Sedative-analgesic treatment of patients on long-term artificial ventilation 
aims at protection from stress related to their disease or therapy. By 
stabilising both the patient's vital functions and psychological state this 
treatment may contribute to therapeutic success. The choice of drugs depends 
primarily on the nature and course of the underlying disease. Midazolam and 
propofol are available as hypnotics for short-term sedation during the 
post-operative period. The purpose of this study was to evaluate the effects of 
both agents on cardiovascular function, cortisol production, lipometabolism, and 
the recovery period following 24-h sedation. METHODS. Twenty female patients 
(mean body weight: 72 kg, mean age: 60 years) were randomly assigned to receive 
either midazolam or propofol over 24 h following major abdominal surgery. 
Balanced anaesthesia (halothane/O2/N2O/fentanyl) was administered for the 
surgical procedure. Assisted ventilation was used in all patients during the 
post-operative sedation period. Sedation depth was maintained at III-IV on the 
Ramsey scale. On arrival in the intensive care unit (ICU), an initial i.v. bolus 
of midazolam 0.1 mg/kg or propofol 1 mg/kg was followed by a continuous infusion 
(midazolam: 0.1 mg/kg.h; propofol: 2 mg/kg.h). Supplementary boluses of one-half 
the initial dose were given if required. Post-operative analgesia was achieved 
with 3 mg intravenous piritramide at 2-h intervals. A 7F Swan-Ganz catheter was 
inserted in the pulmonary artery and haemodynamic and biochemical parameters 
were monitored at 4-h intervals over 24 h starting 2 h after arrival in the ICU. 
Catecholamines were measured by high-pressure lipid chromatography (HPLC), 
cortisol by radioimmunoassay, midazolam by HPLC and ultraviolet detection, and 
propofol by HPLC and fluorescence detection. Data were calculated as means. The 
statistical analysis was performed according to the Mann-Whitney test, and 
significance was accepted for P less than 0.05. RESULTS. On administration of 
the propofol bolus at the onset of sedation, a decrease in blood pressure was 
particularly observed in patients with masked hypovolaemia, however, this 
decrease was easily controlled by volume administration. Independent of the type 
of sedation, the haemodynamic parameters remained unchanged throughout the 
observation period. At all times of measurement the mean heart rate was lower in 
the propofol group (90/min) when compared with the midazolam group (100/min), 
however, this difference did not reach significance. There were also no 
significant differences in cardiac index at all times of measurement, although 
it increased in both groups within the first 12 h by 0.6 l/min.min2. In both 
groups this increase was associated with a reduction in peripheral resistance 
and an increase in rectal temperature. To achieve the desired sedation depth, 
midazolam was administered at a mean dosage of 0.11 mg/kg.h and propofol at 1.9 
mg/kg.h. Catecholamine levels decreased in both groups within the first 8 h: 
after 8 h of sedation the plasma levels of noradrenaline and adrenaline were 525 
and 65 pg/ml, respectively, in the midazolam group and 327 and 51 pg/ml in the 
propofol group. (ABSTRACT TRUNCATED AT 400 WORDS)