Cerebrovascular autoregulation and arterial carbon dioxide in patients with acute respiratory distress syndrome: a prospective observational cohort study

Annals of Intensive Care

Table 3 Linear mixed model—estimates of fixed effects

Parameter	Estimate	95% CI—low	95% CI—up	p
Intercept	0.177	− 0.059	0.414	0.139
No early hypercapnia (vs. early hypercapnia = PaCO₂ ≥ 50 mmHg)	0.023	− 0.054	0.100	0.556
Sedation
Mixed sedation (vs. no sedation)	− 0.042	− 0.217	0.133	0.635
Intravenous sedation (vs. no sedation)	− 0.074	− 0.235	0.087	0.363
Inhalational sedation (vs. no sedation)	− 0.076	− 0.260	0.107	0.410
ARDS severity
Mild (vs. severe)	0.032	− 0.062	0.126	0.498
Moderate (vs. severe)	− 0.018	− 0.102	0.065	0.663
Age (per year increase)	0.001	− 0.001	0.004	0.275
Hypocapnia during the measurement period^a	0.155	0.014	0.296	0.032
ARDS etiology (community-acquired vs. hospital-acquired)^b	0.047	− 0.027	0.122	0.208

The variables position (prone vs. supine), inhalational nitric oxide, extracorporeal membrane oxygenation, and the Sequential Organ Failure Assessment score during measurement were included in the initial model and eliminated during the stepwise-backwards reduction
ARDS: acute respiratory distress syndrome
^aVs. Normo- and hypercapnia
^bEtiologies were categorized as “community-acquired” and “hospital-acquired” for the linear mixed model