Prognostication after cardiac arrest: Time to change our approach

ED prognostication of comatose cardiac arrest patients undergoing therapeutic hypothermia is unreliable

BACKGROUND

Therapeutic hypothermia (TH) improves patient survival with good neurologic outcome after cardiac arrest. The value of early clinician prognostication in the emergency department (ED) has not been studied in this patient population.

OBJECTIVE

To determine if physicians can accurately predict survival and neurologic outcome at hospital discharge of resuscitated, comatose out-of-hospital cardiac arrest (OHCA) patients treated in a post-cardiac arrest clinical pathway that included TH.

METHODS

This was a prospective, observational study conducted at a tertiary referral center. Participants were physicians involved in the resuscitation of OHCA patients treated with a clinical pathway that included TH. Immediately after patient resuscitation in the ED, physicians recorded their prediction of patient survival and neurologic outcome on a standardized questionnaire. Neurologic outcome was assessed by the cerebral performance category.

RESULTS

Forty-two physicians completed questionnaires on 17 patients enrolled from October 2009 to March 2010. Sensitivity and specificity of physician prediction of patient survival were 0.67 (95% confidence interval [CI], 0.45-0.83) and 0.82 (95% CI, 0.59-0.94), respectively, with an area under the curve of 0.74 (95% CI, 0.61-0.88), a positive likelihood ratio (+LR) of 3.72 (95% CI, 1.30-11.02), and a -LR of 0.40 (95% CI, 0.21-0.77). Sensitivity and specificity of physician prediction of good neurologic outcome were 0.40 (95% CI, 0.20-0.64) and 0.69 (95% CI, 0.50-0.84), respectively, with an area under the curve of 0.55 (95% CI, 0.39-0.70), a +LR of 1.29 (95% CI, 0.56-3.03), and a -LR of 0.87 (95% CI, 0.53-1.41).

CONCLUSIONS

Physicians poorly prognosticate both survival and neurologic outcome in comatose OHCA patients undergoing TH. Premature prognostication in the ED is unreliable and should be avoided.

[Prognostic assessment as the basis for limiting therapy in unconscious patients after cardiopulmonary resuscitation]

BACKGROUND

The prognosis of patients who have been resuscitated after cardiac arrest is still unfavourable and long-term results have only slightly improved. As a consequence, intensivists are frequently confronted with the question of limiting active therapeutic efforts for patients in prolonged coma. The history of the patient and circumstances of the resuscitation are of limited value with regard to reliable decisions.

THERAPEUTIC DECISION-MAKING

Clinical and electrophysiological neurologic techniques as well as biomarkers and diagnostic imaging are, therefore, the basis for prognostication and potential consecutive therapeutic decisions. Sedation, relaxation and particularly therapeutic hypothermia have great influence on the test results. These influences have to be excluded before results can be validated. With regard to therapeutic hypothermia a reliable neurologic evaluation as a basis for limiting treatment is only possible after rewarming. Moreover results of multiple tests should be in agreement before a decision to limit treatment can be made. Finally it must be kept in mind that the absence of unfavourable test results is not proof of a good prognosis.

CONCLUSION

The decision to limit treatment can not be made on the basis of a single adverse prognostic sign, but requires a comprehensive clinical diagnostic assessment.

Prognostic value of electrographic postanoxic status epilepticus in comatose cardiac-arrest survivors in the therapeutic hypothermia era

BACKGROUND

The independent prognostic significance of postanoxic status epilepticus (PSE) has not been evaluated prospectively since the introduction of therapeutic hypothermia. We studied 1-year functional outcomes and their determinants in comatose survivors of cardiac arrest (CA), with special attention to PSE.

METHODS

106 comatose CA survivors admitted to the intensive care unit in 2005-2010 were included in a prospective observational study. The main outcome measure was a Cerebral Performance Category scale (CPC) of 1 or 2 (favorable outcome) 1 year after CA.

RESULTS

CA occurred out-of-hospital in 89 (84%) patients and was witnessed from onset in 94 (89%). Median times were 6 min (IQR, 0-11) from CA to first-responder arrival and 23 min (14-40) from collapse to return of spontaneous circulation. PSE was diagnosed in 33 (31%) patients at a median of 39 h (4-49) after CA. PSE was refractory in 24 (22%) cases and malignant in 19 (20%). After 1 year, 31 (29.3%) patients had favorable outcomes including 2 (6.44%) with PSE. Factors independently associated with poor outcome (CPC ≥ 3) were PSE (odds ratio [OR], 14.28; 95% confidence interval [95% CI], 2.77-50.0; P=0.001), time to restoration of spontaneous circulation (OR, 1.04/min; 95% CI, 1-1.07; P=0.035), and LOD score on day 1 (OR, 1.28/point; 95% CI, 1.08-1.54; P=0.003).

CONCLUSION

PSE strongly and independently predicts a poor outcome in comatose CA survivors receiving therapeutic hypothermia, but some patients with PSE survive with good functional outcomes. PSE alone is not sufficient to predict failure to awaken after CA in the era of therapeutic hypothermia.