Discussion
This study examines the association between diuretic weaning strategy and duration of home oxygen in the year following discharge from the NICU in infants with BPD in the setting of guidelines for management of home oxygen. We found that actively weaning diuretics was not associated with longer duration of home oxygen, but passively weaning diuretics was associated with longer duration of home oxygen. We also found that infants started on inhaled corticosteroids after NICU discharge and whose parents weaned home oxygen off-protocol experienced a longer duration of home oxygen.
Infants with BPD discharged with home oxygen therapy are often also discharged with diuretics. It has been shown that diuretics in infants with BPD may improve pulmonary mechanics such as improved pulmonary compliance, lung function and oxygenation.2,4,10-13However, diuretics do not decrease oxygen dependence in the inpatient setting, and evidence is limited regarding the impact of long term treatment.3,14-16 The American Thoracic Society (ATS) guidelines for outpatient management of diuretics suggest that infants with post-prematurity respiratory disease who were discharged home with diuretic therapy should have diuretics discontinued in a careful manner; the guidelines also recommend avoiding routine use of diuretics.4,6,16 Partially due to the wide variation in both home oxygen and use of respiratory medication use between centers, there are few recommendations regarding how and when to wean diuretics specifically in conjunction with home oxygen therapy.5,16 Bhandari et al. described an active medication taper in infants with stable BPD, though few infants in that study were also receiving home oxygen therapy. 17 Palm et al. found that most infants with home oxygen therapy have diuretics discontinued prior to home oxygen discontinuation, though this study did not address the specific method of diuretic weaning.18 Using our guidelines, we were able to effectively start many infants’ weaning process for supplemental oxygen and diuretics in the same visit.
We found that infants started on inhaled corticosteroids after NICU discharge had a longer duration of home oxygen therapy, similar to recent findings by White and colleagues among patients in a trial of recorded home oximetry.4 As with diuretics, the prescribing pattern of inhaled corticosteroids varies between institutions.18 Infants in our center are variably discharged home from the NICU on inhaled corticosteroids; in clinic we follow a guideline to prescribe inhaled corticosteroids only if the infant has recurrent coughing and wheezing, following the recent published ATS recommendations.6 It is unlikely that the longer duration of home oxygen therapy was related to inhaled corticosteroids themselves but rather to intercurrent illness; we also noted that respiratory rehospitalizations, emergency department visits, and systemic corticosteroid bursts were associated with longer duration of home oxygen therapy. Nonetheless, our data provide reassurance that starting routine inhaled corticosteroids in infants with BPD discharged with home oxygen therapy does not appear beneficial in decreasing the length of home oxygen.
We found that infants whose parents did not follow the home oxygen weaning protocol ultimately had a longer duration of home oxygen. Off-protocol weaning issues included some parents taking infants off supplemental oxygen before being instructed to do so, or delays in implementing the home oxygen weaning process. Since half of infants with off-protocol weaning had either failed an overnight pulse oximetry study or had ED visits or admissions, it may be that these infants had a longer duration of home oxygen due to the severity of their illness, rather than the weaning process itself. Other infants and their families experienced delays in clinic appointments or ordering of home oximetry testing to discontinue oxygen, which contributed to the longer duration of home oxygen. For these infants and their families, implementing additional educational and clinical interventions to reduce the family impact of home oxygen therapy may have the potential to shorten the length of oxygen. This cohort was followed before our newer strategy of offering telehealth visits which helps families who have difficulty getting back and forth. It will be interesting in future studies how the utilization of remote health strategies effects the length of home oxygen.
Strengths of this study were the high degree of follow up and use of pre-specified clinical guidelines. This biggest limitation was that it was a single-center study. We were not able to control the exact time of appointments which may affect the exact duration of home oxygen and medications. We did evaluate other proxy measures of home oxygen weaning to try to mitigate this weakness. Some factors associated with prolonged home oxygen weaning are hard to evaluate as “independent” risk factors, such as use of systemic corticosteroids, respiratory readmissions, and emergency department encounters, since these are all likely single events related to acute illness.
In the setting of a standardized clinical guideline for weaning home oxygen in infants with BPD, actively weaning diuretics was not associated with longer duration of home oxygen. We did find that beginning inhaled corticosteroids after NICU discharge and off-protocol weaning were associated with a longer duration of home oxygen. These data can serve as a baseline information to implement and test standardized strategies for diuretic weaning. These results also highlight the need for future studies regarding the use of inhaled corticosteroids in infants with BPD, telehealth visits, more remote health strategies for weaning home oxygen and parental education interventions effects on the duration of home oxygen.