Coagulopathy induced by haemodilution with either HES 200/0.5, HES 130/0.4, and dextran 70 may be improved by fibrinogen supplementation.

One hundred patients aged 18-49 yr, undergoing elective arthroscopy of the knee joint, were allocated randomly to either spinal anaesthesia using a 29-gauge spinal needle or general anaesthesia. Dural puncture was considered difficult in 18% of the patients receiving spinal anaesthesia. In three patients (6%) it was necessary to supplement the spinal anaesthetic with general anaesthesia. Spinal and general anaesthesia were otherwise uneventful in all patients. The incidence of postoperative headache was similar in the two groups. One patient developed post dural puncture headache following spinal anaesthesia. This headache was of short duration and disappeared without treatment. Spinal anaesthesia caused more backache than general anaesthesia, otherwise the frequency of postoperative complaints was the same or lower. Ninety-six percent of the patients receiving spinal anaesthesia would prefer the same anaesthetic for a similar procedure in the future.

Subhypnotic doses of thiopentone are considered to have a hyperalgesic effect, while propofol has a hypoalgesic effect. We investigated the effect of these drugs on the nociceptive system by measuring the pain threshold to laser stimulation and the pain evoked potential (power and latency). Nineteen patients (ASA group I) participated. Twelve patients received thiopentone 0.5 mg kg-1 and propofol 0.25 mg kg-1 in random order separated by an interval of 14 h, and seven patients received saline. Immediately after the injection of both agents, the pain threshold was increased significantly (P less than 0.001) and the amplitude of the evoked potential was reduced significantly (P less than 0.05), while the latency of the evoked potential remained constant. It is concluded that, in subhypnotic doses, both thiopentone and propofol decrease the acute pain evoked by argon laser stimulation.

Subhypnotic doses of thiopentone are considered to have a hyperalgesic effect, while propofol has a hypoalgesic effect. We investigated the effect of these drugs on the nociceptive system by measuring the pain threshold to laser stimulation and the pain evoked potential (power and latency). Nineteen patients (ASA group I) participated. Twelve patients received thiopentone 0.5 mg kg-1 and propofol 0.25 mg kg-' in random order separated by an interval of 14 h, and seven patients received saline. Immediately after the injection of both agents, the pain threshold was increased significantly (P < 0.001) and the amplitude of the evoked potential was reduced significantly (P < 0.05), while the latency of the evoked potential remained constant. It is concluded that, in subhypnotic doses, both thiopentone and propofol decrease the acute pain evoked by argon laser stimulation.

In 20 patients a continuous block of the lumbar plexus was administered after knee-joint surgery, and the analgesic effect of two different concentrations of bupivacaine was compared. The same volume of bupivacaine was given to both groups of patients: a bolus dose of 0.4 ml/kg, 0.5% or 0.25%, followed by infusion of 0.14 ml/kg/h, 0.25% or 0.125%, respectively, via a catheter placed in the neurovascular fascial sheath of the femoral nerve according to the "3-in-1 block" technique. The median morphine consumption during the first 16 h postoperatively was 6.0 mg when bupivacaine 0.5/0.25% was used and 9.5 mg when 0.25/0.125% was used. This difference is not significant. The visual analogue pain scores were also similar in the two groups (P greater than 0.05). All plasma concentrations were below 4 micrograms/ml, the highest concentration measured being 3.6 micrograms/ml. It is concluded that when used for a continuous block of the lumbar plexus after knee-joint surgery, bupivacaine in a concentration of 0.125% offers the same pain relief as a concentration of 0.25%, and the risk of toxic reactions is reduced.

In conclusion, our study demonstrated that renal function, assessed by GFR and ERPF, is transiently reduced during the combination of hypotensive anaesthesia and acute normovolaemic haemodilution. A colloid-based fluid regime (HES 130/0.4) used for haemodilution may preserve renal function to a greater extent than a crystalloid-based regime (0.9% saline).

The fentanyl iontophoretic transdermal system and morphine intravenous patient-controlled analgesia are comparably well tolerated and effective methods of pain control, regardless of sex, American Society of Anesthesiologists physical status or the type of anaesthesia used for surgery, and following most surgery types.

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