Biomedical subjects

M K Copass

Publications and source records attributed to M K Copass.

At least 55 records · Page 3Linked to original sources

PubMed1987

Impact of drug screening in suspected overdose.

We studied how emergency qualitative drug screens were ordered and used during the evaluation of 405 consecutive adult patients presenting to a metropolitan emergency department with suspected drug intoxication. Physicians completed a two-part questionnaire outlining diagnosis, diagnostic certainty, suspected drug(s), and management plans immediately following initial evaluation and again at the time of ED disposition. Screen results were reviewed prior to ED disposition in 361 (89%) cases. We found that qualitative drug screens were associated with substantial changes in diagnostic certainty, as measured by changes in probability estimates and changes in absolute mean log-likelihood ratios. In 196 cases for which all data were recorded prospectively, drug screens excluded a diagnosis of drug intoxication or specifically suspected drugs in 81 cases (41%), but identified previously unsuspected drugs in only 21 cases (11%, P less than .001). Management changes followed qualitative drug screen results in 16 of 361 cases overall (4.4%), but seven of these were also associated with diagnostic quantitative serum drug levels. Potentially critical interventions were begun in two cases following positive screens but delayed in another due to a falsely negative screen. Guidelines for more efficient test utilization are proposed.

Emergencies↗

PubMed1987

Automatic external defibrillators: importance of field testing to evaluate performance.

A new automatic external defibrillator was tested first against a tape-recorded data base of rhythms and then during use by first-responding fire fighters in a tiered emergency system. The sensitivity for correctly classifying ventricular fibrillation and ventricular tachycardia was substantially less during clinical testing in 298 patients than would have been predicted from preclinical results: 52% of ventricular fibrillation analyses in patients were correctly classified versus 88% of episodes in the data base, and 22 versus 86%, respectively, for ventricular tachycardia (p less than 0.001). The detection algorithm was modified and evaluated further in another 322 patients. The modified detector performed substantially better than did the one that had been designed from prerecorded rhythms: with its use, 118 (94%) of 125 patients in ventricular fibrillation were counter-shocked compared with 91 (77%) of 118 similar patients with use of the initial algorithm (p less than 0.001). No inappropriate shocks were delivered. This improvement resulted in a shorter time to first shock (p less than 0.01) and more shocks being delivered for persistent or recurrent episodes of ventricular fibrillation (p less than 0.05). Of 620 patients treated with the automatic defibrillator, 243 (39%) had ventricular fibrillation; 57 (23%) of the 243 regained pulse and blood pressure before paramedics arrived, 141 (58%) were admitted to hospital and 71 (29%) were discharged.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗

PubMed1987

Incidence and effect of hypothermia in seriously injured patients.

Hypothermia is a well recognized consequence of severe injury, even in temperate climates, and the physiologic consequences of hypothermia are known to be detrimental. To analyze the frequency and risk factors for hypothermia and its effect on patient outcome, we prospectively studied 94 intubated injured patients at a regional trauma center during a 16-month period. Esophageal temperature probes were placed in the field or ER and core temperatures (T) were followed for 24 hours or until rewarming. Patients were designated as normothermic (greater than 36 degrees C), mildly hypothermic (34 degrees C-36 degrees C) or severely hypothermic (less than 34 degrees C) based on initial T. The risk factors for hypothermia evaluated included age, severity and location of injuries, blood alcohol level, blood transfusion requirements, and time spent in the field, ER, or OR. The average initial T was 35 degrees C, with no seasonal variation. Injury severity and survival correlated with severe hypothermia. Normothermic patients had an average ISS of 28 with a 78% survival. Severely hypothermic patients had an average ISS of 36 with a 41% survival (p less than 0.05). Patient age strongly correlated with outcome although there was no relationship between age and initial temperature. Sixty-two per cent of patients tested were positive for blood alcohol, and one half were legally intoxicated (BAC greater than 100 mg%). However, no consistent correlation was found between alcohol intoxication and initial temperature or patient survival. Blood transfusion requirements paralleled injury severity and patients receiving greater than 10 unit transfusions had significantly lower core temperature (p less than 0.05). The average temperature change was positive in the ER, OR, and ICU with time to rewarming correlating with the aggressiveness of warming measures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1986

Cardiac arrest treated with a new automatic external defibrillator by out-of-hospital first responders.

Two hundred sixty patients in cardiac arrest were treated with an automatic external defibrillator by first-responding firefighters before arrival of paramedics. On average, first responders arrived 5 minutes before paramedics. Of 118 patients with ventricular fibrillation, 91 (77%) were administered shocks, 21 (23%) of whom had return of pulse and blood pressure by the time paramedics arrived. Fifty-six (62%) were admitted to the hospital and 30 (33%) survived. The survival rate for all 118 victims discovered with ventricular fibrillation was 27%. The device correctly classified the initial and all subsequent rhythms in 92 patients with asystole, 46 with electromechanical dissociation, and 22 others with presumed respiratory arrest; it did not deliver any inappropriate shocks to patients or to the rescuers using the device. An automatic external defibrillator can be used by first responders as an adjunct to basic life support, and its use may improve survival by shortening the time to defibrillation.

Allied Health Personnel↗

PubMed1986

Considerations for improving survival from out-of-hospital cardiac arrest.

Since the implementation of a paramedic system in Seattle, yearly survival rates from out-of-hospital cardiac arrest due to ventricular fibrillation have averaged 25% without any significant increase over the years. Outcome for cardiac arrest associated with other rhythms has been poor: when asystole was the first rhythm recorded, only 1% of patients survived; when electromechanical dissociation was initially present, only 6% survived. For cases of electromechanical dissociation, neither the type of rhythm nor the rate appear to influence outcome. Survival from ventricular fibrillation can be improved by shortening the delay to initiation of CPR and to defibrillation. When outcome in 244 witnessed arrests was related to the times to beginning CPR and to initial defibrillation, mortality increased 3% each minute until CPR was begun and 4% a minute until the first shock was delivered. New strategies that minimize delays appear to have the greatest promise for improving survival after cardiac arrest.

Ambulances↗

PubMed1986

Prehospital management of trauma: a tale of three cities.

The controversies that have surrounded the prehospital management of trauma stem not only from a lack of appropriate evaluation data, but also from a lack of medical accountability and "street-wise," academic physician involvement within emergency medical services (EMS) systems. As a result, the approach to EMS trauma care has often been over-generalized and debated in terms of simplistic, unidimensional concepts, such as "scoop and run" versus "field stabilization," without any regard for the type and anatomic location of injury involved, the efficiency and skill of rescuers, the proximity and actual capabilities of definitive care resources, and the logistics of the prehospital setting. The failure to understand and delineate these variables has led to conflicting studies and has confused the analysis of potential therapeutic modalities and management strategies. In view of this, a survey is provided of three major cities, each with intensive, academic physician involvement in their EMS systems, and the approach and rationale for their prehospital care strategies are summarized. In all three systems, patients generally are categorized according to three major injury types (penetrating, blunt, and thermal) and then further subcategorized with regard to anatomical involvement, specifically those involving potential (or known) internal truncal injuries versus those with isolated head trauma or isolated extremity injury. For all three, high-flow O2 delivery and aggressive, advanced airway management (by endotracheal intubation whenever feasible) are keystones of management. In cases of potential or known internal truncal injury, the priority is also expeditious transport to facilities with definitive surgical care with the establishment of IV access and rapid fluid infusions en route.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1986

Factors influencing survival after out-of-hospital cardiac arrest.

Survival to hospital discharge was related to the clinical history and emergency care system factors in 285 patients with witnessed cardiac arrest due to ventricular fibrillation. Only the emergency care factors were associated with differences in outcome. Both the period from collapse until initiation of basic life support and the duration of basic life support before delivery of the first defibrillatory shock were shorter in patients who survived compared with those who died (3.6 +/- 2.5 versus 6.1 +/- 3.3 minutes and 4.3 +/- 3.3 versus 7.3 +/- 4.2 minutes; p less than 0.05). A linear regression model based on emergency response times for 942 patients discovered in ventricular fibrillation was used to estimate expected survival rates if the first-responding rescuers, in addition to paramedics, had been equipped and trained to defibrillate. Expected survival rates were higher with early defibrillation (38 +/- 3%; 95% confidence limits) than the observed rate (28 +/- 3%). Because outcome from cardiac arrest is primarily influenced by delays in providing cardiopulmonary resuscitation and defibrillation, factors affecting response time should be carefully examined by all emergency care systems.

Aged↗

PubMed1985

Prehospital endotracheal intubation: rationale for training emergency medical personnel.

Endotracheal intubation by emergency medical services (EMS) personnel in the prehospital setting decreases morbidity and helps to improve the outcome of critically ill patients, especially those with cardiac or respiratory arrest, multiple injuries, or severe head trauma. The endotracheal tube facilitates better oxygenation and ventilation because it enhances lung inflation and protects the lungs from aspiration. No other alternative modality is as efficacious. Compared to physicians in general, properly instructed, well-supervised paramedics can be trained to perform this procedure safely and more efficiently in the emergency setting. The use of the endotracheal tube in the prehospital setting should be strongly encouraged and the training of EMS personnel in this skill should be given high priority.

Allied Health Personnel↗

PubMed1985

Amplitude of ventricular fibrillation waveform and outcome after cardiac arrest.

The amplitude of ventricular fibrillation found initially in 394 patients was compared to clinical and logistical findings at the time of cardiac arrest. Peak-to-peak amplitude averaged 0.55 +/- 0.25 mV; a very low amplitude (0.2 mV or less) or "fine" fibrillation was present in 66 patients (17%). The amplitude was not found to be related to clinical histories, but depended on the length of the period from collapse until start of basic life support (p = 0.004) and the delay until assessment by paramedics (p = 0.001). Survival rates were strongly associated with amplitude: only 4 patients (6%) with fine ventricular fibrillation survived, compared to 117 or 328 patients (36%) in whom the initial amplitude was higher (p less than 0.001). Patient outcome related to amplitude even after adjusting for clinical history and logistical delays (p less than 0.005). We conclude that fine ventricular fibrillation is in part the result of delay in initiation of treatment, and that fibrillation amplitude is a powerful indicator of outcome after cardiac arrest.

Aged↗

PubMed1985

Occupational exposure to hepatitis B in paramedics.

To determine their occupational risk for hepatitis B infection, 59 Seattle paramedics were tested for hepatitis B serum markers. Evidence of antibody to hepatitis B surface antigen (anti-HBs) or antibody to hepatitis B core antigen (anti-HBc) was found in 25%, a rate five times that of a similar Seattle population. Seropositivity did not correlate with age, race, clinical history, or length of service. Of the 15 paramedics with seropositivity to hepatitis B virus six initially had low titers of either anti-HBs or anti-HBc. Four of the six demonstrated persistent low-grade seropositivity on retesting. Paramedics are at increased risk of hepatitis B infection. The high frequency of low-titer anti-HBs suggests that frequent low-level exposure to hepatitis B virus occurs in this population; hepatitis B vaccine should be strongly considered for paramedics.

Allied Health Personnel↗

PubMed1984

Treatment of ventricular fibrillation. Emergency medical technician defibrillation and paramedic services.

We compared the effect of rapid defibrillation by emergency medical technicians (EMTs) combined with paramedic care with that of standard EMT and paramedic care on survival from 540 witnessed episodes of out-of-hospital cardiac arrest caused by ventricular fibrillation. More than 400 EMTs were trained in the recognition of ventricular fibrillation and operation of a defibrillator. For a portion of the three-year study, emergency care for 179 cases was randomized between the two types of services. For randomized cases, when the time interval between EMT and paramedic arrival was greater than four minutes there was significantly improved survival with EMT defibrillation and paramedic care (42%) compared with basic EMT and paramedic care (19%). Similar findings occurred when all cases were considered (38% v 18%). Defibrillation by EMTs combined with paramedic services can enhance survival from ventricular fibrillation, compared with basic EMT and paramedic care.

Aged↗

PubMed1984

Prehospital cardiopulmonary resuscitation of the critically injured patient.

Prehospital cardiopulmonary resuscitation combined with endotracheal intubation, vigorous fluid resuscitation, and rapid transport can be effective in resuscitating trauma patients in cardiopulmonary arrest. Survival does not correlate with the injury severity score or transport time once the patient has arrested but does correlate with the mechanism of injury, endotracheal intubation, and placement of intravenous lines.

Adolescent↗

PubMed1984

Urological trauma in the Pacific Northwest: etiology, distribution, management and outcome.

A computer-assisted review identified 184 patients with genitourinary tract injuries among 5,400 hospitalized for trauma. Particular attention was directed to the controversial groups of patients with blunt renal and posterior urethral injuries. Management of renal injuries was based on clinical criteria. Subsequent renal exploration was necessary in only 1 of 115 patients with renal contusions, or simple or deep lacerations who underwent initial expectant management. Followup was available in all patients with severe renal injuries and in 53 per cent with renal contusions or simple lacerations. Parenchymal loss was noted on an excretory urogram in only 1 patient and none suffered hypertension, hydronephrosis or other sequelae. A staged approach was preferable to immediate repair of posterior urethral injuries. Seven patients managed by initial cystostomy drainage followed by secondary urethral repairs did well. Primary realignment was complicated by stricture, incontinence or impotence in 3 of 6 patients.

Accidents, Occupational↗

PubMed1984

The influence of ethanol intoxication on outcome of injured motorcyclists.

Previous reports have failed to demonstrate a statistically significant adverse effect of acute ethanol intoxication in the well-resuscitated trauma patient. In the present study the prevalence of acute alcohol intoxication and its effect on outcome was analyzed in a homogenous population of young, previously healthy motorcycle accident victims (N = 134). The incidence of intoxication was 25%. The intoxicated cyclists were at fault for the accident 50% more often than the nonintoxicated cyclists and were found to wear helmets one third as frequently. Furthermore, the protective effect of helmet use as seen in the nonintoxicated group was lost in the intoxicated group, who sustained head injuries twice as frequently. Only patients with critical head injuries died and, although the ISS levels of those dying were similar in the two groups, the mortality following the critical head injury was twice as high among intoxicated patients (80 vs. 43%). Overall, the intoxicated group had a fourfold increased mortality rate. Thus, although intoxicated motorcyclists comprised 25% of the total population, they represent a mere 9% of the helmet-wearing population, and, in contrast, 39% of the severely head-injured victims and a majority (57%) of the mortality rate.

Accidents, Traffic↗

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

Geriatric trauma: injury patterns and outcome.

Over a 2-year period, 100 consecutive patients more than 70 years of age with multiple injuries were evaluated at a metropolitan trauma center for injury patterns and factors that affected survival. The analysis incorporated mechanism of injury, body region affected, Injury Severity Score, shock, change from level of prehospital function, and mortality. The mortality for the group was 15%. It was found that the Injury Severity Score was not predictive of survival in the elderly injured. However, central nervous system injury (p less than 0.01) and hypovolemic shock (p less than 0.001) were predictive of survival. While 85% of the injured patients survived, 88% of these did not return to their previous level of independence.

Activities of Daily Living↗

PubMed1983

The effects of prehospital trauma care on survival from a 50-meter fall.

One hundred eighty individuals are known to have jumped or fallen from Seattle's Aurora Bridge during the past 49 years. The survival rate has been increasing, as has been the severity of injury experienced by the survivors. Both prehospital resuscitative measures and advances in the overall care of the trauma patients in hospital may have contributed to this. The survival statistics and injury severity scores of this homogeneous group of patients before and after the institution of a sophisticated prehospital emergency medical care program (Medic I) provide historically controlled data on the role of this type of system in the care of trauma patients. More patients who were alive at the scene arrived at the hospital alive after the development of the Medic I program. Overall survival was tripled. Patients with more severe injuries survived. These data demonstrate that prehospital airway control, ventilation, initiation of fluid resuscitation and cardiovascular support by physician-supervised paramedical personnel can significantly benefit multiple trauma patients. In this context, the Medic I approach was superior to the previously existing 'load and go' system.

Accidents↗

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↗