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Biomedical subjects

J Schou

Publications and source records attributed to J Schou.

At least 19 recordsLinked to original sources
PubMed1992

[The effect of etomidate on the upper airway reflexes].

Clinical observations during anaesthesia and intubation of emergency patients are presented showing a differentiated impact of etomidate (Hypnomidate) on upper airway reflexes: a blockade of pharyngeal reflexes with sustained but possibly delayed laryngeal reflexes and a certain protection against laryngospasm and vomiting. In addition etomidate enables, preferably in combination, difficult intubation with sustained spontaneous breathing due to its low respiratory depressant effect. These features were confirmed in a small foreshortened clinical study using thiopentone (Trapanal) or etomidate without muscle relaxants, whereby the difference in high risk patients became obvious. The impact of anaesthetics on airway reflexes is generally concealed by muscular relaxants, and observations on this matter are difficult to make subject to quantifiable parameters and controlled studies; accordingly such observations are scarcely found in newer anaesthetic literature. In the development of new techniques for intubation and anaesthesia without muscle relaxation, these methodical problems deserve attention.

Etomidate↗
PubMed1992

[Pneumothorax and cardiac arrest as complications of postoperative nasopharyngeal administration of oxygen].

An unusual but life-threatening complication to nasopharyngeal oxygen administration is described. Following an unsuccessful attempt to advance nasogastric tube during anesthesia for cholecystectomy, the same nostril was used for an oxygen catheter at the end of operation. Within a few minutes after the oxygen supply had been opened following extubation, the patient developed submucous pharyngeal and mediastinal emphysema with subsequent bilateral pneumothorax and cardiac arrest. The patient was reintubated, received close-chest cardiac compressions for a brief period, and the pneumothoraces were drained. She recovered completely within a few hours and was extubated uneventfully the following day. With the increasing--and justified--use of oxygen postoperatively in and during transport to the recovery room, this complication is likely to occur more often. In this case, the anesthetist's previous experience of this complication and consequent rapid therapeutic intervention was probably responsible for the favorable outcome.

Aged↗
PubMed1991

Evoked potentials in urology: a method to make an exact diagnosis?

Due to the complex innervation of the lower urinary tract, many neurological diseases will lead to disturbances in the function of the lower urinary tract. The usual urodynamic procedures leave a group of patients where definitive diagnosis is impossible. Fifty-three patients were evaluated with evoked potentials of the bulbocavernosus reflex at the Urological Laboratory, Herlev Hospital. In 5 cases (2 with operative sequelae after prolapsed intervertebral discs, 1 with tethered cord syndrome and 2 with early multiple sclerosis) the examination gave a definitive diagnosis. The cases are reported.

Adult↗
PubMed1990

The elasticity and the tensile strength of tunica albuginea of the corpora cavernosa.

The aim of this study was to determine the tensile strength and the elasticity of the tunica albuginea (TA), and describe morphological structures in the tissue before and after mechanical deformities. Twenty cadavers of men aged between 33 and 83 were examined. Cavernosometry was performed in all specimens. Afterwards in five cadavers the flow rate was increased until a herniation of the TA appeared. A strength about 1500 mm. Hg was found. Similar results were found in four who had an inflatable prosthesis (AMS 700) inserted, and the intraprosthetic pressure increased until a deformity was noted. Slices of TA (thickness 1.3 to 3.3 mm.) from 11 specimens were tested in a tensiometer. The elasticity coefficient was found to be around 10(8) N/m2, and the tensile strength to be 600 to 750 mm. Hg (10(4) to 10(5) N/m2). The difference between the tensile strength achieved in the tensiometer and during saline infusion is possibly caused by the intracavernous framework. Microscopy showed that TA is mainly composed of collagen fibres which are situated in an undulating arrangement, with a few elastic fibres arranged longitudinally which connect the undulating bundles of collagen fibres. When the tissue is overstretched, the elastic fibres are destroyed and the undulating arrangement disappears.

Adult↗
PubMed1990

[The double mask].

While the consequences of occupational exposure to anesthetic gases and volatile agents on morbidity in operating room staff are controversial (survey in Swiss investigations show a distinct correlation with subjective complaints, e.g. tiredness and headache on the day of exposure (Table 1). In Sweden, rigorous control of occupational exposure to anesthetic gases has prompted development of various scavenging systems, among which the double mask (Fig. 1) is the latest and most advanced. During mask anesthesia, escaping anesthetic gases are evacuated at the point of leakage via a thin slot between a flexible silicone inner mask and a rigid plastic outer mask. A small plate in the mask produces turbulence in the otherwise laminar flow of anesthetic gases, thus reducing the speed of gas leakage. A silicone chamber is mounted on the mask and connected to a fan, requiring a flow of 35 m3/h for optimal function. This chamber does, however, also associate the system with two practical problems: the system with its evacuation tube is heavier to hold than conventional masks, and it is associated with increased dead-space that is only partly minimized by a modification of the Y-connector. While the handling is largely a matter of routine and the weight of the system is minimized when the evacuation tube is arranged to draw slightly upward, the increased dead space may reduce the practicality of the double mask in infants.

Gas Scavengers↗
PubMed1989

[Injury patterns on the first icy day of winter--a survey in Copenhagen County].

The injuries on the first icy day of the winter 1986-1987 in Copenhagen County were compared to the injuries on the preceding day. There were 368 and 276 injuries (both days 95 non-surgical) respectively. The significant increment of fractures and emergency hospitalization was mostly due to fractures of the wrist, humerus and femur. Only a few sprains of the ankle were registered. The majority of patients were middle aged and elderly women. The economical and personal consequences are considerable, but impossible to evaluate, as reliable statistics are needed. Intensive snow clearing and recurrent propaganda are recommended.

Accidental Falls↗
PubMed1987

[Therapy of paradoxical reactions to midazolam in regional anesthesia].

Many patients fear being awake in the operating room, and the acceptance of regional anesthesia is often made dependent on the promise of adequate sedation. With the introduction of the short-acting benzodiazepine (bzdp) midazolam, it seemed possible to achieve induction and maintainance of sleep throughout an operative procedure. This substance may, however, occasionally result in a "paradoxical reaction" (PR) characterized by agitated excitement, mental confusion, and uncooperativeness. We have treated this condition successfully with physostigmine, as documented here in two case reports where a possible interaction between promethazine and midazolam may have been responsible for the PR. The symptoms resemble some of those seen in the central anticholinergic syndrome, as further implied by the therapeutic effect of physostigmine, but an etiological difference may exist. A direct anticholinergic effect of bzdp's is described only following excessive doses. An indirect effect may result from the impact on GABA-receptors, which have been identified as structurally related to the bzdp receptors. Physostigmine itself is not bound at the bzdp receptor, but has been shown to block the binding of bzdp's to their receptors and to reverse sedation from midazolam, perhaps through an indirect stimulatory effect. Previous case reports have indicated the effect of physostigmine in reversing PR following various bzdp's. Without treatment, a PR during regional anesthesia frequently makes general anesthesia necessary in order to immobilize the patient sufficiently to make surgery possible.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Dextropropoxyphene kinetics after single and repeated oral doses in man.

The kinetics of dextropropoxyphene (DP) and its main metabolite norpropoxyphene (NP) were studied in 6 healthy male subjects after a single oral dose of 195 mg DP HCl, and during and after 12 daily single oral doses of 195 mg DP HCl. The kinetics varied up to five-fold between individuals after the single dose, the apparent mean elimination half-life (t1/2) was 16 h for DP and 29 h for NP. The mean apparent overall plasma clearance (CL) for DP was 2.61/min. There was no systematic difference in DP clearance between the single and multiple doses, but the accuracy of individual predictions from single to multiple doses was poor, probably because of imprecise determinations of the AUC and t1/2 in the single dose experiments. The individual correlation between single and multiple dose kinetics was good for NP, although the predicted plasma levels during steady state were significantly higher than the observed levels (mean AUCss/AUCsd: 0.81). There was no sign of saturation kinetics on repeated administration. In fact, autoinduction, resulting in significantly lower plasma concentrations after treatment for 1 week was found for NP and was indicated for DP. On discontinuing DP after 12 days of treatment, the apparent mean t1/2 of DP was 23 h and of NP 25 h.

Administration, Oral↗
PubMed1979

d-Propoxyphene kinetics after single oral and intravenous doses in man.

d-Propoxyphene kinetics was studied in 8 healthy male subjects after single oral doses of d-propoxyphene at 65, 130, and 190 mg and after slow intravenous infusion of 65 mg. Total urinary excretion (7 days) indicated complete oral absorption but systemic availability was reduced corresponding to fist-pass elimination of 30% to 70%. There was linearity between oral dose and the corresponding area under the plasma concentration/time curve of d-propoxyphene and the metabolite norpropoxyphene. The kinetic measurements showed 2- to 3-fold interindividual variations: oral clearance, 1.3 to 3.6 1/min; systemic clearance, 0.6 to 1.2 1/min; apparent volume of distribution, 700 to 1,800 1; d-propoxyphene half-life (t1/2), 8 to 24 hr; and norpropoxyphene t1/2, 18 to 29 hr. There were pronounced intraindividual dose-dependent variations in oral clearance in some subjects. The intravenous concentration curves indicated a 3-compartment distribution model.

Administration, Oral↗
PubMed1979

Entrance into brain of dextropropoxyphene and the toxic metabolite norpropoxyphene.

Several studies show that dextropropoxyphene after oral administration is intensively biotransformed to norpropoxyphene by first pass metabolism in the liver. While dextropropoxyphene is analgesic, cardiotoxic and shows CNS toxicity with convulsions and respiratory depression, norpropoxyphene is cardiotoxic to the same degree as dextropropoxyphene, but is without analgesic or CNS-toxic effects (Lund-Jacobsen, 1978). This principal difference between the effects of dextropropoxyphene and norpropoxyphene might be due to differences in penetration into the brain. We investigated the penetration of the two compounds in 14C-labelled moities into the brain of rats by the technique originally described by Oldendorf (1970). By this method the extraction of dextropropoxyphene was found extremely high, while it was much lower for the metabolite. The extraction percentage for dextropropoxyphene after 5 and 10 S was 350 +/- 34.1 and 164 +/- 15.2, respectively, while the values for norpropoxyphene was 62 +/- 6.2 and 44 +/- 4.1 (mean +/- S.E.M.), respectively. This difference may at least partly explain the missing CNS-symptoms with the metabolite.

Animals↗
PubMed1978

Pharmacokinetics of dextropropoxyphene in acute poisoning.

Dextropropoxyphene (DP) is a commonly used medicament for suicide attempts in Denmark. Death may occur from respiratory depression or cardiac arrest. Mechanical hyperventilation which induces hypocapnia seems to reduce the occurrence of cardiac complications. In an attempt to relate the clinical events to the plasma concentrations of DP and the major metabolite norpropoxyphene (NP) we studied patients with acute poisoning treated either for 48 h with induced hypocapnia by hyperventilation or under a conservative regime. Hypocapnia was found to lead to a significant increase in the plasma half-life of DP. Under conservative treatment the plasma half-life was 17.9 +/- 6.7 (S.D.) h (n = 6), while under induced hypocapnia the mean of values from 5 patients was 30.5 +/- 6.9 (S.D.) h. Maximum serum levels of DP and NP were, however, significantly higher in the intensively treated patients (n = 7) than in those treated conservatively (n = 9), though less marked for NP compared to DP (DP: 4.9 +/- 2.1/2.4 +/- 1.0 mumol/l, NP: 6.3 +/- 2.4/4.1 +/- 1.7 mumol/l). A concentration dependent renal clearance of NP was not demonstrable. Possible explanations are the following: 1) A change in disposition pattern blood/tissue of DP during hypocapnia. 2) A reduced metabolism DP to NP during hypocapnia. 3) A reduction in other routes of elimination.

Biotransformation↗
PubMed1977

Penetration of delta-9-tetrahydrocannabinol and 11-OH-delta-9-tetrahydrocannabinol through the blood-brain barrier.

The relative brain uptake (extraction into brain) of delta-9-tetrahydrocannabinol (delta-9-THC) and the primary metabolite 11-OH-delta-9-tetrahydrocannabinol (11-OH-delta-9-THC) was measured after close intracarotid injection in rats of radiolabelled moities using labelled antipyrine as reference. The extraction percentage was of the same magnitude when injections were given in saline, 66 +/- 11% and 70 +/- 9% respectively after 5 sec., 59 +/- 4 and 67 +/- 8 respectively after 15 sec. While the extraction of 11-OH-delta-9-THC was the same when injected into plasma, the extraction of delta-9-THC was only about half of the extraction from saline, and also half the extraction of the metabolite from plasma. The higher uptake quantity of the metabolite into the brain may account for the relatively greater effect on the central nervous system of the metabolite than of the parent compound at equal concentrations in plasma. Moreover our experiments demonstrate that 11-OH-delta-THC formed in the liver after cannabis (delta-9-THC) administration may exert significant brain effects.

Animals↗