End-Tidal Carbon Dioxide as a Prognostic Feature in Pulmonary Arterial Hypertension.

ABSTRACT:

Rationale

Pulmonary arterial hypertension (PAH) is characterized in part by increased dead space ventilation, which can be estimated noninvasively at the bedside by measurement of end-tidal CO₂ (ETco₂).

Objectives

Prior work has demonstrated that ETco₂ is lower in patients with PAH than in control patients, but whether ETco₂ has prognostic value is unknown. We hypothesized that lower measurements of ETco₂ in patients with PAH correlate with worse long-term outcomes.

Methods

Patients with PAH seen in our referral clinic were prospectively recruited for ETco₂ measurement between September 2009 and February 2010. Vital status as of July 2015 was documented using medical records and the Social Security Death Index.

Results

Eighty-two patients were followed for a median of 60 months. Twenty-six patients died, and two were lost to follow-up. Patients who died were more likely to be older (58.5?±?14.9 vs. 47.6?±?12.2 yr; P?2 in survivors was 30.5?±?4.8 mm Hg, whereas mean ETco₂ in patients who died was 27.1?±?4.2 mm Hg (P?=?0.004). After stratification by median baseline ETco₂ of 29 mm Hg, survival in each group was analyzed. Patients with lower ETco₂ had shorter survival (P?=?0.006). Cox regression analysis with ETco₂ as a continuous variable revealed the hazard ratio to be 0.88 (95% confidence interval, 0.80-0.97; P?=?0.006). In 52 patients with more than one measurement a median of 17 months apart, ETco₂ was unchanged.

Conclusions

Our single-center data suggest that lower ETco₂ is associated with shorter survival and that ETco₂ is stable over time in patients with PAH.

SUBMITTER: Welch CE 

PROVIDER: S-EPMC6850742 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature