What can we Learn from Patients who Died from Covid-19 Following Escalation to a Respiratory High Dependency Unit for Trial of Non-Invasive Respiratory Support?

Background: Covid-19 infection is associated with significant risk of death, particularly in older, comorbid patients. Emerging evidence supports use of non-invasive respiratory support (CPAP and high-flow nasal oxygen [HFNO]) in this context, but little is known about its use in patients receiving end-of-life care. Methods: This was a retrospective study of 33 patients who died of Covid-19 on the Respiratory High Dependency Unit at the John Radcliffe Hospital, Oxford between 28/03/20 and 20/05/20. Data was sourced via retrospective review of electronic patient records and drug charts. Results: Patients dying from Covid-19 on the Respiratory HDU were comorbid with median Charlson Comorbidity Index 5 (IQR 4-6); median age 78 (IQR 72-85). Respiratory support was trialled in all but one case with CPAP being the most common form of first line respiratory support (84.8%) however, was only tolerated in 44.8% of patients. Median time to death was 10.7 days from symptom onset (IQR 7.5-14.6) and 4.9 days from hospital admission (IQR 3.1-8.3). 48.5% of patients remained on respiratory support at the time of death. Conclusions: End-of-life care for patients with Covid-19 remains a challenge. Patients tend to be frail and comorbid with a rapid disease trajectory. Non-Invasive Respiratory Support may play a key role in symptom management in select patients, however, further work is needed in order to identify patients who will most benefit from Respiratory Support and those for whom withdrawal may prevent unnecessary distress at the end of life or potential prolongation of suffering.

Relative accuracy of algorithm-based prescription of nasal CPAP in OSA.

BACKGROUND: Patients with OSA on nasal continuous positive airway pressure (CPAP) have considerable night-to-night variation in their pressure requirements, suggesting that a one-night titration might not be very precise. This study investigates the likely error incurred using a one-night titration, and explores whether an algorithm-based approach to determine the pressure is as accurate. METHODS: Thirty patients with OSA used an autotitrating CPAP device for 28 nights and the average was regarded as the 'reference' pressure for that patient. Using estimates of precision and bias, this 'reference' pressure was compared with (1) an algorithm-derived pressure (based on neck circumference and OSA severity), (2) a one-night titration (using four alternative nights), and (3) a fixed pressure of 10 cmH2O. RESULTS: The mean 'reference' pressure for the group was 9.83 (SD 2.12) cmH2O. There was little bias from any of the alternatives. However, the precision varied between 1.65 and 2.45 cmH2O for the four one-night titrations, was 2.00 for the algorithm, and was 2.12 using a fixed pressure of 10 cmH2O. CONCLUSIONS: Considerable night-to-night variation means that a one-night titration is not very precise and is subject to random variation. A one-night titration has a similar inaccuracy to that resulting from using an algorithm, based on OSA severity and neck circumference. Setting all patients with OSA at 10 cmH2O is little worse.

A novel, simplified approach to starting nasal CPAP therapy in OSA.

BACKGROUND: Due to ever increasing referral rates, we have had to move the nasal CPAP induction program for patients with obstructive sleep apnoea (OSA) out of the sleep laboratories and into an outpatient setting. We report the effects this has had on patient outcomes. METHODS: The last 75 patients with OSA who had an overnight CPAP titration in the sleep laboratory (group 1) were compared with the first 75 coming to an afternoon clinic and set up on CPAP in groups, and who had their CPAP pressure determined from an algorithm (group 2). They were assessed at 1 and 11 months using the Epworth Sleepiness Score, compliance with CPAP (h/night), whether still using CPAP, and the number of clinic appointments required in the first 11 months. RESULTS: The two groups were similar at baseline. There were no differences in any of the outcome measures. ESS values fell from 14.6 to 5.0 and from 14.0 to 5.1 at 11 months in groups 1 and 2, respectively: compliance, 5.2 versus 5.1 h/night; clinic appointments, 1.75 versus 1.96; discontinuation rates at 1 month, 8% and 7%, and at 11 months, 25% and 21%. CONCLUSIONS: Using these simple outcome measures, we have shown that using an outpatient-based approach, and CPAP pressure based on an algorithm, have not reduced the efficacy of our CPAP induction program for patients with OSA.