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Biomedical subjects

N G Bircher

Publications and source records attributed to N G Bircher.

31 records · Page 2Linked to original sources
PubMed1994

Quality of bystander cardiopulmonary resuscitation influences outcome after prehospital cardiac arrest.

To evaluate the influence of quality of bystander cardiopulmonary resuscitation (CPR) on outcome in prehospital cardiac arrest we consecutively included patients with prehospital cardiac arrest treated by paramedics in a community run ambulance system in Oslo, Norway from 1985 to 1989. Good CPR was defined as palpable carotid or femoral pulse and intermittent chest expansion with inflation attempts. Outcome measure was hospital discharge rate. One hundred and forty-nine of 334 patients (45%) received bystander CPR. The discharge rate after good BCPR (23%) was higher than after no good BCPR (1%, P < 0.0005) or after no BCPR (6%, P < 0.0005). There was no difference between no good and no BCPR (P = 0.1114). There were no differences in paramedic response interval between the groups, but the mean interval from start of unconsciousness to initiation of CPR (arrest-CPR interval) was significantly shorter in the group receiving good bystander CPR (2.5 min, 95% confidence interval (CI): 1.7-3.3 min) than no good CPR (6.6 min, CI: 5.2-8.0 min) or no bystander CPR (7.8 min, CI: 7.2-8.4 min). Bystanders started CPR more frequently in public than in the patient's home (58 vs. 34%, P < 0.0005). Good bystander CPR was associated with a shorter arrest-CPR interval and improved hospital discharge rate as compared to no good BCPR or no BCPR.

Adolescent↗
PubMed1993

ATP-MgCl2 pre-treatment in an animal model of asphyxial arrest.

ATP-MgCl2 treatment has been found to be a promising intervention in many models of hypoxic/ischemic injury. In this study, the effect of pre-treatment with ATP-MgCl2 on the hemodynamic response to asphyxia in the rat was examined. Rats were anesthetized with halothane and N2O2. A tracheostomy and femoral artery and vein cutdowns were performed. Rats were infused intravenously with either ATP-MgCl2 (approximately 50 mumol/kg) or normal saline (control group) over 15 min. Animals were then asphyxiated for 8 min by occlusion of the ventilator tubing. Following the asphyxia, 1 min of cardiopulmonary resuscitation (CPR) was attempted. Heart rate and blood pressure were monitored continuously throughout the experiment. A total of 41 animals (21 ATP-MgCl2, 20 control) were studied. Analysis of variance (ANOVA) was used to test for differences between groups. The ATP-MgCl2 group had a lower heart rate (HR) and mean arterial pressure (MAP) during the infusion. During asphyxia the ATP-MgCl2 group had a lower MAP but higher HR when compared to the control group. No significant differences were observed in the rates of successful resuscitation between ATP-MgCl2-treated rats (10 of 21, 48%) and controls (12 of 20, 60%). Possible reasons for the apparent lack of benefit of ATP-MgCl2 therapy are discussed.

Adenosine Triphosphate↗
PubMed1993

Pathophysiologic and therapeutic implications of acid-base changes during CPR.

Acid-base changes occurring during cardiac arrest and subsequent CPR are related to a complex low-perfusion state characterized clinically by venous and tissue hypercarbic and metabolic (lactic) acidosis. This low-flow state is a dynamic process dependent on the time intervals between onset of arrest, initiation of CPR, and restoration of adequate spontaneous circulation. Increased release of CO2 from ischemic tissues and reduced CO2 transport from the tissues to the lungs result in profound tissue acidosis. However, recent experimental data suggest that even very low pH is compatible with neurologically intact survival. Thus, the clinical use of buffer agents, and especially of sodium bicarbonate, is currently controversial. Because results of controlled clinical studies are not available, a careful review of well-performed experimental studies is necessary. So far, the use of either CO2-generating or CO2-consuming buffers has not been proved conclusively to increase neurologically intact long-term survival after CPR. More importantly, adequate ventilation and effective chest compressions must be quickly established after cardiac arrest. This will counterbalance the hypercarbic and metabolic acidemia of cardiac arrest by creating concurrent hypocarbic arterial alkalemia during at least the early phase of CPR. Thus, the treatment of the complex acid-base changes associated with CPR is based primarily on the classical maneuvers of A and B (airway and breathing = adequate oxygenation and ventilation), C (chest compressions), and D (early defibrillation for rapid restoration of spontaneous circulation). In cases of prolonged cardiac arrest or preexisting metabolic acidemia, buffer therapy may be indicated.

Acid-Base Imbalance↗
PubMed1993

Impairment of anesthesia task performance by laser protection goggles.

This study was designed to determine whether the wearing of colored goggles, commonly used during laser surgery, increased the time needed to perform simple tasks or the likelihood of medication errors. The Stromberg Dexterity Test and the Medication Sorting Task (MST), a test of our own design, were used to measure the speed and accuracy of identifying medications. Thirty anesthesia care providers performed the tests twice, once with colored goggles and once without. Ambient light during the test was controlled to approximate that in the operating room during laser surgery. Times required to complete the tests improved with repetition of the test. When colored goggles were worn, more time was needed to complete the tests. More errors, especially serious errors in medication sorting, occurred when goggles were worn than when they were not. The wearing of colored goggles in combination with low levels of illumination and stress due to time constraints, may increase the potential for medication errors.

Anesthesiology↗
PubMed1990

"Re-evaluation" of CPR.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Brain resuscitation.

Optimal neurological outcome after cardiac arrest requires careful attention to the details of both intracranial and extracranial homeostasis. A high index of suspicion regarding the potential causes and complications of cardiac arrest facilitates discovery and treatment of problems before they adversely impact upon neurological outcome. The future is bright for resuscitation research since our fundamental understanding of cerebral ischemia and its consequences has dramatically improved. This knowledge can hopefully be transferred to clinical useful modes of therapy.

Brain↗
PubMed1989

Neurologic management following cardiac arrest.

Optimal neurologic outcome after cardiac arrest requires careful attention to the details of both intracranial and extracranial homeostasis. A high index of suspicion regarding the potential causes and complications of cardiac arrest facilitates discovery and treatment of problems before they adversely affect neurologic outcome. The future is bright for resuscitation research: Our fundamental understanding of cerebral ischemia and its consequences has dramatically improved, and this knowledge can hopefully be transferred to clinical useful modes of therapy. However, the transition from a promising, therapeutically effective intervention in animals to the demonstration that treatment is effective following cardiac arrest in humans is an important and difficult step. The patient population is heterogeneous before the insult, the duration and severity of the insult are variable, and the effectiveness of cardiopulmonary resuscitation varies among institutions. Therefore, the only means of demonstrating clinical efficacy is the performance of a large clinical trial. The Resuscitation Research Center at the University of Pittsburgh has developed and coordinated a multicenter, multinational team of investigators who have completed one definitive trial of postarrest barbiturate therapy and are currently completing a similar trial using a calcium entry blocker. Despite the formidable obstacles posed by such comprehensive efforts, they provide the mechanism for determining whether the cost of a new treatment modality is justified by the likelihood of improved mortality or morbidity.

Brain Ischemia↗
PubMed1985

Ischemic brain protection.

Despite advances in the understanding of the pathophysiology of cerebral ischemia, no single brain resuscitation therapy has yet been shown to be clinically superior to brain-oriented intensive care. Basic concepts in cardiopulmonary-cerebral resuscitation (CPCR) are discussed, as are two specific phases of CPCR, cerebral preservation and cerebral resuscitation. Cerebral preservation is initiated during cardiac arrest (ie, prior to restoration of spontaneous circulation [ROSC]) and includes use of artificial perfusion techniques and drugs to produce cerebral perfusion during this phase. Cerebral resuscitation is brain-oriented therapy initiated after ROSC. Pharmacologic agents currently under study for cerebral resuscitation include the barbiturates, calcium antagonists, and iron chelators. With respect to defining efficacy of the pharmacologic agents, the concept of therapeutic window is important. Although no agent has been proven clinically, several appear to be promising.

Animals↗