Percentages may not total 100 because of rounding. IQR denotes interquartile range, HIV human immunodeficiency virus, PaO2 partial pressure of arterial oxygen, FiO2 fraction inspirated oxygen, PaCO2 partial pressure of arterial carbon dioxide, cm of H2O centimeters of water, PTT partial thromboplastin time. P values not shown in the table were non-significant

*P-value for comparison of Early PDT group to Late PDT group using Wilcoxon Rank-sum test for continuous variables and Chi-square test for categorical variables

** P-value for comparison of Early PDT group to No Tracheostomy group using Wilcoxon Rank-sum test for continuous variables and Chi-square test for categorical variables

a Information in race and ethnic group was obtained from entries in medical records as reported by patients

b The body mass index is the weight in kilograms divided by the square of the height in meters.

c Defined as multiple sedatives and a paralytic infusion or paralytic boluses over 2 or more days

d Defined as a dose of IV steroids over 1-2 mg per Kg over 3 or more consecutive days

e Defined as prone positioning > 2 times over 2 or more days

(7)

f Full dose anticoagulation with therapeutic anti-Xa level>0.3IU/ml and/or PTT>45 sec

(8)

Table 3s and Figure 1s. Distribution of Aerosol Mass Concentration Reading for PDT during COVID-19, Trach Collar, and Patient Rooms Pre-Procedure

Procedure Type (n=total readings) Number of Patients

Exposure

Time (min) Median Total Aerosol Exposure (mg)

Median Aerosol

Concentration Reading (IQR) (mg/m³)

Maximum Aerosol Concentration Reading (mg/m³)

Mean Aerosol Concentration Reading (mg/m³)

COVID-19 Tracheostomy (n=7672) 15 8 0.49 0 (0-0.001) 2.2 0.003

Trach Collar (n=4500) 9 8 1.6 0.001 (0·001-0.004) 150 3.1

Room Pre-Procedure (n=2067) 15 4 0.35 0 (0-0.002) 0.71 0.003

We found that the median total aerosol exposure concentration readings (Figure 3S-a) and the distribution of aerosol reading for the new PDT procedure were significantly lower compared to the trach collar (p<·0001) and similar to the pre-procedure room readings. For the comparison of aerosol concentration readings between procedure types, the nonparametric Mood median test was used (α<0·05). Analyses were

performed using SAS, version 9·4 (SAS Institute, Cary NC).

Figure 1s-a. Figure 1s-b

(9)

Figure 2s. Balance summary of covariates for patients with Early Tracheostomy and No

Tracheostomy before and after matching on propensity scores with caliper 0.5. Standardized mean differences in the unmatched and matched sample (297 patients). All the p values in all the

variables used in the propensity score matched samples are non-significant.

(10)

Figure 3s. Balance summary of covariates for patients with Early Tracheostomy and Late Tracheostomy before and after matching on propensity scores. Standardized mean differences in the unmatched and matched sample (205 patients). All the p values in all the variables used in the propensity score matched samples are non-significant

(11)

Figure 4s. Balance summary of covariates for patients with Early Tracheostomy and Not Early Tracheostomy (Patients remained intubated that did not have a tracheostomy or later (>13 days) have a tracheostomy) before and after matching on propensity scores with caliper 0.5. Standardized mean differences in the unmatched and matched sample (386 patients). All the p values in all the variables used in the propensity score matched samples are non-significant

table of contents

Supplementary Appendix