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Biomedical subjects

H Brugger

Publications and source records attributed to H Brugger.

At least 19 recordsLinked to original sources

[Avalanche emergencies. Review of the current situation].

In North America and Europe around 140 persons die every year due to avalanches, approximately 35 in North America, 100 in the European Alps, and 5 in other parts of Europe. Most of the victims are skiers and snowboarders. This article outlines the specific pathophysiology of avalanche burials, such as hypoxia, hypercapnia, and hypothermia and also other factors which influence survival. Strategies to minimize the mortality due to avalanches and the on-site treatment of buried persons are discussed. Finally, possibilities to reduce the number of avalanche deaths are pointed out.

Avalanches↗

Field management of avalanche victims.

The median annual mortality from snow avalanches registered in Europe and North America 1981-1998 was 146 (range 82-226); trend stable in Alpine countries (r=-0.29; P=0.24), increasing in North America (r=0.68; P=0.002). Swiss data over the same period document 1886 avalanche victims, with an overall mortality rate of 52.4% in completely-buried, versus 4.2% in partially-, or non-buried, persons. Survival probability in completely-buried victims in open areas (n=638) plummets from 91% 18 min after burial to 34% at 35 min, then remains fairly constant until a second drop after 90 min. Likewise, survival probability for completely-buried victims in buildings or on roads (n=97) decreases rapidly following burial initially, but as from 35 min it is significantly higher than that for victims in open areas, with a maximum difference in respective survival probability (31% versus 7%) from 130 to 190 min (P<0.001). Standardised guidelines are introduced for the field management of avalanche victims. Strategy by rescuers confronted with the triad hypoxia, hypercapnia and hypothermia is primarily governed by the length of snow burial and victim's core temperature, in the absence of obviously fatal injuries. With a burial time < or =35 min survival depends on preventing asphyxia by rapid extrication and immediate airway management; cardiopulmonary resuscitation for unconscious victims without spontaneous respiration. With a burial time >35 min combating hypothermia becomes of paramount importance. Thus, gentle extrication, ECG and core temperature monitoring and body insulation are mandatory; unresponsive victims should be intubated and pulseless victims with core temperature <32 degrees C (89.6 degrees F) (prerequisites being an air pocket and free airways) transported with continuous cardiopulmonary resuscitation to a specialist hospital for extracorporeal re-warming.

Cardiopulmonary Resuscitation↗

Distinct thyroid hormone-dependent expression of TrKB and p75NGFR in nonneuronal cells during the critical TH-dependent period of the cochlea.

Analyzing the thyroid hormone (TH)-dependent period of the inner ear, we observed that the presence of triiodothyronine (T3) between postnatal day 3 (P3) and P12 is sufficient for functional maturation of the auditory system. Within this short time period, an unusual transient TH-dependent expression of nonneuronal neurotrophin receptors (NT-R) trkB and p75(NGFR) was observed in correlation with neuronal and morphogenetic processes. The availability of thyroid hormone was revealed to be invariably correlated with (a) a transient expression of full-length trkB in TRalpha1-, TRalpha2- and TRbeta1-expressing hair cells concomitant to the segregation of afferent fibers and the synaptogenesis of efferent fibers; and (b) a transient expression of p75(NGFR) in TRalpha1- and TRbeta1-expressing great epithelia ridge cells in direct spatiotemporal correlation with the appearance of apoptotic cells and morphogenetic maturation of the organ. For the first time, these data suggest a TH dependency of the expression of neurotrophin receptors in nonneuronal cells. A potential role of these peculiar neurotrophin receptor expression for the conversion of the biological function of TH on innervation patterning and morphogenesis during the critical TH-dependent period of the inner ear may be considered.

Animals↗

[Avalanche emergency. New aspects of the pathophysiology and therapy of buried avalanche victims].

A series of investigations on the pathophysiology and management of persons buried in an avalanche has been undertaken over the past few years in response to increased awareness of the importance of emergency medical treatment of avalanche victims and the fact that the high mortality rate has not decreased in spite of the improvement in rescue techniques. This paper is the very first review of the problems encountered in avalanche disasters. The developments over the past 20 years, in particular, are summarized and discussed. Furthermore, current opinions and recommendations on optimal rescue procedure, as well as the prevention of such emergencies are presented. Precise assessment of the survival probability after burial under an avalanche and recognition of the prognostic importance of an air pocket, but only limited role of hypothermia, provide the basis for new concepts governing therapy and triage by the emergency doctor. Resulting guidelines have been endorsed by the Emergency Medicine Subdivision of the International Commission of the Alpine Rescue Services (ICAR) and these recommendations are intended for implementation by organised rescue teams in order to reduce secondary deaths following successful extrication of victims from the avalanche masses. However, the chance of being rescued alive depends primarily on the rapidity of extrication, i.e. how quickly the rescue teams are alerted and transported to the disaster area in the first instance, then how quickly the victims are located and extricated. In order to reduce the mortality additional preventive measures must be introduced to avoid complete burial if possible, or appreciably hasten the rescue procedure. The very steep drop ("fatal kink") in survival probability as from 15 minutes after burial underlines the absolute necessity of the mastery of efficient rescue procedure by uninjured companions. Improvement of the technical developments for the avoidance of total burial (avalanche air bag) and optimization of the electronic location (transceiver) of buried skiers by uninjured companions are essential future requirements. Nonetheless, primary prevention remains of paramount importance in governing decision making by offpiste skiers. Correct assessment of the inherent risks according to the prevailing circumstances and strict adherence to safety rules take precedence over all other considerations.

Asphyxia↗

A totally implantable drug delivery system for local therapy of the middle and inner ear.

Local therapy of middle and inner ear diseases is being used, but is restricted to cases of ear drum perforation or to repeated invasive intratympanic drug application by the physician. In accordance with the Medical Device Directive (class III), a bone-anchored, totally implantable drug delivery system (TI-DDS) has been developed. It includes a micropump for subcutaneous, patient-controlled activation, a drug reservoir and a septum port. A thin guide-wired catheter leads from the pump outlet to the point of application in the mastoid or middle ear cavities. Local inner ear therapy with suitable drugs is possible by positioning the catheter's end near the round window membrane. The system requires no battery and will offer a wide range of patient-controlled bolus applications (25 microliters per activation). We first analyzed the three-dimensional implantation geometry of the mastoid cavity. Basic micromechanical problems have been solved in order to create several prototypes. The TI-DDS has already undergone extensive in vitro testing. Recent results of pump rate precision and digital pressure force testing are promising. Local drug treatment for conditions such as lidocaine-sensitive tinnitus, secretory otitis media, Meniere's disease, localized pain and intralesional cancer is under discussion. Furthermore, local application of future biotechnological trophic factors for inner ear treatment is anticipated. The basic engineering is completed and initial animal tests are in preparation.

Animals↗

On-site triage of avalanche victims with asystole by the emergency doctor.

Asystole in avalanche victims is generally due to asphyxia and not primarily to hypothermia. Hence, on-site establishment of death by asphyxiation would avoid evacuation risks to the rescue party, as well as high costs of transport to, and treatment at, frequently distant specialist centres in cases with a hopeless prognosis. This paper presents a novel differential diagnosis scheme based on burial duration (critical time 45 min) and core temperature (critical level 32 degrees C) of the person on extrication, as well as the presence or absence of an air pocket, facilitating on-site identification of asphyxiated victims. When information regarding an air pocket is uncertain in victims buried longer than 45 min, determination of serum potassium (critical level 10 mmol/l) at the nearest hospital becomes an alternative criterion for triage. The proposed guidelines aim to clarify field decision-making for the emergency doctor with respect to discontinuation of resuscitation and limitation of transferral for cardiopulmonary bypass core rewarming to those patients with presumptive reversible hypothermia.

Air↗

[High altitude lung edema in the East Alps].

We present a case of high-altitude pulmonary edema in a trained skier who undertook a three-day tour in the eastern Alps. This clinical condition can occur in hitherto healthy, predisposed persons at a critical altitude of 2500-3000 m and has to be differentiated above all from pneumonia. Extreme physical exertion, especially at low temperatures, the intake of alcohol or hypnotics and, presumably, preceding infection of the respiratory tract favor the occurrence of high-altitude pulmonary edema. The history of having spent the night at or above the critical altitude and the spontaneous restitutio ad integrum with rapid clinical recovery and dissolution of the radiographic pulmonary infiltrates within a few days after evacuation to lower altitudes are decisive features in establishing the diagnosis. Without therapy or evacuation the mortality rate is 50%. In spite of the low incidence in the eastern Alps, as opposed to the western Alpine countries, the potentially fatal course of high-altitude pulmonary edema should make it mandatory to equip huts and refuges above 3000 m even in the eastern Alps with the first-aid medicament nifedipine and therapeutic oxygen.

Adult↗

[New perspectives of avalanche disasters. Phase classification using pathophysiologic considerations].

This study comprises an analysis of the data on 332 persons totally buried by avalanches in Switzerland between 1981 and 1989. The survival rate was calculated with the aid of a computer-assisted estimation procedure according to Turnbull. The curve pattern was interpreted according to pathophysiological considerations, on the basis of which the time course of the battle for survival was divided into 4 phases: 1) Survival phase: until 15 minutes after burial under the snow masses. The survival probability amounts to 93% and is, thus, higher than so far assumed. Almost all those buried survived this period of the time provided they were not fatally injured and received first aid. 2) Asphyxia phase: duration of burial under the avalanche from 15 to 45 minutes. The probability of survival sank dramatically during this period from 93% to about 25% (fatal kink of the survival probability curve). Those buried under the snow without an air pocket die of acute asphyxia (the point of no return) and the mortality rate reaches its maximum in this phase. 3) Latent phase: the period as from 45 minutes following the avalanche until the time of rescue. This phase is survived only in the presence of an air pocket. With sufficient oxygen reserves and freedom of thoracic movement a "phase of relative safety" occurs, whereby the survival probability diminishes further only slowly. The first deaths due to hypothermia arise after 90 minutes. 4) Rescue phase: from the time of extrication from the snow until arrival in hospital. There is an increased risk of a fatal outcome during the rescue procedure and immediately afterwards through augmented hypothermia.(ABSTRACT TRUNCATED AT 250 WORDS)

Asphyxia↗