The effect of transport on quality of cardiopulmonary resuscitation in out-of-hospital cardiac arrest

IntroductionMost manikin and clinical studies have found decreased quality of CPR during transport to hospital. We wanted to study quality of CPR before and during transport for out-of-hospital cardiac arrest patients and also whether quality of CPR before initiation of transport was different from the quality in patients only receiving CPR on scene.Materials and methodsQuality of CPR was prospectively registered with a modified defibrillator for consecutive cases of out-of-hospital cardiac arrest in three ambulance services during 2002–2005. Ventilations were registered via changes in transthoracic impedance and chest compressions were measured with an extra chest compression pad placed on the patients’ sternum. Paired t-tests were used to analyse quality of CPR before vs. during transport with ongoing CPR. Unpaired t-tests were used to compare CPR quality prior to transport to CPR quality in patients with CPR terminated on site.ResultsQuality of CPR did not deteriorate during transport, but as previously reported overall quality of CPR was substandard. Quality of CPR performed on site was significantly better when transport was not initiated with ongoing CPR compared to episodes with initiation of transport during CPR: fraction of time without chest compressions was 0.45 and 0.53 (p < 0.001), compression depth 37 mm and 34 mm (p = 0.04), and number of chest compressions per minute 61 and 56 (p = 0.01), respectively.ConclusionCPR quality was sub-standard both before and during transport. Early decision to transport might have negatively affected CPR quality from the early stages of resuscitation.     

Effect of implementation of new resuscitation guidelines on quality of cardiopulmonary resuscitation and survival

BackgroundDuring cardiopulmonary resuscitation (CPR), advanced life support (ALS) providers have been shown to deliver inadequate CPR with long intervals without chest compressions. Several changes made to the 2005 CPR Guidelines were intended to reduce unnecessary interruptions. We have evaluated if quality of CPR performed by the Oslo Emergency Medical System (EMS) improved after implementation of the modified 2005 CPR Guidelines, and if any such improvement would result in increased survival.Materials and methodsRetrospective, observational study of all consecutive adult cardiac arrest patients treated during a 2-year period before (May 2003–April 2005), and after (January 2006–December 2007) implementation of the modified 2005 CPR Guidelines. CPR quality was assessed from continuous electronic recordings from LIFEPACK 12 defibrillators where ventilations and chest compressions were identified from transthoracic impedance changes. Ambulance run sheets, Utstein forms and hospital records were collected and outcome evaluated.ResultsResuscitation was attempted in 435 patients before and 481 patients after implementation of the modified 2005 CPR Guidelines. ECGs usable for CPR quality evaluation were obtained in 64% and 76% of the cases, respectively. Pre-shock pauses decreased from median (interquartile range) 17 s (11, 22) to 5 s (2, 17) (p = 0.000), overall hands-off ratios from 0.23 ± 0.13 to 0.14 ± 0.09 (p = 0.000), compression rates from 120 ± 9 to 115 ± 10 (p = 0.000) and ventilation rates from 12 ± 4 to 10 ± 4 (p = 0.000). Overall survival to hospital discharge was 11% and 13% (p = 0.287), respectively.ConclusionQuality of CPR improved after implementation of the modified 2005 Guidelines with only a weak trend towards improved survival to hospital discharge.     

Improved chest recoil using an adhesive glove device for active compression–decompression CPR in a pediatric manikin model

ObjectiveWe developed an adhesive glove device (AGD) to perform ACD-CPR in pediatric manikins, hypothesizing that AGD-ACD-CPR provides better chest decompression compared to standard (S)-CPR.DesignSplit-plot design randomizing 16 subjects to test four manikin-technique models in a crossover fashion to AGD-ACD-CPR vs. S-CPR. Healthcare providers performed 5 min of CPR with 30:2 compression:ventilation ratio in the four manikin models: (1) adolescent; (2) child two-hand; (3) child one-hand; and (4) infant two-thumb.MethodsModified manikins recorded compression pressure (CP), compression depth (CD) and decompression depth (DD). The AGD consisted of a modified oven mitt with an adjustable strap; a Velcro patch was sewn to the palmer aspect. The counter Velcro patch was bonded to the anterior chest wall. For infant CPR, the thumbs of two oven mitts were stitched together with Velcro. Subjects were asked to actively pull up during decompression. Subjects’ heart rate (HR), respiratory rate (RR) and recovery time (RT) for HR/RR to return to baseline were recorded. Subjects were blinded to data recordings. Data (mean ± SEM) were analyzed using a two-tailed paired t-test. Significance was defined qualitatively as P ≤ 0.05.ResultsMean decompression depth difference was significantly greater with AGD-ACD-CPR compared to S-CPR; 38–75% of subjects achieved chest decompression to or beyond baseline. AGD-ACD-CPR provided 6–12% fewer chest compressions/minute than S-CPR group. There was no significant difference in CD, CP, HR, RR and RT within each group comparing both techniques.ConclusionA simple, inexpensive glove device for ACD-CPR improved chest decompression with emphasis on active pull in manikins without excessive rescuer fatigue. The clinical implication of fewer compressions/minute in the AGD group needs to be evaluated.     

Effectiveness of simplified chest compression-only CPR training program with or without preparatory self-learning video: A randomized controlled trial

ObjectivesTo evaluate the effectiveness of 1-h practical chest compression-only cardiopulmonary resuscitation (CPR) training with or without a preparatory self-learning video.MethodsParticipants were randomly assigned to either a control group or a video group who received a self-learning video before attending the 1-h chest compression-only CPR training program. The primary outcome measure was the total number of chest compressions during a 2-min test period.Results214 participants were enrolled, 183 of whom completed this study. In a simulation test just before practical training began, 88 (92.6%) of the video group attempted chest compressions, while only 58 (64.4%) of the control group (p < 0.001) did so. The total number of chest compressions was significantly greater in the video group than in the control group (100.5 ± 61.5 versus 74.4 ± 55.5, p = 0.012). The proportion of those who attempted to use an automated external defibrillator (AED) was significantly greater in the video group (74.7% versus 28.7%, p < 0.001). After the 1-h practical training, the number of total chest compressions markedly increased regardless of the type of CPR training program and inter-group differences had almost disappeared (161.0 ± 31.8 in the video group and 159.0 ± 35.7 in the control group, p = 0.628).Conclusions1-h chest compression-only CPR training makes it possible for the general public to perform satisfactory chest compressions. Although a self-learning video encouraged people to perform CPR, their performance levels were not sufficient, confirming that practical training as well is essential. (UMIN000001046).     

Effect of mattress deflection on CPR quality assessment for older children and adolescents

Appropriate chest compression (CC) depth is associated with improved CPR outcome. CCs provided in hospital are often conducted on a compliant mattress. The objective was to quantify the effect of mattress compression on the assessment of CPR quality in children.MethodsA force and deflection sensor (FDS) was used during CPR in the Pediatric Intensive Care Unit and Emergency Department of a children's hospital. The sensor was interposed between the chest of the patient and hands of the rescuer and measured CC depth. Following CPR event, each event was reconstructed with a manikin and an identical mattress/backboard/patient configuration. CCs were performed using FDS on the sternum and a reference accelerometer attached to the spine of the manikin, providing a means to calculate the mattress deflection.ResultsTwelve CPR events with 14,487 CC (11 patients, median age 14.9 years) were recorded and reconstructed: 9 on ICU beds (9296 CC), 3 on stretchers (5191 CC). Measured mean CC depth during CPR was 47 ± 8 mm on ICU beds, and 45 ± 7 mm on stretcher beds with overestimation of 13 ± 4 mm and 4 ± 1 mm, respectively, due to mattress compression. After adjusting for this, the proportion of CC that met the CPR guidelines decreased from 88.4 to 31.8% on ICU beds (p < 0.001), and 86.3 to 64.7% on stretcher (p < 0.001). The proportion of appropriate depth CC was significantly smaller on ICU beds (p < 0.001).ConclusionCC conducted on a non-rigid surface may not be deep enough. FDS may overestimate CC depth by 28% on ICU beds, and 10% on stretcher beds.     

Comparison of mechanical characteristics of the human and porcine chest during cardiopulmonary resuscitation

BackgroundMost studies investigating cardiopulmonary resuscitation (CPR) interventions or functionality of mechanical CPR devices have been performed using porcine models. The purpose of this study was to identify differences between mechanical characteristics of the human and porcine chest during CPR.Material and methodsCPR data of 90 cardiac arrest patients was compared to data of 14 porcine from two animal studies. Chest stiffness k and viscosity μ were calculated from acceleration and pressure data recorded using a Laerdal Heartstart 4000SP defibrillator during CPR. K and μ were calculated at chest compression depths of 15, 30 and 50 mm for three different time periods.ResultsAt a depth of 15 mm porcine chest stiffness was comparable to human chest stiffness at the beginning of resuscitation (4.8 vs. 4.5 N/mm) and clearly lower after 200 chest compressions (2.9 vs. 4.5 N/mm) (p < 0.05). At 30 and 50 mm porcine chest stiffness was higher at the beginning and comparable to human chest stiffness after 200 chest compressions. After 200 chest compressions porcine chest viscosity was similar to human chest viscosity at 15 mm (108 vs. 110 Ns/m), higher for 30 mm (240 vs. 188 Ns/m) and clearly higher for 50 mm chest compression depth (672 vs. 339 Ns/m) (p < 0.05).ConclusionIn conclusion, human and porcine chest behave relatively similarly during CPR with respect to chest stiffness, but differences in chest viscosity at medium and deep chest compression depth should at least be kept in mind when extrapolating porcine results to humans.     

Quantitative relationship between end-tidal carbon dioxide and CPR quality during both in-hospital and out-of-hospital cardiac arrest

ObjectiveCardiopulmonary resuscitation (CPR) guidelines recommend the administration of chest compressions (CC) at a standardized rate and depth without guidance from patient physiologic output. The relationship between CC performance and actual CPR-generated blood flow is poorly understood, limiting the ability to define “optimal” CPR delivery. End-tidal carbon dioxide (ETCO₂) has been proposed as a surrogate measure of blood flow during CPR, and has been suggested as a tool to guide CPR despite a paucity of clinical data. We sought to quantify the relationship between ETCO₂ and CPR characteristics during clinical resuscitation care.MethodsMulticenter cohort study of 583 in- and out-of-hospital cardiac arrests with time-synchronized ETCO₂ and CPR performance data captured between 4/2006 and 5/2013. ETCO₂, ventilation rate, CC rate and depth were averaged over 15-s epochs. A total of 29,028 epochs were processed for analysis using mixed-effects regression techniques.ResultsCC depth was a significant predictor of increased ETCO₂. For every 10 mm increase in depth, ETCO₂ was elevated by 1.4 mmHg (p < .001). For every 10 breaths/min increase in ventilation rate, ETCO₂ was lowered by 3.0 mmHg (p < .001). CC rate was not a predictor of ETCO₂ over the dynamic range of actual CC delivery. Case-averaged ETCO₂ values in patients with return of spontaneous circulation were higher compared to those who did not have a pulse restored (34.5 ± 4.5 vs 23.1 ± 12.9 mmHg, p < .001).ConclusionsETCO₂ values generated during CPR were statistically associated with CC depth and ventilation rate. Further studies are needed to assess ETCO₂ as a potential tool to guide care.     

The effects of music on the cardiac resuscitation education of nursing students

PurposeThe purpose of this study is to examine the effects of music on the appropriate performance of the rate and depth of chest compression for nursing students.MethodsThis randomized controlled study was conducted in the School of Nursing in Turkey between November 2014 and January 2015. The study’s participants were second-year nursing school students with no previous formal cardiac resuscitation training (n = 77). Participants were randomly assigned to one of two groups: an intervention group with music and a control group without music. During practical training, the intervention group performed chest compressions with music. The outcomes of this study were collected twice. The first evaluation was conducted one day after CPR education, and the second evaluation was conducted six weeks after the initial training.ResultsThe first evaluation shows that the participants in the intervention group had an average rate of 107.33 ± 7.29 chest compressions per minute, whereas the rate for the control group was 121.47 ± 12.91. The second evaluation shows that the rates of chest compression for the intervention and control groups were 106.24 ± 8.72 and 100.71 ± 9.54, respectively.ConclusionThe results of this study show that a musical piece enables students to remember the ideal rhythm for chest compression. Performing chest compression with music can easily be integrated into CPR education because it does not require additional technology and is cheap.     

Effectiveness of simplified 15-min refresher BLS training program: A randomized controlled trial

ObjectivesTo evaluate the long-term effectiveness of 15-min refresher basic life support (BLS) training following 45-min chest compression-only BLS training.MethodsAfter the 45-min chest compression-only BLS training, the participants were randomly assigned to either the refresher BLS training group, which received a 15-min refresher training 6 months after the initial training (refresher training group), or to the control group, which did not receive refresher training. Participants’ resuscitation skills were evaluated by a 2-min case-based scenario test 1 year after the initial training. The primary outcome measure was the number of appropriate chest compressions during a 2-min test period.Results140 participants were enrolled and 112 of them completed this study. The number of appropriate chest compressions performed during the 2-min test period was significantly greater in the refresher training group (68.9 ± 72.3) than in the control group (36.3 ± 50.8, p = 0.009). Time without chest compressions was significantly shorter in the refresher training group (16.1 ± 2.1 s versus 26.9 ± 3.7 s, p < 0.001). There were no significant differences in time to chest compression (29.6 ± 16.7 s versus 34.4 ± 17.8 s, p = 0.172) and AED use between the groups.ConclusionsA short-time refresher BLS training program 6 months after the initial training can help trainees retain chest compression skills for up to 1 year. Repeated BLS training, even if very short, would be adopted to keep acquired CPR quality optimal (UMIN-CTR UMIN 000004101).     

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

Objective

The aim of this randomized cross-over study was to compare one-minute and two-minute continuous chest compressions in terms of chest compression only CPR quality metrics on a mannequin model in the ED.

An investigation of thrust,depth and the impedance cardiogram as measures of cardiopulmonary resuscitation efficacy in a porcine model of cardiac arrest

ObjectiveOptimising the depth and rate of applied chest compressions following out of hospital cardiac arrest is crucial in maintaining end organ perfusion and improving survival. The impedance cardiogram (ICG) measured via defibrillator pads produces a characteristic waveform during chest compressions with the potential to provide feedback on cardiopulmonary resuscitation (CPR) and enhance performance. The objective of this pre-clinical study was to investigate the relationship between mechanical and physiological markers of CPR efficacy in a porcine model and examine the strength of correlation between the ICG amplitude, compression depth and end-tidal CO₂ (ETCO₂).MethodsTwo experiments were performed using 24 swine (12 per experiment). For experiment 1, ventricular fibrillation (VF) was induced and mechanical CPR commenced at varying thrusts (0–60 kg) for 2 min intervals. Chest compression depth was recorded using a Philips QCPR device with additional recording of invasive physiological parameters: systolic blood pressure, ETCO2, cardiac output and carotid flow. For experiment 2, VF was induced and mechanical CPR commenced at varying depths (0–5 cm) for 2 min intervals. The ICG was recorded via defibrillator pads attached to the animal's sternum and connected to a Heartsine 500P defibrillator. ICG amplitude, chest compression depth, systolic blood pressure and ETCO₂ were recorded during each cycle. In both experiments the within-animal correlation between the measured parameters was assessed using a mixed effect model.ResultsIn experiment 1 moderate within-animal correlations were observed between physiological parameters and compression depth (r = 0.69–0.77) and thrust (r = 0.66–0.82). A moderate correlation was observed between compression depth and thrust (r = 0.75). In experiment 2 a strong within-animal correlation and moderate overall correlations were observed between ICG amplitude and compression depth (r = 0.89, r = 0.79) and ETCO₂ (r = 0.85, r = 0.64).ConclusionIn this porcine model of induced cardiac arrest moderate within animal correlations were observed between mechanical and physiological markers of chest compression efficacy demonstrating the challenge in utilising a single mechanical metric to quantify chest compression efficacy. ICG amplitude demonstrated strong within animal correlations with compression depth and ETCO₂ suggesting its potential utility to provide CPR feedback in the out of hospital setting to improve performance.     

The Specific Effect of Metronome Guidance on the Quality of One-person Cardiopulmonary Resuscitation and Rescuer Fatigue

Background

Metronome guidance is a simple and economic feedback method of guiding cardiopulmonary resuscitation (CPR). It has been proven for its usefulness in regulating the rate of chest compression and ventilation, but it is not yet clear how metronome use may affect compression depth or rescuer fatigue.

Study Objective

The aim of this study was to assess the specific effect that metronome guidance has on the quality of CPR and rescuer fatigue.

Methods

One-person CPRs were performed by senior medical students on Resusci Anne® manikins (Laerdal, Stavanger, Norway) with personal-computer skill-reporting systems. Half of the students performed CPR with metronome guidance and the other half without. CPR performance data, duration, and before–after trial differences in mean arterial pressure (MAP) and heart rate (HR) were compared between groups.

Results

Average compression depth (ACD) of the first five cycles, compression rate, no-flow fraction, and ventilation count were significantly lower in the metronome group (p = 0.028, < 0.001, 0.001, and 0.041, respectively). Total CPR duration, total work (ACD × total compression count), and the before–after trial differences of the MAP and HR did not differ between the two groups.

Conclusions

Metronome guidance is associated with lower chest compression depth of the first five cycles, while shortening the no-flow fraction and the ventilation count in a simulated one-person CPR model. Metronome guidance does not have an obvious effect of intensifying rescuer fatigue.     

The impact of quantitative feedback on the performance of chest compression by basic life support trained clinical staff

BackgroundThe quality of CPR is directly related to survival outcomes following sudden cardiac arrest but, CPR competency amongst nursing and medical staff is generally poor. The skills honed in CPR recertification training rapidly decline in quality, even as soon as eight weeks following the training. High frequency low dose training has been recommended to address this decay in skills. Automated training devices that provide feedback may be useful in conducting low dose training, which would assist hospitals to manage the often logistically difficult, and financially costly exercise of conducting training programs. Little evidence is published about the improvement in skills performance that can be derived from isolated feedback from these training devices.ObjectivesTo investigate whether the feedback from an automated training device can produce performance in a ‘low dose’ episode of re-training on chest compressions and compression depth for CPR.MethodsA repeated measures study was conducted assessing the compression rate and depth quality over 2 min using a Laerdal QCPR® simulation manikin capable of recording performance data. On-screen feedback was provided to participants between attempts. Convenience sampling recruited undergraduate and qualified nursing and medical staff who were engaged in a CPR recertification program at a major Australian private hospital.ResultsIn total, 150 participants were enrolled. Feedback from the automated training device was sufficient to produce a significant improvement in both chest compression rate (95% CI 13.3 to 19.7; p < 0.001) and depth (95% CI 5.9 to 9.7; p < 0.001) during the low dose training episode.ConclusionsThe feedback provided from an automated training device was sufficient to produce an improvement in performance in chest compressions in CPR. This demonstrates an alternate staff training model that could improve patient outcomes, and allow for higher frequency training whilst potentially reducing costs and the logistical problems many medical institutions face with staff training.     

Quality of cardio-pulmonary resuscitation (CPR) during paediatric resuscitation training: Time to stop the blind leading the blind

AimsRecent evidence suggested that the quality of cardio-pulmonary resuscitation (CPR) during adult advanced life support training was suboptimal. This study aimed to assess the CPR quality of a paediatric resuscitation training programme, and to determine whether it was sufficiently addressed by the trainee team leaders during training.MethodsCPR quality of 20 consecutive resuscitation scenario training sessions was audited prospectively using a pre-designed proforma. A consultant intensivist and a senior nurse who were also Advanced Paediatric Life Support (APLS) instructors assessed the CPR quality which included ventilation frequency, chest compression rate and depth, and any unnecessary interruption in chest compressions. Team leaders’ response to CPR quality and elective change of compression rescuer during training were also recorded.ResultsAirway patency was not assessed in 13 sessions while ventilation rate was too fast in 18 sessions. Target compression rate was not achieved in only 1 session. The median chest compression rate was 115 beats/min. Chest compressions were too shallow in 10 sessions and were interrupted unnecessarily in 13 sessions. More than 50% of training sessions did not have elective change of the compression rescuer. 19 team leaders failed to address CPR quality during training despite all team leaders being certified APLS providers.ConclusionsThe quality of CPR performance was suboptimal during paediatric resuscitation training and team leaders-in-training had little awareness of this inadequacy. Detailed CPR quality assessment and feedback should be integrated into paediatric resuscitation training to ensure optimal performance in real life resuscitations.     

The impact of compliant surfaces on in-hospital chest compressions: Effects of common mattresses and a backboard

PurposeTo evaluate, in a hospital setting, the influence of different, common mattresses, with and without a backboard, on chest movement during CPR.Design and settingSixty CPR sessions (140 s each, 30:2, C:R ratio 1:1) were performed using a manikin on standard hospital mattresses, with or without a backboard in combination with variable weights. Sternum-to-spine compression distance was controlled (range 30–60 mm) allowing evaluation of the underlying compliant surface on total hand travel.ResultsMovement of the caregiver's hands was significantly larger (up to 111 mm at 50 mm compression depth, p < 0.0001) when sternum-to-spine compressions were performed without a backboard than with one. The extent of this variable extra travel effect depended on the type of mattress as well as the force of compression. Foam mattresses and air chamber systems act as springs and follow hand movement, while ‘slow foam’ mattresses incorporate time delays, making depth and force sensing harder. A backboard decreases the extra hand movement due to mattress effects by more than 50%, strongly reducing caregiver work.ConclusionsTotal vertical hand movement is significantly, and clinically relevantly, much larger than sternum-to-spine compression depth when CPR is performed on a mattress. Additional movement depends on the type of mattress and can be strongly reduced, but not eliminated, when a backboard is applied. The additional motion and increased work load adds extra complexity to in-hospital CPR. We propose that this should be taken into account during training by in-hospital caregivers.     

Effect of continuous oxygen insufflation on induced-gastric air volume during cardiopulmonary resuscitation in a cadaveric model

BackgroundThe main objective of this study was to compare the volume of gas insufflated in the stomach with continuous external chest compressions plus continuous oxygen insufflation (C-CPR) versus standard-CPR (S-CPR) which alternates external chest compressions and synchronized positive insufflations through a bag-valve-mask with a 30/2 ratio. The secondary objective was to compare upper airway pressures (intratracheal and intramask) generated during continuous oxygen insufflation.Material and methodsOpen, prospective, randomized, cross over, comparative, non-inferiority study. CPR was performed for six minutes periods, on seven fresh human corpses, with C-CPR or S-CPR in a random order. Before each CPR period, the stomach was completely emptied through the gastrostomy tube, and then 200 mL of air was injected in the stomach to be sure it was not collapsed. The gastric volume was measured at the end of each intervention. Intratracheal and intramask pressures were recorded continuously during C-CPR. Results were provided as mean ± standard deviation. Statistical analyses were done with a paired student t test.ResultsInduced-gastric inflation was lower with C-CPR (221 ± 130 mL) than with S-CPR (5401 ± 2208 mL, p = 0.001). Throughout C-CPR, no difference was found between the intratracheal and intramask pressures (4.4 ± 1.2; 4.0 ± 0.8 cmH₂O, respectively, p = 0.45).ConclusionThis human cadaver study demonstrates that continuous oxygen insufflation induced less gastric inflation than intermittent insufflation during CPR.     

Oxygen requirement during cardiopulmonary resuscitation (CPR) to effect return of spontaneous circulation

BackgroundRecent scientific evidence has demonstrated the importance of good quality chest compressions without interruption to improve cardiac arrest resuscitation rates, and suggested that a de-emphasis on minute ventilation is needed. However, independent of ventilation, the role of oxygen and the optimal oxygen concentration during CPR is not known. Previous studies have shown that ventilation with high oxygen concentration after CPR is associated with worse neurologic outcome. We tested the hypothesis that initial ventilation during CPR without oxygen improves resuscitation success.MethodsSprague–Dawley rats were anesthetized with ketamine/xylazine (IP), intubated and ventilated with room air. A KCl bolus (0.04 mg/g) was given (IV) to induce asystolic cardiac arrest and ventilation was stopped. At 6 min, CPR was started with an automated chest compressor at a rate of 200–240/min and epinephrine (0.01 mg/kg) was given 1 min later. During CPR, the ventilation rate was 50% of baseline with one of three oxygen concentrations: (1) 0% O₂ (100% N₂), (2) 21% O₂, or (3) 100% O₂. The prescribed oxygen concentration was continued for 2 min after return of spontaneous circulation (ROSC) and then all animals were switched to 100% oxygen for 1 h prior to extubation. Blood gases were measured at baseline, 2 min and 1 h after ROSC. Group comparisons were done using Fisher's exact test and ANOVA.ResultsROSC was achieved in 1/10 (0% O₂), 9/11 (21% O₂) and 10/12 (100% O₂, p < 0.001). ROSC times after starting CPR were 80 s in the 0% O₂, 115 ± 87 s in the 21% O₂ group and 95 ± 33 s in the 100% O₂ group (mean ± SD, p = 0.5). Aortic end-diastolic pressure before ROSC was not different among groups. 100% oxygen ventilation in the first 2 min resulted in higher PaO₂ at ROSC 2 min (109 ± 44 mm Hg vs. 33 ± 8 mm Hg, p < 0.001). Survival to 72 h was 0/1 (0% O₂), 7/9 (21% O₂) and 8/10 (100% O₂) with a low neurologic deficit score in both O₂ groups (NDS range 5–25).ConclusionsIn a mild cardiac arrest model with generally good neurologic recovery, initial CPR ventilation with no O₂ did not allow for ROSC. In contrast, CPR coupled with room air or higher oxygen levels result in a high rate of ROSC with good neurologic recovery. During CPR, the level of oxygenation must be considered, which if too low may preclude initial ROSC.     

The capability of professional- and lay-rescuers to estimate the chest compression-depth target: A short,randomized experiment

BackgroundIn CPR, sufficient compression depth is essential. The American Heart Association (“at least 5 cm”, AHA-R) and the European Resuscitation Council (“at least 5 cm, but not to exceed 6 cm”, ERC-R) recommendations differ, and both are hardly achieved. This study aims to investigate the effects of differing target depth instructions on compression depth performances of professional and lay-rescuers.Methods110 professional-rescuers and 110 lay-rescuers were randomized (1:1, 4 groups) to estimate the AHA-R or ERC-R on a paper sheet (given horizontal axis) using a pencil and to perform chest compressions according to AHA-R or ERC-R on a manikin. Distance estimation and compression depth were the outcome variables.ResultsProfessional-rescuers estimated the distance according to AHA-R in 19/55 (34.5%) and to ERC-R in 20/55 (36.4%) cases (p = 0.84). Professional-rescuers achieved correct compression depth according to AHA-R in 39/55 (70.9%) and to ERC-R in 36/55 (65.4%) cases (p = 0.97).Lay-rescuers estimated the distance correctly according to AHA-R in 18/55 (32.7%) and to ERC-R in 20/55 (36.4%) cases (p = 0.59). Lay-rescuers yielded correct compression depth according to AHA-R in 39/55 (70.9%) and to ERC-R in 26/55 (47.3%) cases (p = 0.02).ConclusionProfessional and lay-rescuers have severe difficulties in correctly estimating distance on a sheet of paper. Professional-rescuers are able to yield AHA-R and ERC-R targets likewise. In lay-rescuers AHA-R was associated with significantly higher success rates. The inability to estimate distance could explain the failure to appropriately perform chest compressions. For teaching lay-rescuers, the AHA-R with no upper limit of compression depth might be preferable.     

Cardiopulmonary resuscitation quality and patient survival outcome in cardiac arrest: A systematic review and meta-analysis

AimTo conduct a systematic review and meta-analysis to determine whether cardiopulmonary resuscitation (CPR) quality, as indicated by parameters such as chest compression depth, compression rate and compression fraction, is associated with patient survival from cardiac arrest.MethodsFive databases were searched (MEDLINE, Embase, CINAHL, Scopus and Cochrane) as well as the grey literature (MedNar). To satisfy inclusion criteria, studies had to document human cases of in- or out-of hospital cardiac arrest where CPR quality had been recorded using an automated device and linked to patient survival. Where indicated (I² < 75%), meta-analysis was undertaken to examine the relationship between individual CPR quality parameters and either survival to hospital discharge (STHD) or return of spontaneous circulation (ROSC).ResultsDatabase searching yielded 8,842 unique citations, resulting in the inclusion of 22 relevant articles. Thirteen were included in the meta-analysis. Chest compression depth was significantly associated with STHD (mean difference (MD) between survivors and non-survivors 2.59 mm, 95% CI: 0.71, 4.47); and with ROSC (MD 0.99 mm, 95% CI: 0.04, 1.93). Within the range of approximately 100–120 compressions per minute (cpm), compression rate was significantly associated with STHD; survivors demonstrated a lower mean compression rate than non-survivors (MD −1.17 cpm, 95% CI: −2.21, −0.14). Compression fraction could not be examined by meta-analysis due to high heterogeneity, however a higher fraction appeared to be associated with survival in cases with a shockable initial rhythm.ConclusionsChest compression depth and rate were associated with survival outcomes. More studies with consistent reporting of data are required for other quality parameters.     

Resuscitator's perceptions and time for corrective ventilation steps during neonatal resuscitation

BackgroundThe 2010 neonatal resuscitation program (NRP) guidelines incorporate ventilation corrective steps (using the mnemonic – MRSOPA) into the resuscitation algorithm. The perception of neonatal providers, time taken to perform these maneuvers or the effectiveness of these additional steps has not been evaluated.MethodsUsing two simulated clinical scenarios of varying degrees of cardiovascular compromise – perinatal asphyxia with (i) bradycardia (heart rate – 40 min^–1) and (ii) cardiac arrest, 35 NRP certified providers were evaluated for preference to performing these corrective measures, the time taken for performing these steps and time to onset of chest compressions.ResultsThe average time taken to perform ventilation corrective steps (MRSOPA) was 48.9 ± 21.4 s. Providers were less likely to perform corrective steps and proceed directly to endotracheal intubation in the scenario of cardiac arrest as compared to a state of bradycardia. Cardiac compressions were initiated significantly sooner in the scenario of cardiac arrest 89 ± 24 s as compared to severe bradycardia 122 ± 23 s, p < 0.0001. There were no differences in the time taken to initiation of chest compressions between physicians or mid-level care providers or with the level of experience of the provider.ConclusionsEffective ventilation of the lungs with corrective steps using a mask is important in most cases of neonatal resuscitation. Neonatal resuscitators prefer early endotracheal intubation and initiation of chest compressions in the presence of asystolic cardiac arrest. Corrective ventilation steps can potentially postpone initiation of chest compressions and may delay return of spontaneous circulation in the presence of severe cardiovascular compromise.