Acute muscle fatigue and CPR quality assisted by visual feedback devices: A randomized-crossover simulation trial

An effort to reduce chest compression pauses during automated external defibrillator use among laypeople: A randomized partially blinded controlled trial

Aim

To implement small methodological changes in basic life support (BLS) training to reduce unnecessary pauses during automated external defibrillator (AED) use.

Methods

One hundred and two university students with no BLS knowledge were randomly allocated into three groups (control and 2 experimental groups). Both experimental groups received a two-hour BLS training. While the contents were identical in both groups, in one of them the reduction of no-flow time was focused on (focused no-flow group). The control group did not receive any training. Finally, all of them were evaluated in the same out-of-hospital cardiac arrest simulated scenario. The primary endpoint was the compression fraction.

Results

Results from 78 participants were analysed (control group: 19; traditional group: 30; focused no-flow group: 29). The focused no-flow group achieved higher percentages of compression fraction (median: 56.0, interquartile rank (IQR): 53.5-58.5) than the traditional group (44.0, IQR: 42.0-47.0) and control group (52.0, IQR: 43.0-58.0) in the complete scenario. Participants from the control group performed compression-only cardiopulmonary resuscitation (CPR), while the other groups performed compression-ventilation CPR. CPR fraction was calculated, showing the fraction of time in which the participants were performing resuscitation manoeuvres. In this case, the focused no-flow group reached higher percentages of CPR fraction (77.6, IQR: 74.4-82.4) than the traditional group (61.9, IQR: 59.3-68.1) and the control group (52.0, IQR: 43.0-58.0).

Conclusions

Laypeople having automated external defibrillation training focused on acting in anticipation of the AED prompts contributed to a reduction in chest compression pauses during an OHCA simulated scenario.

Temporal analysis of continuous chest compression rate and depth performed by firefighters during out of hospital cardiac arrest

BACKGROUND

Quality of chest compressions (CC) during cardiopulmonary resuscitation (CPR) often do not meet guideline recommendations for rate and depth. This may be due to the fatiguing nature of physically compressing a patient's chest, meaning that CPR quality reduces over time.

OBJECTIVE

This analysis investigates the effect of CPR duration on the performance of continuous CCs delivered by firefighters equipped with CPR feedback devices.

METHODS

Data were collected from a first responder group which used CPR feedback and automatic external defibrillator devices when attending out-of-hospital cardiac arrest events. Depth and rate of CC were analysed for 134 patients. Mean CC depth and rate were calculated every 5 s during two-minute episodes of CPR. Regression models were created to evaluate the relationship between applied CC depth and rate as a function of time.

RESULTS

Mean (SD) CC depth during the investigation was 48 (9) mm. An inverse relationship was observed between CC depth and CPR duration, where CC depth decreased by 3.39 mm, over two-minutes of CPR (p < 0.001). Mean (SD) CC rate was 112.06 (5.87) compressions per minute. No significant relationship was observed between CC rate and CPR duration (p = 0.077). Mean depth was within guideline range for 33.58% of patient events, while guideline rate was observed in 92.54% of cases.

CONCLUSIONS

A reduction in CC depth was observed during two-minutes of continuous CCs while CC rate was not affected. One third of patients received a mean CC depth within guideline range (50 to 60 mm).

Association of Training in Basic Life Support with the Evolution of Cardiopulmonary Resuscitation Performed by Firefighters

Introduction

This study aimed to compare the results of professional technical and anthropometric anamnesis data with the transmission of external chest compressions performed by military firefighters at different execution times.

Objective

The objective was to evaluate the performance and perceived effort of the sequence of external chest compressions performed in two minutes, as well as the evolution of the technique over time.

Materials and Methods

This was a descriptive, correlational study involving adult firefighters who were members of a specific firefighter group, comprising a population of 105 individuals with a voluntary sample of 44 participants. The study used a Bayesian statistical approach to provide probabilistic expressions.

Results

The participants had an average work experience of 17 years, an average age of 38.6 years, an average weight of 81.48 kilograms, an average height of 176 centimeters, and an average of 2.5 qualifications. The results indicated that the firefighters performed external chest compressions with excellent technique and a moderate level of perceived effort in a two-minute evaluation. The evaluation of the evolution of the technique over time showed that the participants were able to maintain high-quality compressions for an average of 6 minutes, with a maximum of 20 uninterrupted minutes.

Conclusion

The study underscores the critical role of professional firefighters in performing and maintaining high-quality external chest compressions, which has the potential to reduce morbidity and mortality in cases of cardiorespiratory arrest.

Methodical approaches to determine the rate of radial muscle displacement using tensiomyography: A scoping review and new reporting guideline

Tensiomyography is a non-invasive method to assess skeletal muscle contractile properties from the stimulated radial displacement. Many studies have used the rate of displacement (Vc) as an indirect measure of muscle contraction velocity. However, no standardised methodical approach exists to measure displacement and determine Vc. This review aimed to provide an overview of concepts to determine Vc and measurement protocols to foster the development of a standardised methodical approach. This review followed the Preferred Reporting Items for Systematic Reviews and meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guideline. Systematic searches were performed within five electronic databases and additional sources. The included 62 studies reported 10 different concepts to determine Vc, which we summarised in three groups. The determination concepts differed mainly regarding time intervals during the contraction phase considered and criteria used to define these intervals. Essential information on the equipment and raters, measurement setup, electrical stimulation procedure, and data analysis were frequently not reported. In conclusion, no consensus on how to determine Vc existed. Incomplete reporting of measurement protocols hindered study comparison, which obstructs developing a standardised approach. Therefore, we propose a new guideline for reporting measurement protocols, which covers the 1) equipment and rater, 2) measurement setup, including positioning of the subject, sensor and electrodes, 3) electrical stimulation, including initial stimulation amplitude, increment, and endpoint, and 4) data analysis, including selection criteria and number of analysed signals and a definition of derived parameters.

How effective are chest compressions when wearing mask? A randomised simulation study among first-year health care students during the COVID-19 pandemic

Background

The resuscitation guidelines provided for the COVID-19 pandemic strongly recommended wearing personal protective equipment. The current study aimed to evaluate and compare the effectiveness of chest compressions and the level of fatigue while wearing two different types of mask (surgical vs. cloth).

Methods

A randomized, non-inferiority, simulation study was conducted. Participants were randomised into two groups: surgical mask group (n = 108) and cloth mask group (n = 108). The effectiveness (depth and rate) of chest compressions was measured within a 2-min continuous chest-compression-only CPR session. Data were collected through an AMBU CPR Software, a questionnaire, recording vital parameters, and using Borg-scale related to fatigue (before and after the simulation). For further analysis the 2-min session was segmented into 30-s intervals.

Results

Two hundred sixteen first-year health care students participated in our study. No significant difference was measured between the surgical mask and cloth mask groups in chest compression depth (44.49 ± 10.03 mm vs. 45.77 ± 10.77 mm), rate (113.34 ± 17.76/min vs. 111.23 ± 17.51/min), and the level of fatigue (5.72 ± 1.69 vs. 5.56 ± 1.67) (p > 0.05 in every cases). Significant decrease was found in chest compression depth between the first 30-s interval and the second, third, and fourth intervals (p < 0.01).

Conclusion

The effectiveness of chest compressions (depth and rate) was non-inferior when wearing cloth mask compared to wearing surgical mask. However, the effectiveness of chest compressions decreased significantly in both groups during the 2-min chest-compression-only CPR session and did not reach the appropriate chest compression depth range recommended by the ERC.

Can hospital adult code-teams and individual members perform high-quality CPR? A multicenter simulation-based study incorporating an educational intervention with CPR feedback

Aims

A multicenter simulation-based research study to assess the ability of interprofessional code-teams and individual members to perform high-quality CPR (HQ-CPR) at baseline and following an educational intervention with a CPR feedback device.

Methods

Five centers recruited ten interprofessional teams of AHA-certified adult code-team members with a goal of 200 participants. Baseline testing of chest compression (CC) quality was measured for all individuals. Teams participated in a baseline simulated cardiac arrest (SCA) where CC quality, chest compression fraction (CCF), and peri-shock pauses were recorded. Teams participated in a standardized HQ-CPR and abbreviated TeamSTEPPS® didactic, then engaged in deliberate practice with a CPR feedback device. Individuals were assessed to determine if they could achieve ≥80% combined rate and depth within 2020 AHA guidelines. Teams completed a second SCA and CPR metrics were recorded. Feedback was disabled for assessments except at one site where real-time CPR feedback was the institutional standard. Linear regression models were used to test for site effect and paired t-tests to evaluate significant score changes. Logistic univariate regression models were used to explore characteristics associated with the individual achieving competency.

Results

Data from 184 individuals and 45 teams were analyzed. Baseline HQ-CPR mean score across all sites was 18.5% for individuals and 13.8% for teams. Post-intervention HQ-CPR mean score was 59.8% for individuals and 37.0% for teams. There was a statistically significant improvement in HQ-CPR mean scores of 41.3% (36.1, 46.5) for individuals and 23.2% (17.1, 29.3) for teams (p < 0.0001). CCF increased at 3 out of 5 sites and there was a mean 5-s reduction in peri-shock pauses (p < 0.0001). Characteristics with a statistically significant association were height (p = 0.01) and number of times performed CPR (p = 0.01).

Conclusion

Code-teams and individuals struggle to perform HQ-CPR but show improvement after deliberate practice with feedback as part of an educational intervention. Only one site that incorporated real-time CPR feedback devices routinely achieved ≥80% HQ-CPR.

Correlation between real-time heart rate and fatigue in chest compression providers during cardiopulmonary resuscitation: A simulation-based interventional study

BACKGROUND

The American Heart Association guidelines recommend switching chest compression providers at least every 2 min depending on their fatigue during cardiopulmonary resuscitation (CPR). Although the provider's heart rate is widely used as an objective indicator for detecting fatigue, the accuracy of this measure is debatable.

OBJECTIVES

This study was designed to determine whether real-time heart rate is a measure of fatigue in compression providers.

STUDY DESIGN

A simulation-based prospective interventional study including 110 participants.

METHODS

Participants performed chest compressions in pairs for four cycles using advanced cardiovascular life support simulation. Each participant's heart rate was measured using wearable healthcare devices, and qualitative variables regarding individual compressions were obtained from computerized devices. The primary outcome was correct depth of chest compressions. The main exposure was the change in heart rate, defined as the difference between the participant's heart rate during individual compressions and that before the simulation was initiated.

RESULTS

With a constant compression duration for one cycle, the overall accuracy of compression depth significantly decreased with increasing heart rate. Female participants displayed significantly decreased accuracy of compression depth with increasing heart rate (odds ratio [OR]: 0.97; 95% confidence interval [CI]: 0.95-0.98; P < .001). Conversely, male participants displayed significantly improved accuracy with increasing heart rate (OR: 1.03; 95% CI: 1.02-1.04; P < .001).

CONCLUSION

Increasing heart rate could reflect fatigue in providers performing chest compressions with a constant duration for one cycle. Thus, provider rotation should be considered according to objectively measured fatigue during CPR.

Comparison of the effects of shortening rest intervals on the quality of cardiopulmonary resuscitation, physiological parameters, and hemodynamic parameters in well-trained rescuers: Randomized simulation study

BACKGROUND

Cardiopulmonary resuscitation (CPR) performance depends on individual ability and training. Well-trained or professional rescuers can maintain high-quality CPR for longer than laypeople. This study aimed to examine the effects of reducing resting intervals on CPR performance, physiological parameters, and hemodynamic parameters during prolonged CPR in well-trained providers.

METHODS

The study enrolled 90 volunteers from the paramedic students of our institution. They were randomly divided into 3 groups: 2 minutes, 1 minute 45 seconds, and 1 minute 30 seconds rest groups. Each participant performed 5 cycles of chest compression only CPR (2 min/cycle) with different resting intervals according to grouping. CPR quality, physiological variations, and hemodynamic variations were measured for each cycle and compared across the groups.

RESULTS

Of the 90 volunteers, 79 well-trained providers were finally included. The variation of the average chest compression depth across the 5 cycles showed significant differences between the 3 groups: from cycle 1 to 2: 1.2 (3.1) mm, -0.8 (2.0) mm, and -2.0 (3.0) mm in the 2 minutes, 1 minute 45 seconds, and 1 minute 30 seconds groups, respectively (P < .001); from cycle 1 to 3: 0.0 (3.0) mm, -0.7 (3.2) mm, and -2.6 (3.9) mm, respectively (P = .030). However, all 3 groups maintained the recommended rate and chest compression depth for all 5 cycles. Physiological and hemodynamic parameters showed no significant differences between the groups.

CONCLUSIONS

Well-trained providers were able to maintain high-quality CPR despite reducing rest intervals. Adjusting the rest interval may help maintain overall CPR quality in special situations or where layperson rescuers are involved.

CPR by foot. An alternative in special circumstances? A randomized simulation study

OBJECTIVE

To assess the differences in the quality and self-perception of CPR performed with foot technique compared to the standard technique with the hands in nursing students.

METHODS

65 university nursing students participated in a randomized simulation crossover design study. The participants randomly performed two CPR tests: CPR by foot and CPR by hands techniques. The compression-only protocol with a 2-min test was used with the Resusci Anne QCPR® manikin and Wireless Skill Reporter® software, both from Laerdal.

RESULTS

Participants had lower quality when doing CPR by foot (72%) than when doing standard CPR (91%) (p = 0.006). 95% of the participants indicated standard CPR as the technique of choice, while 92% indicated that they would use CPR by foot if it was not possible to perform standard technique.

CONCLUSIONS

CPR quality was lower when performing foot technique, although with positive results. It would be advisable for people with acquired CPR skills to know that they can do foot compressions in situations where they cannot use their hands.

Workload of learners during simulated paediatric cardiopulmonary resuscitation

Introduction

Learner workload during simulated team-based resuscitations is not well understood. In this descriptive study, we measured the workload of learners in different team roles during simulated paediatric cardiopulmonary resuscitation.

Methods

Paediatric emergency nurses and paediatric and emergency medicine residents formed teams of four to eight and randomised into roles to participate in simulation-based, paediatric resuscitation. Participant workload was measured using the NASA Task Load Index, which provides an average workload score (from 0 to 100) across six subscores: mental demand, physical demand, temporal demand, performance, frustration and mental effort. Workload is considered low if less than 40, moderate if between 40 and 60 and high if greater than 60.

Results

There were 210 participants representing 40 simulation teams. 138 residents (66%) and 72 nurses (34%) participated. Team lead reported the highest workload at 65.2±10.0 (p=0.001), while the airway reported the lowest at 53.9±10.8 (p=0.001); team lead had higher scores for all subscores except physical demand. Team lead reported the highest mental demand (p<0.001), while airway reported the lowest. Cardiopulmonary resuscitation coach and first responder reported the highest physical demands (p<0.001), while team lead and nurse recorder reported the lowest (p<0.001).

Conclusions

Workload for learners in paediatric simulated resuscitation teams was moderate to high and varied significantly based on team role. Composition of workload varied significantly by team role. Measuring learner workload during simulated resuscitations allows improved processes and choreography to optimise workload distribution.

Physiological Response of Quality Cardiopulmonary Resuscitation, Crossover Trial on Mannequin in Extreme Temperature Conditions

BACKGROUND

To determine the relationship between physiological fatigue and the quality of cardiopulmonary resuscitation (CPR) in trained resuscitators in hostile thermal environments (extreme cold and heat) simulating the different conditions found in an out-of-hospital cardiorespiratory arrest.

METHODS

Prospective observational study involving 60 students of the health sciences with training in resuscitation, who simulated CPR on a mannequin for 10 min in different thermal environments: thermo-neutral environment (21 °C and 60% humidity), heat environment (41 °C and 98% humidity) and cold environment (-35 °C and 80% humidity). Physiological parameters (heart rate and lactic acid) and CPR quality were monitored.

RESULTS

We detected a significant increase in the number of compressions per minute in the "heat environment" group after three minutes and in the mean rate after one minute. We observed a negative correlation between the total number of compressions and mean rate with respect to mean depth. The fraction of compressions (proportion of time in which chest compressions are carried out) was significant over time and the mean rate was higher in the "heat environment". Physiological parameters revealed no differences in heart rate depending on the resuscitation scenario; however, there was a greater and faster increase in lactate in the "heat environment" (significant at minute 3). The total proportion of participants reaching metabolic fatigue was also higher in the "heat environment".

CONCLUSIONS

A warm climate modifies metabolic parameters, reducing the quality of the CPR maneuver.

Is Low-Frequency Electrical Stimulation a Tool for Recovery after a Water Rescue? A Cross-Over Study with Lifeguards

This study aimed to evaluate the degree to which transcutaneous electrical stimulation (ES) enhanced recovery following a simulated water rescue. Twenty-six lifeguards participated in this study. The rescue consisted of swimming 100 m with fins and rescue-tube: 50 m swim approach and 50 m tow-in a simulated victim. Blood lactate clearance, rated perceived effort (RPE), and muscle contractile properties were evaluated at baseline, after the water rescue, and after ES or passive-recovery control condition (PR) protocol. Tensiomiography, RPE, and blood lactate basal levels indicated equivalence between both groups. There was no change in tensiomiography from pre to post-recovery and no difference between recovery protocols. Overall-RPE, legs-RPE and arms-RPE after ES (mean ± SD; 2.7 ± 1.53, 2.65 ± 1.66, and 2.30 ± 1.84, respectively) were moderately lower than after PR (3.57 ± 2.4, 3.71 ± 2.43, and 3.29 ± 1.79, respectively) (p = 0.016, p = 0.010, p = 0.028, respectively). There was a significantly lower blood lactate level after recovery in ES than in PR (mean ± SD; 4.77 ± 1.86 mmol·L^-1 vs. 6.27 ± 3.69 mmol·L^-1; p = 0.045). Low-frequency ES immediately after a water rescue is an effective recovery strategy to clear out blood lactate concentration.

Measuring the physiological impact of extreme heat on lifeguards during cardiopulmonary resuscitation. Randomized simulation study

OBJECTIVE

Lifeguard teams carry out their work in extremely hot conditions in many parts of the world. The aim of this study was to analyze the impact of high temperatures on physiological parameters during cardiopulmonary resuscitation (CPR).

METHOD

A randomized quasi-experimental cross-over design was used to test physiological lifesaving demands (50 min acclimatization +10 min CPR) in two different thermal environments: Thermo-neutral environment (25 °C) vs Hyperthermic environment (37 °C).

RESULTS

The data obtained from 21 lifeguards were included, this covers a total of 420 min of resuscitation. The CPR performance was constantly maintained during the 10 min. The Oxygen uptake (VO 2) ranged from 17 to 18 ml/min/kg for chest compressions (CC) and between 13 and 14 ml/min/kg for ventilations (V) at both 25 °C and 37 °C, with no significant difference between environments (p > 0.05). The percentage of maximum heart rate (%HR max) increased between 7% and 8% at 37 °C (p < 0.001), ranging between 75% and 82% of HR max. The loss of body fluids (LBF) was higher in the hyperthermic environment; LBF: (37 °C: 400 ± 187 g vs 25 °C: 148 ± 81 g, p < 0.001). Body temperature was 1 °C higher at the end of the test (p < 0.001). The perceived fatigue (RPE) increased by 37° an average of 2 points on a scale of 10 (p = 0.001).

CONCLUSIONS

Extreme heat is not a limiting factor in CPR performance with two lifeguards. Metabolic consumption is sustained, with an increase in CC, so V can serve as active rest. Nevertheless, resuscitation at 37 °C results in a higher HR, is more exhausting and causes significant loss of fluids due to sweating.

Tensiomyographical responsiveness to peripheral fatigue in quadriceps femoris

Background

Fatigue influences athletic performance and can also increase the risk of injury in sports, and most of the methods to evaluate it require an additional voluntary effort. Tensiomyography (TMG), which uses electrical stimulation and a displacement sensor to evaluate muscle contraction properties of one or more muscle bellies, has emerged as a technique that can assess the presence of peripheral and central fatigue without requiring additional voluntary efforts. However, the evaluation of the TMG’s ability to detect fatigue is limited, both at the level of muscle bellies and statistical methods. Thus, the aim of the present study was twofold: (i) to examine and compare the tensiomyographical responsiveness to quadriceps femoris (QF) fatigue by multiple statistical methods and (ii) to analyze sex differences in the variation produced by fatigue in TMG parameters.

Methods

Thirty-nine recreational athletes participated (19 males/20 females; aged 22 ± 2 years). TMG parameters of QF bellies and maximal voluntary isometric contraction (MVIC) were measured before and after a fatigue protocol. TMG parameters used were maximum radial deformation (Dm), contraction time between 10–90% of the Dm (Tc), contraction velocity between 10–90% (Vc) and of the first 10% (V10) of the Dm. Internal responsiveness of TMG to fatigue was analyzed by paired t-test and standardized response mean (SRM). External responsiveness was examined by correlations, regression models, and receiver operating characteristic (ROC) curves.

Results

All TMG parameters, except for Tc of rectus femoris and vastus medialis, showed large internal responsiveness. In adjusted regression models by sex, only Dm and V10 of rectus femoris were statistically associated (p < 0.05) with b coefficients of 0.40 and 0.43, respectively. r2 explained the 22% of the total variance. In addition, these parameters could discriminate between QF with and without fatigue.

Conclusion

Since the QF is the main strength contributor during multiple physical activities, clinicians and trainers will be able to discriminate the presence of fatigue and the magnitude of changes in the QF strength by TMG evaluation.