A novel CPR-assist device vs. established chest compression techniques in infant CPR: A manikin study.

INTRODUCTION: Guidelines for infant CPR recommend the two-thumb encircling hands technique (TTT) and the two-finger technique (TFT) for chest compression. Some devices have been designed to assist with infant CPR, but are often not readily available. Syringe plungers may serve as an alternative infant CPR assist device given their availability in most hospitals. In this study, we aimed to determine whether CPR using a syringe plunger could improve CPR quality measurements on the Resusci-Baby manikin compared with traditional methods of infant CPR. METHODS: Compression area with a diameter of 1 to 2 cm is recommended in previous infant CPR device researches. In this is a randomized crossover manikin study, we examined the efficacy of the Syringe Plunger Technique (SPT) which uses the plunger of the 20 ml syringe with a 2 cm diameter flat piston, commonly available in hospital, for infant External Chest Compressions (ECC). Participants performed TTT, TFT and SPT ECC on Resusci® Baby QCPR® according to 2020 BLS guidelines. RESULTS: Sixty healthcare providers participated in this project. The median (IQR) ECC depths in the TTT, TFT and SPT in the first minute were 41 mm (40-42), 40 mm (38-41) and 40 mm (39-41), respectively, with p < 0.001. The median (IQR) ECC recoil in the TTT, TFT and SPT groups in the first minute was 15% (1-93), 64% (18-96) and 53% (8-95), respectively, with p = 0.003. The result in the second minute had similar findings. The SPT had the best QCPR score and less fatigue. CONCLUSION: The performance of chest compression depth and re-rebound ratio was statistically different among the three groups. TTT has good ECC depth and depth accuracy but poor recoil. TFT is the complete opposite. SPT can achieve a depth close to TTT and has a good recoil performance as TFT. Regarding comprehensive performance, SPT obtains the highest QCPR score, and SPT is also less fatigued. SPT may be an effective alternative technique for infant CPR.

Effect of thoracic stiffness on chest compression performance - A prospective randomized crossover observational manikin study.

Introduction: Human thoracic stiffness varies and may affect the performance during external chest compression (ECC). The Extra Compression Spring Resusci® QCPR Anne manikin is a high-fidelity training model developed for ECC training that can account for varying levels of thoracic stiffness. The aim of this study was to use this training model to investigate the effects of thoracic stiffness on ECC biomechanics and qualities. Methods: Fifty-two participants performed standard ECC on the manikin with different thoracic springs to simulate varying levels of thoracic stiffness. The MatScan Pressure Measurement system was used to investigate the ECC pressure and force distribution. Results: The hard spring group's performance had a better complete recoil ratio (90.06 ± 24.84% vs. 79.75 ± 32.17% vs. 56.42 ± 40.15%, p < 0.001 at second minute), but was more inferior than the standard and soft spring groups in overall quality, ECC depth (34.17 ± 11.45 mm vs. 41.25 ± 11.42 mm vs. 51.88 ± 7.56, p < 0.001 at second minutes), corrected depth ratio, and corrected rate ratio. The hard spring group had less radial-ulnar peak pressure difference (kgf/cm2) than the other two groups (-0.28 ± 0.38 vs. -0.30 ± 0.43 vs. -0.47 ± 0.34, p = 0.01), demonstrating that more symmetrical pressure was applied in the hard spring group. The soft spring group had better ECC depth, corrected depth ratio, corrected rate ratio, and overall quality, but its performance in complete recoil was inferior, and unbalanced pressure was more liable to cause injury. Hard springs caused operator fatigue easily. Conclusion: The thoracic stiffness greatly affected the performance of ECC. Our findings provided information for more effective ECC practices and training.

Biomechanical analysis of force distribution in one-handed and two-handed child chest compression- a randomized crossover observational study.

BACKGROUND: Even force distribution would generate efficient external chest compression (ECC). Little research has been done to compare force distribution between one-hand (OH) and two-handed (TH) during child ECC. Therefore, this study was to investigate force distribution, rescuer perceived fatigue and discomfort/pain when applying OH and TH ECC in children. METHODS: Crossover manikin study. Thirty-five emergency department registered nurses performed lone rescuer ECC using TH and OH techniques, each for 2 min at a rate of at least 100 compressions/min. A Resusci Junior Basic manikin equipped with a MatScan pressure measurement system was used to collect data. The perceived exertion scale (modified Borg scale) and numerical rating scale (NRS) was applied to evaluate the fatigue and physical pain of delivering chest compressions. RESULTS: The maximum compression force (kg) delivered was 56.58 ± 13.67 for TH and 45.12 ± 7.90 for OH ECC (p <  0.001). The maximum-minimum force difference force delivered by TH and OH ECC was 52.24 ± 13.43 and 41.36 ± 7.57, respectively (p <  0.001). The mean caudal force delivered by TH and OH ECC was 29.45 ± 16.70 and 34.03 ± 12.01, respectively (p = 0.198). The mean cranial force delivered by TH and OH ECC was 27.13 ± 11.30 and 11.09 ± 9.72, respectively (p <  0.001). The caudal-cranial pressure difference delivered by TH and OH ECC was 19.14 ± 15.96 and 26.94 ± 14.48, respectively (p = 0.016). The perceived exertion and NRS for OH ECC was higher than that of the TH method (p < 0.001, p = 0.004, respectively). CONCLUSIONS: The TH method produced greater compression force, had more efficient compression, and delivered a more even force distribution, and produced less fatigue and physical pain in the rescuer than the OH method. TRIAL REGISTRATION: The Cheng Kung University Institutional Review Board A-ER-103-387. http://nckuhirb.med.ncku.edu.tw/sitemap.php.

Biomechanical analysis of force distribution in one-handed and two-handed adult chest compression: a randomised crossover observational study.

INTRODUCTION: The standard method of chest compression for adults is a two-handed procedure. One-handed external chest compression (ECC) is used in some situations such as during transport of patients who had an out-of-hospital cardiac arrest, but the quality of one-handed ECC is still not well known. The distribution of force is related to the quality of chest compression and may affect the risk of injury. This study aimed to determine the differences in the quality and potential safety concern between one-handed ECC and two- handed ECC. METHODS: In this randomised crossover study, participants recruited from National Cheng Kung University Hospital and the ambulance team from the fire bureau were asked to perform one-handed and two-handed ECC on the Resusci Anne manikin according to standard 2015 ECC guidelines. The MatScan Pressure Measurement system was used to investigate the compression pressure and force distribution. RESULTS: Two-handed ECC had better results than one-handed ECC in terms of the median (IQR) depth (51.00 (41.50-54.75) mm vs 42.00 (27.00-49.00) mm, p=0.018), the proportion of depth accuracy (82.05% (13.95%-99.86%) vs 11.17% (0.00%-42.13%), p=0.028) and the proportion of incomplete recoil (0.23% (0.01%-0.44%) vs 2.42% (0.60%-4.21%), p=0.002). The maximum force (45.72 (36.10-80.84) kgf vs 35.64 (24.13-74.34) kgf, p<0.001) and ulnar-radial force difference (7.13 (-16.58 to 21.07) kgf vs 23.93 (11.19-38.74) kgf, p<0.001) showed statistically significant differences. The perceived fatigue of two-handed ECC versus one-handed ECC was 5.00 (3.00-6.00) vs 6.00 (5.00-8.00), p<0.001. CONCLUSION: The quality of one-handed ECC, based on depth and recoil, is worse than that of standard two-handed ECC. The pressure and force distribution of one-handed ECC result in greater ulnar pronation of the hand than that of two-handed ECC. One-handed ECC more easily causes operator fatigue. Acknowledging these findings and adjusting training for one-handed ECC would potentially improve the quality of cardiopulmonary resuscitation during transport.

How does the side of approach impact the force delivered during external chest compression?

BACKGROUND: We investigated the biomechanics of four external chest compression (ECC) approaches involving different sides of approach and hand placement during cardiopulmonary resuscitation (CPR). METHODS: A total of 60 participants (30 women and 30 men) with CPR certification performed standard continuous 2-min ECC on a Resusci Anne manikin with real-time feedback in four scenarios: rescuer at the manikin's right side with right hand chest contact (RsRc), rescuer at the manikin's right side with left hand chest contact (RsLc), rescuer at the manikin's left side with left hand chest contact (LsLc), and rescuer at the manikin's left side with right hand chest contact (LsRc). Pressure distribution maps of the palm, peak compression pressure, and compression forces were analysed. RESULTS: The participants' mean age, height, and weight was 24.8 ± 4.8 years, 165.8 ± 8.7 cm, and 62.7 ± 13.5 kg, respectively. Of the participants, 58 and 2 were right- and left-handed, respectively. Significant between-scenario differences were observed in ulnar-side palm pressure. Ulnar-radial pressure differences were higher in the LsLc and RsRc groups than in the LsRc and RsLc groups (0.69 ± 0.62 and 0.73 ± 050 kg/cm2 vs. 0.49 ± 0.49 and 0.50 ± 0.59 kg/cm2; respectively; p < 0.05). Ulnar-radial force differences were higher in the LsLc and RsRs groups than in the sLsLc and RsRs groups. CONCLUSIONS: The higher differences in pressure and force under the LsLc and RsRc approaches may lead to higher risks of potential injury. When performing standard-quality ECC, the LsRc and RsLc approaches, in which compression pressure and force are better distributed, may be more suitable than RsRc or LsLc.

Biomechanics of two-thumb versus two-finger chest compression for cardiopulmonary resuscitation in an infant manikin model.

OBJECTIVE: The loading force applied in infant external chest compression (ECC) has not been determined. The objective of this crossover study was to quantify the actual force involved in two-thumb (TT)-encircling hands and two-finger (TF) methods during infant cardiopulmonary resuscitation. METHODS: A total of 42 emergency medical professionals performed lone rescuer infant external chest compression (ECC) with TF and TT methods. The order of two methods was arranged randomly, with an interval of 30 min in between. The force was collected by MatScan as primary outcomes. The secondary outcomes, quality of chest compressions, and fatigue level were also recorded by SkillReporter and perceived exertion scale. RESULTS: Using the TT method, the rescuers performed cardiopulmonary resuscitation (CPR) with higher ECC quality, but more incomplete recoil than they did using the TF method. The mean compression forces delivered in the first and second minutes were 3.53 ± 1.27 kg and 3.22 ± 1.11 kg (P = 0.012) for TF and 4.11 ± 1.80 kg and 4.04 ± 1.83 kg (P = 0.568) for TT, respectively. Pairwise comparison indicates that the compression force delivered through the TF method during the first and second minute of ECC were inferior to that delivered through the TT method. The TF method involved greater perceived exertion than the TT method (5.27 ± 4.69 vs. 4.02 ± 2.31; P = 0.007). The median perceived exertions for the TF and TT methods were 5 and 4, respectively. CONCLUSION: For infant CPR, the TT method involved greater loading force, lower fatigue, and higher overall ECC quality than the TF method. The optimal compression force is about 3.8-4.3 kg.

Effects of Kinesio taping and exercise on forward head posture.

BACKGROUND: Little is known about the effects of Kinesio taping and therapeutic exercise on correcting forward head posture. OBJECTIVE: To compare Kinesio taping versus therapeutic exercise for forward head posture on static posture, dynamic mobility and functional outcomes. METHODS: Sixty subjects (31 women, 29 men) with forward head postures participated in this study. They were randomly assigned to either one of the three groups: (1) exercise group (n = 20), (2) taping group (n = 20), and (3) control groups (n = 20). The horizontal forward displacement (HFD) between ear lobe and acromion process, upper cervical and lower cervical angle (UCA, LCA), active range of motion (AROM) of cervical spine, and neck disability index (NDI) were measured before and after a 5-week intervention, and a 2-week follow-up. Data were analyzed by means of a mixed design repeated-measures ANOVA. RESULTS: Both taping and exercise groups showed significant improvements in HFD compared with the control group at post-treatment and follow-up. Compared with the control group, the exercise group exhibited significant improvements in the LCA and the side bending AROM at post-treatment. CONCLUSIONS: Both Kinesio taping and therapeutic exercise improve forward head posture after intervention and a 2-week follow-up. The effectiveness of therapeutic exercise is better than taping.

Push-fast recommendation on performing CPR causes excessive chest compression rates, a manikin model.

BACKGROUND: Increasing chest compression rate during cardiopulmonary resuscitation can affect the workload and, ultimately, the quality of chest compression. This study examines the effects of compression at the rate of as-fast-as-you-can on cardiopulmonary resuscitation (CPR) performance. METHODS: A crossover, randomized-to-order design was used. Each participant performed chest compressions without ventilation on a manikin with 2 compression rates: 100 per minute (100-cpm) and "push as-fast-as you-can" (PF). The participants performed chest compressions at a rate of either 100-cpm or PF and subsequently switched to the other after a 50-minute rest. RESULTS: Forty-two CPR-qualified nonprofessionals voluntarily participated in the study. During the PF session, the rescuers performed CPR with higher compression rates (156.8 vs 101.6 cpm), more compressions (787.2 vs 510.8 per 5 minutes), and more duty cycles (51.0% vs 41.7%), but a lower percentage of effective compressions (47.7% vs 57.9%) and a lower compression depth (35.6 vs 38.0 mm) than they did during the 100-cpm session. The CPR quality deteriorated in numbers and percentile of effective compression since the third minute in the PF session and the fourth minute in the 100-cpm session. The percentile of compressions with adequate depth in the 100-cpm sessions was higher than that in the PF sessions during the second, third, and fourth minutes of CPR. CONCLUSION: Push-fast technique showed a significant decrease in the percentile of effective chest compression compared with the 100-cpm technique during the 5-minute hand-only CPR. The PF technique exhibited a trend toward increased fatigue in the rescuers, which can result in early decay of CPR quality.

Electromyography activity of selected trunk muscles during cardiopulmonary resuscitation.

BACKGROUND: Understanding trunk muscle activity during chest compression may improve cardiopulmonary resuscitation (CPR) training strategies of CPR or prevent low back pain. This study investigates the trunk muscle activity pattern of chest compression in health care providers to determine the pattern alternation during chest compression. METHODS: Thirty-one experienced health care providers performed CPR for 5 minutes at a frequency of 100 compressions per minute. An electromyography (EMG) system was used to record muscle activity in the first minute, the third minute, and the fifth minute. Electrodes were placed bilaterally over the pectoralis major, latissimus dorsi, rectus abdominis, erector spinae, and gluteus maximus. We calculated the root mean square (RMS) value and maximal amplitude of the EMG activity, median frequency, and delivered force. RESULTS: The maximal amplitude of EMG of the pectoralis major, erector spinae, and rectus abdominis showed large muscle activity above 45% of maximal voluntary contraction under chest compression. There were no significant differences in the RMS value of one chest compression cycle (RMS100%) and median frequency for all muscles at the first, third, and fifth minutes. Only gluteus maximus showed significant imbalance. The EMG ratios (erector spinae/rectus abdominis; erector spinae/gluteus maximus) increased significantly over time. The delivered force, compression depth, and number of correct depth decreased significantly over time. CONCLUSION: We suggest that the muscle power training for the pectoralis major, erector spinae, and rectus abdominis could be helpful for health care providers. Keeping muscle activity balance of bilateral gluteus maximus and maintaining the same level of EMG ratios might be the keys to prevent low back pain while performing CPR.

Effects of compression-to-ventilation ratio on compression force and rescuer fatigue during cardiopulmonary resuscitation.

INTRODUCTION: Although increasing consecutive compressions during cardiopulmonary resuscitation (CPR) is beneficial to patients, it possibly affects the workload and, ultimately, the quality of CPR. This study examines the effects of compression-to-ventilation ratio on external chest compression performance of rescuers. METHODS: Subjects were 17 health care providers. Each participant performed CPR with 3 compression-to-ventilation ratios: 15:2, 30:2, and 50:5. The duration of CPR was 5 minutes in each group, with a rest period of 50 minutes in between. The manikin was equipped with a 6-axis force load cell to measure the force applied. An 8-camera digital motion analysis system was used to collect the 3-dimensional trajectory information. Data were compared using the crossover design. Ratings of perceived exertion and body area discomfort were measured. RESULTS: The mean compression forces (in Newtons) delivered at 1 minute 20 seconds to 1 minute 40 seconds and at 4 minutes 20 seconds to 4 minutes 40 seconds were 494.65 ± 53.58 and 478.64 ± 50.29, respectively (P = .047), for compression-to-ventilation ratios of 15:2; 473.57 ± 49.69 and 435.59 ± 56.79, respectively (P < .001), for ratios of 30:2; and 468.44 ± 38.05 and 442.18 ± 43.40, respectively (P = .012), for ratio of 50:5. Diminished compression force in the ratio 50:5 was observed at 1 minute 20 seconds, and in the 30:2 ratio, it was observed at 4 minutes 20 seconds. The mean joint angles in each group did not differ significantly between 1 minute 20 seconds and 4 minutes 20 seconds. The Ratings of Perceived Exertion Scale was 3.38 ± 1.64 in 15:2, 4.06 ± 1.43 in 30:2, and 4.35 ± 1.54 in 50:5 (P = .045). Waist discomfort was noted in 50:5 after 4 minutes 20 seconds of external chest compression. CONCLUSIONS: Rescuer fatigue must be considered when raising the consecutive compression during CPR. Switching the compressor every 2 minutes should be followed where possible.

Comparison of chest compression kinematics associated with over-the-head and standard cardiopulmonary resuscitation.

BACKGROUND: Over-the-head cardiopulmonary resuscitation (CPR) is a method of chest compression, which may be easier to perform than standard CPR in a confined space. PURPOSE: The purpose of this study was to evaluate the effects of over-the-head CPR on the kinematics and the force of delivered compressions. METHODS: The subjects were 21 health care providers who were experienced in CPR. Each participant performed over-the-head CPR (O) and standard CPR (S). The compression-to-ventilation ratio was 30:2. The CPR duration was 2 minutes in each position, with a rest period of 15 minutes between each instance. The order in which positions were adopted was randomized. A manikin was equipped with a 6-axial force load cell to collect 3-dimensional compression forces at a sampling rate of 1000 Hz. An 8-camera digital motion analysis system was used to collect 3-dimensional trajectory information. Data were compared by crossover design analysis of variance (P < .05 represents statistical significance). RESULTS: No significant differences in range of motion of the head, shoulder, lower trunk, hip, and knee were obtained using the 2 methods. The compression forces in O and S were 386.64 +/- 47.32 and 397.35 +/- 41.89 N, respectively (P > .05). No significant differences between the compression frequencies, depths, and percentages correct were obtained using the 2 methods. CONCLUSIONS: There were no differences between the kinematics, compression forces, depths, and frequencies obtained using the O and S CPR methods as practiced by experienced providers.

Mechanical loading of the low back during cardiopulmonary resuscitation.

AIM: Back pain is often seen in professional rescuers after carrying out resuscitation. Back loading is known to be affected by the working surface height, but the relationship between the surface height and back loading during cardiopulmonary resuscitation (CPR) is poorly understood. The purpose of this study was to examine how back loading changes in response to CPR posture and surface height. METHODS: Twenty-two experienced professional rescuers performed CPR using three surface heights; the floor (F), a table at a height of 63cm (HT) and one at a height of 37cm (LT). RESULTS: The mean and maximal low back moment and compression force at HT were significantly smaller than those at LT and F. CONCLUSION: The results suggest that the HT task of chest compression produces the lowest low back moment and compression force. Thus, HT positioning may decrease the probability of low back pain and is suggested to be optimal height for inexperienced resuscitators, those with back injury, or those requiring a long operating duration.

Effects of rescuer position on the kinematics of cardiopulmonary resuscitation (CPR) and the force of delivered compressions.

BACKGROUND: Depending on the clinical setting, rescuers may provide CPR from a kneeling (if the patient is on the ground) or standing (if the patient is in a bed) position. The rescuer position may affect workload, and hence rate of fatigue and quality of CPR. PURPOSE: This study evaluates how three common rescuer positions affect the kinematics of CPR and the force of delivered compressions. METHODS: Subjects were 18 health care providers experienced in CPR. Each participant performed CPR from three different positions: kneeling beside the Resusci Anne manikin placed on the floor (F); standing beside the manikin placed on a Table 63 cm in height (H), and standing beside the manikin placed on a Table 37 cm in height (L). The compression to ventilation ratio was 15:2. CPR duration was 5 min for each position, with a rest period of 50 min in-between. The order of position was randomised. The manikin was equipped with a six-axial force load cell to collect 3D compression forces at a sampling rate of 1000 Hz. An eight-camera Motion Analysis Digital System was adopted to collect 3D trajectory information. Data were compared using crossover-design analysis of variance (p<0.05 was regarded as statistically significant). Ratings of Perceived Exertion (RPE) were measured by modified Borg scale. RESULTS: Significant differences were observed in the head, shoulder, lower trunk, hip and knee angles between the three methods. Lower trunk flexion angle (degrees) for H, L, and F were -14.52+/-1.13, -28.83+/-1.75, and 14.39+/-1.14, respectively. Hip flexion angle for H, L, and F were -16.21+/-3.30, -42.59+/-4.75, and -47.39+/-4.36, respectively. However, compression force (N) in H, L, and F were 455.8+/-17.6, 455.7+/-14.0, 461.5+/-13.5, respectively (p>0.05). Compression depths (mm) were: 43.5+/-3.4, 42.0+/-5.4, 44+/-5.2, respectively (p>0.05). Compression frequencies (times/min) were: 117.9+/-12.4, 116.6+/-13.4, 108.8+/-11.7, respectively (p>0.05). No differences were found between the three positions for RPE. CONCLUSIONS: In this study, while the kinematics of CPR differed significantly with varying rescuer position, these differences did not affect the compression force, depth and frequency as performed by experienced providers.