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Biomedical subjects

L A Cobb

Publications and source records attributed to L A Cobb.

At least 73 records · Page 4Linked to original sources
PubMed1984

On sudden death.

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Death, Sudden↗
PubMed1984

Considerations in the long-term management of survivors of cardiac arrest.

The heterogeneity of resuscitated patients at risk of recurrent cardiac arrest serves to make their management difficult and complex. It is logical that therapy should be tailored to each patient and certainly to the mechanism whereby sudden cardiac death occurred. It is important, also, to recognize that not all resuscitated victims are at high risk for recurrence and that aggressive interventions are not necessarily mandatory. In the patient with cardiac arrest related to transient myocardial ischemia, a direct approach toward relieving ischemia seems appropriate. Antiarrhythmic agents may have a role in the treatment of some patients, but to this date the efficacy of such therapy is speculative, at best. The development and testing of agents that have "antifibrillatory" properties seems a logical approach at this time. Clearly, efforts to lessen the mortality of patients who have been resuscitated from out-of-hospital cardiac arrest are important, not only for the particular patients themselves, but also in an effort to develop rational, prophylactic interventions for the large numbers of patients with coronary heart disease who are at risk for the development of sudden cardiac death.

Adrenergic beta-Antagonists↗
PubMed1984

Improved neurologic recovery and survival after early defibrillation.

Eighty-seven patients who had out-of-hospital cardiac arrests received defibrillating shocks delivered by minimally trained first responders before the arrival of paramedics in a city with short emergency response times. Their outcomes were compared with those of 370 other victims who received only basic life support by first responders until paramedics arrived. Survival was improved by early defibrillation in cases in which there was a delay in initiating cardiopulmonary resuscitation and in which paramedic response times exceeded 9 min; there was 62% survival after early defibrillation by first responders and 27% if first responders provided only basic life support (p less than .02). Neurologic recovery was also improved after early defibrillation. Eighteen of 46 resuscitated patients (39%) receiving early defibrillation were awake at 24 hr compared with 49 of 204 patients (24%) who received only basic life support while awaiting paramedics (p less than .02). Incorporating defibrillation as part of basic life support can reduce both mortality and morbidity from cardiac arrest, even in cities with established, rapidly responding emergency care systems.

Allied Health Personnel↗
PubMed1984

Health status of survivors of out-of-hospital cardiac arrest six months later.

The health status of long-term survivors of out-of-hospital cardiac arrest was studied six months after the event. Although Sickness Impact Profile scores for arrest survivors were higher (worse) than scores of enrollees in a prepaid closed panel health plan, in most cases problems of survivors were not incapacitating. Approximately three-fifths of survivors reported same or better memory function and stair climbing ability compared to that at time of arrest. Three-fifths of those who had been working continued to do so.

Activities of Daily Living↗
PubMed1984

Ventricular fibrillation causes sudden death in Southeast Asian immigrants.

Young, male, Southeast Asian immigrants living in the United States have a high incidence of unexplained, sudden, nocturnal death. We report the cases of three patients, two Laotians and one Filipino, who were resuscitated and subsequently studied extensively. Each patient was having ventricular fibrillation when first examined by paramedics outside the hospital, and episodes of fibrillation recurred in the early hospital course. Clinical evaluation found no significant coronary atherosclerosis or structural cardiac disease. One patient is asymptomatic after 2 years; the second patient died suddenly at 4 months; and the third is asymptomatic but had inducible ventricular tachycardia on electrophysiologic testing 6 months after resuscitation. The mechanism of sudden death in young Southeast Asian men appears to be ventricular fibrillation. The cause of the arrhythmia is unclear, although in our patients the arrhythmia was not an isolated event; underlying predispositions to further cardiac arrest persisted.

Adult↗
PubMed1983

Prolongation of cardiac refractory times in man by clofilium phosphate, a new antiarrhythmic agent.

The electrophysiologic effects of clofilium phosphate, a new quaternary ammonium antiarrhythmic agent, were evaluated in 15 patients with a variety of cardiac dysrhythmias. Ten patients had ventricular dysrhythmias and five patients had supraventricular dysrhythmias. Clofilium was administered as a single bolus intravenously in doses ranging from 60 to 300 micrograms/kg during electrophysiologic testing. Blood pressure and heart rate were unchanged, and there were no significant side effects. Conduction time was unchanged in atrial tissue, ventricular tissue, atrioventricular node, and in the His-Purkinje system. QT intervals lengthened, atrial effective refractory period increased, and ventricular effective refractory period increased. The effective refractory period of the AV node was unchanged. Refractoriness of the bundle branches or His-Purkinje system was increased in eight patients. Inducible supraventricular arrhythmias were improved in four of four patients, and inducible ventricular arrhythmias were improved in at least five of nine patients. Clofilium is a model for an antiarrhythmic drug which should be useful in interrupting or suppressing reentrant arrhythmias because it increases refractoriness without major changes in conduction time.

Adult↗
PubMed1983

Service factors and health status of survivors of out-of-hospital cardiac arrest.

To determine how emergency service factors affect the health status of survivors of out-of-hospital cardiac arrest, 424 survivors were studied six months later. The principal research tool was the Sickness Impact Profile (SIP), a behaviorally-based instrument for measuring sickness-related dysfunction. Time to initiation of care and time to definitive care were significantly related to dysfunction. The critical time intervals can be influenced by the manner in which communities provide emergency care.

Emergency Medical Services↗
PubMed1983

Neurologic recovery after out-of-hospital cardiac arrest.

A retrospective cohort study of the neurologic sequelae of out-of-hospital cardiac arrest was done using 459 consecutive patients resuscitated and admitted to a teaching hospital over 10 years. Awakening was defined as having comprehensible speech or following commands. One hundred and eighty patients (39%) never awakened and 279 (61%) awakened, 188 without and 91 with persistent neurologic deficits. Fifty-nine patients had cognitive deficits and 32 patients had motor and cognitive deficits. Patients who did not awaken died, with a median survival of 3.5 days. The longer a patient survived without awakening, the smaller the probability of ever awakening and awakening without deficits. Fourteen patients awakening after 4 days had some deficits, and after 14 days six had severe deficits. Neurologic sequelae of cardiac arrest are common and related to awakening. The probability of future awakening and neurologic sequelae for patients not awake at specific times after cardiac arrest can be estimated.

Adolescent↗
PubMed1982

Hypokalemia after resuscitation from out-of-hospital ventricular fibrillation.

We studied serum electrolyte levels, blood gas values, and diuretic history in 115 patients immediately after resuscitation from out-of-hospital ventricular fibrillation. Comparisons were made with 84 patients admitted for acute myocardial infarction and with 88 ambulatory patients with coronary heart disease. Admission serum potassium values of 3.60 mEq/L or lower were found in 56 (49%) of the resuscitated patients, compared with 16 (19%) and eight (9%) of the comparison groups, respectively. In the resuscitated patients, the mean serum potassium level was 3.70 +/- 0.72 (SD) mEq/L, compared with 4.09 +/- 0.66 and 4.17 +/- 0.35 mEq/L in the respective comparison groups. Reduced serum potassium concentration was not related to simple extracellular alkalosis. However, the absence of a causative relationship to diuretic use suggested that it occurred during cardiac arrest and resuscitation. Rapid correction of extracellular acidosis by bicarbonate therapy and ventilation may have produced a shift of extracellular potassium into the intracellular compartment even in the absence of extracellular alkalosis.

Bicarbonates↗
PubMed1982

Ventricular defibrillation -- a comparative trial using 175-J and 320-J shocks.

We compared the effects of initial electrical shocks using 175 and 320 J (joules) in 249 patients with ventricular fibrillation. Survival was unrelated to the energy level used for defibrillation. Reversion to an organized rhythm occurred in a similar proportion of both treatment groups after one or two shocks. The rhythm identified after the first shock was related to outcome (the survival rate was 42 per cent in patients with supraventricular rhythm, 30 per cent in persistent ventricular fibrillation, 26 per cent in idioventricular rhythm, and 14 per cent in asystole; P less than 0.02). Fibrillation recurred in 68 per cent of patients who had been initially defibrillated to an organized rhythm. Repeated shocks at the higher energy level resulted in a higher incidence of atrioventricular block after defibrillation (24 per cent of patients receiving 320 J and 9 per cent of those receiving shocks of lower energy; P less than 0.005). Patients who survived required fewer shocks than patients who later died in the hospital (2.6 shocks as compared with 3.6; P less than 0.005). We conclude that initial defibrillatory shocks using 175 J are as safe and effective as shocks of nearly twice that energy level.

Electric Countershock↗
PubMed1982

Community-based cardiopulmonary resuscitation: what have we learned?

During the past 9 years, more than 175,000 residents of Seattle have received basic training in cardiopulmonary resuscitation (CPR). On the basis of experience in that city and of observations from three other communities, there is little doubt that early initiation of CPA by a bystander is associated with a substantially improved survival. In one year, 43% of patients (47/109) found in a state of ventricular fibrillation survived to hospital discharge when bystanders initiated CPR. In comparison, only 21% (43/207) lived when CPR was delayed until fire department personnel arrived on the scene (p less than 0.001). As expected, there are questions regarding community CPR programs, particularly concerning the level of skills attained and retained. However, in the setting of a rapid-response emergency-care system, we have been unable to relate survival to the apparent quality of CPR as judged by the bystanders' training and occupation or by assessment of what was done on the scene. This discrepancy is likely related to the rapid initial response of the fire department, averaging 3 minutes from dispatch to arrival on the scene. It is important to emphasize that CPR is almost always a temporizing measure and that most victims who require CPR will also need defibrillation, special airway management, and administration of medications. In patients with out-of-hospital ventricular fibrillation, the factors that determine survival are predominantly related to the rapidity with which care is provided, namely, the time from collapse to initiation of CPR and the time to provision of advanced life-support measure. In many communities a 50% survival rate from ventricular fibrillation is probably attainable. Further improvement might accrue from the extensive deployment of inexpensive defibrillators capable of detecting ventricular fibrillation and suitable for use by the general public.

Adult↗
PubMed1982

Ambulatory arrhythmias in resuscitated victims of cardiac arrest.

One hundred forty-four patients with coronary heart disease previously resuscitated from out-of-hospital ventricular fibrillation underwent 24-hour ambulatory ECG monitoring 5 months (median) after cardiac arrest. Patients were then followed for an average of 31.7 months. Fifty-one patients died, 32 from subsequent unexpected cardiac arrest. One hundred twenty-nine patients (90%) had uniform ventricular ectopy. Two-thirds had complex ventricular ectopy (Bigeminy/trigeminy, repetitive forms or frequent multiforms). Complex ectopy, present in 20% or more of the 30-minute recording intervals, occurred in 18 of the patients (56%) who developed subsequent cardiac arrest, compared with 26 of 92 (28%) who survived (P less than 0.005, specificity 72%, relative risk 2.3). Other forms of ventricular ectopy, e.g., uniform, multiform and repetitive beats, were more sensitive but less specific predictors of death or recurrent ventricular fibrillation. Complex ventricular ectopy was associated with certain clinical histories: it occurred in 95% of patients with a history of congestive heart failure and in 79% with remote myocardial infarction, compared with 59% and 56% without these histories (p less than 0.001 and p less than 0.01). As expected, mortality was also greater in patients who had these clinical characteristics. Complex ectopy was related to mortality regardless of the clinical history.

Ambulatory Care↗
PubMed1982

Evaluation of noninvasive tests of cardiac damage in suspected cardiac contusion.

Nonpenetrating trauma to the chest can result in cardiac damage that may be overlooked because of associated injuries and the lack of obvious thoracic injury. The clinical diagnosis of important cardiac damage in this setting is difficult. We evaluated noninvasive tests for detecting myocardial damage in 100 patients with severe, nonpenetrating chest trauma. The noninvasive tests included serial ECG, serial total CPK and CPK-MB enzymes, continuous Holter monitor recording to detect dysrhythmia, and technetium-99m pyrophosphate scintigraphy. Peak CPK-MB elevations occurred in 72 patients. ECG abnormalities were noted in 70 patients, and 27 patients had Lown grade 3 or greater dysrhythmias. Fifteen patients died and all had autopsies. The noninvasive abnormalities were nonspecific and did not reflect myocardial contusion that led to clinically important cardiac complications.

Adolescent↗