Chest compressions performed by ED staff: a randomized cross-over simulation study on the floor and on a stretcher

Background

Multiple factors may contribute to the observed survival variability following in-hospital cardiopulmonary resuscitation (CPR). While in-hospital CPR is most often performed on patients lying on a bed or stretcher, CPR training uses primarily manikins placed on the floor. We analyzed the quality of external chest compressions (ECC) in simulated cardiac arrest scenarios occurring both on a stretcher and on the floor.

Methods

Prospective cross-over simulation study enrolling ED nurses and nurse's aides as part of an annual evaluation. Simulated CPR was performed in the 2 rescuer-mode for 2 min, both kneeling on the floor, and standing beside a knee high stretcher. The order of position was randomized. ECC parameters were compared.

Results

ED nurses (n = 48) and nurse's aides (n = 26) performed 128 scenarios. Mean ECC depth was 32 ± 13 mm on the floor and 27 ± 11 mm on a stretcher (?: 5 mm, 95%CI [3-7], P < .001). Participants last trained within a year (n = 17) developed deeper ECCs than their colleagues (n = 47) in both positions (floor: 39 ± 12 mm vs stretcher: 34 ± 11 mm (p = 0.016) for those trained within the year, and floor: 29 ± 12 mm vs stretcher: 24 ± 10 mm (P < .001) for those trained over a year ago).

Conclusions

The quality of chest compressions performed by ED staff was below 2005 guideline standards, with decreased ECC depth during CPR on a stretcher. Annual refresher courses should be implemented in the ED, with a focus on obtaining required ECC depth while standing next to a stretcher.     

A Simple Audio-visual Prompt Device Can Improve CPR Performance

Background

An adjunct to assist cardiopulmonary resuscitation (CPR) might improve the quality of CPR performance.

Study Objectives

This study was conducted to evaluate whether a simple audio-visual prompt device improves CPR performance by emergency medical technicians (EMTs).

Methods

From June 2008 to October 2008, 55 EMTs (39 men, mean age 34.9 ± 4.8 years) participated in this study. A simple audio-visual prompt device was developed. The device generates continuous metronomic sounds for chest compression at a rate of 100 beats/min with a distinct 30^th sound followed by two respiration sounds, each for 1 second. All EMTs were asked to perform a 2-min CPR series on a manikin without the device, and one 2-min CPR series with the device.

Results

The average rate of chest compressions was more accurate when the device was used than when the device was not used (101.4 ± 12.7 vs. 109.0 ± 17.4/min, respectively, p = 0.012; 95% confidence interval [CI] 97.2–103.8 vs. 104.5–113.5/min, respectively), and hands-off time during CPR was shorter when the device was used than when the device was not used (5.4 ± 0.9 vs. 9.2 ± 3.9 s, respectively, p < 0.001; 95% CI 5.2–5.7 vs. 8.3–10.3 s, respectively). The mean tidal volume during CPR with the device was lower than without the device, resulting in the prevention of hyperventilation (477.6 ± 60.0 vs. 636.6 ± 153.4 mL, respectively, p < 0.001; 95% CI 463.5–496.2 vs. 607.3–688.9 mL, respectively).

Conclusion

A simple audio-visual prompt device can improve CPR performance by emergency medical technicians.     

Accurate feedback of chest compression depth on a manikin on a soft surface with correction for total body displacement

Objective

TrueCPR is a new real-time compression depth feedback device that measures changes in magnetic field strength between a back pad and a chest pad. We determined its accuracy with a manikin on a test bench and on various surfaces.

Methods

First, calibration and accuracy of the manikin and TrueCPR was verified on a drill press. Then, manual chest compressions were given, on a firm surface and on a foam or air mattress, with feedback of the TrueCPR or Q-CPR accelerometer, to achieve a depth of 50 mm. Compression depth measurements by the devices and the manikin were compared.

Results

On a hard surface TrueCPR showed a systematic underestimation of 2–3 mm in the drill press. Manual tests on a hard surface showed a slightly larger underestimation of 4.5 mm. When guided by TrueCPR on a foam or air mattress, the TrueCPR measured a mean(±SD) chest compression depth of 52.0(±1.9) mm and 49.4(±2.6) mm respectively, while the manikin measured 54.4(±1.8) mm and 52.1(±1.4) mm, respectively (p < 0.001). When guided by the Q-CPR accelerometer on a foam or air mattress, the accelerometer measured depth of 54.3(±3.6) mm and 56.0(±3.8) mm respectively, compared to the manikin 42.4(±2.3) mm and 34.9(±3.6) mm, respectively (p < 0.001).

Conclusion

TrueCPR measures depth precisely, independent of the stiffness of the surface upon which the CPR is being performed with a constant inaccuracy of <4.5 mm. A sternum-only accelerometer substantially overestimates depth when performing CPR on a soft surface. Correction for body displacement on a soft surface is essential for accurate delivery of chest compressions within the recommended depth range.     

Effects of repetitive or intensified instructions in telephone assisted,bystander cardiopulmonary resuscitation: An investigator-blinded, 4-armed,randomized, factorial simulation trial

Background

Compression depth is frequently suboptimal in cardiopulmonary resuscitation (CPR). We investigated effects of intensified wording and/or repetitive target depth instructions on compression depth in telephone-assisted, protocol driven, bystander CPR on a simulation manikin.

Methods

Thirty-two volunteers performed 10 min of compression only-CPR in a prospective, investigator-blinded, 4-armed, factorial setting. Participants were randomized either to standard wording (“push down firmly 5 cm”), intensified wording (“it is very important to push down 5 cm every time”) or standard or intensified wording repeated every 20 s. Three dispatchers were randomized to give these instructions. Primary outcome was relative compression depth (absolute compression depth minus leaning depth). Secondary outcomes were absolute distance, hands-off times as well as BORG-scale and nine-hole peg test (NHPT), pulse rate and blood pressure to reflect physical exertion. We applied a random effects linear regression model.

Results

Relative compression depth was 35 ± 10 mm (standard) versus 31 ± 11 mm (intensified wording) versus 25 ± 8 mm (repeated standard) and 31 ± 14 mm (repeated intensified wording).Adjusted for design, body mass index and female sex, intensified wording and repetition led to decreased compression depth of 13 (95%CI −25to −1) mm (p = 0.04) and 9 (95%CI −21 to 3) mm (p = 0.13), respectively. Secondary outcomes regarding intensified wording showed significant differences for absolute distance (43 ± 2 versus 20 (95%CI 3–37) mm; p = 0.01) and hands-off times (60 ± 40 versus 157 (95%CI 63–251) s; p = 0.04).

Conclusion

In protocol driven, telephone-assisted, bystander CPR, intensified wording and/or repetitive target depth instruction will not improve compression depth compared to the standard instruction.     

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.     

Intrathoracic pressure regulation during cardiopulmonary resuscitation: A feasibility case-series

Aim of the study

Intrathoracic pressure regulation (IPR) is a novel, noninvasive therapy intended to increase cardiac output and blood pressure in hypotensive states by generating a negative end expiratory pressure of −12 cm H₂O between positive pressure ventilations. In this first feasibility case-series, we tested the hypothesis that IPR improves End tidal (ET) CO₂ during cardiopulmonary resuscitation (CPR). ETCO₂ was used as a surrogate measure for circulation.

Methods

All patients were treated initially with manual CPR and an impedance threshold device (ITD). When IPR-trained medics arrived on scene the ITD was removed and an IPR device (CirQLATOR™) was attached to the patient's advanced airway (intervention group). The IPR device lowered airway pressures to −9 mmHg after each positive pressure ventilation for the duration of the expiratory phase. ETCO₂, was measured using a capnometer incorporated into the defibrillator system (LifePak™). Values are expressed as mean ± SEM. Results were compared using paired and unpaired Student's t test. p values of <0.05 were considered statistically significant.

Results

ETCO₂ values in 11 patients in the case series were compared pre and during IPR therapy and also compared to 74 patients in the control group not treated with the new IPR device. ETCO₂ values increased from an average of 21 ± 1 mmHg immediately before IPR application to an average value of 32 ± 5 mmHg and to a maximum value of 45 ± 5 mmHg during IPR treatment (p < 0.001). In the control group ETCO₂ values did not change significantly. Return of spontaneous circulation (ROSC) rates were 46% (34/74) with standard CPR and ITD versus 73% (8/11) with standard CPR and the IPR device (p < 0.001).

Conclusions

ETCO₂ levels and ROSC rates were significantly higher in the study intervention group. These findings demonstrate that during CPR circulation may be significantly augmented by generation of a negative end expiratory pressure between each breath.     

Pushing harder,pushing faster,minimizing interruptions… But falling short of 2010 cardiopulmonary resuscitation targets during in-hospital pediatric and adolescent resuscitation

Aim

The objective of this study was to evaluate the effect of instituting the 2010 Basic Life Support Guidelines on in-hospital pediatric and adolescent cardiopulmonary resuscitation (CPR) quality. We hypothesized that quality would improve, but that targets for chest compression (CC) depth would be difficult to achieve.

Methods

Prospective in-hospital observational study comparing CPR quality 24 months before and after release of the 2010 Guidelines. CPR recording/feedback-enabled defibrillators collected CPR data (rate (CC/min), depth (mm), CC fraction (CCF, %), leaning (% > 2.5 kg)). Audiovisual feedback for depth was: 2005, ≥38 mm; 2010, ≥50 mm; for rate: 2005, ≥90 and ≤120 CC/min; 2010, ≥100 and ≤120 CC/min. The primary outcome was average event depth compared with Student's t-test.

Results

45 CPR events (25 before; 20 after) occurred, resulting in 1336 thirty-second epochs (909 before; 427 after). Compared to 2005, average event depth (50 ± 13 mm vs. 43 ± 9 mm; p = 0.047), rate (113 ± 11 CC/min vs. 104 ± 8 CC/min; p < 0.01), and CCF (0.94 [0.93, 0.96] vs. 0.9 [0.85, 0.94]; p = 0.013) increased during 2010. CPR epochs during the 2010 period more likely to meet Guidelines for CCF (OR 1.7; CI95: 1.2–2.4; p < 0.01), but less likely for rate (OR 0.23; CI95: 0.12–0.44; p < 0.01), and depth (OR 0.31; CI95: 0.12–0.86; p = 0.024).

Conclusions

Institution of the 2010 Guidelines was associated with increased CC depth, rate, and CC fraction; yet, achieving 2010 targets for rate and depth was difficult.     

Obstacles delaying the prompt deployment of piston-type mechanical cardiopulmonary resuscitation devices during emergency department resuscitation: A video-recording and time-motion study

Background

The quality of cardiopulmonary resuscitation (CPR) is important to survival after cardiac arrest. Mechanical devices (MD) provide constant CPR, but their effectiveness may be affected by deployment timeliness.

Objectives

To identify the timeliness of the overall and of each essential step in the deployment of a piston-type MD during emergency department (ED) resuscitation, and to identify factors associated with delayed MD deployment by video recordings.

Methods

Between December 2005 and December 2008, video clips from resuscitations with CPR sessions using a MD in the ED were reviewed using time-motion analyses. The overall deployment timeliness and the time spent on each essential step of deployment were measured.

Results

There were 37 CPR recordings that used a MD. Deployment of MD took an average 122.6 ± 57.8 s. The 3 most time-consuming steps were: (1) setting the device (57.8 ± 38.3 s), (2) positioning the patient (33.4 ± 38.0 s), and (3) positioning the device (14.7 ± 9.5 s). Total no flow time was 89.1 ± 41.2 s (72.7% of total time) and associated with the 3 most time-consuming steps. There was no difference in the total timeliness, no-flow time, and no-flow ratio between different rescuer numbers, time of day of the resuscitation, or body size of patients.

Conclusions

Rescuers spent a significant amount of time on MD deployment, leading to long no-flow times. Lack of familiarity with the device and positioning strategy were associated with poor performance. Additional training in device deployment strategies are required to improve the benefits of mechanical CPR.     

A stabilization device to improve the quality of cardiopulmonary resuscitation during ambulance transportation: A randomized crossover trial

Background

The quality of cardiopulmonary resuscitation (CPR) during ambulance transportation is suboptimal, and therefore measures that can improve the quality are desirable.

Purpose

To evaluate whether the use of a stabilization device can improve the quality of CPR during ambulance transportation.

Methods

This randomized controlled crossover trial enrolled 22 experienced ambulance officers. Each participant performed CPR in an ambulance under three conditions with 72 h apart, each condition for 10 min: non-moving (NM), moving without device (MND), and moving with device (MD). The sequences of conditions were randomized. The primary outcomes were effective chest compressions recorded by the Laerdal Resusci-Anne Skill-reporter manikin. The secondary outcomes included the severity of back pain scored using the Brief Pain Inventory short-form, the physiology parameter before and after CPR, and the changes in postural stability which was represented by the sway index (SI) of lower back measured using a goniometer.

Results

The overall effective compressions in 10 min were 87.0 ± 17% for NM, 59.0 ± 19% for MND, and 69.0 ± 23% for MD (p < 0.001). Compared to MND, MD had a lower no-flow fraction while driving on curved sections (0.04 vs. 0.29, p < 0.001). Whereas the pain severity and social interference scores were similar under all conditions, MND had a higher SI than MD and NM.

Conclusions

The use of a stabilization device can improve the quality of CPR and posture stability during ambulance transportation, although the effects on the severity of back pain were not significant.     

Effect of cardiopulmonary resuscitation on restoration of myocardial ATP in prolonged ventricular fibrillation

Background

There has been controversy over whether a short period of cardiopulmonary resuscitation (CPR) prior to defibrillation improves survival in patients who experienced a sudden cardiac arrest. However, there have been no reports about whether CPR restores the myocardial energy source during prolonged ventricular fibrillation (VF). The aim of this study is to investigate the effect of CPR in restoring myocardial high energy phosphates during prolonged VF.

Methods and results

Seventy-two adult male Sprague-Dawley rats were used in this study. Baseline adenosine triphosphate (ATP) and adenosine diphosphate (ADP) prior to induction of VF were measured in nine rats, the No-VF group. Sixty-three rats were subjected to 4 min of untreated VF. Animals were then randomized into two groups: No-CPR (n = 37) and CPR (n = 26). In the No-CPR group, ATPs and ADPs were measured at 4 min (No-CPR4), 6 min (No-CPR6), 8 min (No-CPR8) or 10 min (No-CPR10) after the induction of VF. The CPR group received 2 min (CPR2), 4 min (CPR4) or 6 min (CPR6) of mechanical chest compressions before ATP was measured.Myocardial ATP (nmol/mg protein) was decreased as VF duration was prolonged (No-VF: 5.49 ± 1.71, No-CPR4: 4.27 ± 1.58, No-CPR6: 4.13 ± 1.31, No-CPR8: 3.77 ± 1.42, No-CPR10: 3.52 ± 0.90, p < 0.05 between each of No-CPRs vs. No-VF). Two minutes of CPR restored myocardial ATP to the level of No-VF group (5.27 ± 1.67 nmol/mg protein in CPR2, p > 0.05 vs. No-VF group). However, myocardial ATP (nmol/mg protein) decreased if the duration of CPR was longer than 2 min (CPR4: 3.77 ± 1.05, CPR6: 3.49 ± 1.08, p < 0.05 between CPR4 and CPR6 vs. No-VF).

Conclusions

CPR for 2 min helps to maintain myocardial ATP after prolonged VF.     

Can a flowchart improve the quality of bystander cardiopulmonary resuscitation?

Background

Since the introduction of basic life support in the 1950s, on-going efforts have been made to improve the quality of bystander cardiopulmonary resuscitation (CPR). Even though bystander-CPR can increase the chance of survival almost fourfold, the rates of bystander initiated CPR have remained low and rarely exceed 20%. Lack of confidence and fear of committing mistakes are reasons why helpers refrain from initiating CPR. The authors tested the hypothesis that quality and confidence of bystander-CPR can be increased by supplying lay helpers with a basic life support flowchart when commencing CPR, in a simulated resuscitation model.

Materials and methods

After giving written informed consent, 83 medically untrained laypersons were randomised to perform basic life support for 300s with or without a supportive flowchart. The primary outcome parameter was hands-off time (HOT). Furthermore, the participants’ confidence in their actions on a 10-point Likert-like scale and time-to-chest compressions were assessed.

Results

Overall HOT was 147 ± 30 s (flowchart) vs. 169 ± 55 s (non-flowchart), p = 0.024. Time to chest compressions was significantly longer in the flowchart group (60 ± 24 s vs. 23 ± 18 s, p < 0.0001). Participants in the flowchart group were significantly more confident when performing BLS than the non-flowchart counterparts (7 ± 2 vs. 5 ± 2, p = 0.0009).

Conclusions

A chart provided at the beginning of resuscitation attempts improves quality of CPR significantly by decreasing HOT and increasing the participants’ confidence when performing CPR. As reducing HOT is associated with improved outcome and positively impacting the helpers’ confidence is one of the main obstacles to initiate CPR for lay helpers, charts could be utilised as simple measure to improve outcome in cardiopulmonary arrest.     

Training hospital providers in basic CPR skills in Botswana: Acquisition,retention and impact of novel training techniques

Objective

Globally, one third of deaths each year are from cardiovascular diseases, yet no strong evidence supports any specific method of CPR instruction in a resource-limited setting. We hypothesized that both existing and novel CPR training programs significantly impact skills of hospital-based healthcare providers (HCP) in Botswana.

Methods

HCP were prospectively randomized to 3 training groups: instructor led, limited instructor with manikin feedback, or self-directed learning. Data was collected prior to training, immediately after and at 3 and 6 months. Excellent CPR was prospectively defined as having at least 4 of 5 characteristics: depth, rate, release, no flow fraction, and no excessive ventilation. GEE was performed to account for within subject correlation.

Results

Of 214 HCP trained, 40% resuscitate ≥1/month, 28% had previous formal CPR training, and 65% required additional skills remediation to pass using AHA criteria. Excellent CPR skill acquisition was significant (infant: 32% vs. 71%, p < 0.01; adult 28% vs. 48%, p < 0.01). Infant CPR skill retention was significant at 3 (39% vs. 70%, p < 0.01) and 6 months (38% vs. 67%, p < 0.01), and adult CPR skills were retained to 3 months (34% vs. 51%, p = 0.02). On multivariable analysis, low cognitive score and need for skill remediation, but not instruction method, impacted CPR skill performance.

Conclusions

HCP in resource-limited settings resuscitate frequently, with little CPR training. Using existing training, HCP acquire and retain skills, yet often require remediation. Novel techniques with increased student: instructor ratio and feedback manikins were not different compared to traditional instruction.     

Forensic analysis of crib mattress properties on pediatric CPR quality—Can we balance pressure reduction with CPR effectiveness?

Introduction

Single mode, pressure reduction (PR) crib mattresses are increasingly employed in hospitals to prevent skin injury and infection. However, single mode PR mattresses risk large mattress deflection during CPR chest compressions, potentially leading to inadequate chest compressions.

Hypothesis

New, dual mode PR crib mattress technology provides less mattress deflection during chest compressions (CCs) with similar PR characteristics for prevention of skin injury.

Methods

Epochs of 50 high-quality CCs (target sternum–spine compression depth ≥38 mm) guided by real-time force/deflection sensor (FDS) feedback were delivered to CPR manikin with realistic CC characteristics on two PR crib mattresses for four conditions: (1) single mode + backboard; (2) dual mode + backboard; (3) single mode − no backboard; and (4) dual mode − no backboard. Mattress displacement was measured using surface reference accelerometers. Mattress displacement ≥5 mm was prospectively defined as minimal clinically important difference. PR qualities of both mattresses were assessed by tissue interface pressure mapping.

Results

During simulated high quality CC, single mode had significantly more mattress displacement compared to dual mode (mean difference 16.5 ± 1.4 mm, p < 0.0001) with backboard. This difference was greater when no backboard was used (mean difference 31.7 ± 1.5 mm, p < 0.0001). Both single mode and dual mode met PR industry guidelines (mean surface pressure <50 mmHg).

Conclusions

Chest compressions delivered on dual mode pressure reduction crib mattresses resulted in substantially smaller mattress deflection compared to single mode pressure reduction mattresses. Skin pressure reduction qualities of dual mode pressure reduction crib mattress were maintained. We recommend that backboards continue to be used in order to mitigate mattress deflection during CPR on soft mattresses.     

Influence of nationwide policy on citizens’ awareness and willingness to perform bystander cardiopulmonary resuscitation

Aims

Public awareness to cardiopulmonary resuscitation (CPR) and cardiac arrest is influenced by systemic factors including related policies and legislations in the community. Here, we describe and compare the results of the two nationwide CPR surveys in 2007 and 2011 examining public awareness and attitudes to bystander CPR in South Korea along with changes in nationwide CPR policies and systemic factors.

Methods

This population-based study used specially designed questionnaires via telephone surveys. We conducted bi-temporal surveys by stratified cluster sampling to assess the impact of age, gender, and geographic regions in 2007 (n = 1029) and in 2011 (n = 1000). Logistic regression analysis was performed to identify factors associated with willingness to perform bystander CPR.

Results

Public awareness of automated external defibrillators increased from 3.0% in 2007 to 32.6% in 2011. The proportion of the population that underwent CPR training within the previous 2 years increased significantly from 26.9% to 49.0%. The factors most related with intention of bystander CPR were male gender, younger age, CPR awareness, recent CPR training, and qualified CPR learning. In 2011, 75.8% of respondents were more willing to perform bystander CPR for stranger vs. 68.3% in 2007 (p = 0.002). Additional dispatcher hands-only CPR increased this proportion (85.8%, p < 0.001). However, bystander CPR experience rates remained unchanged (3.6–3.9%).

Conclusion

Changes in nationwide CPR policies and systemic factors affected citizens’ awareness and willingness to perform bystander CPR. Additionally, applied dispatcher hands-only CPR and publicity increased public willingness to perform bystander CPR.     

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.     

Early coronary revascularization improves 24 h survival and neurological function after ischemic cardiac arrest. A randomized animal study

Background

Survival after out-of-hospital cardiac arrest (OHCA) remains poor. Acute coronary obstruction is a major cause of OHCA. We hypothesize that early coronary reperfusion will improve 24 h-survival and neurological outcomes.

Methods

Total occlusion of the mid LAD was induced by balloon inflation in 27 pigs. After 5 min, VF was induced and left untreated for 8 min. If return of spontaneous circulation (ROSC) was achieved within 15 min (21/27 animals) of cardiopulmonary resuscitation (CPR), animals were randomized to a total of either 45 min (group A) or 4 h (group B) of LAD occlusion. Animals without ROSC after 15 min of CPR were classified as refractory VF (group C). In those pigs, CPR was continued up to 45 min of total LAD occlusion at which point reperfusion was achieved. CPR was continued until ROSC or another 10 min of CPR had been performed. Primary endpoints for groups A and B were 24-h survival and cerebral performance category (CPC). Primary endpoint for group C was ROSC before or after reperfusion.

Results

Early compared to late reperfusion improved survival (10/11 versus 4/10, p = 0.02), mean CPC (1.4 ± 0.7 versus 2.5 ± 0.6, p = 0.017), LVEF (43 ± 13 versus 32 ± 9%, p = 0.01), troponin I (37 ± 28 versus 99 ± 12, p = 0.005) and CK-MB (11 ± 4 versus 20.1 ± 5, p = 0.031) at 24-h after ROSC. ROSC was achieved in 4/6 animals only after reperfusion in group C.

Conclusions

Early reperfusion after ischemic cardiac arrest improved 24 h survival rate and neurological function. In animals with refractory VF, reperfusion was necessary to achieve ROSC.     

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.     

Evaluation of the 2010 American Heart Association Guidelines for infant CPR finger/thumb positions for chest compression: A study using computed tomography

Introduction

We sought to verify, using computed tomography (CT) examinations of infants, which the left ventricle (LV) is compressed and abdominal compression avoided by using the chest compression landmarks recommended by the 2010 American Heart Association (AHA) Guidelines for infant cardiopulmonary resuscitation (CPR).

Methods

Using CT examinations of 63 infants performed between March 2002 and July 2011, we retrospectively measured the distance between the INL and the xiphoid process, and the distance of the lower third (LT) of the sternum. The distances between LV maximal diameter (LVMD) and xiphoid processes were also measured to determine whether LVs would be compressed by chest compressions. These distances were compared with the finger placements by 20 adults, when placed on infant mannequins for simulated two-finger or two-thumb infant CPR.

Results

The mean distances of the INL and the LT of the sternum were 32 ± 8 mm and 12 ± 2 mm from the xiphoid, respectively. The LVMD was placed 15 ± 6 mm from the xiphoid process. When we overlaid the width of adult finger placement (a mean of 28 mm for two-finger technique, and 23 mm for two-thumb technique), the LV was compressed in 57 patients (90.5%) and 59 patients (93.7%), respectively. The upper abdomen was compressed in 22 patients (34.9%) by the two-finger technique and in 16 patients (25.3%) by the two-thumb technique with the range of 0.3–10.8 mm.

Conclusion

When applying the 2010 AHA Guidelines for infant CPR, recommended finger placement allows for adequate compression of the LV in more than 90% of patients. In 23–35% of infants, the upper abdomen is compressed from 0.3 mm to 10.7 mm.     

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)