Airway musculature

Fig. 1. Innervation of relevant upper airway musculature. From [13] with permission from...

Assessment of neuromuscular block usually is performed by stimulation of the ulnar nerve. Responses are monitored from compound action potentials or muscle tension developed in the adductor pollicis (thumb) muscle. Responses to repetitive or tetanic stimuli are most useful for evaluation of blockade of transmission. Thus, stimulus schedules such as the train of four and the double burst or responses to tetanic stimulation are preferred procedures. Rates of onset of blockade and recovery are more rapid in the airway musculature (jaw, larynx, and diaphragm) than in the thumb. Hence, tracheal intubation can be performed before onset of complete block at the adductor pollicis, whereas partial recovery of function of this muscle allows sufficient recovery of respiration for extubation. 

Airway. Airway protection in stroke patients may require immediate intervention. An impaired level of consciousness combined with emesis can occur in patients with increased intracranial pressure (ICP) and posterior circulation stroke. Vertebrobasilar ischemia may affect medullary respiratory centers and cause apnea, or more commonly, paralysis of pharyngeal and tongue musculature leading to obstruction of the airway. The patient may require gastric suction and intubation to protect the airway from aspiration of gastric contents. An oral airway or nasal trumpet can be helpful if the patient has an upper airway obstruction. 

Few, if any, patients with NMD should be left to develop unexpected ventilatory failure as appropriate assessment, self-management education, and follow-up will identify disease progression and risk of respiratory complications. When ventilatory failure occurs, tracheostomy tubes can be avoided, for the most part, irrespective of the degree of ventilator dependence, with the exception of those with insufficient bulbar-innervated musculature for speech, deglutition, and airway protection. Those with indwelling tracheostomy tubes should be offered decannulation as part of their rehabilitation, irrespective of the extent of their respiratory muscle failure. The only exceptions to this therapy are patients with advanced bulbar ALS or those with rare facioscapulohumeral muscular dystrophy, who lose all bulbar-innervated muscle function and aspirate saliva to the extent of Sao2 remaining below 95% (13). 

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