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.     

Usefulness of central venous oxygen saturation monitoring during cardiopulmonary resuscitation. A comparative case study with end-tidal carbon dioxide monitoring

The usefulness of continuous monitoring of central venous oxygen saturation (ScvO2) in comparison with the capnogram during cardiopulmonary resuscitation (CPR) was demonstrated in a cardiac arrest patient. ScvO2 and end-tidal carbon dioxide (ETCO2) decreased following cessation of chest compression or increased during recovery of systemic circulation. During the complete stasis of systemic circulation, when defibrillation was done, ScvO2 did not change, while ETCO2 gradually decreased. However the larger decrease in ScvO2 temporally occurred when chest compression was resumed. And also the ScvO2 monitoring had great advantage to detecting peripheral tissue oxygenation. ScvO2 seems to be no less accurate and reliable monitoring than the capnogram during CPR procedures. Since the capnogram is non-invasively and easily used in cardiac arrest patients, ScvO2 monitoring combined with the capnogram is a more preferable method for assessing the efficacy of ongoing CPR.     

Antiproliferative therapy with 5-fluorouracil in erbium:YAG laser sclerostomy ab externo

In the United States debate continues about the necessity of ventilation during CPR because of fear of contracting infectious diseases. Three questions will be considered in this article. First, is ventilation necessary for the treatment of cardiac arrest? Second, is mouth-to-mouth ventilation any better than no ventilation at all? Third, are other techniques of ventilation as effective or more effective than mouth-to-mouth ventilation during basic life support CPR? Although research is still inconclusive with regard to the need for ventilation during CPR, recent findings have clarified the effect of ventilation during low blood flow states and how ventilation influences resuscitation. Ventilation affects oxygenation, carbon dioxide elimination, and pH during times of low rates of blood flow. Ventilation may be unnecessary during the first few minutes of CPR. Under conditions of prolonged, untreated cardiac arrest, ventilation during CPR affects return of spontaneous circulation. Isolated hypoxemia and hypercarbia independently have adverse effects on survival of cardiac arrest. Because ventilation with exhaled gas contains as much as 4% CO2 and less oxygen than air, it may have adverse effects during CPR. Spontaneous gasping may provide sufficient ventilation during CPR. Chest compression alone provides some pulmonary ventilation and gas exchange. Active chest compression-decompression may improve gas exchange better than does standard chest compression. Other forms of manual ventilation may also have a role in CPR.     

The 5-HT1A and 5-HT2A/2C receptor antagonists WAY-100635 and ritanserin do not attenuate D-fenfluramine-induced fos expression in the brain

In a prospective randomised study we investigated end-tidal carbon dioxide levels during standard versus active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) assuming that the end-tital carbon dioxide reflects cardiac output during resuscitation. In each group 60 patients with out-of-hospital cardiac arrest were treated either with the standard or the ACD method. End-tidal CO2 (p(et)CO2, mmHg) was assessed with a side-stream capnometer following intubation and then every 2 min up to 10 min or restoration of spontaneous circulation (ROSC). There was no difference in p(et)CO2 between both patient groups. However, CO2 was significantly higher in patients who were admitted to hospital as compared to patients declared dead at the scene. All of the admitted patients had a p(et)CO2 of at least 15 mmHg no later than 2 min following intubation, none of the dead patients ever exceeded 15.5 mmHg. From these data we conclude that capnometry adds valuable information to the estimation of a patient's prognosis in the field (threshold, 15 mmHg), but we could not detect any difference in p(et)CO2 between ACD and standard CPR.     

Striatopallidal and thalamic dystonia. A magnetic resonance imaging anatomoclinical study

The effects of manual and a new mechanical chest compression device (Heartsaver 2000) during prolonged CPR with respect to haemodynamics and outcome were tested in a prospective, randomized, controlled experimental trial during ventricular fibrillation in 12 dogs of 9-13 kg body weight after 1 min of cardiac arrest. During the first 10 min of CPR the dogs were resuscitated according to the Basic Life Support (BLS) algorithm, followed by 20 min of Advanced Life Support (ALS) algorithm. After 30 min of CPR both manual and mechanical CPR groups were resuscitated following a standardized ALS protocol. During CPR, coronary perfusion pressure and end tidal CO2 were greater with mechanical CPR. All animals were successfully resuscitated and neurological deficit scores were not different. The CPR trauma score was less in the mechanical group. Mechanical external chest compression provided better haemodynamics than the manual technique, though outcome did not differ. Both optimally performed manual and mechanical techniques produce flow sufficient to maintain organ viability for 30 min of CPR after a 1 min arrest interval.     

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.     

Ventricular arrhythmias in the elderly

Sudden cardiac death is one of the leading causes of death and a major public health problem that particularly affects the elderly. Sudden cardiac death may be a terminal event after a prolonged debilitating and painful illness, or it may occur following many years of symptoms related to a cardiac disorder; however, in many elderly persons, the cardiac arrest may be the first manifestation of cardiac disease in a supposedly healthy and physically active person. Whether cardiopulmonary resuscitation should be performed in elderly patients who sustain cardiac arrest is a significant issue confronting the medical profession and the general public. Several questions must be answered when evaluating the decision of whether or not to perform cardiopulmonary resuscitation on an elderly patient.     

Interaction of the Na(+)-Ca2+ exchanger with small molecules on cell Ca2+ signaling

BACKGROUND: Evaluation of outcome after CPR in severe hypothermic patients. DESIGN: Perspective study from October 1995 to April 1996. SETTING: First aid team of Italian Red Cross, Busto Arsizio (Varese), Italy. METHODS: A population of 22 patients in cardiac arrest in which CPR was performed immediately after rescue team's arrival is studied. ECG, core temperature, SpO2 and MAP were monitored whereas vital parameters were present during Basic Life Support. Outcome after CPR was evaluated with GOS scale. RESULTS: It has been observed that severe hypothermia and time of cardiac arrest impact on the clinical outcome after CPR. The high mortality rate after CPR with BLS standard is worsened by a core temperature < or = 33 degrees C. CONCLUSIONS: Severe hypothermia seems to have a dangerous effect upon outcome after cardiopulmonary resuscitation; heating systems for body temperature could prevent this situation improving CPR results.     

Substrate specificity of human prolyl-4-hydroxylase

BACKGROUND: The mechanism responsible for the forward blood flow associated with external chest compression is still controversial. Evidence for both blood flow caused by direct cardiac compression and blood flow generated by a general increase in intrathoracic pressure has been found in experimental as well as clinical studies. No data are available concerning the mechanism causing forward blood flow in hypothermic patients undergoing cardiopulmonary resuscitation. Therefore, echocardiographic findings during external chest compression in seven hypothermic arrest victims are reported. METHODS: All transesophageal echocardiographic studies performed at the Anaesthesia department between 1994 and 1997 were reviewed and seven hypothermic patients with transesophageal echocardiography performed during cardiopulmonary resuscitation were identified. RESULTS: An open mitral valve or a circumferential reduction in aortic diameter during the compression phase was found in four of seven patients, indicating that primarily an increase in intrathoracic pressure (thoracic pump mechanism) generated forward blood flow. In three patients, mitral valve closure during external chest compression indicated that direct cardiac compression (cardiac pump mechanism) contributed to forward blood flow. Two patients studied during active compression-decompression cardiopulmonary resuscitation demonstrated enhanced right ventricular filling and aortic valve opening during active decompression of the thorax. CONCLUSIONS: In contrast to normothermic arrest victims, an open mitral valve during external chest compression is a common finding during hypothermia, indicating that thoracic pump mechanism is important for forward blood flow during cardiopulmonary resuscitation in hypothermic arrest victims. Aortic valve opening in two hypothermic arrest victims suggests forward blood flow also during active decompression of the thorax with the Cardiopump.     

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.     

Flow cytometry in cervical adenocarcinoma. Correlating DNA content analysis with the clinical picture

A case is presented in which prolonged resuscitation and rewarming was performed following post-rescue cardiopulmonary arrest in severe immersion hypothermia. The rescue and resuscitation techniques necessary to optimise outcome in such cases are described.     

Future directions for resuscitation research. IV. Innovative advanced life support pharmacology

The topics discussed in this session include a partial review of laboratory and clinical studies examining the effects of adrenergic agonists on restoration of spontaneous circulation after cardiac arrest, the effects of varying doses of epinephrine, and the effects of novel vasopressors, buffer agents (NaHCO3, THAM, 'Carbicarb') and anti-arrhythmics (lidocaine, bretylium, amiodarone) in refractory ventricular fibrillation. Novel therapeutic approaches include titrating electric countershocks against electrocardiographic power spectra and of preceding the first countershocks with single or multiple drug treatments. These approaches need to be investigated further in controlled animal and patient studies. Epidemiologic data from randomized clinical outcome studies can give clues, but cannot document pharmacologic mechanisms in the dynamically changing events during attempts to achieve restoration of spontaneous circulation from prolonged cardiac arrest. Also, rapid drug administration by the intraosseous route was compared with intratracheal and intravenous (i.v.) drug administration. Many studies on the above treatments have yielded conflicting results because of differences between healthy hearts of animals and sick hearts of patients, differences in arrest (no-flow) times and cardiopulmonary resuscitation (CPR) (low-flow) times, different pharmacokinetics, different dose/response requirements, and different timing of drug administration during low-flow CPR versus during spontaneous circulation. The need to stabilize normotension and prevent rearrest by titrated novel drug administration, once spontaneous circulation has been restored, requires research. Most of the above topics require some re-evaluation in clinically realistic animal models and in cardiac arrest patients, especially by titration of old and new drug treatments against variables that can be monitored continuously during resuscitation.     

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.     

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.     

Dominant lethal study of alpha-asarone in male mice

The crucial factor deciding the success of cardiopulmonary resuscitation is a sufficient oxygen supply. At about 4 min after cardiac arrest, cerebral death results because of hypoxia, and cardiopulmonary resuscitation has to be started regardless of the pathogenesis of the cardiac arrest. The purpose of the study was to assess the application of guidelines for cardiopulmonary resuscitation by participants at a dental surgery congress (n = 96) and to evaluate previous knowledge in cardiopulmonary resuscitation and knowledge after instruction. The present study was based on the standards and guidelines for cardiopulmonary resuscitation issued by the American Heart Association. The group was divided into four groups of doctors experienced or inexperienced in clinical emergencies or with dummies. For the study the Skillmeter-ResusciAnne (Laerdal, Stavanger, Norway) was used, which has automatic data recording. After analysis of the individual errors, the success of new instruction was assessed. Good previous knowledge was registered, particularly with respect to checking respiration and hyperextension of the head (67.7%), primary insufflation (93.8%), closed-chest cardiac massage (99%) and correct compression rate (68.4%). The participants demonstrated post-instruction improvement in all subdivisions except in the group without practice on dummies (primary insufflation: from 94.4 to 88.9%; correct order of checking consciousness and respiration, primary insufflation, the carotid pulse and closed-chest cardiac massage: from 22.2 to 5.6%). Good results with marked improvements in the second passage were achieved in checking consciousness and the carotid pulse, closed-chest cardiac massage and correct implementation of compression. The participants were, however, found to be in need of further education and training in diagnostics and certain cardiopulmonary resuscitation measures. Knowledge should be improved concerning recognition of the emergency (42.7%), checking the carotid pulse (22.9%), the correct order of primary insufflation and closed-chest cardiac massage (9.4%), correct implementation of compression (21.8%) and ventilation (36.4%), and the correct ratio of compression and ventilation (21.9%). Regular courses should be targeted at these specific aspects.     

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.     

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.     

Effect of selective aortic arch perfusion on median frequency and peak amplitude of ventricular fibrillation in a canine model

STUDY OBJECTIVE: To determine whether the computer-derived measures of median frequency or peak amplitude of ventricular fibrillation (VF), obtained by fast Fourier transform of the VF waveform, change during selective aortic arch perfusion in a canine model of cardiac arrest. METHODS: Eight mongrel dogs (including 4 control animals) were sedated, intubated, catheterized, and instrumented to record the electrocardiogram (digitally at 100 Hz, filtered with a finite impulse response filter at 2 Hz), right atrial pressure, and aortic pressure during resuscitation in a model of VF-induced cardiac arrest. After 10 minutes of VF-induced arrest, cardiopulmonary resuscitation (CPR) with a mechanical chest compression device was initiated. Beginning 2 minutes later, the 4 study animals received, every 2 minutes, 45 seconds of selective aortic arch perfusion (SAAP) with autologous blood infusions under high pressure. Defibrillation was attempted after 3 minutes of CPR and every minute thereafter. Both study and control groups received standard-dose epinephrine (.01 mg/kg) every 3 minutes by means of an intraaortic catheter. The median frequency, peak amplitude, and coronary perfusion pressure (CPP) during the 5-second period just before defibrillation were obtained with the use of computer algorithms. RESULTS: All SAAP animals and 1 control animal were resuscitated. Baseline measures of median frequency (8.4 +/- 1.5 versus 6.6 +/- 1.0 Hz) and peak amplitude (.18 +/- .05 versus .36 +/- .13 mV) were not different between the SAAP and control groups, respectively, at the start of CRP. SAAP infusion resulted in significant increases in the SAAP group compared with the control group: median frequency, 9.6 +/- .4 versus 7.3 +/- 1.4 Hz; peak amplitude, .74 +/- .21 versus .39 +/- .15 mV; and CPP, 40.5 +/- 7.1 versus 18.0 +/- 15.0 mm Hg, respectively. Median frequency correlated with CPP (r2 = .67). Peak amplitude did not correlate with CPP (r2 = .06). CONCLUSION: Median frequency and peak amplitude increase with SAAP during cardiac arrest in a canine model. This method of resuscitation was reliable in allowing restoration of a stable perfusing rhythm after defibrillation. Changes in measures of peak amplitude and median frequency may reflect interventions that enhance the likelihood of successful defibrillation and may thereby offer a noninvasive means of monitoring interventions during cardiac arrest.     

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.