Short communication: Influence of an aqueous myrrh suspension on yogurt culture bacteria over yogurt shelf life.

Myrrh is an essential oil and natural flavoring approved by the US Food and Drug Administration, and it has antibacterial and antifungal activity against pathogens. Our objective was to determine the effect of an aqueous myrrh suspension on Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus counts in peptone solution and yogurt, as well as pH and titratable acidity of yogurt during 5 wk of storage at 1 to 4°C. The myrrh suspension (10% wt/vol) was prepared and incorporated into a pure culture dilution in peptone and into yogurt mix at a 1% (vol/vol) level. A control with no myrrh was also prepared, and 3 replications were conducted. Streptococcus thermophilus were enumerated using Streptococcus thermophilus agar with aerobic incubation at 37°C for 24 h, and Lactobacillus delbrueckii ssp. bulgaricus were enumerated using de Man, Rogosa, and Sharpe agar adjusted to pH 5.2, with anaerobic incubation at 43°C for 72 h. During the 8-h period after inoculation, S. thermophilus and L. delbrueckii ssp. bulgaricus counts in peptone solution at 37°C and 43°C, respectively, were not significantly different in the presence or absence of the aqueous myrrh suspension. Counts of S. thermophilus in yogurt containing myrrh (mean ± SD; 4.96 ± 0.58 log cfu/mL) were not significantly different from those in the control yogurt (4.87 ± 0.39 log cfu/mL). The log counts for L. delbrueckii ssp. bulgaricus in yogurt containing myrrh (5.04 ± 1.44 log cfu/mL) and those of the control (5.52 ± 1.81 log cfu/mL) did not differ, and the counts remained within 1 log of each other throughout 5 wk of storage. The pH of the yogurts containing the aqueous myrrh suspension was not significantly different from that of the control yogurts, and their pH values were within 0.1 pH unit of each other in any given week. Titratable acidity values remained steady around 1.1 to 1.2% lactic acid for both yogurt types throughout the storage period, with no significant differences between them. Yogurt culture bacteria can survive in the presence of a myrrh suspension in yogurt with no significant change in pH or titratable acidity. Therefore, it may be beneficial to add an aqueous myrrh suspension to yogurt.

Mexican Queso Chihuahua: functional properties of aging cheese.

Queso Chihuahua, a semi-hard cheese manufactured from raw milk (RM) in northern Mexico, is being replaced by pasteurized milk (PM) versions because of food safety concerns and the desire for longer shelf life. In this study, the functional traits of authentic Mexican Queso Chihuahua made from RM or PM were characterized to identify sources of variation and to determine if pasteurization of the cheese milk resulted in changes to the functional properties. Two brands of RM cheese and 2 brands of PM cheese obtained in 3 seasons of the year from 4 manufacturers in Chihuahua, Mexico, were analyzed after 0, 4, 8, 12, and 16 wk of storage at 4°C. A color measurement spectrophotometer was used to collect color data before and after heating at 232°C for 5 min or 130°C for 75 min. Meltability was measured using the Schreiber Melt Test on samples heated to 232°C for 5 min. Sliceability (the force required to cut through a sample) was measured using a texture analyzer fitted with a wire cutter attachment. Proteolysis was tracked using sodium dodecyl sulfate-PAGE. Compared with PM cheeses, RM cheeses showed less browning upon heating, melted more at 232°C, and initially required a greater cutting force. With aging, cheeses increased in meltability, decreased in whiteness when measured before heating, and required less cutting force to slice. Seasonal variations in the cheesemilk had minimal or no effect on the functional properties. The differences in the functional properties can be attributed, in part, to the mixed microflora present in the RM cheeses compared with the more homogeneous microflora added during the manufacture of PM cheeses. The degree of proteolysis and subsequent integrity of the cheese matrix contribute to melt, slice, and color properties of the RM and PM cheeses. Understanding the functional properties of the authentic RM cheeses will help researchers and cheesemakers develop pasteurized versions that maintain the traditional traits desired in the cheeses.

Effect of pressure and fat content on particle sizes in microfluidized milk.

Average diameters and particle size distributions in fluid milks with different fat contents and subjected to various homogenization pressures with a "microfluidizer" were evaluated. Skim, 2%, and whole milks were microfluidized at 50, 100, 150, and 200 MPa. Cream containing 41% milk fat was microfluidized at 50, 100, and 150 MPa. Particle sizes were determined by laser light scattering. As microfluidization pressure was increased from 50 to 100 MPa, particle sizes in skim, 2%, and whole milks decreased. Microfluidization at pressures greater than 100 MPa had little additional effect on reducing the particle sizes in skim and 2% milks compared with microfluidization at 100 MPa, but the particle sizes in whole milk increased as the microfluidization pressure was increased from 100 to 200 MPa due to formation of homogenization clusters. The particle sizes in cream increased as the microfluidization pressure was increased from 50 to 150 MPa. When the microfluidization pressure was held constant, the particle sizes increased as the milk fat concentration was increased. The coefficients of variations of the volume-weighted particle size distributions for cream were higher than for skim, 2%, and whole milks. Larger "big" particles and smaller "small" particles were formed in whole milk after microfluidization at 200 MPa than at 100 MPa. Although microfluidization can be used to produce small particles in skim, 2%, and whole milks, a higher than optimum pressure (above 100 MPa) applied to whole milk will not lead to the minimum d(43) (volume-weighted average diameter) due to formation of clusters.

Properties of frozen dairy desserts processed by microfluidization of their mixes.

Sensory properties and rate of meltdown of nonfat (0% fat) and low-fat (2% fat) vanilla ice creams processed either by conventional valve homogenization or microfluidization of their mixes were compared with each other and to ice cream (10% fat) processed by conventional valve homogenization. Mixes for frozen dairy desserts containing 0, 2, and 10% fat were manufactured. Some of the nonfat and low-fat ice cream mixes were processed by microfluidization at 50, 100, 150, and 200 MPa, and the remaining nonfat and low-fat ice cream mixes and all of the ice cream mix were processed by conventional valve homogenization at 13.8 MPa, first stage, and 3.4 MPa, second stage. The finished frozen and hardened products were evaluated at d 1 and 45 for meltdown rate and for flavor and body and texture by preference testing. Nonfat and low-fat ice creams that usually had a slower meltdown were produced when processing their mixes by microfluidization instead of by conventional valve homogenization. Sensory scores for the ice cream were significantly higher than sensory scores for the nonfat and low-fat ice creams, but the sensory scores for the conventional valve homogenized controls for the nonfat ice cream and low-fat ice cream were not significantly different from the sensory scores for the nonfat ice cream and low-fat ice cream processed by microfluidization of the mixes, respectively. Microfluidization produced nonfat and low-fat ice creams that usually had a slower meltdown without affecting sensory properties.

Circadian variation in sudden cardiac death: effects of age, sex, and initial cardiac rhythm.

STUDY OBJECTIVE: Previous studies based on data obtained from vital statistics records have demonstrated circadian variation in the occurrence of sudden cardiac death. The purpose of this study was to examine the effects of age, sex, and initial cardiac rhythm on circadian variability in sudden cardiac death. METHODS: This study employed a retrospective analysis of the records of adult patients with witnessed cardiac arrest who underwent resuscitation in an urban paramedic system during a 5-year period. RESULTS: The records of 2,250 consecutive patients with witnessed cardiac arrest were reviewed. Spectral analysis was used to decompose the data into frequency components. A circadian variation in the occurrence of sudden cardiac death was demonstrated, with a low occurrence rate between midnight and 6 AM and a 2.4-fold increase between the rate at 6 AM and the rate at noon. The same circadian pattern was noted among both men and women, among both patients aged 18 to 70 and those older than 70 years, and among patients with various initial cardiac arrest rhythms (ventricular tachycardia or fibrillation, asystole, and electromechanical dissociation). However, the outcome of resuscitation in these patients (ie, the rate of successful resuscitation and the rate of survival) did not demonstrate circadian variation. CONCLUSION: Witnessed out-of-hospital sudden cardiac death demonstrated circadian variation, and this variability was observed regardless of the patient's age, sex, or initial cardiac arrest rhythm. The outcome of resuscitation did not show circadian variability. These results suggest a common pathophysiologic mechanism leading to sudden cardiac death.

Ultrasonographic examination by emergency physicians of patients at risk for ectopic pregnancy.

OBJECTIVE: To evaluate a diagnostic protocol that includes the early use of endovaginal sonography (EVS) by emergency physicians of patients at risk for ectopic pregnancy. METHODS: During this prospective study, pregnant patients > or = 18 years old and at risk for ectopic pregnancy were assessed. Emergency physicians who had completed a training program performed EVS on a convenience sample of eligible women. Clinical disposition was based on predetermined clinical, laboratory, and ultrasonographic criteria. The EVS examinations were reviewed on video by a gynecologist whose interpretation was correlated with the emergency physician EVS readings and with the final clinical diagnoses. Quantitative serum beta-human chorionic gonadotropin (beta hCG) levels were determined for patients who had no definite intrauterine pregnancy (IUP) on EVS. RESULTS: Of 152 patients studied during a 12-month period, four were lost to follow-up. Emergency physician ultrasonographic diagnoses included: definite IUP, 87/148 (59%); probable abnormal IUP, 17/148 (11%); definite ectopic pregnancy, 3/148 (2%); and no definite IUP, 41/148 (28%). The gynecologist agreed with 93% of the initial interpretations. Twelve of 16 patients who had the final diagnosis of ectopic pregnancy were admitted from the ED with this diagnosis. The ultrasonographic diagnosis of the other four was no definite IUP, and no mass or free fluid. For the latter four patients, the presenting serum beta hCG level was < 2,000 mIU/mL (First International Reference Preparation). They were diagnosed as having ectopic pregnancy after serial outpatient EVS and beta hCG measurements. CONCLUSIONS: The application of EVS to emergency practice appears promising. Emergency physicians trained in its use and who apply this diagnostic tool in conjunction with a defined protocol can stratify the risk of patients who have the potential for ectopic pregnancy.

Emergency airway management in hanging victims.

STUDY OBJECTIVE: To determine the incidence, demographics, clinical indicators of survival, and frequency of cervical-spine fractures to define appropriate emergency airway management in hanging victims. DESIGN: Medical examiner records, paramedic reports, and emergency department and hospital medical records were reviewed retrospectively for the period January 1, 1978, to January 1, 1990. SETTING: Urban paramedic system with nine receiving hospitals. PARTICIPANTS: A total of 160,724 medical examiner and paramedic records were reviewed to identify a total study population of 306 hanging victims. One hundred eighty-two victims (59%) were found dead at the scene, and the emergency medical system was not notified. An additional 57 (19%) were seen by paramedics and declared dead at the scene. Sixty-seven (22%) were treated and transported to nine receiving EDs; 39 of these 67 received oral or nasal endotracheal intubation. RESULTS: The incidence of hanging was 0.19% of all medical examiner cases and paramedic runs during the 12-year study. Those hanging victims who survived to receive paramedic transport and treatment by physicians were typically male and attempted suicidal hanging in a public place (most frequently jail) with available bedding or clothes. No hanging victim treated and transported by paramedics had documentation of cervical-spine or spinal cord injury. CONCLUSION: In nonjudicial hanging victims seen by paramedics and transported to an ED, cervical-spine injury is rare. Cerebral hypoxia rather than spinal cord injury is the probable cause of death and should be the primary concern in treatment of this patient population. Following external stabilization of the neck, nasal or oral endotracheal intubation is appropriate emergency airway management in hanging victims.

Continuous pulse oximetry during emergency endotracheal intubation.

STUDY OBJECTIVE: To determine whether continuous pulse oximetry improves the recognition and management of hypoxemia during emergency endotracheal intubation. DESIGN: A prospective, serial 14-month study. SETTING: Emergency department, Level I trauma center. TYPE OF PARTICIPANTS: All adult patients requiring emergency intubation for whom data collection would not compromise patient care. INTERVENTIONS: All samples were obtained from a finger site at a five-second sampling interval and stored in computer memory. Patients were intubated by the nasotracheal or orotracheal route. MEASUREMENTS AND MAIN RESULTS: One hundred ninety-one consecutive adult patients qualified for the study and 211 intubation attempts were analyzed. Hypoxemia (O2 saturation, less than 90%) occurred during an intubation attempt in 30 of 111 nonmonitored versus 15 of 100 monitored attempts (P < .05), and the duration of severe hypoxemia (O2 saturation, less than 85%) was significantly greater for nonmonitored attempts (P < .05). CONCLUSION: Continuous pulse oximetry monitoring reduces the frequency and duration of hypoxemia associated with emergency intubation attempts.

Abdominal vascular trauma: a review of 106 injuries.

A retrospective analysis of acute abdominal vascular injuries was performed to review outcome variables and treatment principles. The authors review their most recent 5-year experience with 106 major abdominal vascular injuries in 64 patients treated at a combined Army and Air Force urban medical center. The majority of the patients were young men who sustained penetrating injuries. There were 41 (64%) gunshot wounds, 17 (27%) stab wounds, and 6 (9%) sustained blunt trauma. Forty-five patients (71%) came to the hospital in shock. The inferior vena cava in 26 patients (41%) and the aorta in 11 patients (17%) were injured most frequently. Suture repair was possible in 53 (50%) injuries. Ligation was performed in 41 (39%). Overall mortality for the series was 39 per cent. Hemorrhagic shock was the cause of death in 23 patients (92%) with only two late deaths. Transfusion requirement, presence of shock, and number of vessels injured all affected outcome. Immediate stabilization in the emergency department includes appropriate crystalloid and blood product resuscitation with minimal delay for diagnostic studies. Prompt abdominal exploration to control hemorrhage and particular attention to factors associated with coagulopathy remain the key elements in saving the lives of these severely injured patients.

Feasibility of prehospital r-TPA therapy in chest pain patients.

STUDY OBJECTIVE: The purpose of this study was to determine the number of eligible prehospital thrombolytic candidates and to estimate the potential time saved if field thrombolysis had been initiated in a series of prehospital chest pain patients. DESIGN AND SETTING: Prehospital 12-lead ECGs were obtained by paramedics during initial evaluation of chest pain patients and stored in the computerized ECG. Prehospital 12-lead ECGs, prehospital charts, and hospital charts then were reviewed retrospectively for final hospital diagnosis, prehospital and emergency department times, and historical exclusion criteria for prehospital treatment with recombinant tissue-type plasminogen activator (r-TPA). TYPE OF PARTICIPANTS: One hundred fifty-seven stable adult prehospital patients with a chief complaint of nontraumatic chest pain were enrolled. Six patients were excluded. Two had unretrievable 12-lead ECGs, and four refused paramedic transport and thus provided no further data. There were complete data on 151 patients making up the final study population. INTERVENTIONS: Prehospital care was unaltered except for acquisition of 12-lead ECGs. No prehospital thrombolytic therapy was administered during this study. MEASUREMENTS AND MAIN RESULTS: The incidence of r-TPA exclusion criteria was as follows: 45 patients (29%) were 75 years of age or older, 57 (38%) had chest pain for more than six hours, 24 (16%) had hypertension with blood pressure of more than 180/110 mm Hg, and six (4%) had a history of a cerebrovascular accident. The time from paramedic scene arrival to prehospital ECG (8.4 +/- 5.1 minutes) was significantly shorter than the time from ED arrival to ED ECG (24.2 +/- 21.6 minutes, P less than .001). Prehospital ECGs increased paramedic scene time over a retrospective control by 5.2 minutes. Mean time from prehospital ECG to ED ECG (potential time saved) was 50.2 + 22.4 minutes in all patients and 43.4 +/- 7.7 minutes in patients with a final diagnosis of acute myocardial infarction (P = NS). Thirteen of 151 patients (8.6%) had prehospital ECGs diagnostic for acute myocardial infarction; eight of these (5.3% overall) met criteria for prehospital r-TPA therapy. CONCLUSION: Prehospital 12-lead ECGs provide an ECG diagnosis 40 to 50 minutes earlier than ED ECGs. However, with current exclusion criteria, the number of prehospital r-TPA candidates is limited.

Prehospital bicarbonate use in cardiac arrest: a 3-year experience.

The American Heart Association no longer recommends the routine use of sodium bicarbonate in cardiac arrests. Reasons cited include the lack of documented effect on clinical outcome and potential adverse effects of metabolic alkalosis and hypernatremia. We reviewed 36 months of experience with 619 nontrauma adult, prehospital cardiac arrest patients to identify 273 successful resuscitations who had emergency department blood gases and electrolytes performed. Determination of complications associated with prehospital intravenous sodium bicarbonate and its impact on survival in resuscitated patients was undertaken. Fifty-eight patients did not receive sodium bicarbonate (NO HCO3 group) and had short cardiopulmonary resuscitation (CPR) times (7.4 +/- 5.5 minutes). Two hundred fifteen patients did receive sodium bicarbonate (HCO3 group) and had significantly longer CPR times (23.3 +/- 13.5 minutes, P less than or equal to .001). Both groups demonstrated routine early chest compression and hyperventilation as evidenced by no significant difference in paramedic response time or rate of intubations. Initial emergency department blood gas results of both groups were not significantly different. No patients in the NO HCO3 group had hypernatremia (sodium [Na]+ greater than 150), whereas four patients (2%) in the HCO3 group were hypernatremic. Eight patients (14%) in the NO HCO3 group and 37 patients (17%) in the HCO3 group were alkalotic with pH values greater than 7.49 (P = NS). Six patients (10%) of the NO HCO3 group and 24 patients (11%) of the HCO3 group had a metabolic component to the alkalosis as defined by a positive base excess value (P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Prehospital prophylactic lidocaine does not favorably affect outcome in patients with chest pain.

STUDY OBJECTIVES: The purpose of our study was to determine the morbidity and mortality in initially stable patients presenting to paramedics with chest pain; to examine possible beneficial effects of its use, including reduction of sudden death syndrome in the prehospital and emergency department setting; and to determine if prophylactic lidocaine is associated with adverse effects in this patient population. DESIGN AND SETTING: This was a randomized, prospective study using prophylactic lidocaine in patients complaining of chest pain who presented to our paramedic system between January 1984 and January 1988. TYPE OF PARTICIPANTS: All patients aged 18 years or older with chest pain of suspected cardiac origin who presented to paramedics during the study period were included. Excluded were patients presenting with warning arrhythmias, second- or third-degree heart block, bradycardias of less than 50, hypotension of less than 90 mm Hg systolic, or known allergy to lidocaine. INTERVENTIONS: Patients were randomized into two groups, the lidocaine-treated group and the control group. An initial bolus of 1 mg/kg IV lidocaine was administered to the lidocaine-treated group. A simultaneous 2 mg/min IV drip was established. Ten minutes after the first dose of lidocaine, a second bolus of 0.5 mg/kg was administered. MEASUREMENTS AND MAIN RESULTS: During the study period, 1,427 patients were entered; 704 received lidocaine, and 723 did not. Discharge diagnoses included acute myocardial infarction (31%), unstable angina (33%), other cardiac problems (7%), and noncardiac problems (29%); overall mortality rate was 7.4%. There was an equal distribution of deaths between the lidocaine-treated group (57) and the control group (48). Six patients had a cardiac arrest in the prehospital setting, and 15 had a cardiac arrest in the ED. Malignant ventricular arrhythmias as the precipitating arrest rhythm in patients with acute myocardial infarctions were similar for the lidocaine-treated and control groups. The incidence of adverse effects, including hypotension, bradycardias, second- or third-degree heart blocks, tinnitus, and altered mental status, was similar in both groups. CONCLUSION: There are no benefits from the administration of prehospital prophylactic lidocaine in stable patients with chest pain; therefore, routine use in this setting appears unwarranted.

The diagnostic impact of prehospital 12-lead electrocardiography.

STUDY HYPOTHESIS: It is feasible to apply prehospital 12-lead electrocardiography to most stable prehospital chest pain patients. Prehospital diagnostic accuracy is improved compared with single-lead telemetry. POPULATION: One-hundred sixty-six stable adult patients who sought paramedic evaluation for a chief complaint of nontraumatic chest pain. METHODS: One-hundred fifty-one prehospital 12-lead ECGs of diagnostic quality were obtained by paramedics on 166 adult patients presenting with nontraumatic chest pain. Paramedics and base station physicians were blinded to the information on acquired prehospital 12-lead ECGs and treated patients according to current standard of care-clinical diagnosis and single-lead telemetry. Final hospital diagnoses were classified into three groups: acute myocardial infarction (24); suspected angina or ischemia (61); and nonischemic chest pain (66). Paramedics and base station physicians' clinical diagnoses and prehospital and emergency department ECGs were similarly classified and compared. Prehospital and ED 12-lead ECGs were read retrospectively by two cardiologists. RESULTS: Paramedics achieved a high success rate (98.7%) in obtaining diagnostic quality prehospital 12-lead ECGs in 94.6% of eligible prehospital patients. For patients with acute myocardial infarction, prehospital ECG alone had significantly higher specificity than did the paramedic clinical diagnosis (99.2% vs 70.9%; P less than .001), and significantly higher positive predictive value (92.9% vs 32.7%; P less than .001). For patients with angina, combining the paramedic clinical diagnosis and the prehospital ECG significantly improved sensitivity (90.2% vs 62.3%; P less than .001) and increased negative predictive value (88.9% vs 71.3%; P less than .02) compared with paramedic clinical diagnosis alone. There was a high concordance between prehospital and ED ECG diagnosis (99.3% for acute myocardial infarction and 92.8% for angina). Furthermore, ten patients whose prehospital ECGs demonstrated ischemia and who had final hospital diagnoses of angina or acute myocardial infarction were mistriaged by paramedics and/or received no base station physician-directed therapy. CONCLUSION: It is feasible to apply prehospital 12-lead electrocardiography to most stable prehospital chest pain patients. Prehospital 12-lead ECGs have the potential to significantly increase the diagnostic accuracy in chest pain patients, approach congruity with ED 12-lead ECG diagnoses, and may allow for consideration of altering and improving prehospital and hospital-based management in this patient population.

50% dextrose: antidote or toxin?

The empiric administration of 50% dextrose to all patients presenting to the ED with altered mental status is a standard of care predicated on the assumption that glucose administration is harmless to nonhypoglycemic patients. Considerable evidence now disputes this assumption. Glucose administration before complete cerebral ischemia in experimental animals worsens neurologic and histologic outcome. Administration of glucose during severe incomplete ischemia has a similar detrimental effect. The translation of these experimental findings into clinical practice has been slow, perhaps hindered by the frequent use of rodent models and large bolus doses of glucose. However, evidence is now provided by primate and human studies and by experimental designs using clinically relevant doses of glucose. These clinical and experimental findings in conjunction with the wide availability of a rapid bedside screen for hypoglycemia provide the rationale for an alteration in the standard of care. The empiric administration of glucose should be avoided in patients at risk of cerebral ischemia, such as those with acute stroke, impending cardiac arrest, or severe hypotension or receiving CPR. A bedside fingerstick blood glucose estimation should be performed immediately on all patients presenting with altered mental status. The administration of 50% dextrose should be reserved for those patients in whom hypoglycemia is demonstrated; this practice will uphold Hippocrates' most basic principle of clinical medicine, "The physician must...do no harm."

50% dextrose: antidote or toxin?

The empiric administration of 50% dextrose to all patients presenting to the ED with altered mental status is a standard of care predicated on the assumption that glucose administration is harmless to non-hypoglycemic patients. Considerable evidence now disputes this assumption. Glucose administration before complete cerebral ischemia in experimental animals worsens neurologic and histologic outcome. Administration of glucose during severe incomplete ischemia has a similar detrimental effect. The translation of these experimental findings into clinical practice has been slow, perhaps hindered by the frequent use of rodent models and large bolus doses of glucose. However, evidence is now provided by primate and human studies and by experimental designs using clinically relevant doses of glucose. These clinical and experimental findings in conjunction with the wide availability of a rapid bedside screen for hypoglycemia provide the rationale for an alteration in the standard of care. The empiric administration of glucose should be avoided in patients at risk for cerebral ischemia, such as those with acute stroke, impending cardiac arrest, or severe hypotension or receiving CPR. A bedside fingerstick blood glucose estimation should be performed immediately on all patients presenting with altered mental status. The administration of 50% dextrose should be reserved for those patients in whom hypoglycemia is demonstrated; this practice will uphold Hippocrates' most basic principle of clinical medicine, "The physician must ... do no harm."

Prehospital experience with defibrillation of coarse ventricular fibrillation: a ten-year review.

Early defibrillation of patients with coarse ventricular fibrillation has been implicated as a predictor of survival in prehospital cardiac arrest. A retrospective study of our experience with prehospital defibrillation was conducted to define the relationship between rapid delivery of first countershock and survival, determine whether a relationship exists between the number of countershocks delivered and the save rate, and assist clinicians with general guidelines for termination of advanced life support efforts in the presence of ventricular fibrillation refractory to multiple defibrillation attempts. During the ten-year study period, adult, nontraumatic, nonpoisoned, witnessed arrests with an initial rhythm of coarse ventricular fibrillation were reviewed. Of 1,497 patients, 25% survived, 13% were paramedic-witnessed (PW) arrests, and 87% were non-paramedic-witnessed (NPW) arrests. The mean PW shock time, defined as time from arrest to first shock, was 1.6 +/- 3.7 minutes with a save rate of 37%. The mean NPW shock time was 10.2 +/- 5.1 minutes with a save rate of 23% (P less than or equal to .001). Thirty-two percent of PW arrests were converted to a spontaneous rhythm with pulses after the first countershock compared with 9% of NPW arrests (P less than or equal to .001). There was a dramatic decrease in PW arrests obtaining a perfusing rhythm after the first countershock attempt with each minute delay in electrical countershock up to three minutes; a plateau effect was evident after three minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

EMT-defibrillation: the Wisconsin experience.

The survival rate for patients with prehospital cardiac arrest has improved in some communities with early defibrillation by emergency medical technician-defibrillators (EMT-Ds). In rural areas, previous studies on survival with defibrillation by EMT-Ds have been variable. We conducted an EMT-D study to determine effectiveness in various prehospital settings. Sixty-four ambulance services from communities ranging in size from rural areas to city suburbs participated in our prospective study. EMTs were trained in rhythm recognition and the use of a manual defibrillator during a standardized 20-hour course. Over 18 months, data were collected locally for central analysis. Five hundred sixty-six patients with primary cardiac arrest were included in our study: 36 (6.4%) survived. Retrospective review revealed survival before EMT-D implementation to be 3.6% (P less than .02). Three hundred four patients (54%) had an initial rhythm of ventricular fibrillation, with 33 (11%) surviving. The survival rate for EMT-D-witnessed arrest with an initial rhythm of ventricular fibrillation was 42%. Patients with asystole were countershocked in our study; however, there were no survivors from this group. The neurologic status of survivors at time of hospital discharge was normal in 72%. The average response time, defined as time of emergency medical services activation to the time of EMT-D arrival, was 7.3 +/- 5.8 and 3.7 +/- 2.0 minutes for nonsurvivors and survivors, respectively (P less than .002). There were no survivors when the response time was more than eight minutes.(ABSTRACT TRUNCATED AT 250 WORDS)