Daily SOAP

Ohne Zusammenfassung     

Pathophysiological and clinical aspects of the CO2 pneumoperitoneum (CO2-PP)

Experimental studies demonstrated a severe cardiac load of the CO₂ pneumoperitoneum caused by an accelerated after- and a decreased preload. Patients displaying cardiovascular risks are therefore often rejected from laparoscopic surgery. Hence, the pathophysiological changes and the intraoperative risk of the CO₂ pneumoperitoneum in high-risk cardiopulmonary patients (NYHA II–III, n= 15) undergoing laparoscopic cholecystectomy are described. The changes in cardiac after- and preload seem to be due to the elevated intraabdominal pressure rather than transperitoneally resorbed CO₂ and are reversible by desufflation. In one patient conversion to open operation had to be performed because of a severe drop in cardiac output and right ventricle ejection fraction. Mixed oxygen saturation was predicting intraoperative worsening in this case. The described pathophysiological changes may seem to be well tolerated even in high-risk cardiac patients. Monitoring of hemodynamics should include an arterial catheter line and blood gas analyses. Pharmacologic interventions or pressureless laparoscopic procedures might not be necessary as long as laparoscopic cholecystectomy is performed. Received: 13 December 1996/Accepted: 8 January 1997     

Sind „Linkshänder” bessere Lokalanästhetika? Zur Relevanz der Stereoisomerie in der klinischen Praxis am Beispiel neuer Lokalanästhetika

S-Ropivacaine is a new, long-acting amide local anaesthetic. It is the first local anaesthetic to be on the market as a single isomer. Its pharmacodynamic and pharmacokinetic profile is similar to that of bupivacaine. In vitro and in vivo experiments have shown ropivacaine to be less cardiotoxic than bupivacaine. When given epidurally, both local anaesthetics are equally effective in producing sensory block, but motor block seems to be less pronounced in the case of ropivacaine. This pharmacodynamic profile suggests that ropivacaine has a greater margin of safety and should be a valuable candidate in applications where motor blockade is to be avoided, e.g. for postoperative epidural analgesia and for epidural analgesia in obstetrics.     

Frühgeburt und Grenzen

Ohne Zusammenfassung     

Erythropoietic protoporphyria and pretransplantation treatment with nonbiological liver assist devices.

Erythropoietic protoporphyria (EPP) is a disease of the heme metabolism due to a deficiency of ferrochelatase, leading to accumulation of protoporphyrin (PPIX) in the erythrocyte (red blood cell [RBC]). The major clinical manifestation in EPP is photosensitivity; however, in a small number of patients liver failure is a significant complication and liver transplantation is the only treatment option. Damage to both abdominal skin and organs occurs when exposed to operating light; however, this problem can be ameliorated by the use of filters that block the transmission of light with wavelength below 470 nm. A more unusual but very serious complication postoperatively is severe motor neuropathy, with few or no known acute available precautions. An effective treatment option is needed to manage EPP crises and to prevent complications after liver transplantation. We successfully treated a patient with EPP-induced liver failure with the molecular adsorbents recirculating system (MARS) and Prometheus in independent sessions. Following treatment with MARS we found a 9.1% reduction of the RBC-PPIX concentration and a 5.9% reduction after treatment with the Prometheus system. Plasmapheresis made a reduction in RBC-PPIX concentration of 0.8%. Following treatment sessions with MARS and Prometheus, the clinical condition was markedly improved and orthotopic liver transplantation was performed without further complications. In conclusion, extracorporeal therapy with MARS or Prometheus seems to be efficient in reducing RBC-PPIX concentration in comparison to plasma exchange.     

Safety and efficacy of radiofrequency ablation of brain: a potentially minimally invasive treatment for brain tumours.

INTRODUCTION: Cerebral metastases are associated with a very poor prognosis. The best survival results are seen after surgical resection. However this involves a relatively invasive procedure and many patients are not suitable for surgical resection. We have evaluated the safety and efficacy of radiofrequency ablation of the brain in a sheep model. METHODS: We produced ablations of 1 - 3 cm diameter in the brain of sheep using the RITA starburst XL probe and RITA 1500 generator. We varied the time of RF application between 1 minute and 5 minutes and observed the animals for between 24 hours and 3 weeks for short-term and long-term effects and measured the intracranial pressure (ICP) in 2 animals following RFA. RESULTS: A total of 8 ablations were produced in 8 sheep. There was no change in the ICP measurements and there were no neurological complications in the 5 sheep with superficial ablation of up to 2 cm. Three sheep failed to regain consciousness due to large ablations near the brain stem and cerebellum. The sizes of the ablations were confirmed on necropsy and there was no other evidence of damage to the surrounding brain. Satisfactory ablation of brain was achieved at 70 degrees C and an ablation time as short as 3 minutes produced a 1.5 - 2.0 cm diameter of ablation. CONCLUSION: Cerebral RFA is a relatively safe and effective technique capable of producing a predictable ablation with no damage to surrounding brain. The potential of this technique requires further evaluation but likely advantages include the ability to treat multiple tumours and perform repeated treatment with a minimally invasive approach.