Marginal gap of crowns made with a phosphate-bonded investment and accelerated casting method

BACKGROUND: Most patients undergoing in-hospital cardiac resuscitation will not survive to hospital discharge. OBJECTIVE: To derive a decision rule permitting the discontinuation of futile resuscitation attempts by identifying patients with no chance of surviving to hospital discharge. PATIENTS AND METHODS: Patient, arrest, and outcome data for 1077 adult patients undergoing in-hospital cardiac resuscitation was retrieved from 2 randomized clinical trials involving 5 teaching hospitals at 2 university centers. Recursive partitioning was used to identify a decision rule using variables significantly associated with death in hospital. RESULTS: One hundred three patients (9.6%) survived to hospital discharge. Death in hospital was significantly more likely if patients were older than 75 years (P<.001), the arrest was unwitnessed (P = .003), the resuscitation lasted longer than 10 minutes (P<.001), and the initial cardiac rhythm was not ventricular tachycardia or fibrillation (P<.001). All patients died if there was no pulse 10 minutes after the start of cardiopulmonary resuscitation, the initial cardiac rhythm was not ventricular tachycardia or fibrillation, and the arrest was not witnessed. As a resuscitation rule, these parameters identified all patients who survived to hospital discharge (sensitivity, 100%; 95% confidence interval, 97.1%-100%). Resuscitation could have been discontinued for 119 (12.1%) of 974 patients who did not survive, thereby avoiding 47 days of postresuscitative care. CONCLUSIONS: A practical and highly sensitive decision rule has been derived that identifies patients with no chance of surviving in-hospital cardiac arrest. Prospective validation of the rule is necessary before it can be used clinically.     

Factors influencing CPR outcome in Siriraj Hospital

This prospective study of cardiopulmonary resuscitation was surveyed in Siriraj Hospital from 1 March 1996 to 31 May 1996. In a 3-month-period, 94 resuscitated patients were reported with initial survivors 31 cases (33%) and 3 patients (3%) were alive until discharged from the hospital. Most of the resuscitated patients belonged to the emergency department (47%) with the lowest survival rate (23%). The common causes of cardiac arrest were heart diseases (31%) and respiratory failure (21%). All survivors who were able to be discharged from the hospital had suffered cardiac arrest from heart diseases. After resuscitation, only half of the initial survivors received postarrest care in the intensive care units, the rest remained in general wards and outpatient department. By using logistic regression for multivariate analysis, the survival rate was correlated with locations of CPR, duration of CPR and duration of attempt endotracheal intubation. The initial survival outcome of CPR was not related to sex, age, time of day of CPR, duration of hospitalization before CPR, types of arrhythmia, delay in doctors' arrival and performers of CPR.     

Pediatric cardiopulmonary resuscitation: a collective review

Little information is available about the effects of CPR in children, although it is known that the outcomes are dismal. Examples of unanswered questions include which advanced life support (ALS) procedures should be performed out-of-hospital, whether high-dose epinephrine improves survival, and the true prevalence of ventricular fibrillation as a presenting rhythm. Children differ from adults as to the cause and pathophysiology of cardiopulmonary arrest, but prehospital EMS and hospital resuscitation teams were initially designed for the care of adults. Because pediatric cardiopulmonary arrest is rare, prospective data are difficult to gather, and there are few large published studies. The purpose of this collective review was to review the current body of knowledge regarding survival rates and outcomes in pediatric CPR and, based on this review, to outline a course for future research.     

Endoscopic CO2 laser excision of large or recurrent laryngeal saccular cysts in adults

BACKGROUND: Most paediatric cardiac arrest studies have been conducted in the USA, where paramedics provide prehospital emergency care. We wanted to study the outcome of paediatric cardiac arrest patients in an emergency medical system which is based on physician staffed emergency care units. METHODS: We analysed retrospectively the files of 100 prehospital cardiac arrest patients from Southern Finland during a 10-year study period. The patients were less than 16 years of age. RESULTS: Fifty patients were declared dead on the scene (DOS) without attempted resuscitation, and cardiopulmonary resuscitation (CPR) was initiated in 50 patients. The sudden infant death syndrome was the most common cause of arrest in the DOS patients (68%) as well as in those receiving CPR (36%). Asystole was the initial cardiac rhythm in 70% of the patients in whom CPR was attempted. Resuscitation was successful in 13 patients, 8 of whom were ultimately discharged. Six of the patients survived with mild or no disability and 4 of them had near-drowning aetiology. In multivariate analysis, the short duration of CPR (< or = 15 min) was the only factor significantly associated with better survival. CONCLUSIONS: Although prehospital care was provided by physicians, the overall rate of survival was found to be equally poor as reported from systems with paramedics. The only major difference between physician- and paramedic-staffed emergency care units is the ability of physicians to refrain from resuscitation already on the scene when prognosis is poor.     

Do not resuscitate: an ethical dilemma for the decision-maker

Since its introduction in the 1960s, cardiopulmonary resuscitation (CPR) has been universally available to all hospital patients unless the consultant in charge has specified a 'do not resuscitate' (DNR) order. The public perception of CPR has tended to be one of overoptimism, but this is not matched by the low survival to discharge ratio of approximately 1:10. In addition, there is the risk of prolonging suffering, compared with the quick and relatively painfree alternative offered by cardiac arrest. Decisions about resuscitation pose many ethical dilemmas for those involved and should take into consideration the patient's wishes, prognosis and quality of life.     

Documenting life-support preferences in hospitalized patients

PURPOSE: The purpose of this article was to determine the extent to which patients at high risk of hospital death who undergo cardiopulmonary resuscitation (CPR) have previously had their life support preferences addressed and documented. MATERIALS AND METHODS: We conducted a retrospective chart review of all patients older than 18 years of age hospitalized for more than 24 hours who sustained a cardiac arrest with attempted CPR at our tertiary care university teaching hospital during 1994 (n = 71). We searched all hospital charts specifying ICD-9 codes: Cardiac arrest, ventricular fibrillation, ventricular tachycardia, asystole, electromechanical dissociation, defibrillation, or CPR. Patients were selected if (1) they had a true cardiac arrest (abrupt cessation of spontaneous circulation) and (2) had attempted CPR or defibrillation. Patients were classified as "high risk" if they satisfied at least one of the following: modified prearrest morbidity index > or = 7, moderate/severe dementia, day 1 APACHE II score > 24 or > or = 4 dysfunctional organ systems. RESULTS: We searched 147 charts; of 71 patients meeting inclusion criteria, 53 were high risk. Of patients at high risk of sustaining a cardiopulmonary arrest during the index hospital admission, 3 (6%) had preferences addressed within the first 24 hours of hospitalization, 7 (13%) had delayed discussion of preferences before arrest, 23 (43%) had preferences addressed post arrest, and 20 (38%) had no documented discussions. Of the 23 high-risk patients initially surviving cardiac arrest, all were subsequently given "do not resuscitate" orders. Univariate analysis of factors associated with life-support discussion before cardiac arrest were previous cardiac arrest (OR, 5.9) and APACHE II score > 24 (OR, 1.1), although neither reached statistical significance. None of the 32 patients with a modified PAM index > or = 7 (32 of 71) survived hospitalization. Only 3 patients survived to hospital discharge. CONCLUSIONS: Early communication regarding life-support preferences is important in high-risk patients so that inappropriate or unwanted treatment is not implemented. Given that optimal care includes addressing and documenting life-support preferences in high-risk patients early in their hospitalization, this standard was infrequently met.     

Impact of first-responder defibrillation in an urban emergency medical services system

OBJECTIVE: To evaluate the impact of adding first-responder defibrillation by fire-fighters to an existing advanced life-support emergency medical services system. DESIGN: Nonrandomized, controlled clinical trial with periodic crossover. SETTING: Memphis, Tenn, a city of 610,337 people, which is served by a fire department-based emergency medical services system. All city ambulances provide advanced life support. PATIENTS: Adult victims of out-of-hospital cardiac arrest due to heart disease. INTERVENTION: Twenty of 40 participating engine companies were equipped with an automated external defibrillator and ordered to apply it immediately in all cases of cardiac arrest. The other 20 companies were ordered to start cardiopulmonary resuscitation (CPR) immediately and wait for paramedics to arrive. Every 75 days, group roles were reversed. Care otherwise proceeded according to 1986 American Heart Association guidelines. MAIN OUTCOME MEASURES: Return of spontaneous circulation in the field, survival to hospital admission, survival to hospital discharge, and neurological status at discharge. RESULTS: During the 39-month study interval, 879 patients were treated by a project engine company. Four hundred thirty-one (49%) of these were found in ventricular fibrillation. Bystander CPR was started in only 12% of cases. Overall, firefighters reached the scene a mean of 2.5 minutes faster than simultaneously dispatched paramedics. Although our automated external defibrillators proved to be reliable and efficacious for terminating ventricular fibrillation and pulseless ventricular tachycardia, patients treated by an automated external defibrillator-equipped engine company were no more likely than CPR-treated controls to be resuscitated (32% vs 34%, respectively), to survive to hospital admission (31% vs 29%), or to survive to hospital discharge (14% vs 10%). Neurological outcomes were also similar in the two treatment groups. CONCLUSIONS: In a fast-response, urban emergency medical services system served by paramedics, the impact of adding first-responder defibrillation appears to be small. Early defibrillation alone cannot overcome low community rates of bystander CPR. Careful attention to every link in the "chain of survival" is needed to achieve optimal rates of survival after cardiac arrest.     

Stability of human urinary gonadotropin peptide

OBJECTIVE: To examine the effect of full implementation of advanced skills by ambulance personnel on the outcome from out of hospital cardiac arrest. SETTING: Patients with cardiac arrest treated at the accident and emergency department of the Royal Infirmary of Edinburgh. METHODS: All cardiorespiratory arrests occurring in the community were studied over a one year period. For patients arresting before the arrival of an ambulance crew, outcome of 92 patients treated by emergency medical technicians equipped with defibrillators was compared with that of 155 treated by paramedic crews. The proportions of patients whose arrest was witnessed by lay persons and those that had bystander cardiopulmonary resuscitation (CPR) were similar in both groups. RESULTS: There was no difference in the presenting rhythm between the two groups. Eight of the 92 patients (8.7%) treated by technicians survived to discharge compared with eight of 155 (5.2%) treated by paramedics (NS). Of those in ventricular fibrillation or pulseless ventricular tachycardia, eight of 43 (18.6%) in the technician group and seven of 80 (8.8%) in the paramedic group survived to hospital discharge (NS). For patients arresting in the presence of an ambulance crew, four of 13 patients treated by technicians compared with seven of 15 by paramedics survived to hospital discharge. Only two patients surviving to hospital discharge received drug treatment before the return of spontaneous circulation. CONCLUSIONS: No improvement in survival was demonstrated with more advanced prehospital care.     

Phacoemulsification and posterior chamber intraocular lens implantation in uveitis

The effect of a pure alpha-adrenergic agent, methoxamine on ventricular fibrillation (VF) amplitude and the relation between hemodynamic parameters and survival in a rodent cardiopulmonary resuscitation (CPR) model were studied. Our results suggested that: 1) VF amplitude decreased during untreated VF, but it increased during pericardial chest compression: 2) methoxamine significantly increased the mean aortic pressure (MAP) and coronary perfusion pressure (CPP) but not VF amplitude, and the survival also increased due to elevation of CPP; and 3) all surviving animals with successful defibrillation had a higher VF amplitude.     

Survival after in-hospital cardiopulmonary resuscitation. A meta-analysis

OBJECTIVE: To determine the rates of immediate survival and survival to discharge for adult patients undergoing in-hospital cardiopulmonary resuscitation, and to identify demographic and clinical variables associated with these outcomes. MEASUREMENTS AND MAIN RESULTS: The MEDLARS database of the National Library of Medicine was searched. In addition, the authors' extensive personal files and the bibliography of each identified study were searched for further studies. Two sets of inclusion criteria were used, minimal (any study of adults undergoing in-hospital cardiopulmonary resuscitation) and strict (included only patients from general ward and intensive care units, and adequately defined cardiopulmonary arrest and resuscitation). Each study was independently reviewed and abstracted in a nonblinded fashion by two reviewers. The data abstracted were compared, and any discrepancies were resolved by consensus discussion. For the subset of studies meeting the strict criteria, the overall rate of immediate survival was 40.7% and the rate of survival to discharge was 13.4%. The following variables were associated with failure to survive to discharge: sepsis on the day prior to resuscitation (odds ratio [OR] 31.3; 95% confidence interval [CI] 1.9, 515), metastatic cancer (OR 3.9; 95% CI 1.2, 12. 6), dementia (OR 3.1; 95% CI 1.1, 8.8), African-American race (OR 2. 8; 95% CI 1.4, 5.6), serum creatinine level at a cutpoint of 1.5 mg/dL (OR 2.2; 95% CI 1.2, 3.8), cancer (OR 1.9; 95% CI 1.2, 3.0), coronary artery disease (OR 0.55; 95% CI 0.4, 0.8), and location of resuscitation in the intensive care unit (OR 0.51; 95% CI 0.4, 0.8). CONCLUSIONS: When talking with patients, physicians can describe the overall likelihood of surviving discharge as 1 in 8 for patients who undergo cardiopulmonary resuscitation and 1 in 3 for patients who survive cardiopulmonary resuscitation.     

Learning a motor task involving obstacles by a multi-joint, redundant limb: two synergies within one movement

We investigated survival of patients with out-of-hospital cardiac arrest in Ljubljana according to the 'Utstein' style. Ljubljana consists of urban, suburban and semi-rural communities which encompass an area of 1615 km2 with 397306 residents. The area is served by a single response emergency medical system and local family practitioners. Between January 1, 1995 and December 31, 1997 cardiac arrest was confirmed in 966 patients. Cardiopulmonary resuscitation was attempted in 454 patients (47%). Collapse of presumed cardiac etiology (337 patients) was either bystander-witnessed (89%), un-witnessed (9%) or EMS personnel-witnessed (2%). Asystole was documented in 55%, ventricular fibrillation or tachycardia in 36% and other non-perfusing rhythms in 9% of these patients. Lay-bystander basic life support was performed in 19%. Nineteen patients (5.6%) survived to hospital discharge and 12 of them were independent in daily life. The survival of subgroups with bystanders-witnessed collapse and bystanders-witnessed ventricular fibrillation was 6.4 and 13%, respectively. Collapse of non-cardiac etiology (117 patients) was preceded by either respiratory failure (41), politrauma (22), circulatory shock (19), cerebrovascular incident (ten), intoxication (nine), strangulation (seven), electrocution (five) or drowning (four patients). Only five patients (4.2%) survived to hospital discharge. Hospital treatment of patients after successful initial cardiopulmonary resuscitation was associated with high mortality and required considerable resources.     

Influence of comorbidity on the outcome of patients treated for out-of-hospital ventricular fibrillation

BACKGROUND: A number of factors have previously been shown to be predictive of survival from out-of-hospital ventricular fibrillation. These include witnessed collapse, prompt initiation of cardiopulmonary resuscitation, early application of defibrillation, and younger age. Arrests occurring away from home are also associated with improved survival. Additionally, hospital mortality after successful resuscitation has been related to a history of congestive heart failure as well as to some of the factors noted above. An association of prearrest comorbidity with outcome has not been systematically evaluated. METHODS AND RESULTS: We define here a comorbidity index, which is constructed from histories of chronic conditions as well as a number of recent symptoms in 282 victims of out-of-hospital VF. This indicator of comorbidity is strongly associated with outcome (P = .004). However, when analyzing a comprehensive set of predictors of survival after out-of-hospital ventricular fibrillation, including the index of comorbidity, we could identify overall only about one fourth of the variation that one might hope to account for. CONCLUSIONS: Comorbidity appears to be an important (but usually overlooked) predictor of survival from out-of-hospital ventricular fibrillation. However, most of the statistical variability in predicting survival remains unexplained when we consider comorbidity in conjunction with previously identified predictors of survival.     

The role of MRI of the knee

The purpose of this investigation was to determine factors associated with survival from out-of-hospital cardiac arrest, including effects of 911 Emergency Medical Services telephone access and the age of patient. Subjects included 1,753 prehospital cardiac arrest patients in Iowa. Patient survival status and other variables were compared for patients with access to a 911 service with those who did not, and for different age categories, using univariate associations and multivariate logistic regression analysis. The presence of 911 telephone access was significantly associated with survival from out-of-hospital cardiac arrest (9.18% versus 5.35% survival for 911 versus no 911 groups, respectively). This association was partially the result of the significant association of 911 with decreased time from collapse to call for help, decreased time to cardiopulmonary resuscitation (CPR), and decreased time to first shock (if in ventricular fibrillation [VF]). Younger age was significantly associated with survival in univariate analyses (8.94% versus 6.26% survival for younger versus older age groups, respectively), but this was not an independent association, which is indicated by the lack of significance of age in the multivariate model.     

A 10 year follow up of parenteral gold therapy in patients with rheumatoid arthritis

The objective of this study was the assessment of out-of-hospital cardiac arrest and the definition of possible predictive factors for final hospital discharge. Out of a database of 89,557 consecutive missions of the Vienna emergency medical system (EMS) during 1990, there were 623 missions due to a collapse of non-traumatic origin: in 374 cases (60.0%) the patients were declared dead without further attempts at resuscitation. The remaining 249 patients were analysed for predictive factors at site. Survival to hospital admission: 109 patients survived to hospital admission (43.7%); bystander support had a small impact (P < 0.05) on survival to hospital arrival whereas age and gender had no predictive power. Most patients with ventricular tachycardia/fibrillation (VT/VF) survived primarily (69 of 117, i.e. 59.0%). Survival to hospital discharge: 27 patients were discharged from hospital care (10.8%). ECG findings on arrival of the EMS physician at the site proved to be the only powerful predictor for survival: 24 of 117 patients with VT/VF survived compared with only one of 81 with primary asystole, two of 39 with severe bradycardia, and no patient with electromechanical dissociation.     

Survival after cardiac arrest outside hospital over a 12-year period in Gothenburg

BACKGROUND: A two-tiered ambulance system with a mobile coronary care unit and standard ambulance has operated in Gothenburg (population 434,000) since 1980. Mass education in cardiopulmonary resuscitation (CPR) commenced in 1985 and in 1988 semiautomatic defibrillators were introduced. Aim: To describe early and late survival after cardiac arrest outside hospital over a 12-year period. Target population: All patients with prehospital cardiac arrest in Gothenburg reached by mobile coronary care unit or standard ambulance between 1980 and 1992. RESULTS: The number of patients with cardiac arrest remained fairly steady over time. Among patients with witnessed ventricular fibrillation, the time to defibrillation decreased over time. The proportion of patients in whom bystander initiated CPR was increased only moderately over time. The proportion of patients given medication such as lignocaine and adrenaline successively increased. The number of patients with cardiac arrest who were discharged from hospital per year remained steady between 1981 and 1990 (20 per year), but increased during 1991 and 1992 to 41 and 31 respectively. CONCLUSIONS: Improvements in the emergency medical service in Gothenburg over a 12-year period have lead to: (1) a shortened delay time between cardiac arrest and first defibrillation and (2) an improved survival of patients with cardiac arrest outside hospital probably explained by this shortened delay time.     

Effects of intra-aortic balloon occlusion on hemodynamics during, and survival after cardiopulmonary resuscitation in dogs

OBJECTIVE: To evaluate the effect of balloon occlusion of the proximal descending aorta during cardiopulmonary resuscitation (CPR) on hemodynamics, restoration of spontaneous circulation, and 24-hr survival. DESIGN: Prospective, randomized, controlled trial. SETTING: Experimental laboratory in a university hospital. SUBJECTS: Eighteen anesthetized dogs. INTERVENTIONS; Catheters were placed for hemodynamic and blood gas monitoring. An aortic balloon catheter was placed with its tip just distal to the left subclavian artery. After 10 mins of ventricular fibrillation without CPR, 3 mins of Basic Life Support (chest compressions and ventilation with 100% oxygen) was followed by up to 30 mins of Advanced Cardiac Life Support with canine drug dosages. In the treatment group (n = 8), the intra-aortic balloon was inflated when Advanced Cardiac Life Support started and not deflated until shortly after restoration of spontaneous circulation. The control animals (n = 10) were treated with an identical resuscitation but without intra-aortic balloon occlusion. MEASUREMENTS AND MAIN RESULTS: In the treatment group, coronary perfusion pressure was greater during Advanced Cardiac Life Support (p = .026). Restoration of spontaneous circulation was more frequent (7/8 dogs) as compared with the control group (3/10 dogs) (p = .025). There was a trend toward greater 24-hr survival in the treatment group (5/8 dogs) than in the control group (3/10 dogs). CONCLUSIONS: Balloon occlusion of the proximal descending aorta during experimental CPR improves restoration of spontaneous circulation. Further laboratory and human studies are needed to determine the clinical efficacy of this technique.     

Prevalence of lysosomal storage disorders

BACKGROUND: Outcome of cardiopulmonary resuscitation (CPR) can be poor, in terms of life expectancy and quality of life. OBJECTIVES: To determine the impact of patient characteristics before, during, and after CPR on these outcomes, and to compare results of the quality-of-life assessment with published studies. METHODS: In a cohort study, we assessed by formal instruments the quality of life, cognitive functioning, depression, and level of dependence of survivors after inhospital CPR. Follow-up was at least 3 months after discharge from the hospital (tertiary care center). RESULTS: Of 827 resuscitated patients, 12% (n = 101) survived to follow-up. Of the survivors, 89% participated in the study. Most survivors were independent in daily life (75%), 17% were cognitively impaired, and 16% had depressive symptoms. Multivariate regression analysis showed that quality of life and cognitive function were determined by 2 factors known before CPR-the reason for admission and age. Factors during and after resuscitation, such as prolonged cardiac arrest and coma, did not significantly determine the quality of life or cognitive functioning of survivors. The quality of life of our CPR survivors was worse compared with a reference group of elderly individuals, but better than that of a reference group of patients with stroke. The quality of life did not importantly differ between the compared studies of CPR survivors. CONCLUSIONS: Cardiopulmonary resuscitation is frequently unsuccessful, but if survival is achieved, a relatively good quality of life can be expected. Quality of life after CPR is mostly determined by factors known before CPR. These findings may be helpful in informing patients about the outcomes of CPR.     

Postresuscitation left ventricular systolic and diastolic dysfunction. Treatment with dobutamine

BACKGROUND: Global left ventricular dysfunction after successful resuscitation is well documented and appears to be a major contributing factor in limiting long-term survival after initial recovery from out-of-hospital sudden cardiac death. Treatment of such postresuscitation myocardial dysfunction has not been examined previously. METHODS AND RESULTS: Systolic and diastolic parameters of left ventricular function were measured in 27 swine before and after successful resuscitation from prolonged ventricular fibrillation cardiac arrest. Dobutamine infusions (10 micrograms.kg-1.min-1 in 14 animals or 5 micrograms.kg-1.min-1 in 5 animals) begun 15 minutes after resuscitation were compared with controls receiving no treatment (8 animals). The marked deterioration in systolic and diastolic left ventricular function seen in the control group after resuscitation was ameliorated in the dobutamine-treated animals. Left ventricular ejection fraction fell from a prearrest 58 +/- 3% to 25 +/- 3% at 5 hours after resuscitation in the control group but remained unchanged in the dobutamine (10 micrograms.kg-1.min-1) group (52 +/- 1% prearrest and 55 +/- 3% at 5 hours after resuscitation). Measurement of the constant of isovolumic relaxation of the left ventricle (tau) demonstrated a similar benefit of the dobutamine infusion for overcoming postresuscitation diastolic dysfunction. The tau rose in the controls from 28 +/- 1 milliseconds (ms) prearrest to 41 +/- 3 ms at 5 hours after resuscitation whereas it remained constant in the dobutamine-treated animals (31 +/- 1 ms prearrest and 31 +/- 5 ms at 5 hours after resuscitation). CONCLUSIONS: Dobutamine begun within 15 minutes of successful resuscitation can successfully overcome the global systolic and diastolic left ventricular dysfunction resulting from prolonged cardiac arrest and cardiopulmonary resuscitation.     

Future directions for resuscitation research. III. External cardiopulmonary resuscitation advanced life support

This discussion about advanced cardiac life support (ACLS) reflects disappointment with the over 50% of out-of-hospital cardiopulmonary resuscitation (CPR) attempts that fail to achieve restoration of spontaneous circulation (ROSC). Hospital discharge rates are equally poor for in-hospital CPR attempts outside special care units. Early bystander CPR and early defibrillation (manual, semi-automatic or automatic) are the most effective methods for achieving ROSC from ventricular fibrillation (VF). Automated external defibrillation (AED), which is effective in the hands of first responders in the out-of-hospital setting, should also be used and evaluated in hospitals, inside and outside of special care units. The first countershock is most important. Biphasic waveforms seem to have advantages over monophasic ones. Tracheal intubation has obvious efficacy when the airway is threatened. Scientific documentation of specific types, doses, and timing of drug treatments (epinephrine, bicarbonate, lidocaine, bretylium) are weak. Clinical trials have failed so far to document anything statistically but a breakthrough effect. Interactions between catecholamines and buffers need further exploration. A major cause of unsuccessful attempts at ROSC is the underlying disease, which present ACLS guidelines do not consider adequately. Early thrombolysis and early coronary revascularization procedures should also be considered for selected victims of sudden cardiac death. Emergency cardiopulmonary bypass (CPB) could be a breakthrough measure, but cannot be initiated rapidly enough in the field due to technical limitations. Open-chest CPR by ambulance physicians deserves further trials. In searches for causes of VF, neurocardiology gives clues for new directions. Fibrillation and defibrillation thresholds are influenced by the peripheral sympathetic and parasympathetic nervous systems and impulses from the frontal cerebral cortex. CPR for cardiac arrest of the mother in advanced pregnancy requires modifications and outcome data. Until more recognizable critical factors for ROSC are identified, titrated sequencing of ACLS measures, based on physiologic rationale and sound judgement, rather than rigid standards, gives the best chance for achieving survival with good cerebral function.     

Possible reasons for the variability of human responses to IAC-CPR

OBJECTIVE: To propose reasons for the variability of the hemodynamic responses and survival data observed when interposed abdominal compression cardiopulmonary resuscitation (IAC-CPR) is performed on humans in cardiac arrest. METHODS: Critical content review of all studies performed in the United States examining IAC-CPR in humans and of selected animal studies addressing hemodynamic mechanisms of CPR. Articles in the English language dealing with human IAC-CPR studies from 1970-1993 were retrieved using the MEDLINE database of the National Library of Medicine. RESULTS: IAC-CPR does not consistently improve coronary perfusion pressure (CPP) over standard CPR in humans and is capable of decreasing as well as increasing CPP. This variability does not seem dependent on the manner in which abdominal compressions are performed. Because of the limited response to standard CPR, significant increases in return of spontaneous circulation would be expected with IAC-CPR if a large percentage of patients were to have favorable increases in CPP. However, other patients may be adversely affected by decreases in CPP during IAC-CPR, with unsuccessful resuscitation of those individuals. Return of spontaneous circulation also may be enhanced using IAC-CPR due to other factors reflected in the initial arrest rhythm and in arrest-population demographics. CONCLUSION: IAC-CPR should not be recommended for routine use until the mechanism of its beneficial effects is known and until those patients who are likely to benefit from the technique can be better identified.