G Model RESUS-5979; No. of Pages 2
ARTICLE IN PRESS Resuscitation xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
Editorial
Keep your hands on the chest
Current guidelines in life support advise to maximise the amount of time that rescuers perform chest compressions.1 There is evidence that increasing the chest compression fraction (hands on time) improves outcome when comparing low fractions to high fractions, however, there is not much in the way of evidence for better outcomes when the fraction of chest compressions is already quite high. Should we be going further to improve fraction of hands on time if we are already providing good CPR with a high compression fraction? This is an important question given the current guidelines and also the push in some quarters to go to “hands on” defibrillation (continuing to do CPR whilst a shock is delivered). Whilst current research would suggest that this is likely to be safe for rescuers,2,3 it is contrary to all current training in DC cardioversion, and there are some concerns about it,5 even when wearing gloves.4 Checking that there is no contact with the patient prior to delivering a shock is insisted upon during all ALS training, and not doing so would result in failure to pass any course teaching it. This requirement reduces the amount of time compressions can be performed for. Because this is so ingrained in the culture of resuscitation, to achieve a change in practice would require robust evidence not only of safety but also efficacy (Should rescuers be asked to perform a task that they have previously been told is dangerous, unless there is very good evidence it is of benefit to the patient?). Studies have previously looked at safety and the electrical current passing through rescuers when performing hands on defibrillation, and these are encouraging.2 However, the evidence that it would make a difference to outcomes is somewhat lacking in the case of good quality, high compression fraction CPR, with one study suggesting that increasing the fraction above a certain threshold does not result in any outcome benefit. Rea et al.6 have looked at the effect of chest compression fraction on Return of Spontaneous Circulation (ROSC), survival to discharge from hospital and favourable neurological outcome on hospital discharge in patients presenting with out of hospital ventricular fibrillation (VF). The patients were included from a 4 year period. Those having less than 5 min of CPR were excluded, as were those who had had shocks from public access defibrillators, those in whom no measurements of CPR were available, and those who had a mechanical device providing CPR as part of a trial. The patient groups were subdivided into those having between 5 and 10 min CPR, those having between 10 and 20 min CPR and those having greater than 20 min CPR. Chest compression fraction was determined by review of electronic recordings of ECG machines/defibrillators and audio recordings. The results show that for those requiring long periods (greater than 20 min) of CPR, a
higher chest compression fraction resulted in a greater proportion of patients achieving ROSC, survival to hospital discharge and favourable neurological outcomes. This is in a group of patients whose cut point for high and low CPR fractions is in the 80% region. The “low fraction” group in this study has a high fraction compared to previous studies.7 The patients in the longer duration subgroups were included in the shorter duration groups (i.e. those analysed as having 10–20 min CPR were included in the 5–10 min group and those in the greater than 20 min group were in the other 2 groups as well). This is important in improving the external validity of the study, as we do not know when we start CPR how long it is going to last, nor whether it will be successful. The odds ratios for these outcomes in the longer duration subgroup do, however, have wide confidence intervals, which implies that the numbers of patients and events was relatively small, and that more work is needed to improve the accuracy of this result. Additionally, the lower 95% confidence intervals appear very near 1 (the no effect line), so whilst these results are statistically significant in this study, it would not take much contrary data in a meta-analysis to bring the confidence intervals of the odds ratios over the no effect limit. The exclusion of those with mechanical devices providing CPR is necessary in this study as it states they were part of other trials. But, the use of such devices may increase the fraction of chest compressions, in that interruption of compressions with these devices is with turning a dial or switch, and then turning it back on, and potentially allow for ongoing compressions with defibrillation. Unlike human rescuers, they do not tire, and do not have to swap over with other rescuers, allowing for continuous CPR. However, a recent large study with approximately 1300 patients in each arm showed no benefit of mechanical devices over manual CPR.8 In summary, this paper gives us some evidence that the current guidelines on minimising disruption of CPR are correct, and that during resuscitation we should be encouraging CPR to continue as much as possible. This does not, however, provide the rigorous evidence we need to encourage the study of hands on defibrillation. Conflict of interest statement There are no declared conflicts of interest. References 1. Hazinski MF, Nolan JP, Billi JE, et al. Part 1: Executive summary: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular
http://dx.doi.org/10.1016/j.resuscitation.2014.04.019 0300-9572/© 2014 Elsevier Ireland Ltd. All rights reserved.
Please cite this article in press as: Haig http://dx.doi.org/10.1016/j.resuscitation.2014.04.019
S.
Keep
your
hands
on
the
chest.
Resuscitation
(2014),
G Model RESUS-5979; No. of Pages 2 2
2.
3.
4.
5. 6.
ARTICLE IN PRESS Editorial / Resuscitation xxx (2014) xxx–xxx
Care Science with Treatment Recommendations. Circulation 2010;122: 50–75. Lloyd MS, Heeke B, Walter PF, Langberg JJ. Hands-on defibrillation. An analysis of electrical current flow through rescuers in direct contact with patients during biphasic external defibrillation. Circulation 2008;117: 2510–4. Neumann T, Gruenewald M, Lauenstein C, Drews T, Iden T, Meybohm P. Handson defibrillation has the potential to improve the quality of cardiopulmonary resuscitation and is safe for rescuers—a preclinical study. J Am Heart Assoc 2012;1:e001313. Sullivan JL, Chapman FW. Will medical examination gloves protect rescuers from defibrillation voltages during hands-on defibrillation? Resuscitation 2012;83:1467–72. Weingart SD. A note of caution on the performance of hands-on biphasic defibrillation. Resuscitation 2013;84:e53. Rea T, Olsufka M, Yin L, Maynard C, Cobb L. The relationship between chest compression fraction and outcome from ventricular fibrillation arrests in prolonged resuscitations. Resuscitation 2014.
Please cite this article in press as: Haig http://dx.doi.org/10.1016/j.resuscitation.2014.04.019
S.
7. Christenson J, Andrusiek D, Everson-Stewart S, et al. Chest compression fraction determines survival in patients with out-of-hospital ventricular fibrillation. Circulation 2009;120:1241–7. 8. Rubertsson S, Lindgren E, Smekal D, et al. Mechanical chest compressions and simultaneous defibrillation vs conventional cardiopulmonary resuscitation in out-of-hospital cardiac arrest. The LINC randomized trial. JAMA 2014;311:53–61.
Keep
Stephen Haig Emergency Department, Great Western Hospital, Marlborough Road, Swindon SN3 6BB, United Kingdom E-mail addresses: [email protected], [email protected], [email protected]. 11 April 2014
your
hands
on
the
chest.
Resuscitation
(2014),
ARTICLE IN PRESS Resuscitation xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
Editorial
Keep your hands on the chest
Current guidelines in life support advise to maximise the amount of time that rescuers perform chest compressions.1 There is evidence that increasing the chest compression fraction (hands on time) improves outcome when comparing low fractions to high fractions, however, there is not much in the way of evidence for better outcomes when the fraction of chest compressions is already quite high. Should we be going further to improve fraction of hands on time if we are already providing good CPR with a high compression fraction? This is an important question given the current guidelines and also the push in some quarters to go to “hands on” defibrillation (continuing to do CPR whilst a shock is delivered). Whilst current research would suggest that this is likely to be safe for rescuers,2,3 it is contrary to all current training in DC cardioversion, and there are some concerns about it,5 even when wearing gloves.4 Checking that there is no contact with the patient prior to delivering a shock is insisted upon during all ALS training, and not doing so would result in failure to pass any course teaching it. This requirement reduces the amount of time compressions can be performed for. Because this is so ingrained in the culture of resuscitation, to achieve a change in practice would require robust evidence not only of safety but also efficacy (Should rescuers be asked to perform a task that they have previously been told is dangerous, unless there is very good evidence it is of benefit to the patient?). Studies have previously looked at safety and the electrical current passing through rescuers when performing hands on defibrillation, and these are encouraging.2 However, the evidence that it would make a difference to outcomes is somewhat lacking in the case of good quality, high compression fraction CPR, with one study suggesting that increasing the fraction above a certain threshold does not result in any outcome benefit. Rea et al.6 have looked at the effect of chest compression fraction on Return of Spontaneous Circulation (ROSC), survival to discharge from hospital and favourable neurological outcome on hospital discharge in patients presenting with out of hospital ventricular fibrillation (VF). The patients were included from a 4 year period. Those having less than 5 min of CPR were excluded, as were those who had had shocks from public access defibrillators, those in whom no measurements of CPR were available, and those who had a mechanical device providing CPR as part of a trial. The patient groups were subdivided into those having between 5 and 10 min CPR, those having between 10 and 20 min CPR and those having greater than 20 min CPR. Chest compression fraction was determined by review of electronic recordings of ECG machines/defibrillators and audio recordings. The results show that for those requiring long periods (greater than 20 min) of CPR, a
higher chest compression fraction resulted in a greater proportion of patients achieving ROSC, survival to hospital discharge and favourable neurological outcomes. This is in a group of patients whose cut point for high and low CPR fractions is in the 80% region. The “low fraction” group in this study has a high fraction compared to previous studies.7 The patients in the longer duration subgroups were included in the shorter duration groups (i.e. those analysed as having 10–20 min CPR were included in the 5–10 min group and those in the greater than 20 min group were in the other 2 groups as well). This is important in improving the external validity of the study, as we do not know when we start CPR how long it is going to last, nor whether it will be successful. The odds ratios for these outcomes in the longer duration subgroup do, however, have wide confidence intervals, which implies that the numbers of patients and events was relatively small, and that more work is needed to improve the accuracy of this result. Additionally, the lower 95% confidence intervals appear very near 1 (the no effect line), so whilst these results are statistically significant in this study, it would not take much contrary data in a meta-analysis to bring the confidence intervals of the odds ratios over the no effect limit. The exclusion of those with mechanical devices providing CPR is necessary in this study as it states they were part of other trials. But, the use of such devices may increase the fraction of chest compressions, in that interruption of compressions with these devices is with turning a dial or switch, and then turning it back on, and potentially allow for ongoing compressions with defibrillation. Unlike human rescuers, they do not tire, and do not have to swap over with other rescuers, allowing for continuous CPR. However, a recent large study with approximately 1300 patients in each arm showed no benefit of mechanical devices over manual CPR.8 In summary, this paper gives us some evidence that the current guidelines on minimising disruption of CPR are correct, and that during resuscitation we should be encouraging CPR to continue as much as possible. This does not, however, provide the rigorous evidence we need to encourage the study of hands on defibrillation. Conflict of interest statement There are no declared conflicts of interest. References 1. Hazinski MF, Nolan JP, Billi JE, et al. Part 1: Executive summary: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular
http://dx.doi.org/10.1016/j.resuscitation.2014.04.019 0300-9572/© 2014 Elsevier Ireland Ltd. All rights reserved.
Please cite this article in press as: Haig http://dx.doi.org/10.1016/j.resuscitation.2014.04.019
S.
Keep
your
hands
on
the
chest.
Resuscitation
(2014),
G Model RESUS-5979; No. of Pages 2 2
2.
3.
4.
5. 6.
ARTICLE IN PRESS Editorial / Resuscitation xxx (2014) xxx–xxx
Care Science with Treatment Recommendations. Circulation 2010;122: 50–75. Lloyd MS, Heeke B, Walter PF, Langberg JJ. Hands-on defibrillation. An analysis of electrical current flow through rescuers in direct contact with patients during biphasic external defibrillation. Circulation 2008;117: 2510–4. Neumann T, Gruenewald M, Lauenstein C, Drews T, Iden T, Meybohm P. Handson defibrillation has the potential to improve the quality of cardiopulmonary resuscitation and is safe for rescuers—a preclinical study. J Am Heart Assoc 2012;1:e001313. Sullivan JL, Chapman FW. Will medical examination gloves protect rescuers from defibrillation voltages during hands-on defibrillation? Resuscitation 2012;83:1467–72. Weingart SD. A note of caution on the performance of hands-on biphasic defibrillation. Resuscitation 2013;84:e53. Rea T, Olsufka M, Yin L, Maynard C, Cobb L. The relationship between chest compression fraction and outcome from ventricular fibrillation arrests in prolonged resuscitations. Resuscitation 2014.
Please cite this article in press as: Haig http://dx.doi.org/10.1016/j.resuscitation.2014.04.019
S.
7. Christenson J, Andrusiek D, Everson-Stewart S, et al. Chest compression fraction determines survival in patients with out-of-hospital ventricular fibrillation. Circulation 2009;120:1241–7. 8. Rubertsson S, Lindgren E, Smekal D, et al. Mechanical chest compressions and simultaneous defibrillation vs conventional cardiopulmonary resuscitation in out-of-hospital cardiac arrest. The LINC randomized trial. JAMA 2014;311:53–61.
Keep
Stephen Haig Emergency Department, Great Western Hospital, Marlborough Road, Swindon SN3 6BB, United Kingdom E-mail addresses: [email protected], [email protected], [email protected]. 11 April 2014
your
hands
on
the
chest.
Resuscitation
(2014),
