J. Strøm

Acute carbon monoxide poisoning.

The course and outcome in terms of cerebral morbidity and hospital mortality in 79 severely carbon monoxide poisoned patients admitted to the intensive care unit during a period of 15 years is presented. Treatment consisted of administration of pure oxygen. Ninety–four per cent of the patients were artificially hyperventilated, and the majority of the patients were also treated with moderate hypothermia, steroid hormones and diuretics. Hospital mortality was 30%, and 14% of the patients were discharged after long–term hospital treatment with signs of brain damage. Due to the unpredictable cerebral course after the acute incident long–term follow–up is recommended.

Acute self-poisoning with tricyclic antidepressants in 295 consecutive patients treated in an ICU

Clinical findings on admission to hospital and outcome in 295 consecutive patients with severe tricyclic antidepressant self‐poisoning treated in an ICU are presented. Cerebral depression was observed in 92%, convulsions in 23% and respiratory failure was present in 72%. Cardiovascular function was impaired in 44% and an abnormal ECG was found in 57%. Cardiac arrest was treated in 14 patients (6%) of whom seven were resuscitated. The mortality rate was 2%. All patients were artificially ventilated. A beneficial effect of respiratory alkalosis on cardiac arrhythmias is supported.

Acute salicylate self‐poisoning in 177 consecutive patients treated in ICU

The course of 177 consecutive patients with severe salicylate self‐poisoning treated in an intensive care unit (ICU) during a period of 15 years is presented. On admission, cerebral depression was observed in 61%, respiratory failure was present in 47%, acidosis in 36% and cardiovascular function was impaired in 14%. A mortality rate of 15%, was observed, which was proportionally higher in patients more than 40 years old and in patients with delayed diagnosis. Twenty‐seven patients died and an autopsy was performed on 26 patients. The main autopsy diagnosis was ulcers of the gastrointestinal tract in 46%, pulmonary oedema in 46%, cerebral oedema in 31% and cerebral haemorrhage in 23%.

Acute propoxyphene self-poisoning in 222 consecutive patients

The course of severe propoxyphene self‐poisoning in 222 consecutive patients is presented. On admission, 73% of the patients had neurological symptoms, 10% had convulsions, 45% were in respiratory failure, and impaired circulation was present in 48%. A mortality rate of 8% was observed. Twelve patients arrived in asystole of whom six were resuscitated without sequelae. The overdose was accidental in 13 patients, one of whom died. Early medical intensive care was found mandatory for a good prognosis. Before discharge from the ICU we recommend an observation‐period free of cardiovascular symptoms for 24 h.

Catecholamine response to laryngoscopy and intubation. The influence of three different drug combinations commonly used for induction of anaesthesia.

The haemodynamic response and changes in plasma catecholamine concentrations associated with laryngoscopy and tracheal intubation were compared during anaesthesia employing three strictly standardised techniques with commonly used drug combinations. Thirty‐six patients were investigated consecutively resulting in 12 patients in each of three study groups. Anaesthesia was induced with thiopentone 5 mg.kg−1 (group 1), fentanyl 6 ng.kg−1 with thiopentone 5 mg.kg−1 (group 2). or midazolam 0.2 mg.kg−1 with fentanyl 6 ug.kg−1 (group 3). Undesirable changes in haemodynamic effects and an elevation of plasma catecholamine concentrations during laryngoscopy and intubation occurred in group 1. Heart rate and mean arterial pressure increased significantly (34% and 23% respectively). Noradrenaline concentration increased by a maximum of 147%. The addition of fentanyl (groups 2 and 3) attenuated the adverse haemodynamic response and elevation of plasma catecholamine concentrations; heart rate and mean arterial pressure did not differ from pre‐intubation values and plasma catecholamine concentrations decreased steadily. Substitution of thiopentone by midazolam in combination with fentanyl abolished the adverse haemodynamic response and modified the increase in plasma catecholamine concentrations. ‘High‐dose’ opioid anaesthesia is not necessary to produce optimal conditions during laryngoscopy and intubation.

Self‐poisoning treated in an ICU: drug pattern, acute mortality and short‐term survival

A total of 1558 admissions to an ICU over 5 years because of severe self‐poisoning with drugs provides the basis for this study. Three drugs accounted for 60% of the admissions: overdose with barbiturates in 28%, with tricyclic antidepressants in 19% and with propoxyphene in 14%. The annual incidence of poisonings with barbiturates and tricyclic antidepressants was the same during the period, whereas the incidence of propoxyphene intoxication increased by 80%. Intensive supportive care was the main principle of treatment. All patients were artificially ventilated. The mortality rate was 6.1%, salicylate, propoxyphene and strong analgesics having the highest mortalities (11%, 9% and 9%, respectively). A mortality rate of 3% was found following overdose with tricyclic antidepressants. By 36 months after the overdose, 235 patients (18%) had died. The expected number of deaths was 39 (3%). The suicide rate in the follow‐up period was 10%, in the majority (75%) of whom death was caused by a new episode of self‐poisoning.

Cardiovascular effects of pentobarbital in pigs, and the lack of response to naloxone in pentobarbital induced circulatory failure

The hemodynamic effects of pentobarbital were tested in an experimental model used for cardiovascular research. Anesthesia was induced with an i.v. bolus and maintained with a continuous infusion of pentobarbital. The cardiovascular performance was then evaluated at various pentobarbital plasma concentrations ranging from 25 to 100 mg·l‐1. Optimal experimental conditions were found at plasma pentobarbital concentrations within the range 40–60 mg·l‐1, as the animals were well anesthetized with intact hemodynamics or ECG. The method of continuous pentobarbital administration seems advantageous for experimental research. Circulatory impairment following pentobarbital overdose was not affected by naloxone.

Severe acute propoxyphene overdose: plasma concentrations of propoxyphene and norpropoxyphene and the effect of dopamine on circulatory failure

Twelve patients with cardiovascular failure because of propoxyphene self‐poisoning were treated with dopamine. The patients responded favourably to dopamine infusion (2–17 μg/kg/min) with a dose‐dependent rise in systolic arterial blood pressure and a fall in central venous pressure and copious urinary output. Side effects during infusion were few, and in periods where dopamine infusion exceeded 10 μg/kg/min no tachyarrhythmias were seen. Eleven of the patients were treated on a respirator. Two patients were discharged from the ICU with signs of hypoxic brain damage, one of whom recovered completely after 2 weeks. Serum propoxyphene and norpropoxyphene were measured in nine patients. All but one patient had either propoxyphene or norpropoxyphene concentrations above 3 μmol/l.

Cardiovascular effects of pregnanolone emulsion: an experimental study in artificially ventilated dogs

The acute cardiovascular effects of pregnanolone emulsion, a new steroid preparation for intravenous anaesthesia, were investigated in artificially ventilated dogs. The anaesthetic was administered as repeated intravenous bolus injections, doubling the dosage with each injection. The plasma concentration of pregnanolone, and the haemodynamic, respiratory and metabolic variables were determined after each injection. Cardiac output and heart rate increased from the first bolus dose of the anaesthetic (0.5 mg/kg), which produced anaesthesia lasting 10 to 15 min. Both continued to increase after administration of 1.0, 2.0 and 4 mg/kg, whereas reductions of systemic arterial pressure and estimated myocardial contractility were observed only at the two highest dosages. A decrease in vascular resistance was calculated in the systemic circulation, whereas vascular resistance increased in the pulmonary circulation. A state of circulatory shock followed administration 8, 16 and 32 mg/kg of the anaesthetic.

The Effects of Naloxone on Central Hemodynamics and Myocardial Metabolism in Experimental Propoxyphene‐Induced Circulatory Shock

The courses of the hemodynamic and cardiometabolic effects of naloxone were evaluated in propoxyphene‐induced shock in eight pentobarbital‐anesthetized pigs. Circulatory shock was induced by an infusion of propoxyphene chloride 15 mg·min‐1 i.v. At shock, i.e. MAP<60 mmHg and/or CI<2.0 l·min‐1·m‐2, naloxone was administered at 0.75, 1.5 and 3.0 mg·kg‐1 with an interval between increments of 8 min. The propoxyphene infusion of 15 mg·min‐1 was continued throughout the study. Following the injection of naloxone 0.75 mg·kg‐1, increases were observed (% of baseline value) in MAP (41%), i.e. deficit to baseline 59%, HR (66%), CI (67%) and SVI (108%), whereas MPAP and MPAOP were unchanged. dP/dt increased (34%). In the coronary circulation naloxone initiated the following changes: CSF increased (69%) as did MVo2 (48%) with unchanged Mo2‐extraction, but CVR decreased further (36%). The maximum effects of naloxone were registered 2–3 min after 0.75 mg·kg‐1. Following 1.5 and 3.0 mg·kg‐1, no changes in hemodynamics were observed other than those caused by progressing propoxyphene intoxication.