Changes in cardiac index and blood pressure on positioning children prone for scoliosis surgery.

In this prospective observational study we investigated the changes in cardiac index and mean arterial pressure in children when positioned prone for scoliosis correction surgery. Thirty children (ASA 1-2, aged 13-18 years) undergoing primary, idiopathic scoliosis repair were recruited. The cardiac index and mean arterial blood pressure (median (IQR [range])) were 2.7 (2.3-3.1 [1.4-3.7]) l.min(-1).m(-2) and 73 (66-80 [54-91]) mmHg, respectively, at baseline; 2.9 (2.5-3.2 [1.7-4.4]) l.min(-1).m(-2) and 73 (63-81 [51-96]) mmHg following a 5-ml.kg(-1) fluid bolus; and 2.5 (2.2-2.7 [1.4-4.8]) l.min(-1).m(-2) and 69 (62-73 [46-85]) mmHg immediately after turning prone. Turning prone resulted in a median reduction in cardiac index of 0.5 l.min(-1).m(-2) (95% CI 0.3-0.7 l.min(-1).m(-2), p=0.001), or 18.5%, with a large degree of inter-subject variability (+10.3% to -40.9%). The changes in mean arterial blood pressure were not significant. Strategies to predict, prevent and treat decreases in cardiac index need to be developed.

[Reduced neuromuscular blocking potency of atracurium in patients with purulent intrathoracic diseases]. / Verminderte Wirksamkeit von Atracurium bei Patienten mit intrathorakalem Eiterherd.

OBJECTIVE: Based on personal observations the neuromuscular blocking potency of atracurium was supposed to be diminished in purulent intrathoracic diseases. This hypothesis was tested in a prospective clinical trial. METHODS: 52 adult patients undergoing general anaesthesia (methohexitone, sufentanil, flunitrazepam, N2O, enflurane) for elective thoracic surgery were investigated. After the intubation dose of 0.6 mg/kg atracurium was applied continuously to maintain a 90% suppression of the evoked compound electromyogram. According to the intraoperatively established diagnosis patients were allocated to three categories: 1) non-malignant tumor as the control group (n = 15), 2) lung cancer (n = 22), 3) purulent intrathoracic process without tumor (n = 15). The groups were compared regarding onset time, DUR 10% and maintenance dose of atracurium. RESULTS: Patients with lung cancer did not differ significantly from the controls regarding efficiency of atracurium. In contrast, patients with a purulent intrathoracic process showed a significantly longer onset time (6.3 +/- 2.5 vs. 2.9 +/- 0.8 min, p < 0.001), and a significantly shorter DUR 10% (23 +/- 6 vs. 36 +/- 10 min, p < 0.001) compared to the control group. Mean infusion rate of atracurium to maintain a 90% suppression of the evoked compound electromyogram was significantly higher in patients with a purulent process compared to the controls (10.5 +/- 3.2 vs. 6.0 +/- 1.2 micrograms/kg.min, p < 0.001). CONCLUSION: Our results support the hypothesis that patients with a purulent intrathoracic disease show a clear reduction in neuromuscular blocking potency of atracurium.

Computer aided analysis of heart rate variability in brain death.

Forty neurosurgical, artificially ventilated patients were examined. Twenty of them had been diagnosed as brain dead, while twenty non-brain-dead patients served as a control group. From a surface ECG taken over a period of five minutes the mean heart rate and various indices of heart rate variability (HRV) were determined with the help of a special computer program (ProSciCard, Medisyt, Germany). The heart rate of the brain dead was significantly higher than that of the control patients. By contrast, all parameters of HRV were drastically reduced in the brain dead individuals compared to the controls. The results show that a significant change in the course of heart rate occurs after manifestation of brain death. This would appear to be the result of the elimination of all vegetative impulses derived from the brainstem. Computer-aided, the changes can be quantified in a simple way. The method could therefore be useful in brain death diagnosis.

[Waiting for the crisis]. / Warten auf die Krisis.

AIM OF THE STUDY: Experience in daily routine reveals that most of ICU patients usually go through "crisis" within 14 days of admission. Only few patients need remarkable more time to get to this point and it seems there is hardly anything to be done therapeutically to change the course of it. We therefore examined a large group of ICU patients in order to find reasons for this course or to spot them as an "entity of their own". METHODS: 1,861 ICU patients all being on IPPV for more than three days were included in the study. Every day 18 variables were taken down in a standardised way until the day IPPV was finished. We extracted 170 patients who were artificially ventilated for more than 40 days. For these patients we established mean values for each of the 18 variables during the first and the last 40 days of ventilation. In both groups we compared survivors to non-survivors. RESULTS: Mortality was almost the same in both groups (IPPV < 40 days vs. IPPV > 40 days). Survivors and non-survivors showed remarkable differences regarding extrapulmonary factors-in terms of total fluid amount and transfusion, state of abdomen, brain, liver and kidney function and circulation problems. Pulmonary factors revealed major differences only towards the end of the observation period. CONCLUSIONS: There seems to be an "entity of ist own", a small population of patients who arrive at the crucial turning point later. Pulmonary complications (pneumonia, ARDS) is not the reason but the expression of cause for prolonged ventilation. The key to the extrapulmonary origin of the crisis remains unknown, the only thing we can do is alleviate its manifestations.

Limited applicability of the DATEX Reloxograph in diabetics with peripheral polyneuropathy.

The aim of the study was to investigate whether peripheral nerve dysfunction can influence the applicability of the DATEX Relaxograph in diabetics. Sixty two patients (43 diabetics, 19 non-diabetics) undergoing ophthalmosurgical procedures under general anesthesia were tested. The distal motor latency (DML) of the ulnar nerve served as a graduation tool for peripheral nerve dysfunction. The patients were divided in three groups: non-diabetics (group 1), diabetics with DML < 3.8 msec (group 2), diabetics with DML > 3.8 msec (group 3). Relaxometry was performed by stimulating the right ulnar nerve near the wrist, and the evoked response (EMG) was obtained from the hypothenar muscle. Calibration of the device (i.e. supramaximal stimulation within the given current range of a maximum of 70 mA) was carried out successfully in most patients of group 1 and 2 (94.7% and 85.7% respectively). In contrast to that calibration could be carried out in only 40.9% of the patients of group 3 (P < 0.01 vs. group 1 and 2). Consequently in a high percentage (59.1%) of the patients of group 3 relaxometry had to be performed in an uncalibrated manner. The results substantiate the hypothesis that peripheral nerve dysfunction can restrict the applicability of the Relaxograph in diabetics.