Objective: To assess whether the respiratory oxygenation index (ROX index) measured after the start of high-flow nasal cannula oxygen therapy can help identify the need for intubation in patients with acute respiratory failure due to coronavirus disease 2019.
Methods: This retrospective, observational, multicenter study was conducted at the intensive care units of six Brazilian hospitals from March to December 2020. The primary outcome was the need for intubation up to 7 days after starting the high-flow nasal cannula.
Results: A total of 444 patients were included in the study, and 261 (58.7%) were subjected to intubation. An analysis of the area under the receiver operating characteristic curve (AUROC) showed that the ability to discriminate between successful and failed high-flow nasal cannula oxygen therapy within 7 days was greater for the ROX index measured at 24 hours (AUROC 0.80; 95%CI 0.76 - 0.84). The median interval between high-flow nasal cannula initiation and intubation was 24 hours (24 - 72), and the most accurate predictor of intubation obtained before 24 hours was the ROX index measured at 12 hours (AUROC 0.75; 95%CI 0.70 - 0.79). Kaplan-Meier curves revealed a greater probability of intubation within 7 days in patients with a ROX index ≤ 5.54 at 12 hours (hazard ratio 3.07; 95%CI 2.24 - 4.20) and ≤ 5.96 at 24 hours (hazard ratio 5.15; 95%CI 3.65 - 7.27).
Conclusion: The ROX index can aid in the early identification of patients with acute respiratory failure due to COVID-19 who will progress to the failure of high-flow nasal cannula supportive therapy and the need for intubation.
Boswellia serrata is an herbal extract from the Boswellia serrata tree that has anti-inflammatory and analgesic properties and alleviates pain caused by rheumatoid arthritis, gout, osteoarthritis, and sciatica. Syndrome of inappropriate antidiuretic hormone secretion accompanied by hyponatremia, seizures, and rhabdomyolysis as a manifestation of Boswellia serrata intoxication has not been reported previously. A 38-year-old female suffered clinically isolated syndrome and has since been regularly taking B. serrata capsules (200mg/d) to strengthen her immune system. She experienced hypersensitivity to light, ocular pain, nausea, dizziness, and lower limb weakness four days after receiving her first BNT162b2 vaccine dose, and she increased the dosage of B. serrata to five capsules (1000mg/d) one week after vaccination. After taking B. serrata at a dosage of 1000mg/d for 3 weeks, she was admitted to the intensive care unit because of a first, unprovoked generalized tonic-clonic seizure. The patient's workup revealed syndrome of inappropriate antidiuretic hormone secretion, which resolved completely upon treatment and discontinuation of B. serrata. In summary, B. serrata potentially causes syndrome of inappropriate antidiuretic hormone secretion when it is taken at high doses. Patients should not self-medicate.