Adequate Chest Compression Depth Research Articles

Effectiveness of innovative chest compression on the emergency department stretcher by an alternative method: a randomized controlled crossover trial

Comparison of the three methods standing-on-a-stool (SS), one knee kneeling on a stretcher (KS), and kneeling at the same height as the patient’s bed on the kneeling stool (KK) to evaluate the yielded of highest CPR quality and rescuer comfortability. A prospective randomized cross-over study which compares the three different rescuer positions for their effectiveness of chest compression. Conducted at a tertiary care between 19 and 22 Aug 2022. Emergency personnel aged 18 years or older, who completed the AHA-approved BLS course. The chest compression data was obtained by the ALIVE AED manikin® and AED reporting system. The information on the CPR quality and post-test questionnaires assessing the participants’ preference, satisfaction and modified Borg’s scale score was collected. The three methods shown no statistically significant difference in adequate chest compression depth (percentage). KK was not superior than SS at chest compression rate (P = 0.05). The adequate full chest recoil achieved with KK and KS were significantly higher than that of SS. However, there were no statistical difference between the three methods in the modified Borg’s scale score. Based on the satisfying score, the rescuers preferred KK to either SS (p 0.007) or KS (p 0.012). The three methods shown no statistically significant difference in adequate chest compression depth (percentage). Still, both KK and KS provided more adequate chest recoil, so we would recommend using these two methods in the ED.Clinical trial registry: This study was retrospective registration in thaiclinicaltrials.org (TCTR20230119002, 19/1/2023).

Comparisons of the vertical one-handed chest compressions according to the rescuer's handedness

ObjectiveThe vertical one-handed chest compression (OHCC) technique has demonstrated superior compression power and chest compression depth (CCD) compared to conventional OHCC. This study aimed to determine if a rescuer's handedness influences the CCD during the vertical OHCC. MethodsThis prospective randomized crossover simulation trial included 59 medical doctors. Each performed a 2-min single-rescuer cardiopulmonary resuscitation (CPR) on a pediatric manikin using the vertical OHCC, once with the dominant hand (Test 1) and once with the non-dominant hand (Test 2). CPR parameters were recorded in real-time via sensors in the manikin, and the compression force exerted by each hand was measured using a force plate. ResultsThe mean and adequate CCD did not differ significantly between Test 1 and 2 (mean depth: 52 mm (interquartile range [IQR]: 49–57) in Test 1 vs. 52 mm (IQR: 49–57) in Test 2, P = 0.625; adequate depth: 97% (IQR: 37–100) in Test 1 vs. 92% (IQR: 51–99) in Test 2, P = 0.619). The mean compression force was significantly greater in the dominant hand compared to the non-dominant hand (23.1 kg ± 4.9 in dominant hand vs. 21.7 kg ± 4.1 in non-dominant hand, P < 0.001). Other parameters showed no significant differences between Tests 1 and 2. ConclusionsWhile vertical OHCC with a dominant hand generated greater force, the rescuer's handedness did not affect the CCD during the vertical OHCC.

Efficacy of distance training program for cardiopulmonary resuscitation utilizing smartphone application and home delivery system

Aim of the studyCommunity cardiopulmonary resuscitation (CPR) education is important for laypersons. However, during the COVID-19 pandemic, with social distancing, conventional face-to-face CPR training was unavailable. We developed a distance learning CPR training course (HEROS-Remote) using a smartphone application that monitors real-time chest compression quality and a home delivery collection system for mannikins. This study aimed to evaluate the efficacy of the HEROS-Remote course by comparing chest compression quality with that of conventional CPR training. MethodsWe applied layperson CPR education with HEROS-Remote and conventional education in Seoul during the COVID-19 pandemic. Both groups underwent a 2-min post-training chest compression test, and we tested non-inferiority. Chest compression depth, rate, complete recoil, and composite chest compression score was measured. Trainees completed a satisfaction survey on CPR education and delivery. The primary outcome was the mean chest compression depth. ResultsA total of 180 trainees were enrolled, with 90 assigned to each training group. Chest compression depth of HEROS-Remote training showed non-inferiority to that of conventional training (67.4 vs. 67.8, p = 0.78), as well as composite chest compression score (92.7 vs. 95.5, p = 0.16). The proportions of adequate chest compression depth, chest compression rate, and chest compressions with complete chest recoil were similar in both training sessions. In the HEROS-Remote training, 90% of the trainees were satisfied with CPR training, and 96% were satisfied with the delivery and found it convenient. ConclusionHEROS-Remote training was non-inferior to conventional CPR training in terms of chest compression quality. Distance learning CPR training using a smartphone application and mannikin delivery had high user satisfaction and was logistically feasible.

Abstract 308: Efficacy Of Distance Learning For Cardiopulmonary Resuscitation Training Utilizing Smartphone App And Mannikin Delivery-collection System

Aim of the study: Effective CPR training is important for provision of high-quality bystander cardiopulmonary resuscitation (CPR). However, the COVID-19 pandemic has hindered conventional face-to-face CPR training. To overcome the limitation, we developed a distance learning CPR training course (HEROS-Remote) that utilized a smartphone app and a delivery-collection system for CPR training manikins. The objective of the study was to evaluate the efficacy of the HEROS-Remote course by comparing chest compression quality between trainees who participated in the conventional CPR training (C-training) and HEROS-Remote course (R-training). Methods: The non-inferiority trial included adult nonhealthcare providers who applied for CPR training. Both groups underwent 2-minute post-training chest compression test followed by course survey on trainees’ course and delivery system satisfaction. The primary outcome of the study was mean chest compression depth during the 2-minute post-training test. Results: A total of 180 trainees were enrolled with 90 trainees for each training group. There was no statistically significant difference in chest compression depth between R-training and C-training groups (67.4 vs. 67.8, p=0.78) as well as proportion of adequate chest compression depth, chest compression rate, proportion of chest compressions with complete chest recoil and chest compression score (90.8 vs. 92.1, p=0.69; 110.8 vs. 110.4, p=0.60; 89.8 vs. 94.7, p=0.05; 92.7 vs. 95.5, p=0.16, respectively). In the R-training group, 90.0% of the trainees were satisfied with the course, 96% responded that the delivery system was satisfactory and convenient. Conclusion: The R-training course was noninferior to the C-training course. The distance learning CPR training method utilizing smartphone app and mannikin delivery-collection system had high user satisfaction and was logistically feasible.

Effects of vertical compression during pediatric cardiopulmonary resuscitation using the one-handed chest compression technique

ObjectiveThe posture of the rescuer while performing the one-handed chest compression (OHCC) has not yet been evaluated. This study aimed to investigate the effect of vertical compression during pediatric cardiopulmonary resuscitation (CPR) using the OHCC technique. MethodsThis was a prospective randomized crossover simulation trial. A total of 42 medical doctors conducted a 2-min single-rescuer CPR using the conventional OHCC (Test 1) or vertical OHCC (Test 2) technique on a pediatric manikin. The chest compression and ventilation parameters were measured in real time during the experiments using sensors embedded in the manikin. In addition, the compression force of each technique was measured using a force plate. ResultsThe average and adequate chest compression depth (CCD) were significantly higher in Test 2 than in Test 1 (average depth: 54.0 mm (interquartile range [IQR]: 48.5–56.0) in Test 2 vs. 49.0 mm (IQR: 40.0–54.0) in Test 1, P < 0.001; adequate depth: 99.0% (IQR: 36.3–100.0) in Test 2 vs. 52.0% (IQR: 0.0–98.0) in Test 1, P < 0.001). The average force of compression was also significantly higher in vertical OHCC than that in conventional OHCC (25.7 kg ± 4.4 in vertical OHCC vs. 24.5 kg ± 4.2 in conventional OHCC, P < 0.001). The ventilation parameters were not significantly different between Tests 1 and 2. ConclusionsThe vertical OHCC could provide a deeper and more adequate CCD compared with the conventional OHCC, and the advantages of the vertical OHCC originate from the superiority of the compression force.

Quantitative assessment of chest compression techniques on an infant manikin.

Current cardiopulmonary resuscitation (CPR) guidelines recommend the two-finger technique (TFT) of chest compression (CC) in infants for a single rescuer. We hypothesized that healthcare providers cannot achieve adequate CC depth with TFT, even if using real-time visual feedback (RVF). This was a cross-over study, randomizing participants to perform three sets of 2-min continuous CC, comparing (i) TFT with RVF, (ii) the one-hand technique (OHT) without RVF, and (iii) OHT with RVF. A standard CPR trainer manikin of a 3-month-old infant and a monitor/defibrillator that displays and records the quantitative CC quality were used. We set a target compression depth of 40-50 mm and a target compression rate of 100-120/min. Data were analyzed using the Friedman test and Bonferroni correction. Statistical significance was defined as P-value of< 0.05. Fifty-nine healthcare providers participated in the study. The mean compression depth was 24 mm (interquartile range [IQR], 22-26 mm) in TFT with RVF and 43 mm (IQR, 38-48 mm) in OHT without RVF, P < 0.001. The proportion of adequate CC depth was 0% (IQR, 0-0%) in TFT with RVF, 22% (IQR, 5-54%) in OHT without RVF, and 62% (IQR, 29-83%) in OHT with RVF. The mean compression rate was within the target range in all three techniques. The TFT cannot produce the CC depth that meets the recommendation of the current CPR guidelines for an infant with RVF, whereas the OHT does.

Impact of personal protective equipment on the effectiveness of chest compression - A systematic review and meta-analysis.

Background and objectivesTo assess the impact of personal protective equipment (PPE) on different aspects of chest compression (CC) during cardiopulmonary resuscitation, we conducted this study.MethodsThis systematic review was performed according to the PRISMA. We searched PubMed, EMBASE and Web of Science from inception to June-6, 2020, limiting to the studies that reported the comparison of the effectiveness of CC in terms of CC rate, CC depth, the proportion of adequate CC rate, the proportion of adequate CC depth or proportion of adequate recoil; in study arms with or without PPE. Risk of bias was assessed by the ROB-2 and ROBINS-I tool. Quantitative data synthesis was done using the generic inverse variance method and the fixed-effects model.ResultsFive simulation-based studies were finally included. A Significant decrease in CC rate (SMD: -0.28, 95%CI: −0.47 to −0.10) and CC depth (SMD: -0.26, 95%CI: −0.44 to −0.07) were observed in the PPE arm as compared to the no-PPE arm. The difference in CC rate was more prominently seen in adult CPR than in paediatric CPR. Without PPE, the proportion of adequate CC rate delivered was 0.74, which reduced significantly to 0.60 after use of PPE (p − 0.035). Similarly, the proportion of adequate CC depth was significantly lesser (p − 0.001) in PPE arm (0.55), as compared to that of the no-PPE arm (0.78).ConclusionThe use of PPE compromises the quality of CC during CPR significantly, and newer ways to deliver chest compression has to be investigated.This study was prospectively registered in PROSPERO (CRD42020192031).

Long-term benefits of chest compression-only cardiopulmonary resuscitation training using real-time visual feedback manikins: a randomized simulation study.

ObjectiveCardiopulmonary resuscitation (CPR) education with a feedback device is known to result in better CPR skills compared to one without the feedback device. However, its long-term benefits have not been established. The purpose of this study was to evaluate the long-term CPR skill retention after training using real-time visual manikins in comparison to that of non-feedback manikins.MethodsWe recruited 120 general university students who were randomly divided into the real-time feedback group (RTFG) and the non-feedback group. Of them, 95 (RTFG, 48; non-feedback group, 47) attended basic life support and automated external defibrillation training for 1 hour. For comparison of retention of CPR skills, the two groups were evaluated based on 2-minute chest compression performed immediately after training and at 3, 6, and 9 months. The CPR parameters between the two groups were also compared using a generalized linear model.ResultsAt immediately after training, the performance of RTFG was better in terms of average chest compression depth (51.9±1.1 vs. 45.5±1.1, p<0.001) and a higher percentage of adequate chest compression depth (51.0±4.1 vs. 26.9±4.2, p<0.001). This significant difference was maintained until 6 months after training, but there was no difference at 9 months after training. However, there was no significant difference in the chest compression rate and the correct hand position at any time point.ConclusionCPR training with a real-time visual feedback manikin improved skill acquisition in chest compression depth, but only until 6 months after the training. It could be a more effective educational method for basic life support training in laypersons.

Advantage and Limitation of Using a Visual Feedback Device during Cardiopulmonary Resuscitation Training.

Recent cardiopulmonary resuscitation (CPR) guidelines recommend the use of CPR prompt/feedback devices during CPR training because it can improve the quality of CPR. Chest compression depth and full chest recoil show a trade-off relationship. Therefore, achievement of both targets (adequate chest compression depth and full chest recoil) simultaneously is a difficult task for CPR instructors. This study hypothesized that introducing a visual feedback device to the CPR training could improve the chest compression depth and ratio of full chest recoil simultaneously. The study investigated the effects of introducing a visual feedback device during CPR training by comparing the results of skill tests before and after introducing a visual feedback device. The results of skill tests from 2016 through 2018 were retrospectively reviewed. The strategy of emphasizing chest compression depth was implemented during the CPR training in 2017, and a visual feedback device was introduced in 2018. The interval between the CPR training and skill tests was seven days. Feedback was not provided during the skill tests. In total, 159 students completed skill tests. Although the chest compression depth increased significantly from 50 mm (42-54) to 60 mm (59-61) after emphasizing chest compression depth (P < .001), the ratio of full chest recoil decreased simultaneously from 100% (100-100) to 81% (39-98; P < .001). The ratio of full chest recoil increased significantly from 81% (39-98) to 95% (77-100) after introducing a visual feedback device (P = .018). However, the students who did not achieve 80% of the ratio of full chest recoil remained significantly higher than in 2016 (1% in 2016, 49% in 2017, and 27% in 2018; P < .001). Although introducing a visual feedback device during CPR training resulted in increasing the ratio of full chest recoil while maintaining the adequacy of chest compression depth, 27% of the students still did not achieve 80% of the ratio of full chest recoil. Another educational strategy should be considered to increase the qualities of CPR more completely.

Certified Basic Life Support Instructors Identify Improper Cardiopulmonary Resuscitation Skills Poorly: Instructor Assessments Versus Resuscitation Manikin Data.

During basic life support (BLS) training, instructors assess learners' cardiopulmonary resuscitation (CPR) skills and correct errors to ensure high-quality performance. This study aimed to investigate certified BLS instructors' assessments of CPR skills. Data were collected at BLS courses for medical students at Aarhus University, Aarhus, Denmark. Two certified BLS instructors evaluated each learner with a cardiac arrest test scenario, where learners demonstrated CPR on a resuscitation manikin for 3.5 minutes. Instructors' assessments were compared with manikin data as reference for correct performance. The first 3 CPR cycles were analyzed. Correct chest compressions were defined as 2 or more of 3 CPR cycles with 30 ± 2 chest compressions, 50 to 60 mm depth, and 100 to 120 min rate. Correct rescue breaths were defined as 50% or more efficient breaths with visible, but not excessive manikin chest inflation (for instructors) or 500 to 600mL air (manikin data). Overall, 90 CPR assessments were performed by 16 instructor pairs. Instructors passed 81 (90%) learners, whereas manikin pass rate was 2%. Instructors identified correct chest compressions with a sensitivity of 0.96 [95% confidence interval (CI) = 0.79-1) and a specificity of 0.05 (95% CI = 0.01-0.14), as well as correct rescue breaths with a sensitivity of 1 (95% CI = 0.40-1) and a specificity of 0.07 (95% CI = 0.03-0.15). Instructors mistakenly failed 1 learner with adequate chest compression depth, while passing 53 (59%) learners with improper depth. Moreover, 80 (89%) improper rescue breath performances were not identified. Certified BLS instructors assess CPR skills poorly. Particularly, improper chest compression depth and rescue breaths are not identified.

Variations in chest compression time, ventilation time and rescuers' heart rate during conventional cardiopulmonary resuscitation in trained male rescuers.

ObjectiveThis study was conducted to determine why rescuers could maintain adequate chest compression depth for longer periods during conventional cardiopulmonary resuscitation (CPR).MethodsVarious CPR parameters, including average compression depth (ACD), average compression rate, average ventilation time (AVT), and rescuers’ heart rates were recorded in real-time when 20 health care providers performed 10 minutes of conventional CPR during a simulation experiment.ResultsThe ACD was maintained above 50 mm and was not significantly different during 19 consecutive CPR cycles. The average compression rate increased from 114.9±10.0/min (2nd cycle) to 120.1±13.8/min (18th cycle) (P=0.007), and the AVT increased from 8.7±1.5 seconds (3rd cycle) to 10.1±2.6 seconds (18th cycle) (P=0.002). The rescuers’ heart rates also increased gradually for 10 min; however, they increased rapidly and were highest during the ventilation phase. Their heart rates then decreased and were lowest during the early chest compression phases of each CPR cycle. Decreases in heart rates were significant in all CPR cycles (average decrease: 14.5±4.5 beats/min, P<0.001).ConclusionThe ACD was maintained adequately during 10 minutes of conventional CPR. However, the AVT increased significantly during the 10-minute period. The rescuers’ heart rates increased and decreased throughout all CPR cycles. These results showed that the ventilation phase might play a role as a resting period and be a reason for the maintenance of adequate chest compression depth for prolonged periods during conventional CPR.

Chest Compression Depth and Rate - Effect on Instructor Visual Assessment of Chest Compression Quality.

The aim of the present study was to determine whether instructors could accurately assess chest compression quality visually, considering the association between chest compression depth and rate. Methods and Results: In this prospective, observational study, the quality of chest compressions performed by a simulated actor in a video was visually assessed by certified instructors. The film consisted of 14 case scenarios, each including a combination of depth (2 patterns: adequate, 5-6 cm; and inadequate, <5 cm) and rate (7 categories: compressions 90-150 times/min in increments of 10 times/min). The participants evaluated whether the compression depth was adequate, deep, or inadequate; and whether the compression rate was appropriate, fast, or slow. Of 198 instructors, 56% of participants misidentified adequate depth as deep at a chest compression rate of 120/min (the tendency toward this response increased as chest compression rate increased), and 64.1% of participants incorrectly determined 130/min to be appropriate. On generalized linear mixed-effects model analysis, perceived chest compression depth and rate were significant factors for a correct response (P<0.01, both). A significant interaction between chest compression depth and rate was observed (P<0.01). In the visual assessment of chest compression quality, recognition of chest compression depth was closely associated with compression rate. Misidentification of adequate chest compression depth as deep increased as the compression rate increased.

A Novel Method of Newborn Chest Compression: A Randomized Crossover Simulation Study.

Objective: To compare a novel two-thumb chest compression technique with standard techniques during newborn resuscitation performed by novice physicians in terms of median depth of chest compressions, degree of full chest recoil, and effective compression efficacy.Patients and Methods: The total of 74 novice physicians with less than 1-year work experience participated in the study. They performed chest compressions using three techniques: (A) The new two-thumb technique (nTTT). The novel method of chest compressions in an infant consists in using two thumbs directed at the angle of 90° to the chest while closing the fingers of both hands in a fist. (B) TFT. With this method, the rescuer compresses the sternum with the tips of two fingers. (C) TTHT. Two thumbs are placed over the lower third of the sternum, with the fingers encircling the torso and supporting the back.Results: The median depth of chest compressions for nTTT was 3.8 (IQR, 3.7–3.9) cm, for TFT−2.1 (IQR, 1.7–2.5) cm, while for TTHT−3.6 (IQR, 3.5–3.8) cm. There was a significant difference between nTTT and TFT, and TTHT and TFT (p < 0.001) for each time interval during resuscitation. The degree of full chest recoil was 93% (IQR, 91–97) for nTTT, 99% (IQR, 96–100) for TFT, and 90% (IQR, 74–91) for TTHT. There was a statistically significant difference in the degree of complete chest relaxation between nTTT and TFT (p < 0.001), between nTTT and TTHT (p = 0.016), and between TFT and TTHT (p < 0.001).Conclusion: The median chest compression depth for nTTT and TTHT is significantly higher than that for TFT. The degree of full chest recoil was highest for TFT, then for nTTT and TTHT. The effective compression efficiency with nTTT was higher than for TTHT and TFT. Our novel newborn chest compression method in this manikin study provided adequate chest compression depth and degree of full chest recoil, as well as very good effective compression efficiency. Further clinical studies are necessary to confirm these initial results.

Why should we switch chest compression providers every 2 minutes during cardiopulmonary resuscitation?

Objective. This study was conducted to determine whether trained male rescuers could maintain adequate chest compres-sion depth (CCD) for longer than the cur-rent recommended guidelines of 2 minutes. Methods. Forty male medical doctors ad-ministered a 5-minute single rescuer car-diopulmonary resuscitation (CPR) to a manikin on the floor with conventional CPR or randomly administered continu-ous chest compressions (CCC). The ratio of compression to ventilation was set to 30:2 with mouth-to-mouth technique dur-ing conventional CPR. Chest compression data were recorded with an accelerometer device and divided into 1-minute segments for analysis.Results. Although average CCD main-tained the recommended depths through-out 5 minutes in conventional CPR, it de-creased significantly with CCC (1 minute: 55.4 ± 4.5 mm; 2 minutes: 54.2 ± 5.4 mm; 3 minutes: 52.6 ± 5.6 mm; 4 minutes: 51.6 ± 5.5 mm; 5 minutes: 49.9 ± 5.8 mm, p < 0.001). The average chest compression numbers (ACCN) per minute were main-tained over 80/min and have not been changed significantly within 5 minutes in the CCC. However, it didn’t reach to the 80/min and decreased significantly after 3minutes compared to the baseline ACCN during first 1-minute segment in the con-ventional CPR.Conclusions. Despite the chest compres-sion providers being limited to trained male medical doctors, the average CCD decreased significantly within 5minutes with CCC. Although maintaining adequate CCD, ACCN in each minute decreased sig-nificantly after 3minutes in the conventional CPR. Therefore, we should rotate chest compression providers every 2minutes re-gardless of the rescuer’s qualifications and CPR methods.

Resuscitation quality of rotating chest compression providers at one-minute vs. two-minute intervals: A mannequin study

ObjectiveThe aim of this randomized cross-over study was to compare one-minute and two-minute continuous chest compressions in terms of chest compression only CPR quality metrics on a mannequin model in the ED. Materials and methodsThirty-six emergency medicine residents participated in this study. In the 1-minute group, there was no statistically significant difference in the mean compression rate (p=0.83), mean compression depth (p=0.61), good compressions (p=0.31), the percentage of complete release (p=0.07), adequate compression depth (p=0.11) or the percentage of good rate (p=51) over the four-minute time period. Only flow time was statistically significant among the 1-minute intervals (p<0.001). In the 2-minute group, the mean compression depth (p=0.19), good compression (p=0.92), the percentage of complete release (p=0.28), adequate compression depth (p=0.96), and the percentage of good rate (p=0.09) were not statistically significant over time. In this group, the number of compressions (248±31 vs 253±33, p=0.01) and mean compression rates (123±15 vs 126±17, p=0.01) and flow time (p=0.001) were statistically significant along the two-minute intervals. There was no statistically significant difference in the mean number of chest compressions per minute, mean chest compression depth, the percentage of good compressions, complete release, adequate chest compression depth and percentage of good compression between the 1-minute and 2-minute groups. ConclusionThere was no statistically significant difference in the quality metrics of chest compressions between 1- and 2-minute chest compression only groups.

Novel Chest Compression Depth Measurement Sensor Using IR-UWB for Improving Quality of Cardiopulmonary Resuscitation

Cardiac arrest is a common cause of death in the world. Immediate high-quality cardiopulmonary resuscitation (CPR) improves the chances of survival of cardiac arrest patients. In particular, maintaining an adequate chest compression depth (CCD) during CPR is a key determinant for survival from cardiac arrest. If it is possible to measure the CCD accurately during CPR, we could increase the survival rate of patients by improving the quality of CPR. This work proposes a new sensor that could measure the CCD accurately during CPR. Compared with existing sensors that utilize pressures or accelerometers, the proposed sensor employs distance measurements based on the time-difference-of-arrival using impulse-radio ultra-wideband (IR-UWB). The method directly measures the CCD using two antennas at the chest and at the back, thereby eliminating the distance error under CPR environments, which is present in existing accelerometer sensors. The designed sensor has an 0.08 mm resolution, and an inaccuracy of less than ±1.25 mm, within a range of 0-40 cm. This sensor was applied to a CPR manikin to measure the CCD in an environment where CPR is performed.

A randomized comparison of three chest compression techniques and associated hemodynamic effect during infant CPR: A randomized manikin study

IntroductionPediatric cardiac arrest is an uncommon but critical life-threatening event requiring effective cardiopulmonary resuscitation. High-quality cardio-pulmonary resuscitation (CPR) is essential, but is poorly performed, even by highly skilled healthcare providers. The recently described two-thumb chest compression technique (nTTT) consists of the two thumbs directed at the angle of 90° to the chest while having the fingers fist-clenched. This technique might facilitate adequate chest-compression depth, chest-compression rate and rate of full chest-pressure relief. Methods42 paramedics from the national Emergency Medical Service of Poland performed three single-rescuer CPR sessions for 10 minutes each. Each session was randomly assigned to the conventional two-thumb (TTHT), the conventional two-finger (TFT) or the nTTT. The manikin used for this study was connected with an arterial blood pressure measurement device and blood measurements were documented on a 10-seconds cycle. ResultsThe nTTT provided significant higher systolic (82 vs. 30 vs. 41 mmHg). A statistically significant difference was noticed between nTTT and TFT (p<.001), nTTT and TTHT (p<0.001), TFT and TTHT (p=0.003). The median diastolic preassure using nTTT was 16 mmHg compared with 9 mmHg for TFT (p<0.001), and 9.5 mmHg for TTHT (p<0.001). Mean arterial pressure using distinct methods varied and amounted to 40 vs. 22. vs. 26 mmHg (nTTT vs. TFT vs. TTHT, respectively). A statistically significant difference was noticed between nTTT and TFT (p<0.001), nTTT and TTEHT (p<0.001), and TFT and TTHT (p<0.001). The highest median pulse pressure was obtained by the nTTT 67.5 mmHg. Pulse pressure was 31.5 mmHg in the TTHT and 24 mmHg in the TFT. The difference between TFT and TTHT (p=0.025), TFT and nTTT (p<0.001), as well as between TTHT and nTTT (p<0.001) were statistically significant. ConclusionsThe new nTTT technique generated higher arterial blood pressures compared to established chest compression techniques using an infant manikin model, suggesting a more effective chest compression. Our results have important clinical implications as nTTT was simple to perform and could be widely taught to both healthcare professionals and bystanders. Whether this technique translates to improved outcomes over existing techniques needs further animal studies and subsequent human trials.

Relationship between chest compression depth and novice rescuer body weight during cardiopulmonary resuscitation

ObjectiveThis study determined if rescuer body weight is a major determinant of chest compression depth (CCD) among novice rescuers by analyzing the results of cardiopulmonary resuscitation (CPR) skill tests among medical students and determined the body weight threshold for those unable to achieve adequate CCD. MethodsRetrospective analysis of CPR test results was performed. A total of 107 medical students completed the tests, which included 5 cycles of CPR. Data were collected using a ResusciAnne SkillReporter. Anthropometric data including participant body weight, body mass index, and height were also collected. The relationships between CCD and anthropometric data were evaluated by Pearson correlation coefficient. In addition, univariate linear regression analysis was used to assess the association between body weight and CCD. ResultsThe highest positive correlation was found between CCD and body weight (r = 0.636, P < .001). Body weight correlated with CCD by as much as 40.5% (R2 = 40.5, P < .001). Using a regression model, we described the association between body weight and CCD as follows: expected CCD (mm) = 0.46 × body weight + 17.59. The regression equation shows that rescuers weighing more than 70.5 kg could achieve a CCD of 50 mm. ConclusionsRescuer body weight is a major determinant of CCD in novice rescuers. Based on these findings, if 2 or more rescuers are available to perform CPR, chest compression should preferentially be performed by rescuers of healthy weight or overweight.

Proper target depth of an accelerometer-based feedback device during CPR performed on a hospital bed: a randomized simulation study

PurposeFeedback devices are used to improve chest compression (CC) quality related to survival rates in cardiac arrest. However, several studies have shown that feedback devices are not sufficiently reliable to ensure adequate CC depth on soft surfaces. Here, we determined the proper target depth of feedback (TDF) using an accelerometer during cardiopulmonary resuscitation in hospital beds. MethodsIn prospective randomized crossover study, 19 emergency physicians performed CCs for 2 minutes continuously on a manikin in 2 different beds with 3 TDFs (5, 6, and 7 cm). We measured CC depth, the proportion of accurate compression depths, CC rate, the proportion of incomplete chest decompressions, the velocity of CC (CC velocity), the proportion of time spent in CC relative to compression plus decompression (duty cycle), and the time spent in CC (CC time). ResultsMean (SD) CC depths at TDF 5, 6, and 7 were 45.42 (5.79), 52.68 (4.18), and 58.47 (2.48) on one bed and 46.26 (4.49), 53.58 (3.15), and 58.74 (2.10) mm on the other bed (all P < .001), respectively. The proportions of accurate compression depths and CC velocity at TDF 5, 6, and 7 differed significantly according to TDF on both beds (all P < .001).The CC rate, CC time, and proportion of incomplete chest decompression did not differ on both beds (all P > .05). The duty cycle differed significantly on only B2. ConclusionsThe target depth of the real-time feedback device should be at least 6 cm but should not exceed 7 cm for optimal CC on patients on hospital beds.

Effectiveness and feasibility of assistant push on improvement of chest compression quality: a crossover study

PurposeTo improve the quality of chest compression (CC), we developed the assistant-push method, whereby the second rescuer pushes the back of the chest compressor during CC. We investigated the effectiveness and feasibility of assistant push in achieving and maintaining the CC quality. MethodsThis was a randomized crossover trial in which 41 subjects randomly performed both of standard CC (single-rescuer group) and CC with instructor-driven assistant push (assistant-push group) in different order. Each session of CC was performed for 2 minutes using a manikin. Subjects were also assigned to both roles of chest compressor and assistant and together performed CC with subject-driven assistant push. Depth of CC, compression to recoil ratio, duty cycle, and rate of incomplete recoil were quantified. ResultsThe mean depth of CC (57.0 [56.0-59.0] vs 55.0 [49.5-57.5], P < .001) was significantly deeper, and the compression force (33.8 [29.3-36.4] vs 23.3 [20.4-25.3], P < .001) was stronger in the assistant-push group. The ratio of compression to recoil, duty cycle, and rate of incomplete chest recoil were comparable between the 2 groups. The CC depth in the single-rescuer group decreased significantly every 30 seconds, whereas in the assistant-push group, it was comparable at 60- and 90-second time points (P = .004). The subject assistant-push group performed CCs at a depth comparable with that of the instructor assistant-push group. ConclusionThe assistant-push method improved the depth of CC and attenuated its decline, eventually helping maintain adequate CC depth over time. Subjects were able to feasibly learn assistant push and performed effectively.