Contained rupture of the aorta in acute Stanford type A aortic dissection causing right ventricular wall dissection.

We describe a rare case of an acute aortic type A dissection after previous aortic valve replacement and coronary artery revascularization complicated by a contained rupture and right ventricular wall dissection. Although preoperatively echocardiography and CT scan described a pericardial hematoma, intraoperatively no intrapericardial hematoma was found; instead an extended right ventricular wall dissection caused by a large thrombus formation within the right ventricular muscle layers was demonstrated. After replacement of the ascending aorta and removal of the thrombus as the sole treatment for right ventricular wall dissection, the two dissected layers of the right ventricular wall were contracting synchronously again.

Aortic valve leaflet reconstruction after excision of a papillary fibroelastoma using autologous pericardium.

We report on a case of a rare tumor attached to the nodulus arantii of the left coronary cusp in a 56-year-old female patient. She was referred to our institution for a non-ST elevation myocardial infarction after a troponin-positive test. Diagnosis was made by echocardiography and confirmed by surgery. After complete surgical removal of the tumor, we reconstructed the left coronary cusp with autologous pericardium. Aortic valve cusp coaptation could be completely restored. Histology revealed the diagnosis of a papillary fibroelastoma.

Plasma level changes of fentanyl and midazolam after release of a prolonged thigh tourniquet.

In 14 elderly orthopedic patients undergoing total knee joint replacement, the influence of complete arterial occlusion of the limb on the course of plasma levels of fentanyl and midazolam was examined. The patients were premedicated with midazolam intramuscularly (0.05 mg/kg) and were then given neurolept anesthesia in dosages of 0.1 mg/kg midazolam and 0.01 mg/kg fentanyl intravenously prior to the placement of the tourniquet. Up to 4 h after the tourniquet was released, plasma levels of fentanyl and midazolam as well as pH value, PaCO2 and plasma lactate levels were measured. In 12 patients there was an increase in fentanyl and in 10 patients an increase in midazolam plasma levels after tourniquet release. The maximum increase varied between 1 min and 2 h after release. The plasma levels of midazolam after removal of the tourniquet varied greatly between individuals. Especially patients older than 70 years showed excessively high concentrations of midazolam. These results would indicate that there can be a clinically significant increase of fentanyl and midazolam levels due to initial reperfusion of the lower extremity following prolonged ischemia. Therefore a correspondingly extended period of postoperative surveillance is advisable.

[The effect of a thigh tourniquet on the pharmacokinetics of midazolam]. / Auswirkungen eines Oberschenkel-Tourniquets auf die Pharmakokinetik von Midazolam.

Although the general pharmacokinetics of midazolam (M) are well documented, little is known about the possible effects of a thigh tourniquet on the distribution and elimination of this drug. METHOD. Institutional approval for the study and individual informed consent were obtained. We studied 30 patients (ASA-I) without premedication who electively underwent a surgical procedure of the lower limb. Patients were divided into three groups of 10. The procedure was done in groups I and II with and in group III without tourniquet use. Anesthesia was induced in groups I and II with 0.1 mg/kg M, fentanyl 5 micrograms/kg, alcuronium-dichloride 0.15 mg/kg and etomidate 0.1-0.2 mg/kg i.v. and maintained with enflurane 0.3-1.0 vol.-%. About 20 min after midazolam injection and after exsanguination the tourniquet was applied on the proximal thigh in group I. In group II anesthesia was induced with etomidate 0.2 mg/kg and alcuronium-dichloride 0.15 mg/kg i.v., and maintained about 20 min with enflurane 1.0-1.5 vol.-% until exsanguination and tourniquet application. After this, these patients also received 0.1 mg/kg M and 5 micrograms/kg fentanyl i.v. Through an indwelling arterial line, blood samples were obtained prior to and 2, 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165 and 180 min after M injection. Plasma M levels were measured by high-performance liquid chromatography with UV detection. These concentrations were fitted to a two-compartment open model. Comparison between groups was performed using the Kruskal-Wallis test and p less than 0.05 was considered to indicate significance. RESULTS. The groups were all comparable in age and weight, and groups I and II also in duration of thigh ischemia. Midazolam elimination half-time (t beta 1/2) was significantly shorter in group II than in groups III and I (52 min vs 126 min and 139 min; p less than 0.05). Of the calculated distribution volumes (volume of the central compartment, volume in the steady state and volume in the elimination phase), only the volume in the steady state was significantly smaller in group II than in groups III and I (p less than 0.05). Groups III and I did not differ significantly in the computed parameters. The measured initial midazolam mean concentrations in group II were twice those in groups III and I (655 ng/ml vs 323 ng/ml and 332 ng/ml). Since clearance was not significantly different between any two groups, the shorter t beta 1/2 in group II was probably due to the reduced distribution volume. CONCLUSION. These data demonstrate that in the presence of a thigh tourniquet the timing of the injection - before or after application of the tourniquet is of decisive importance. Injection after the application of a tourniquet leads to an higher plasma level and shortens the elimination half-life.