanyl and 50% nitrous oxide and 0.5-1.5% of isoflurane were used for anesthetic maintenance with succinylcholine 1 approximately 1.5 mg/kg for intubation and atracurium 0.3 mg/kg/hr for maintenance of muscle relaxation. Patients received reversal agents for neuromuscular blockade after operation when the evoked train-of-four (TOF) count returned to four visual responses. A mixture of atropine 8 micrograms/kg and edrophonium 0.75 mg/kg was given to the first group of patients while atropine 15 micrograms/kg and neostigmine 40 micrograms/kg was given to another group of patients. All the patients were observed for the occurrence of nausea or vomiting for 2 hours after the operation in the recovery room. The incidence of nausea was not statistically significantly different in both groups (20% in neostigmine group and 26% in edrophonium group). The occurrence of vomiting was also similar in both groups (8% in neostigmine group and 6% in edrophonium group). We concluded that there were no difference in the incidence of postoperative nausea or vomiting with the use of either neostigmine or edrophonium with atropine for antagonizing neuromuscular blockade after the lower abdominal surgery.

The effect of total intravenous propofol on spontaneous respiration during anesthesia for minor surgery.

To evaluate adequate anesthetic depth without unacceptable respiratory consequences during total propofol intravascular anesthesia without intubation, the respiratory response was studied in 20 healthy patients (ASA class I or II), aged 20-50, premedicated with fentanyl 2 micrograms/kg. Anesthesia was induced in all patients with propofol 2.5 mg/kg, subsequently maintained by continuous propofol infusion at 12 mg/kg/h. An additional bolus of 20-60 mg propofol was given when anesthesia was considered inadequately. Assisted ventilation with 100% oxygen through a face mask was applied when apnea time was longer than 60 s. The mask was removed when patients regained spontaneous breathing. During induction stage, 7 patients developed apnea which required ventilatory support, although the period of apnea was short. Among them four regained spontaneous breathing within 5 min, and three within 10 min. PaCO2 significantly increased at both 10 min and 20 min after induction as compared with those before induction (p less than 0.05), while the change between 10 min and 20 min after induction was not statistically different. PaO2 showed little change and also it was not statistically significant. During maintenance of anesthesia spontaneous ventilation was stable and adequate. Though mild hypercapnia was noted, no medication was necessary. There was no episode of arterial oxygen desaturation throughout the course of maintenance. All patients could be adequately anesthetized except for six patients who required additional dose for insufficient anesthetic depth. No major adverse reactions occurred during or after induction. We concluded that the respiratory effect of propofol in total intravenous anesthesia could be divided into two stages: the induction stage and the maintenance stage.(ABSTRACT TRUNCATED AT 250 WORDS)