Short Attention Span Summary
Wait on the ETT
Last month we covered an article showing kids did worse with early intubation during arrest. This study of in-hospital arrest found the same held true in adults. The most important outcome, survival with a good neurological outcome, was better in patients not intubated in the first 15 minutes of arrest. The NNT was 33, the “treatment” being – not intubating them. Overall survival and ROSC were also lower in patients who were intubated. The methods of this huge study were complex. For each minute of arrest, up to 15 minutes, those who were not intubated were propensity matched to those who were and outcomes were calculated. But why did they do worse? Did intubation cause a pause in compressions or delay in other aspects of resuscitation? Did intubated patients get overzealous bagging with breath stacking? It is hard to know. Of course, this was observational and subject to confounding despite propensity matching.
Spoon Feed
Early intubation in adult in-hospital arrest was associated with poorer outcomes and worse neurologically-intact survival. Emphasize high quality CPR and defibrillation, while deemphasizing early ETT placement.
Abstract
JAMA. 2017 Jan 24. doi: 10.1001/jama.2016.20165. [Epub ahead of print]
Association Between Tracheal Intubation During Adult In-Hospital Cardiac Arrest and Survival.
Andersen LW1, Granfeldt A2, Callaway CW3, Bradley SM4, Soar J5, Nolan JP6, Kurth T7, Donnino MW8; American Heart Association’s Get With The Guidelines–Resuscitation Investigators.
Author information:
1Research Center for Emergency Medicine, Aarhus University Hospital, Aarhus, Denmark2Department of Anesthesiology, Aarhus University Hospital, Aarhus, Denmark3Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
2Department of Anesthesiology, Aarhus University Hospital, Aarhus, Denmark.
3Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
4Division of Cardiology, Department of Medicine, VA Eastern Colorado Health Care System, Denver6Now with Minneapolis Heart Institute, Minneapolis, Minnesota.
5Anaesthesia and Intensive Care Medicine, Southmead Hospital, Bristol, England.
6University of Bristol, Bristol, England9Department of Anaesthesia and Intensive Care Medicine, Royal United Hospital, Bath, England.
7Institute of Public Health, Charité-Universitätsmedizin Berlin, Berlin, Germany.
8Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts11Division of Pulmonary and Critical Care Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
Abstract
Importance:
Tracheal intubation is common during adult in-hospital cardiac arrest, but little is known about the association between tracheal intubation and survival in this setting.
Objective:
To determine whether tracheal intubation during adult in-hospital cardiac arrest is associated with survival to hospital discharge.
Design, Setting, and Participants:
Observational cohort study of adult patients who had an in-hospital cardiac arrest from January 2000 through December 2014 included in the Get With The Guidelines-Resuscitation registry, a US-based multicenter registry of in-hospital cardiac arrest. Patients who had an invasive airway in place at the time of cardiac arrest were excluded. Patients intubated at any given minute (from 0-15 minutes) were matched with patients at risk of being intubated within the same minute (ie, still receiving resuscitation) based on a time-dependent propensity score calculated from multiple patient, event, and hospital characteristics.
Exposure:
Tracheal intubation during cardiac arrest.
Main Outcomes and Measures:
The primary outcome was survival to hospital discharge. Secondary outcomes included return of spontaneous circulation (ROSC) and a good functional outcome. A cerebral performance category score of 1 (mild or no neurological deficit) or 2 (moderate cerebral disability) was considered a good functional outcome.
Results:
The propensity-matched cohort was selected from 108 079 adult patients at 668 hospitals. The median age was 69 years (interquartile range, 58-79 years), 45 073 patients (42%) were female, and 24 256 patients (22.4%) survived to hospital discharge. Of 71 615 patients (66.3%) who were intubated within the first 15 minutes, 43 314 (60.5%) were matched to a patient not intubated in the same minute. Survival was lower among patients who were intubated compared with those not intubated: 7052 of 43 314 (16.3%) vs 8407 of 43 314 (19.4%), respectively (risk ratio [RR] = 0.84; 95% CI, 0.81-0.87; P < .001). The proportion of patients with ROSC was lower among intubated patients than those not intubated: 25 022 of 43 311 (57.8%) vs 25 685 of 43 310 (59.3%), respectively (RR = 0.97; 95% CI, 0.96-0.99; P < .001). Good functional outcome was also lower among intubated patients than those not intubated: 4439 of 41 868 (10.6%) vs 5672 of 41 733 (13.6%), respectively (RR = 0.78; 95% CI, 0.75-0.81; P < .001). Although differences existed in prespecified subgroup analyses, intubation was not associated with improved outcomes in any subgroup.
Conclusions and Relevance:
Among adult patients with in-hospital cardiac arrest, initiation of tracheal intubation within any given minute during the first 15 minutes of resuscitation, compared with no intubation during that minute, was associated with decreased survival to hospital discharge. Although the study design does not eliminate the potential for confounding by indication, these findings do not support early tracheal intubation for adult in-hospital cardiac arrest.
PMID: 28118660 [PubMed – as supplied by publisher]
We have read with great interest the study by Andersen et al. [1]. In this study, patients who were intubated during resuscitation were significantly less likely to survive to discharge than those who were not (16% vs. 19%) and were less likely to be discharged with good functional status. Despite its well described strengths/limitations, the scientific community cannot rely on a single study and suggest that intubation should be de-emphasized during cardiopulmonary resuscitation (CPR).
Although research has provided important insights into the physiology of cardiac arrest and CPR, our understanding of the interaction between chest compression and mechanical ventilation is limited. As we all know, both ‘cardiac pump’ and ‘thoracic pump’ may have a role in forward blood flow during CPR and it would not be so wise to deprive the favorable effects of the latter from our patients. Of course, positive intrathoracic pressure may be harmful if excessive and proper timing of compression and ventilation may actually be the key for improving the circulation [2]. In fact, positive pressure ventilation may have additional effects, such as pulmonary recruitment, minimal thoracic volume reduction, reduced ventilation/perfusion mismatch, and improved oxygenation [3-6].
Our research group found an association between mean airway pressure and outcome of CPR in mechanically ventilated patients, with a value of 42.5 mbar being associated with ROSC [7]. Although strict inclusion criteria were used in this study, our findings clearly indicate that the effect of thoracic pump cannot be de-emphasized or ignored. In patients with preserved physiology, i.e. those who immediately receive bystander CPR, the use of an automated ventilator may allow for the optimal exploitation of positive intrathoracic pressure while avoiding excessive ventilation volume and rate and eliminating gastric inflation, which are common when ventilating with a self-inflating bag. Patients with preserved physiology are those in whom ischemic contracture and relaxation of the airway smooth muscles have not yet ensued, allowing for the full exploitation of both pumps.
Moreover, as all patients with ROSC are admitted to the ICU, we cannot anticipate what complications are going to arise, such as sepsis, VILI, etc., which may influence survival rates. Therefore, prognosis involves consideration of many parameters, and cannot be easily associated with intubation. This could be possible in intubated patients who are ventilated with a self-inflating bag and excessive tidal volumes.
Further research and search for new strategies are necessary in a field where survival rates still need to improve. New approaches to CPR should focus on improving perfusion by ventilation patterns associated with the effects of chest compressions instead of de-emphasizing intubation.
References
1. Andersen LW, Granfeldt A, Callaway CW, et al; American Heart Association’s Get With The Guidelines–Resuscitation Investigators. Association Between Tracheal Intubation During Adult In-Hospital Cardiac Arrest and Survival. JAMA 2017;317:494-506.
2. Chalkias A, Xanthos T. Timing positive-pressure ventilation during chest compression: the key to improving the thoracic pump? Eur Heart J Acute Cardiovasc Care 2015;4:24-7.
3. Idris AH, Banner MJ, Wenzel V, et al. Ventilation caused by external chest compression is unable to sustain effective gas exchange during CPR: a comparison with mechanical ventilation. Resuscitation 1994;28:143-50.
4. Markstaller K, Karmrodt J, Doebrich M, et al. Dynamic computed tomography: a novel technique to study lung aeration and atelectasis formation during experimental CPR. Resuscitation 2002;53:307-13.
5. Cordioli RL, Lyazidi A, Rey N, et al. Impact of ventilation strategies during chest compression: an experimental study with clinical observations. J Appl Physiol (1985) 2016;120:196-203.
6. Kill C, Galbas M, Neuhaus C, et al. Chest compression synchronized ventilation versus intermitted positive pressure ventilation during cardiopulmonary resuscitation in a pig model. PLoS One 2015;10:e0127759.
7. Chalkias A, Pavlopoulos F, Koutsovasilis A, et al. Airway pressure and outcome of out-of-hospital cardiac arrest: A prospective observational study. Resuscitation. 2017;110:101-6.