[Preoperative autologous blood donation in cardiac surgery. Reduction of allogeneic blood requirements]. / Präoperative Eigenblutspende in der Herzchirurgie. Reduzierung des Fremdblutverbrauches.

BACKGROUND: Preoperative autologous blood donation is an effective method to reduce allogeneic transfusion requirement. However, this method is only rarely utilized in cardiac surgery. Besides economic concerns one essential argument against predonation is the lack of sufficient time due to the short waiting lists. The aim of the present study was to investigate the efficacy of autologous predonation to reduce allogeneic blood transfusion in routine cardiac surgery on a center without longer preoperative waiting lists. PATIENTS AND METHODS: A total of 2,626 cardiac surgery patients were included. Primary endpoint of the study was the perioperative incidence of allogeneic packed cell transfusion. If time between diagnosis and admission to the hospital was >10 days, predonation was offered to the patients. Data were stratified for preoperative risk score. Logistic and linear regression analysis tested the influence of different variables on the incidence of allogeneic blood transfusion and the total amount of allogeneic blood. RESULTS: Of all patients 267 (11.2%) underwent predonation. The incidence of allogeneic packed cell transfusion was reduced from 53% to 19% by autologous predonation (p<0.001). The total amount of allogeneic blood transfused was significantly different between the groups (2.2+/-4.2 vs. 0.84+/-6.3 units; p<0.001). DISCUSSION: Autologous predonation in cardiac surgery was effective in reducing blood transfusions even in the absence of longer preoperative waiting times. It is a safe and effective method to minimize blood transfusion in cardiac surgery.

Preanesthetic train-of-four fade predicts the atracurium requirement of myasthenia gravis patients.

BACKGROUND: The most sensitive diagnostic criterion of myasthenia gravis is a decrement in the muscular response to repetitive stimulation. The authors hypothesized that myasthenia gravis patients who show a train-of-four ratio (T4/T1) < 0.9 in the preanesthetic period will have increased sensitivity to nondepolarizing neuromuscular blocking agents compared with myasthenia gravis patients with preanesthetic T4/T1 > or = 0.9. METHODS: After institutional review board approval was obtained, 20 electrophysiologically documented myasthenia gravis patients were studied. Current pyridostigmine therapy was continued until the morning of surgery. Before induction of anesthesia, neuromuscular transmission was recorded from the hypothenar muscles using electromyography with train-of-four stimulation of the ulnar nerve. According to the T4/T1 ratio, patients were assigned to the "normal" group (T4/T1 > or = 0.9) or the "decrement" group (T4/T1 < 0.9). After induction of intravenous anesthesia, the effective dose to achieve a 95% neuromuscular blockade (ED95) for atracurium was assessed with a cumulative bolus technique. Postoperatively, pyridostigmine was titrated to obtain a T4/T1 > 0.75 and to treat residual myasthenic symptoms. RESULTS: In 14 patients, preanesthetic T4/T1 was > or = 0.9 (normal), whereas 6 patients presented with T4/T1 < 0.9 (decrement). Decrement patients had a lower ED95 of 0.07 +/- 0.03 mg/kg atracurium (mean +/- SD) compared with normal patients with an ED95 of 0.24 +/- 0.11 mg/kg atracurium (P = 0.002). All patients were extubated within 30 min after surgery. Postoperative pyridostigmine infusion did not differ significantly between groups. CONCLUSIONS: The requirement for atracurium is significantly reduced in myasthenia gravis patients with a T4/T1 ratio < 0.9 before anesthesia. This study indicates that routine neuromuscular monitoring in myasthenia gravis patients should be extended into the preinduction period to identify patients who require less atracurium.

[Neuromuscular recovery following mivacurium is predictable in patients with severe systemic disease prognoses]. / Die neuromuskuläre Erholung nach Mivacurium lässt sich auch bei Patienten mit schweren Begleiterkrankungen prognostizieren.

OBJECTIVES: Fast recovery from mivacurium-induced neuromuscular blockade is impaired in patients with decreased plasma cholinesterase activity which is often associated with dysfunction of different organs. Nevertheless, predictability of neuromuscular recovery may be given. Thus, this study evaluates parameters to predict individual neuromuscular recovery in patients with uncommon diseases. METHODS: 84 male or female patients (18-70 years of age) were allocated to one of two groups according to their ASA risk profile (without severe systemic diseases: ASA 1 and 2; with severe systemic diseases: ASA 3 and 4). Plasma cholinesterase activity (PChE) had been determined preoperatively. Anaesthesia was performed with propofol and fentanyl. Neuromuscular transmission was monitored by electromyography. The ulnar nerve was stimulated by train-of four stimuli and neuromuscular transmission was measured at the hypothenar. After mivacurium 0.1 mu mg/kg, an infusion of mivacurium was adjusted to maintain T1/T0 at approximately 5% for at least 60 min. Duration from application of the initial bolus until recovery to T1/T0 = 5% (dur 5), the mean mivacurium infusion rate (IR), infusion time, the early recovery time from cessation of infusion to T1/T0 = 25% (rec 25) and the final recovery time from T1/T0 = 25% to T4/T1 = 75% (final rec) was measured. Statistical analysis of data was performed using t-tests. (alpha = 0.05). Predictability of the recovery times (rec 25 and final rec) was tested by multiple linear least-squares regressions. Dependent variables were PChE, dur 5, IR, infusion time, and rec 25, respectively. To test for predictability of neuromuscular blockade by mivacurium with respect to severe systemic diseases, the ASA risk score was defined to be the second independent variable at each regression, the respective interaction was defined to be the third independent variable (variable 1 x group). Variables entered multiple regression analysis in a forward stepwise manner (F > 4.0). RESULTS: PChE was significantly lower in patients with severe systemic diseases (3.7 +/- 1.2 kU/l vs. 4.5 +/- 0.9 kU/l), dur 5 significantly prolonged (17.3 +/- 7.3 min vs. 11.0 +/- 3.0 min), IR significantly lower (4.6 +/- 2.6 micrograms/kg/min vs. 6.5 +/- 2.8 micrograms/kg/min), and rec 25 (8.7 +/- 4.0 min vs. 6.0 +/- 1.7 min) as well as final rec (23.0 +/- 16.3 min vs. 13.0 +/- 3.7 min) significantly prolonged compared to patients without severe systemic diseases. Both recovery intervals correlated significantly with PChE, dur 5, or IR, but not with the ASA risk score. Multiple regression analysis revealed a close correlation between rec 25 and final rec very closely (R2 = 0.875). Prolonged mivacurium infusion time and additionally high ASA risk score were correlated with a prolonged neuromuscular recovery (R2 = 0.130). DISCUSSION: Prolonged neuromuscular recovery could be predicted from a reduced PChE, a prolonged duration of action of the initial mivacurium bolus and a decreased mivacurium-infusion rate required to maintain a 95% neuromuscular blockade. Measurement of plasma cholinesterase and monitoring of mivacurium induced neuromuscular blockade can avoid resting neuromuscular blockade postoperatively despite of prolonged neuromuscular recovery.

Systemic iodine absorption during endoscopic application of radiographic contrast agents for endoscopic retrograde cholangiopancreaticography.

Hyperthyroidism induced by contrast agents in a major problem in patients with pre-existing thyroid disease, particularly in patients with functional thyroid autonomy. The present study was undertaken to evaluate whether contrast media applied during endoscopic retrograde cholangiopancreaticography (ERCP) may result in a significant increase of serum iodine levels and thus may be associated with the risk of iodine-induced hyperthyroidism. The courses of serum concentrations of total iodine and free iodide, as well as of urinary iodine excretion, were measured in 15 patients before and up to 21 days after ERCP. During ERCP, the non-ionic contrast medium iopamidol was instilled in amounts resulting in a total iodine load of 57.4 +/- 22.8 mmol (7.3 +/- 2.9 g). In all patients, ERCP resulted in a highly significant increase in serum levels of total iodine from 0.8 +/- 0.5 to 85.2 +/- 116.9 mumol/l 4 h after application of the contrast agent. In parallel, serum iodide levels were raised from 0.06 +/- 0.04 to 5.42 +/- 6.09 mumol/l and urinary iodine excretion from 71.1 +/- 35.7 mumol/mol creatinine to 621,620.9 +/- 636,492.2 mumol/mol creatinine. Peak concentrations of serum iodine are well related to the total amount of iodine applied (p < 0.05). During follow-up, iodine levels returned to pre-exposure levels within 2-3 weeks. Levels of thyrotropin, free thyroxine, and free triiodothyronine remained unchanged during the follow-up period. In conclusion, endoscopic application of iodinated contrast agents during ERCP leads to significant increases of serum levels of total iodine and free iodide and of urinary iodine excretion.(ABSTRACT TRUNCATED AT 250 WORDS)