Computed tomography angiography (CTA) to prove circulatory arrest for the diagnosis of brain death in the context of organ transplantation.

QUESTION UNDER STUDY: For the determination of brain death (BD) in potential organ donors, confirmatory tests that show cessation of cerebral circulation are used in many countries. Conventional angiography is considered the golden standard among these ancillary examinations. In recent years other angiographic techniques such as CT angiography (CTA) have been increasingly employed to establish the diagnosis of BD. We report our experience with CTA in this setting. MATERIAL AND METHODS: From 2007 to 2010, 29 patients were examined in order to determine BD using CTA. The studies consisted of an unenhanced head scan, a CT angiogram of the brain supplying vessels in the head and neck and a second head scan 80 seconds after contrast injection (venous phase). The studies were retrospectively re-evaluated by two experienced neuroradiologists according to the criteria accepted by the Swiss Academy of Medical Sciences. RESULTS: In 22 patients, cessation of cerebral circulation was confirmed in the venous phase CT. In seven patients, cessation of brain circulation was not confirmed due to residual contrast enhancement in the relevant cerebral vessels, i.e. the M4-segments of the middle cerebral artery and/or the internal cerebral veins. In these patients, clinical re-evaluation after a minimum of six hours confirmed the diagnosis of BD. Using the clinical examination as the "golden standard," CTA achieved a sensitivity of 75.9%. CONCLUSION: CTA is a useful additional tool for the confirmation of the diagnosis of brain death. Pooling of contrast in the relevant cerebral vessels, however, can be detected in up to 25% of CTAs in clinically brain dead patients.

Determination of plasma volume by indocyanine green--validation of the method and use in patients after cardiopulmonary bypass.

OBJECTIVE: Validation of plasma volume (PV) determination by indocyanine green (ICG) in comparison to the gold-standard method with radioiodinated albumin, and investigation of the effect of commonly used plasma expanders (albumin, hydroxyethyl starch, and polygelatine) on PV in the early postoperative phase in patients undergoing cardiac surgery. DESIGN: Prospective clinical study. SETTING: Department of medicine and intensive care unit at a university hospital. PATIENTS AND PARTICIPANTS: Ten healthy volunteers and 21 patients after elective open-heart surgery. MEASUREMENTS AND RESULTS: PV of subjects was measured by i.v. injecting 5 microCi [125I]albumin (I-ALB). One hour later, PV was determined by a peripheral i. v. injection of 0.25 mg/kg body weight ICG (ICG1). In five subjects PV was measured repeatedly by ICG (ICG2) 1 h after ICG1. Mean PV of I-ALB and ICG1 or ICG2 showed consistent results. Further, we investigated central vs peripheral intravenous injection of ICG in six patients after open-heart surgery compared to [125I]albumin. There was no difference between mean PV measured by [125I]albumin and peripheral ICG (P = 0.40). PV determined by central injection of ICG was significantly higher than by the other methods. In 15 patients PV was determined by [125I]albumin. Thereafter, patients were randomly divided into three groups. Group ALB was infused with 1.75 ml/kg body weight human albumin 20%, group HAES with 5.25 ml/kg body weight hydroxyethyl starch 6%, and group HAEM with 7.0 ml/kg body weight polygelatine 3.5%. PV was measured 1 h and 4 h after infusion by ICG. There were no significant changes in PV between the groups. CONCLUSIONS: PV determination by peripheral i. v. injection of ICG produced reliable and consistent results when a reactive hyperaemia was produced by a tourniquet prior to injection. Therefore, central venous injection of ICG may not be prerequisite for precise measurements of PV. The expected acute increase in PV after infusion of commonly used plasma expanders after cardiac surgery was not found.

Validation of "nine equivalents of nursing manpower use score" on an independent data sample.

OBJECTIVE: To compare the recently developed "nine equivalents of nursing manpower use score" (NEMS) with the simplified Therapeutic Intervention Scoring System (TISS-28). DESIGN: Prospective single centre study. SETTING: Adult 30-bed medical-surgical intensive care unit (ICU) in a tertiary care university hospital. PATIENTS: Data from all patients admitted in 1997 to the ICU were included in the study. METHODS AND RESULTS: NEMS and TISS-28 items were recorded prospectively for each nursing shift. There were three shifts per day. The Simplified Acute Physiology Score (SAPS) II was calculated for the first 24 h of ICU stay and each patient's basic demographic data were collected. The agreement between NEMS and TISS-28 was assessed by calculating the mean difference and the standard deviation of the differences between the two measures. Further, regression techniques and Pearson's correlation were used. Altogether, 2743 patients with a total of 28,220 nursing shifts were included; 62% of the shifts were used for postoperative/trauma patients and 38% for medical patients. Mean NEMS was 26.0 +/- 8.1 and mean TISS-28 was 26.5 +/- 7.9. The scores differed by < or = 3 points in 49 % of all shifts. The bias was -0.5 +/- 5.3 (95% confidence interval -0.47 to -0.60) and the limits of agreement were -11.1 to +10.1. The relation between the two systems was NEMS = 4.7 +/- 0.8 x TISS-28 (r = 0.78, r2 = 0.62, p < 0.001). Including postoperative/trauma patients only: NEMS = 1.9 +/- 0.9 x TISS-28, for medical patients this equation was: NEMS = 6.0 + 0.8 x TISS-28. First-day SAPS II explained 11% of the variability in first-shift NEMS and 5% of the variability in first-shift TISS-28. CONCLUSIONS: This study confirms a good agreement between TISS-28 and NEMS in a large, independent sample. However, as shown by the differences between medical and postoperative/trauma patients, a change in case mix may result in different regression equations. Further, wide limits of agreement indicate that there may be a rather large variability between the two measures at the individual level.

Role of thromboxane and leukotriene B4 in patients with acute respiratory distress syndrome after oesophagectomy.

We have studied prospectively the clinical course and serum concentrations of thromboxane B2 (TxB2) and leukotriene B4 (LTB4) in patients developing adult respiratory distress syndrome (ARDS) after oesophagectomy. The clinical course was assessed according to a validated ARDS score, and intra- and postoperative measurements of TxB2 and LTB4 in pre- and post-pulmonary blood were performed in 18 patients undergoing oesophagectomy for oesophageal carcinoma and 11 control patients undergoing thoracotomy and pulmonary resection. Six of 18 patients undergoing oesophagectomy, but no control patient, developed ARDS. The ARDS score was highest on day 8 after operation. Only patients with ARDS had a significant postoperative increase in post-pulmonary, but not pre-pulmonary, TxB2 concentrations (P < 0.05 vs patients without ARDS). This study provides evidence that TxA2, originating from the lungs, was associated with the development of ARDS after oesophageal resection. In view of the high incidence of ARDS after oesophagectomy (10-30%), prophylactic treatment of patients undergoing oesophageal resection with clinically applicable thromboxane synthetase inhibitors may be warranted.

Long-term follow-up of patients with operative stabilisation of a flail chest.

The outcome is reported of patients after external chest wall stabilisation for respiratory insufficiency due to a traumatic flail chest. Since 1990, all patients with a flail chest causing respiratory insufficiency despite peridural analgesia and without further reason for prolonged mechanical ventilation underwent osteosynthesis of the chest wall using the AO-technique with 3.5 mm thick reconstruction plates, and were prospectively followed-up by use of clinical and radiological evaluation. 23 patients underwent external chest wall fixation between 1990 and 1996 and were followed for a mean time of 28 months. 2 patients died after the operation, giving a 30-day-survival rate of 91.3% 21 patients survived and were extubated and transferred to the ward after a mean time interval of 3.9 and 7.8 days, respectively. 95% of the survivors revealed a 100% working capacity at assessment and 86% returned to preoperative sports activities without complaining of chest wall or shoulder girdle pain or dysfunction. External chest wall fixation appears to be an attractive alternative to prolonged intubation and mechanical ventilation for selected patients with flail-chest respiratory insufficiency despite peridural analgesia, providing they do not require prolonged intubation for other reasons.

[Effect of postoperative retransfusion of autologous blood products on hemostasis in heart surgery]. / Einfluss der postoperativen Retransfusion von autologen Blutprodukten auf die Hämostase in der Herzchirurgie.

In cardiac surgery a reduction of homologous blood products is mainly achieved by autologous blood salvage. Unprocessed retransfusion of autologous blood may induce changes in hemostasis. We assessed changes of activated clotting times (ACT) after retransfusion of unprocessed (1) oxygenator blood and (2) shed mediastinal blood. In 41 patients undergoing cardiac surgery (37 revascularization and 4 valve procedures) with a mean cardiopulmonary bypass time of 116.3 min, ACT was measured at the following time points: pre- and postoperatively, and before and after retransfusion of oxygenator blood and shed mediastinal blood. A significant prolongation of ACT values was only seen between pre- to postoperative blood (p < 0.003). Retransfusion of oxygenator blood changed ACT from 120 +/- 25 vs 116 +/- 17 sec and retransfusion of shed mediastinal blood showed a mean ACT of 118 +/- 14 vs 115 +/- 20 sec from before to after transfusion. There was a significant correlation between the ACT value in the unprocessed oxygenator blood and the ACT value measured in the patient after retransfusion (r = 0.41, p < 0.02). 6 patients receiving over 1 litre of unprocessed autologous blood (either from the oxygenator or the mediastinum) in less than 60 minutes showed a significant increase of ACT value after transfusion (p < 0.05). Hence, under normal conditions, retransfusion of unprocessed autologous blood will not significantly alter hemostasis measured by the ACT test in patients undergoing cardiac surgery.

[Secondary peritonitis after negative computerized tomography in blunt abdominal trauma]. / Sekundäre Peritonitis nach negativem Computertomogramm (CT) beim stumpfen Abdominaltrauma.

Diagnostic peritoneal lavage has widely been replaced by emergency sonography in the evaluation of blunt abdominal trauma. CT is generally performed in cases without major hemodynamic instability in order to define non-operative treatment of injuries of the parenchymatous organs or to precise the extension of retroperitoneal, spinal and pelvic lesions. Despite the good results of this method for the mentioned indications, the low sensitivity of CT for lesions of hollow viscus should not be forgotten. We report 3 cases of lesions of the small bowel (2 perforations and 1 mesenteric lesion with ischemic bowel wall) which were not visible, even retrospectively, at the CT. Despite discrete clinical signs, these lesions were only diagnosed at the stage of obvious secondary peritonitis. These cases should remind us the limits of CT in the evaluation of abdominal visceral lesions in blunt trauma.