Can successful treatment of cardiac arrest be a performance indicator for hospitals?

BACKGROUND: Although resuscitation from cardiac arrest prevents more deaths from acute myocardial infarction (MI) than any other treatment, results have not been audited widely nor performance standards proposed. METHODS: The Myocardial Infarction National Audit Project (MINAP) uses electronic transmission of a 53-item dataset to a central cardiac audit database (CCAD). From October 2000 to August 2002, transmission by 218 hospitals of data from 55,906 cases of MI with 4934 attempted resuscitations from a first arrest, allowed for examination of factors determining survival, and for possible future measurement of success in resuscitation as a performance indicator. We investigated two possible indicators: (i) numbers of survivors from arrest in ventricular fibrillation or pulseless ventricular tachycardia (VF/VT) per 1000 cases of MI; and (ii) observed/expected (O/E) ratios for survival taking all VF/VT arrests rather than MI as the denominator, and adjusting for differing age structures and admission delays among individual hospitals. FINDINGS: Of the 4934 reported patients suffering a first arrest, 1778 (36%) survived to be discharged from hospital. The presenting rhythm was VF/VT in 2321 (47%) patients of whom 1461 (63%) survived. Survival for all 218 hospitals together had the relatively small 95% confidence limits of 26 (25-27) survivors from VF/VT per 1000 MI. However, the small numbers from individual hospitals made it impossible in most cases, whichever of the two indicators was used, to separate quality of performance and completeness of reporting from the factor of chance. INTERPRETATION: Audit of success in resuscitation is essential if performance in the treatment of MI is to be assessed. However, the relatively small numbers of arrests occurring in individual hospitals means that if year on year improvements are to be documented, audit must be carried out among groups of hospitals or on a national scale.     

Can transvaginal fetal biometry be considered a useful tool for early detection of skeletal dysplasias in high-risk patients?

OBJECTIVE: To evaluate the possibility of an early diagnosis of skeletal dysplasias in high-risk patients. METHODS: A total of 149 consecutive, uncomplicated singleton pregnancies at 9-13 weeks' amenorrhea, with certain menstrual history and regular cycles, were investigated with transvaginal ultrasound to establish the relationship between femur length and menstrual age, biparietal diameter and crown-rump length, using a polynomial regression model. A further eight patients with previous skeletal dysplasias in a total of 13 pregnancies were evaluated with serial examinations every 2 weeks from 10-11 weeks. RESULTS: A significant correlation between femur length and crown-rump length and biparietal diameter was found, whereas none was observed between femur length and menstrual age. Of the five cases with skeletal dysplasias, only two (one with recurrent osteogenesis imperfecta and one with recurrent achondrogenesis) were diagnosed in the first trimester. CONCLUSIONS: An early evaluation of fetal morphology in conjunction with the use of biometric charts of femur length against crown-rump length and femur length against biparietal diameter may be crucial for early diagnosis of severe skeletal dysplasias. By contrast, in less severe cases, biometric evaluation appears to be of no value for diagnosis.     

The problem with and benefit of ventilations: should our approach be the same in cardiac and respiratory arrest?

PURPOSE OF REVIEW: Recent advances in cardiopulmonary resuscitation have led to greater understanding of cardio-cerebral-pulmonary interactions during the process. The purpose of this discussion is to update the physiologic understanding of these interactions during cardiopulmonary resuscitation, review the detrimental and beneficial effects of ventilation, and identify implications for clinical practice. RECENT FINDINGS: There is an inversely proportional relationship between mean intrathoracic pressure, coronary perfusion pressure, and survival from cardiac arrest. Increased ventilation rates and increased ventilation duration impede venous blood return to the heart, decreasing hemodynamics and coronary perfusion pressure during cardiopulmonary resuscitation. It has also been shown that there is a direct and immediate transfer of the increase in intrathoracic pressure to the cranial cavity with each positive pressure ventilation, also reducing cerebral perfusion pressure. The reduced amount of blood flowing through the pulmonary bed during cardiopulmonary resuscitation tends to be overventilated, compromising hemodynamics to both the heart and brain and resulting in ventilation/perfusion mismatch. SUMMARY: The fundamental hemodynamic principle of intrathoracic pressure defines cardio-cerebral-pulmonary interactions during cardiopulmonary resuscitation. Further research is essential to optimize these interactions during treatment of profound shock.     

Hypothermia and neurologic outcome in patients following cardiac arrest: should we be hot to cool off our patients?

Hypothermia as a protectant of neurologic function in the treatment of cardiac arrest patients, although not a new concept, is now supported by two recent randomized, prospective clinical trials. The basic science research in support of the effects of hypothermia at the cellular and animal levels is extensive. The process of cooling for cerebral protection holds potential promise for human resuscitation efforts in multiple realms. It appears that, at least, those patients who suffer a witnessed cardiac arrest with ventricular fibrillation and early restoration of spontaneous circulation, such as those who were included in the European and Australian trials (discussed here), should be considered for hypothermic therapy.     

Postresuscitation disease after cardiac arrest: a sepsis-like syndrome?

PURPOSE OF REVIEW: Despite advances in cardiac arrest resuscitation, neurologic impairments and other organ dysfunctions cause considerable mortality and morbidity after restoration of spontaneous cardiac activity. The mechanisms underlying this postresuscitation disease probably involve a whole-body ischemia and reperfusion syndrome that triggers a systemic inflammatory response. RECENT FINDINGS: Postresuscitation disease is characterized by high levels of circulating cytokines and adhesion molecules, the presence of plasma endotoxin, and dysregulated leukocyte production of cytokines: a profile similar to that seen in severe sepsis. Transient myocardial dysfunction can occur after resuscitation, mainly as a result of myocardial stunning. However, early successful angioplasty is independently associated with better outcomes after cardiac arrest associated with myocardial infarction. Coagulation abnormalities occur consistently after successful resuscitation, and their severity is associated with mortality. For example, plasma protein C and S activities after successful resuscitation are lower in nonsurvivors than in survivors. Low baseline cortisol levels may be associated with an increased risk of fatal early refractory shock after cardiac arrest, suggesting adrenal dysfunction in these patients. SUMMARY: Postresuscitation abnormalities after cardiac arrest mimic the immunologic and coagulation disorders observed in severe sepsis. This suggests that therapeutic approaches used recently with success in severe sepsis should be investigated in patients successfully resuscitated after cardiac arrest.     

Surviving out of hospital cardiac arrest at home: a postcode lottery?

Methods: Retrospective cohort study over 10 years, 1 December 1991 to 1 August 2001. Outcome and demographic data were obtained for 1956 OHCAs occurring at home, in the Lothians region, from the Heartstart Scotland database. Survival rates to hospital admission and discharge were examined by postcode district.

Results: Certain postcode areas were served by quicker response times and shorter journeys. The survival to admission rate was greater in those areas where the median response time was <10 minutes (13.5% versus 8.1%, p<0.05). There was greater survival to discharge in these areas but not significantly so (4.1% versus 3.2%, p = 0.42). Survival to admission was more likely in areas where the median distance travelled was <four miles (13.3% versus 9.7%, p<0.05) but not survival to discharge (4.0% versus 3.7%, p = 0.72). A close correlation between distance travelled and response time was shown (Pearson = 0.93, p<0.01), likewise between distance travelled and survival to admission (Spearman = –0.87, p<0.01). Certain areas, particularly those at greater geographical distance from ambulance dispatch points, were found to be associated with significantly lower survival to admission rates.

Conclusions: Survival to admission from OHCA is strongly influenced by response time and distance travelled to the scene. The geographical location of an arrest can potentially influence survival to admission. Measures should be taken to strategically position ambulance dispatch points and to task the nearest geographically available vehicle to attend an OHCA.

     

In-hospital cardiac arrest: Is outcome related to the time of arrest?

BACKGROUND: Whether outcome from in-hospital cardiopulmonary resuscitation (CPR) is poorer when it occurs during the night remains controversial. This study examined the relationship between CPR during the various hospital shifts and survival to discharge. METHODS: CPR attempts occurring in a tertiary hospital with a dedicated, certified resuscitation team were recorded prospectively (Utstein template guidelines) over 24 months. Medical records and patient characteristics were retrieved from patient admission files. RESULTS: Included were 174 in-hospital cardiac arrests; 43%, 32% and 25% in morning evening and night shifts, respectively. Shift populations were comparable in demographic and treatment related variables. Asystole (p < 0.01) and unwitnessed arrests (p = 0.05) were more common during the night. Survival to discharge was poorer following night shift CPR than following morning and evening shift CPR (p = 0.04). When asystole (being synonymous with death) was excluded from the analysis, the odds of survival to discharge was not higher for witnessed compared to unwitnessed arrest but was 4.9 times higher if the cardiac arrest did not occur during the night shift (p = 0.05, logistic regression). The relative risk of eventual in-hospital death for patients with return of spontaneous circulation (ROSC) following night shift resuscitation was 1.9 that of those with ROSC following morning or evening resuscitation (Cox regression). CONCLUSIONS: Although unwitnessed arrest is more prevalent during night shift, resuscitation during this shift is associated with poorer outcomes independently of witnessed status. Further research is required into the causes for the increased mortality observed after night shift resuscitation.     

Cerebral vasoconstriction in comatose patients resuscitated from a cardiac arrest?

Objective To determine the role of cerebral vasoconstriction in the delayed hypoperfusion phase in comatose patients after cardiac arrest.Design Prospective study.Setting Medical intensive care unit in a university hospital.Patients 10 comatose patients (Glasgow Coma Score 6) successfully resuscitated from a cardiac arrest occurring outside the hospital.Measurements We measured the pulsatility index (PI) and mean blood flow velocity (MFV) of the middle cerebral artery, the cerebral oxygen extraction ratio and jugular bulb levels of endothelin, nitrate, and cGMP during the first 24 h after cardiac arrest.Results The PI decreased significantly from 1.86±1.02 to 1.05±0.22 (p=0.03). The MFV increased significantly from 29±10 to 62±25 cm/s (p=0.003). Cerebral oxygen extraction ratio decreased also from 0.39±0.13 to 0.24±0.11 (p=0.015). Endothelin levels were high but did not change during the study period. Nitrate levels varied widely and showed a slight but significant decrease from 37.1 mol/l (median; 25th–75th percentiles: 26.8–61.6) to 31.3 mol/l (22.1–39.6) (p=0.04). Cyclic guanosine monophosphate levels increased significantly from 2.95 nmol/l (median; 25th–75th percentiles: 2.48–5.43) to 7.5 nmol/l (6.2–14.0) (p=0.02).Conclusions We found evidence of increased cerebrovascular resistance during the first 24 h after cardiac arrest with persistent high endothelin levels, gradually decreasing nitrate levels, and gradually increasing cGMP levels. This suggests that active cerebral vasoconstriction due to an imbalance between local vasodilators and vasoconstrictors plays a role in the delayed hypoperfusion phase.