50% duty cycle may be inappropriate to achieve a sufficient chest compression depth when cardiopulmonary resuscitation is performed by female or light rescuers

Rescuers' characteristics associated with the correct chest compression during cardiopulmonary resuscitation

AIM

To analyse the caregivers' physical, anthropometrical and educational characteristics associated with adequate chest compression and full chest recoil during cardiopulmonary resuscitation (CPR).

METHODS

An observational prospective research study was conducted. Emergency and critical care health professionals and students performed two minutes of chest compressions on a dummy. Depth and residual leaning after the compressions were assessed and their association with several variables (physical, anthropometrical, and educational) was analysed using logistic regression models.

RESULTS

Two hundred thirty-eight volunteers participated. Previous experience of the rescuer in less than six CPRs (OR = 3.03; 95% CI 1.2-7.63) was related to a higher probability of not achieving an adequate depth of compressions. Greater height (OR: .93; 95% CI .87-.99) and grip strength (OR: .94; 95% CI .89-.99) were associated with correct performance of chest compression. We did not find any characteristic related to chest recoil.

CONCLUSIONS

The caregiver's previous experience with CPR was the strongest factor associated with adequate performance of chest compressions. To a lesser extent, the professional's height and upper body muscle strength also have an influence. No factors associated with the adequacy of full chest recoil were identified.

Can a Glove-Coach Technology Significantly Increase the Efficacy of Cardiopulmonary Resuscitation on Non-healthcare Professionals? A Controlled Trial

Introduction: Cardiovascular accidents are the world's leading cause of death. A good quality cardiopulmonary resuscitation (CPR) can reduce cardiac arrest-associated mortality. This study aims to test the coaching system of a wearable glove, providing instructions during out-of-hospital CPR. Materials and Methods: We performed a single-blind, controlled trial to test non-healthcare professionals during a simulated CPR performed on an electronic mannequin. The no-glove group was the control. The primary outcome was to compare the accuracy of depth and frequency of two simulated CPR sessions. Secondary outcomes were to compare the decay of CPR performance and the percentage of the duration of accurate CPR. Results: About 130 volunteers were allocated to 1:1 ratio in both groups; mean age was 36 ± 15 years (min-max 21-64) and 62 (48%) were men; 600 chest compressions were performed, and 571 chest compressions were analyzed. The mean frequency in the glove group was 117.67 vs. 103.02 rpm in the control group (p < 0.001). The appropriate rate cycle was 92.4% in the glove group vs. 71% in the control group, with a difference of 21.4% (p < 0.001). Mean compression depth in the glove group was 52.11 vs. 55.17 mm in the control group (p < 0.001). A mean reduction of compression depth over time of 5.3 mm/min was observed in the control group vs. 0.83 mm/min of reduction in the glove group. Conclusion: Visual and acoustic feedbacks provided through the utilization of the glove's coaching system were useful for non-healthcare professionals' CPR performance.

Rescuers' characteristics associated with the correct chest compression during cardiopulmonary resuscitation

AIM

To analyse the caregivers' physical, anthropometrical and educational characteristics associated with adequate chest compression and full chest recoil during cardiopulmonary resuscitation (CPR).

METHODS

An observational prospective research study was conducted. Emergency and critical care health professionals and students performed two minutes of chest compressions on a dummy. Depth and residual leaning after the compressions were assessed and their association with several variables (physical, anthropometrical, and educational) was analysed using logistic regression models.

RESULTS

Two hundred thirty-eight volunteers participated. Previous experience of the rescuer in less than six CPRs (OR: 3.03; CI 95%: 1.2-7.63) was related to a higher probability of not achieving an adequate depth of compressions. Greater height (OR: .93; 95% CI: .87-.99) and grip strength (OR: .94; 95% CI: .89-.99) were associated with correct performance of chest compression. We did not find any characteristic related to chest recoil.

CONCLUSIONS

The caregiver's previous experience with CPR was the strongest factor associated with adequate performance of chest compressions. To a lesser extent, the professional's height and upper body muscle strength also have an influence. No factors associated with the adequacy of full chest recoil were identified.

Comparison of chest compression quality in walking versus straddling cardiopulmonary resuscitation during stretcher transportation: A prospective randomised crossover study using manikins

The optimal strategy to ensure chest compression quality for patients being transported on a stretcher has not been established yet. We hypothesised that straddling cardiopulmonary resuscitation may improve chest compression quality in patients being transported on stretchers. We conducted a prospective randomised crossover study using manikins to investigate whether straddling cardiopulmonary resuscitation improves chest compression quality (depth, recoil, rate, correct hand position) performed on patients during stretcher transportation compared to walking cardiopulmonary resuscitation. Walking and straddling cardiopulmonary resuscitation were performed for 2 minutes each. The mean chest compression depth (mm) for 2 minutes was significantly greater in the straddling cardiopulmonary resuscitation group than in the walking cardiopulmonary resuscitation group (median, 51.3 [interquartile range, 46.7–55.5] versus 40.9 [34.6–50.1], P = 0.003). An adequate depth of chest compressions could not be achieved when walking cardiopulmonary resuscitation was performed by female participants, but the depth of chest compressions was within the acceptable range when female participants performed straddling cardiopulmonary resuscitation. On the other hand, the degree of deterioration was relatively small in male participants, even when they performed walking cardiopulmonary resuscitation. In patients with cardiac arrest being transported on a stretcher, straddling cardiopulmonary resuscitation improved the depth of chest compressions compared to walking cardiopulmonary resuscitation. Female rescuers, in particular, may consider using straddling cardiopulmonary resuscitation.

Effect of compression waveform and resuscitation duration on blood flow and pressure in swine: One waveform does not optimally serve

BACKGROUND

Chest compression (CC) research primarily focuses on finding the 'optimum' compression waveform using a variety of compression efficacy metrics. Blood flow is rarely measured systematically with high fidelity. Using a programmable mechanical chest compression device, we studied the effect of inter-compression pauses in a swine model of cardiac arrest, testing the hypothesis that a single 'optimal' CC waveform exists based on measurements of resulting blood flow.

METHODS

Hemodynamics were studied in 9 domestic swine (∼30 kg) using multiple flow probes and standard physiological monitoring. After 10 min of ventricular fibrillation, five mechanical chest compression waveforms (5.1 cm, varying inter-compression pauses) were delivered for 2 min each in a semi-random pattern, totaling 50 compression minutes. Linear Mixed Models were used to estimate the effect of compression waveform on hemodynamics.

RESULTS

Blood flow and pressure decayed significantly with time in both arteries and veins. No waveform maximized blood flow in all vessels simultaneously and the waveform generating maximal blood flow in a specific vessel changed over time in all vessels. A flow mismatch between paired arteries and veins, e.g. abdominal aorta and inferior vena cava, also developed over time. The waveform with the slowest rate and shortest duty cycle had the smallest mismatch between flows after about 30 min of CPR.

CONCLUSIONS

This data challenges the concept of a single optimal CC waveform. Time dependent physiological response to compressions and no single compression waveform optimizing flow in all vessels indicate that current descriptions of CPR don't reflect patient physiology.

CPR feedback/prompt device improves the quality of hands-only CPR performed in manikin by laypersons following the 2015 AHA guidelines

PURPOSE

We investigated the effects of a cardiopulmonary resuscitation (CPR) feedback/prompt device on the quality of chest compression (CC) during hands-only CPR following the 2015 AHA guidelines.

METHODS

A total of 124 laypersons were randomly assigned into three groups. The first (n=42) followed the 2010 guidelines, the second (n=42) followed the 2015 guidelines with no feedback/prompt device, the third (n=40) followed the 2015 guidelines with a feedback/prompt device (2015F). Participants underwent manual CPR training and took a written basic life support examination, then required to perform 2min of hands-only CPR monitored by a CPR feedback/prompt device. The quality of CPR was quantified as the percentage of correct CCs (mean CC depth and rate, complete recoil and chest compression fraction (CCF)) per 20s, as recorded by the CPR feedback/prompt device.

RESULTS

Significantly higher correct ratios of CC, CC depth, and rate were achieved in the 2010 group in each minute vs the 2015 group. The greater mean CC depth and rate were observed in the 2015F group vs the 2015 group. The correct ratio of CC was significantly higher in the 2015F group vs the 2015 group. CCF was also significantly higher in the 2015F group vs the 2015 group in the last 20s of CPR.

CONCLUSIONS

It is difficult for a large percentage of laypersons to achieve the targets of CC depth and rate following the 2015 AHA guidelines. CPR feedback/prompt devices significantly improve the quality of hands-only CPR performance by laypersons following the standards of the 2015 AHA guidelines.

Quantitative analysis of duty cycle in pediatric and adolescent in-hospital cardiac arrest

AIMS

Quality cardiopulmonary resuscitation (CPR) is associated with improved outcomes during cardiac arrest. Duty cycle (DC) represents an understudied element of CPR quality. Our objective was to quantitatively analyze DC during actual pediatric and adolescent in-hospital cardiac arrest (IHCA).

METHODS

Prospective observational study of IHCA at a large academic children's hospital. CPR variables included DC (%) up to the first 10min of recorded chest compressions (CCs). American Heart Association (AHA) DC compliance was prospectively defined as an average event DC of 50±5%. Percentage of events compliant with AHA DC was compared to a priori hypothesized compliance percentage of 25% using chi-square. Association between DC quartiles and categories of depth (<38, 38-49, ≥50mm) and rate (<100, 100-120, >120min(-1)) were analyzed by chi-square test for trend.

RESULTS

Between October 2006 and June 2015, 97 events in 87 patients were analyzed. Mean DC for events was 40±2.8%. DC quartiles: Q1 (DC ≤38.3%), Q2 (>38.3-40.1%), Q3 (>40.1-42.1%), Q4 (>42.1%). Only 5 (5.2%) events met AHA DC compliance, significantly less than the a priori hypothesis of 25% (p<0.001). Average CC rates trended higher across DC quartiles: (Q1) 105±9; (Q2) 106±9; (Q3) 112±8; and (Q4) 118±14min(-1); p<0.001. Other CPR quality variables were not associated with DC. There was no association between DC and survival.

CONCLUSIONS

Compression DC during resuscitation of actual child and adolescent IHCA met AHA recommendations in only 5% of events. In this series we found no association of DC with CC depth or survival.

Effect of the rate of chest compression familiarised in previous training on the depth of chest compression during metronome-guided cardiopulmonary resuscitation: a randomised crossover trial

OBJECTIVES

To assess how the quality of metronome-guided cardiopulmonary resuscitation (CPR) was affected by the chest compression rate familiarised by training before the performance and to determine a possible mechanism for any effect shown.

DESIGN

Prospective crossover trial of a simulated, one-person, chest-compression-only CPR.

SETTING

Participants were recruited from a medical school and two paramedic schools of South Korea.

PARTICIPANTS

42 senior students of a medical school and two paramedic schools were enrolled but five dropped out due to physical restraints.

INTERVENTION

Senior medical and paramedic students performed 1 min of metronome-guided CPR with chest compressions only at a speed of 120 compressions/min after training for chest compression with three different rates (100, 120 and 140 compressions/min). Friedman's test was used to compare average compression depths based on the different rates used during training.

RESULTS

Average compression depths were significantly different according to the rate used in training (p<0.001). A post hoc analysis showed that average compression depths were significantly different between trials after training at a speed of 100 compressions/min and those at speeds of 120 and 140 compressions/min (both p<0.001).

CONCLUSIONS

The depth of chest compression during metronome-guided CPR is affected by the relative difference between the rate of metronome guidance and the chest compression rate practised in previous training.

The suprasternal notch as a landmark of chest compression depth in CPR

OBJECTIVE

This study was performed to determine a landmark for chest compression depth for adult cardiopulmonary resuscitation (CPR) using chest computed tomography and to evaluate the validity of the landmark.

METHODS

The external anteroposterior diameters (EAPDs) of each chest at the suprasternal notch (SN) and the lower half (LH) of the sternum were measured. We analyzed the differences in the EAPDs between the LH and the SN in each EAPD group in the LH of the sternum as follows: less than 20.00, 20.00 to 21.99, 22.00 to 23.99, greater than or equal to 24.00. We compared the differences in the EAPDs between the 2 points with 50 mm and the chest compression depth on simulated one-fourth external chest compressions for each EAPD group on the LH of the sternum.

RESULTS

The mean difference in the EAPDs between the SN and the LH was 5.16 ± 0.91 mm. The differences in the EAPDs between the SN and the LH of the sternum with 50 mm did not indicate a significant difference. The mean one-fourth EAPD at the LH of the sternum was 5.50 ± 0.53 mm. There was not a significant difference in the residual chest depth on one-fourth simulated chest compression for each EAPD group on the LH of the sternum.

CONCLUSIONS

The SN may have value as a functional landmark for chest compression depth in adult CPR. Our findings combined with the simulated one-fourth chest compressions were more consistent with the depth between 50 and 60 mm recommended by the 2015 CPR guidelines.

The uniform chest compression depth of 50 mm or greater recommended by current guidelines is not appropriate for all adults

OBJECTIVE

This study was conducted to evaluate the appropriateness of the chest compression (CC) depth recommended in the current guidelines and simulated external CCs, and to characterize the optimal CC depth for an adult by body mass index (BMI).

METHODS

Adult patients who underwent chest computed tomography as a screening test for latent pulmonary diseases in the health care center were enrolled in this study. We calculated the internal anteroposterior (AP) diameter (IAPD) and external AP diameter (EAPD) of the chest across BMIs (<18.50, 18.50-24.99, 25.00-29.99, and ≥30.00 kg/m(2)) for simulated CC depth. We also calculated the residual chest depths less than 20 mm for simulated CC depth.

RESULTS

There was a statistically significant difference in the chest EAPD and IAPD measured at the lower half of the sternum for each BMI groups (EAPD: R(2) = 0.638, P < .001; IAPD: R(2) = 0.297, P < .001). For one-half external AP CC, 100% of the patients, regardless of BMI, had a calculated residual internal chest depth less than 20 mm. For one-fourth external AP CC, no patients had a calculated residual internal chest depth less than 20 mm. For one-third external AP CC, only 6.48% of the patients had a calculated residual internal chest depth less than 20 mm.

CONCLUSIONS

It is not appropriate that the current CC depth (≥50 mm), expressed only as absolute measurement without a fraction of the depth of the chest, is applied uniformly in all adults. In addition, in terms of safety and efficacy, simulated CC targeting approximately between one-third and one-fourth EAPD CC depth might be appropriate.