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PubMed1999

Cost analysis of target-controlled infusion-based anesthesia compared with standard anesthesia regimens.

UNLABELLED: With the development of new computer-assisted target-controlled infusion (TCI) systems and the availability of short-acting anesthetics, total IV anesthesia (TIVA) has become increasingly popular. The aim of this study was to compare costs of TCI-based anesthesia with two standard anesthesia regimens. Sixty patients undergoing elective laparoscopic cholecystectomy were randomly divided into three groups. Group 1 (TIVA/TCI) received TIVA using a propofol-based TCI system and continuous administration of remifentanil; Group 2 (isoflurane) underwent inhaled anesthesia with isoflurane, fentanyl, and N2O; Group 3 (standard propofol) received fentanyl and N2O and a continuous infusion of propofol using a standard delivery system. Maintenance doses for anesthetics were adjusted according to the patient's need. Isoflurane consumption was measured by weighing the vaporizer by using a precision weighing machine. Duration of surgery and of anesthesia was similar in the three groups. Time from stopping administration of anesthetics until tracheal extubation (6+/-2 min) and stay in the postanesthesia care unit (PACU; 70+/-12 min) were shorter in Group 1 than in the Groups 2 (15+/-3 and 87+/-13 min, respectively) and 3 (10+/-4 and 81+/-14 min, respectively) (P < 0.05). Episodes of postoperative nausea and vomiting in the PACU and on the surgical ward were less common in Group 1 than in the other two groups. Intraoperative costs were higher in Group 1 ($62.19/patient; $0.55/min of anesthesia) than in Groups 2 ($16.97/patient; $0.13/min of anesthesia) and 3 ($34.68/patient; $0.32/min of anesthesia). Cost for discarded anesthetic drugs accounted for almost 18% of total intraoperative costs in Group 1. We conclude that TIVA/TCI anesthesia using propofol/remifentanil was associated with the highest intraoperative costs but the fewest postoperative side effects. An overall cost-effectiveness analysis of new anesthetic regimens must balance the direct cost of anesthetics and beneficial effects leading to improved patients' comfort. IMPLICATIONS: In today's climate of cost-consciousness, careful economic evaluation of new anesthetic regimens is necessary. A target-controlled infusion (TCI)-based total IV anesthesia (TIVA) regimen using propofol and remifentanil was compared with a standard propofol anesthesia regimen and an inhaled anesthetic technique using isoflurane. Target-controlled infusion/total IV anesthesia was associated with the largest intraoperative costs but allowed the most rapid recovery from anesthesia, was associated with fewest postoperative side effects, and permitted earlier discharge from the postanesthesia care unit.

Adult↗
PubMed1995

Rapid inhalation induction of anesthesia by halothane, enflurane, isoflurane and sevoflurane and their cardiopulmonary effects in dogs.

The rapid inhalation induction of anesthesia (RII) by mask inhalation of halothane, enflurane, isoflurane and sevoflurane at an equianesthetic concentration (2.5 MAC) was evaluated in 24 beagle dogs. The differences in movements, induction and intubation time between anesthetics were mainly associated with the differences in each blood/gas solubility. The most rapid and smoothest induction was observed by sevoflurane inhalation (209.0 +/- 44.2 sec), followed by isoflurane inhalation (285.8 +/- 34.1 sec). Halothane inhalation took the longest induction time (790.3 +/- 75.7 sec). Movements during RII were minimal in sevoflurane group comparing to the other groups. Heart rate, cardiac output and rate pressure product significantly increased after the beginning of inhalation in all the dogs except for those of halothane group. These changes exceeded the physiological level just after the beginning of inhalation, however, rapidly reversed to the maintenance level (1.5 MAC) approximately 10 min after intubation. Consequently, sevoflurane seemed to be the best inhalational anesthetic for RII in dogs without significant problems in respiratory and/or cardiac functions. Isoflurane also induced rapid induction with some degree of the movements.

Analysis of Variance↗
PubMed2003

Different benefit of bispectal index (BIS) in desflurane and propofol anesthesia.

BACKGROUND: Bispectal index (BIS) monitoring may reduce drug usage and hasten recovery in propofol and inhalation anesthesia. The faster emergence profile of desflurane may reduce the effect of BIS monitoring on recovery from desflurane compared with propofol. This study compared hypnotic drug usage, recovery, patient satisfaction and incidence of inadequate sedation in BIS monitored and nonmonitored women anesthetized with desflurane or propofol. METHODS: One hundred and sixty patients scheduled for elective gynecological surgery were randomly assigned to desflurane or propofol anesthesia with and without BIS monitoring. Fentanyl, vecuronium and remifentanil were administered according to clinical criteria. The BIS monitor was used in all patients, but the monitor screen was covered in the controls. A BIS level between 45 and 55 was targeted in the BIS monitored patients whereas depth of anesthesia was assessed by clinical criteria in the controls. RESULTS: The mean (SD) desflurane MAC-hours administered with and without BIS were 0.70 (0.15) and 0.76 (0.12), respectively, resulting in extubation times of 6.5 (4.1) and 8.3 (6.1) min. (NS). Bispectal index monitoring was associated with improved patient satisfaction, reduced postoperative nausea and antiemetic drug requirement, and fewer episodes with sustained BIS levels > 60. The mean (SD) propofol infusion rates were 6.0 (1.4) and 6.6 (0.9) mg kg(-1)h(-1) with and without the BIS monitor (P = 0.023), resulting in mean (SD) extubation times of 6.8 (4.6) and 10.5 min (5.9), respectively (P < 0.05). CONCLUSION: Bispectal index monitoring reduced propofol usage and hastened recovery after propofol anesthesia, whereas in desflurane anesthesia it was associated with improved patient satisfaction, probably because of decreased postoperative nausea and fewer episodes of inadequate hypnosis.

Adult↗
PubMed1987

[The pharmacokinetics of midazolam in various kinds of anesthesia].

Several authors reported a decrease in metabolism of drugs during inhalational anesthesia. In this study we investigated the influence of several kinds of anesthesia on the metabolism of midazolam. Methods. In 43 patients who underwent minor surgery, anesthesia was induced by injecting 0.2 mg fentanyl followed by 0.15 mg/kg midazolam. Anesthesia was maintained by either halothane/nitrous oxide (group 1), isoflurane/nitrous oxide (group 2), fentanyl/droperidol/nitrous oxide (group 3), or halothane/air/oxygen (group 4). Venous blood was drawn after 5, 15, 30, 60, 90, 120, 180, 240, 300 and 360 min. Using the two-compartment model we estimated distribution half-life (t1/2a), elimination half-life (t1/2el), clearance (Cl), and volumes of distribution (Vz = volume in elimination phase). Results. There were no significant differences of elimination parameters between the four groups. Elimination half-life ranged from 0.72 to 15.06 h. Cl ranged from 2.5 to 12.8 ml/min per kilogram. Four patients (= 9%) had a t1/2el of 7-15 h; in 16 cases we found secondary concentration peaks. There was no correlation between drowsiness in the postoperative period and midazolam concentration. Conclusion. Even if anesthesia should influence the metabolism of midazolam, for example by reducing liver blood flow, we did not find any difference between the four groups. In accordance with others, we found some patients with a half-life of up to 15 h, which might reflect the influence of the anesthesia itself.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1997

Adsorption of inhalational anesthetics and hydrochlorofluorocarbons on activated carbons as a biological model.

Chlorofluorocarbon (CFC) replacements have recently been used for their lower stability and because they have carbon-hydrogen bonds, which means that their atmospheric lifetime is expected to be much shorter than those of CFCs. The adsorption properties of 1,1,2-trichloro-1,2,2-trifluoroethane (CFC113) and its replacement compounds, 1,1-dichloro-2,2,2-trifluoroethane (HCFC123), 1,1-dichloro-1-fluoroethane (HCFC141b), and 1,1-dichloro-1,2,2,3,3-pentafluoropropane (HCFC255ca) on four kinds of activated carbons were investigated. The amount of CFC and HCFCs adsorbed on the activated carbon was concluded to depend upon the number of chloride and carbon atoms in their molecules. The adsorption isotherms of inhalational anesthetics (halothane, chloroform, enflurane, isoflurane, and methoxyflurane) on the activated carbon were measured to evaluate the action mechanism of inhalational anesthesia. The adsorption isotherms of CFC, HCFC, and the inhalational anesthetics were fitted to the Freundlich equation. The Freundlich constant N was well correlated with the minimum alveolar concentration (MAC) of the inhalational anesthetic: 1 MAC means that 50% of the patients will not move during a surgical operation. The adsorption mechanism of inhalational anesthetics on the surface of the activated carbon is concluded to be similar to the adsorption mechanism on a nerve cell. The anesthesia of CFC replacements can be estimated by the Freundlich constant N of the adsorption isotherms.

Adsorption↗
PubMed1956

Trifluoroethylvinyl ether (fluoromar); a preliminary report on clinical experience and animal experiment.

In observations of 80 cases in which Fluoromar was used for inhalation anesthesia it was noted that induction was rapid; maintenance although labile, was usually smooth; and recovery of reflexes was rapid. Anesthetic complications were minimal, and postanesthetic complications were limited to nausea and vomiting in no greater incidence than that expected to follow the use of most inhalation anesthetic agents. Fluoromar produces rapid, and not particularly unpleasant, loss of consciousness, and will produce complete anesthesia without supplement. However, the muscular relaxation afforded by Fluoromar is not complete, and delayed recovery from anesthesia may follow attempts to produce relaxation by deepening too greatly the level of anesthesia. The inflammability of Fluoromar is less than that of other inhalation agents.

Analgesia↗
PubMed2003

[Anaesthesia for patients with intracranial hypertension due to cerebral oedema].

The main objective for anaesthesia in patients with intracranial hypertension (ICH) is to maintain the cerebral perfusion pressure (CPP). Before the operation, the assessment of the level of intracranial pressure relies on the Glasgow coma score and the signs of ICH on the CT-scan. In the perioperative period, repeated transcranial Doppler examinations may help in determining the adequate CPP. Haemodynamic and respiratory complications are common after subarachnoid haemorrhage or head injury. Careful preoperative screening of the cardiovascular and respiratory system is mandatory before anaesthesia. There is no recommended anaesthetic technique for patients with ICH. Nitrous oxide should be avoided in patients with severe ICH or during emergency surgery. Theoretically, intravenous anaesthesia is a better choice than inhalation anesthesia because of the cerebral vasodilatation induced by inhalation agents. In the most severe cases thiopental is the only anaesthetic agent to consider. Treatment of hypovolaemia with fluid loading and the early use of vasoactive agents can be recommended to maintain CPP. Before intracranial surgery, large doses of mannitol have been demonstrated to improve neurological recovery in brain injured patients. The urinary losses due to the infusion of mannitol should be replaced with isotonic saline. Emergence and extubation are best performed in the intensive care unit under close systemic and cerebral haemodynamic control.

Anesthesia↗
PubMed1999

[Quantification of postoperative vigilance by evoked potentials].

OBJECTIVE: Patients will be discharged from the postoperative recovery room mostly on subjective clinical assessment. In this study an approach to a more quantitative judgment of postoperative vigilance is made by recording the P300-latency and neuropsychological tests. METHODS: 22 adult patients undergoing a disc operation were examined. For induction of anesthesia thiopental (4-5 mg/kg), fentanyl (0.1 mg) and a musclerelaxant (atracurium 0.4 mg/kg or succinylcholine 1-2 mg/kg after precurarisation with atracurium 5 mg) were given. Anesthesia was then continued with enflurance (1.0-1.2 MAC) in a mixture of 67% nitrous oxide in oxygen. If postoperative analgesia was needed, piritramid was injected in boli à 3-6 mg. The P300 was acoustically stimulated with an oddball-paradigm and recorded at Fz and Cz. Afterwards the latencies were measured and compared with a vigilance score composed of clinical parameters and neuropsychological tests. Recordings were done preoperatively and every 30 minutes up to 2 hours postoperatively. A correlation between P300-latencies and vigilance score was made with the coefficient of Spearman. Comparison of pre- and postoperative values was managed by using Wilcoxon test for matched pairs with Bonferroni-correction. RESULTS: Immediately after operation, P300 was obtained only in 8 patients (36%). The latencies were delayed (394 +/- 35 ms versus 326 +/- 12 ms preoperatively). During follow-up patients recovered and 2 hours postoperatively only one patient had no P300. At the end of the examination period P300-latencies of most patients had not yet reached the preoperative levels. The vigilance score in parallel showed decreases immediately after the operation and increases later on. However there were discrepancies between P300 latencies and neuropsychological findings, in some cases possibly due to the sedative effects of postoperative analgetics. CONCLUSION: Recording of P300-latencies showed remarkable cognitive deficits because of subclinical anesthesia hangover even 2 hours after a routine inhalational anesthesia. It is a good quantifiable method for assessment of postoperative vigilance. In some cases P300-latency is a more sensitive parameter for vigilance phenomena than clinical and neuropsychological scores.

Adult↗
PubMed2003

One-stop surgery in pediatric surgery. Aspects of anesthesia. Preliminary report.

AIM: One-Stop Surgery (OSS) is a new day surgery combining preoperative evaluation and subsequent operation in one medical examination. METHODS: This paper reports the authors' initial experience using this method. Referring physicians were informed of the methods and selected surgical and anesthetic procedures by fax. They were also faxed a form to fill in with case history details and instructions to the parents on the preoperative fast. The completed form was faxed back to the surgeon and pediatric anesthetist who determined patient suitability and scheduled hospitalization and surgery. On hospitalization physical examination was performed to confirm diagnosis and rule out contraindications for anesthesia. Patients considered suitable then underwent surgery and were discharged on the same day as a day case. The families were given instructions to be followed for home care and emergency telephone numbers. In the time interval November 2000 to February 2001 43 patients aged between 2 and 7 years were treated following this procedure for removal of a central venous catheter (16 patients), umbilical (2 patients) and inguinal (10 patients) hernia repair, and prepuce dorsal slit (15 patients). Anesthesia consisted of nasal premedication using midazolan, general inhalation anesthesia and peripheral locoregional block. RESULTS: The diagnosis of all chidren was confirmed. Only 1 patient with upper airway infection was discovered. Recovery of all patients was uneventful. None of the patients called during the postoperative follow-up period for adverse events. CONCLUSIONS: Low costs and major parent and patient satisfaction are the main advantages of OSS, while the possible disadvantages are inaccurate referral for surgery and detection of contraindications for anesthesia at admittance to hospital. The authors recommend the use of wide scale OSS only when the operators have sound experience in pediatric day surgery.

Ambulatory Surgical Procedures↗