Part 3: adult basic life support. European Resuscitation Council

Accuracy of breathing and radial pulse assessment by non-medical persons: an observational cross-sectional study

Early recognition of cardiopulmonary arrest (CPA) expedites emergency calls and resuscitation and improves the survival rate of unresponsive individuals. However, the accuracy of breathing and radial artery pulse assessment by non-medical persons is poorly understood. The aim of this study was to determine the accuracy of breathing assessment and radial pulse palpation among 450 non-medical personnel using a high-fidelity simulator. We examined the accuracy of 10 second's assessment for breathing and radial pulse using a high-fidelity mannequin simulator, included 496 non-medical participants (school teachers) between 2016-2018. For a primary results, the sensitivity for the detection of the presence of the breathing and radial pulse was 96.2% (97.5% for sensitivity and 92.0% for specificity) and 91.7% (99.1% for sensitivity and 56.8% for specificity), respectively. Futher, breathing rate and radial pulse rate were strongly correlated with the assessments, with Spearman's correlation coefficients of 0.813 (P < 0.001) and 0.719 (P < 0.001), respectively. In contrast, radial pulse strength was weakly correlated with the assessment (coefficient of 0.288, P < 0.001). Our results suggested that non-medical persons would show high accuracy in detecting and measuring respiration and radial pulse, although they did not accurately determine radial pulse strength for the early recognition of CPA.

[Basic life support]

The European Resuscitation Council has produced these basic life support guidelines, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics covered include cardiac arrest recognition, alerting emergency services, chest compressions, rescue breaths, automated external defibrillation (AED), cardiopulmonary resuscitation (CPR) quality measurement, new technologies, safety, and foreign body airway obstruction.

European Resuscitation Council Guidelines 2021: Basic Life Support

The European Resuscitation Council has produced these basic life support guidelines, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics covered include cardiac arrest recognition, alerting emergency services, chest compressions, rescue breaths, automated external defibrillation (AED), CPR quality measurement, new technologies, safety, and foreign body airway obstruction.

Chest compression components (rate, depth, chest wall recoil and leaning): A scoping review

AIM

To understand whether the science to date has focused on single or multiple chest compression components and identify the evidence related to chest compression components to determine the need for a full systematic review.

METHODS

This review was undertaken by members of the International Liaison Committee on Resuscitation and guided by a specific methodological framework and the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR). Studies were eligible for inclusion if they were peer-reviewed human studies that examined the effect of different chest compression depths or rates, or chest wall or leaning, on physiological or clinical outcomes. The databases searched were MEDLINE complete, Embase, and Cochrane.

RESULTS

Twenty-two clinical studies were included in this review: five observational studies involving 879 patients examined both chest compression rate and depth; eight studies involving 14,285 patients examined chest compression rate only; seven studies involving 12001 patients examined chest compression depth only, and two studies involving 1848 patients examined chest wall recoil. No studies were identified that examined chest wall leaning. Three studies reported an inverse relationship between chest compression rate and depth.

CONCLUSION

This scoping review did not identify sufficient new evidence that would justify conducting new systematic reviews or reconsideration of current resuscitation guidelines. This scoping review does highlight significant gaps in the research evidence related to chest compression components, namely a lack of high-level evidence, paucity of studies of in-hospital cardiac arrest, and failure to account for the possibility of interactions between chest compression components.

The International Liaison Committee on Resuscitation-Review of the last 25 years and vision for the future

2017 marks the 25th anniversary of the International Liaison Committee on Resuscitation (ILCOR). ILCOR was formed in 1992 to create a forum for collaboration among principal resuscitation councils worldwide. Since then, ILCOR has established and distinguished itself for its pioneering vision and leadership in resuscitation science. By systematically assessing the evidence for resuscitation standards and guidelines and by identifying national and regional differences, ILCOR reached consensus on international resuscitation guidelines in 2000, and on international science and treatment recommendations in 2005, 2010 and 2015. However, local variation and contextualization of guidelines are evident by subtle differences in regional and national resuscitation guidelines. ILCOR's efforts to date have enhanced international cooperation, and progressively more transparent and systematic collection and analysis of pertinent scientific evidence. Going forward, this sets the stage for ILCOR to pursue its vision to save more lives globally through resuscitation.

Impact of basic life-support training on the attitudes of health-care workers toward cardiopulmonary resuscitation and defibrillation

BACKGROUND

Cardiopulmonary resuscitation (CPR) increases the probability of survival of a person with cardiac arrest. Repeating training helps staff retain knowledge in CPR and in use of automated external defibrillators (AEDs). Retention of knowledge and skills during and after training in CPR is difficult and requires systematic training with appropriate methodology. The aim of this study was to determine the effect of basic life-support (BLS) training on the attitudes of health-care providers toward initiating CPR and on use of AEDs, and to investigate the factors that influence these attitudes.

METHODS

A quasi-experimental study was conducted in two groups: health-care providers who had just attended a BLS-AED course (post-BLS group, n = 321), and those who had not (pre-BLS group, n = 421). All participants had previously received BLS training. Both groups were given a validated questionnaire to evaluate the status of life-support education and certification, attitudes toward use of CPR and AED and concerns regarding use of CPR and AED. Multiple linear regression analyses were applied to identify significant predictors of the attitude and concern scores.

RESULTS

Overall positive attitudes were seen in 53.4% of pre-BLS respondents and 64.8% of post-BLS respondents (χ² = 9.66, p = 0.002). Positive attitude was significantly predicted by the recent completion of BLS training (β = 5.15, p < 0.001), the number of previous BLS training courses (β = 2.10, p = 0.008) and previous exposure to cardiac-arrest cases (β = 3.44, p = 0.018), as well as by low concern scores, (β = -0.09, p < 0.001). Physicians had significantly lower concern scores than nurses (β = -10.45, p = 0.001). Concern scores decreased as the duration of work experience increased (t = 2.19, p = 0.029).

CONCLUSIONS

Repeated educational programs can improve attitudes toward CPR performance and the use of AEDs. Training that addressed the concerns of health-care workers could further improve these attitudes.

i-gel™ in Ambulatory Surgery: A Comparison with LMA-ProSeal™ in Paralyzed Anaesthetized Patients

INTRODUCTION

Supraglottic devices have mostly eliminated the need of hemodynamically stressful routine endotracheal intubation for ambulatory surgeries. We aimed to compare hemodynamics- like blood pressure (BP) and heart rate (HR) alterations caused by stress response due to i-gel™ and LMA-ProSeal™ usage in Day care surgeries. Secondary outcomes included ease of insertion, time and number of attempts for the placement of devices.

MATERIALS AND METHODS

From April 2008 to July 2009, Sixty adult ASA I-II patients of either sex, aged 20-30, were randomly allocated into two groups (Group i-gel (n=30) receiving i-gel and Group PLMA (n=30) receiving LMA-ProSeal for airway maintenance) undergoing day care surgical procedures under general anaesthesia (GA).The ease of insertion and time taken for placement of device, postoperative complications were assessed. Haemodynamic parameters (HR, BP) were noted. It was a prospective, double blinded, and randomized controlled study. Parametric data were analyzed with the unpaired t-test and non-parametric data were analyzed with the Chi-square test. Unless otherwise stated, data are presented as mean (+ SD). p <0.05 was considered statistically significant.

RESULTS

Demographically both the groups were similar. i-gel was more easily inserted than LMA-ProSeal (90% vs. 83.33% respectively). i-gel insertion time was shorter than PLMA (14.9 vs. 20.0 sec respectively) and was statistically significant. Hemodynamics (HR, BP) were less altered in i-gel than PLMA and the results were statistically significant (p <0.05).

CONCLUSION

i-Gel; a relatively newer and cheap supraglottic device; insertion is easier and quicker as well as hemodynamically less stressful when compared with LMA-ProSeal in a day care setting.

[Theoretical training for nurses in cardiac arrest attendance]

OBJECTIVES OF THE STUDY

to apply a theoretical qualification program for nurses in cardiopulmonary resuscitation and compare the theoretical knowledge group-A-control with group-B-experimental. This program comprised three stages: Stage-I, evaluation pre-theoretical qualification; Stages-II and III, evaluation of the recent (one week after stage-I) and later (three months after stage-I) qualification. The sample was composed of 21 nurses in Group-A and 38 in Group-B. The mean performance score in Group-A varied in a progressive form: 6.45; 6.66 and 7.10; in Group-B, in an oscillating form: 6.48; 8.36 and 8.0; stages II and III (p<0,001). It was concluded that: Group-B has been superior to Group-A. However, the performance of Group-B stage-II was superior to stage-III, while in the Group-A it was observed a gradual improvement.

Comparison of the quality of chest compressions on a dressed versus an undressed manikin: A controlled, randomised, cross-over simulation study

BACKGROUND

Undressing the chest of a cardiac arrest victim may delay the initiation of chest compressions. Furthermore, expecting laypeople to undress the chest may increase bystander reluctance to perform cardiopulmonary resuscitation (CPR). Both of these factors might conceivably decrease survival following cardiac arrest. Therefore, the aim of this study was to examine if the presence or absence of clothes affected the quality of chest compressions during CPR on a simulator manikin.

METHODS

Thirty laypeople and 18 firefighters were randomised to start CPR on the thorax of a manikin that was either clothed (three layers) or not. Data were obtained via recordings from the manikin and audio- and video-recordings. Measurements were: maximum compression depth; compression rate; percentage of compressions with correct hand positioning; percentage of compressions with complete release (< or = 10 mm), and percentage of compressions of the correct depth (range 40-50 mm). Laypeople were given a four-hour European Resuscitation Council standardised course in basic life support and tested immediately after. Firefighters were tested without additional training. Mock cardiac arrest scenarios consisted of three minutes of CPR separated by 15 minutes of rest.

RESULTS

No significant differences were found between CPR performed on an undressed manikin compared to a dressed manikin, for laypeople or firefighters. However, undressing the manikin was associated with a mean delay in the initiation of chest compressions by laypeople of 23 seconds (N = 15, 95% CI: 19;27).

CONCLUSIONS

In this simulator manikin study, there was no benefit gained in terms of how well CPR was performed by undressing the thorax. Furthermore, undressing the thorax delayed initiation of CPR by laypeople, which might be clinically detrimental for survival.

Shortening of cardiopulmonary resuscitation time before the defibrillation worsens the outcome in out-of-hospital VF patients

OBJECTIVE

The purpose of the study is to investigate the influence of cardiopulmonary resuscitation (CPR) time before the first defibrillation.

METHODS

The present study retrospectively analyzed the Utstein template records from April 1, 2002, to June 30, 2005. Patients who had out-of-hospital-witnessed cardiac arrest caused by cardiac disease and who presented with ventricular fibrillation (VF) as the initial cardiac rhythm were included in the study. Before April 1, 2003, the emergency medical technician (EMT) needed to obtain telephone permission before attempting defibrillation, and CPR was continued until permission was received (CPR first). On and after April 1, 2003, the EMT was immediately able to attempt a defibrillation without obtaining permission (shock first).

RESULTS

In 143 patients who had out-of-hospital-witnessed VF, 43 patients and 100 patients were treated with the CPR-first strategy and the shock-first strategy, respectively. The duration of CPR before the first defibrillation was longer in the CPR-first group than that in the shock-first group. The CPR-first group showed a higher rate of favorable neurologic outcome 30 days after (28% vs 14%; P = .048) and 1 year after cardiac arrest (26% vs 11%; P = .033) than those of the shock-first group. In the patients with witnessed VF, a stepwise multiple logistic regression analysis showed the CPR-first strategy to improve the neurologic outcome.

CONCLUSIONS

In patients with out-of-hospital-witnessed VF, sufficient CPR before the first defibrillation is considered to improve the neurologic outcome in comparison to the performance of immediate defibrillation.

Fire fighters as basic life support responders: a study of successful implementation

BACKGROUND

First responders are recommended as a supplement to the Emergency Medical Services (EMS) in order to achieve early defibrillation. Practical and organisational aspects are essential when trying to implement new parts in the "Chain of Survival"; areas to address include minimizing dispatch time, ensuring efficient and quick communication, and choosing areas with appropriate driving distances. The aim of this study was to implement a system using Basic Life Support (BLS) responders equipped with an automatic external defibrillator in an area with relatively short emergency medical services' response times. Success criteria for implementation was defined as arrival of the BLS responders before the EMS, attachment (and use) of the AED, and successful defibrillation.

METHODS

This was a prospective observational study from September 1, 2005 to December 31, 2007 (28 months) in the city of Aarhus, Denmark. The BLS responder system was implemented in an area up to three kilometres (driving distance) from the central fire station, encompassing approximately 81,500 inhabitants. The team trained on each shift and response times were reduced by choice of area and by sending the alarm directly to the fire brigade dispatcher.

RESULTS

The BLS responders had 1076 patient contacts. The median response time was 3.5 minutes (25th percentile 2.75, 75th percentile 4.25). The BLS responders arrived before EMS in 789 of the 1076 patient contacts (73%). Cardiac arrest was diagnosed in 53 cases, the AED was attached in 29 cases, and a shockable rhythm was detected in nine cases. Eight were defibrillated using an AED. Seven of the eight obtained return of spontaneous circulation (ROSC). Six of the seven obtaining ROSC survived more than 30 days.

CONCLUSION

In this study, the implementation of BLS responders may have resulted in successful resuscitations. On basis of the close corporation between all participants in the chain of survival this project contributed to the first link: short response time and trained personnel to ensure early defibrillation.

Arterial blood gases during basic life support of human cardiac arrest victims

BACKGROUND

Ventilation with tidal volumes sufficient to raise the victim's chest is an integral part of guidelines for lay-rescuer basic life support, but optimal tidal volume, frequency and ratio to chest compressions are not known.

METHODS

Adults with non-traumatic, out-of-hospital cardiac arrest, who were not successfully resuscitated following advanced life support by the staff of a physician-manned ambulance, were included. Advanced life support comprised tracheal intubation and mechanical ventilation with tidal volume of 700 ml and 100% oxygen, 12 times per min. An arterial blood sample was drawn at the end of the resuscitation attempt and analysed on the scene. After the victim was declared dead, basic life support was initiated with chest compressions and mouth-to-mask or mouth-to-tracheal tube ventilation (15:2), with volumes sufficient to make the chest rise. The tracheal tube was equipped with an impedance valve to avoid passive ventilation secondary to chest compressions. Arterial blood samples were drawn after 7-8 min of basic life support and analysed on the scene.

RESULTS

Six men and two women, median (range) age 72 (32-86) years, were included in the study. Four of these received mouth-to-mask ventilation and four mouth-to-tracheal tube ventilation. Mean (S.D.) arterial blood carbon dioxide and oxygen tension during advanced life support were 6.4 (1.4)kPa and 22 (15)kPa, respectively. Similar values during basic life support were 9.6 (1.9)kPa and 8.5 (1.6)kPa, respectively, with no differences between the ventilation methods.

CONCLUSION

Ventilation during basic life support performed according to international guidelines (2000) resulted in arterial hypercapnia and hypoxia.

Pre-hospital trauma care

The chain of survival in outcome from major trauma is equally as important as its well established concept in survival from cardiac arrest. Preventive measures have been shown to be an effective means of reducing death from trauma, and the standard of pre-hospital care for those surviving the primary injury is improving in many trauma systems. The optimal pre-hospital interventions are still debated, but evidence suggests that patients with severe head injury in particular will benefit significantly from pre-hospital rapid-sequence intubation and field stabilization, whereas those with penetrating injury require rapid evacuation to hospital with minimal intervention. Pre-hospital asystole from trauma has a universally poor outcome. When delivering appropriate care, several helicopter-based systems have shown improvements in outcome compared with ground-based systems. The International Liaison Committee on Resuscitation recently published guidelines on resuscitation, with particular relevance to pre-hospital trauma care. The importance of bystander cardiopulmonary resuscitation, oxygenation, and the avoidance of iatrogenic morbidity are stressed.

An evaluation of objective feedback in basic life support (BLS) training

BACKGROUND

Studies show that acquisition and retention of BLS skills is poor, and this may contribute to low survival from cardiac arrest. Feedback from instructors during BLS training is often lacking. This study investigates the effects of continuous feedback from a manikin on chest compression and ventilation techniques during training compared to instructor feedback alone.

MATERIALS AND METHODS

A prospective randomised controlled trial. First-year healthcare students at the University of Birmingham were randomised to receive training in standard or feedback groups. The standard group were taught by an instructor using a conventional manikin. The feedback group used a 'Skillreporter' manikin, which provides continuous feedback on ventilation volume and chest compression depth and rate in addition to instructor feedback. Skill acquisition was tested immediately after training and 6 weeks later.

RESULTS

Ninety-eight participants were recruited (conventional n=49; Skillreporter n=49) and were tested after training. Sixty-six students returned (Skillreporter n=34; conventional n=32) for testing 6 weeks later. The Skillreporter group achieved better compression depth (39.96mm versus 36.71mm, P<0.05), and more correct compressions (58.0% versus 40.4%, P<0.05) at initial testing. The Skillreporter group also achieved more correct compressions at week 6 (43.1% versus 26.5%, P<0.05).

CONCLUSIONS

This study demonstrated that objective feedback during training improves the performance of BLS skills significantly when tested immediately after training and at re-testing 6 weeks later. However, CPR performance declined substantially over time in both groups.

A prospective manikin-based observational study of telephone-directed cardiopulmonary resuscitation

INTRODUCTION

Bystander cardiopulmonary resuscitation (CPR) significantly improves the outcome from sudden cardiac arrest (SCA) and is therefore encouraged by offering telephone instructions to the bystander. The effectiveness of this technique was examined in a manikin-based study.

METHODS

Subjects performed CPR on an instrumented adult manikin by following Advanced Medical Priority Dispatch System v11.1 (AMPDS) instructions given by telephone from a different room.

RESULTS

Fifty-one volunteers (26 males, median age 56, range 27-76 years) with no previous experience of CPR were recruited. No volunteers followed the entire instructions correctly. Forty percent were unable to open the airway, only 18% achieved a median inspiration time of 2 s or greater and only 30% delivered tidal volumes within the range 700-1000 ml. Chest compressions were performed at a median rate of 52 min-1 with only 4% of subjects achieving a rate of 100 min-1. Depth of compression was also inadequate in 88% of subjects and hand positioning was incorrect in a third of subjects. The median duty cycle was 46% and there were significant delays between the commencement of the AMPDS protocol and the delivery of the first breath (123 s) and first chest compression (163 s).

DISCUSSION

Few bystanders perform CPR satisfactorily and further work is necessary to improve the effectiveness of telephone CPR instructions.

Assessment of the quality of cardiopulmonary resuscitation following modification of a standard telephone-directed protocol

INTRODUCTION

Current Advanced Medical Priority Dispatch System (AMPDS) V.11.1 telephone instructions are limited in their ability to produce correctly performed basic life support. The current telephone instructions were modified in an attempt to improve areas of poor CPR performance.

METHODS

Fifty subjects performed CPR on an instrumented adult manikin by following instructions modified from AMPDS V.11.1 instructions. Instructions were given by telephone from a different room.

RESULTS

No improvements were seen with opening the airway or delivering rescue breaths. The rate of chest compression improved from 52 to 81 min-1 (P=0.004), although the depth of chest compression fell to 2.0 cm compared with 3.2 cm documented with the original AMPDS instructions (P=0.004). Instructions to put the telephone down while performing CPR improved all aspects of CPR.

DISCUSSION

The effective delivery of telephone-directed CPR to untrained bystanders is a complex process. Changing verbal instructions to improve the quality of CPR is not easy. Further work is urgently needed to strengthen this important link in the chain of survival.

Teaching recognition of agonal breathing improves accuracy of diagnosing cardiac arrest

OBJECTIVE

Agonal breathing is present in up to 40% of pre-hospital cardiac arrests and is commonly mistaken as a sign of circulation leading to omission of bystander resuscitation. The aim of this study was to test the hypothesis that specific tuition on agonal breathing improves the accuracy of checking for signs of circulation as a diagnostic test for cardiac arrest.

METHODS

First year medical students were randomised to control or intervention groups. The control group were taught standard CPR according to current guidelines. The intervention group received standard CPR training plus specific tuition on the characteristics of agonal breathing. Two weeks after initial training, the students' ability to recognise cardiac arrest was tested using a simulated cardiac arrest victim demonstrating normal, absent or agonal breathing. Diagnostic accuracy, sensitivity and specificity for the decision to start CPR was calculated.

RESULTS

Sixty-four students were equally randomised to intervention and control groups. The intervention group had greater diagnostic accuracy for cardiac arrest compared to the control group (90% versus 78%, P=0.03). The intervention group were more likely to recognise cardiac arrest correctly and initiate CPR than the control group (sensitivity 90% versus 78%, P=0.02). The improved results were predominantly due to recognition that agonal breathing is a sign of cardiac arrest (75% intervention group versus 43% control group, P=0.01).

CONCLUSION

This study demonstrates improved diagnostic accuracy and sensitivity of "checking for signs of circulation" by teaching CPR providers to recognise agonal breathing as a sign of cardiac arrest.

Assessing proficiency in adult basic life support: student and expert assessment and the impact of video recording

Self-assessment is an important aspect in the development of lifelong learning skills for medical students, crucial to maintaining a high level of competence in practice. Basic Life Support (BLS) is a skill that all health professionals must acquire and maintain competence in. This paper reports data from a study of 95 first-year graduate entry medical students at Flinders University in Australia, determining how well the students could assess their own BLS performance. These students were videotaped performing a short CPR scenario using a Resusci Anne with SkillReporter (Laerdal, Norway). Using a six-point descriptive ratings scale, students graded themselves twice: once immediately after completing the task, and again after viewing a video of their performance. A single expert assessor viewed all the video recordings and, based on International Liaison Committee on Resuscitation (ILCOR) Guidelines, graded the students using the same scale. The hypothesis was that the intervention of viewing their performance on video would improve the correlation of their ratings with the expert assessor. The results showed that the students' assessments did not agree with the expert assessor either before (weighted kappa = 0.03) or after seeing the video (weighted kappa = 0.002). Possible reasons, including student attitudes and lack of benchmarking, are discussed. Self-assessment skills of students warrant further attention.

Bystander mouth-to-mouth ventilation and regurgitation during cardiopulmonary resuscitation

OBJECTIVES

To determine whether there is an association between bystander mouth-to-mouth ventilation and regurgitation in prehospital cardiac arrest patients.

DESIGN

Prospectively conducted observational study.

SETTING

Data were collected from patients treated by the emergency medical service (EMS) systems in three middle-sized or large Finnish urban communities, the Tampere District EMS and the physician-staffed Helicopter EMSs in the Helsinki and Turku areas in southern Finland.

SUBJECTS

The study population consisted of 529 consecutive prehospital cardiac arrest patients with attempted resuscitation. Exclusion criteria were cardiac arrest due to trauma or drug overdose.

MAIN OUTCOME MEASURES

Regurgitation in prehospital cardiac arrest patients documented by EMS personnel on the scene.

RESULTS

Regurgitation occurred in a fourth of patients. Bystander cardiopulmonary resuscitation (CPR) with mouth-to-mouth ventilation was associated with a significantly increased risk of regurgitation compared with no CPR (P < 0.013) and CPR without ventilations (P < 0.01).

CONCLUSIONS

The mode and role of bystander CPR in cardiac arrest needs to be further evaluated.

Comparison of mouth-to-mouth, mouth-to-mask and mouth-to-face-shield ventilation by lay persons

OBJECTIVE AND METHODS

A prospective randomised study on 70 volunteers without previous first aid education (42 males, 28 females, mean age 17) was performed to compare mouth-to-mouth ventilation (MMV, n = 24) versus mouth-to-pocket-mask ventilation (MPV, n = 25) and mouth-to-face-shield ventilation (MFV, n =21), and to evaluate if an instruction period of 10 min would be sufficient to teach lay persons artificial ventilation. Every volunteer performed three ventilation series using a bench model of an unprotected airway.

RESULTS

MMV and MPV show higher mean tidal volume (TV) than MFV (values of series 3: 976 +/- 454 and 868 +/- 459 versus 604 +/- 328 ml, P = 0.002 and P = 0.025, respectively). We found a higher inter-individual variation in TV than in previous studies (P = 0.031). The recommended TV of 700-1000 ml was reached in only 23%, most frequently with MPV (MMV 16.7%, MPV 32%, MFV 19%) but the difference was not significant (P = 0.391). However, we found a significantly higher percentage with a TV below 700 ml with MFV (MMV 33.3%, MPV 36%, MFV 66.7% P = 0.047) and a significantly higher percentage of TV exceeding 1000 ml with MMV (MMV 50%, MPV 32%, MFV 14.3%) (P = 0.039). "Stomach" inflation was highest with MMV (79.2%) followed by MPV (52%) and MFV (42.9%) (P = 0.034). We found further differences between the sexes; males produced a higher TV (P = 0.003) and a higher percentage of stomach inflation (P = 0.029).

CONCLUSION

MPV showed the best ventilation quality. It resulted in a more adequate TV than MMV and MFV and lower stomach inflation than MMV. Only a relatively low percentage of ventilations were within the recommended range for TV and this may be related to the short training duration. We found different performances between the sexes, a high inter-individual variation and mainly a low ventilation quality. Therefore, further studies have to focus more on teaching duration, sex differences and ventilation quality.

New airways for resuscitation?

Over the last 15 years supraglottic airway devices (SADs), most notably the classic laryngeal mask airway (LMA) have revolutionised airway management in anaesthesia. In contrast for resuscitation, both in and outside hospital, facemask ventilation and tracheal intubation remain the mainstays of airway management. However there is evidence that both these techniques have complications and are often poorly performed by inexperienced personnel. Tracheal intubation also has the potential to cause serious harm or death through unrecognised oesophageal intubation. SADs may have a role in airway management for resuscitation as first responder devices, rescue devices or for use during patient extraction. In particular they may be beneficial as the level of skill required to use the device safely may be less than for the tracheal tube. Concerns have been expressed over the ability to ventilate the lungs successfully and also the risk of aspiration with SADs. The only SADs recommended by ILCOR in its current guidance are the classic LMA and combitube. Several SADs have recently been introduced with claims that ventilation and airway protection is improved. This pragmatic review examines recent developments in SAD technology and the relevance of this to the potential for using SADs during resuscitation. In addition to examining research directly related to resuscitation both on bench models and in patients the review also examines evidence from anaesthetic practice. SADS discussed include the classic, intubating and Proseal LMAs, the combitube, the laryngeal tube, laryngeal tube sonda mark I and II and single use laryngeal masks.

Advanced cardiac life support before and after tracheal intubation—direct measurements of quality

STUDY HYPOTHESIS

Tracheal intubation should improve the quality of cardiopulmonary resuscitation (CPR) by enabling adequate ventilation without pauses in external chest compressions.

METHODS

Out-of-hospital cardiac arrests of all causes were sampled in this non-randomized, observational study of advanced cardiac life support in three ambulance services (Akershus, London and Stockholm). Prototype defibrillators (Heartstart 4000SP, Philips Medical Systems, Andover, MA, USA and Laerdal Medical AS, Stavanger, Norway) registered all chest compressions via an extra chest pad with an accelerometer mounted over the lower part of sternum and ventilations from changes in transthoracic impedance between the standard defibrillator pads. The quality of CPR was analyzed off-line for 119 episodes. Numbers and differences are given as mean +/- S.D. and differences as mean and 95% confidence intervals.

RESULTS

Chest compressions were not given in cardiac arrest for 61 +/- 20% of the time before intubation compared to 41 +/- 18% after intubation (difference: 20% (16-24%)). Compressions and ventilations per minute increased from 47 +/- 25 to 71 +/- 23 (difference: 24 (19, 29)) and 5.6 +/- 3.7 to 14 +/- 5.0 (difference: 8.7 (7.6, 9.8)) respectively. Four cases of unrecognized oesophageal intubation (3%) were suspected from the disappearance of ventilation induced changes in thoracic impedance after intubation.

CONCLUSION

The quality of CPR improved after tracheal intubation, but the fraction of time without blood flow was still high and not according to international guidelines. On-line analysis of thoracic impedance might be a practicable aid to avoid unrecognized oesophageal intubation, but this area needs further research.

Erfolgreiche Reanimation nach Frühdefibrillation durch Pistendienst

Life-threatening incidents during leisure sport activities are not uncommon and also cardiovascular problems are occurring with ever-increasing frequency during alpine downhill skiing. Because these are emergency situations which regularly occur in distant or at least not easily accessible areas, assistance from lay persons can be the decisive factor for survival. The report describes a case of cardiopulmonary resuscitation of a skier in alpine terrain, who survived a cessation of circulation without sequelae after rapid defibrillation by maintenance personnel. A review of possibilities for improved emergency medical care in mountainous regions is also given.

Comparison of effects of different hand positions during cardiopulmonary resuscitation

AIM

The technique of chest compression recommended in the recent international guidelines is different from that which was traditionally used in Hungary. While compression force, location, frequency and duty cycle are all identical, the position of the hand on the chest is different. The aim of our study was to compare these two methods concerning the area and location of the surface compressed on the chest wall.

METHODS

Thirty-eight doctors were trained in both compression methods. Compressions were carried out on an AMBU Man-C manikin. The compressed surface, marked by using a carbon paper, was projected on to a standardised 10 mm x 10 mm matrix to measure the area and location. The chest surface was marked subsequently as green, yellow and red areas to identify the correct position, incorrect position and dangerous areas. All subjects did chest compressions using both techniques (I, International; H, traditional Hungarian) in a random order each for 30 s.

RESULTS

The surface area compressed was significantly larger by the H method than the I method (73.46 (+/-17.11) versus 41.75 (+/-11.08), p<0.005). 8.07 (+/-1.91) cm2 of an area considered dangerous were compressed by the H method compared to 2.93 (+/-0.78) cm2 by the I method (p<0.005).

CONCLUSION

Comparing the two different methods of chest compressions, the hand position recommended by the recent international guidelines seems to be more safe as it compresses a smaller area which might cause injury.

Over-the-head cardiopulmonary resuscitation improves efficacy in basic life support performed by professional medical personnel with a single rescuer: a simulation study

Two-rescuer cardiopulmonary resuscitation (CPR) is considered the best method for professional basic life support (BLS). However, in many prehospital cardiac arrest situations, one rescuer has to begin CPR alone while the other performs additional tasks. In theory, over-the-head CPR is a suitable alternative in this situation, with the added benefit of allowing the single rescuer to use a self-inflating bag for ventilation. In this trial, we compared standard single-rescuer CPR with over-the-head CPR in manikins. We planned this study using a crossover study design where each participant administered both CPR techniques in a randomized order. Ventilation and chest compression data were collected with analysis software during a 2-min CPR test for each technique. Sixty-seven emergency medical technician students participated in this trial. Over-the-head CPR allowed for superior ventilation compared to standard CPR (number of correct ventilations: 330 of 760 versus 279 of 779; P = 0.002). The quality of delivered chest compressions did not differ between the two groups (correct chest compressions: 4293 of 6304 versus 4313 of 6395; P = 0.44). In conclusion, our study has shown that over-the-head CPR may be an effective alternative BLS technique when a single professional rescuer has to perform CPR, likely offering superior ventilation and comparable chest compression quality compared with standard BLS.

[Resuscitation in ventricular fibrillation: what is essential?]

Prognosis of prehospital cardiac arrest due to ventricular fibrillation is dependent on the first minutes, as survival decreases by 10% for each minute by which resuscitation attempts are delayed. Thus, early defibrillation plays a key role in improving outcome of cardiac arrest victims. The effectiveness of automated external defibrillators (AEDs) in this setting has been proven by several clinical trials. There remains controversy with regard to using AEDs in the in-hospital setting, as well as the approach of "public access" defibrillation. Whereas the use of intravenous antiarrhythmic drugs, particularly amiodarone, remains controversial, new data support the use of vasopressine instead of epinephrine as vasopressor drug in cardiac arrest patients. The present review aims to focus on the above mentioned aspects as well as on the changes to the present ILCOR guidelines which have led to modification of the resuscitation guidelines of the European Resuscitation Council (ERC).

In-water resuscitation: a pilot evaluation

INTRODUCTION

The first and most important treatment for the apnoeic drowning victim is the rapid alleviation of hypoxia by artificial ventilation. Recent studies have suggested that commencing resuscitative efforts with the victim still in the water may be beneficial. The aim of this pilot study was to evaluate the feasibility and efficacy of in-water unsupported rescue breathing.

METHODS

Three lifeguards were taught how to perform in-water unsupported rescue breathing. Ventilation volume, inflation duration were recorded from a modified Laerdal resuscitation manikin. The rescue duration was recorded and compared to a rescue undertaken without in-water resuscitation.

RESULTS

The three lifeguards performed between seven and nine ventilations during each simulated rescue. This gave average inflation volumes for each lifeguard of 711 ml (S.D. 166), 750 ml (S.D. 108), 629 ml (S.D. 182) and average inflation duration of 0.8s (S.D. 0.3), 0.9s (S.D. 0.2) and 0.6s (S.D. 0.1). The rescue duration was increased from an average time of 1 min 10 s to 1 min 24 s by performing in-water resuscitation.

CONCLUSION

This study has demonstrated the feasibility and potential efficacy of in-water unsupported rescue breathing with a victim in deep water. Furthermore, the technique was not associated with an undue prolongation of the rescue duration over a 50 m rescue. In circumstances where the trained lifeguard finds themselves with an apnoeic victim in the water, with no buoyant rescue aid available, they may consider the application of in-water, unsupported rescue breathing, especially if recovery to dry land is likely to be delayed. The effectiveness of this technique, however, remains to be proven in the open water environment.

Two-rescuer CPR results in hyperventilation in the ventilating rescuer

The "Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care--International Consensus on Science" recommend a tidal ventilation volume of 10 ml/kg body-weight without the use of supplemental oxygen during two-rescuer adult cardiopulmonary resuscitation (CPR). This relates to a ventilation volume of about 6.4 l/min. Additionally, the first aid provider ventilating the victim will breathe for him/herself during the external chest compression period adding another 3.2 l/min of ventilation. Finally, a deep breath is recommended before each ventilation to increase the end-expiratory oxygen concentration of the air exhaled. To investigate the effects of these recommendations, 20 healthy volunteers were asked to perform two-rescuer CPR in a lung model connected to a BLS-manikin. End-tidal carbon dioxide, oxygen saturation, and heart rate were recorded continuously. Capillary blood gas samples were collected and non-invasive blood pressure was recorded prior to the start of external chest compressions and immediately after the end of each measurement period. Furthermore, hyperventilation related symptoms reported by the volunteers were also recorded. The data reveal a significant decrease in capillary and end-tidal carbon dioxide pressure in the volunteers (P < 0.001). Additionally, in 75% of test persons multiple hyperventilation associated symptoms occurred. Ventilation during two-rescuer CPR performed according to the Guidelines 2000 may cause injury to the health of first aid providers. To minimize hyperventilation, both rescuers should exchange their positions at intervals of 3-5 min. These data challenge the recommendation to take a deep breath prior to each ventilation.

Differences in time to defibrillation and intubation between two different ventilation/compression ratios in simulated cardiac arrest

OBJECTIVE

During basic life support (BLS) by a two-rescuer-team early defibrillation and ALS procedures should be performed without interruptions of the BLS-ventilation/compression sequence. The objective of this study was to determine the impact of a ventilation/compression ratio of 5:50 versus 2:15 on the time intervals "Start BLS to first shock" and "Start BLS to intubation".

METHODS

Using a random cross over design 40 experienced paramedics performed a standard BLS/ALS-algorithm according to ILCOR guidelines in a manikin model with ventricular fibrillation (resusci skillreporter anne, Laerdal, Norway) performing both the 2:15 and the 5:50 ventilation/compression ratio. BLS was started with bag/valve/mask ventilation, a semi-automatic defibrillator (corpuls 08/16S) was connected with the manikin, ECG-analysis and three shocks were performed and the tracheal intubation was prepared. Ventilation/compression sequence was only interrupted during ECG-analysis and defibrillation. Expiratory volumes and number of compressions were measured. Variables were compared using paired Students t-test. In addition paramedics were interviewed about work-flow and emotional stress during the tests.

RESULTS

The time interval "Start BLS to first shock" was 78 s (2:15-group) versus 63 s (5:50-group), p<0.0001, the time interval "Start BLS to intubation" was 183 s (2:15-group) versus 150 s (5:50-group), p<0.0001, mean ventilation volumes per minute were 4490 ml (2:15-group) versus 4370 ml (5:50-group), p>0.1, mean number of compressions were 65 min-1. (2:15-group) versus 68 min-1 (5:50-group), p>0.1. The work-flow and emotional stress was appraised by the paramedics to be significantly superior in the 5:50 ratio (p<0.0001).

CONCLUSIONS

The ventilation/compression ratio of 5:50 compared with 2:15 during BLS with an unsecured airway reduces the time until the first defibrillation and tracheal intubation was performed without changes in ventilation volume and compressions per minute. The Paramedics stated that the 5:50 ratio improved the work-flow and reduced the emotional stress.

[Resuscitation after prehospital cardiovascular arrest]

Initiation of effective cardiopulmonary resuscitation (CPR) at the earliest possible moment is the most important determinant of prognosis for prehospital cardiac arrest. The prognosis is essentially defined by two parameters: survival to hospital admission and survival to discharge. In connection with prehospital cardiac arrest, early defibrillation is particularly important, including the widespread availability of (semi)automatic defibrillators. Further aspects of CPR have recently received increased attention: on the one hand, changed study status regarding the use of antiarrhythmic agents (especially amiodarone), on the other hand, administration of vasopressin during resuscitation, and finally, the efficacy of mild hypothermia following prehospital cardiac arrest. These aspects represent the main subject of the present overview, which also addresses the latest revision of the International Liaison Committee on Resuscitation (ILCOR) guidelines on CPR that resulted in corresponding changes in the European Resuscitation Council (ERC) guidelines.

CPREzy™: an evaluation during simulated cardiac arrest on a hospital bed

CPREzy is a new adjunct designed to improve the application of manual external chest compressions (ECC) during cardiopulmonary resuscitation (CPR). The aim of this study was to determine the effect of using the CPREzy device compared to standard CPR during the simulated resuscitation of a patient on a hospital bed. Twenty medical student volunteers were randomised using a cross over trial design to perform 3 min of continuous ECC using CPREzy and standard CPR. There was a significant improvement in ECC depth with CPREzy compared to standard CPR 42.9 (4.4) mm versus 34.2 (7.6): mm, P = 0.001; 95% CI d.f. 4.4-12.9 mm. This translated to a reduction in the percentage of shallow compressions (<38 mm) with CPREzy 16 (23)% compared to standard CPR 59 (44)%, P = 0.003. There was a small increase in the percentage of compression regarded excessive (>51 mm): CPREzy 6.5 (19)% versus standard CPR 0 (0.1)%. P = 0.012). There was no difference in compression rate or duty cycle between techniques. Equal numbers of participants (40% in each group) performed one of more incorrectly placed chest compression. However the total number of incorrect compressions was higher for the CPREzy group (26% versus 3.9% standard CPR, P < 0.001). This was due to a higher number of low compressions (26% of total compressions for CPREzy versus 1% for standard CPR, P < 0.001). In conclusion, CPREzy was associated with significant improvements in ECC performance. Further animal and clinical studies are required to validate this finding in vivo and to see if it translates to an improvement in outcome in human victims of cardiac arrest.

Birmingham assessment of breathing study (BABS)

BACKGROUND

Current international resuscitation guidelines for lay people rely on the assessment of "normal breathing" as a key sign of breathing and circulation. However, it is not known how accurately laypersons can discriminate between "normal" and "abnormal" breathing. The aim of this study was to test the ability of medical students to discriminate between simulated normal and abnormal breathing patterns and select the correct treatment.

METHODS

Six video clips of simulated breathing were recorded showing: normal; abnormal -shallow, rapid, agonal (obstructed and unobstructed airways); or absent breathing. The clips were validated by three experienced emergency practitioners and then shown in a random order to 48 second-year medical students. For each clip observers were asked to indicate: "Is this patient breathing?" (yes-normal, yes-abnormal, no) and "What action would you take?" (rescue breathing or recovery position).

RESULTS

All experts correctly identified the breathing type and agreed on an appropriate emergency action. Students identified normal breathing as: normal 61%, abnormal 33% and absent 6%; abnormal breathing as: normal 29%, abnormal 61%, absent 10%; and absent breathing as: normal 8%, abnormal 6%, absent 85%. Correct actions were selected in 86% during normal breathing, 51% during abnormal breathing and 86% during absent breathing. The sensitivity for observers correctly identifying normal from abnormal breathing was 60% and specificity 75% and for selecting the correct action was 42% and 80%, respectively.

CONCLUSIONS

Medical students were unable to identify normal breathing from abnormal breathing reliably resulting in a high number of inappropriate, potentially harmful actions. Further evaluation of the optimal method for assessing for signs of breathing and circulation is required.

Arterial blood gases with 700 ml tidal volumes during out-of-hospital CPR

The optimal tidal and minute ventilation during cardiopulmonary resuscitation (CPR) is not known. In the present study seven adult, non-traumatic, out-of-hospital cardiac arrest patients were intubated and mechanically ventilated at 12 min(-1) with 100% oxygen and a tidal volume of 700 ml (10 +/- 2 ml kg(-1)). Arterial blood gas samples were analysed after 6-8 min of unsuccessful resuscitation and mechanical ventilation. Mean PaCO2 was 5.2 +/- 1.3 kPa and mean PaO2 30.7 +/- 17.2 kPa. The patient with the highest (14 ml kg(-1)) and lowest (8 ml kg(-1)) tidal volumes per kg had the lowest and highest PaCO2 values of 2.6 and 6.8 kPa, respectively. Linear regression analysis confirmed a significant correlation between arterial pCO2 and tidal volume in ml/kg, r2 = 0.87. We conclude that aiming for an estimated ventilation of 10 ml kg(-1) tidal volume at frequency of 12 min(-1) might be expected to achieve normocapnia during ALS.

A comparison between over-the-head and standard cardiopulmonary resuscitation

BACKGROUND

Standard cardiopulmonary resuscitation (CPR) is performed by kneeling adjacent to the side of the casualty. In certain circumstances it may be difficult or impossible to perform CPR in this position, for example in confined spaces such as a narrow corridor, aircraft or train gangway. The aim of this study was to investigate the technique of over-the-head CPR (OTH CPR), where the CPR provider kneels above the casualty and performs chest compressions OTH of the casualty.

METHODS

Twenty volunteers were randomised to a cross over trial where they performed standard and OTH CPR at a 7-day interval. Compression and ventilation variables were recorded on the Laerdal Resusci Annie VAM system.

RESULTS

Chest compression depth and ventilation volume declined over time (0-3 min P < 0.001). There was no difference in compression rate, depth, duty cycle or ventilation rate, inflation rate and ventilation volume between techniques. Hand position was incorrect more frequently in the standard compared to the OTH group (incorrect compressions 300 versus 76, respectively, P < 0.001) due principally to a greater proportion of low positioned compressions in the standard CPR group.

CONCLUSION

OTH CPR appears equally effective as standard CPR with some marginal advantages in correct hand placement. We suggest that in situations where it is not possible to perform standard CPR, OTH CPR may be considered as a suitable alternative.

Do different mattresses affect the quality of cardiopulmonary resuscitation?

OBJECTIVE

To determine the effect of different mattresses on cardiopulmonary resuscitation performance and establish whether emergency deflation of an inflatable mattress improves the quality of resuscitation.

DESIGN AND SETTING

Randomised controlled cross-over trial performed in a general ICU PARTICIPANTS: Critical care staff from a general ICU.

INTERVENTIONS

Cardiopulmonary resuscitation on a manikin on the floor or on a bed with a standard foam mattress and inflated and deflated pressure redistributing mattresses. Maximal compression force was measured at different bed heights.

MEASUREMENTS AND RESULTS

Compression depth, duty cycle and rate and percentage correct expired air ventilation were recorded on a manikin. Compression depth was significantly lower on the foam (35.2 mm), inflated (37.2 mm) and deflated mattress (39.1 mm) than the floor (44.2 mm). There were no clinically important differences in duty cycle or compression rate. The quality of ventilation was poor on all surfaces. Maximal compression force declined as bed height increased.

CONCLUSIONS

Resuscitation performance is adversely affected when performed on a bed (irrespective of mattress type) compared to the floor. There were no differences between the inflated and deflated mattresses, although the deflation process did not adversely affect performance. This study does not support the routine deflation of an inflated mattress during resuscitation and questions the potential benefits from using a backboard. The finding that bed height affects maximal compression forces, challenges the recommendation that cardiopulmonary resuscitation be performed with the bed at middle-thigh level and requires further investigation.

Artificial ventilation for basic life support leads to hyperventilation in first aid providers

The 'Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care - International Consensus on Science' recommend an artificial ventilation volume of 10 ml/kg bodyweight (equivalent to a tidal volume of 700-1000 ml) without the use of supplemental oxygen in adults with respiratory arrest. For first aid providers using the mouth-to-mouth or mouth-to-nose-ventilation technique, respectively, a ventilation volume of approximately 9.6 l/min results. Additionally, a deep breath is recommended before each ventilation to increase the end-expiratory oxygen concentration of the air exhaled by the first aid provider. To investigate the effects of these recommendations in healthy volunteers, test persons were asked to ventilate an artificial lung model for a period of up to 10 min. The tidal volume was set at 800 ml at a breathing rate of 12/min. End-tidal carbon dioxide, oxygen saturation (measured by pulse oximetry), and heart rate were measured continuously. Capillary blood gas samples were collected and non-invasive blood pressure readings were recorded prior to the start of ventilation and immediately after the end of the measuring period. The data reveal a statistically significant and clinically relevant decrease in end-tidal carbon dioxide pressure (P<0.001, median decrease 14 mmHg), and the occurrence of hyperventilation-associated symptoms such as paraesthesia, dizziness, and carpopedal spasms in more than 75% of the participants. Clinically and statistically significant hyperventilation results in first aid providers performing artificial ventilation according to the guidelines. This artificial ventilation is associated with a significant decrease in capillary and end-tidal carbon dioxide pressure as well as with multiple symptoms of an acute hyperventilation syndrome. Ventilation performed according to these guidelines may cause injury to the health of the first aid provider. Rescuers ventilating the victim should be replaced at regular intervals and the recommendation to take a deep breath before each ventilation should not be upheld in order to minimise the risk of hyperventilation.

[Automated external defibrillator use during cardiopulmonary resuscitation during flight]

Automated External Defibrillator (AED) during cardiopulmonary resuscitation should reduce mortality rate after out-of-hospital cardiac arrest. We report a case of defibrillation with AED during flight in a patient suffering cardiac arrest complicating an acute myocardial infarction. Two hours before landing, a 56-years-old man presented sudden cardiac arrest. Flight attendants performed basic cardiac life support, including AED. Five shocks were delivered. After landing, acute myocardial infarction was diagnosed and treated by prehospital thrombolysis and angioplasty with favorable outcome. AED is a crucial link of the chain of survival, especially where advance cardiac live support cannot be performed, like during flight. Despite an increasing AED availability, survival after cardiac arrest during flight remains exceptional.

Community competence in cardiopulmonary resuscitation

The aim of this study was to determine community application of cardiopulmonary resuscitation (CPR) skills in an emergency, and, thus, assess the value of training programmes in raising community competence. A cross-sectional telephone survey of the Western Australian population was chosen randomly (n = 803). An urban sub-sample (n = 100) performed a practical demonstration of CPR skills using a simulated collapse scenario using a recording manikin as the victim. Performance was assessed by two observers using pre-determined criteria. Of all respondents, 64% had been trained in CPR. Practical and theoretical assessment scores were significantly better in trained versus untrained participants. The number of times a person was trained in CPR was more effective for retention and competence than time since last trained. Degree of training and theoretical competence were less in those aged over 65 years or with heart disease in the household. Theoretical competence poorly reflected practical performance in many tasks. This study provides a comprehensive database of CPR training and performance, and highlights future directions to ensure appropriate and cost-effective training. Specific factors to be addressed include increasing frequency of training, targeting of high-risk groups, simplification in teaching, and emphasising early activation of the emergency medical system.

Effectiveness of ventilation-compression ratios 1:5 and 2:15 in simulated single rescuer paediatric resuscitation

Current guidelines for paediatric basic life support (BLS) recommend a ventilation-compression ratio of 1:5 during child resuscitation compared with 2:15 for adults, based on the consensus that ventilation is more important in paediatric than in adult BLS. We hypothesized that the ratio 2:15 would provide the same minute ventilation as 1:5 during single-rescuer paediatric BLS due to the reduced time required to change between ventilations and compressions. Fourteen lay rescuers were trained with both ratios and thereafter performed single rescuer BLS for approximately 4 min with each of the two ratios in random order on a child-sized manikin with a built-in respiratory monitor. Quality of chest compressions was assessed by measurement of the rate, depth and position. There were no significant differences in tidal volumes or minute ventilation between the ratios. Nearly all chest compressions were within acceptable limits for depth and place with both methods, but the mean number of chest compressions per minute was 48+/-15% greater with ratio 2:15. In conclusion, there was no difference in ventilation, but nearly one and a half times as many compressions with a ratio of 2:15 than 1:5 for lay rescuers during single rescuer paediatric CPR. In order to simplify CPR training for laypersons, we recommend a 2:15 ratio for both single- and two-person, adult and paediatric layperson BLS.

Automated external defibrillation as part BLS: implications for education and practice

The latest Adult Basic Life Support (BLS) guidelines support the inclusion of the use of the automated external defibrillator (AED), as part of basic life support (BLS). Emphasis on the provision of early defibrillation as part of BLS acknowledges the importance of this manoeuvre in the successful termination of ventricular fibrillation. The ramifications of such changes for both first responders and organisations implementing the guidelines should not be underestimated. Issues relating to resourcing, content and duration of training and retraining, auditing and evaluation require further exploration. To consider these issues now seems particularly pertinent, given the recent launch of the UK Government's paper on public health, 'Saving Lives-Our Healthier Nation' which seeks to deploy AEDs in busy public places for use by trained members of the lay public. Additionally, defibrillation has been identified as one of the key competencies that all trained nurses and other health care providers should be able to undertake. This paper will consider the background to the current guideline changes, analyse the wider implications of translating the recommendations into practice, and offer possible solutions to address the issues raised. Whilst the analysis is particularly pertinent to the United Kingdom, many of the issues raised have international importance.

Prevention of deterioration of ventricular fibrillation by basic life support during out-of-hospital cardiac arrest

Survival of cardiac arrest is improved by basic life support (BLS). This study investigated the relationship between ventricular fibrillation (VF) characteristics and survival. In a 2-year prospective study out-of-hospital witnessed non-traumatic cardiac arrests were observed. The probabilities of recording VF, asystole or other rhythms in relation to BLS and the time to the rhythm recording were analyzed with logistic regression. Amplitude and baseline crossings of VF were related to survival, using linear regression analysis. In 873 patients, the probability to record VF decreased per minute (OR 0.92, 95%CI 0.89-0.95) and of asystole increased (OR 1.13, 95%CI 1.09-1.18) as time from collapse elapsed. BLS reduced these trends significantly for VF (OR 0.97, 95%CI 0.94-0.99) and asystole (OR 1.09, 95%CI 1.05-1.13). This effect was not observed for other rhythms. The amplitude of VF decreased in time; significantly less for patients who received BLS than for those who did not (p=0.009). Survival significantly decreased with lower amplitude of VF (OR 0.23 per mV, 95%CI 0.07-0.79) and with less baseline crossings (OR 0.80 per baseline crossings per second, 95%CI 0.71-0.91). Our study demonstrated that BLS and VF as initial rhythm, considered being "baseline" predictors in survival models, were proved not independent of each other. The decrease of VF amplitude and increase in prevalence of asystole is slowed significantly by BLS. Predicting survival from VF amplitude and baseline crossings alone is limited.

The position of the spine in the recovery position--an experimental comparison between the lateral recovery position and the modified HAINES position

The lateral recovery position is widely used for the positioning of unconscious patients. Ideally, in the setting of trauma it is avoided because of concerns about spinal cord injury. However, unconscious individuals with unsuspected trauma or trauma victims attended by partially trained first-aiders may be placed in the recovery position, potentially endangering the cord. Excessive movement of the spine in the recovery position may increase the risk of spinal cord injury in these situations. A new recovery position, termed the modified HAINES position, is described and the position of the spine in this position is compared with the lateral recovery position.

HYPOTHESIS

That the modified HAINES position results in less distortion of the position of the spine than the lateral recovery position.

METHODS

Thirty-eight healthy volunteers were imaged in the two different positions. Measurements of rotation, flexion and lateral flexion of the cervical and thoraco-lumbar spine were made. Two tailed paired t-tests were employed to compare measurements of the two positions and a McNemar test was used to compare the subjects' subjective experiences.

RESULTS

The modified HAINES position resulted in 13.0 degrees (99% CI: 7.5-18.5) less lateral flexion and 12.6 degrees (99% CI: 9.4-15.9) less extension of the cervical spine while the position of the thoraco-lumbar spine was similar in both positions. Nineteen of 28 subjects found the modified HAINES position more comfortable (not significant).

CONCLUSION

The modified HAINES position results in a more neutral position of the spine making it preferable to the lateral recovery position in the management of patients when trauma may have occurred. Further research is required to ensure that the recovery positions in use today are the best possible.

Trials of teaching methods in basic life support (3): comparison of simulated CPR performance after first training and at 6 months, with a note on the value of re-training

A randomised controlled trial comparing staged teaching of cardiopulmonary resuscitation (CPR) with conventional training provided the additional opportunity to investigate skill acquisition and retention in those attending conventional CPR classes. All subjects were tested immediately after their first instruction period and again at 6-9 months at an unheralded home visit. We were able to assess how far performance was related to poor acquisition of skills and how far it was related to skill decay. Out of 262 subjects who were randomised to receive conventional CPR instruction, 166 were available for home testing at 6-9 months. An invitation to attend for re-training had been accepted by 39 of them. The remaining 127 who attended only a single class comprise the principal study group, with additional comparative observations on the smaller re-trained cohort. Important failings were observed in the acquisition of skills in all modalities tested after the initial instruction. These were particularly marked in skills related to ventilation. Immediately after a class, 68% of trainees performed an effective check of breathing, but only 33% opened the airway as taught and no more than 18% provided an ideal ventilation volume. The technique of chest compression was also less than ideal. Although 80% of subjects placed their hands in an acceptable position, compression to an adequate depth and an adequate rate of compression were achieved by 54 and 63%, respectively. Seventy-eight percent demonstrated a careful approach, and 46% remembered to call for help. A carotid pulse check was simulated by 61% of trainees. When tested 6-9 months later, skill deterioration from this baseline was observed in all modalities tested except for the ventilation volume. The skill decay was significant (P<0.05) for the careful approach, performing an effective breathing check, the carotid pulse check, placing the hands in an acceptable position for chest compression, and compressing at an optimal rate. The minority who attended for re-training showed a trend to protection against skill decay for seven of the ten variables, compared with those who had attended only one training session. This improvement was significant for only two of them, but all were relatively small with limited practical value. Many who attend conventional CPR classes fail to acquire the necessary skills, and the skills that are acquired decline appreciably over the subsequent 6-9 months. The value of conventional re-training was modest in this study of community volunteers.

Evaluation of a new method for the carotid pulse check in cardiopulmonary resuscitation

BACKGROUND

The ability to determine the presence or absence of a central pulse remains a key skill in cardiopulmonary resuscitation (CPR) for healthcare providers, despite studies showing that they perform this poorly. The aim of this study was to evaluate a modified technique for palpation of the carotid pulse.

METHODS

Sixty seven undergraduate dental students were taught the standard method of carotid pulse detection during a basic life support session and were also taught a modified method. Each student was asked to palpate the carotid pulse of a volunteer in two positions (neck neutral and neck extended) with the volunteer on the floor and on a trolley. The time taken to identify the pulse was measured and the scenarios compared.

RESULTS

The time to detect the carotid pulse was reduced in three of the four scenarios (floor, neck extended P=0.0053, trolley neck neutral P=0.0070, trolley neck extended P=0.0024). The final scenario (floor, neck neutral) showed no improvement (P=0.36).

CONCLUSION

The new method of carotid pulse palpation results in a more rapid determination of the carotid pulse when it is present in all positions except with the neck neutral on the floor. This will only be clinically significant if trauma is suspected.

Inspiratory impedance threshold valve during CPR

The use of an inspiratory impedance threshold valve (ITV) during cardiopulmonary resuscitation (CPR) should reduce intrathoracic pressure during natural chest recoil or active chest decompression. This might in turn improve venous return and thereby organ blood flow. The haemodynamic effects during both standard CPR and active compression-decompression (ACD)-CPR with and without the ITV, therefore, were studied in a well-established porcine model with cross-over design. Sixteen pigs were randomised to one of four methods initially, changing the method every fifth minute during mechanical chest compression at 100 min(-1). Myocardial blood flow was doubled when the valve was added to standard CPR, median (q25-q75) 14 (3-47) versus 27 (9-51) ml min(-1) 100 g(-1) (P=0.001). ACD-CPR caused a similar increase, while adding the ITV to ACD-CPR only tended to increase myocardial blood flow (P=0.077). Varying the technique had no effect on cerebral, kidney or carotid blood flow, coronary perfusion pressure, expired CO(2) concentrations or blood gases. The valve is a promising new tool in CPR, but more independent studies of the device are needed.