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Biomedical subjects

P S Sebel

Publications and source records attributed to P S Sebel.

At least 73 records · Page 4Linked to original sources
PubMed1985

A comparison between isoflurane and alfentanil supplemented anaesthesia for short procedures.

Sixty unpremedicated patients undergoing short urological and gynaecological procedures were randomly allocated to three groups to receive either methohexitone, alfentanil, nitrous oxide and oxygen, methohexitone, isoflurane and oxygen or methohexitone, isoflurane, nitrous oxide and oxygen. The group receiving methohexitone, isoflurane and oxygen was abandoned after 11 patients had been studied, due to poor conditions during induction of anaesthesia. Therefore, data from only 51 patients are presented. Early recovery was assessed by time to opening eyes, giving correct name and date of birth; later, recovery was assessed by using the postbox test and deletion of 'p's. During anaesthesia and surgery, there was a high incidence of coughing and laryngospasm in the isoflurane groups. The patients in the alfentanil group opened their eyes and gave their names and dates of birth significantly faster postoperatively (p less than 0.01) than those in the isoflurane groups. However, there were no significant differences between the three groups regarding the later tests of recovery. The late recovery after isoflurane was equal to that obtained using an intravenous technique with alfentanil, although the peroperative complication rate was higher.

Adjuvants, Anesthesia↗
PubMed1985

The neuromuscular transmission monitor. A clinical assessment and comparison with a force transducer.

The neuromuscular transmission monitor (NTM) is a new device for measuring neuromuscular transmission during anaesthesia. We have assessed its use in comparison with a force transducer and found for single twitch and train-of-four modes that there was a strong positive correlation between the two methods. This device appears reliable in use and provides a satisfactory alternative to conventional neuromuscular monitoring.

Alcuronium↗
PubMed1985

Endocrinological effects of intrathecal morphine.

This study was designed to evaluate the metabolic effects of intrathecal morphine in patients undergoing coronary artery surgery. Ten patients received 4 mg preservative-free morphine in 6 ml saline intrathecally before surgery and were compared with 10 patients anaesthetised in a similar manner, though without intrathecal morphine. Catecholamines, cortisol and glucose measurements were made during surgery and for 24 h post-operatively. The control group had a higher post-operative requirement for papaveretum, indicating that intrathecal morphine provided some post-operative analgesia. In the period from end of surgery to 5 h after surgery, cortisol secretion was suppressed in the intrathecal morphine group.

Adult↗
PubMed1985

A comparison of the haemodynamic effects of propofol ('Diprivan') and thiopentone in patients with coronary artery disease.

Twenty patients scheduled for elective coronary surgery received either propofol ('Diprivan') 1.5 mg/kg in emulsion or thiopentone 2 mg/kg for induction of anaesthesia. Vecuronium was used for neuromuscular blockade. Cardiovascular dynamics were recorded every minute until 6 min after intubation. Anaesthesia with propofol was accompanied by a reduction in arterial pressure, the decrease being severe in two patients. This was largely due to a decrease in systemic vascular resistance. Thiopentone anaesthesia resulted in a smaller decrease in arterial pressure, but a marked increase in arterial pressure followed endotracheal intubation. Although the absence of haemodynamic changes following intubation during propofol anaesthesia is advantageous to the ischaemic myocardium, this has to be balanced by the variable and sometimes severe reduction in arterial pressure that occurred on induction.

Anesthesia, Intravenous↗
PubMed1984

Effect of nitrous oxide on visual, auditory and somatosensory evoked potentials.

The effects of 10%, 30% and 50% nitrous oxide on visual, auditory and somatosensory evoked potentials were studied in seven healthy volunteers. The evoked potentials were averaged from the electroencephalogram following repeated peripheral sensory stimulation of the appropriate modality. Latencies and amplitudes of the resulting potentials were measured and compared with control values. In five subjects, increasing concentrations of nitrous oxide were associated with a graded reduction in amplitude of the visual (P less than 0.02) and somatosensory (P less than 0.02) evoked potentials. The latency of the first major negative potential of the visual evoked potential was significantly increased (P less than 0.02). Latencies of brainstem auditory evoked potentials did not alter. In the other two subjects the amplitudes of the visual and somatosensory evoked potentials showed graded increase with decreasing concentrations of nitrous oxide, confirming that the changes are dose related. As nitrous oxide is used almost universally during anaesthesia, these changes must be taken into account when assessing variations observed during operation in anaesthetic-related evoked potential studies.

Adult↗
PubMed1984

Alfentanil-supplemented anaesthesia for short procedures. A double-blind comparison with fentanyl.

Eighty unpremedicated female patients undergoing short gynaecological procedures were randomly allocated to four groups and received either alfentanil or fentanyl (double-blind), together with Althesin-oxygen or methohexitone-nitrous oxide'-oxygen. Recovery from anaesthesia was assessed using the post-box test and the deletion of p. There was a significantly greater frequency of vomiting after operation (P less than 0.05) with methohexitone compared with Althesin and with fentanyl compared with alfentanil, and a significantly greater frequency of pain on injection (P less than 0.001) with methohexitone compared with Althesin. The alfentanil groups completed the post-box test significantly earlier after operation than the fentanyl groups (P less than 0.05). We conclude that alfentanil may offer a significant advantage over fentanyl as an analgesic supplement to i.v. anaesthesia for short procedures.

Adjuvants, Anesthesia↗
PubMed1984

The pharmacokinetics of sufentanil in surgical patients.

The pharmacokinetics of sufentanil, a new thienyl analogue of fentanyl, were studied in 10 surgical patients. Sufentanil, 5 micrograms/kg, was given intravenously as a bolus injection and plasma concentrations measured at intervals up to 8 h. Plasma sufentanil concentrations decreased rapidly after injection--98% of the administered dose having left the plasma within 30 min. In 9 of the 10 patients, a tri-exponential equation optimally described the sufentanil concentration decay curve, with average (+/-SEM) half-lives for the rapid (pi) and slow (alpha) distribution phases of 1.4 +/- 0.3 min and 17.7 +/- 2.6 min, respectively. The average terminal elimination (beta) half-life was 164 +/- 22 min. The average value for Vd beta was 2.9 +/- 0.2 1/kg, Vdss 1.7 +/- 0.2 1/kg and total plasma clearance 12.7 +/- 0.8 ml X kg-1 X min-1 (935 +/- 50 ml/min). In one patient, a bi-exponential equation was sufficient to describe the concentration-time data, yielding a distribution half-life of 4.7 min and an elimination half-life of 117 min.

Adult↗
PubMed1984

The effect of nitrous oxide on cerebral electrical activity.

Recordings of cerebral electrical activity produced by the cerebral function analysing monitor ( CFAM ) were obtained from nine healthy volunteers breathing increasing concentrations of N2O in O2. Concentrations of 30 and 50% N2O produced significant reductions in CFAM trace amplitude. Withdrawal of N2O resulted in an increase in amplitude with an initial increase above the control level. There were no consistent changes in the frequency distribution of the weighted electroencephalographic signal with increasing concentrations of N2O.

Adult↗
PubMed1984

Electroencephalographic effects of fentanyl-, sufentanil- and alfentanil anaesthesia in man.

EEGs taken from patients during and following open heart surgery were analyzed by computer. Patients were treated with high doses of either fentanyl, sufentanil or alfentanil as the sole anaesthetic. The aims were to determine depth of anaesthesia, comparing different doses of one compound and comparing different narcotics. Further, recovery from anaesthesia was also studied using EEG criteria.

Alfentanil↗
PubMed1984

Opioid analgesics in anesthesia: with special reference to their use in cardiovascular anesthesia.

In this article, an attempt has been made to review the use of receptor stimulating pure agonist opioids in anesthesia, especially in patients with cardiovascular disease. Particular emphasis has been placed on the use of opioids in high doses to produce anesthesia, techniques that recently have become popular in cardiovascular anesthesia. A major benefit of opioid anesthesia is the cardiovascular stability obtained during induction and throughout operation, even in patients with severely impaired cardiac function. There is a considerable body of evidence to support this claim when fentanyl is used. Anesthetic doses of morphine are associated with a higher incidence of cardiovascular disturbances and other problems, and, therefore, more attention to detail is required in order to achieve adequate anesthesia and hemodynamic stability. Although other opioids have been used as sole or principal agents in anesthesia for cardiovascular surgery, none have gained widespread acceptance. Meperidine, for example, which is widely used in lower (nonanesthetic) doses as a supplement to nitrous oxide in cardiac and noncardiac surgery, has proved unsuitable because of severe hemodynamic disturbances when high doses are given. However, initial reports concerning two of the newer agonist opioids, sufentanil and alfentanil, suggest that they may prove to be suitable alternatives and perhaps provide advantages over morphine and fentanyl in patients with or without cardiovascular disease. Although cardiovascular stability usually can be assured in the chronically sick cardiac patient with opioid anesthesia, this is not always so with the healthier patient, particularly those presenting for coronary artery surgery. A frequently occurring problem in these patients is hypertension during or after sternotomy, which can result in myocardial ischemia and infarction. The incidence of severe hypertension (increases in systolic blood pressure greater than 20% of control values) can be reduced drastically by increasing the dose of opioid, e.g., up to 140 micrograms/kg of fentanyl. However, despite such large doses, some patients will continue to need treatment with vasodilators, inhalation anesthetics, or other supplements at certain periods during cardiovascular operations. The use of very large doses of opioids also will prolong postoperative respiratory depression. High doses of opioids can reduce or prevent the hormonal and metabolic responses to the stress of surgery. However, even very large doses of fentanyl or its newer analogues do not prevent marked increases in plasma catecholamine concentrations in response to cardiopulmonary bypass.(ABSTRACT TRUNCATED AT 400 WORDS)

Alfentanil↗
PubMed1983

The cerebral function analysing monitor (CFAM). A new microprocessor-based device for the on-line analysis of the EEG and evoked potentials.

A description is given of a new microprocessor-based device for EEG analysis. The Cerebral Function Analysing Monitor (CFAM) analyses the EEG amplitude and frequency distribution. It produces a detailed plot of amplitude trends and separate traces of the percentage activity in each of the classical EEG frequency bands. Its clinical application was studied in five patients anaesthetized with thiopentone, and nitrous oxide and halothane in oxygen. During maintenance of anaesthesia, there was a gradual decrease in EEG amplitude and shift towards lower frequency EEG activity. Discontinuation of nitrous oxide resulted in a marked increase in EEG amplitude and an increase in alpha and beta band activity. Discontinuation of halothane resulted in smaller alterations in the CFAM trace. This device provides easily interpreted processed EEG data and merits further investigation.

Adult↗
PubMed1983

Influence of high-dose alfentanil anaesthesia on the electroencephalogram: correlation with plasma concentrations.

The influence of high-dose alfentanil-oxygen-air anaesthesia on the electroencephalogram was studied in 10 patients undergoing elective coronary artery surgery. Premedication was either lorazepam 5 mg orally (n = 5) or morphine 10 mg and hyoscine 0.4 mg i.m. (n = 5). Anaesthesia was induced with alfentanil 125 micrograms kg-1 h-1 and maintained by a continuous infusion at a rate of 0.25-0.5 mg kg-1. The EEG was recorded on the day before surgery, continuously from before induction of anaesthesia until the end of surgery and at hourly intervals after operation. Blood samples were withdrawn at intervals during and after surgery for measurement of plasma alfentanil concentrations. Anaesthesia was associated with large increases in delta activity and reduction in higher frequency components. There was less synchronization of the EEG than is observed with fentanyl or sufentanil. Spindle activity was prominent in 70% of patients. The changes in the EEG during recovery tended to occur abruptly and there was no obvious correlation between the EEG and plasma concentrations of alfentanil. There was a significant correlation between the total dose of alfentanil and the awake plasma concentration (r = 0.94; P less than 0.01). Plasma concentrations decreased exponentially after operation, with a mean half-life of 304 +/- 54 min.

Alfentanil↗
PubMed1982

Electroencephalographic effects of sufentanil anaesthesia in man.

The effects of anaesthesia with sufentanil 15 micrograms kg-1, air and oxygen on the electroencephalograph were studied in 12 patients before and after cardiopulmonary bypass. The e.e.g. responses were characterized by high voltage, slow delta waves. Although the mean power in the delta band declined with time, the contribution of delta power to total power in the frequency range 0.5-40 Hz remained constant until the onset of cardiopulmonary bypass. Sharp waves of uncertain neurophysiological significance were seen. They were not associated with clinical signs of epileptic activity. The use of the e.e.g. response as a monitor of "depth of anaesthesia" during high-dose opioid anaesthesia may become possible.

Anesthesia, Intravenous↗