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Biomedical subjects

T Prien

Publications and source records attributed to T Prien.

At least 19 recordsLinked to original sources
PubMed1992

Mechanical alteration of blood flow in smoked and unsmoked lung areas after inhalation injury.

The degree of pulmonary perfusion may have an important role in the pathogenesis of inhalation injury. We studied this in sheep that had only one lung exposed to smoke. The right lung and upper airway of 12 chronically instrumented sheep were insufflated with cotton smoke. In six animals, the left pulmonary artery was occluded between 4 and 10 h after smoke insufflation. All animals were studied for 24 h and then killed, and lung tissue was harvested. The smoked as well as the air-insufflated lung of all animals showed an increase in wet-to-dry weight ratio and tissue conjugated dienes (products of lipid peroxidation). Neither the intermittent blood flow increase to the smoked lung nor the simultaneous blood flow reduction with a concomitant polymorphonuclear neutrophil entrapment in the air-insufflated lung significantly affected the histopathological outcome of the respective lung. We conclude that tissue damage after inhalation injury cannot be diminished by increasing the flow to smoked areas. Ischemia-reperfusion injury does not have a major role in the lung damage seen with inhalation injury.

Animals↗
PubMed1991

[Pulse oximetry monitoring of postanesthetic transportation of ophthalmic surgery patients: risk of hypoxemia despite pre-oxygenation].

40 adult patients, ASA class I-III, were studied with regard to their arterial oxygen saturation during transportation from the operating room to the recovery room, following ophthalmic surgery under general anaesthesia. Before transportation the patients were breathing oxygen spontaneously for 6 min.; during transportation they were breathing air. The time for the transport from the operating room to the recovery room was between two and eight minutes. Hypoxaemia (SaO2 85-90%) was observed in 18 cases, severe hypoxaemia (SaO2 less than or equal to 85%) in 5 cases.

Aged↗
PubMed1990

[Intravenous regional anesthesia of the arm and foot using 0.5, 0.75 and 1.0 percent prilocaine].

Quality of anaesthesia and risk of intoxication are competing principles in IVRA. To evaluate the optimal prilocaine concentration with injection of 40 ml, 300 patients were randomly allocated to receive either a 0.5 (PRI 0.5), 0.75 (PRI 0.5) or a 1.0 (PRI 1.0) per cent solution. Using PRI 0.5, fifteen patients required supplementary fentanyl, with PRI 0.75 one, and with PRI 1.0 two (p less than or equal to 0.05). General anaesthesia proved necessary in three patients of the PRI 0.5 and 0.75 groups, respectively, and in one patient of the PRI 1.0 group (NS). With PRI 1.0 seven patients had subjective signs of intoxication upon tourniquet release, with PRI 0.75 none, and with PRI 0.5 one (p less than or equal to 0.05). Objective symptoms of local anaesthetic toxicity were not observed. The incidence of tourniquet-related pain was 25-30% in all three groups and not related to the prilocaine concentration. In conclusion, with 40 ml injection volume the 0.75% solution of prilocaine offers the optimal relation between incidence of anaesthesia and risk of intoxication.

Adolescent↗
PubMed1990

[Inhalation anesthesia with halogenated hydrocarbons: value of isoflurane].

The halogenated hydrocarbons halothane, enflurane and isoflurane are used extensively. Like every other anaesthetic, these inhaled agents are not devoid of side effects, most of which are undesirable. This review summarises the similarities and differences between the actions of these vapours. Although isoflurane appears to be more advantageous than enflurane and halothane in certain patients, isoflurane is no panacea and the question of which agent to choose still has to be answered for every patient. A note of caution is warranted against the further use of halothane in adults, as halothane offers no advantages when compared to enflurane and isoflurane but carries a higher risk of hepatotoxicity. However, in children halothane remains the halogenated agent of first choice, when anaesthesia is induced via face mask.

Anesthesia, General↗
PubMed1989

[Respiratory and hemodynamic sequelae of unilateral inhalation injury of the lung].

Respiratory failure after smoke inhalation injury is usually preceded by a 12-48 h interval with only minor clinical symptoms. Since pulmonary lesions show a patchy distribution, it has been postulated that vasoconstriction in more severely damaged areas induces a shift of pulmonary blood flow to less severely damaged areas, minimizing venous admixture. This hypothesis was tested in a sheep model in which only one lung was exposed to smoke. Six chronically instrumented (arterial, central venous, pulmonary artery thermodilution, and left atrial catheters; ultrasonic transit time flow probe around the left pulmonary artery) range ewes were intubated with a modified Carlens tube under halothane anesthesia. Smoke from smoldering cotton was insufflated into the left lung until a carboxyhemoglobin level of 50% was achieved. After the smoking procedure, the animals were awakened, extubated, and studied for 24 h. During this time, the pulmonary vascular resistance of the left lungs increased fourfold while the pulmonary vascular resistance of both lungs only doubled. Left pulmonary artery blood flow decreased progressively to 37% of control at 24 h, while cardiac output decreased by only 25%. PaO2 decreased from 107 +/- 12 to 77 +/- 15 mmHg at 24 h. Mean pulmonary arterial pressure rose from 18 to 23 mmHg. Heart rate, mean arterial pressure, left atrial pressure, and PaCO2 showed no statistically significant changes. The results indicate that the response of the pulmonary vasculature to smoke inhalation injury is a two-phase phenomenon. In the first phase, vasoconstriction occurs to counterbalance injury-induced ventilation-perfusion mismatching.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Magnetic resonance tomography: a patient-connected system for artificial respiration and monitoring].

Physical phenomena that occur during magnetic resonance imaging (MRI) and the position of the patient inside the scanning tube necessitate adaptations of anesthetic techniques and devices. An anesthesia unit is presented that operates in close proximity to the patient without interfering with the imaging process. This unit enables the anesthesiologist to be close to the patient and his equipment, and minimizes the length of necessary tubing between patient and anesthesia apparatus. The unit consists of commonly used, commercially available devices with only minor modifications.

Anesthesia↗
PubMed1988

Early effects of inhalation injury on lung mechanics and pulmonary perfusion.

We investigated the early effects of a rather large amount of cotton-smoke on lung mechanics and pulmonary perfusion. Under halothane anesthesia 18 ewes were intubated with a double-lumen tube. In 6 sheep the left lung was exposed to smoke, in another 6 the right lung. A sham group of 6 sheep was insufflated with air instead of smoke. Prior to and 30-45 min following the smoking- (sham-) procedure the following parameters were determined for the smoke- (sham-) exposed and the contralateral lung: static compliance, inspiratory airway resistance, and physiologic dead space ratio. In addition MAP, MPAP, WP, and CO were recorded. The data indicate that inhalation of large amounts of smoke has no major direct effects on pulmonary mechanics and perfusion in the early post-injury period. Only an increase in airway resistance of the smoke exposed lungs was found, which must be attributed to a local reflex mechanism.

Animals↗
PubMed1988

Inhalation injury in burned patients: effects and treatment.

Pulmonary pathology in major thermal injury is found in 30-80 per cent of burn fatalities. The incidence and mortality from inhalation injury increases both with age and increasing burn size. Toxic smoke inhalation injury, characterized by increased lung microvascular permeability, is attenuated by increasing cardiac output to normal levels, indicating that fluid restriction after inhalation injury may lead to excessive lung fluid formation and hypoxia. Fluid administration of approximately 2 ml/kg/% area burned above the calculated resuscitation volume is required following an inhalation injury to provide adequate support for the systemic circulation and maintain cardiac output at normal levels. This additional volume does not contribute to the development of pulmonary oedema, but may decrease its formation by increasing shear forces thus reducing polymorphonuclear leucocyte deposition in the pulmonary microcirculation. Nasotracheal intubation is preferred when airway integrity is compromised by inhalation injury. The advantages are non-operative placement, ease of discontinuation, minimal bacterial contamination and leaving neck burns undisturbed. The administration of the appropriate antibiotics for documented infection is recommended, while steroids have been shown to be of no benefit.

Adolescent↗
PubMed1988

The pathophysiology of inhalation injury--a review.

The inhalation of smoke results in a series of pathophysiological events involving the respiratory and circulatory systems. Upper airway injury is mainly the result of heat damage. The lesions of the tracheobronchial and parenchymal areas are more related to the chemicals present in the smoke. The initial damage of the tracheobronchial mucosa results in chemotaxis of leucocytes into the airway tissues, with release of inflammatory mediators and formation of exudative materials. Bronchial oedema, bronchoconstriction, and bronchial obstruction by cast materials develop. The pulmonary microvasculature shows a permeability type of lesion, which is the result of mediator release from entrapped polymorphonuclear cells. This parenchymal lesion may relate to the tracheobronchial damage and be the result of a reperfusion injury. The systemic changes which have been identified relate to an increase in microvascular permeability and a reduction of myocardial contractility secondary to the inhalation of the toxic products of smoke. These latter findings may help to explain the difficulty encountered in resuscitating some of the burn victims who have concomitant inhalation injury.

Animals↗
PubMed1988

Toxic smoke compounds and inhalation injury--a review.

Although the role of inhalation injury in contributing to the mortality of burn patients has received increasing attention, the available information on the toxic and injurious effects of smoke generated from uncontrolled fires is scarce. This is because each fire generates its own variety of smoke, depending on the nature of the combusting materials and the burning conditions. This review summarizes the actions of the primary smoke components, heat, particulate materials, asphyxiants (carbon monoxide and hydrogen cyanide), and pulmonary irritants, without covering the whole field of smoke toxicity. In addition, emergency measures to counteract carbon monoxide and hydrogen cyanide poisoning are discussed.

Carbon↗
PubMed1988

[The Doppler palm test].

In 384 hands the patency of the arterial arch was investigated by means of both the Allen test and the Doppler palmar arch test as developed by the authors. While the Allen test is purely subjective and gives a high proportion of false results especially in shocked patients, the Doppler palmar arch test is based on two objective criteria: 1. Demonstration of reversed flow in the distal section of the radial artery on proximal compression. 2. Demonstration of pulsatile flow in the radial thumb artery even on compression of the radial artery. The Doppler palmar arch test eliminates all negative aspects of the Allen test and is therefore definitely more reliable than the latter. It is easy to perform for investigators having little experience with Doppler sonography. The time consumed is not greater than with the Allen test.

Arteries↗