Does Dual Operator CPR help minimize interruptions in chest compressions?

Aims

Basic Life Support Guidelines 2005 emphasise the importance of reducing interruptions in chest compressions (no-flow duration) yet at the same time stopped recommending Dual Operator CPR. Dual Operator CPR (where one rescuer does ventilations and one chest compressions) could potentially minimize no-flow duration compared to Single Operator CPR. This study aims to determine if Dual Operator CPR reduces no-flow duration compared to Single Operator CPR.

Methodology

This was a prospective randomised controlled crossover trial. Medical students were randomised into ‘Dual Operator’ or ‘Single Operator’ CPR groups. Both groups performed 4 min of CPR according to their group allocation on a resuscitation manikin before crossing over to perform the other technique one week later.

Results

Fifty participants were recruited. Dual Operator CPR achieved slightly lower no-flow durations than the Single Operator CPR (28.5% (S.D. = 3.7) versus 31.6% (S.D. = 3.6), P ≤ 0.001). Dual Operator CPR was associated with slightly more rescue breaths per minute (4.9 (S.D. = 0.5) versus 4.5 (S.D. = 0.5), P = 0.009. There was no difference in compression depth, compression rate, duty cycle, rescue breath flow rate or rescue breath volume.

Conclusions

Dual Operator CPR with a compression to ventilation rate of 30:2 provides marginal improvement in no-flow duration but CPR quality is otherwise equivalent to Single Operator CPR. There seems little advantage to adding teaching on Dual Operator CPR to lay/trained first responder CPR programs.     

Do manual chest compressions provide substantial ventilation during prehospital cardiopulmonary resuscitation?

IntroductionChest compressions have been suggested to provide passive ventilation during cardiopulmonary resuscitation. Measurements of this passive ventilatory mechanism have only been performed upon arrival of out-of-hospital cardiac arrest patients in the emergency department. Lung and thoracic characteristics rapidly change following cardiac arrest, possibly limiting the effectiveness of this mechanism after prolonged resuscitation efforts. Goal of this study was to quantify passive inspiratory tidal volumes generated by manual chest compression during prehospital cardiopulmonary resuscitation.Materials and methodsA flowsensor was used during adult out-of-hospital cardiac arrest cases attended by a prehospital medical team. Adult, endotracheally intubated, non-traumatic cardiac arrest patients were eligible for inclusion. Immediately following intubation, the sensor was connected to the endotracheal tube. The passive inspiratory tidal volumes generated by the first thirty manual chest compressions performed following intubation (without simultaneous manual ventilation) were calculated.Results10 patients (5 female) were included, median age was 64 years (IQR 56, 77 years). The median compression frequency was 111 compression per minute (IQR 107, 116 compressions per minute). The median compression depth was 5.6 cm (IQR 5.4 cm, 6.1 cm). The median inspiratory tidal volume generated by manual chest compressions was 20 mL (IQR 13, 28 mL).ConclusionUsing a flowsensor, passive inspiratory tidal volumes generated by manual chest compressions during prehospital cardiopulmonary resuscitation, were quantified. Chest compressions alone appear unable to provide adequate alveolar ventilation during prehospital treatment of cardiac arrest.     

Public-access defibrillation: Where do we place the aeds?

Background. Many prehospital cardiac arrests occur in public places. Even the best EMS systems have a finite response time. Therefore, it has been recommended that automated external defibrillators (AEDs) be placed in public areas for immediate access by trained members of the general public. Objective. To determine the locations of multiple cardiac arrests in order to plan for placement of public-access AEDs. Methods. Retrospective review of all primary cardiac arrests in calendar year 1997. Cardiac arrests in which resuscitation was not attempted (DOA), traumatic cases, pediatric cases, and those due to “other” causes were excluded. Location of the cardiac arrest was obtained from the ambulance run ticket. The EMS system is an urban, Midwestern, all-ALS, public-utility model system with fire department first re-sponders that transports approximately 58,000 patients annually. Results. There was scene response to 922 cardiac arrests. 377 DOAs and 219 nonprimary cardiac arrests were excluded. There were 326 primary cardiac arrests. Sixteen locations had more than one cardiac arrest: ll locations had two cardiac arrests, four locations had three cardiac arrests, and one location had four cardiac arrests. The airport, an airline overhaul facility, a casino, and two hotels each had two cardiac arrests; the other Iocations of multiple cardiac arrests were in nursing homes. The Professional sports stadiums had no cardiac arrests. Conclusions. Since very few locations had more than one cardiac arrest, it may be difficult to identify high-yield public places in which to place an AED. Nursing homes may want to consider AED availability.     

Can thoracic impedance monitor the depth of chest compressions during out-of-hospital cardiopulmonary resuscitation?

Aim

To analyze the relationship between the depth of the chest compressions and the fluctuation caused in the thoracic impedance (TI) signal in out-of-hospital cardiac arrest (OHCA). The ultimate goal was to evaluate whether it is possible to identify compressions with inadequate depth using information of the TI waveform.

Methods

60 OHCA episodes were extracted, one per patient, containing both compression depth (CD) and TI signals. Every 5 s the mean value of the maxima of the CD, D_max, and three features characterizing the fluctuations caused by the compressions in the TI waveform (peak-to-peak amplitude, area and curve length) were computed. The linear relationship between D_max and the TI features was tested using Pearson correlation coefficient (r) and univariate linear regression for the whole population, for each patient independently, and for series of compressions provided by a single rescuer. The power of the three TI features to classify each 5 s-epoch as shallow/non-shallow was evaluated in terms of area under the curve, sensitivity and specificity.

Results

The r was 0.34, 0.36 and 0.37 for peak-to-peak amplitude, area and curve length respectively when the whole population was analyzed. Within patients the median r was 0.40, 0.43 and 0.47, respectively. The analysis of the series of compressions yielded a median r of 0.81 between D_max and the peak-to-peak amplitude, but it decreased to 0.47 when all the series were considered jointly. The classifier based on the TI features showed 90.0%/37.1% and 86.2%/43.5% sensitivity/specificity values, and an area under the curve of 0.75 and 0.71 for the training and test set respectively.

Conclusion

Low linearity between CD and TI was noted in OHCA episodes involving multiple rescuers. Our findings suggest that TI is unreliable as a predictor of D_max and inaccurate in detecting shallow compressions.     

Why do women choose nursing?

To answer the question, "Why do women choose nursing?", female nursing students were given an opportunity to speak "in their own voices" to reveal their needs, motivations, and expectations. In a study employing grounded theory methodology, 16 female nursing students were interviewed and audiotaped for initial constant comparison analysis. Further analyses employing coding, categorizing, comparing, and contrasting of data made it possible to isolate recurrent words and phrases, and to identify concepts for the purpose of theory building. Reliability was established by both stability analysis and reproducibility analysis. Validity was supported by construct (convergent and discriminant) and representational components. Not surprisingly, the construct of desiring to care for others was readily apparent. However, it was power and empowerment that emerged from the interviews as the most resounding and fully developed construct of the study. Students' references to practical motivations for choosing nursing were so notably scarce that their virtual omission constituted an important theme.