We thank Dr Patel et al. for their interest in our article entitled “Prognostic value of signs of life throughout cardiopulmonary resuscitation for refractory out-of-hospital cardiac arrest”, recently published in Resuscitation.
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We would like to bring some additional insights regarding the issues they raised in their letter.First, Patel et al. question the consistency of advanced life support (ALS) guidelines over the recruitment period, which spanned from 2009 to 2017 across the three primary cohort studies. Actually, French guidelines for extracorporeal cardiopulmonary resuscitation (ECPR) did not changed over the study period.
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Although compliance with current ALS guidelines was advocated, physicians on scene could adjust therapies according to individual characteristics or local clinical practices in these observational studies.Second, Patel et al. might have misunderstood the patterns of missing values for any sign of life in our study. Basically, this variable was a composite of gasping, pupillary light reaction, and increased level of consciousness. Any sign of life was missing if any component yielded missing value while the other were coded as « no ». As shown in Table 1, there were seven patterns, totaling 54 individuals, with missing values for any sign of life (i.e., pattern 3, 7, 9, 19, 21, 25, 27). Hence, the denominator for computing the prevalence of any sign of life was 380 (i.e., 434–54).
Table 1Patterns of missing values for any sign of life (n = 434).
| Pattern | Gasping | Pupillary light reaction | Increased level of consciousness | Any sign of life | No. individuals |
|---|---|---|---|---|---|
| 1 | No | No | No | No | 150 |
| 2 | No | No | Yes | Yes | 0 |
| 3 | No | No | Missing | Missing | 0 |
| 4 | No | Yes | No | Yes | 68 |
| 5 | No | Yes | Yes | Yes | 10 |
| 6 | No | Yes | Missing | Yes | 4 |
| 7 | No | Missing | No | Missing | 4 |
| 8 | No | Missing | Yes | Yes | 11 |
| 9 | No | Missing | Missing | Missing | 48 |
| 10 | Yes | No | No | Yes | 12 |
| 11 | Yes | No | Yes | Yes | 1 |
| 12 | Yes | No | Missing | Yes | 3 |
| 13 | Yes | Yes | No | Yes | 51 |
| 14 | Yes | Yes | Yes | Yes | 20 |
| 15 | Yes | Yes | Missing | Yes | 1 |
| 16 | Yes | Missing | No | Yes | 39 |
| 17 | Yes | Missing | Yes | Yes | 7 |
| 18 | Yes | Missing | Missing | Yes | 2 |
| 19 | Missing | No | No | Missing | 2 |
| 20 | Missing | No | Yes | Yes | 0 |
| 21 | Missing | No | Missing | Missing | 0 |
| 22 | Missing | Yes | No | Yes | 1 |
| 23 | Missing | Yes | Yes | Yes | 0 |
| 24 | Missing | Yes | Missing | Yes | 0 |
| 25 | Missing | Missing | No | Missing | 0 |
| 26 | Missing | Missing | Yes | Yes | 0 |
| 27 | Missing | Missing | Missing | Missing | 0 |
| Missing values, n | 3 | 111 | 58 | 54 | … |
| Denominator, n | 431 | 323 | 376 | 380 | … |
The intention-to-treat approach is relevant for randomized controlled trials but may not be suitable for observational studies. Indeed, the occurrence of signs of life was not based on random assignment in our observational study and its prognostic significance is unlikely to be studied by randomized controlled trials. Yet, we performed multiple imputations of missing values in order to circumvent the problem of missing data.
Third, we concur with Patel et al. that ECPR might benefit a limited number of patients. Because the receipt of ECPR was an inclusion criterion across the three primary studies, we could not determine accurately which percentages of OHCA individuals experienced refractory cardiac arrest and showed signs of life throughout cardiopulmonary resuscitation. Importantly, outcomes for ECPR recipients with refractory cardiac arrest relate with many factors including initial cardiac rhythm, cardiopulmonary resuscitation quality, delay in ECPR implementation, ischia-reperfusions injuries and signs of life.
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Cost-effectiveness analysis of ECPR need to account for the fact that most patients are young (mean 49 ± 13 years) and 63/69 (91%) survive with favorable neurologic function. Consistently, most recent guidelines consider ECPR as a rescue therapy for selected patients with cardiac arrest when conventional ALS measures are failing or in order to facilitate specific interventions.5
Conflict of interest
None of the other authors have any financial conflict of interest to disclose.
References
- Prognostic value of signs of life throughout cardiopulmonary resuscitation for refractory out-of-hospital cardiac arrest.Resuscitation. 2021; 162: 163-170
- Guidelines for indications for the use of extracorporeal life support in refractory cardiac arrest. French Ministry of Health.Ann Fr Anesth Reanim. 2009; 28: 182-190
- Prognostic factors for extracorporeal cardiopulmonary resuscitation recipients following out-of-hospital refractory cardiac arrest. A systematic review and meta-analysis.Resuscitation. 2017; 112: 1-10
- Advanced reperfusion strategies for patients with out-of-hospital cardiac arrest and refractory ventricular fibrillation (ARREST): a phase 2, single centre, open-label, randomised controlled trial.Lancet. 2020; 396: 1807-1816
- European Resuscitation Council guidelines 2021: adult advanced life support.Resuscitation. 2021; 161: 115-151
Article info
Publication history
Published online: May 04, 2021
Received:
April 7,
2021
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© 2021 Elsevier B.V. All rights reserved.
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- Prognostic value of signs of life in refractory out-of-hospital cardiac arrestResuscitationVol. 164
- PreviewWe read the recent article entitled “Prognostic value of signs of life throughout cardiopulmonary resuscitation for refractory out-of-hospital cardiac arrest” authored by Debaty et al.1 We applaud the authors' work for prognostication of refractory out-of-hospital cardiac arrest (OHCA), as it certainly adds valuable information to the current literature. After reviewing the article, we have some comments to share with you.
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