[Prevention of aspiration in obstetric patients in Denmark]. / Aspirationsprofylakse hos obstetriske patienter i Danmark.

Women about to undergo Caesarean section are especially prone to suffer from aspiration of acid gastric contents into the lungs during anaesthesia. Physiological changes in the pregnant patient make gastric emptying time unpredictable. It therefore seems prudent to establish procedures in order to minimize the risk of aspiration of gastric contents. This survey reveals that 25% of the obstetric-anaesthesiological departments in Denmark employ pharmacological prophylaxis for aspiration of acid gastric contents. This finding is in contrast to a similar survey in the United Kingdom, where 99 to 100% of the Caesarean sections are carried out under pharmacological prophylaxis for aspiration of acid gastric contents.

Alfentanil infusion in total intravenous anaesthesia (TIVA). Population pharmacokinetics fails to predict plasma concentration of alfentanil.

In order to evaluate the ability to predict plasma concentrations from population-corrected pharmacokinetics, a prospective study comprising 14 women admitted for elective hysterectomy was done. Alfentanil was given in combination with propofol in a total intravenous anaesthesia technique. The predicted median alfentanil concentration (289(256-363) ng ml-1) was significantly lower than the measured median plasma concentration of 368(168-666) ng ml-1). In conclusion, population-based pharmacokinetics were found not to be accurate as they underestimate plasma concentrations of alfentanil.

Total intravenous anaesthesia with propofol or etomidate.

In combination with fentanyl, propofol was compared with etomidate for total intravenous anaesthesia in 21 women (ASA Grades I-II) admitted for elective hysterectomy. They received either propofol (bolus 1.5 mg kg-1, infusion 9 mg kg-1 h-1 for 10 min thereafter 6 mg kg-1 h-1) or etomidate (bolus 0.10 mg kg-1, infusion 3 mg kg-1 h-1 reduced to 0.6 mg kg-1 h-1). Fentanyl 10 micrograms kg-1 was given for induction followed by an infusion of 30 micrograms kg-1 h-1 for 10 min reduced to 6 micrograms kg-1 h-1 for the first hour and successively reduced over time. Induction was smooth and maintenance easy to manage in both groups. There was no difference in time from end of infusion until extubation, but the time until the patients could report their date of birth was significantly shorter in the propofol group. Nausea and vomiting were more pronounced in the etomidate group, and mental side-effects were only seen after etomidate. After 3 months, more patients in the etomidate group complained of reduced power of concentration. We conclude that total intravenous anaesthesia with either propofol or etomidate is equally easy to manage, but in the recovery situation propofol was advantageous in time and quality.

Awakening and recovery of simple cognitive and psychomotor functions 2 h after anaesthesia for day-case surgery--total intravenous anaesthesia with propofol-alfentanil versus thiopentone-alfentanil.

Fifty-seven patients undergoing minor out-patient gynaecological procedures were allocated to one of two total intravenous anaesthesia regimes: propofol and alfentanil or thiopentone and alfentanil. Diazepam was given orally as premedication. To assess objectively the quality of recovery, the patients underwent a number of tests pre-operatively and two hours post-operatively. The time to opening of eyes and orientation was equal in both groups, as was the recovery of the tested cognitive and psychomotor functions after 2 h, when the score in both groups had returned to baseline. We conclude that the use of propofol instead of thiopentone for shorter surgical procedures gives no advantage as regards length of stay in hospital.

[Lumbar regional analgesia in patients during antithrombotic treatment. Procedures used at the Danish anesthesiologic departments illustrated by a questionnaire study]. / Lumbal regional analgesi til patienter i antitrombotisk behandling. Procedurer på danske anaestesiafdelinger belyst ved en enqueteundersøgelse.

The attitudes of Danish anaesthetists to employment of lumbar epidural analgesia (EA) or spinal analgesia (SA) in patients receiving perioperative antithrombotic therapy was assessed by a questionnaire investigation. EA and SA were absolute or relative contraindications in patients receiving low-dose heparin therapy in 38% and 24% of the departments. The same figures for patients receiving dextran or acetylsalicylic acid therapy were 3-8%. The limiting value for the P-coagulation factors II, VII and X for employing EA and SA varied considerably in the departments questioned. EA and SA were, however, contraindicated in patients receiving regular anticoagulation in the majority of departments. On a national basis, only two confirmed cases of symptom-producing haemorrhage in the spinal canal which could be attributed to thrombosis prophylaxis after SA/EA have been recognized. Both of these developed after regular anticoagulation therapy. The authors do not find any basis for warning against use of EA/SA in patients receiving subcutaneous heparin therapy, dextran or acetyl salicylic acid, unless another predisposition to haemorrhage is present.

Total i.v. anaesthesia with propofol-alfentanil or propofol-fentanyl.

In combination with propofol, alfentanil was compared with fentanyl for total i.v. anaesthesia in 29 women (ASA classes I, II) admitted for elective hysterectomy. Infusion rates of propofol and fentanyl were determined from the literature and from pilot studies, while alfentanil was given according to a computer program. Dosage was: propofol, bolus 1.5 mg kg-1, infusion 9 mg kg-1 h-1 for 10 min and thereafter 6 mg kg-1 h-1; fentanyl, bolus 7.5 micrograms kg-1, infusion 15 micrograms kg-1 h-1 reduced successively to 1.8 micrograms kg-1 h-1; alfentanil, bolus 60 micrograms kg-1, infusion 240 micrograms kg-1 h-1 reduced successively to 100 micrograms min-1. Induction was smooth and maintenance easy to manage in both groups. Plasma concentrations were stable with a ratio of alfentanil to fentanyl of 100:1. Recovery times were equal and short, but recovery tests performed 3 h after operation showed that alfentanil produced a greater effect on ability to concentrate and fine co-ordination.

[Pre-hospital care]. / Praehospital behandling.

Organisatory and therapeutic characteristics for selected pre-hospital medical treatment systems are described. It is emphasized that all of the links in the therapeutic chain must function optimally to achieve effective treatment of acute disease and injuries. The importance of rapid decision-making by highly qualified medical staff is emphasized. On the basis of experience from Denmark and from abroad, a model for up-to-date pre-hospital treatment in Denmark is outlined.

ARDS after accidental inhalation of zinc chloride smoke.

Five soldiers were injured by inhalation of hexite smoke (ZnCl2) during military training. Two soldiers, not wearing gas masks breathed hexite for 1 or 2 min, they slowly developed severe adult respiratory distress syndrome (ARDS) over the ensuing 2 weeks. This slow, progressive clinical course has not been previously described. In both patients, an increased plasma zinc concentration was measured 3 weeks after the incident. Intravenous and nebulized acetylcysteine increased the urinary excretion of zinc, and briefly decreased the plasma levels. In an attempt to arrest collagen deposition in the lungs, L-3,4 dehydroproline was administered. Both patients died of severe respiratory failure (25 and 32 days after inhalation). At autopsy diffuse microvascular obliteration, widespread occlusion of the pulmonary arteries and extensive interstitial and intra-alveolar fibrosis was observed. Three soldiers wearing ill fitting gas masks, immediately developed severe coughing and dyspnea. They improved, and 12 months after exposure their lung function tests were nearly normal, but they still had slight dyspnea on exercise.

Haemodynamic effects of intravenous procaine as a supplement to general anaesthesia in patients with valvular heart disease.

The effect of intravenous procaine, 2 mg/kg/min, on the cardiovascular function of nine patients scheduled for cardiac valve replacement was studied under enflurane-pancuronium anaesthesia. Procaine infusion was started after intubation during steady-state anaesthesia, and continued until start of cardiopulmonary by-pass. Systemic vascular resistance decreased steadily from 198.2 +/- 28.7 to 133.0 +/- 17.2 kPa X s/l (P less than 0.05). A simultaneous decline in mean arterial pressure from 10.13 +/- 0.68 to 7.47 +/- 0.48 kPa was observed (P less than 0.01). Cardiac index, heart rate, central venous pressure, pulmonary arterial mean pressure and pulmonary capillary wedge pressure were all unaffected by procaine as well as by surgical stimulation. It is concluded that continuous procaine infusion as an adjuvant to general anaesthesia effectively abolishes the hypertensive and tachycardiac response to surgical stimulation. The limiting factor in the amount of infused procaine appears to be the hypotension caused by vasodilation, not myocardial depression or convulsions.

Psychomimetic reactions after low-dose ketamine infusion. Comparison with neuroleptanaesthesia.

Low-dose ketamine anaesthesia was compared with neuroleptanaesthesia, in respect of immediate and longer-term psychomimetic reactions, in 40 female patients undergoing elective gynaecological surgery. Qualitatively, but not quantitatively, different psychomimetic reactions occurred in both groups. In the neurolept group the predominant complaint was of a dissociative nature, reported after 24 h by 11 (55%) of the patients, while in the ketamine group the predominant experience was dreaming, reported by eight (40%) of the patients after 24 h. Interviews after 3 months revealed a low frequency of psychomimetic reactions in both groups. However, 30% of all the patients (12) complained of impairment of intellectual function, and in seven patients this was severe enough to interfere with their ability to work.

Pulmonary angiotensin II production in respiratory failure.

Plasma angiotensin II concentration gradients across the pulmonary vascular bed, plasma renin concentration and serum converting enzyme activity were measured in 19 patients. The majority of the patients were critically ill. Nine patients had septicemia with acute respiratory failure, six patients had severe chronic lung disease and four patients had other serious disorders requiring haemodynamic monitoring. Pulmonary angiotensin II generation rates were calculated as the products of the pulmonary plasma flow and the angiotensin II concentration gradient across the lung. Several patients had a highly activated renin-angiotensin system. There was a strictly linear correlation between the plasma angiotensin II concentrations in mixed venous blood and in systemic arterial blood across a wide range, the concentration in arterial blood being 1.4-1.5 times that in mixed venous blood in each of the three groups of patients. Serum converting enzyme activity was not different from the level observed in a group of control patients above 50 years of age, but lower than in younger normal individuals. The maximal angiotensin II production rates in the pulmonary vascular bed of patients with life-endangering pulmonary disease were similar to the rates previously measured in hypertensive patients with renovascular or renal parenchymal disease. In conclusion, the process of angiotensin I conversion in the lung operates without impediment in spite of severe pulmonary injury.

Effects of low-dose ketamine and thiopentone on cardiac performance and myocardial oxygen balance in high-risk patients.

Induction of anaesthesia may pose a significant hazard to patients with critical cardiovascular status. Ketamine has been advocated as the drug of choice for maintaining cardiovascular performance during induction of anaesthesia in severely ill surgical patients. The purpose of this study was to compare the relative changes in the haemodynamic effects of ketamine and thiopentone during the first 30 min of anaesthesia induction measured by thoracic impedance cardiography. Twelve adult high-risk surgical patients, ASA class III-V, were induced with thiopentone and fentanyl or with infusion of ketamine. Cardiac output decreased to 69% in the thiopentone group (P less than 0.05), but was hardly affected in the ketamine group. The pre-ejection period to left ventricular time (PEPI) and the pre-ejection period index ratio increased significantly after thiopentone (P less than 0.05), while ketamine caused only minimal changes in left ventricular performance. The diastolic pressure time index to systolic pressure time index ration decreased significantly in both groups.

Cardiovascular haemodynamics during enflurane-pancuronium anaesthesia in patients with valvular heart disease.

The effects of enflurane-pancuronium anaesthesia on cardiovascular haemodynamics were studied before operation in six patients with valvular heart disease. A ten per cent decline in cardiac index and a 20 per cent decline in stroke volume were the only changes observed. Mean arterial, pulmonary arterial, contral venous, and pulmonary capillary wedge pressures were unaffected, as were systemic vascular resistance and pulmonary vascular resistance. The authors therefore conclude that enflurane-pancuronium anaesthesia causes only minimal cardiovascular depression in patients with valvular heart disease.