Decrease in the occurrence of ventricular fibrillation as the initially observed arrhythmia after out-of-hospital cardiac arrest during 11 years in Sweden

Aim: To describe the change in the occurrence of ventricular fibrillation as initially observed arrhythmia among patients suffering from out-of-hospital cardiac arrest in Sweden. Patients: All patients included in the Swedish cardiac arrest registry between 1991 until 2001. The registry covers 85% of the population in Sweden. Methods: All patients with bystander witnessed out-of-hospital cardiac arrest included in the Swedish Cardiac Arrest Registry between 1991 and 2001 from the same ambulance organisation each year were included in the survey. Results: Over 11 years, among patients in Sweden with a bystander witnessed out-of-hospital cardiac arrest in whom cardiopulmonary resuscitation (CPR) was attempted (n=9666), the occurrence of ventricular fibrillation as the initially obseved arrhythmia decreased from 45% in 1991 to 28% in 2001 (P<0.0001) if the arrest occurred at home, and from 57% to 41% if the arrest occurred outside home (P<0.0001). This was found despite the fact that the proportion who received bystander CPR increased from 29% in 1991 to 39% in 2001 if the arrest occurred at home (P<0.0001) and from 54% to 60% if the arrest occurred outside home (NS). There was a significant increase in age among patients with out-of-hospital cardiac arrest at home, no change in the estimated interval between collapse and call but an increase in the interval between call and arrival of the ambulance among patients with out-of-hospital cardiac arrest outside home. Conclusion: During 11 years in Sweden, there was a marked decrease in the proportion of patients found in ventricular fibrillation among patients with a bystander witnessed cardiac arrest regardless whether the arrest occurred at home or outside home. A modest increase in age and interval between call for, and arrival of, the ambulance was associated with these findings.     

Effects of intraaortic balloon augmentation in a porcine model of endotoxemic shock

Objective: Patients with septic shock commonly have myocardial dysfunction associated with lactic acid production and troponin I release. The purpose of this study was to evaluate the effects on intraaortic balloon pump (IABP) support on myocardial dysfunction. Design: Prospective, randomized controlled study. Setting: Animal research laboratory. Methods: Ten pigs had arterial, pulmonary arterial, and coronary catheters inserted. After receiving endotoxin infusion over 30 min, half the animals received IABP support. Results: Coronary sinus lactic acid levels (P<0.05 for both 90 min versus baseline and 60 min versus baseline) and arterial lactic acid levels (P<0.05 for both 90 min versus baseline and 60 min versus baseline) increased with time but did not differ between IABP and sham groups. While overall there was no difference with time in myocardial lactic acid consumption or production (calculated as arterial lactic acid level minus coronary sinus lactic acid level), the IABP group showed net myocardial lactic acid consumption at 90 min, while the sham group showed myocardial lactic acid production. Three of five animals in each group showed troponin I release. The levels were similar and did not differ between groups. Conclusion: IABP had no benefits in this porcine model of endotoxemic shock.     

Cardiopulmonary resuscitation (CPR) using periodic acceleration (pGz) in an older porcine model of ventricular fibrillation

Cardiopulmonary resuscitation (CPR) can be achieved by repetitive motion of the body headwards to footwards in the spinal axis, at 2 Hz and ±0.6 G in a juvenile pig model of ventricular fibrillation. Return of spontaneous circulation and normal neurological outcome occurred after a total of 22 min of ventricular fibrillation that included a 3-min noninterventional period [Resuscitation 56 (2003) 215; Resuscitation 51 (2001) 55]. Since older pigs have stiffer rib cages than juvenile pigs and their hemodynamic response to various stimuli might differ, this study was carried out to determine whether this method of CPR, termed pGz-CPR, was just as effective in older pigs. pGz-CPR was also compared to chest compression CPR using an automated mechanical device (CONV-CPR). Ventricular fibrillation was instituted in older pigs weighing 23–34 kg and a 3-min noninterventional period was observed, followed by 15 min pGz-CPR in eight pigs or 15 min CONV-CPR in eight pigs. Return of spontaneous circulation (ROSC) occurred after defibrillation in all eight pigs with pGz-CPR and in six of eight pigs with CONV-CPR. Two of eight pigs with CONV-CPR and none of the eight pigs with pGz-CPR had rib fractures. Hemodynamic instability 15 min after ROSC occurred in all animals with CONV-CPR whereas only three of eight pigs with pGz-CPR demonstrated hemodynamic instability (P<0.05). We conclude that pGz-CPR in older pigs produces similar ROSC reported by other investigators in pigs without the risk of rib fractures. Further, pGz-CPR is associated with a lower incidence of periods of hemodynamic instability following ROSC than CONV-CPR.     

Does race or socioeconomic status predict adverse outcome after out of hospital cardiac arrest: a multi-center study

Objective: To assess whether socioeconomic status (SES) or race is associated with adverse outcome after an out-of-hospital cardiac arrest (OHCA). Methods: A convenience sample of OHCA of presumed cardiac origin from seven suburban cities in Michigan, 1991–1996. Median household income (HHI), utilizing patient home address and 1990 census tract data, was dichotomized above and below 1990 state median income. Patient race was dichotomized as black or white. Outcome was defined as survival to hospital discharge (DC). Multiple logistic regression and Pearson’s χ² values were used for analysis. Results: Of 1317 cases with complete data for analysis, the average age was 67.3±16.0, 939 (71.1%) were white, 587 (44.4%) arrests were witnessed (WIT), and 65 (4.9%) were DC alive. There was no significant difference between races with respect to WIT arrests, V_T/V_F arrest rhythms, and a small difference in EMS response interval. Whites were more likely to be above median HHI (57.1 vs. 26.2%, P<0.001). Adjusted odds ratios for predictors of survival were WIT arrest (OR=3.76, 95% CI (1.7, 8.2)), V_T/V_F (OR=8.74, 95% CI (3.7, 10.8), but not race (OR=0.68, 95% CI (0.3, 1.4)) or SES (OR=1.51,95% CI 0.8, 2.8). Conclusion: In this population, neither race nor SES was independently associated with a worse outcome after OHCA.     

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.     

Addition of ketamine to propofol–fentanyl anaesthesia can reduce post-operative pain and epidural analgesic consumption in upper abdominal surgery

The aim of this study was to confirm whether intravenous anaesthesia supplemented with the N-methyl- -aspartate (NMDA) antagonist ketamine could reduce post-operative pain after elective open cholecystectomy. Fifty patients were randomised double-blind to one of the following two groups: PF Group received propofol and fentanyl supplemented with saline infusion; PFK Group received propofol and fentanyl supplemented with ketamine (total dose 2 mg/kg). During the first 48 post-operative hours, epidural analgesia was provided for all patients with patient-controlled epidural analgesia (PCEA) using 0.125% bupivacaine and morphine (0.05 mg/ml). Pain assessments at rest and movement, and cumulative PCEA volume consumed, were recorded at 5, 24 and 48 h post-operatively. The visual analogue scale (VAS) scores at rest were significantly less in the PFK Group than in the PF Group at 5, 24 and 48 h (P<0.001, P<0.001 and P=0.02, respectively). The VAS score at movement were also significantly (P<0.001) less throughout this study than in the PF Group. The difference in PCEA analgesic consumption at 0–5 and 5–24 h reached statistical significance (P<0.001 and P=0.008, respectively). Our results show that an intra-operative ketamine dose provides advantages for post-operative analgesia beyond its duration of action after an open cholecystectomy.     

Laryngeal mask airway in neonatal resuscitation: a survey of current practice and perceived role by anaesthesiologists and paediatricians

Objectives: To survey current practice and to compare the opinion of paediatricians and anaesthesiologists regarding laryngeal mask airway (LMA) in neonatal resuscitation. Design: A structured postal questionnaire on the use of the laryngeal mask airway in neonatal resuscitation was sent to the heads of department of the paediatric and anaesthesiology services. Setting: Forty-three hospitals in the Veneto Region, Italy. Results: During the year 2000, 1526 out of 33708 (4.5%) neonates in our region needed resuscitation. Of these cases, 101 (6.6%) were ventilated using the LMA. Laryngeal mask airway availability was significantly greater in the anaesthesiology department compared to the paediatric department (90% versus 50%; P=0.002). However, 52% of anaesthesiologists and 72% of paediatricians had never used the laryngeal mask airway in their practice. The laryngeal mask airway was considered as an essential device more frequently by the anaesthesiologists than by the paediatricians (27% versus 5%; P=0.015); both groups considered the laryngeal mask airway particularly useful in specific situations. Interestingly, while 16% of the paediatricians described the laryngeal mask airway as having no value, none of the anaesthesiologists did (P=0.002). Staff competence was considered low by 70% of anaesthesiology heads of department compared with 90% of their pediatric colleagues. In both specialties, use of the laryngeal mask airway was limited to medical staff. With regard to training, 35% of anaesthesiologists and 22.5% of paediatricians had attended a course on laryngeal mask airway use. Conclusions: Laryngeal mask airway availability and perceived value were higher amongst anaesthesiologists than their paediatric colleagues. However, educational level, competence and utilization rates of the LMA in neonatal resuscitation were low in both groups.     

Recovery from near death following cerebral anoxia: A case report demonstrating superiority of median somatosensory evoked potentials over EEG in predicting a favorable outcome after cardiopulmonary resuscitation

An electroencephalogram disclosing electrocerebral silence (ECS) after cardiopulmonary resuscitation (CPR) is usually considered an unfavorable prognostic indicator associated with brain death or persistent vegetative state. I report a case of a comatose patient following cardiac arrest, whose initial electroencphalography (EEG) was isoelectric taken 5 h after onset. Median somatosensory evoked potentials (SSEP) obtained immediately after the initial EEG were normal. He then underwent gradual recovery of neurologic function with incremental improvement on serial EEG study, and eventually achieved full neurological recovery. SSEP proved to be a more reliable predictor of a neurological outcome that was ultimately favorable.     

There is a difference in characteristics and outcome between women and men who suffer out of hospital cardiac arrest

Objective: To evaluate whether there is a difference in characteristics and outcome in relation to gender among patients who suffer out of hospital cardiac arrest. Design: Observational study. Setting: The community of Göteborg. Patients: All patients in the community of Göteborg who suffered out of hospital cardiac arrest between 1980 and 1996, and in whom cardiopulmonary resuscitation (CPR) was initiated. Main outcome measures: Factors at resuscitation and the proportion of patients being hospitalized and discharged from hospital. P values were corrected for age. Results: The women were older than the men (median of 73 vs. 69 years; P<0.0001), they received bystander-CPR less frequently (11 vs. 15%; P=0.003), they were found in ongoing ventricular fibrillation less frequently (28 vs. 44%; P<0.0001), and their arrests were judged to be of cardiac origin less frequently. In a multivariate analysis considering age, gender, arrest being due to a cardiac etiology, initial arrhythmia and by-stander initiated CPR, female gender appeared as an independent predictor for patients being brought to hospital alive (odds ratio 1.37; P=0.001) but not for patients being discharged from hospital. Conclusion: Among patients who suffer out of hospital cardiac arrest with attempted CPR women differ from men being older, receive bystander CPR less frequently, have a cardiac etiology less frequently and are found in ventricular fibrillation less frequently. Finally female gender is associated with an increased chance of arriving at hospital alive.     

A randomized trial of suprasternal palpation to determine endotracheal tube position in neonates

Objective: To compare suprasternal palpation, a previously described bedside technique, with standard chest radiography for correct positioning of the endotracheal tube (ETT) in newborn infants. Study design: A randomized single-blinded study in an academic medical center. Preterm and term newborn infants requiring intubation were eligible, provided that they had not had their initial chest roentgenogram (CXR). Infants were randomized to ETT palpation and non-adjustment (Controls), or to ETT palpation and adjustment (Treatment), following digital palpation of the ETT tip in the suprasternal notch. ETT position was considered correct when only the tip of the ETT was palpable in the suprasternal notch. ETT position by CXR was blindly assessed by an experienced pediatric radiologist. Results: Fifty-five infants were enrolled in the delivery room or neonatal intensive care unit. Correct tube placements improved from 48% pre-study to 85 and 93% in the Control and Treatment arms, respectively. The majority of incorrect estimations were that the ETT position using palpation was judged to be too low when it was, in fact, in correct position, as noted in 11 infants. ETT palpation had a 70% concordance with the position determined by CXR. No difficulties or complications were associated with the use of suprasternal palpation. Conclusions: Suprasternal palpation is a simple, safe, teachable, method of confirming ETT position in neonates when CXR is unavailable, and may especially helpful during neonatal resuscitation prior to surfactant administration.