Management of Critically Ill Patients With Spinal Muscular Atrophy Admitted With Acute Respiratory Failure: The Authors' Reply

The authors wish to thank the editors for the opportunity to respond to Bach et al. The authors are unclear why there would be a lack of clarity regarding our noninvasive ventilation (NIV) approach to our subjects with spinal muscular atrophy (SMA). As known to Respiratory Care readers, the Journal style is to use NIV for noninvasive positive-pressure ventilation. In addition, we included our hospital neuromuscular disorders protocol in our recent publication,¹ which clearly highlights that we initially extubated all our critically ill acute-on-chronic pediatric subjects to continuous high-span bi-level positive airway ventilation using nasal interfaces and then subsequently maintained or weaned per our neuromuscular disorders triage scoring protocol. In addition, mechanical insufflation-exsufflation (MI-E) was combined with intrapulmonary percussive ventilation, high-frequency chest wall compression therapy, or percussion chest physiotherapy, not as a solo therapy, to provide and maintain individualized adequate airway clearance to our subjects. Bach et al questioned our MI-E settings of +30–+40 to −30 to −40; however, this does not seem suboptimal according to other available literature describing the use of MI-E in patients with neuromuscular disorders.^2–4 Similarly, that Bach et al claim that we mistook some of the facts in their 2002 publication⁵ is not entirely accurate. As stated in our discussion section, the reference to Bach et a1 2002 publication was in the context of our high first extubation success rate (91.2%) only, which, as highlighted by Bach et al, remains > 85% extubation success per attempt rate they reported even in the subsequent publications they included in their letter.

Over the last few years, elective tracheostomy placement has steadily increased in critically ill pediatric patients requiring prolonged mechanical ventilation, which is associated with a significant reduction in hospital length of stay and mortality.^6,7 Although we do not advocate for early tracheostomy placement in critically ill pediatric patients with SMA, as this might alter the patient's trajectory lifelong, an individualized approach should always be considered, primarily if a longer duration of invasive mechanical ventilation could be associated with worse clinical outcomes. Therefore, Bach et al claim that “four” (To clarify: 4 subjects in our study required multiple extubation attempts, and 3 subjects ultimately went on to receive a tracheostomy) of our subjects underwent tracheostomies because we used NIV strategies or MI-E settings different from what Bach et al recommend is simply inaccurate. In addition, as with many complex and challenging decisions in medicine, many factors were considered before tracheostomy was offered to these 3 subjects.

As stated in our article's introduction, this study aimed to describe our single-center's 15-year experience with invasive and noninvasive mechanical ventilation combined with aggressive airway clearance in critically ill children with SMA. We agree that there was a paradigm shift in the management of patients with SMA during these years and that the noninvasive respiratory management of SMA remains an essential area of clinical research since this population presents many challenges for providers for various reasons, including (1) standardized processes of care have not been fully developed; nor has (2) the nomenclature and nuances of the various therapies been well understood, as Bach et al pointed out; and (3) this population tends to gravitate to centers that specialize in this type of management, which leads to its own form of regionalization and specialization within centers as opposed to between them with some variable outcomes.

It is thus crucial that we share our individual center experiences and accept the differences between them. This dialogue between the authors and Bach et al highlights the need for this exchange and, more importantly, developing a multi-centered collaboration to compare optimal therapies and explore novel ones. As Bach et al suggest and our article shows, there is more than one way to care for this challenging and complex group of pediatric patients.