PURPOSE: To study the role of various factors that predict failure of extubation after successful spontaneous breathing trial (SBT).
METHODS: This was a prospective observational study at an inner city community hospital. Consecutive subjects intubated and mechanically ventilated in the medical intensive care unit were enrolled. Twenty-six patients were studied over a two month period. Five subjects were excluded as they were ventilated for less than 48 hours. Eligible subjects were followed up for 72 hours post-extubation. Multiple variables including amount of endotracheal secretions, mental status, arterial blood gas (ABG) during SBT and post-extubation were collected. The study is ongoing and enrollment would continue for a year to recruit additional subjects.
RESULTS: The subjects were divided into two groups. The first group included patients who were successfully extubated (n=15). The second group included six patients (28%) who failed extubation. The baseline characteristics of the two groups were similar including age, sex, race, body mass index (BMI), Acute Physiology and Chronic Health Evaluation (APACHE) II score and hemoglobin. The two groups also did not have any significant difference in the pH, pCO2, pO2, tidal volume, FiO2 and amount of endotracheal secretions while on mechanical ventilation. The respiratory shallow breathing index (RSBI), pH and pO2 during SBT were also similar in both groups. The pCO2 during SBT was higher in the group who failed extubation (mean 44.2, standard deviation [SD] 7.4) as compared to those who were successfully extubated (mean 37.3, SD 5.7). This difference was statistically significant (p=0.03). The post-extubation pCO2 (mean 39.2 vs. 51.6), post-extubation respiratory rate (mean 21.1 vs. 26.6) and post-extubation mental status (Glasgow coma scale score mean 13.6 vs. 11.2) were noted to be better in the successfully extubated group as compared to the failed group, although this did not reach statistical significance.
CONCLUSION: Hypercapnia during SBT is a predictor for extubation failure.
CLINICAL IMPLICATIONS: Physicians should be careful extubating patients who develop hypercapnia during SBT as these patients have a higher risk of reintubation.
DISCLOSURE: Gagandip Singh, None.