3:1 Compression to ventilation ratio versus continuous chest compression with asynchronous ventilation in a porcine model of neonatal resuscitation

Objective

In contrast to the resuscitation guidelines of children and adults, guidelines on neonatal resuscitation recommend synchronized 90 chest compressions with 30 manual inflations (3:1) per minute in newborn infants. The study aimed to determine if chest compression with asynchronous ventilation improves the recovery of bradycardic asphyxiated newborn piglets compared to 3:1 Compression:Ventilation cardiopulmonary resuscitation (CPR).

Intervention and measurements

Term newborn piglets (n = 8/group) were anesthetized, intubated, instrumented and exposed to 45-min normocapnic hypoxia followed by asphyxia. Protocolized resuscitation was initiated when heart rate decreased to 25% of baseline. Piglets were randomized to receive resuscitation with either 3:1 compressions to ventilations (3:1 C:V CPR group) or chest compressions with asynchronous ventilations (CCaV) or sham. Continuous respiratory parameters (Respironics NM3^®), cardiac output, mean systemic and pulmonary artery pressures, and regional blood flows were measured.

Main results

Piglets in 3:1 C:V CPR and CCaV CPR groups had similar time to return of spontaneous circulation, survival rates, hemodynamic and respiratory parameters during CPR. The systemic and regional hemodynamic recovery in the subsequent 4 h was similar in both groups and significantly lower compared to sham-operated piglets.

Conclusion

Newborn piglets resuscitated by CCaV had similar return of spontaneous circulation, survival, and hemodynamic recovery compared to those piglets resuscitated by 3:1 Compression:Ventilation ratio.     

CPR-related injuries after manual or mechanical chest compressions with the LUCAS™ device: A multicentre study of victims after unsuccessful resuscitation

Aim

The reported incidence of injuries due to cardiopulmonary resuscitation using manual chest compressions (manual CPR) varies greatly. Our aim was to elucidate the incidence of CPR-related injuries by manual chest compressions compared to mechanical chest compressions with the LUCAS device (mechanical CPR) in non-survivors after out-of-hospital cardiac arrest.

Methods

In this prospective multicentre trial, including 222 patients (83 manual CPR/139 mechanical CPR), autopsies were conducted after unsuccessful CPR and the results were evaluated according to a specified protocol.

Results

Among the patients included, 75.9% in the manual CPR group and 91.4% in the mechanical CPR group (p = 0.002) displayed CPR-related injuries. Sternal fractures were present in 54.2% of the patients in the manual CPR group and in 58.3% in the mechanical CPR group (p = 0.56). Of the patients in the manual CPR group, there were 64.6% with at least one rib fracture versus 78.8% in the mechanical CPR group (p = 0.02). The median number of rib fractures among patients with rib fractures was 7 in the manual CPR group and 6 in the mechanical CPR group. No CPR-related injury was considered to be the cause of death.

Conclusion

In patients with unsuccessful CPR after out-of-hospital cardiac arrest, rib fractures were more frequent after mechanical CPR but there was no difference in the incidence of sternal fractures. No injury was deemed fatal by the pathologist.     

Quality of CPR performed by trained bystanders with optimized pre-arrival instructions

Objective

Telephone-CPR (T-CPR) can increase initiation of bystander CPR. We wanted to study if quality oriented continuous T-CPR would improve CPR performance vs. standard T-CPR.

Method

Ninety-five trained rescuers aged 22–69 were randomized to standard T-CPR or experimental continuous T-CPR (comprises continuous instructions, questions and encouragement). They were instructed to perform 10 min of chest compressions-only on a manikin, which recorded CPR performance in a small, confined kitchen. Three video-cameras captured algorithm time data, CPR technique and communication. Demography and training experience were captured during debriefing.

Results

Participants receiving continuous T-CPR delivered significantly more chest compressions (median 1000 vs. 870 compressions, p = 0.014) and compressed more frequently to a compression rate between 90 and 120 min⁻¹ (median 87% vs. 60% of compressions, p < 0.001), compared to those receiving standard T-CPR. This also resulted in less time without compressions after CPR had started (median 12 s vs. 64 s, p < 0.001), but longer time interval from initiating contact with dispatcher to first chest compression (median 144 s vs. 84 s, p < 0.001). There was no difference in chest compression depth (mean 47 mm vs. 48 mm, p = 0.90) or in demography, education and previous CPR training between the groups.

Conclusion

In our simulated scenario with CPR trained lay rescuers, experimental continuous T-CPR gave better chest compression rate and less hands-off time during CPR, but resulted in delayed time to first chest compression compared to standard T-CPR instructions.     

Deeper chest compression – More complications for cardiac arrest patients?

Aim of the study

Sternal and rib fractures are frequent complications caused by chest compressions during cardiopulmonary resuscitation (CPR). This study aimed to investigate the potential association of CPR-related thoracic and abdominal injuries and compression depth measured with an accelerometer.

Methods

We analysed the autopsy records, CT scans or chest radiographs of 170 adult patients, suffering in-hospital cardiac arrest at the Tampere University Hospital during the period 2009–2011 to investigate possible association of chest compressions and iatrogenic injuries. The quality of manual compressions during CPR was recorded on a Philips, HeartStart MRx Q-CPR™-defibrillator.

Results

Patients were 110 males and 60 females. Injuries were found in 36% of male and 23% of female patients. Among male patients CPR-related injuries were associated with deeper mean – and peak compression depths (p < 0.05). No such association was observed in women. The frequency of injuries in mean compression depth categories <5, 5–6 and >6 cm, was 28%, 27% and 49% (p = 0.06). Of all patients 27% sustained rib fractures, 11% sternal fracture and eight patients had haematomas/ruptures in the myocardium. In addition, we observed one laceration of the stomach without bleeding, one ruptured spleen, one mediastinal haemorrhage and two pneumothoraxes.

Conclusion

The number of iatrogenic injuries in male patients was associated with chest compressions during cardiopulmonary resuscitation increased as the measured compression depth exceeded 6 cm. While there is an increased risk of complications with deeper compressions it is important to realize that the injuries were by and large not fatal.     

The impact of airway management on quality of cardiopulmonary resuscitation: An observational study in patients during cardiac arrest

Background

Minimising interruptions in chest compressions is associated with improved survival from cardiac arrest. Current in-hospital guidelines recommend continuous chest compressions after the airway is secured on the premise that this will reduce no flow time. The aim of this study was to determine the effect of advanced airway use on the no flow ratio and other measures of CPR quality.

Methods

Consecutive adult patients who sustained an in-hospital cardiac arrest were enrolled in this prospective observational study. The quality of CPR was measured using the Q-CPR device (Phillips, UK) before and after an advanced airway device (endotracheal tube [ET] or laryngeal mask airway [LMA]) was inserted. Patients receiving only bag-mask ventilation were used as the control cohort. The primary outcome was no flow ratio (NFR). Secondary outcomes were chest compression rate, depth, compressions too shallow, compressions with leaning, ventilation rate, inflation time, change in impedance and time required to successfully insert airway device.

Results

One hundred patients were enrolled in the study (2008–2011). Endotracheal tube and LMA placement took similar durations (median 15.8 s (IQR 6.8–19.4) vs LMA median 8.0 s (IQR 5.5–15.9), p = 0.1). The use of an advanced airway was associated with improved no flow ratios (endotracheal tube placement (n = 50) improved NFR from baseline median 0.24 IQR 0.17–0.40) to 0.15 to (IQR 0.09–0.28), p = 0.012; LMA (n = 25) from median 0.28 (IQR 0.23–0.40) to 0.13 (IQR 0.11– 0.19), p = 0.0001). There was no change in NFR in patients managed solely with bag valve mask (BVM) (n = 25) (median 0.29 (IQR 0.18–0.59) vs median 0.26 (IQR 0.12–0.37), p = 0.888). There was no significant difference in time taken to successfully insert the airway device between the two groups.

Conclusion

The use of an advanced airway (ETT or LMA) during in-hospital cardiac arrest was associated with improved no flow ratio. Further studies are required to determine the effect of airway devices on overall patient outcomes.     

A randomised control trial of prompt and feedback devices and their impact on quality of chest compressions—A simulation study

Aim

This study aims to compare the effect of three CPR prompt and feedback devices on quality of chest compressions amongst healthcare providers.

Methods

A single blinded, randomised controlled trial compared a pressure sensor/metronome device (CPREzy™), an accelerometer device (Phillips Q-CPR) and simple metronome on the quality of chest compressions on a manikin by trained rescuers. The primary outcome was compression depth. Secondary outcomes were compression rate, proportion of chest compressions with inadequate depth, incomplete release and user satisfaction.

Results

The pressure sensor device improved compression depth (37.24–43.64 mm, p = 0.02), the accelerometer device decreased chest compression depth (37.38–33.19 mm, p = 0.04) whilst the metronome had no effect (39.88 mm vs 40.64 mm, p = 0.802). Compression rate fell with all devices (pressure sensor device 114.68–98.84 min⁻¹, p = 0.001, accelerometer 112.04–102.92 min⁻¹, p = 0.072 and metronome 108.24 min⁻¹ vs 99.36 min⁻¹, p = 0.009). The pressure sensor feedback device reduced the proportion of compressions with inadequate depth (0.52 vs 0.24, p = 0.013) whilst the accelerometer device and metronome did not have a statistically significant effect. Incomplete release of compressions was common, but unaffected by the CPR feedback devices. Users preferred the accelerometer and metronome devices over the pressure sensor device. A post hoc study showed that de-activating the voice prompt on the accelerometer device prevented the deterioration in compression quality seen in the main study.

Conclusion

CPR feedback devices vary in their ability to improve performance. In this study the pressure sensor device improved compression depth, whilst the accelerometer device reduced it and metronome had no effect.     

A pilot study of mechanical chest compressions with the LUCAS™ device in cardiopulmonary resuscitation

Aim

The LUCAS™ device has been shown to improve organ perfusion during cardiac arrest in experimental studies. In this pilot study the aim was to compare short-term survival between cardiopulmonary resuscitation (CPR) performed with mechanical chest compressions using the LUCAS™ device and CPR performed with manual chest compressions. The intention was to use the results for power calculation in a larger randomised multicentre trial.

Methods

In a prospective pilot study, from February 1, 2005, to April 1, 2007, 149 patients with out-of hospital cardiac arrest in two Swedish cities were randomised to mechanical chest compressions or standard CPR with manual chest compressions.

Results

After exclusion, the LUCAS and the manual groups contained 75 and 73 patients, respectively. In the LUCAS and manual groups, spontaneous circulation with a palpable pulse returned in 30 and 23 patients (p = 0.30), spontaneous circulation with blood pressure above 80/50 mmHg remained for at least 5 min in 23 and 19 patients (p = 0.59), the number of patients hospitalised alive >4 h were 18 and 15 (p = 0.69), and the number discharged, alive 6 and 7 (p = 0.78), respectively.

Conclusions

In this pilot study of out-of-hospital cardiac arrest patients we found no difference in early survival between CPR performed with mechanical chest compression with the LUCAS™ device and CPR with manual chest compressions. Data have been used for power calculation in a forthcoming multicentre trial.     

Feasibility of automated rhythm assessment in chest compression pauses during cardiopulmonary resuscitation

Aim

To demonstrate the feasibility of doing a reliable rhythm analysis in the chest compression pauses (e.g. pauses for two ventilations) during cardiopulmonary resuscitation (CPR).

Methods

We extracted 110 shockable and 466 nonshockable segments from 235 out-of-hospital cardiac arrest episodes. Pauses in chest compressions were already annotated in the episodes. We classified pauses as ventilation or non-ventilation pause using the transthoracic impedance. A high-temporal resolution shock advice algorithm (SAA) that gives a shock/no-shock decision in 3 s was launched once for every pause longer than 3 s. The sensitivity and specificity of the SAA for the analyses during the pauses were computed.

Results

We identified 4476 pauses, 3263 were ventilation pauses and 2183 had two ventilations. The median of the mean duration per segment of all pauses and of pauses with two ventilations were 6.1 s (4.9–7.5 s) and 5.1 s (4.2–6.4 s), respectively. A total of 91.8% of the pauses and 95.3% of the pauses with two ventilations were long enough to launch the SAA. The overall sensitivity and specificity were 95.8% (90% low one-sided CI, 94.3%) and 96.8% (CI, 96.2%), respectively. There were no significant differences between the sensitivities (P = 0.84) and the specificities (P = 0.18) for the ventilation and the non-ventilation pauses.

Conclusion

Chest compression pauses are frequent and of sufficient duration to launch a high-temporal resolution SAA. During these pauses rhythm analysis was reliable. Pre-shock pauses could be minimised by analysing the rhythm during ventilation pauses when CPR is delivered at 30:2 compression:ventilation ratio.     

Two-thumb technique is superior to two-finger technique during lone rescuer infant manikin CPR

Objective

Infant CPR guidelines recommend two-finger chest compression with a lone rescuer and two-thumb with two rescuers. Two-thumb provides better chest compression but is perceived to be associated with increased ventilation hands-off time. We hypothesized that lone rescuer two-thumb CPR is associated with increased ventilation cycle time, decreased ventilation quality and fewer chest compressions compared to two-finger CPR in an infant manikin model.

Design

Crossover observational study randomizing 34 healthcare providers to perform 2 min CPR at a compression rate of 100 min⁻¹ using a 30:2 compression:ventilation ratio comparing two-thumb vs. two-finger techniques.

Methods

A Laerdal™ Baby ALS Trainer manikin was modified to digitally record compression rate, compression depth and compression pressure and ventilation cycle time (two mouth-to-mouth breaths). Manikin chest rise with breaths was video recorded and later reviewed by two blinded CPR instructors for percent effective breaths. Data (mean ± SD) were analyzed using a two-tailed paired t-test. Significance was defined qualitatively as p ≤ 0.05.

Result

Mean % effective breaths were 90 ± 18.6% in two-thumb and 88.9 ± 21.1% in two-finger, p = 0.65. Mean time (s) to deliver two mouth-to-mouth breaths was 7.6 ± 1.6 in two-thumb and 7.0 ± 1.5 in two-finger, p < 0.0001. Mean delivered compressions per minute were 87 ± 11 in two-thumb and 92 ± 12 in two-finger, p = 0.0005. Two-thumb resulted in significantly higher compression depth and compression pressure compared to the two-finger technique.

Conclusion

Healthcare providers required 0.6 s longer time to deliver two breaths during two-thumb lone rescuer infant CPR, but there was no significant difference in percent effective breaths delivered between the two techniques. Two-thumb CPR had 4 fewer delivered compressions per minute, which may be offset by far more effective compression depth and compression pressure compared to two-finger technique.     

Beyond the pre-shock pause: the effect of prehospital defibrillation mode on CPR interruptions and return of spontaneous circulation

Aims

The pattern of interruptions to chest compressions in pre-hospital cardiac arrests in Wellington, New Zealand, was examined prospectively to determine whether the mode of defibrillation chosen by paramedics influenced interruptions, shock success and the return of spontaneous circulation (ROSC).

Methods

A prospective observational cohort study of 44 adult cardiac arrests in which 203 shocks were administered by Wellington Free Ambulance (WFA) paramedics was undertaken to compare Code-stat^® electronic records from Medtronic^® Lifepak 12 and Lifepak 15 defibrillators used in semi-automated (AED) or manual mode. Interruptions during the 30 s prior to shock delivery as well as pre-shock and post-shock pauses were calculated. Shock success and ROSC were the outcome measures.

Results

Pre-shock pauses were shorter in manual mode (median 3 s, IQR 2–5) versus AED mode (median 4 s, IQR 3–6; p = 0.003). Interruptions of CPR in the 30 s prior to shock delivery were also shorter in manual mode (median 7 s, IQR 4–11) versus AED mode (median 14 s, IQR 12–16; p = <0.001). Shock success rates and post-shock pauses were not statistically different between modes. ROSC was significantly higher in manual mode (18.49%) versus AED mode (8.33%, p = 0.042).

Conclusion

When paramedics used the defibrillator in manual mode as compared to AED mode, interruptions to CPR during the 30 s prior to shock delivery were significantly reduced and pre-shock pauses were also shorter. This was associated with increased ROSC. Manual defibrillation should be the preferred option for appropriately trained paramedics. Training in this locality has been changed accordingly.     

Continuous mechanical chest compression during in-hospital cardiopulmonary resuscitation of patients with pulseless electrical activity

Survival after in-hospital pulseless electrical activity (PEA) cardiac arrest is poor and has not changed during the last 10 years. Effective chest compressions may improve survival after PEA. We investigated whether a mechanical device (LUCAS™-CPR) can ensure chest compressions during cardiac arrest according to guidelines and without interruption during transport, diagnostic procedures and in the catheter laboratory.

Methods

We studied mechanical chest compression in 28 patients with PEA (pulmonary embolism (PE) n = 14; cardiogenic shock/acute myocardial infarction; n = 9; severe hyperkalemia; n = 2; sustained ventricular arrhythmias/electrical storm; n = 3) in a university hospital setting.

Results

During or immediately after CPR, 21 patients underwent coronary angiography and or pulmonary angiography. Successful return of a spontaneous circulation (ROSC) was achieved in 27 out of the 28 patients. Ten patients died within the first hour and three patients died within 24 h after CPR. A total of 14 patients survived and were discharged from hospital (13 without significant neurological deficit). Interestingly, six patients with PE did not have thrombolytic therapy due to contraindications. CT-angiography findings in these patients showed fragmentation of the thrombus suggesting thrombus breakdown as an additional effect of mechanical chest compressions. No patients exhibited any life-threatening device-related complications.

Conclusion

Continuous chest compression with an automatic mechanical device is feasible, safe, and might improve outcomes after in-hospital-resuscitation of PEA. Patients with PE may benefit from effective continuous chest compression, probably due to thrombus fragmentation and increased pulmonary artery blood flow.     

Motion detection technology as a tool for cardiopulmonary resuscitation (CPR) quality training: A randomised crossover mannequin pilot study

Introduction

Outcome after cardiac arrest is dependent on the quality of chest compressions (CC). A great number of devices have been developed to provide guidance during CPR. The present study evaluates a new CPR feedback system (Mini-VREM: Mini-Virtual Reality Enhanced Mannequin) designed to improve CC during training.

Methods

Mini-VREM system consists of a Kinect^® (Microsoft, Redmond, WA, USA) motion sensing device and specifically developed software to provide audio–visual feedback. Mini-VREM was connected to a commercially available mannequin (Laerdal Medical, Stavanger, Norway). Eighty trainees (healthcare professionals and lay people) volunteered in this randomised crossover pilot study. All subjects performed a 2 min CC trial, 1 h pause and a second 2 min CC trial. The first group (FB/NFB, n = 40) performed CC with Mini-VREM feedback (FB) followed by CC without feedback (NFB). The second group (NFB/FB, n = 40) performed vice versa. Primary endpoints: adequate compression (compression rate between 100 and 120 min⁻¹ and compression depth between 50 and 60 mm); compressions rate within 100–120 min⁻¹; compressions depth within 50–60 mm.

Results

When compared to the performance without feedback, with Mini-VREM feedback compressions were more adequate (FB 35.78% vs. NFB 7.27%, p < 0.001) and more compressions achieved target rate (FB 72.04% vs. 31.42%, p < 0.001) and target depth (FB 47.34% vs. 24.87%, p = 0.002). The participants perceived the system to be easy to use with effective feedback.

Conclusions

The Mini-VREM system was able to improve significantly the CC performance by healthcare professionals and by lay people in a simulated CA scenario, in terms of compression rate and depth.     

Animation-assisted CPRII program as a reminder tool in achieving effective one-person-CPR performance

Objective

The objective of this study is to compare the skill retention of two groups of lay persons, six months after their last CPR training. The intervention group was provided with animation-assisted CPRII (AA-CPRII) instruction on their cellular phones, and the control group had nothing but what they learned from their previous training.

Methods

This study was a single blind randomized controlled trial. The participants’ last CPR trainings were held at least six months ago. We revised our CPR animation for on-site CPR instruction content emphasizing importance of chest compression. Participants were randomized into two groups, the AA-CPRII group (n = 42) and the control group (n = 38). Both groups performed three cycles of CPR and their performances were video recorded. These video clips were assessed by three evaluators using a checklist. The psychomotor skills were evaluated using the Resusci^®Anne SkillReporter™.

Results

Using the 30-point scoring checklist, the AA-CPRII group had a significantly better score compared to the control group (p < 0.001). Psychomotor skills evaluated with the AA-CPRII group demonstrated better performance in hand positioning (p = 0.025), compression depth (p = 0.035) and compression rate (p < 0.001) than the control group.

Conclusion

The AA-CPRII group resulted in better checklist scores, including chest compression rate, depth and hand positioning. Animation-assisted CPR could be used as a reminder tool in achieving effective one-person-CPR performance. By installing the CPR instruction on cellular phones and having taught them CPR with it during the training enabled participants to perform better CPR.     

Quality of chest compressions during continuous CPR; comparison between chest compression-only CPR and conventional CPR

Objectives

This study aimed to compare the time-dependent deterioration of chest compressions between chest compression-only cardiopulmonary resuscitation (CPR) and conventional CPR.

Methods

This study involved 106 and 107 participants randomly assigned to chest compression-only CPR training and conventional CPR training, respectively. Immediately after training, participants were asked to perform CPR for 2 min and the quality of their CPR skills were evaluated. The number of chest compressions in total and those with appropriate depth were counted every 20-s CPR period from the start of CPR. The primary outcome was the CPR quality index calculated as the proportion of chest compressions with appropriate depth among total chest compressions.

Results

The total number of chest compressions remained stable over time both in the chest compression-only and the conventional CPR groups. The CPR quality index, however, decreased from 86.6 ± 25.0 to 58.2 ± 36.9 in the chest compression-only CPR group from 0-20 s through 61-80 s. The reduction was greater than in the conventional CPR group (85.9 ± 25.5 to 74.3 ± 34.0). The difference in the CPR quality index reached statistical significance (p = 0.003) at 61-80 s period.

Conclusions

Chest compressions with appropriate depth decreased more rapidly during chest compression-only CPR than conventional CPR. We recommend that CPR providers change their roles every 1 min to maintain the quality of chest compressions during chest compression-only CPR. (UMIN-CTR C0000000321)     

Detection of a spontaneous pulse in photoplethysmograms during automated cardiopulmonary resuscitation in a porcine model

Introduction

Reliable, non-invasive detection of return of spontaneous circulation (ROSC) with minimal interruptions to chest compressions would be valuable for high-quality cardiopulmonary resuscitation (CPR). We investigated the potential of photoplethysmography (PPG) to detect the presence of a spontaneous pulse during automated CPR in an animal study.

Methods

Twelve anesthetized pigs were instrumented to monitor circulatory and respiratory parameters. Here we present the simultaneously recorded PPG and arterial blood pressure (ABP) signals. Ventricular fibrillation was induced, followed by 20 min of automated CPR and subsequent defibrillation. After defibrillation, pediatric-guidelines-style life support was given in cycles of 2 min. PPG and ABP waveforms were recorded during all stages of the protocol. Raw PPG waveforms were acquired with a custom-built photoplethysmograph controlling a commercial reflectance pulse oximetry probe attached to the nose. ABP was measured in the aorta.

Results

In nine animals ROSC was achieved. Throughout the protocol, PPG and ABP frequency content showed strong resemblance. We demonstrate that (1) the PPG waveform allows for the detection of a spontaneous pulse during ventilation pauses, and that (2) frequency analysis of the PPG waveform allows for the detection of a spontaneous pulse and the determination of the pulse rate, even during ongoing chest compressions, if the pulse and compression rates are sufficiently distinct.

Conclusions

These results demonstrate the potential of PPG as a non-invasive means to detect pulse presence or absence, as well as pulse rate during CPR.     

Ability of code leaders to recall CPR quality errors during the resuscitation of older children and adolescents

Aim

Performance of high quality CPR is associated with improved resuscitation outcomes. This study investigates code leader ability to recall CPR error during post-event interviews when CPR recording/audiovisual feedback-enabled defibrillators are deployed.

Patients and methods

Physician code leaders were interviewed within 24 h of 44 in-hospital pediatric cardiac arrests to assess their ability to recall if CPR error occurred during the event. Actual CPR quality was assessed using quantitative recording/feedback-enabled defibrillators. CPR error was defined as an overall average event chest compression (CC) rate <95/min, depth <38 mm, ventilation rate >10/min, or any interruptions in CPR >10 s. We hypothesized that code leaders would recall error when it actually occurred ≥75% of the time when assisted by audiovisual alerts from a CPR recording feedback-enabled defibrillators (analysis by χ²).

Results

810 min from 44 cardiac arrest events yielded 40 complete data sets (actual and interview); ventilation data was available in 24. Actual CPR error was present in 3/40 events for rate, 4/40 for depth, 32/40 for interruptions >10 s, and 17/24 for ventilation frequency. In post-event interviews, code leaders recalled these errors in 0/3 (0%) for rate, 0/4 (0%) for depth, and 19/32 (59%) for interruptions >10 s. Code leaders recalled these CPR quality errors less than 75% of the time for rate (p = 0.06), for depth (p < 0.01), and for CPR interruption (p = 0.04). Quantification of errors not recalled: missed rate error median = 94 CC/min (IQR 93–95), missed depth error median = 36 mm (IQR 35.5–36.5), missed CPR interruption >10 s median = 18 s (IQR 14.4–28.9). Code leaders did recall the presence of excessive ventilation in 16/17 (94%) of events (p = 0.07).

Conclusion

Despite assistance by CPR recording/feedback-enabled defibrillators, pediatric code leaders fail to recall important CPR quality errors for CC rate, depth, and interruptions during post-cardiac arrest interviews.     

Real-time feedback can improve infant manikin cardiopulmonary resuscitation by up to 79%—A randomised controlled trial

Setting

European and Advanced Paediatric Life Support training courses.

Participants

Sixty-nine certified CPR providers.

Interventions

CPR providers were randomly allocated to a ‘no-feedback’ or ‘feedback’ group, performing two-thumb and two-finger chest compressions on a “physiological”, instrumented resuscitation manikin. Baseline data was recorded without feedback, before chest compressions were repeated with one group receiving feedback.

Main outcome measures

Indices were calculated that defined chest compression quality, based upon comparison of the chest wall displacement to the targets of four, internationally recommended parameters: chest compression depth, release force, chest compression rate and compression duty cycle.

Results

Baseline data were consistent with other studies, with <1% of chest compressions performed by providers simultaneously achieving the target of the four internationally recommended parameters. During the ‘experimental’ phase, 34 CPR providers benefitted from the provision of ‘real-time’ feedback which, on analysis, coincided with a statistical improvement in compression rate, depth and duty cycle quality across both compression techniques (all measures: p < 0.001). Feedback enabled providers to simultaneously achieve the four targets in 75% (two-finger) and 80% (two-thumb) of chest compressions.

Conclusions

Real-time feedback produced a dramatic increase in the quality of chest compression (i.e. from <1% to 75–80%). If these results transfer to a clinical scenario this technology could, for the first time, support providers in consistently performing accurate chest compressions during infant CPR and thus potentially improving clinical outcomes.     

Performance of chest compressions by laypersons during the Public Access Defibrillation Trial

Background

Increasing evidence indicates that health professionals often may not achieve guideline standards for cardiopulmonary resuscitation (CPR). Little is known about layperson CPR performance.

Methods

The investigation was a retrospective cohort study of cardiac arrest patients treated by layperson CPR and one model of automated external defibrillator (AED) as part of the Public Access Defibrillation Trial (n = 26). CPR was measured using software that integrates the event log, ECG signal, and thoracic impedance signal. We assessed chest compression fraction (proportion of attempted resuscitation spent performing chest compressions), prompted compression fraction (proportion of attempted resuscitation spent performing compressions during AED-prompted periods), compression rate, and compressions per minute.

Results

Of the 26 cases, 13 presented with ventricular fibrillation and 13 with nonshockable rhythms. Overall, during the period when patients did not have spontaneous circulation, the median chest compression fraction was 34% (IQR 17-48%), median prompted chest compression fraction was 49% (IQR 30-66%), and the median chest compression rate was 96/min (IQR 90-110/min). Taken together, the median chest compression delivered per minute among all arrests was 29 (IQR 20-42). CPR characteristics differed according to initial rhythm: median chest compression per minute was 20 (IQR 13-29) among ventricular fibrillation and 42 (IQR 28-47) among nonshockable rhythms (p = 0.003).

Conclusions

In this study of trained laypersons, CPR varied substantially and often did not achieve guideline parameters. The findings suggest a need to improve CPR training, consider changes to CPR protocols, and/or improve the AED-rescuer interface.     

A novel method to decrease mattress compression during CPR using a mattress compression cover and a vacuum pump

Background

Mattress compression causes feedback devices to over-estimate the chest compression depth measurement during CPR. We propose a novel method to decrease the mattress compression using a vinyl cover. This mattress compression cover encloses the foam mattress and is compressed by a vacuum pump immediately prior to performing CPR.

Methods

Nine CPR providers performed chest compressions on manikins placed on a conventional foam mattress on a bed frame (surface CONV), a backboard and foam mattress on a bed frame (surface BB), and a foam mattress, compressed with a vacuum pump, on a bed frame (surface VAC). Dual accelerometers were used to simultaneously measure the mattress compression and chest compression depths.

Results

The mattress compression depth levels decreased from 14.9 mm (SD 1.4 mm) on surface CONV to 7.0 mm (SD 0.6 mm) on surface VAC (p < 0.001) whereas 14.0 mm (SD 1.3 mm) on surface BB. The total compression depth was 65.4 mm (SD 3.8 mm) on surface CONV, and 58.3 mm (SD 3.0 mm) on surface VAC (p < 0.001).

Conclusion

Using a mattress compression cover and a vacuum pump appears to increase the rigidity of the mattress and allow for efficient chest compressions. This novel method could decrease the mattress compression depth and increase the efficiency of chest compression during CPR in hospitals.     

Comparison of Medical Priority Dispatch (MPD) and Criteria Based Dispatch (CBD) relating to cardiac arrest calls

Background

Prompt emergency medical service (EMS) system activation with rapid delivery of pre-hospital treatment is essential for patients suffering out-of-hospital cardiac arrest (OHCA). The two most commonly used dispatch tools are Medical Priority Dispatch (MPD) and Criteria Based Dispatch (CBD). We compared cardiac arrest call processing using these two dispatch tools in two different dispatch centres.

Methods

Observational study of adult EMS confirmed (non-EMS witnessed) OHCA calls during one year in Richmond, USA (MPD) and Oslo, Norway (CBD). Patients receiving CPR prior to call, interrupted calls or calls where the caller did not have access to the patients were excluded from analysis. Dispatch logs, ambulance records and digitalized dispatcher and caller voice recordings were compared.

Results

The MPDS-site processed 182 cardiac arrest calls and the CBD-site 232, of which 100 and 140 calls met the inclusion criteria, respectively. The recognition of cardiac arrest was not different in the MPD and CBD systems; 82% vs. 77% (p = 0.42), and pre-EMS arrival CPR instructions were offered to 81% vs. 74% (p = 0.22) of callers, respectively. Time to ambulance dispatch was median (95% confidence interval) 15 (13, 17) vs. 33 (29, 36) seconds (p < 0.001) and time to chest compression delivery; 4.3 (3.7, 4.9) vs. 3.7 (3.0, 4.1) min for the MPD and CBD systems, respectively (p = 0.05).

Conclusion

Pre-arrival CPR instructions were offered faster and more frequently in the CBD system, but in both systems chest compressions were delayed 3–4 min. Earlier recognition of cardiac arrest and improved CPR instructions may facilitate earlier lay rescuer CPR.