Abstract
Background:
The arterial blood gas (ABG) parameters of patients admitted to intensive care units (ICUs) with acute neuromuscular respiratory failure (NMRF) and non-NMRF have not been defined or compared in the literature.
Methods:
We retrospectively collected the initial ABG parameters (pH, PaCO
2
, PaO
2
, and HCO
3
) of patients admitted to ICUs with acute respiratory failure. We compared ABG parameter ranges and the prevalence of abnormalities in NMRF versus non-NMRF and its categories, including primary pulmonary disease (PPD) (chronic obstructive pulmonary disease, asthma, and bronchiectasis), pneumonia, and pulmonary edema.
Results:
We included 287 patients (NMRF,
n
= 69; non-NMRF,
n
= 218). The difference between NMRF and non-NMRF included the median (interquartile range (IQR)) of pH (7.39 (7.32–7.43), 7.33 (7.22–7.39),
p
< 0.001), PaO
2
(86.9 (71.4–123), 79.6 (64.6–99.1) mmHg,
p
= 0.02), and HCO
3
(24.85 (22.9–27.8), 23.4 (19.4–26.8) mmol/L,
p
= 0.006). We found differences in the median of PaCO
2
in NMRF (41.5 mmHg) versus PPD (63.3 mmHg), PaO
2
in NMRF (86.9 mmHg) versus pneumonia (74.3 mmHg), and HCO
3
in NMRF (24.8 mmol/L) versus pulmonary edema (20.9 mmol/L) (all
p
< 0.01). NMRF compared to non-NMRF patients had a lower frequency of hypercarbia (24.6% versus 39.9%) and hypoxia (33.8% versus 50.5%) (all
p
< 0.05). NMRF compared to PPD patients had lower frequency of combined hypoxia and hypercarbia (13.2% versus 37.8%) but more frequently isolated high bicarbonate (33.8% versus 8.9%) (all
p
< 0.001).
Conclusions:
The ranges of ABG changes in NMRF patients differed from those of non-NMRF patients, with a greater reduction in PaO
2
in non-NMRF than in NMRF patients. Combined hypoxemia and hypercarbia were most frequent in PPD patients, whereas isolated high bicarbonate was most frequent in NMRF patients.