RESULTS
The data extraction process yielded a dataset of 132,446 unique patients
who had a diagnosis of COVID-19 either on admission or during their
stay. Of these 13,401 (10.1%) were admitted to critical care as part of
a hospital stay. Of those admitted to critical care, 7,993 (59.6%) had
advanced respiratory support and 2,200 (16.4%) had a tracheostomy
procedure recorded.
Tracheostomy use in critical care patients changed markedly over time.
Use of tracheostomy and associated mortality rates for month of
discharge are presented in Figure 1, tracheostomy use for each region
over time by month of discharge are presented in Figure 2. By discharge
date, tracheostomy rates were very low for patients discharged in March
(2.6%), peaked for discharges in June (36.7%) and declined thereafter
to 4.1% in October. This trend was seen across all regions. Mortality
rates in those with a tracheostomy revealed a mirror image trend, with
the lowest death rates seen at times of highest tracheostomy use. When
plotted by admission month the pattern is similar, but with an earlier
and smaller peak in the proportion of patients with a tracheostomy
(11.9% in February, 20.5% in April). However, there was a similar
decline in the proportionate use of tracheostomy in late summer 2020
(3.8% in August).
The profile of those admitted to hospital, those admitted to critical
care and those who had advanced respiratory support and a tracheostomy
is summarised in Table 1 . Those admitted to critical care were
more likely to be aged 40-69 years and less likely to be aged 70 years
and over than the general hospitalised population. They were also more
likely to be male and from a non-White ethnic background. The
deprivation profile of those admitted to critical care reflected the
wider population. Obese patients were over-represented in those admitted
to critical care and patients with dementia, cardiovascular disease,
renal disease and cancer were under-represented. The profile of those
who were recorded as having a tracheostomy was similar to the wider
critical care population, although there was a smaller percentage of
people aged 70 years and over with a tracheostomy.
Factors associated with having a tracheostomy for those admitted to
critical care were explored using multilevel logistic regression and the
results are presented in Table 2 . Compared to the 18-39 years
age group, tracheostomy was significantly more common in the 40-79 years
age group and significantly less common in the 80 years and over age
group. Tracheostomy was significantly more common in males, in Asian and
Black ethnic groups and in patients with cerebrovascular disease.
Tracheostomy was less common in patients with peripheral vascular
disease, chronic heart failure, acute myocardial infarction, connective
tissue/rheumatic disease, moderate/severe liver disease, renal disease
and cancer.
In patients admitted to critical care, outcomes for those with and
without a tracheostomy are presented in Table 3 with the
adjusted association of tracheostomy with each outcome. Tracheostomy was
significantly associated with reduced odds of in-hospital mortality and
increased odds of length of stay greater than the median after adjusting
for covariates.
The time from hospital admission to critical care admission was the same
for both those who survived to discharge and those who died during their
stay: median 1 day (IQR 0 to 3). Of those with a tracheostomy, 120
(5.5%) had tracheostomy malfunction recorded during their stay. Of
those with a malfunction recorded, 36 died in hospital (30.0%) and in
the 2080 without a malfunction 437 (21.0%) died in hospital.
Of the 2,200 patients with a tracheostomy, data on time from critical
care admission to tracheostomy were available for 1,777 (80.8%)
patients. Data on the timing of tracheostomy from critical care
admission are presented in Table 4 for those who died and those
who survived to discharge. Patients who underwent a tracheostomy at ≤ 14
days from critical care admission and survived to discharge had a
shorter hospital and critical care stay both overall and
post-tracheostomy. Undergoing a tracheostomy ≤ 14 days from critical
care admission was associated with significantly shorter time from
tracheostomy to critical care discharge (β = -0.100 (95% CI -0.170 to
-0.031) and hospital discharge (β = -0.061 (95% CI -0.115 to -0.007).