Researchers investigating respiratory treatment in patients with spinal muscular atrophy (SMA) type 1 recommended clinicians to not wait for signs of hypoventilation to appear before initiating noninvasive ventilation (NIV), as published in Pediatric Pulmonology.

“The recent development of disease-modifying treatments in [SMA] type 1 shifted these patients’ management from palliative to proactive,” Menard and colleagues wrote. This is why there is renewed interest in optimizing respiratory support for patients with SMA type 1 since respiratory complications are a leading cause of death.

However, studies show that many physicians start their patients on NIV because of repeated respiratory exacerbations requiring hospitalizations and not usually because of hypoventilation. The researchers wanted to assess whether capnia was a good criterion to decide the right time to introduce respiratory support.

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They hence investigated patients’ nocturnal gas exchanges prior to NIV initiation and their clinical evolution and conducted a multicentric retrospective study that involved 17 children with SMA type 1 who were started on nusinersen between 2016 and 2018.

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The results demonstrated that 13 (76%) of patients were started on NIV. Eleven of them (65%) were started on nusinersen due to repeated hospitalizations and intensive care unit admissions. Eight patients had blood gases performed prior to NIV initiation and those tests did not reveal any abnormalities. Meanwhile, nocturnal gas exchange recordings performed prior to NIV initiation in 8 patients showed no signs of hypoventilation, nor spending time with transcutaneous carbon dioxide >50 mmHg during sleep.

“More importantly, this study shows that a delay in ventilatory support initiation might result in pulmonary atelectasis and other respiratory complications that will negatively impact the patients’ respiratory evolution,” the authors wrote.

The key question throughout this study is: when is the right time to start patients with SMA type 1 on NIV? Menard and colleagues recommended that the decision on whether to start NIV should not rely solely on nighttime recording results, but also clinical examination, thoracic circumference/head circumference ratio, and respiratory scoring systems.


Menard J, Seferian AM, Fleurence E, et al. Respiratory management of spinal muscular atrophy type 1 patients treated with nusinersenPediatr Pulmonol. Published online March 20, 2022. doi:10.1002/ppul.25899