Biomedical subjects

H van Beem

Publications and source records attributed to H van Beem.

4 recordsLinked to original sources

PubMed1998

Long-term postoperative cognitive dysfunction in the elderly ISPOCD1 study. ISPOCD investigators. International Study of Post-Operative Cognitive Dysfunction.

BACKGROUND: Long-term postoperative cognitive dysfunction may occur in the elderly. Age may be a risk factor and hypoxaemia and arterial hypotension causative factors. We investigated these hypotheses in an international multicentre study. METHODS: 1218 patients aged at least 60 years completed neuropsychological tests before and 1 week and 3 months after major non-cardiac surgery. We measured oxygen saturation by continuous pulse oximetry before surgery and throughout the day of and the first 3 nights after surgery. We recorded blood pressure every 3 min by oscillometry during the operation and every 15-30 min for the rest of that day and night. We identified postoperative cognitive dysfunction with neuropsychological tests compared with controls recruited from the UK (n=176) and the same countries as study centres (n=145). FINDINGS: Postoperative cognitive dysfunction was present in 266 (25.8% [95% CI 23.1-28.5]) of patients 1 week after surgery and in 94 (9.9% [8.1-12.0]) 3 months after surgery, compared with 3.4% and 2.8%, respectively, of UK controls (p<0.0001 and p=0.0037, respectively). Increasing age and duration of anaesthesia, little education, a second operation, postoperative infections, and respiratory complications were risk factors for early postoperative cognitive dysfunction, but only age was a risk factor for late postoperative cognitive dysfunction. Hypoxaemia and hypotension were not significant risk factors at any time. INTERPRETATION: Our findings have implications for studies of the causes of cognitive decline and, in clinical practice, for the information given to patients before surgery.

Abdomen↗

PubMed1992

Spinal monitoring during vertebral column surgery under continuous alfentanil infusion.

An anaesthetic technique for surgical procedures on the vertebral column is described consisting of a continuous infusion of a short acting opioid, alfentanil, and a muscle relaxant, vecuronium, in combination with positive pressure ventilation using a nitrous oxide/oxygen mixture. It is shown that the two standard forms of spinal monitoring, wake-up testing and somatosensory cortical evoked potentials, can be employed effectively using this anaesthetic technique. Wake-up testing was performed in 23 patients. Average wake-up time was 10 min (SD 3.7 min). Evoked responses suitable for spinal monitoring could be obtained in 60 of 61 patients.

Adolescent↗

PubMed1983

Etomidate anaesthesia in patients with cirrhosis of the liver: pharmacokinetic data.

Five patients undergoing endoscopic injection of oesophageal varices were anaesthetised with etomidate 0.2 mg/kg followed by an infusion at a rate of 20 micrograms/kg/minute. Fentanyl 100-200 micrograms was also given intravenously and the patients' lungs were ventilated with oxygen in air. The postinfusion plasma etomidate concentration was described by a three compartment model with a mean half-life of 540 minutes (SEM 66.9) and volume of distribution of 8.9 litres/kg (SEM 0.6). Clearance was 12.7 ml/kg/minute (SEM 2.3). Compared to results in the literature obtained from normal patients, these cirrhotic patients had normal clearance rates, but the distribution volume and elimination half-life were twice as great. This suggests that cirrhotic patients metabolise etomidate normally, but the volume of distribution is doubled, thus resulting in prolonged elimination half-lives.

Anesthesia, General↗

PubMed1982

Nitrous oxide influences pattern EP estimate of visual acuity.

The effect of nitrous oxide (N2O) inhalation on the pattern EP with the onset and disappearance of checkerboard patterns was studied in four healthy volunteers. Checkerboards with checks ranging from 2 to 55 min of arc were presented to subjects sedated at various levels. Under the highest level introduced, 60% N2O, fixation of the pattern was still adequate. The major consistent changes in the pattern onset EP under N2O inhalation are (a) preferential attenuation of the response to small checks and (b) an increase of the response amplitude to large checks. The change in the amplitude versus check-size curve under N2O inhalation restricts the assessment of visual acuity on the basis of the pattern EP. In patients sedated with N2O, EP methods can be used only as a gross indicant of visual acuity.

Administration, Intranasal↗