[Cognitive impairment in the early postoperative period after remifentanil-propofol and sevoflurane-fentanyl anesthesia]

OBJECTIVE

In ambulatory anaesthesia the time required to recover from cognitive impairment should be as short as possible. The aim of this study was to compare the early cognitive recovery after remifentanil/propofol (R/P) and sevoflurane/fentanyl (S/F) anaesthesia.

METHODS

Sixty patients scheduled for elective gynaecological laparoscopy and 24 female volunteers tested for the assessment of learning effects were investigated. After praemedication with midazolam anaesthesia was induced with propofol, atracurium and either 1 microgram/kg fentanyl or 1 microgram/kg remifentanil. For maintenance 0.25 microgram/kg/min remifentanil and 0.6 mg/kg/min propofol (R/P) or 1.7 vol% sevoflurane (S/F) were given. Both groups were ventilated with 30% oxygen in air and received metamizol for postoperative analgesia. Verbal Learning Test, Stroop Colour and Word Interference Test, Digit Symbol Substitution Test and Four Boxes Test were performed the day before surgery and 30 min, 1 h, 2 h and 4 h after termination of anaesthesia.

RESULTS

For remifentanil/propofol cognitive function was still impaired 2 h (Verbal Learning) and 4 h (Stroop, Digit Symbol Substitution and Four Boxes Test) after termination of anaesthesia. After sevoflurane/fentanyl anaesthesia cognitive impairment lasted the same duration in Four Boxes Test, but shorter in Stroop and Digit Symbol Substitution and could not be found in Verbal Learning Test.

CONCLUSION

The duration of cognitive impairment in the early postoperative period differed by the test procedures and the anaesthetic procedures used in this investigation. Recovery appeared to be faster after sevoflurane/fentanyl than after remifentanil/propofol at least in aspects of cognitive function.

[Postoperative cognition disorders in elderly patients. The results of the "International Study of Postoperative Cognitive Dysfunction" ISPOCD 1)]

OBJECTIVE

Cognitive dysfunction is a known problem after operations and may be especially relevant in the elderly. The aim of this international multicentre study was to investigate short- and long-term cognitive dysfunction in elderly patients and to elucidate the relevance of hypoxaemia and hypotension as causative factors.

METHODS

1218 patients aged 60 years and older and scheduled for major non-cardiac surgery under general anaesthesia were investigated. Oxygen saturation was measured by continuous pulse oximetry before surgery and throughout the day of and the first 3 nights after surgery. Blood pressure was recorded every 3 minutes during the operation and every 15-30 min for the rest of that day and night. Cognitive testing was performed before and 1 week and 3 months after the operation. Cognitive dysfunction was identified with neuropsychological tests compared with controls recruited from the UK (n = 176) and the same countries as study centres (n = 145).

RESULTS

Postoperative cognitive dysfunction was present in 25.8% of patients 1 week after surgery and in 9.9% 3 months after surgery, compared with 3.4% and 2.8%, respectively, of the UK controls. Increasing age and duration of anaesthesia, little education, a second operation, postoperative infections, and respiratory complications were the risk factors for early postoperative cognitive dysfunction, but only age was a risk factor for long-term postoperative cognitive dysfunction. Hypoxaemia and hypotension were not significant risk factors at any time.

CONCLUSION

With this investigation long-term cognitive dysfunction could be proven definitively for elderly patients after major operations under general anaesthesia. No factors with prophylactic or therapeutic influence were detectable so that aetiology and pathophysiology of POCD could not be further determined.

[Bioavailability of sotalol in short bowel syndrome]

BACKGROUND

The individual bioavailability of enterally administered drugs is usually uncertain in case of reduced bowel length. Routine measurements of plasma concentrations are available only for a small number of drugs. The daily dose recommended by the manufacturers may result in subtherapeutic plasma concentrations when given to such patients.

CASE REPORT

In 2 patients with hemodynamically relevant atrial fibrillation and reduced gut length application of increasing sotalol doses was initiated. For the assessment of the individual bioavailability plasma concentrations were measured via HPLC immediately before and 2 hours after enteral application of sotalol. Judging by clinical criteria both patients were treated successfully. Even in the patient with severe short bowel syndrome (stomach, duodenum and 50 cm jejunal remnant) doubling of the daily dose led to a substantial increase in plasma concentrations.

CONCLUSION

Effective enteral medication with sotalol in patients with short residual bowel is possible. Normal plasma concentrations can be achieved by administering doses according to the manufacturers' instructions. In case of severe short bowel syndrome, the measurements of plasma concentrations may be beneficial in supervising dose-adjustment.

[TIVA with propofol-remifentanil or balanced anesthesia with sevoflurane-fentanyl in laparoscopic operations. Hemodynamics, awakening and adverse effects]

OBJECTIVE

This study was designed to investigate the differences between TIVA with propofol/remifentanil (P/R) and balanced anaesthesia with sevoflurane/fentanyl (S/F) in gynaecological laparoscopic surgery. Emphasis was put on haemodynamic reaction, recovery profile, postoperative side effects and patient satisfaction.

METHODS

Sixty patients were randomly assigned to receive either total intravenous anaesthesia with propofol/remifentanil or anaesthesia with sevoflurane/fentanyl. After premedication (midazolam) and induction of anesthesia (propofol, atracurium) in both groups, either 1 microgram/kg fentanyl (S/F) or 1 microgram/kg remifentanil (P/R) was injected. Anaesthesia was maintained with 0.5 microgram/kg/min remifentanil (reduced to 50% after 5 min) and 0.06 microgram/kg/min propofol (P/R) or 1.7 vol % sevoflurane (S/F). Both groups were mechanically ventilated with 30% oxygen in air. The administration of sevoflurane and the infusion of the anaesthetics were adjusted to maintain a surgical depth of anaesthesia. For postoperative analgesia 1 g paracetamol was administered rectally prior to surgery. After recovery 20 mg/kg metamizol was given intravenously. At the end of surgery the anaesthetics were discontinued and haemodynamics, early emergence from anaesthesia, pain level, frequency of analgesic demand, incidence of PONV, shivering and patient satisfaction were assessed. Parameters were recorded for 24 h postoperatively.

RESULTS

Recovery time after propofol-remifentanil anaesthesia was significantly shorter than after administration of sevoflurane and fentanyl (spontaneous ventilation 4.1 vs. 6.3 min, extubation 4.3 vs. 9.3 min, eye opening 4.4 vs 8.2 min, stating name 5.3 vs. 13.2 min, stating date of birth 5.4 vs. 13.3 min). There were no significant differences between the groups in shivering, pain score, analgesic demand and PONV. The S/F group responded to tracheal intubation with significantly higher blood pressure than the P/R group. During maintenance of anaesthesia heart rate in patients with S/F was significantly higher (P/R:HR max +16/-10; S/F:HR max +24/-0.). Measured on a scale (S/F 62%).

CONCLUSION

Compared with patients given balanced anaesthesia with sevoflurane and fentanyl, TIVA with propofol and remifentanil proved to be particularly suited for gynaecological laparoscopic surgery. Its major advantages are haemodynamic stability, significantly shorter times of emergence, and the exceptional acceptance by the patients.

[Comparative study of pethidine and clonidine for prevention of postoperative shivering. A prospective, randomized, placebo-controlled double-blind study]

OBJECTIVE

Patients with ischaemic heart disease and cardiac failure are endangered by an increase in oxygen consumption caused by postoperative shivering. The purpose of this study was to evaluate if pethidine and clonidine, which are well known for their effectiveness in the treatment of this undesirable side effect, can also prevent postoperative shivering if administered at the end of surgery. In addition it was investigated whether their intraoperative application influences the time of extubation and analgesics demand in the early postoperative period.

METHODS

60 patients (ASA I-II) scheduled for elective microsurgical vertebral disc resection were included in the study. After standardised induction of anaesthesia (5 mg x kg-1 thiopental, 2 micrograms x kg-1 fentanyl, 0.1 mg x kg-1 vecuronium) lungs were ventilated with isoflurane vaporized in 66% N2O and 33% O2. The concentration of the inhalation anaesthetic was adjusted to maintain a surgical plane of anaesthesia without supplementary doses of opioids. Patients were randomly allocated in a double-blind fashion to one of three groups (each n = 20) to receive either pethidine (0.3 mg x kg-1) or clonidine (2 micrograms x kg-1) or 0.9% saline (control) 5 minutes prior to the end of surgery. Heart rate, arterial blood pressure and rectal temperature were measured at defined times, as well as the recovery time between the end of anaesthesia and extubation, incidence of postoperative shivering, and the pain level of the patients with a visual analog scale. The frequency and total demand of analgesics were determined using patient controlled analgesia and recorded for two hours postoperatively.

RESULTS

The incidence of postoperative shivering in the clonidine group (5%) was less than in the pethidine group (25%) and significantly less than in the saline group (55%). Heart rate and blood pressure values after the administration of clonidine were lower than after pethidine and significantly lower than after saline. The time between end of surgery and extubation was similar in all groups with an average of 18 minutes. No significant differences among the pain scores and the analgesics demand were noted among any of the groups, including the saline control-group.

CONCLUSION

Intraoperative administration of clonidine (2 micrograms x kg-1) is suitable for prevention of postoperative shivering. Despite its sedative effects the recovery time until extubation was not prolonged. 0.3 mg x kg-1 pethidine proved to be less beneficial.