Successful Restoration Of Spontaneous Circulation Research Articles

Edaravone Ameliorates Renal Warm Ischemia-Reperfusion Injury by Downregulating Endoplasmic Reticulum Stress in a Rat Resuscitation Model.

BackgroundThis study was conducted to explore whether the effect of edaravone (5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol3-one, EDR) can ameliorate renal warm ischemia-reperfusion injury (IRI) by modulating endoplasmic reticulum stress (ERS) and its downstream effector after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) in a rat model.MethodsThe rats (n=10) experienced anaesthesia and intubation followed by no CA inducement were defined as the Sham group. Transoesophageal alternating current stimulation was employed to establish 8 min of CA followed by conventional CPR for a resuscitation model. The rats with successful restoration of spontaneous circulation (ROSC) randomly received EDR (3 mg/kg, EDR group, n=10) or equal volume normal saline solution (the NS group, n=10). At 24 hr after ROSC, serum creatinine (SCR), blood urea nitrogen (BUN) levels, and cystatin-C (Cys-C) levels were determined and the protein level of glucose-regulated protein (GRP78), C/EBP homologous protein (CHOP), extracellular signal-regulated kinase (ERK), phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2), Bax/Bcl-2, and caspase-3 were detected by Western blot method.ResultsAt 24 hrs after ROSC, SCR, BUN and Cys-C were obviously increased and the proteins expression, including GRP78, CHOP and p-ERK1/2, cleaved-caspase 3 Bax/Bcl-2 ratio, were significantly upregulated in the NS group compared with the Sham group (p<0.05). The remarkable improvement of these adverse outcomes was observed in the EDR group (p<0.05).ConclusionIn conclusion, we found that EDR ameliorates renal warm IRI by downregulating ERS and its downstream effectors in a rat AKI model evoked by CA/CPR. These data may provide evidence for future therapeutic benefits of EDR against AKI induced by CA/CPR.

Successful Defibrillation of Four Hypothermic Patients with Witnessed Cardiac Arrest

Because of the limited evidence available, recommendations for defibrillation of hypothermic patients vary among published guidelines. To report successful defibrillation of four severely hypothermic patients with witnessed cardiac arrest. During a four-year period from 2014 to 2017, four of five hypothermic patients admitted to our institution with a history of sudden, unexpected ventricular fibrillation (core temperature: 24°C-27°C) were successfully defibrillated. Restoration of spontaneous circulation (ROSC) was possible after a single defibrillator shock (two patients) or during prolonged advanced life support cardiopulmonary resuscitation (two patients). Our patients and additional cases identified in the literature indicate that successful defibrillation is predominantly found in hypothermic patients with a core temperature above 24°C. Our data demonstrate that successful defibrillation and ROSC are possible in selected patients with severe accidental hypothermia and are perhaps more common than widely believed. These findings are of particular importance for mountain and wilderness rescue missions when transfer of an arrested patient to the nearest hospital providing extracorporeal rewarming is not possible. An automatic external defibrillator should be part of the medical equipment on any search or mountain rescue mission, in which the victim may have sustained accidental hypothermia.

Optimizing Patient Access During an Emergency While Using Intraoperative Computed Tomography

As minimally invasive spine surgery evolves, spine surgeons increasingly rely on advanced intraoperative computed tomography (iCT). iCT provides rapid acquisition of high-resolution images, reduces radiation exposure, improves surgical accuracy, and decreases operative time. However, all iCT systems currently available pose a patient safety risk as their physical space requirements limit patient access in the event of an emergency, particularly when patients are in the prone position. After a near-cardiac arrest at our institution during posterior cervical spine surgery, it was apparent that the presence of the iCT complicated the ability to rapidly reposition the patient in order to provide appropriate resuscitation. To ensure our ability to provide timely care during an emergency, we determined that a process which included all members of the operating room (OR) team was required. We held an initial planning meeting where a detailed plan-of-action was created, reviewed, and revised in response to feedback from all stakeholders. We then simulated a cardiac arrest to test our resuscitation plan with all members of the neurosurgery team. A mannequin was positioned prone on an OR table within the iCT, and a resuscitation plan was created. The team orchestrated the mock resuscitation, and the time of cardiac arrest in the prone position to supine repositioning required 110 seconds. The simulation was recorded for post-"code" performance review. Application of the protocol during an actual cardiac arrest was associated with successful restoration of spontaneous circulation and full recovery. The development and rehearsal of an emergency plan of action greatly facilitated the timely responsiveness of the neurosurgical OR team during a simulated cardiac arrest and was an effective way to identify and address key logistical issues regarding the use of an iCT system.

Non-occlusive mesenteric ischaemia in out of hospital cardiac arrest survivors.

Non-occlusive mesenteric ischaemia (NOMI) is characterised by hypoperfusion of the intestines without evidence of mechanical obstruction, potentially leading to extensive ischaemia and necrosis. Low cardiac output appears to be a major risk factor. Cardiopulmonary resuscitation aims at restoring blood flow after cardiac arrest. However, post restoration of spontaneous circulation, myocardial stunning limits immediate recovery of sufficient cardiac function. Since after successful cardiopulmonary resuscitation patients are often ventilated and sedated, NOMI might be underdiagnosed and potentially life-saving treatment delayed. A prospectively maintained multi-purpose cohort of out of hospital cardiac arrest survivors, who had successful restoration of spontaneous circulation, was used for this retrospective database analysis. Patients' charts were screened for clinical, radiological or pathological evidence of NOMI and clinical data were collected. Between 2000 and 2014, 1780 patients who were successfully resuscitated after out of hospital cardiac arrest were screened for NOMI. Twelve patients (0.68 %) suffered from NOMI and six of those died (50 %). Patients suffering from NOMI tended to have a longer duration until restoration of spontaneous circulation (27 vs. 20 min, p=0.128) and had significantly higher lactate (14 mmol/l vs. 8 mmol/l, p=0.002) and base deficit levels at admission (-17 vs. -10, p=0.012). Median leukocyte counts in NOMI patients peaked at the day of diagnosis. NOMI is a rare but life-threatening and potentially curable complication following successful cardiopulmonary resuscitation. Lactate and base deficit at admission could help to identify patients at risk for developing NOMI who might benefit from increased clinical attention.

Therapeutic effects of shenfu injection (参附注射液) on post-cardiac arrest syndrome

Survival rates after cardiac arrest have not changed substantially over the past 5 decades. Postcardiac arrest (CA) syndrome (PCAS) is the primary reason for the high mortality rate after successful restoration of spontaneous circulation (ROSC). Intravenous administration of Shenfu Injection (, SFI) may attenuate post-CA myocardial dysfunction and cerebral injury, inhibit systemic ischemia/reperfusion responses, and treat underlying diseases. In this article, we reviewed the therapeutic effects of SFI in PCAS. SFI might be useful in the treatment of PCAS, incorporating the multi-link and multi-target advantages of Chinese medicine into PCAS management. Further experimental and clinical research to verify the therapeutic effects of SFI in PCAS is required.

The Study Protocol for the LINC (LUCAS in Cardiac Arrest) Study: a study comparing conventional adult out-of-hospital cardiopulmonary resuscitation with a concept with mechanical chest compressions and simultaneous defibrillation

BackgroundThe LUCAS™ device delivers mechanical chest compressions that have been shown in experimental studies to improve perfusion pressures to the brain and heart as well as augmenting cerebral blood flow and end tidal CO2, compared with results from standard manual cardiopulmonary resuscitation (CPR). Two randomised pilot studies in out-of-hospital cardiac arrest patients have not shown improved outcome when compared with manual CPR. There remains evidence from small case series that the device can be potentially beneficial compared with manual chest compressions in specific situations. This multicentre study is designed to evaluate the efficacy and safety of mechanical chest compressions with the LUCAS™ device whilst allowing defibrillation during on-going CPR, and comparing the results with those of conventional resuscitation.Methods/designThis article describes the design and protocol of the LINC-study which is a randomised controlled multicentre study of 2500 out-of-hospital cardiac arrest patients. The study has been registered at ClinicalTrials.gov (http://clinicaltrials.gov/ct2/show/NCT00609778?term=LINC&rank=1).ResultsPrimary endpoint is four-hour survival after successful restoration of spontaneous circulation. The safety aspect is being evaluated by post mortem examinations in 300 patients that may reflect injuries from CPR.ConclusionThis large multicentre study will contribute to the evaluation of mechanical chest compression in CPR and specifically to the efficacy and safety of the LUCAS™ device when used in association with defibrillation during on-going CPR.

Effect of mechanical ventilation with different tidal volumes on pulmonary surfactant in dogs during cardiopulmonary resuscitation

Objective To observe the effects of mechanical ventilation with different tidal volumes (Vt) on the pulmonary surfactant in dogs during cardiopulmonary resuscitation (CPR) and discuss the strategy of mechanical ventilation for CPR.Methods A total of 24 healthy,adult and mongrel canines were randomly (random number) divided into three groups,namely control group (A),low Vt group (B) and high Vt group (C).Canines without ventricular fibrillation in group A were not supported with mechanical ventilation,while canines in group B and group C were induced to get ventricular fibrillation (VF) with pacing catheter inserted through right external carotid vein into the right ventricle.CPR was initiated with mechanical ventilation with different Vt for 6 hours after ventricular fibrillation.The Vt set in group B was 6 ml/kg body weight and Vt set in group C was 20 ml/kg body weight.The arterial blood gas analyses were tested in different intervals.The levels of phosphatidylchline in bronchia alveolus lavage fluid (BALF) was assayed with high performance liquid chromatography (HPLC).The ratio of wet and dry weight and the morphological change scores of lung tissue were calculated.Results After ventricular fibrillation,pH,PaO2 in both groups B and C decreased and PaCO2 increased in comparison with those before VF (P ＜ 0.05),while pH,PaO2 and PaCO2 were improved after mechanical ventilation.These was statistical difference in PaCO2 between group B and group C 2 h after mechanical ventilation (P ＜ 0.05).There was difference in HCO3-between group B and group C 6 h after ROSC.The rate of successful restoration of spontaneous circulation (ROSC) and the 72 h survival rate were 75％ and 50％ respectively in group B,and 62.5％ and 40％ respectively in group C.There were no statistically different between two groups (P ＞ 0.05).The levels of phosphatidylchline in BALF of group B and C greatly decreased compared with the group A (All P ＜0.01),while phosphatidylcholine detected in the group C decreased much more than that in the group B (P ＜0.01).The W/D ratio and morphological change scores in the group C were higher than those in the group B (P ＜ 0.01).Conclusion Low tidal volume ventilation can reduce the loss of pulmonary surfactant and mitigate pulmonary injury.Therefore it may be a protective ventilation strategy after resuscitation. Key words: Cardiopulmonary resuscitation; Mechanical ventilation ; Tidal volumes ; Lung injury ; Pulmonary surfactant

Evolution of Critical Care Cardiology: Transformation of the Cardiovascular Intensive Care Unit and the Emerging Need for New Medical Staffing and Training Models

Critical care, defined as the diagnosis and management of life-threatening conditions that require close or constant attention by a group of specially trained health professionals, is inherent to the practice of cardiovascular medicine. The demand for cardiovascular critical care is increasing with the aging of the population and is reflected by trends in the use of critical care in general.1 Between 2000 and 2005, although the total number of hospital beds in the United States declined by 4.2%, the number of critical care beds increased by 6.5% and the annual costs attributed to critical care increased by 44%, representing 13.4% of hospital costs.2 Projections for the next 15 years suggest that the need for critical care will increase markedly in the United States and globally.1,3–5 For example, in Canada, a 57% increase in the need for critical care beds is anticipated during that period.5 Concurrent with increases in demand, the medical demographics of general and cardiac critical care have evolved toward a patient population with an increasing number of comorbid medical conditions who require more prolonged and more technologically sophisticated invasive support. As a result, the delivery of critical care is advancing substantially in its complexity. Moreover, accumulating evidence has indicated that outcomes are better when critical care is provided by specially trained providers in a dedicated intensive care unit (ICU).6–9 In the context of this evolution, provision of optimal care in the contemporary cardiac ICU (CICU) presents a different set of challenges and requires an expanded set of skills compared with 10 years ago. Cardiovascular medicine has lagged behind other medical disciplines that have met the “critical care crisis”4 with ICU-focused innovations in organization, training, and quality improvement. Therefore, the American Heart Association Council on Cardiopulmonary, Critical …

Out-of-Hospital Cardiac Arrest

Sudden cardiac death (SCD), which is responsible for approximately 300 000 deaths in the United States, refers to an unexpected death from a cardiovascular cause in a person with or without preexisting heart disease. Most studies include cases that are associated with death occurring within 1 hour of an acute change in clinical status or an unexpected death that occurred within the previous 24 hours,1 but this definition is not specific for sudden arrhythmic death. The most common sequence of events leading to arrhythmic SCD is the degeneration of ventricular tachycardia (VT) into ventricular fibrillation (VF), often followed by asystole or pulseless electric activity. The transition of shockable rhythms (VT/VF) to more ominous rhythms such as asystole or pulseless electric activity depends on various factors, but is highly dependent on time; the longer the time interval, the more likely the VT/VF degenerates to pulseless electric activity or asystole. Although VF and VT together represent the initial rhythm in half of all outpatient cardiac arrests, data suggest that with each passing minute of untreated VF, the likelihood of survival is reduced by 7% to 10%.2 Preexisting coronary artery disease and its sequelae (eg, acute myocardial ischemia, scarring from previous myocardial infarction, heart failure) are manifest in 80% of SCDs.3 Dilated nonischemic and hypertrophic cardiomyopathies account for the second largest number of SCDs, whereas other cardiac disorders such as congenital heart disease and underlying genetically determined ion channel anomalies account for 5% to 10% of SCDs.3 Although the cascade of events triggering SCD are complex and are currently active areas of investigation, the general goals of reducing SCD are focused on (1) identifying and preventing sudden death in high-risk individuals by using efficacious therapies such as medications and implantable cardioverter defibrillators (ICDs), (2) organizing resuscitation services to improve …

Pro cardiopulmonary resuscitation before defibrillation

The medical dogma has always been to defibrillate a patient discovered to be in ventricular fibrillation (VF), and automatic electric defibrillators (AED) drove this standard into widespread cardiopulmonary resuscitation (CPR) guidelines. Slow AED operation and three stacked shocks added several minutes of not providing blood flow generated by chest compressions. Investigators questioned the practice of providing defibrillation first for patients with longer down time compared to providing chest compressions prior to defibrillation. Human and experimental literature in addition to the interplay between chest compression, defibrillation, and saving lives are discussed. The experimental and human literature published regarding chest compression prior to defibrillation is reviewed, the importance of providing chest compressions that generate adequate blood flow to vital organs is highlighted, and the scientific evidence for CPR before defibrillation was performed is explored. Our review documented that in experimental animal studies of cardiac arrest there is a pooling of blood on the venous side of the heart during VF and that chest compression before defibrillation serve two purposes: (1) high quality chest compressions preserve brain function and (2) perfusing the heart with blood,“primes it” for successful restoration of spontaneous circulation. In clinical practice, the time interval of CPR before defibrillation is unknown. One randomized trial of 3 min of CPR before defibrillation found a significant increase in survival for those who were reached more than 5 min after cardiac arrest, and this was supported by a study based on historic controls. Other studies have not found any benefit but we may speculate that this was due to the quality of the CPR. Delaying defibrillation attempts is meaningless, if quality of chest compressions is suboptimal. High quality CPR before defibrillation is the treatment of choice for those patients who will not receive a defibrillation attempt shortly after VF started. Regarding survival, it has not been documented that CPR first is inferior to defibrillation first. CPR first is safe and effective for most prehospital cardiac arrest patients.

Evaluation of cerebral metabolism by 1H-magnetic resonance spectroscopy for 4°C saline-induced therapeutic hypothermia in pig model of cardiac arrest

Background Previous studies have shown that therapeutic hypothermia could improve neurologic recovery when induced after cardiac arrest, but dynamic changes in cerebral metabolism have not been studied at low temperature. In this study, we aim to evaluate hypothermia-induced changes in pigs' cerebral metabolism by 1H-magnetic resonance spectroscopy ( 1H-MRS). Material and Methods Ten anesthetized Landrace (25-30 kg) pigs were randomized into 2 groups and subjected to 4 minutes of ventricular fibrillation, followed by cardiopulmonary resuscitation. The hypothermic group was given an infusion of 30 mL/kg of 4°C normal saline (NS) at an infusion rate of 1.33 mL/kg per minute starting after restoration of spontaneous circulation (ROSC), then 10 mL/kg per hour for 4 hours. The control group received the same infusion of room temperature NS. Core temperature and hemodynamic variables were monitored at baseline and repeatedly for 240 minutes after ROSC. The 1H-MRS scans were obtained at baseline, 1 hour, and 3 hours after successful ROSC to observe the dynamic changes of cerebral metabolism at different temperatures. Results The mean reduction of temperature was 1.5°C ± 0.4°C in the hypothermic group. There was no difference in hemodynamic variables between groups. 1H-MRS detected statistically significant ( P < .01) changes in cerebral metabolism between the control and hypothermia groups ( P < .01). Conclusions Infusion of 4°C NS can effectively reduce cerebral metabolism after successful cardiopulmonary resuscitation and have a protective effect on the recovery of neurologic function. The 1H-MRS technology can be used as a powerful tool to evaluate interventions in the treatment of cardiopulmonary resuscitation.

Good outcome in a patient with prolonged comatose state, critically elevated serum neuron-specific enolase and electroencephalic burst-suppression pattern

Introduction: The neurological outcome after cardiopulmonary resuscitation (CPR) is limited by the susceptibility of neurons to the lack of oxygen. Up to 70% of patients with successful restoration of spontaneous circulation (ROSC) later reach a state with severe neurological impairment. Several parameters have been identified in order to predict the neurological outcome after CPR. Prolonged or late-onset CPR, serum neuron-specific enolase (sNSE) values beyond time-related thresholds (33µg/l within 24 hours, 24–33µg/l within 48 hours, 35–40µg/l within 72 hours after ROSC), neurophysiological investigation revealing electroencephalic burst-suppression or generally suppressed patterns or bilateral loss of somatosensory evoked potentials (SEPs) are considered to be associated with a poor neurological outcome.

Assessment of intravascular volume by transthoracic echocardiography during therapeutic hypothermia and rewarming in cardiac arrest survivors

Aim To study haemodynamic effects and changes in intravascular volume during hypothermia treatment, induced by ice-cold fluids and maintained by ice-packs followed by rewarming in patients after resuscitation from cardiac arrest. Materials and methods In 24 patients following successful restoration of spontaneous circulation (ROSC), hypothermia was induced with infusion of 4 °C normal saline and maintained with ice-packs for 26 h after ROSC. This was followed by passive rewarming. Transthoracic echocardiography was performed at 12, 24 and 48 h after ROSC to evaluate ejection fraction and intravascular volume status. Central venous pressure (CVP), central venous oxygen saturation (ScvO 2) and serum lactate were measured. Fluid balance was calculated. Results Twelve hours after ROSC, two separate raters independently estimated that 10 and 13 out of 23 patients had a decreased intravascular volume using transthoracic echocardiography. After 24 and 48 h this number had increased further to 14 and 13 out of 19 patients and 13 and 12 out of 21 patients. Calculated fluid balance was positive (4000 ml the day 1 and 2500 ml day 2). There was no difference in ejection fraction between the recording time points. Serum lactate and ScvO 2 were in the normal range when echocardiography exams were performed. CVP did not alter over time. Conclusions Our results support the hypothesis that inducing hypothermia following cardiac arrest, using cold intravenous fluid infusion does not cause serious haemodynamic side effects. Serial transthoracic echocardiographic estimation of intravascular volume suggests that many patients are hypovolaemic during therapeutic hypothermia and rewarming in spite of a positive fluid balance.

Out-of-hospital surface cooling with a cooling-blanket to induce mild hypothermia in humans after cardiac arrest: a feasibility trial

Mild hypothermia (32–34°C) is a promising new therapy for patients resuscitated from cardiac arrest. Animal studies suggest that early and fast cooling is crucial for beneficial effect on neurological outcome. Inducing mild hypothermia immediately after successful restoration of spontaneous circulation (ROSC) in the out-of-hospital setting remains a challenge. Therefore, a novel cooling-blanket (EMCOOLSpad®), independent of any energy source during use, was developed. The aim of the study was to evaluate feasibility and safety of out-of-hospital surface cooling with EMCOOLSpad® in patients successfully resuscitated from cardiac arrest.

Survivors of ventricular tachyarrhythmias due to a transient or reversible disorder have a high recurrence rate of lethal cardiac events

Objectives: The recurrence rate of lethal cardiac events after the survival of a primary cardiac arrest in patients not having received an implantable cardioverter defibrillator (ICD) is investigated. Background: According to current guidelines, only a small percentage of patients after successful cardiopulmonary resuscitation due to an underlying cardiac problem are eligible for the implantation of an ICD. Methods: For retrospective analysis, we used a data registry of patients admitted to an emergency department after cardiac arrest. Patients who had a primary cardiac cause for their cardiac arrest and who did not die within the first month after successful restoration of spontaneous circulation were selected. Results: From 1246 patients, 360 met the inclusion criteria. A second lethal cardiac event occurred in 94 (26%). Of those 94 patients, 57 (61%) had good neurological function before their second cardiac arrest. Of the survivors with good neurological function, 47 (82%) did not have an ICD or a cardiac transplant. Another cardiac arrest due to a primary cardiac event occurred in 34 (72%) of these patients. Conclusions: Cardiac arrest survivors without an apparent indication for an ICD have a high risk of suffering from a re-arrest of cardiac origin.

Thrombolytic therapy after cardiac arrest and its effect on neurological outcome

Objective: the aim of the study is to investigate the effect of thrombolytic therapy on neurological outcome in patients after cardiac arrest due to acute myocardial infarction. Laboratory investigations have demonstrated that thrombolytic therapy after cardiopulmonary resuscitation improves neurological function. Methods: from July 1991 to June 1996, patients with witnessed ventricular fibrillation cardiac arrest due to acute MI and successful restoration of spontaneous circulation admitted to the emergency department were analyzed retrospectively. A logistic regression model was used to assess the association between thrombolytic therapy and neurological outcome [best cerebral performance category (CPC) within 6 months after cardiac arrest]. Results: all 157 patients [median age 57 years (IQR 50–69)] were analyzed. Thrombolytic therapy was applied in 42 patients (27%). With thrombolytic therapy good functional neurological recovery (CPC 1 or 2) was achieved more frequently (69 vs. 50%, P=0.03). After controlling for age, prehospital dosage of epinephrine, and the duration of cardiac arrest we found a non significant trend towards good neurological recovery when thrombolytic therapy was given (OR 1.9, 95% CI 0.8–4.6). Conclusion: thrombolytic therapy after cardiac arrest due to acute myocardial infarction is associated with improved neurological outcome.

Outcome of in-Hospital Pediatric Cardiac Arrest

The outcome of pediatric cardiac arrest is poor, and attempts to improve it have not been very successful. The aim of this study was to analyze the outcome of a large number of in-hospital pediatric cardiac arrest patients, and to determine the factors that influence this outcome. The records of hospital inpatients at King Faisal Specialist Hospital and Research Centre who received external cardiac massage as part of their cardiopulmonary resuscitation were reviewed. Success of resuscitation was analyzed as: 1) short-term (restoration of spontaneous circulation); and 2) long-term (discharge from hospital). Of 234 such patients, 171 (73.1%) survived the initial resuscitation, and 66 (28.2%) were discharged from hospital. Success of outcome was not related to age, time of day, or location of arrest. Longer resuscitation time was associated with less chance of restoration of spontaneous circulation (P<0.001), and lower hospital discharge rate. RESULTS for patients with congenital heart disease were similar to those with other medical or surgical conditions. Restoration of spontaneous circulation from asystole was more difficult when compared to other arrest rhythm, but once circulation was restored, long-term outcome was not influenced by rhythm. Asystole and longer resuscitation time are associated with poorer outcome, however, successful restoration of spontaneous circulation with long-term survival can be achieved after prolonged resuscitation.

Outcome of In-hospital Pediatric Cardiac Arrest 208

Background: The outcome of pediatric cardiac arrest is poor, and attempts to improve it have not been very successful. The aim of this study was to analyze the outcome of a large number of in-hospital pediatric cardiac arrest patients, and to determine the factors that influence this outcome. Patients and Methods: The records of hospital inpatients at King Faisal Specialist Hospital and Research Centre who received external cardiac massage as part of their cardiopulmonary resuscitation were reviewed. Success of resuscitation was analyzed as: 1) short-term (restoration of spontaneous circulation); and 2) long-term (discharge from hospital). Results: Of 234 such patients, 171 (73.1%) survived the initial resuscitation, and 66 (28.2%) were discharged from hospital. Success of outcome was not related to age, time of day, or location of arrest. Longer resuscitation time was associated with less chance of restoration of spontaneous circulation (P<0.001), and lower hospital discharge rate. Results for patients with congenital heart disease were similar to those with other medical or surgical conditions. Restoration of spontaneous circulation from asystole was more difficult when compared to other arrest rhythm, but once circulation was restored, long-term outcome was not influenced by rhythm. Conclusion: Asystole and longer resuscitation time are associated with poorer outcome, however, successful restoration of spontaneous circulation with long-term survival can be achieved after prolonged resuscitation. Ann Saudi Med 1998;18(3):208-211.

'Low T3syndrome' in a pig model of cardiopulmonary resuscitation - the time-course of changes in thyroid hormones and plasma catecholamines

Objective: To investigate the time-course of changes in thyroid hormone and plasma catecholamine levels after administration of epinephrine, norepinephrine or vasopressin in a pig model of cardiopulmonary resuscitation (CPR). Design: Prospective, randomised controlled study. Setting: Animal care facility, Department of Experimental Anaesthesia. Subjects: A total of 21 pigs. Interventions: The pigs were randomly allocated to receive either 45 μg/kg epinephrine (epi, n=7), 45 μg/kg norepinephrine (norepi, n=7), or 0.8 IU/kg vasopressin (vaso, n=7) after 4 minutes of ventricular fibrillation and 3 minutes of open chest CPR. Measurements and main results: Arterial blood samples were obtained before CPR (pre-arrest), during mechanical CPR, ie before drug administration (DA), 5 minutes after DA and 60 and 180 minutes after restoration of spontaneous circulation (ROSC) for radioimmunological detection of iodothyronine serum concentration (total triiodothyronine TT3 ng/dl, thyroxine TT4 μg/dl, reverse triiodothyronine rT3 ng/dl, free unbound thyroxine fT4 ng/dl [equilibrium dialysis]). At the same time-points plasma catecholamine levels were measured by high pressure liquid chromatography (HPLC). Short-term ROSC was accomplished with epinephrine, norepinephrine or vasopressin in all animals. Even during CPR, all animals exhibited a rapid decrease of TT3. Irrespective of the drug given for CPR, the animals demonstrated a significant and sustained disappearance of TT3 180 minutes after ROSC (pre-arrest: epi group 55±10.7, norepi group 67±14.6, vaso group 42±6.4; 180 minutes after ROSC: epi group 14±3.4*, norepi group 18±5.6*, vaso group 14±3.4* ng/dl, *p&lt;0.05). This was accompanied by a significant increase of rT3 180 minutes after ROSC (pre-arrest: epi group 22.5±2.2, norepi group 24±5.0, vaso group 23±1.7; 180 minutes after ROSC: epi group 52±7.3*, norepi group 45±8.8*, vaso group 43±5.8* ng/dl, *p&lt;0.05). Vasopressin-treated animals exhibited significantly lower plasma levels of epinephrine and norepinephrine after drug administration. However, these differences in plasma catecholamines during CPR influenced neither the time-course nor the extent of change in thyroid hormone indices during and after CPR. Conclusions: Our data demonstrate the rapid development of a low T3 and high rT3 syndrome in a pig model of CPR within 3 hours following cardiac arrest and successful ROSC. Thyroid hormone metabolism is rapidly involved in the endocrine response to maximal stress during and after cardiac arrest. Neither the drug treatment during CPR nor the different plasma catecholamines concentrations affected the time-course and extent of changes in thyroid hormone status in this animal model.

Manual open-chest cardiopulmonary resuscitation

Although the mechanistic differences between standard external cardiopulmonary resuscitation (SCPR) and open-chest CPR (OCCPR) are clear, it remains unclear when OCCPR offers a benefit over SCPR for nontraumatic cardiac arrest. Experimentally OCCPR has been shown to generate much higher arterial and much lower venous pressures, resulting in increased perfusion pressures across both heart and brain. Most studies have shown increased blood flow with OCCPR. Mechanical OCCPR has been shown to sustain electroencephalographic activity for up to one hour after up to four minutes of arrest. It has been shown in several studies that cardiac resuscitability is greater with OCCPR than with SCPR. Cerebral blood flow approaches normal with OCCPR; the best reported for SCPR is 50% of normal. After four minutes of cardiac arrest, OCCPR for 30 minutes does not yield a neurological deficit significantly different from immediate defibrillation; all animals studied returned to nearly normal by 24 hours postresuscitation. After the same arrest time, nearly all animals receiving either SCPR or simultaneous ventilation-compression CPR for 30 minutes were dead by 24 hours. Clinically early series reported up to 28% survivorship (patients discharged home) after OCCPR. Survivors after up to 2.5 hours of OCCPR and after successful restoration of spontaneous circulation by OCCPR after failure of SCPR for 75 minutes have been reported. Reported incidences of wound infection and iatrogenic cardiac injury range from 0 to 9.1% and 0 to 1.4%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)