Results
There were 318 patients who met inclusion. The mean time for follow-up was 2.3 years (range = 0.1 to 7.8 years). The final status at the end of the follow-up period was N=140 (44%) alive with a tracheostomy in place, N=96 (30%) decannulated, N=61 (19%) died with a tracheostomy in place, and N=21 (6.6%) lost to follow up.
Tracheostomies were placed at a median age of 6.9 months (IQR: 4.1 – 49.2 months). The population was N=170 (53%) male and N=148 (47%) female. There were N=175 (55%) White, N=105 (33%) Black, N=15 (4.7%) Asian, and N=23 (2.7%) other. There were N=96 (30%) who identified as Hispanic. The preferred language was predominately English (N= 270, 86%) followed by Spanish (N=39, 12%). For further details, please refer to Table 1 .
Socioeconomic findings for the population were based on zip-code and county level measurements obtained from the Opportunity Insights’ databases on Social Capital and Opportunity Indices. The median (IQR) range for the economic connectiveness ratio was 0.73 (0.58-0.92); the support ratio was 0.85 (0.81-0.94); the fraction of single parents was 0.37 (0.28 – 0.38), and median household income was $53,442 ($49,529 – $62,463).
Table 2 shows associated conditions for the patient population. Notable findings include 41% (N=121) short gestation; N=72 (23%) having a history of respiratory distress syndrome; and N=133 (42%) being diagnosed with pulmonary hypertension. Other associated conditions included cardiac conditions (42%), birth hypoxia (11%), and tracheobronchomalacia (7.5%).
The median length of stay for the index stay when the tracheostomy was placed was 101 days (IQR: 52-166 days). The total number of patients discharged on a ventilator was N=272 (86%). The median time to ventilator liberation and eventual decannulation was 2.3 and 1.9 years, respectively. The median time to death for patient who expired with a tracheostomy in place was 0.70 years. The level of neurocognitive disability was considered severe in N=170 (59%) of children.
The number of children with BPD was N=136 (43%). Almost all were discharged on a ventilator. There were several statistically significant differences between children with tracheostomies with and without BPD. Children with BPD tended to be younger at the time of tracheostomy placement (5.2 months vs. 24.5 months, P <.001), have shorter gestational ages (28 weeks vs. 38 weeks,P <.001), and weighed less at tracheostomy placement (1.1 vs. 2.9 kg, P <.001). A higher proportion were Black (44% vs. 25%, P =.004). The level of social support by neighborhood level was slightly decreased among children with BPD (0.83 vs. 0.86, P =.021). Severe disabilities such as non-ambulant cerebral palsy or profound sensorineural hearing loss were also more common among those with BPD (63% vs. 57%, P =.003). See Table 3 for additional details.
Unadjusted estimates of time to mechanical ventilator liberation for children with BPD, compared to non-BPD children, showed a hazard ratio of 0.81 (95%, CI 0.63 – 1.04, P =.10). A confounder-adjusted estimation also did not find any variable associated with time to ventilator liberation. Additional analysis showed children with BPD spent a median of 2.92 years (IQR 1.60 – 4.03, P =.003) on mechanical ventilation compared to 1.84 years (IQR 0.84 – 3.60,P =.003) for children without BPD. See Table 4 for further details.
Unadjusted estimation of time to decannulation for children with BPD yielded HR=0.92 (95% CI, 0.62 – 1.38). The adjusted model found the time on a ventilator interacted with BPD (see Table 5 ). The model suggests that children with BPD on a ventilator are more likely to take longer to decannulate than a child on a ventilator who does not have BPD. Using the 25th, 50th, and 75th percentiles for time to decannulation, the median times to decannulation would be 2.6, 3.2, and 4.5 years for BPD and 1.8, 3.1, and 5.8 years for non-BPD children. The model’s goodness-of-fit is presented in Figure 1 . In addition, statistical significance held when using jackknife regression variance components estimation for model validation suggesting that outliers did not have a substantial impact on regression coefficients.
The unadjusted survival analysis for time to mortality found that the HR for BPD was 0.58 (95% CI, 0.34 – 0.98). The adjusted model includes pulmonary hypertension as a variable of significance (aHR = 2.5, 95% CI: 1.43 – 4.40) while reducing the confidence interval of the effects of BPD on mortality (aHR = 0.38, 95% CI: 0.22 – 0.69). The model did not reveal a statistical interaction between the two variables suggestive of an additive effect (Table 6) . Goodness-of-fit plots (Figure 2 ) and jackknife regression of the model suggested a good fit. Additional subgroup or sensitivity analyses were not performed.