A new method of pulse control in cardiopulmonary resuscitation; Continuous femoral pulse check.

OBJECTIVES: The reliability of manual pulse checks has been questioned but is still recommended in cardiopulmonary resuscitation (CPR) guidelines. The aim is to compare the 10-s carotid pulse check (CPC) between heart massage cycles with the continuous femoral pulse check (CoFe PuC) in CPR, and to propose a better location to shorten the interruption times for pulse check. METHODS: A prospective study was conducted on 117 Non-traumatic CPR patients between January 2020 and January 2022. A total of 702 dependent pulse measurements were executed, where carotid and femoral pulses were simultaneously assessed. Cardiac ultrasound, end-tidal CO2, saturation, respiration, and blood pressure were employed for pulse validation. RESULTS: The decision time for determining the presence of a pulse in the last cycle of CPR was 3.03 ± 1.26 s for CoFe PuC, significantly shorter than the 10.31 ± 5.24 s for CPC. CoFe PuC predicted the absence of pulse with 74% sensitivity and 88% specificity, while CPC predicted the absence of pulse with 91% sensitivity and 61% specificity. CONCLUSION: CoFe PuC provides much earlier and more effective information about the pulse than CPC. This shortens the interruption times in CPR. CoFe PuC should be recommended as a new and useful method in CPR guidelines.

A Cluster-Randomized Control Study Comparing a New Cue "Two Compressions per Second" with "100-120 Compressions per Minute" in Training of Bystander Cardiopulmonary Resuscitation.

BACKGROUND: Chest compression at a rate of 100-120 compressions per minute (cpm) during cardiopulmonary resuscitation (CPR) is associated with the highest survival rates. Performing compressions at a faster rate may exhaust the rescuers. OBJECTIVES: To compare a new cue of 'two compressions per second' to the traditional cue of '100-120 compressions per minute' on compression rate in CPR training. METHODS: In this cluster-randomized study, students from two senior high schools were assigned into two groups. For the experimental group, the cue for the compression rate was 'two compressions per second'. For the control group, the cue was '100-120 cpm'. Except the different cues, all participants underwent the same standardized CPR training program. Verbal compression rate-related feedback was not obtained during practice. Quality indicators of chest compressions were recorded by a sensorized manikin. The primary outcome measure was mean compression rate at course conclusion. The secondary outcome measures were individual compression quality indicators at course conclusion and 3 months after training. RESULTS: We included 164 participants (85 participants, experimental group; 79 participants, control group). Both groups had similar characteristics. The experimental group had a significantly lower mean compression rate at course conclusion (144.3 ± 16.17 vs. 152.7 ± 18.38 cpm, p = 0.003) and at 3 months after training (p = 0.09). The two groups had similar mean percentage of adequate compression rate (≥ 100 cpm), mean compression depth, and mean percentage of complete recoil at course conclusion and 3 months after training. CONCLUSION: The new cue of 'two compressions per second' resulted in participants having a lower compression rate, although it still exceeded 120 cpm.

Comparison of two infant cardiopulmonary resuscitation techniques explained by phone in a non-health professionals' population: Two-thumbs encircling hand technique vs. two-fingers technique, a randomised crossover study in a simulation environment.

BACKGROUND: Paediatric out-of-hospital cardiac arrest (OHCA) is the reason for an emergency call in approximately 8/100,000 person-years. Improvement of OHCA resuscitation needs a quality chain of survival and a rapid start of resuscitation. The aim of this study was to compare the efficacy of two resuscitation techniques provided on a mannequin, the two-fingers technique (TFT) and the two-thumbs encircling hand technique (TTHT), explained by a trained emergency call responder on the phone in a population of non-health professionals. METHODS: We conducted a randomised crossover study in the simulation lab of a University Hospital. The participants included in the study were non-health professional volunteers of legal age. The participants were assigned (1:1 ratio) to two groups: group A: TFT then TTHT, group B: TTHT then TFT. Scenario and techniques were discovered during the evaluation. RESULTS: Thirty-five volunteers were randomised before the sessions and 33 ultimately came to the simulation lab. We found a better median QCPR global score during TTHT sessions than during TFT sessions (74 vs. 59, P = 0.046). Linear mixed models showed that the TTHT method was the only variable associated with a better QCPR global score [model 1: ß = 14.3; 95% confidence interval (CI), 2.4-26.2; model 2: ß = 14.5; 95% CI, 2.5-26.6]. CONCLUSION: Our study showed the superiority of TTHT for infant CPR performed by non-health professionals when an emergency call responder advised them over the phone. It seemed to be the best technique for a solo rescuer regardless of previous training.

Efficacy of cardiopulmonary resuscitation performance while wearing a powered air-purifying respirator.

BACKGROUND: The use of personal protective equipment for respiratory infection control during cardiopulmonary resuscitation (CPR) is a physical burden to healthcare providers. The duration for which CPR quality according to recommended guidelines can be maintained under these circumstances is important. We investigated whether a 2-min shift was appropriate for chest compression and determined the duration for which chest compression was maintained in accordance with the recommended guidelines while wearing personal protective equipment. METHODS: This prospective crossover simulation study was performed at a single center from September 2020 to October 2020. Five indicators of CPR quality were measured during the first and second sessions of the study period. All participants wore a Level D powered air-purifying respirator (PAPR), and the experiment was conducted using a Resusci Anne manikin, which can measure the quality of chest compressions. Each participant conducted two sessions. In Session 1, the sequence of 2 min of chest compressions, followed by a 2-min rest, was repeated twice; in Session 2, the sequence of 1-min chest compressions followed by a 1-min rest was repeated four times. RESULTS: All 34 participants completed the study. The sufficiently deep compression rate was 65.9 ± 31.1% in the 1-min shift group and 61.5 ± 30.5% in the 2-min shift group. The mean compression depth was 52.8 ± 4.3 mm in the 1-min shift group and 51.0 ± 6.1 mm in the 2-min shift group. These two parameters were significantly different between the two groups. There was no significant difference in the other values related to CPR quality. CONCLUSIONS: Our findings indicated that 1 min of chest compressions with a 1-min rest maintained a better quality of CPR while wearing a PAPR.

Hands-on defibrillation with safety drapes: Analysis of compressions and an alternate current pathway.

BACKGROUND: Hands-on defibrillation (HOD) could theoretically improve the efficacy of cardiopulmonary resuscitation (CPR) though a few mechanisms. Polyethylene drapes could potentially facilitate safe HOD, but questions remain about the effects of CPR on polyethylene's conductance and the magnitude of current looping through rescuers' arms in contact with patients. METHODS: This study measured the leakage current through 2 mil (0.002 in.) polyethylene through two different current pathways before and after 30 min of continuous compressions on a CPR mannequin. The two pathways analyzed were the standardized IEC (International Electrotechnical Commission) leakage current analysis and a setup analyzing a current pathway looping through a rescuer's arms and returning to the patient. First, ten measurements involving the two pathways were obtained on a single polyethylene drape. 30 min of continuous compressions were applied to the drape on a CPR mannequin after which the ten measurements were repeated. RESULTS: Twenty patients undergoing elective cardioversion for atrial fibrillation (18/20) or atrial flutter (2/20) at Emory University Hospital underwent analysis all receiving 200 J shocks (age 38-101, 35% female). Through the IEC measurement method the peak leakage current mean was 0.70 +/- 0.02 mA before compressions and 0.59 +/- 0.19 mA after compressions. Only three of the ten measurements assessing current passing through a rescuer's arms had detectable current and each was of low magnitude. All measurements were well below the maximum IEC recommendations of 3.5 mA RMS and 5.0 mA peak. CONCLUSIONS: Polyethylene may facilitate safe HOD even after long durations of compressions. Current looping through a rescuer's arms is likely of insignificant magnitude.

Severe Vertebral Body Fracture-Dislocation as a Result of Chest Compressions: A Case Report.

BACKGROUND: Although high-quality chest compressions are an essential, lifesaving component of cardiopulmonary resuscitation, injuries are common with both manual and mechanical chest compressions. CASE REPORT: We discuss the case of a 77-year-old woman who sustained thoracic vertebral fractures after cardiopulmonary resuscitation involving both manual and mechanical chest compressions. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Routine post-cardiac arrest care should include evaluation for chest compression-related injury. If a patient has back pain, focal vertebral tenderness, or paraplegia after chest compressions, imaging to evaluate for vertebral fracture should be performed. If unable to assess for back pain or tenderness, consider imaging to evaluate for vertebral fracture in patients with kyphosis or osteopenia, as these patients are at higher risk for chest compression vertebral injury.

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.

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.

Chest compressions during ventilation in out-of-hospital cardiopulmonary resuscitation cause fragmentation of the airflow.

INTRODUCTION: When a patient suffers an out-of-hospital cardiac arrest, ventilation and chest compressions are often given simultaneously during cardiopulmonary resuscitation. These simultaneous chest compressions may cause a fragmentation of the airflow, which may lead to an ineffective ventilation. This study focusses on the occurrence and quantification of this fragmentation and its effect on ventilation. MATERIALS AND METHODS: This study is a single-center observational study, held at Ghent University Hospital. A custom-built bidirectional flow sensor was used to quantify the volumes of ventilation. Adult cardiac arrest patients who were prehospitally intubated and resuscitated by the medical emergency team were eligible for inclusion. Data of the patients who were ventilated and received simultaneous chest compressions, was used to calculate the volumes of ventilation and the amount and volumes of fragmentation. All data in this study is reported as mean (standard deviation; range). RESULTS: Data of 10 patients (7 male) with a mean age of 71 years (14;51-87) was used in this study. The mean ventilation frequency was 12/min (2;9-16), the mean minute volume and tidal volume were respectively 6.21 L (1.51;3.79-8.15) and 514 mL (99;422-682). Fragmentation of the airflow was observed in all patients, with an average of 3 (1;2-5) fragments per inspiration and a mean volume of 214 mL (65;112-341) per fragment. DISCUSSION AND CONCLUSION: Chest compressions during ventilation caused fragmentation of the airflow in all patients. There was wide variation in the number and volume of the fragments between patients. The importance of quantification of airflow volumes and the effect fragmentation of the airflow on the efficacy of ventilation can be essential in improving cardiopulmonary resuscitation techniques and therefore needs further investigation.

Leg-heel chest compression as an alternative for medical professionals in times of COVID-19.

OBJECTIVE: To evaluate leg-heel chest compression without previous training as an alternative for medical professionals and its effects on distance to potential aerosol spread during chest compression. METHODS: 20 medical professionals performed standard manual chest compression followed by leg-heel chest compression after a brief instruction on a manikin. We compared percentage of correct chest compression position, percentage of full chest recoil, percentage of correct compression depth, average compression depth, percentage of correct compression rate and average compression rate between both methods. In a second approach, potential aerosol spread during chest compression was visualized. RESULTS: Our data indicate no credible difference between manual and leg-heel compression. The distance to potential aerosol spread could have been increased by leg-heel method. CONCLUSION: Under special circumstances like COVID-19-pandemic, leg-heel chest compression may be an effective alternative without previous training compared to manual chest compression while markedly increasing the distance to the patient.

Possibilities of using open chest cardiac massage in sudden, non-traumatic cardiac arrest.

Cardiopulmonary resuscitation is one of the most studied procedures in medicine. Over the years, despite numerous scientific studies, changes in guidelines, refining algorithms, expanding the availability of resuscitation equipment and educating the public, it has not been possible to improve the results of treatment of patients after cardiac arrest. Only 10% of them survive until hospital discharge. There is a well-tested medical procedure, wide application of which could improve results of resuscitation. This procedure is open chest cardiac massage (OCCM). OCCM is not a new technique, its use dates back to the nineteenth century, now it is reserved for patients sustaining trauma and those after surgical procedures. A number of experimental and clinical studies have proven its advantage over the currently preferred indirect massage (CCCM) also in the group of non- traumatic patients. Of course, OCCM is an invasive method with a number of possible complications accompanying surgical procedures, and its wide implementation would require a long-term training program, but it seems that it could be an impulse that would significantly improve survival in this group of patients.

A Randomized Crossover Trial of Conventional versus Modified "Koch" Chest Compressions in a Height-Restricted Aeromedical Helicopter.

Aim: Low overhead height can negatively affect chest compression performance. An adapted compression technique has been proposed by paramedic H. Koch (pron. "Cook"). This study compares conventional to Koch technique in a height-restricted aeromedical helicopter. Methods: Eighteen clinicians were randomized to 2 minutes of conventional or Koch compressions, then crossed-over. Koch technique uses a forearm/elbow instead of overlapping hands. Compression quality was assessed with a Skill Reporting Laerdal Resusci-Anne manikin. Quality variables were: the number and rate of compressions, compression depth, release, land marking, and overall aggregate quality score. Participant feedback was collected using the Borg Scale of Perceived Exertion, and compression difficulty using a zero-to-ten scale. Furthermore, we solicited open-ended descriptive responses. Results: The average overall quality score was 63% for conventional compressions versus 79% for Koch compressions (p = 0.04). On average, the Koch compression method increased compression depth by 5 mm (95% CI 4.3 to 5.7) and the proportion of compressions at the correct depth by 17% (95% CI 7.55 to 26.45), although these were not statistically significant. Correct release and land marking showed no statistically significant difference between techniques. Koch compressions resulted in statistically significant reductions in physical exertion and difficulty (p < 0.001). Qualitative feedback described modified compressions as easier and more sustainable. Conclusions: In a height-restricted aeromedical helicopter, the average overall quality score improved using Koch compressions, although the mean rate, mean depth, correct release and land marking were found to be similar between techniques. Qualitative feedback described Koch compressions as easier and more sustainable. In settings where the compressor is affected by reduced overhead working height, Koch compressions may be an advisable alternative.

Physiological demands of quality cardiopulmonary resuscitation performed at simulated 3250 meters high.

AIM: To analyse the effect of oxygen fraction reduction (O2 14%, equivalent to 3250 m) on Q-CPR and rescuers' physiological demands. METHODOLOGY: A quasi-experimental study was carried out in a sample of 9 Q-CPR proficient health care professionals. Participants, in teams of 2 people, performed 10 min CPR on a Laerdal ResusciAnne mannequin (30:2 compression/ventilation ratio and alternating roles between rescuers every 2 min) in two simulated settings: T21-CPR at sea level (FiO2 of 21%) and T14 - CPR at 3250 m altitude (FiO2 of 14%). Effort self-perception was rated from 0 (no effort) to 10 (maximum demand) points. RESULTS: Quality of chest compressions was good and similar in both conditions (T21 vs T14). However, the percentage of ventilations with adequate tidal volume was lower in altitude than at sea level conditions (35.9 ± 25.2% vs. 54.7 ± 23.2%, p = 0.035). The subjective perception of effort was significantly higher at simulated altitude (5 ± 2) than at sea level (3 ± 2) (p = 0.038). Maximum heart rate during the tests was similar in both conditions; however, mean oxygen saturation was significantly lower in altitude conditions (90.5 ± 2.5% vs. 99.3 ± 0.5%, p < 0.001). CONCLUSION: Although performing CPR under simulated hypoxic altitude conditions significantly increases the physiological demands and subjective feeling of tiredness compared to sea level CPR, trained rescuers are able to deliver good Q-CPR in such conditions, at least in the first 10 min of resuscitation.

RESCUE transesophageal echocardiography for monitoring of mechanical chest compressions and guidance for extracorporeal cardiopulmonary resuscitation cannulation in refractory cardiac arrest.

There is a growing interest in using point-of-care transesophageal echocardiography (TEE) during cardiac arrest. TEE is effective at identifying the etiology of sudden cardiovascular collapse and guiding management during the resuscitation. In selected patients with refractory cardiac arrest, extracorporeal cardiopulmonary resuscitation (ECPR) can be considered. ECPR requires percutaneous vascular access for the implantation of veno-arterial extracorporeal membrane oxygenation circuit. We present a case of prolonged cardiac arrest in which rescue TEE was pivotal in narrowing the differential diagnosis, monitoring of mechanical chest compression performance, and guiding cannulation for ECPR.

Confirming the Clinical Safety and Feasibility of a Bundled Methodology to Improve Cardiopulmonary Resuscitation Involving a Head-Up/Torso-Up Chest Compression Technique.

OBJECTIVES: Combined with devices that enhance venous return out of the brain and into the thorax, preclinical outcomes are improved significantly using a synergistic bundled approach involving mild elevation of the head and chest during cardiopulmonary resuscitation. The objective here was to confirm clinical safety/feasibility of this bundled approach including use of mechanical cardiopulmonary resuscitation provided at a head-up angle. DESIGN: Quarterly tracking of the frequency of successful resuscitation before, during, and after the clinical introduction of a bundled head-up/torso-up cardiopulmonary resuscitation strategy. SETTING: 9-1-1 response system for a culturally diverse, geographically expansive, populous jurisdiction. PATIENTS: All 2,322 consecutive out-of-hospital cardiac arrest cases (all presenting cardiac rhythms) were followed over 3.5 years (January 1, 2014, to June 30, 2017). INTERVENTIONS: In 2014, 9-1-1 crews used LUCAS (Physio-Control Corporation, Redmond, WA) mechanical cardiopulmonary resuscitation and impedance threshold devices for out-of-hospital cardiac arrest. After April 2015, they also 1) applied oxygen but deferred positive pressure ventilation several minutes, 2) solidified a pit-crew approach for rapid LUCAS placement, and 3) subsequently placed the patient in a reverse Trendelenburg position (~20°). MEASUREMENTS AND MAIN RESULTS: No problems were observed with head-up/torso-up positioning (n = 1,489), but resuscitation rates rose significantly during the transition period (April to June 2015) with an ensuing sustained doubling of those rates over the next 2 years (mean, 34.22%; range, 29.76-39.42%; n = 1,356 vs 17.87%; range, 14.81-20.13%, for 806 patients treated prior to the transition; p < 0.0001). Outcomes improved across all subgroups. Response intervals, clinical presentations and indications for attempting resuscitation remained unchanged. Resuscitation rates in 2015-2017 remained proportional to neurologically intact survival (~35-40%) wherever tracked. CONCLUSIONS: The head-up/torso-up cardiopulmonary resuscitation bundle was feasible and associated with an immediate, steady rise in resuscitation rates during implementation followed by a sustained doubling of the number of out-of-hospital cardiac arrest patients being resuscitated. These findings make a compelling case that this bundled technique will improve out-of-hospital cardiac arrest outcomes significantly in other clinical evaluations.

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

BACKGROUND: 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). CONCLUSIONS: 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.

Transesophageal Echocardiography During Cardiopulmonary Resuscitation Is Associated With Shorter Compression Pauses Compared With Transthoracic Echocardiography.

STUDY OBJECTIVE: Point-of-care ultrasonography provides diagnostic information in addition to visual pulse checks during cardiopulmonary resuscitation (CPR). The most commonly used modality, transthoracic echocardiography, has unfortunately been repeatedly associated with prolonged pauses in chest compressions, which correlate with worsened neurologic outcomes. Unlike transthoracic echocardiography, transesophageal echocardiography does not require cessation of compressions for adequate imaging and provides the diagnostic benefit of point-of-care ultrasonography. To assess a benefit of transesophageal echocardiography, we compare the duration of chest compression pauses between transesophageal echocardiography, transthoracic echocardiography, and manual pulse checks on video recordings of cardiac arrest resuscitations. METHODS: We analyzed 139 pulse check CPR pauses among 25 patients during cardiac arrest. RESULTS: Transesophageal echocardiography provided the shortest mean pulse check duration (9 seconds [95% confidence interval {CI} 5 to 12 seconds]). Mean pulse check duration with transthoracic echocardiography was 19 seconds (95% CI 16 to 22 seconds), and it was 11 seconds (95% CI 8 to 14 seconds) with manual checks. Intraclass correlation coefficient between abstractors for a portion of individual and average times was 0.99 and 0.99, respectively (P<.001 for both). CONCLUSION: Our study suggests that pulse check times with transesophageal echocardiography are shorter versus with transthoracic echocardiography for ED point-of-care ultrasonography during cardiac arrest resuscitations, and further emphasizes the need for careful attention to compression pause duration when using transthoracic echocardiography for point-of-care ultrasonography during ED cardiac arrest resuscitations.

Use of Tandem Perimortem Cesarean Section and Open-Chest Cardiac Massage in the Resuscitation of Peripartum Cardiomyopathy Cardiac Arrest.

Cardiac arrest and resuscitation of the pregnant woman at gestational term is rare. Depending on the circumstances of cardiac arrest and its timing, options are limited for allowing successful resuscitation of both mother and neonate. Herein, we describe the use of tandem perimortem cesarean section and thoracotomy for open-chest cardiac massage in a young woman with newly diagnosed peripartum cardiomyopathy. We used goal-directed resuscitation including diagnostic ultrasonography and capnography to assist in decision making and successfully resuscitated both mother and neonate to hospital discharge without discernable long-term complications.

Effect of metronome guidance on infant cardiopulmonary resuscitation.

This study was conducted to investigate the effect of metronome guidance on the performance of infant cardiopulmonary resuscitation (CPR). A total of 36 medical doctors conducted a 2-min single rescuer CPR with the two-finger technique (TFT) or two-thumb encircling hands technique (TT) on an infant manikin without metronome guidance (baseline test). After completing the baseline test, the participants were assigned to either a "guidance group" or "non-guidance group." The guidance group performed CPR with a high-pitched sound at 110 beats/min from a metronome (test 2), while the non-guidance group performed 2-min CPR without metronome guidance (test 1). Comparison between the results of tests 1 and 2 showed that the ratio of adequate chest compression rate was significantly different in both the TFT (73% [34-93] vs. 98% [95-99], P < 0.001) and the TT (53% [32-79] vs. 99% [98-100], P = 0.010). Other parameters including average depth and the ratio of adequate depth were not significantly different between tests 1 and 2 in both the TFT and TT.Conclusion: Metronome guidance improves the adequacy of chest compression rate during infant CPR without affecting chest compression depth in both the TFT and TT.Trial registration: Clinical Research Information Service, KCT0002735 What is Known: • The rate of chest compressions can be optimized by the use of metronome guidance in pediatric cardiopulmonary resuscitation (CPR). • An adverse effect of deteriorating chest compression depth was found while using a metronome guidance during adult CPR simulations. What is New: • The metronome guidance improved the adequacy of the chest compression rate during infant CPR without affecting other parameters including average depth and the ratio of adequate depth in both the two-finger chest compression technique and two-thumb encircling hand technique.

Two new chest compression methods might challenge the standard in a simulated infant model.

Paediatric cardiorespiratory arrest is a rare event that requires a fast, quality intervention. High-quality chest compressions are an essential prognostic factor. The aim of this prospective, randomized and crossover study in infant manikin 2-min cardiorespiratory resuscitation scenario is to quantitatively compare the quality of the currently recommended method in infants (two-thumb-encircling hand techniques) with two new methods (the new two-thumb and the knocking-fingers techniques) using a 15:2 compression-to-ventilation ratio. Ten qualified health professionals were recruited. Variables analysed were mean rate and the ratio of compressions in the recommended rate range, mean depth and the ratio of compressions within the depth range recommendations, ratio of compressions with adequate chest release and ratio of compressions performed with the fingers in the correct position. Ratios of correct compressions for depth, rate, chest release and hand position were always above 70% regardless of the technique used. Reached mean depth and mean rate were similar to the 3 techniques. No statistically significant differences were found in any of the variables analysed.Conclusion: In an infant manikin, professionals are able to perform chest compressions with the new techniques with similar quality to that obtained with the standard method. What is Known: • Quality chest compressions are an essential prognostic factor in paediatric cardiorespiratory arrest. • It has been reported poor results when studied cardiorespiratory resuscitation quality in infants applying the recommended methods. What is New: • In a simulated scenario, quality of chest compressions performed with two new techniques (nTTT and KF) is similar to that obtained with the currently recommended method (TTHT).