Anderson LW, Granfeldt A, Callaway CW et al.
JAMA. 2017;317(5):494-506. DOI:10.1001/jama.2016.20165
AIM OF STUDY
Is tracheal intubation during in-hospital cardiac arrest associated with survival to hospital discharge?
Retrospective, observational cohort-study
Data collected from January 2000 to December 2014 from a US-based multi-centre prospective registry of in-hospital cardiac arrest
Patients populated in to two groups, those undergoing endotracheal intubation within fifteen minutes and those not.
Patients were then 1:1 matched with patients at risk of being intubated within the same minute 1:1 using a propensity score with nearest neighbour-matching algorithm
Propensity score based on Cox Proportional Hazard Score which calculated risk of needing intubation at any given minute according to multiple covariates.
Survival to discharge
ROSC, meaningful neurological recovery (1 or 2 on Utstein scale)
Independent categorical variables were compared with the χ2 test, and the Cochran-Armitage test was used to test for trends in tracheal intubation over time.
Time-Dependent Propensity Score–Matched Analysis
Sensitivity analysis to evaluate effect of missing data
Risk ratios with 95%confidence intervals for predefined subgroup analyses
Survival to hospital discharge significantly lower in intubation group (p<0.001)
33.2% NO TUBE vs. 17% TUBE, risk ratio (RR) 0.58 (95% C.I. 0.57-0.59)
Propensity Score-Matched Analysis (p<0.001) 19.4% vs. 16.3%, RR 0.84 (95% C.I. 0.81-0.87)
Return of spontaneous circulation significantly lower in intubation group (p<0.001)
69% vs. 59.2%, RR 0.75 (95% C.I. 0.73-0.76)
Propensity Score-Matched Analysis (p<0.001) 59.3% vs. 57.8%, RR 0.97 (95% C.I. 0.96-0.99)
Favourable functional outcome at discharge significantly lower in intubation group (p<0.001) 25.7% vs. 11.2%, RR 0.55 (95% C.I. 0.54-0.56)
Propensity Score-Matched Analysis (p<0.001) 13.6% vs. 10.6%, RR 0.78 (95% C.I. 0.75-0.81)
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.
STATED LIMITATIONS FROM STUDY
Unsuccessful intubations not recorded
Time taken to intubate, which is likely to be a large confounding factor in outcome.
Patients who are intubated might be more sick, despite efforts, residual bias may exist
Intubation may result in hyperoxia which can be associated with harm.
Practices in resuscitation have changed over the 15 years of data collection
Control patients are individuals who were not intubated during the same minute Vs intubated. However, these controls may be intubated in subsequent minutes. In the propensity matched groups, a number of patients that were intubated within 15 minutes were included in the no intubation group. These patients could have also been included in the intubation group.
Baseline difference – significantly more patients with VF/VT and witnessed arrest in no intubation group; and significantly lower use of adrenaline
Due to the difficulty of collecting accurate data during a cardiac arrest there is the possibility of timings being misclassified
DISCUSSION FROM JOURNAL CLUB MEETING
Raised questions and discussion surrounding current practice
Emphasis on time taken for intubation
Importance of minimizing delays to other interventions, such as cardioversion, adrenaline and CPR
Summary by Dr W Turner. Journal Club 28 September 2017.