Walter Rabl

The contribution of anulus fibers to torque resistance.

Study Design Anulus fibers of the intervertebral disc oriented in one direction were dissected, and oppositely directed fibers were left intact as a result of a newly developed dissection method. Motion segments were dissected by this way, and motion segments after bilateral facetectomy were loaded in torsion and compared with each other. Objectives To assess the contribution of facets and anulus fibers to torque resistance. Summary of Background Data Mathematical models predict that torsional stress is transmitted only to those collagene fibers of the anulus that are angled in the direction of the applied torque. Torsion and forward bending or torsion and compression are likely to cause anulus damage. No experimental study that we are aware of has confirmed that anulus fibers are the main structure to resist against torque. Methods Pure axial rotation moments were applied on 12 lumbar motion segments. The six components of motion were recorded. Six motion segments were investigated intact after dissection of anulus fibers directed in one direction and after additional bilateral facetectomy. In six motion segments, bilateral facetectomy was performed before anulus dissection. Results With the application of an axial rotation moment of 8.5 Nm to the left, axial rotation increased 2° after dissection of disc fibers in one direction, and 1.2° after bilateral facetectomy (P = 0.002). In the opposite direction, there were no differences. After both injuries, axial rotation was 7.6° to the left (direction of fiber dissection) and ‐3.3° to the right (P = 0.0005). Conclusion In lumbar motion segments without degeneration, anulus fibers restrict axial rotation more than the facets.

Chest injuries after active compression–decompression cardiopulmonary resuscitation (ACD-CPR) in cadavers

In a prospective study of 38 cadavers of patients older than 18 without previous chest injury or cardiopulmonary resuscitation (CPR), active compression-decompression (ACD) resuscitation manoeuvres were performed to determine possible factors influencing sternal and/or rib fractures. ACD was performed for 60 s, with compression and decompression forces being continuously recorded. A stepwise logistic regression analysis was applied. Factors analyzed were age, gender, use of a compression cushion beneath the piston of the ACD device (Ambu CardioPump), and maximal compression and decompression forces. After ACD, the cadavers were autopsied and thoracic injuries were assessed. There was a significant correlation between sternal fractures and gender (P = 0.008), and between rib fractures and age (P = 0.008). Women were found to have a higher risk for sternal fractures, whereas older patients had a higher risk for rib fractures. Maximal compression force was another factor in sternal and/or rib fracture (P = 0.048). Even though a significantly higher incidence of sternal fractures was observed when the compression cushion was used (P = 0.045), inclusion of this variable in the regression analysis only marginally improved the prediction for correct classification of sternal fractures. In conclusion, when well controlled ACD-CPR is performed in cadavers, age is the most important factor determining the incidence of rib fracture. Sternal fractures were more common in female cadavers.

SERIOUS COMPLICATIONS FROM ACTIVE COMPRESSION-DECOMPRESSION CARDIOPULMONARY RESUSCITATION

Complications arising from techniques of cardiopulmonary resuscitation (CPR) were reviewed by analysing the autopsy protocols of 25 patients who died after standard (Std) CPR and 31 who died after active compression-decompression (ACD) CPR, 15 of them preceded by Std CPR.The results can be summarised as follows:After Std CPR (n = 25) rib fractures were detected in 28%, sternal fractures in 16%, and no injuries in 68%.After ACD-CPR (n = 16) rib fractures occurred in 68%, sternal fractures in 68% and no injuries in 25%.After ACD-CPR following Std CPR(n = 15) rib fractures were detected in 93%, sternal fractures in 93%, and no patients were without thoracic fracture. In two patients severe cardiac injuries occurred clearly attributable to CPR.In conclusion cardiopulmonary resuscitation by the ACD-technique caused rib and sternal fractures more often than Std CPR and has a higher risk for iatrogenic cardiac and possible fatal injury.

Increased frequency of thorax injuries with ACD-CPR ☆

A prospective, randomised out-of-hospital study in a two-tiered system with active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) versus standard (STD) CPR in patients following non-traumatic cardiac arrest was planned to test the hypothesis that ACD-CPR by the first tier may increase the occurrence of ventricular fibrillation as compared with STD-CPR. Furthermore, in a later phase of the study, sternal and rib fractures induced by both CPR methods were determined by extensive autopsy. After enrolling 90 patients the study was terminated because of a high frequency of chest injuries found at autopsy. Forty-two patients received STD-CPR from the first tier and ACD-CPR from the second tier. Thirty-three patients received ACD-CPR only by the first and the second tier, while 15 patients received STD-CPR only from the first and second tiers. In order to obtain a sufficiently large control group for autopsy findings after STD-CPR, STD-CPR was performed in an additional 33 patients within a second period of 4 months. There was no improvement in the number of patients found in ventricular fibrillation after ACD-CPR as compared to STD-CPR performed by the first tier. In patients undergoing autopsy (n = 35) there were significantly more sternal fractures with ACD-CPR versus STD-CPR (14/15 vs. 6/20; P <0.005) and rib fractures (13/15 vs. 11/20; P < 0.05) In conclusion, ACD-CPR appears to cause more CPR-related injuries than does standard CPR, but as a result of a number of limitations on this study, this fact cannot be proven beyond doubt.

Pulmonary Aspergillus colonization in humans and its impact on management of critically ill patients

Samples of lung tissues were obtained and analysed for Aspergillus carriage in 56 patients undergoing thoracic surgical intervention and 18 people who had an unexpected death. Out of 74 samples, 46 (63%) had evidence of pulmonary fungal colonization. The surgery population had a rate of 62% of fungal growth, Aspergillus was present in 39%. The autopsy population had a rate of 61% of fungal colonization, Aspergillus was present in 41%. In these cases eradication of fungal spores residing in the lung prior to aggressive chemotherapy and prevention of further spore uptake during hospitalization is indispensable in preventing pulmonary aspergillosis.

Review of active compression-decompression cardiopulmonary resuscitation (ACD-CPR) Analysis of iatrogenic complications and their biomechanical explanation

Our review takes a critical look at the active compression-decompression technique (ACD) for cardiopulmonary resuscitation (CPR). ACD-CPR was developed following a report of successful resuscitation performed by a medical amateur using a household plunger. The efficacy of the principle of active decompression has been demonstrated by animal and human studies. Potential iatrogenic complications from the CardioPump were evaluated only when large clinical trials were already underway. Our prospective analysis of autopsy patients and systematic randomised studies in corpses prove that ACD-CPR using the CardioPump considerably increases the rate of iatrogenic complications and especially of sternum fractures. The experimental use of the CardioPump in corpses and the analysis of a variety of different parameters, especially of the rubber cushion pads mounted in the silicone cup to prevent skin abrasions, revealed a statistically significant correlation between sternum fractures and female sex (P < 0.01) and usage of the rubber cushion pad (P = 0.045). Biomechanical studies showed that the transmission of forces from the CardioPump is greatly dependent on chest shape. The lower the sternum is sunken compared with the surrounding structures, the higher the force which is transmitted via the central area of the device onto the sternum. The rubber cushion pad shortens the distance between CardioPump and sternum by 5 mm and therefore increases the sternal loading. Sex differences in the shape of the sternum and especially the thickness may account for the significant correlation between sternum fractures and female sex.

Camphor ingestion for abortion (case report)

The case of a 16-year-old girl who ingested 30 g of camphor dissolved with 250 ml wine to induce abortion is reported. The girl started vomiting 45 min after ingestion, which may have saved her life. Camphor is present in a number of over-the-counter medications, mainly for external application, and is readily available in drugstores. The substance is highly toxic and rapid in onset. The reported human lethal dose is 50 to 500 mg kg-1. Camphor ingestion may lead to abortion because camphor crosses the placenta and fetuses lack the enzymes to hydroxylate and conjugate with glucuronic acid. The girl was charged with intended abortion.

Biomechanical properties of the human tibia: fracture behavior and morphology

Standardized biomechanical dynamic load tests were performed to obtain fundamental information on the fracture behavior and morphology of the human tibia. After preparation, the specimens (n = 32) were loaded to breakage by ventral (one side alternately), dorsal, medial or lateral loading on a servo-hydraulic testing machine (Walter und Bai, Löhningen, Switzerland). Primary and secondary fracture lines and fissures were marked differently on the three surfaces of the tibia specimens. They were then videoscanned and digitized on a flatbed scanner to give two-dimensional fracture-line images. Load limits were 2475 to 12,206 Newton. The study revealed both direct fracture patterns with the fracture lines originating from the opposite site of impact, and indirect fracture patterns originating from the distal third of the specimens. Direct fractures occurred in 46% of the specimens after ventral loading, in 80% after medial or lateral loading, and in 100% after dorsal loading. Ventral, medial or lateral loading frequently produced direct wedge fractures of the Messerer type. Dorsal loading resulted in different direct patterns characterized by transverse fractures with longitudinal fissures at the impact site of the loading stamp. Direct transverse fractures also often showed a wedge-shaped pattern due to additional fissures. These were, however, identifiable only after maceration of the specimens and should receive closer attention in forensic practice.

Fatal accident caused by isoflurane abuse.

Abstract. A fatal accident after isoflurane abuse is presented in this report. A hospital employee was found dead in the operating area with a plastic bag over his head. In his locker an almost empty bottle of isoflurane was found. Autopsy revealed signs of asphyxiation and toxicological examination revealed nordazepam and isoflurane in non-toxic concentrations in the blood. Quantification of the anaesthetic was also carried out in urine, gastric contents, liver, kidney and brain samples, and in addition, oxazepam, prothipendyl and metabolites of midazolam and prothipendyl were found in the urine. Although the drug problems of the deceased were known before, no efforts had been made to restrict access to these drugs.

Iatrogenic ruptures of the stomach after balloon tamponade. Two case reports: viscoelastic model.

Two cases of gastric rupture as a rare complication of balloon tamponade for esophageal varices are presented. In both cases, the rupture was caused by instillation of irrigation fluid without previous aspiration of stomach contents. In an experimental study, the stomachs of 11 corpses were filled with water to determine rupture pressure and volume. The mean rupture Pressure was 73 ± 13 mm Hg (9.7 ± 1.7 kPa) and the mean rupture volume was 2,670 ± 410 ml. A viscoelastic model was used for the representation of the relations between pressure and volume as well as pressure and time. Measured values are significant particularly for the explanation and medicolegal evaluation of iatrogenic ruptures of the stomach that occur during gastric lavage, positive pressure respiration, incorrect intubation, or forced mask respiration during resuscitation.