Independent cough flow augmentation by glossopharyngeal breathing plus table thrust in muscular dystrophy.

OBJECTIVE: The purpose of the present study was to compare the unassisted cough peak flow (CPF) of patients affected by muscular dystrophy with CPF augmented by various techniques, including maximal depth glossopharyngeal breathing (GPB) combined with a subsequent self-induced thoracic or abdominal thrust. DESIGN: All of the motorized wheelchair-dependent patients with muscular dystrophy who had previously mastered GPB were trained at home to increase their cough efficacy. This training involved maneuvering their wheelchair against the edge of a specially built table to autonomously produce a thoracic and/or abdominal thrust timed to the opening of the glottis for an independently assisted cough. Both unassisted and variously assisted CPFs were compared. RESULTS: The 18 patients (17 men/1 woman) with muscular dystrophy, aged 21.1 ± 5.4 yrs, achieved variously assisted CPFs that were significantly higher than the spontaneous CPF (P < 0.001), with assisted CPFs but not unassisted CPFs that significantly exceeded a reported efficacious cough threshold value of 160 liters/min (P < 0.001). Moreover, increases in the CPFs by personal assistance including air stacking by manual resuscitator and thoracoabdominal thrust (326.4 ± 79.5 liters/min) or by GPB and thoracoabdominal thrust (326.4 ± 87.5 liters/min) were not significantly different (P = 0.07) from the CPFs independently attained by GPB plus independently maneuvering a wheelchair for a table thrust (310.3 ± 74.7 liters/min). CONCLUSIONS: The independently assisted (GPB plus table thrust) CPF was comparable to the CPFs that required personal assistance for air stacking and abdominal thrusts. Therefore, for patients with muscular dystrophy, this physical medicine technique and cough-assisted techniques that require personal intervention are strongly recommended.

Vital capacity in spinal muscular atrophy.

OBJECTIVE: This work describes and correlates plateau/maximum observed vital capacity (VC) with spinal muscular atrophy (SMA) severity and prognosis for autonomous breathing. DESIGN: SMA severity was correlated with VC, onset, paradoxical breathing, age at definitive dependence on continuous mechanical ventilation (DDCV), and age at first respiratory hospitalization and gastrostomy. RESULTS: Ten severe SMA 1A patients with DDCV before 6 mos of age had maximum observed and plateau VC of 100 ml or less, with plateaus for six at 10.3 (range, 3-48) mos. Another 120 had typical SMA 1B defined by any three of the following: acute respiratory failure before 12 mos of age, gastrostomy before 12 mos of age, DDCV before 10 yrs of age, and VC not exceeding 200 ml, with plateaus for 15 at 26.4 (6-138) mos. Fifteen were with mild type 1C defined by three of the following: VC exceeding 200 ml, acute respiratory failure after 1 yr of age, gastrostomy after 1 yr of age, and no DDCV before 10 yrs of age and had a plateau/maximum observed mean VC of 409 (range, 200-1175) ml at 8.9 (range, 7-10) yrs of age. Of 88 patients with SMA 2 and paradoxical breathing (2A), 16 had a mean plateau/maximum observed VC of 758 (range, 460-2100) ml. DDCV with no autonomous breathing always followed plateauing of VC. Types 2B, 3, and 4 patients attained normal VC. Intergroup VC differences were significant (P < 0.05) for 1A, 1B, 1C, 2A, and 2B-4. When intubated and "unweanable," 50-ml VC signaled the ability for autonomous breathing 1 to 21 days after extubation. CONCLUSIONS: VC should be monitored from birth. It correlates with prognosis with SMA 1A VCs not exceeding 100 ml or 1B 200 ml. Patients who attained 200 ml at any time (milder 1C) retain some ability to breathe after 10 yrs of age.