Paeds · neurology-neurodisability-and-neuromuscular

Acute neuromuscular respiratory failure

Also known as Neuromuscular ventilatory failure · Respiratory pump failure · Respiratory muscle failure · Ventilatory failure from neuromuscular weakness

Fellowship guide to acute neuromuscular respiratory failure in children. Covers the respiratory pump from brainstem to diaphragm and bulbar muscles, the two mechanisms of failure, hypercapnic pump failure and hypoxaemic bulbar aspiration, the bedside forced vital capacity, maximum inspiratory pressure, and maximum expiratory pressure monitoring with the Lawn twenty-thirty-forty thresholds and the Durand and Sharshar predictors of ventilation, the differential across the motor unit from anterior horn cell to muscle including spinal muscular atrophy, Guillain-Barre syndrome, myasthenia gravis, infant botulism, and Duchenne muscular dystrophy, the airway decision between non-invasive ventilation when bulbar function is intact and intubation for bulbar weakness, the avoidance of suxamethonium and use of rocuronium one milligram per kilogram, cough augmentation with mechanical insufflation-exsufflation, and the disease-specific and long-term ventilation decisions.

high12 referencesUpdated 16 July 202616 min readVerification in progress

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A normal oxygen saturation does not exclude neuromuscular respiratory failure; carbon dioxide climbs while oxygenation is preserved, so the child can arrest with a reassuring saturationMeasure bedside forced vital capacity every two to six hours; a value under twenty millilitres per kilogram, a fall of over thirty percent, or maximum inspiratory pressure weaker than minus thirty centimetres of water predict the need for ventilationBulbar weakness with a weak cough, pooled secretions, and a soft voice predicts aspiration; this is an indication for intubation, not non-invasive ventilationNever give suxamethonium to a child with a denervating or chronic neuromuscular disease; it can trigger life-threatening hyperkalaemia and cardiac arrest; use rocuronium one milligram per kilogramNon-invasive ventilation supports pump failure only when bulbar function is intact; it does not protect the airway and will fail when bulbar weakness developsDo not wait for a rising carbon dioxide on the blood gas before escalating; by the time the gas is abnormal the child is already decompensating

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Recognises that acute neuromuscular respiratory failure is a failure of the respiratory pump rather than the lungs, presents with hypercapnia before hypoxaemia, and is most often due to Guillain-Barre syndrome in a previously well childMonitors bedside forced vital capacity every two to six hours and states that a value under twenty millilitres per kilogram, a fall of over thirty percent, or bulbar weakness with a weak cough are the triggers for intensive care and airway protectionStates that non-invasive ventilation can support a child with intact bulbar function but that bulbar weakness with aspiration is an indication for intubation, and that suxamethonium must be avoided because of dangerous hyperkalaemia in denervated muscleApplies the Lawn twenty-thirty-forty monitoring framework using forced vital capacity, maximum inspiratory pressure, and maximum expiratory pressure, and the Durand and Sharshar predictors of ventilation, and justifies when to intubate before blood-gas decompensationDistinguishes pump failure causing hypoventilation and hypercapnia from bulbar failure causing aspiration and hypoxaemia, and runs the differential across the motor unit from anterior horn cell to muscle including spinal muscular atrophy, Guillain-Barre syndrome, myasthenia gravis, botulism, and muscular dystrophyManages cough augmentation with mechanical insufflation-exsufflation, times non-invasive ventilation versus intubation and tracheostomy, and coordinates retrieval, intensive care, disease-modifying therapy, and the long-term ventilation decisionThe forced vital capacity threshold under twenty millilitres per kilogram, the over thirty percent decline rule, and the maximum inspiratory and expiratory pressure thresholds for intensive care escalationThe two mechanisms of failure, hypercapnic pump failure and hypoxaemic bulbar aspiration, and the differential of acute flaccid weakness across the motor unitThe avoidance of suxamethonium and use of rocuronium for rapid sequence intubation, the role of non-invasive ventilation when bulbar function is intact, and cough augmentation with mechanical insufflation-exsufflationRuns the structured assessment, respiratory monitoring, and airway decision for a child with progressive neuromuscular weakness while excluding the mimics and arranging tertiary retrievalDecides on and times non-invasive ventilation versus intubation using serial forced vital capacity and bulbar assessment, and coordinates intensive care, disease-specific therapy, and rehabilitationCounsels the family on the cause, the projected course from days to months depending on the diagnosis, the long-term ventilation and quality-of-life decisions in chronic disease, and the safety-netLevel 1: Recognition that a child with progressive weakness, a weak cough, and shallow breathing has neuromuscular respiratory failure and that a normal oxygen saturation does not exclude itLevel 2: Application of bedside spirometry with forced vital capacity thresholds, the distinction between pump and bulbar failure, and the timing of intensive care escalationLevel 3: Coordination of non-invasive ventilation, intubation avoiding suxamethonium, cough augmentation, disease-specific therapy, and the long-term ventilation decision in chronic neuromuscular diseaseAcute neuromuscular respiratory failure as a failure of the respiratory pump causing hypercapnia before hypoxaemia, with Guillain-Barre syndrome the commonest acute cause in childrenThe forced vital capacity monitoring thresholds under twenty millilitres per kilogram and the over thirty percent decline rule, and the indication for intubation in bulbar weaknessThe avoidance of suxamethonium in denervated muscle, the role of non-invasive ventilation when bulbar function is intact, and the differential across the motor unit including botulism and myasthenia gravisStructured assessment of a child with progressive neuromuscular weakness including serial bedside spirometry, bulbar and cough assessment, and arterial blood-gas interpretationRecognition of the intensive care and intubation triggers and the timing of disease-specific therapy, and the exclusion of acute flaccid myelitis, transverse myelitis, and cord compressionCommunication of the diagnosis, the projected recovery, and the long-term ventilation decision to the family with honesty about uncertaintyAcute neuromuscular respiratory failure as respiratory pump failure with hypercapnia preceding hypoxaemia, and the common causes in United States children including Guillain-Barre syndrome and acute flaccid myelitisForced vital capacity monitoring with the twenty millilitres per kilogram threshold and the role of non-invasive ventilation and intubation, and the avoidance of suxamethoniumThe differential across the motor unit, the role of cough augmentation, and the disease-specific therapy for spinal muscular atrophy, myasthenia gravis, and infant botulismRecognition of acute neuromuscular respiratory failure as pump failure with hypercapnia before hypoxaemia and the serial forced vital capacity monitoring that drives the airway decisionStepwise management with bedside spirometry, non-invasive ventilation versus intubation, rocuronium for rapid sequence induction, and cough augmentationMultidisciplinary care of the underlying cause, intensive weaning, rehabilitation, and the long-term ventilation decision in chronic diseaseCanadian approach to acute neuromuscular respiratory failure and acute flaccid paralysis surveillance, with serial forced vital capacity monitoring driving the intensive care and airway decisionNon-invasive ventilation when bulbar function is intact, intubation with rocuronium avoiding suxamethonium for bulbar weakness, and cough augmentation with mechanical insufflation-exsufflationCoordination of disease-specific therapy, intensive care, rehabilitation, and the family-centred long-term ventilation decision

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Red flags

Life stages

infanttoddlerpreschoolschool-ageadolescentyoung-adult-transition

Care settings

ed-acutewardpicuretrievalrural-remote

Clinical exam formats

written-only

Board mappings

A previously well seven-year-old who is recovering from a viral illness stops walking over three days. His legs are weak and floppy, his reflexes have vanished, and by day four he is struggling to finish a sentence and his cough is barely audible. His oxygen saturation reads ninety-eight percent. This child has a failing respiratory bellows, and if the team waits for the saturation to drop or the carbon dioxide to rise they will be intubating after an arrest rather than before one. The lungs are normal; the pump has failed. The whole art of managing acute neuromuscular respiratory failure is to recognise the failing pump early, measure it with a bedside forced vital capacity, and protect the airway before the blood gas decompensates. [4][1]

Overview & Definition

Acute neuromuscular respiratory failure is ventilatory failure caused by weakness of the respiratory pump, the chain that runs from the brainstem respiratory centre through the spinal cord and motor nerves to the neuromuscular junctions and the respiratory muscles, while the lung tissue itself is structurally normal. It is a bellows failure, not an alveolar failure. Because the failing pump moves less air, the defining physiological disturbance is progressive hypercapnia from under-ventilation, with a superimposed hypoxaemia once bulbar weakness lets secretions and feed pool and micro-aspirate. [4]

The clinical problem is that this failure is invisible to the monitors early on. The remaining alveoli still oxygenate the blood that reaches them, so the oxygen saturation stays high while carbon dioxide climbs; a normal saturation is therefore reassuring in the wrong direction. The single most important habit is to measure the respiratory reserve directly with a bedside forced vital capacity and to track it over time, because the trajectory of that number predicts arrest hours before the child looks sick. [1][3]

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References12Show ledger

[1]Lawn ND, Fletcher DD, Henderson RD, et al. Anticipating mechanical ventilation in Guillain-Barré syndrome Arch Neurol, 2001.PMID 11405803
[2]Durand MC, Porcher R, Orlikowski D, et al Clinical and electrophysiological predictors of respiratory failure in Guillain-Barré syndrome: a prospective study Lancet Neurol, 2006.PMID 17110282
[3]Sharshar T, Chevret S, Bourdain F, Raphaël JC Early predictors of mechanical ventilation in Guillain-Barré syndrome Crit Care Med, 2003.PMID 12545029
[4]Bach JR, Turcios NL, Wang L Respiratory Complications of Pediatric Neuromuscular Diseases Pediatr Clin North Am, 2021.PMID 33228931
[5]Birnkrant DJ, Bushby K, Bann CM, et al Diagnosis and management of Duchenne muscular dystrophy, part 2: respiratory, cardiac, bone health, and orthopaedic management Lancet Neurol, 2018.PMID 29395990
[6]Wang CH, Finkel RS, Bertini ES, et al Consensus statement for standard of care in spinal muscular atrophy J Child Neurol, 2007.PMID 17761659
[7]Pifko E, Price A, Sterner S Infant botulism and indications for administration of botulism immune globulin Pediatr Emerg Care, 2014.PMID 24488164
[8]Misra UK, Kumar S, Singh VK, et al Noninvasive Ventilation in Myasthenia Gravis Neurol India, 2020.PMID 32643679
[9]Wijdicks EF, Roy TK BiPAP in early guillain-barré syndrome may fail Can J Neurol Sci, 2006.PMID 16583732
[10]Martyn JA, Richtsfeld M Succinylcholine-induced hyperkalemia in acquired pathologic states: etiologic factors and molecular mechanisms Anesthesiology, 2006.PMID 16394702
[11]Bach JR, Choi WA Mechanical Insufflation-Exsufflation: The Rest of the Story Respiration, 2023.PMID 37040715
[12]Gonçalves MR, Bach JR, Ishikawa Y, et al Continuous noninvasive ventilatory support outcomes for patients with neuromuscular disease: a multicenter data collaboration Pulmonology, 2021.PMID 34656524

Acute neuromuscular respiratory failure

Also known as Neuromuscular ventilatory failure · Respiratory pump failure · Respiratory muscle failure · Ventilatory failure from neuromuscular weakness

high12 referencesUpdated 16 July 202616 min readVerification in progress

Practise this topic

Overview & Definition

Paediatrics Fellowship Pro

You have read the opening of this topic. The complete unit — every section and its primary-source references — is part of the Paediatrics Fellowship fellowship atlas.

References12Show ledger

[1]Lawn ND, Fletcher DD, Henderson RD, et al. Anticipating mechanical ventilation in Guillain-Barré syndrome Arch Neurol, 2001.PMID 11405803
[2]Durand MC, Porcher R, Orlikowski D, et al Clinical and electrophysiological predictors of respiratory failure in Guillain-Barré syndrome: a prospective study Lancet Neurol, 2006.PMID 17110282
[3]Sharshar T, Chevret S, Bourdain F, Raphaël JC Early predictors of mechanical ventilation in Guillain-Barré syndrome Crit Care Med, 2003.PMID 12545029
[4]Bach JR, Turcios NL, Wang L Respiratory Complications of Pediatric Neuromuscular Diseases Pediatr Clin North Am, 2021.PMID 33228931
[5]Birnkrant DJ, Bushby K, Bann CM, et al Diagnosis and management of Duchenne muscular dystrophy, part 2: respiratory, cardiac, bone health, and orthopaedic management Lancet Neurol, 2018.PMID 29395990
[6]Wang CH, Finkel RS, Bertini ES, et al Consensus statement for standard of care in spinal muscular atrophy J Child Neurol, 2007.PMID 17761659
[7]Pifko E, Price A, Sterner S Infant botulism and indications for administration of botulism immune globulin Pediatr Emerg Care, 2014.PMID 24488164
[8]Misra UK, Kumar S, Singh VK, et al Noninvasive Ventilation in Myasthenia Gravis Neurol India, 2020.PMID 32643679
[9]Wijdicks EF, Roy TK BiPAP in early guillain-barré syndrome may fail Can J Neurol Sci, 2006.PMID 16583732
[10]Martyn JA, Richtsfeld M Succinylcholine-induced hyperkalemia in acquired pathologic states: etiologic factors and molecular mechanisms Anesthesiology, 2006.PMID 16394702
[11]Bach JR, Choi WA Mechanical Insufflation-Exsufflation: The Rest of the Story Respiration, 2023.PMID 37040715
[12]Gonçalves MR, Bach JR, Ishikawa Y, et al Continuous noninvasive ventilatory support outcomes for patients with neuromuscular disease: a multicenter data collaboration Pulmonology, 2021.PMID 34656524