Search PubMed⌕ Search

Biomedical subjects

H Schaer

Publications and source records attributed to H Schaer.

At least 37 records · Page 2Linked to original sources
PubMed1978

[Respiratory depression after fentanyl and antagonism by naloxone (author's transl)].

The postoperative respiratory depressant effect of fentanyl in combination with flunitrazepam (Rohypnol) was assessed in awake and in unconscious patients. In awake patients respiratory function was measured with blood-gas analyses. For measurements in unconscious patients the administration of nitrous oxide/oxygen was continued postoperatively and the respiratory depression was judged from the increase in respiratory minute volume after the i.v. administration of 0.05 mg naloxone (Narcan). In the group of awake patients blood-gasvalues were within the normal range after anaesthesia with flunitrazepam (1 mg) and fentanyl (0.80 mcg/kg body weight/10 min anaesthesia; last fentanyl given 40 min before the end of the operation), and the administration of naloxone was without any effect. If, however, naloxone was given while the patients were kept under light nitrous oxide/oxygen anaesthesia, the effect was different. The respiratory minute volume was considerably less than its predicted value in all groups of patients having received fentanyl, and naloxone caused a marked increase in respiratory minute volume and in respiratory rate. In a group of patients which have received no opiate but enflurane, naloxone showed no effect. After premedication with pethidine as compared with flunitrazepam the effect of naloxone on ventilation was more pronounced. This marked difference in the postoperative effect of fentanyl on ventilation depending on the state of consciousness has to be attributed to an interaction between a residual respiratory depressant effect of fentanyl and the effect of unconsciousness. Since after the combined use of flunitrazepam and fentanyl deep postoperative sleep occurs quite frequent, a residual effect of fentanyl should always be antagonized with naloxone to protect the patients from a possible hazardous effect of this interaction.

Adolescent↗
PubMed1978

[Effects of tilidin and naloxone on pulmonary function (author's transl)].

The respiratory depressant effect of tilidine (valoron) was investigated in anaesthetized patients. One hundred mg of tilidine had a slight respiratory depressant effect which was without importance in awake subjects. The respiratory depression caused by tilidine could be antagonized by naloxone while the analgesic effect was maintained. This suggests a dissociation of the mechanisms responsible for the respiratory and the analgesic actions.

Adolescent↗
PubMed1977

[Anaesthesia with flunitrazepam (rohypnol) and fentanyl for geriatric patients (author's transl)].

Favorable clinic experiences with an anaesthetic involving rohypnol (flunitrazepam) and fentanyl led to an investigation of the haemodynamic effect of this procedure in a group of 9 geriatric patients, aged from 86 to 95 years. Anaesthesia was induced with 0.5 mg rohypnol and 0.1 to 0.2 mg fentanyl depending on the narcotic effect of rohypnol, intubation was performed under relaxation with suxamethonium and long term relaxation was achieved with pancuronium. The patients were normoventilated with nitrous oxide/oxygen. The individual values of the changes in cardiac output and total peripheral resistance showed a great variation. There was a significant correlation between the relative changes in mean arterial pressure and total peripheral resistance (r = 0.69, p less than 0.05) but no correlation between mean arterial pressure and cardiac output (r = 0.09). This indicates that the pronounced drop in arterial pressure which occurred in 4 patients can be explained by a decrease in total peripheral resistance. Careful dosage of the drugs, in particular of fentanyl, and knowledge of adequate measures to treat a decrease in blood pressure if it occurs, appears to be a prerequisite for the use of this type of anaesthesia in poor risk patients.

Age Factors↗
PubMed1977

[Pulmonary oedema ex vacuo (author's transl)].

Spontaneous respiration in the presence of upper airway obstruction causes considerable negative intra alveolar pressure which may lead to pulmonary oedema "ex vacuo". Four cases are presented of spontaneously breathing patients who sustained upper airway obstruction lastin from one to several hours, leading to manifest pulmonary oedema. The pathogenesis of pulmonary oedema ex vacuo is discussed on the basis of alteration of physiological parameters such as capillary, alveolar and pleural pressures, as well as the properties of lung liquid exchange. In contrast, pulmonary oedema occurring after re-expansion of a collapsed lung is reported in one patient. No negative intraalveolar pressure could be incriminated in this case since the patient was ventilated using intermittent positive pressure from the beginning of lung expansion. We tend to attribute the evolution of this second kind of pulmonary oedema to capillary damage, resulting from hypoperfusion of the atelectatic areas, altered alveolar surface lining layer, infection and other cases. The therapeutic measures used in pulmonary oedema "exvacuo" are briefly mentioned.

Adult↗
PubMed1976

Effects on ionized calcium of a correction of acidosis with alkalinizing agents. A rational basis for the administration of calcium in cardiac resuscitation.

The effects on the ionized calcium concentration of a correction of various forms of acidosis with sodium bicarbonate or (tris-hydroxymethyl)aminomethane (THAM) were investigated in vitro in human plasma. Calculation of least square regression equations of ionized calcium (m mol) on pH yielded the following regression coefficients: hydrochloric acidosis: -0.65 +/- 0.06; lactic acidosis: -0.27 +/- 0.05; hydrochloric acidosis corrected with sodium bicarbonate: -0.65 +/- 0.02; lactic acidosis corrected with sodium bicarbonate: -0.51 +/- 0.03. The results indicate that after correction of lactic acidosis the ionized calcium concentration will be below the control values while pH is restored to the normal range. This effect is even more pronounced when THAM is used. The findings point to the need for calcium administration in cardiac resuscitation.

Acidosis↗
PubMed1976

[Effect of volume substitution with dextran on the haemodynamics under enflurane anaesthesia in geriatric patients (author's transl)].

The haemodynamic effect of enflurane has been examined in two groups of geriatric patients, one with and the other without preanaesthetic administration of 15 mg/kg of 1,8% dextran in lactated Ringer's solution. All the patients have been immobilized for 2 to 3 days before they were operated for an orthopaedic procedure. The administration of the colloidal solution led only to minor cardiovascular alterations: a rise of central venous pressure by 6 +/- 1 (+/- S.E.M.) cm H2O, an increase of mean arterial pressure by 6 +/- 2%, an increase of cardiac output by 10 +/- 4%. Heart rate decreased by 5 +/- 4% and total peripheral resistance by 12 +/- 5%. The cardiovascular depressant effect of enflurance was markedly attenuated by the preanaesthetic volume administration. Mean arterial pressure decreased during anaesthesia by only 16 +/- 3%, as compared with a decrease of 25 +/- 7% in the control group, cardiac output remained virtually unchanged (-3 +/- 9% vs. -37 +/- 5% in the controls) and total peripheral resistance decreased not significantly by 10 +/- 12%, while it rose in the controls by 20 +/- 8%. These findings support the hypothesis that the particular sensitivity of geriatric patients towards the depressant effects of anaesthetics is at least partially due to a compensated hypovolaemia which occurs as a physiological adaptation to immbolization. Enflurane appears as a suitable anaesthetic for geriatric patients, if proper measures for preanaesthetic volume substitution are taken.

Age Factors↗
PubMed1975

[Effect of ethrane on the circulatory parameters of geriatric patients (author's transl)].

The cardiovascular effects of enflurane in geriatric patients have been compared with the effects of this anaesthetic agent in a group of young patients. The degree of cardiovascular depression in geriatric patients was much greater than in the young patients despite the smaller inspired concentration of enflurane necessary to produce a similar depth of anaesthesia. In comparison with halothane and neuroleptanaesthesia, enflurane produced the greatest decrease in cardiac output. The mean arterial pressure, however, was quite well maintained due to a simultaneous increase in total peripheral resistance.

Adult↗