Stress response and platelet function in minor surgery during epidural bupivacaine and general anaesthesia: effect of epidural morphine addition

In a randomized study, thirty patients submitted to transarthroscopic meniscectomy were allocated to general or epidural anaesthesia with or without epidural morphine. Threshold concentration of collagen for platelet aggregation did not differ between the groups, but showed a similar pattern of increase, which was significant in the general anaesthesia group. Collagen-induced thromboxane-B2 synthesis was significantly lower in the epidural anaesthesia groups compared with the general anaesthesia group, and the addition of morphine caused a significant fall in thromboxane-B2 synthesis. The mean serum cortisol concentration increased in the general anaesthesia group, and decreased in the epidural groups. The difference between the groups was significant. Epidural morphine administration significantly decreased serum cortisol. During operation a thigh tourniquet was used. The removal of the tourniquet did not influence any of the measured variables. It can be concluded that the adrenocortical system is activated during general and inhibited during epidural anaesthesia. The addition of morphine during epidural anaesthesia further decreases the activity of the adrenocortical system, and the combined regime has an inhibiting effect on platelet function.     

Femoral shaft fracture after hip arthroplasty

Femoral shaft fractures after hip arthroplasties were treated in 74 noncemented hemiarthroplasties and 65 cemented arthroplasties. In loose prostheses the best clinical results and the least number of operations were achieved with revision arthroplasty with a long-stem prosthesis, combined with simple internal fixation methods when applicable. In firmly fixed prostheses the results of revision arthroplasty and traction treatment were similar. Cemented revision arthroplasty did not interfere with fracture union. Internal fixation with the prosthesis in situ cannot be recommended because of a large number of secondary revision arthroplasties and nonunions. Removal of the femoral stem prosthesis and internal fixation nearly always require a secondary revision and cannot be recommended.     

Incision and drainage v. incision, curettage and suture under antibiotic cover in anorectal abscess. A randomized study with 3-year follow-up

Conventional incision and drainage was compared with incision plus curettage and primary suture of abscess cavity under antibiotic cover in a prospective, randomized trial of 83 patients with acute anorectal abscess with or without low fistula. All the patients were followed up for three years. The time to healing was on average three weeks less after suture than after incision alone. The difference was statistically significant. Primary healing was obtained in 32 of 42 cases after suture. Recurrence of abscess tended to be more frequent after suture, but the time to healing of initial and recurrent abscesses and fistulas in the three-year observation period continued to be three weeks less after suture than after incision alone, making suture the most attractive treatment.     

A physiologic comparison of external cardiac massage techniques

On the basis of recent investigation, controversy has arisen regarding which of several cardiopulmonary resuscitation methods optimizes hemodynamics. The present study was designed to compare five recently described chest compression techniques: high-impulse manual chest compression at 150/min, mechanical compression at 60/min with simultaneous ventilation, mechanical compression at 60/min with simultaneous ventilation and either systolic or diastolic abdominal compression, and pneumatic vest compression at 60/min. Eight dogs were chronically instrumented with electromagnetic flow probes in the ascending and descending aorta while matched micromanometers measured aortic, left ventricular, and pleural pressures. At study, each dog was anesthetized with morphine, intubated, and the heart was fibrillated by rapid ventricular pacing. The five cardiopulmonary resuscitation methods were performed randomly in each preparation within 7 to 10 minutes of arrest. In four dogs, brachiocephalic blood flow was computed as total cardiac output minus descending aortic blood flow, and in all dogs coronary perfusion pressure was calculated as mean diastolic aortic pressure minus mean diastolic left ventricular pressure. Average cardiac output for seven studies was 662 +/- 61 ml/min with high-impulse manual compression, 340 +/- 46 ml/min with mechanical compression and simultaneous ventilation, 336 +/- 45 ml/min with mechanical compression and simultaneous ventilation with systolic abdominal compression, 366 +/- 52 ml/min with mechanical compression and simultaneous ventilation with diastolic abdominal compression, and 196 +/- 29 ml/min with vest resuscitation (high-impulse manual compression significantly greater than other techniques by multivariate analysis, p less than 0.05). Brachiocephalic blood flow generally followed cardiac output and was statistically the greatest with high-impulse manual compression at 273 +/- 47 ml/min (p less than 0.05). Finally, high-impulse manual compression provided the highest coronary perfusion pressure of 31 +/- 4 mm Hg (p less than 0.05) compared to 23 +/- 2 mm Hg for mechanical compression and simultaneous ventilation, 23 +/- 2 mm Hg for mechanical compression and simultaneous ventilation with systolic abdominal compression, 23 +/- 3 mm Hg for mechanical compression and simultaneous ventilation with diastolic abdominal compression, and 11 +/- 2 mm Hg for vest resuscitation. These data demonstrate that high-impulse manual compression generated physiologically and statistically superior hemodynamics when compared with other methods in this model of cardiopulmonary resuscitation.     

Amiodarone-mediated increase in intracellular free Ca2+ associated with cellular injury to human pulmonary artery endothelial cells

The cardiac antidysrrhythmic drug amiodarone can give rise to potentially fatal pulmonary toxicity in large numbers of patients. The effect of amiodarone on Ca2+ homeostasis and cell injury has been studied using human pulmonary artery endothelial (HPAE) cells in vitro. Amiodarone produced a concentration-dependent increase in intracellular free Ca2+ concentration ( [Ca2+]i) to micromolar levels that are similar to those seen with physiological stimuli that increase [Ca2+]i. Unlike physiological stimuli, the rise in [Ca2+]i produced by amiodarone developed slowly and was maintained over at least 30 min. Omitting Ca2+ from the external medium reversibly prevented the amiodarone-induced rise in [Ca2+]i. Amiodarone treatment increased the apparent first order rate constants for 45Ca2+ influx and efflux in intact HPAE cells. 45Ca2+ accumulation into the endoplasmic reticulum of saponin-permeabilized HPAE cells was decreased by amiodarone treatment. The release of 45Ca2+ from the endoplasmic reticulum stores by the putative intracellular second messengers inositol-1,4,5-trisphosphate, arachidonic acid, and Ca2+ was blocked by amiodarone treatment. The changes in Ca2+ homeostasis coincide with an increase in [3H]deoxyglucose release as a measure of early cell injury by amiodarone. It is concluded that amiodarone can produce an increase in [Ca2+]i by an action on the plasma membrane that allows the influx of external Ca2+. This increase in [Ca2+]i, together with other changes in Ca2+ homeostasis, may be responsible for the early cell injury associated with amiodarone toxicity.