A comparison of superficial versus combined (superficial and deep) cervical plexus block for carotid endarterectomy: a prospective, randomized study.

Carotid endarterectomy may be performed by using cervical plexus blockade with local anesthetic supplementation by the surgeon during surgery. Most practitioners use either a superficial cervical plexus block or a combined (superficial and deep) block, but it is unclear which offers the best operative conditions or greatest patient satisfaction. We compared the two techniques in patients undergoing carotid endarterectomy. Forty patients undergoing carotid endarterectomy were randomized to receive either a superficial or a combined cervical plexus block. Bupivacaine 0.375% to a total dose of 1.4 mg/kg was used. The main outcome measure was the amount of supplemental lidocaine 1% used by the surgeon. Subsidiary outcome measures were postoperative pain score, sedative and analgesic requirements before and during surgery, and postoperative analgesic requirements. Median supplemental lidocaine requirements were 100 mg (range 30-180 mg) in the superficial block group and 115 mg (range 30-250 mg) in the combined block group. These differences were not statistically significant (Mann-Whitney U-test). There was no significant difference in the number of patients needing postoperative analgesia between the groups (11 of 20 in the deep block group versus 8 of 20 in the superficial block group) in the 24 h after surgery. The median time to first analgesia in the superficial block group was 150 min, more than in the combined block group (median time 45 min) but this difference, although large, was not statistically significant (Mann-Whitney U-test). We found no significant differences between the anesthetic techniques studied. All patients reported satisfaction with the techniques.

A cost analysis of alprostadil in liver transplantation.

Alprostadil (prostaglandin E1) administration to liver transplant recipients has been shown to result in a significant reduction in the duration of hospital admission for transplantation, and in the need for re-operations (other than re-transplants) and renal support. To study the economic impact of this finding, we examined data from a controlled trial for all single-transplant surviving patients (42 alprostadil, 49 controls) for whom complete billing records were available for transplant days -2 to +150. All costs were measured in 1992 US dollars. Patients given alprostadil had lower total charges [mean +/- standard deviation (SD) $US175 297 +/- $US70 652] than patients given placebo (mean +/- SD $US225 672 +/- $US187 208) [p = 0.043]. The data suggest that the use of alprostadil may have a significant favourable impact on the cost of liver transplantation.

A double-blind, randomized, placebo-controlled trial of prostaglandin E1 in liver transplantation.

A double-blind placebo-controlled trial of intravenous prostaglandin PGE1 (40 micrograms/h) was conducted in adult orthotopic liver transplant recipients. Infusion was started intraoperatively and continued for up to 21 days. Patients were followed up for 180 days postoperatively. Among 172 patients eligible for treatment in the study, 160 could be evaluated (78 PGE1; 82 placebo). Patient and graft survival were similar (PGE1: 16 deaths, 9 retransplantations [7 survivors]; controls: 15 deaths, 6 retransplantations [3 survivors]). In patients with surviving grafts, however, PGE1 administration resulted in a 23% shorter mean duration of hospitalization following transplantation (PGE1: 24.4 days; controls: 31.8 days; P = .02) and a 40% shorter length of time postoperatively in the intensive care unit (PGE1: 8.2 days; controls 13.7 days; P = .05). Reduced needs for renal support (P = .03) or surgical intervention other than retransplantation (P = .02) were also noted with PGE1 use. Further, PGE1 administration resulted in a trend toward improved survival rates in patients with mild renal impairment (preoperative serum creatinine 1.5 mg percent or greater; P = .08). Neither the incidence of acute cellular rejection nor of primary nonfunction was significantly different in the two groups. Phlebitis was the only complication that was more common during PGE1 administration, (PGE1: 9; controls: 4). These results suggest that PGE1 use in hepatic allograft recipients reduces morbidity and may result in sizable cost reductions.

Coagulation status during aortic aneurysm surgery: comparison of thrombelastography with standard tests.

A prospective comparison of thrombelastography to standard coagulation tests was undertaken in ten patients undergoing routine, uncomplicated abdominal aortic aneurysm surgery in order to explore potential clinical utility and establish normal patterns of change. Thrombelastograph k values increased (7.1 vs 5.4 min baseline, P < or = .01), and alpha angle (43 vs 52 degrees baseline, P < or = .001) and ma (39 vs 52 mm baseline, P < or = .01) values decreased following graft placement, while r values remained unaffected (6.4 vs 7.5 min baseline, P > .05). Weak correlations were observed between alpha angle and fibrinogen, prothrombin time, and partial thromboplastin time (aPTT), as well as between k and aPTT (0.70 < r < 0.79 for all). Systemic fibrinolysis was suggested by thrombelastography in 25% of samples, although euglobulin lysis times were abnormal in only 5% (chi 2 = 4.80, P < or = .05). Fibrin degradation product detection increased through the fifth postoperative day in all patients. Variations in thrombelastographic parameters and their correlation to standard coagulation tests in patients undergoing uncomplicated abdominal aortic aneurysm repair were documented. In such a setting, no clear advantages to thrombelastography were defined. Further observations will be necessary to establish the role for thrombelastography in the management of patients experiencing clinically significant perioperative coagulation disorders.

Iatrogenic lithotripsy failure: penetration of shock waves through tape.

Foam tape used to protect epidural catheters during immersion in a Dornier HM3 lithotriptor was identified retrospectively as the cause of poor stone fragmentation. Studies of shock wave penetration through various protective type materials indicate that a particular water repellant tape is least likely to impair shock wave penetration.

Effect of salbutamol and suxamethonium on the plasma potassium concentration.

In a double-blind randomized study, patients received premedication with lorazepam 0.04 mg kg-1 and salbutamol 0.1 mg kg-1 or lorazepam 0.04 mg kg-1 and placebo given orally 2.5-3 h before anaesthesia. The plasma potassium concentration was measured at the time of premedication, before the induction of anaesthesia and at selected intervals after suxamethonium 1 mg kg-1 i.v. The plasma potassium concentration was lower in those patients who received salbutamol than in those given placebo, and remained lower at all the subsequent sample times. Oral salbutamol did not appear to affect the incidence of suxamethonium related muscle pain.

Effects of the argon laser on anaesthetic gases and endotracheal tubes.

The effects of argon laser light on endotracheal tubes and gas mixtures have been studied. In recommended use accidental exposure to red rubber and PVC tubes caused minimal damage. Prolonged exposure of PVC tubing and a 2:1 nitrous oxide:oxygen mixture produced a minimal increase in temperature and no detectable increase in the concentration of higher oxides of nitrogen. Transparent endotracheal tubes are recommended if the argon laser is being used in the management of cutaneous lesions of the head and neck.