Mild Hypercapnia or Normocapnia after Out-of-Hospital Cardiac Arrest

• Abstract Background Guidelines recommend normocapnia for adults with coma who are resuscitated after out-of-hospital cardiac arrest. However, mild hypercapnia increases cerebral blood flow and may improve neurologic outcomes. Methods We randomly assigned adults with coma who had been resuscitated after out-of-hospital cardiac arrest of presumed cardiac or unknown cause and admitted to the intensive care unit (ICU) in a 1:1 ratio to either 24 hours of mild hypercapnia (target partial pressure of arterial carbon dioxide [Paco2], 50 to 55 mm Hg) or normocapnia (target Paco2, 35 to 45 mm Hg). The primary outcome was a favorable neurologic outcome, defined as a score of 5 (indicating lower moderate disability) or higher, as assessed with the use of the Glasgow Outcome Scale-Extended (range, 1 [death] to 8, with higher scores indicating better neurologic outcome) at 6 months. Secondary outcomes included death within 6 months. Results A total of 1700 patients from 63 ICUs in 17 countries were recruited, with 847 patients assigned to targeted mild hypercapnia and 853 to targeted normocapnia. A favorable neurologic outcome at 6 months occurred in 332 of 764 patients (43.5%) in the mild hypercapnia group and in 350 of 784 (44.6%) in the normocapnia group (relative risk, 0.98; 95% confidence interval [CI], 0.87 to 1.11; P=0.76). Death within 6 months after randomization occurred in 393 of 816 patients (48.2%) in the mild hypercapnia group and in 382 of 832 (45.9%) in the normocapnia group (relative risk, 1.05; 95% CI, 0.94 to 1.16). The incidence of adverse events did not differ significantly between groups. Conclusions In patients with coma who were resuscitated after out-of-hospital cardiac arrest, targeted mild hypercapnia did not lead to better neurologic outcomes at 6 months than targeted normocapnia. (Funded by the National Health and Medical Research Council of Australia and others; TAME ClinicalTrials.gov number, NCT03114033.).

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Anestesi och intensivvård (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Anesthesiology and Intensive Care (hsv//eng)

Keyword

Cardiac Arrest

Cardiology

Cardiology General

Clinical Medicine

Clinical Medicine General

Coma/Brain Death

Critical Care

Emergency Medicine

Emergency Medicine General

Hospital-Based Clinical Medicine

Neurology/Neurosurgery

Neurology/Neurosurgery General

Pulmonary/Critical Care

adult

adverse event

arterial carbon dioxide tension

Article

clinical feature

clinical outcome

coma

controlled study

female

Glasgow outcome scale

human

hypercapnia

incidence

intensive care unit

length of stay

life sustaining treatment

major clinical study

male

middle aged

mortality

open study

out of hospital cardiac arrest

outcome assessment

prognosis

randomized controlled trial

risk factor

Publication and Content Type

art (subject category)

ref (subject category)