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Biomedical subjects

H Schaer

Publications and source records attributed to H Schaer.

At least 19 recordsLinked to original sources
PubMed1992

[Intrathecal morphine for postoperative pain].

At the beginning, the way intrathecal morphine was used for postoperative pain relief was quite unfortunate, because the doses derived from experience with morphine-tolerant cancer patients were considerably too high and respiratory depression occurred frequently. Subsequent dose-finding studies showed that the doses of morphine used initially could be reduced by a factor of ten without loss of the analgesic effect and with a marked reduction in side-effects. No respiratory depression has been reported when doses below 0.1 mg morphine are used. METHOD. In this prospective study the effect of 0.06 to 0.08 mg intrathecal morphine, mixed with the local anaesthetic for spinal anesthesia, was investigated in surgical patients aged 21 to 81 years, ASA grade I or II, scheduled for orthopaedic operations or herniorraphies. Thirty unpremedicated patients were enrolled in the study and were, after informed consent, randomly allocated to a control group without morphine or to a morphine group. The analgesic effect was assessed by the time interval between the administration of the spinal anaesthesia and the first demand for an analgesic medication. The mood state was evaluated with the adjective checklist of Janke and Debus 6 h after the spinal anaesthesia. RESULTS AND DISCUSSION. In the control group half of the patients asked for an analgesic medication within 275 min (median) after the spinal anaesthesia, and all patients within 420 min, whereas in the morphine group half of the patients asked for an analgesic within 1170 min (median). Seven patients had not required an analgesic at the termination of the observation period 20 h after the spinal anaesthesia. The mood status showed no difference between the two groups, in particular, no dizziness or drowsiness after morphine. There was no difference in the incidence of side-effects such as nausea or urinary retention between the two groups. Pruritus was not reported spontaneously but was found upon questioning in five patients. It was in no case disturbing. CONCLUSIONS. Morphine (0.06 to 0.08 mg) mixed with the local anaesthetic for spinal anaesthesia provided for an analgesia of more than 20 h duration in half of the patients. This technique is safe, simple, reliable and virtually free of side-effects. No particular supervision due to the administration of intrathecal morphine is necessary in this dose range if systemic opiates are avoided. If the analgesia is unsatisfactory, a non-opioid analgesic is recommended.

Adult↗
PubMed1990

[Antagonism of flunitrazepam and fentanyl by flumazenil, naloxone or nalbuphine].

The new benzodiazepine antagonist flumazenil represents another approach to the ever-present problem of recurring respiratory depression after anesthesia with flunitrazepam and fentanyl. Objective and subjective side effects of flumazenil were studied in comparison with the opiate antagonists naloxone and nalbuphine. METHODS. One hundred fifty surgical patients, ASA I or II, aged 18-65 years were studied. After premedication with atropine 0.5 mg and flunitrazepam 0.5 mg anesthesia was induced with flunitrazepam 0.5 mg, fentanyl 0.1 mg and etomidate 10 mg and maintained with N2O/O2 2:1 and additional increments of 0.1 mg fentanyl as required. Relaxation for intubation and surgery was obtained with non depolarizing muscle relaxants. After the operation the patients were extubated and then flumazenil 0.4 mg, naloxone 0.05 mg, or nalbuphine 20 mg was given i.v. (randomized and double-blind). In 15 patients blood pressure and heart rate were monitored. In all patients postoperative pain was assessed by the time interval between administration of the antagonist and need for the first analgesic medication. On the 1st postoperative day recall of postoperative events and of pictures shown 5, 30, 60, 120, and 240 min after administration of the antagonist was tested. The patients were interviewed a second time for side effects on day 3-6 after the operation. RESULTS. The three antagonists produced no significant effects on arterial pressure and heart rate. There were no differences between the antagonists in the incidence of postoperative nausea and/or vomiting or postoperative pain. After flumazenil, a significant transient increase in vigilance and better recall of postoperative events was noted within 5 and 30 min after administration of the drug. CONCLUSION. On the basis of the objective clinical findings, there is no reason to prefer either benzodiazepine or opiate antagonists after flunitrazepam and fentanyl. However, postoperative amnesia can be reduced by flumazenil if this is desirable.

Adult↗
PubMed1990

[Recovery, amnesia and affective state following propofol in comparison with thiopental].

Numerous reports have described a definite sense of well-being after anesthesia with propofol (Disoprivan). The present study was designed to assess postoperative mood as recorded with a quantitative self-rating method. Postoperative recovery and amnesia were also investigated. Thirty unpremedicated female patients aged 20-60 (ASA grade 1 or 2) who were scheduled for minor gynecological operations were enrolled in the study after informed consent. The patients were randomly allocated to three study groups: group A, induction with propofol 2 mg/kg and maintenance with propofol 0.15 mg/kg per min together with N2O/O2; group B, induction with propofol 2 mg/kg and maintenance with enfluran and N2O/O2; group C, induction with thiopental until loss of the eye lash reflex and maintenance with enfluran and N2O/O2. Postoperative amnesia was assessed by showing five picture cards at 5-min intervals, starting when the patients were able to state the correct date of birth. A test of recovery (p-deletion) was carried out after 30 and again after 60 min. The postoperative mood state was evaluated with the adjective checklist of Janke and Debus 5 h after waking. In good agreement with published reports, propofol patients recovered more rapidly than thiopental patients. A significant but irrelevant amnesia occurred after 5 min in group B. However, in some cases amnesia lasting up to 20 min was observed. The global mood status showed a significantly higher score for positive items and a lower score for negative items after propofol administered by either technique than after thiopental (P = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Propofol infusion for the maintenance of short-term anesthesia].

The administration of propofol by infusion for maintenance of anesthesia has attracted much attention recently. We investigated the necessary infusion rate of propofol to maintain anesthesia for short surgical procedures without loss of the evident advantages of this substance. Forty unpremedicated female patients aged 18-59, scheduled for minor gynecological procedures, were randomly assigned to four groups. Anesthesia was induced with 2.0 mg/kg propofol i.v. and simultaneously an infusion of 0.05, 0.10, 0.15, or 0.20 mg propofol/kg per minute was started. The patients were breathing N2O/O2 with FIO2 33%. Additional propofol was administered as a bolus of 10 to 20 mg when the patients moved. With 0.05 mg propofol/kg per minute all patients required additional bolus injections of propofol; with 0.10 mg 8 patients, with 0.15 mg 5 patients, and with 0.20 mg 1 patient required bolus injection. Therefore, 0.15 mg/kg per minute can be considered as an approximate ED50 value. The total propofol consumption (infusion + bolus) increased from 0.102 +/- 0.028 (+/- SD) with the lowest infusion rate to 0.202 +/- 0.006 mg/kg per minute with the highest infusion rate and recovery time from 5.2 +/- 1.4 to 9.9 +/- 2.6 min. There was a significant correlation between propofol consumption and recovery time. After induction, arterial blood pressure decreased by systolic/diastolic 20/10-15 mmHg. With the low infusion rate, arterial pressure increased to its control value during operation; it remained at the postinduction value with high infusion rates. Side-effects: 10 patients had salivation that in some instances lead to coughing, 9 reported pain at the injection site during induction, and 9 reported dreams of a pleasant nature.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Nalbuphine following fentanyl. Postoperative analgesia].

It has been suggested in various studies that the opiate agonist/antagonist nalbuphine (Nubain) provides for effective reversal of the respiratory depression after fentanyl while maintaining postoperative analgesia. We tested this hypothesis in a relatively large number of patients. The study consisted of two parts: one randomized open, the other randomized double-blind, each with 150 ASA I or II patients aged 18 to 65 years. After premedication with atropine 0.5 mg and flunitrazepam 0.5 mg, anaesthesia was induced with flunitrazepam 0.5 mg, fentanyl 0.1 mg, and etomidate 10 mg and maintained with N2O/O2, 2/1, and additional increments of 0.1 mg fentanyl as required. Relaxation for intubation and surgery was obtained with vecuronium, atracurium, or pancuronium depending on the expected duration of anesthesia. After the operation the patients were extubated and the residual effects of fentanyl antagonized with naloxone 0.05 mg or nalbuphine 10 mg or 20 mg i.v. (randomized open or double-blind). The patient data and fentanyl dosages are given in Table 1. Postoperative pain was assessed by the time interval between administration of the opiate antagonist and the requirement for the first analgesic medication. Figures 1a and b and Table 2 indicate that after nalbuphine 20 mg the first analgesic was required significantly later than after naloxone 0.05 mg (median 115 or 123 min after nalbuphine 20 mg vs 56 or 52 min after naloxone 0.05 mg; P less than 0.02). There was no significant difference between nalbuphine 10 mg and naloxone 0.05 mg. The open and double-blind studies gave virtually identical results. Sixty minutes after administration of 20 mg nalbuphine, vigilance was significantly reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1986

[Disoprivan for the induction and maintenance of short anesthesia].

Disoprivan (Propofol) was used for induction and maintenance of anaesthesia for short surgical procedures in non-premedicated and premedicated (0.5 mg atropine, 3 mg midazolam) patients. A dose of 130-150 mg Disoprivan was adequate for induction, and a dose of 72 and of 62 micrograms/kg body weight/min anaesthesia respectively, for maintenance, together with N2O/O2 2:1. The anaesthesia was characterized by an apnoea of 40-60 s duration, a decrease in arterial blood pressure of 20%, a slowing of heart rate in non-premedicated patients by 12 beats/min and a rapid and pleasant recovery with lack of emetic sequelae. Disoprivan is considered useful for this type of anaesthesia.

Adult↗
PubMed1986

[Nalbuphine after enflurane or fentanyl--effect on circulation and respiration].

The agonistic and antagonistic properties of nalbuphine were examined in 80 surgical patients after anaesthesia consisting essentially of flunitrazepam/enflurane or flunitrazepam/fentanyl. After the operation the intubated and still unconscious patients were breathing either N2O/O2/enflurane 0.4 Vol.% or N2O/O2 (FIO2 0.33). The mean fentanyl requirement during operation was 0.55 microgram/kg body weight/10 min anaesthesia. The respiratory minute volumes (RMV) were similar in all groups and ranged between 77-89% of the calculated normal value. The respiratory rate was 18-23/min in the enflurane groups and 11-12/min in the fentanyl groups. After reaching a circulatory and respiratory steady state, nalbuphine was administered i.v. in the doses of 2.5, 5, 10 or 20 mg. In the enflurane groups nalbuphine produced a pure depressant effect on respiratory parameters. The RMV decreased by 27 +/- 3%, the calculated alveolar ventilation by 20-24% and the breathing rate by 6 breath/min. A new steady state was reached within 10 min. The well-known ceiling effect was observed. In contrast to the observations in awake patients the maximum depressant effect was already reached after a dose of only 5 mg nalbuphine. Arterial blood pressure decreased by 4-5 mmHg and heart rate by 5 beats/min. After fentanyl, however, nalbuphine in all doses exhibited a stimulating effect on respiration and circulation. A steady state was reached after 10 min as well. A maximum effect on alveolar ventilation (+ 39 +/- 8%) was obtained after 5 mg nalbuphine and did not increase further with increasing doses. The effects on RMV and on respiratory rate were dose dependent. Arterial blood pressure increased slightly as did heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

[Comparative clinical studies of vecuronium, atracurium and pancuronium].

The new relaxants vecuronium (Norcuron) and atracurium (Tracrium) have been compared with pancuronium (Pavulon) with respect to onset and duration of action and intubating conditions under clinical situations. A variant of the balanced anaesthesia technique with flunitrazepam, fentanyl and N2O/O2 was used. The following doses were considered equipotent (mg/kg body weight): vecuronium 0.07/0.10; atracurium 0.35/0.50; pancuronium 0.08/0.115. The degree of neuromuscular block was assessed in a semiquantitative manner, using the train of four. No difference between the three relaxants in onset of action was found. After the high doses, however, full paralysis developed 60 s earlier. The same is true of intubating conditions. Good or very good intubating conditions were obtained in the majority of cases 3 minutes after injection of the drug. Following the higher dose, good intubating conditions are achieved approximatively 1/2-1 min sooner. Both new relaxants allow for relatively rapid intubation without the inconvenience of a long duration of action. After a low initial dose the following time for recovery to 25% was noted (means +/- S.D., min): vecuronium 20.3 +/- 7.0; atracurium 28.0 +/- 3.1; pancuronium 53.3 +/- 14.8. The early recovery phase (from 5% to 25% recovery) was 6.1 +/- 2.4 after vecuronium, 8.3 +/- 1.7 after atracurium, 17.2 +/- 10.8 after pancuronium. There is a good correlation between our semiquantitative results, using the train of four, and quantitative recordings of muscle contractions reported in the literature. Both drugs show no cumulative effect after five repeated administrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

[Comparative clinical studies on vecuronium, atracurium and pancuronium in older patients].

The relaxants vecuronium (Norcuron), atracurium (Tracrium), and pancuronium (Pavulon) have been investigated with respect to onset and duration of action in old patients compared with young patients. A variant of a balanced anaesthesia technique with flunitrazepam, fentanyl and N2O/O2 was used. The following equipotent doses were investigated (mg/kg body weight): vecuronium 0.07/0.10; atracurium 0.35/0.50; pancuronium 0.08/0.115. The neuromuscular function was assessed in a semiquantitative manner with the Train-of-Four (TOF). We found a trend to a delayed onset of action in old patients. This effect, however, reached a significant level with pancuronium only. The degree of relaxation after comparable doses was less after atracurium in old patients. This difference between young and old patients could not be observed after vecuronium and was hardly detectable after pancuronium. The duration of action to a 25% recovery and the early recovery phase from the appearance of the first to the fourth twitch in the TOF showed no difference between young and old patients. It is concluded that there are no considerable differences with respect to the duration of action between young and old patients. However, to obtain a similar degree of relaxation, it is recommended to use a somewhat higher dose level with atracurium.

Adolescent↗
PubMed1983

[Ranitidine (Zantic) for aspiration prevention].

The new H2-receptor antagonists have been shown to be effective against the risk of gastric acid aspiration. The recommended dosage schedules, however, are not satisfactory in a clinical routine practice. Therefore the effect of the long acting agent ranitidine on pH and volume of gastric secretion after a single administration at 22.00 h on the previous evening has been investigated. Ranitidine 300 mg increases pH in all cases to values higher than 3.5 at 08.00 on the next morning. Ranitidine 150 mg and cimetidine 400 mg are not satisfactory, as expected. If an anaesthetic is scheduled to start later than 09.00, an additional dose of ranitidine should be administrated at 07.00. Ranitidine 300 mg provides an efficient prophylaxis against acid aspiration in one single dose and without additional medications at a time inconvenient for patient and nursing staff.

Anesthesia, General↗
PubMed1979

[Acupuncture-analgesia/anesthesia: placebo for physician and patient?].

Various non-pharmacological analgesic procedures are attracting interest as a means of treating chronic pain (acupuncture, transcutaneous nerve stimulation, dorsal column stimulation, subcortical stimulation). The gate-control theory and activation of endorphin mechanisms are discussed as explanatory hypotheses for the analgesic effect. The proof of analgesic action in addition to the ever-present placebo effect is difficult. However, in unconscious, superficially anesthetized patients undergoing hysterectomy an analgesic effect of electrostimulation has been demonstrated which resulted in a significant reduction in the need for additional anesthetics. Speculation regarding the future of this method is premature in view of many unanswered questions.

Acupuncture Therapy↗