Skills among young and elderly laypersons during simulated dispatcher assisted CPR and after CPR training.

BACKGROUND: Dispatcher assisted cardiopulmonary resuscitation (DA-CPR) increase the rate of bystander CPR. The aim of the study was to compare the performance of DA-CPR and attainable skills following CPR training between young and elderly laypersons. METHODS: Volunteer laypersons (young: 18-40 years; elderly: > 65 years) participated. Single rescuer CPR was performed in a simulated DA-CPR cardiac arrest scenario and after CPR training. Data were obtained from a manikin and from video recordings. The primary endpoint was chest compression depth. RESULTS: Overall, 56 young (median age: 26, years since last CPR training: 6) and 58 elderly (median age: 72, years since last CPR training: 26.5) participated. Young laypersons performed deeper (mean (SD): 56 (14) mm vs. 39 (19) mm, P < 0.001) and faster (median (25th-75th percentile): 107 (97-112) per min vs. 84 (74-107) per min, P < 0.001) chest compressions compared to elderly. Young laypersons had shorter time to first compression (mean (SD): 71 (11) seconds vs. 104 (38) seconds, P < 0.001) and less hands-off time (median (25th-75th percentile): 0 (0-1) seconds vs. 5 (2-10) seconds, P < 0.001) than elderly. After CPR training chest compressions were performed with a depth (mean (SD): 64 (8) mm vs. 50 (14) mm, P < 0.001) and rate (mean (SD): 111 (11) per min vs. 93 (18) per min, P < 0.001) for young and elderly laypersons respectively. CONCLUSION: Despite long CPR retention time for both groups, elderly laypersons had longer retention time, and performed inadequate DA-CPR compared to young laypersons. Following CPR training the attainable CPR level was of acceptable quality for both young and elderly laypersons.

Reduced right ventricular diameter during cardiac arrest caused by tension pneumothorax - a porcine ultrasound study.

INTRODUCTION: Advanced life support (ALS) guidelines recommend ultrasound to identify reversible causes of cardiac arrest. Right ventricular (RV) dilatation during cardiac arrest is commonly interpreted as a sign of pulmonary embolism. The RV is thus a focus of clinical ultrasound examination. Importantly, in animal studies ventricular fibrillation and hypoxia results in RV dilatation. Tension pneumothorax (tPTX) is another reversible cause of cardiac arrest, however, the impact on RV diameter remains unknown. AIM: To investigate RV diameter evaluated by ultrasound in cardiac arrest caused by tPTX or hypoxia. METHODS: Pigs were randomized to cardiac arrest by either tPTX (n = 9) or hypoxia (n = 9) and subsequently resuscitated. Tension pneumothorax was induced by injection of air into the pleural cavity. Hypoxia was induced by reducing tidal volume. Ultrasound images of the RV were obtained throughout the study. Tension pneumothorax was decompressed after the seventh rhythm analysis. The primary endpoint was RV diameter after the third rhythm analysis. RESULTS: At cardiac arrest the RV diameter was 17 mm (95% CI: 13; 21) in the tPTX group and 36 mm (95% CI: 33; 40) in the hypoxia group (P < 0.01, n = 9 for both). At third rhythm analysis RV diameter was smaller in the tPTX group: 12 mm (95% CI: 7; 16) vs. hypoxia group: 28 mm (25; 32) (P < 0.01). After decompression no difference existed between groups: tPTX 29 mm (95% CI: 23; 34) vs. hypoxia 29 mm (95% CI: 20; 38). CONCLUSION: The RV diameter is smaller during cardiopulmonary resuscitation in cardiac arrest caused by tPTX when compared with hypoxia. The difference disappears after tPTX decompression.

A randomised crossover comparison of manikin ventilation through Soft Seal®, i-gel™ and AuraOnce™ supraglottic airway devices by surf lifeguards.

Forty surf lifeguards attempted to ventilate a manikin through one out of three supraglottic airways inserted in random order: the Portex® Soft Seal®; the Intersurgical® i-gel™; and the Ambu® AuraOnce™. We recorded the time to ventilate and the proportion of inflations that were successful, without and then with concurrent chest compressions. The mean (SD) time to ventilate with the Soft Seal, i-gel and AuraOnce was 35.2 (7.2)s, 15.6 (3.3)s and 35.1 (8.5) s, respectively, p < 0.0001. Concurrent chest compression prolonged the time to ventilate by 5.0 (1.3-8.1)%, p = 0.0072. The rate of successful ventilations through the Soft Seal (100%) was more than through the AuraOnce (92%), p < 0.0001, neither of which was different from the i-gel (97%). The mean (SD) tidal volumes through the Soft Seal, i-gel and AuraOnce were 0.65 (0.14) l, 0.50 (0.16) l and 0.39 (0.19) l, respectively. Most lifeguards (85%) preferred the i-gel. Ventilation through supraglottic airway devices may be considered for resuscitation by surf lifeguards.

A randomised crossover comparison of mouth-to-face-shield ventilation and mouth-to-pocket-mask ventilation by surf lifeguards in a manikin.

Thirty surf lifeguards (mean (SD) age: 25.1 (4.8) years; 21 male, 9 female) were randomly assigned to perform 2 × 3 min of cardiopulmonary resuscitation on a manikin using mouth-to-face-shield ventilation (AMBU LifeKey) and mouth-to-pocket-mask ventilation (Laerdal Pocket Mask). Interruptions in chest compressions, effective ventilation (visible chest rise) ratio, tidal volume and inspiratory time were recorded. Interruptions in chest compressions per cycle were increased with mouth-to-face-shield ventilation (mean (SD) 8.6 (1.7) s) compared with mouth-to-pocket-mask ventilation (6.9 (1.2) s, p < 0.0001). The proportion of effective ventilations was less using mouth-to-face-shield ventilation (199/242 (82%)) compared with mouth-to-pocket-mask ventilation (239/240 (100%), p = 0.0002). Tidal volume was lower using mouth-to-face-shield ventilation (mean (SD) 0.36 (0.20) l) compared with mouth-to-pocket-mask ventilation (0.45 (0.20) l, p = 0.006). No differences in inspiratory times were observed between mouth-to-face-shield ventilation and mouth-to-pocket-mask ventilation. In conclusion, mouth-to-face-shield ventilation increases interruptions in chest compressions, reduces the proportion of effective ventilations and decreases delivered tidal volumes compared with mouth-to-pocket-mask ventilation.

Exercise-induced cardioprotection is mediated by a bloodborne, transferable factor.

Exercise protects against myocardial ischemia-reperfusion (I-R) injury but the mechanism remains unclear. Protection can be transferred from a remotely preconditioned human donor to an isolated perfused rabbit heart using a dialysate of plasma. We hypothesized that physical exercise preconditioning also confers cardioprotection through a humorally mediated effector dependent on opioid receptor activation. Thirteen male volunteers performed vigorous exercise (four 2-minute bouts of high-intensity exercise) and 1 week later they underwent remote ischemic preconditioning (four cycles of 5 min upper limb ischemia and reperfusion). Dialysates were prepared from blood collected before (control) and after the two interventions. Isolated rabbit hearts were perfused with the dialysates without and with co-administration of naloxone (opioid receptor antagonist) prior to 40 min regional ischemia and 2 h reperfusion. Exercise and remote ischemic preconditioning (rIPC) reduced infarct size from 60 ± 5 to 35 ± 5 % and from 57 ± 7 to 27 ± 3 % of the area at risk, respectively (p < 0.05 and < 0.01). Furthermore, post-ischemic left ventricular developed pressure was improved compared with controls (p = 0.08 for exercise and p = 0.04 for rIPC). Co-perfusion with naloxone abrogated the protective effects of exercise and remote ischemic preconditioned dialysates. In conclusion, high-intensity exercise preconditioning elicits cardioprotection through a humorally mediated dependent on opioid receptor activation, similar to rIPC.

Comparison of two sulfonylureas with high and low myocardial K(ATP) channel affinity on myocardial infarct size and metabolism in a rat model of type 2 diabetes.

AIMS/HYPOTHESIS: Sulfonylureas (SUs) may impair outcome in patients with acute coronary syndrome. Most experimental studies of the myocardial effects of SU treatment are performed in non-diabetic models. We compared the effect of two widely used SUs, glibenclamide (gb) and gliclazide (gc), with high and low myocardial K(ATP) channel affinity, respectively, at therapeutic concentrations on infarct size, left ventricular (LV) function and myocardial glycogen, lactate and alanine content before and after ischaemia/reperfusion (I/R). METHODS: Non-diabetic Wistar and diabetic Goto-Kakizaki rat hearts were investigated in a Langendorff preparation. Gb (0.1 µmol/l) and gc (1.0 µmol/l) were administrated throughout the study. Infarct size was evaluated after 120 min of reperfusion. Myocardial metabolite content was measured before and after ischaemia. RESULTS: Infarct size was smaller in diabetic hearts than in non-diabetic hearts (0.33 ± 0.03 vs 0.51 ± 0.05, p < 0.05). Gb increased infarct size (0.54 ± 0.04 vs 0.33 ± 0.03, p < 0.05) and reduced post-ischaemic LV developed pressure (60 ± 3 vs 76 ± 3 mmHg, p < 0.05) and coronary flow (4.9 ± 0.5 vs 7.1 ± 0.4 ml min(-1) g(-1), p < 0.05) in gb-treated diabetic rats compared with untreated diabetic rats. On comparing gb-treated diabetic rats with untreated diabetic rats, glycogen content was reduced before (9.1 ± 0.6 vs 13.6 ± 1.0 nmol/mg wet weight, p < 0.01) and after ischaemia (0.9 ± 0.2 vs 1.8 ± 0.2 nmol/mg wet weight, p < 0.05), and lactate (4.8 ± 0.4 vs 3.2 ± 0.3 nmol/mg wet weight, p < 0.01) and alanine (1.38 ± 0.12 vs 0.96 ± 0.09 nmol/mg wet weight, p < 0.05) contents were increased during reperfusion. Gc-treatment of diabetic and non-diabetic rats did not affect any of the measured variables. CONCLUSIONS/INTERPRETATIONS: Gb, but not gc, exacerbates I/R injury and deteriorates LV function in diabetic hearts. These effects of gb on diabetic hearts may be due to detrimental effects on myocardial carbohydrate metabolism.

PKCepsilon, via its regulatory domain and independently of its catalytic domain, induces neurite-like processes in neuroblastoma cells.

To investigate the role of protein kinase C (PKC) isoforms in regulation of neurite outgrowth, PKCalpha, betaII, delta, and epsilon fused to enhanced green fluorescent protein (EGFP) were transiently overexpressed in neuroblastoma cells. Overexpression of PKCepsilon-EGFP induced cell processes whereas the other isoforms did not. The effect of PKCepsilon-EGFP was not suppressed by the PKC inhibitor GF109203X. Instead, process formation was more pronounced when the regulatory domain was introduced. Overexpression of various fragments from PKCepsilon regulatory domain revealed that a region encompassing the pseudosubstrate, the two C1 domains, and parts of the V3 region were necessary and sufficient for induction of processes. By deleting the second C1 domain from this construct, a dominant-negative protein was generated which suppressed processes induced by full-length PKCepsilon and neurites induced during retinoic acid- and growth factor-induced differentiation. As with neurites in differentiated neuroblastoma cells, processes induced by the PKCepsilon- PSC1V3 protein contained alpha-tubulin, neurofilament-160, and F-actin, but the PKCepsilon-PSC1V3-induced processes lacked the synaptic markers synaptophysin and neuropeptide Y. These data suggest that PKCepsilon, through its regulatory domain, can induce immature neurite-like processes via a mechanism that appears to be of importance for neurite outgrowth during neuronal differentiation.

Cardioprotective effect of L-glutamate in obese type 2 diabetic Zucker fatty rats.

1. Because diabetic hearts have an increased threshold for cardioprotection by ischaemic preconditioning (IPC), we hypothesized that protection by L-glutamate during reperfusion is restricted in Type 2 diabetic hearts. Previously, we found that L-glutamate-mediated postischaemic cardioprotection mimics IPC. 2. Rat hearts were studied in a Langendorff preparation perfused with Krebs'-Henseleit solution and subjected to 40 min global no-flow ischaemia, followed by 120 min reperfusion. L-Glutamate (0, 15 and 30 mmol/L) was added to the perfusate during reperfusion of hearts from non-diabetic (Wistar-Kyoto) and diabetic (Zucker diabetic fatty (ZDF)) rats, studied at 16 weeks of age. The infarct size (IS)/area-at-risk (AAR) ratio was the primary end-point. Expression of L-glutamate excitatory amino acid transporter (EAAT) 1 (mitochondrial) and EAAT3 (sarcolemmal) was determined by quantitative polymerase chain reaction and immunoblotting. 3. The ISS/AAR ratio did not differ between control hearts from Wistar-Kyoto and ZDF rats (0.52 ± 0.03 and 0.51 ± 0.04, respectively; P = 0.90). L-Glutamate (15 mmol/L) significantly reduced the IS/AAR ratio in non-diabetic hearts, but not in diabetic hearts, compared with their respective controls. The higher concentration of L-glutamate (30 mmol/L) reduced infarct size in diabetic hearts to the same degree as in non-diabetic hearts (IS/AAR 0.35 ± 0.03 (P = 0.002) and 0.34 ± 0.03 (P = 0.004), respectively). The mitochondrial L-glutamate transporter EAAT1 was downregulated in hearts from ZDF rats at both the mRNA and protein levels (P < 0.0005 and P < 0.0001, respectively). However, there was no change in EAAT3 expression at the protein level. Myocardial L-glutamate content was increased by 43% in diabetic hearts (P < 0.0001). 4. Hearts from obese diabetic rats have an elevated threshold for metabolic postischaemic cardioprotection by L-glutamate. These findings may reflect underlying mechanisms of inherent resistance against additional cardioprotection in the diabetic heart.

Validation of a fall risk index in stroke rehabilitation.

A fall risk index has previously been developed to identify fall-prone individuals in stroke rehabilitation. The purpose of this study was to validate the predictive accuracy of the index. The validation sample (n = 158) consisted of patients admitted to a specialized geriatric stroke rehabilitation ward. The index was scored for each subject, and the relationship between the score and falls was assessed. The index was then remodeled and cross-validated in the sample from which it was derived (model fit sample, n = 135). The total index score (0-11) was significantly connected with the time to first fall (hazard ratio, 1.22; confidence interval [CI], 1.03-1.44). However, the classification of subjects into groups with low, intermediate, and high risk of falling could not be correlated with the time to first fall. A remodeled index contained 3 of the separate original index items. Its relationship to fall risk in the model fit sample was (hazard ratio, 1.82; CI, 1.38-2.40). The fall risk index showed some correlation with the fall risk among patients in stroke rehabilitation, but the results indicate that it should be modified to reach acceptable accuracy. A remodeled index showed a higher association with fall risk.

Bronchoscopic diagnosis of pulmonary infections in a heterogeneous, nonselected group of patients.

Fiberoptic bronchoscopy with bronchoalveolar lavage and protected specimen brush technique has become an established method for etiologic diagnosis in severe forms of pulmonary infections during recent years. In this study, including 62 bronchoscopies in 53 patients, a standardized program, covering all important pulmonary pathogens, has been evaluated in a heterogeneous group of patients. Results providing therapeutic guidelines were obtained in 53 percent (16/30) of the immunocompromised patients (including 5 bronchoscopies on HIV-positive patients), but only 19 percent (6/32) of the immunocompetent patients (p < 0.001). We conclude that bronchoscopy is of great value for diagnosing pulmonary infections in immunocompromised patients. In immunocompetent patients, the diagnostic yield is lower and the indication for bronchoscopy must be established for each individual patient based on clinical importance, resources, and risk. When bronchoscopy is performed, we believe that a standardized program like ours reduces the risk of missing important pathogens.

Inhibition of RNA- and DNA-dependent duck hepatitis B virus DNA polymerase activity by nucleoside and pyrophosphate analogs.

The DNA polymerase of hepadnaviruses has two different functions during virus replication. It acts both as an RNA-dependent DNA polymerase (reverse transcriptase) and as a DNA-dependent DNA polymerase. Duck hepatitis B virus (DHBV) preparations were used to investigate the inhibitory effects of selected compounds on these two enzyme activities. The reverse transcriptase activity was represented by an actinomycin D-resistant, phosphonoformate-sensitive DNA polymerase activity isolated from DHBV-infected duck livers. DHBV from serum was used as the source of the DNA-dependent DNA polymerase activity. Pyrophosphate and nucleoside triphosphate analogs were assayed for their inhibitory effects on the two enzyme preparations. A marked inhibition was obtained with 3'-fluoro-2',3'-dideoxythymidine 5'-triphosphate, acyclovir triphosphate, 2',3'-dideoxythymidine 5'-triphosphate, 2',3'-dideoxyguanosine 5'-triphosphate and 2',3'-dideoxythymidine 5'-triphosphate. The two thymidine analog triphosphates showed a markedly lower inhibitory effect on the reverse transcriptase activity than on the DNA-dependent DNA polymerase activity. This was in analogy with earlier findings with 3'-azido-2',3'-dideoxythymidine 5'-triphosphate. Among the tested pyrophosphate analogs only phosphonoformate was inhibitory.

Inhibition of human and duck hepatitis B virus by 2',3'-dideoxy-3'-fluoroguanosine in vitro.

The fluorinated guanosine analog 2',3'-dideoxy-3'-fluoroguanosine (FLG) has been shown to have an effect on duck hepatitis B virus (DHBV) in vivo and in vitro. In this study the inhibitory effect of FLG on DHBV and human hepatitis B virus (HBV) was evaluated in vitro. Cell lines transfected either with DHBV or HBV DNA and primary duck hepatocyte cell cultures were used. Virus production was analysed by PCR and a quantitative PCR was established for DHBV for determination of the inhibitory concentrations of the drug. 50% inhibition was achieved with an FLG concentration of 0.2 microg/ml (0.7 microM) and 90% inhibition was observed with an FLG concentration of 1.0 microg/ml (3.7 microM) using the DHBV transfected cell line. FLG showed an effect on DHBV production in primary duck hepatocyte cell cultures at concentrations down to 0.1 microg/ml (0.4 microM). However, the DHBV production returned to pre-treatment levels within a few days after cessation of treatment. HBV production in transfected cell lines was also inhibited by FLG. Both DHBV and HBV DNA-polymerases were inhibited by FLG triphosphate and 50% inhibition was observed at a concentration of 0.05 microg/ml (0.1 microM) for DHBV and 0.03 microg/ml (0.05 microM) for HBV. FLG is an efficient inhibitor of DHBV replication both in vivo and in vitro and of HBV in vitro which makes it a good candidate for treatment of HBV infections. However, it does not completely eliminate the virus since a relapse in virus production was observed when treatment was withdrawn. Therefore it would be interesting to evaluate FLG in combination with other types of anti-HBV drugs.

Responses to rubella, tetanus, and diphtheria vaccines in otitis-prone and non-otitis-prone children.

Delayed immunologic maturation--among other things based on a selective lack of antibodies against some acute purulent otitis media (AOM)-associated pneumococcal types--has been proposed in children with recurrent AOM (rAOM). To further elucidate the immunologic response in these children, we compared the antibody responses to diphtheria, tetanus, and rubella vaccinations in 13 children with rAOM and 29 children without AOM. The children took part in a prospective study from birth to the age of 3 years. The antibody response to the rubella vaccine was significantly lower in the children with rAOM. The responses to tetanus and to diphtheria did not differ between children with and without rAOM. Thus, the results indicate that in addition to the known lack of antibodies against pneumococcal polysaccharide antigens, a lower antibody response against at least one protein antigen may exist in otitis-prone children.

In-patient rehabilitation after stroke: outcome and factors associated with improvement.

A study aimed at examining the outcome of activities of daily living (ADL) of patients undergoing geriatric stroke rehabilitation was performed. Background and admission data of 99 patients surviving the acute phase and needing further hospital rehabilitation were registered. Forty per cent of the patients improved their ADL ability. The logistic regression modelling with the dichotomous dependent variable improvement versus no improvement showed the following factors associated with improvement: a diagnosis of intracerebral haemorrhage, male sex, high postural stability score at the admission and cohabitation. In conclusion, the most severely affected stroke patients, especially patients with intracerebral haemorrhage, have a great potential for improving their ADL. The results of the logistic regression model can serve as a useful guide when it comes to identifying patients that stand a fair chance of improving during their rehabilitation stay. Equally important, patients with a poor rehabilitation prognosis who may need intensified rehabilitation efforts to achieve optimum improvement can now be identified.

Serum antibodies against respiratory tract viruses in episodes of acute otitis media.

Although the findings of epidemiological studies have suggested viral respiratory tract infection (RTI) to be crucially involved in the development of acute otitis media (AOM), the relationship between AOM and viral RTI remains unclear. Serum samples, obtained in the acute and convalescent phases of 57 AOM episodes (in 35 children during the first three years of life) were analysed for IgG antibodies against influenza A viruses, influenza B viruses, parainfluenza virus type 1, respiratory syncytial virus and adenoviruses. One third of the AOM episodes (18/57) could be related to viral RTI, as evidenced by significant increases in viral serum antibody activity. Treatment failure occurred in four AOM episodes where increases in serum viral antibody activity were noted. In three of these failures, antibiotic treatment was unsuccessful despite the bacterial strains not being resistant to the drug used. This suggests that concomitant viral infection may be a determinant of treatment outcome in some AOM episodes.

Serum antibodies against respiratory tract viruses: a prospective three-year follow-up from birth.

Acute otitis media (AOM) has been epidemiologically related to viral respiratory tract infections, and viral antigens have also been detected in middle ear secretion in some AOM episodes. Successive serum samples from children followed prospectively for three years from birth were analysed for IgG antibodies against respiratory syncytial virus (RSV), adenoviruses and influenza A virus. Values from serum antibody activity gradually decreased during the first six months of life, followed by a gradual increase. Various relationships were found to obtain between age and the increases of antibody activity against the different viruses. Thus, three quarters of those tested had manifested increased antibody activity against RSV by 18 months of age, and against adenoviruses by 30 months of age. No increase of antibody activity against influenza A was noted before 12 months of age, and then only seen in two thirds of those tested during the entire three-year observation period. With regard to age, however, the proportion of children with increased antibody activity to RSV, adenoviruses or influenza A virus did not differ between otitis-prone and non-otitis-prone children. Thus, as compared to non-otitis-prone children, development of the ability to produce antibodies against these viruses was not found to be delayed in otitis-prone children.