Breathing pattern adjustments during the first year following cervical spinal cord injury

Loveridge, B; Sanii, R.; Dubo, H.

doi:10.1038/sc.1992.102

Cited by 39 publications

(35 citation statements)

References 17 publications

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“…22,23 Our findings are in accordance with experimental data previously reported in unilateral C5 contusion 8 and bilateral cervical contusion 9,10 paradigms. Most of these studies demonstrated transient changes in respiratory rate and tidal volume under normoxic conditions, but no effects on global minute ventilation.…”

Section: Discussionsupporting

confidence: 83%

Early Phrenic Motor Neuron Loss and Transient Respiratory Abnormalities after Unilateral Cervical Spinal Cord Contusion

Nicaise

Frank

Hala

et al. 2013

Journal of Neurotrauma

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Contusion-type cervical spinal cord injury (SCI) is one of the most common forms of SCI observed in patients. In particular, injuries targeting the C3-C5 region affect the pool of phrenic motor neurons (PhMNs) that innervates the diaphragm, resulting in significant and often chronic respiratory dysfunction. Using a previously described rat model of unilateral midcervical C4 contusion with the Infinite Horizon Impactor, we have characterized the early time course of PhMN degeneration and consequent respiratory deficits following injury, as this knowledge is important for designing relevant treatment strategies targeting protection and plasticity of PhMN circuitry. PhMN loss (48% of the ipsilateral pool) occurred almost entirely during the first 24 h post-injury, resulting in persistent phrenic nerve axonal degeneration and denervation at the diaphragm neuromuscular junction (NMJ). Reduced diaphragm compound muscle action potential amplitudes following phrenic nerve stimulation were observed as early as the first day post-injury (30% of pre-injury maximum amplitude), with slow functional improvement over time that was associated with partial reinnervation at the diaphragm NMJ. Consistent with ipsilateral diaphragmatic compromise, the injury resulted in rapid, yet only transient, changes in overall ventilatory parameters measured via whole-body plethysmography, including increased respiratory rate, decreased tidal volume, and decreased peak inspiratory flow. Despite significant ipsilateral PhMN loss, the respiratory system has the capacity to quickly compensate for partially impaired hemidiaphragm function, suggesting that C4 hemicontusion in rats is a model of SCI that manifests subacute respiratory abnormalities. Collectively, these findings demonstrate significant and persistent diaphragm compromise in a clinically relevant model of midcervical contusion SCI; however, the therapeutic window for PhMN protection is restricted to early time points post-injury. On the contrary, preventing loss of innervation by PhMNs and/or inducing plasticity in spared PhMN axons at the diaphragm NMJ are relevant long-term targets.

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Section: Discussionsupporting

confidence: 83%

Early Phrenic Motor Neuron Loss and Transient Respiratory Abnormalities after Unilateral Cervical Spinal Cord Contusion

Nicaise

Frank

Hala

et al. 2013

Journal of Neurotrauma

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“…This improvement can be due to an increased elastic recoil of the lungs, resulting from a high FVC. The increase in MEP observed by other authors is related to specific expiratory muscle intervention, (4,9,29) which did not occur in our study, because the protocol was applied to the inspiratory muscles only.…”

Section: Resultsmentioning

confidence: 49%

“…According to one group of authors, (4) the tonus of the abdominal muscles increases by approximately 3 months after the lesion, and that, at one year after the injury, pulmonary function can improve in relation to the initial phase and tends to become stable. (3,28) In our study, none of the patients was in the acute phase, since the duration of the lesion ranged from 35 to 318 months, and, although there was no control group, spontaneous improvement is not probable in this phase.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, these patients are highly susceptible to inspiratory muscle fatigue and pulmonary complications. (4,5) Specific training in which inspiratory muscles are overloaded through the use of resistive or threshold inspiratory muscle trainers can improve MIP. When a resistive trainer is employed, the inspiratory load depends on the diameter of the orifice and the breathing pattern of the patient, thus not allowing constant loads to be achieved.…”

Section: Methodsmentioning

confidence: 99%

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Treinamento de músculos inspiratórios em pacientes com quadriplegia

et al. 2010

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Objective: To determine whether inspiratory muscle training can increase strength and endurance of these muscles in quadriplegic patients. Methods: Eight quadriplegic patients (7 males and 1 female) with injury to the lower cervical spine (segments C4-C7) were submitted to inspiratory muscle training with a threshold inspiratory muscle trainer adjusted to 30% of MIP. The training sessions were carried out with the patients in a sitting position, 5 days a week for 8 weeks. Endurance time, MIP, MEP and FVC were determined at baseline, week 4 and week 8. Results: In comparison with the mean baseline value, there was an increase in MIP, measured in the sitting position, at weeks 4 and 8 (−83.0 ± 18.9 cmH 2 O vs. −104.0 ± 19.4 cmH 2 O and −111.3 ± 22.7 cmH 2 O). There was an increase in MEP, also in the sitting position, at week 4 (from 36.8 ± 8.1 to 42.6 ± 8.8 cmH 2 O). There was an improvement in FVC at week 4 (from 2.1 ± 0.8 to 2.5 ± 0.6 L, representing an increase of 24 ± 22%). Although there was an increase in endurance (sitting) at week 8, the difference was not significant in comparison with the baseline value (29.8 ± 21.0 vs. 35.9 ± 15.5 min, an increase of 173 ± 233%). Conclusions: Quadriplegic patients can benefit from training at low loads (30% of MIP), which can improve inspiratory muscle strength, FVC and expiratory muscle performance.Keywords: Respiratory mechanics; Quadriplegia; Breathing exercises. ResumoObjetivo: Determinar se o treinamento de músculos inspiratórios pode aumentar a força e endurance desses músculos em pacientes com quadriplegia. Métodos: Oito pacientes quadriplégicos (7 homens e 1 mulher) com lesão medular cervical entre C4 e C7 foram submetidos ao treinamento de músculos inspiratórios utilizando-se um resistor de carga linear ajustado em 30% da PImáx. As sessões de treinamento foram realizadas com os pacientes sentados 5 vezes por semana por 8 semanas. Tempo de endurance, PImáx, PEmáx e CVF foram medidos antes do treinamento e nas semanas 4 e 8. Resultados: Em comparação ao valor basal médio, houve um aumento da PImáx, mensurada na posição sentada, nas semanas 4 e 8 (−83,0 ± 18,9 cmH 2 O vs. −104,0 ± 19,4 e −111,3 ± 22,7 cmH 2 O). Houve aumento da PEmáx, também na posição sentada, na semana 4 (de 36,8 ± 8,1 a 42,6 ± 8,8 cmH 2 O). Houve uma melhora na FVC na 4ª semana (de 2,1 ± 0,8 a 2,5 ± 0,6 L, representando um incremento de 24 ± 22%).O tempo de endurance (sentado) não apresentou um aumento significativo entre o momento basal e a semana 8 (29,8 ± 21,0 min vs. 35,9 ± 15,5 min; aumento de 173 ± 233%). Conclusões: Pacientes com quadriplegia podem se beneficiar com o treinamento com baixas cargas (30% da PImáx), com melhora da força dos músculos inspiratórios, CVF e efetividade dos músculos expiratórios.

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“…It is uncommon to find P Emax inferior to P Imax even if in some neurological diseases, such as cervical spinal cord injury, 59 P Emax is typically more reduced than P Imax . Different studies reported varying normal values for P Imax and P Emax that are lower in females and fall with advancing age with large SD values of the data, which mean that lower limits of normality are approximately 50% of predicted normal values.…”

Section: Airway Pressure and Flowmentioning

confidence: 99%

Ultrasonographic Assessment of Diaphragm Function in Critically Ill Subjects

Umbrello

Formenti

2016

Respir Care

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The majority of patients admitted to the ICU require mechanical ventilation as a part of their process of care. However, mechanical ventilation itself or the underlying disease can lead to dysfunction of the diaphragm, a condition that may contribute to the failure of weaning from mechanical ventilation. However, extended time on the ventilator increases health-care costs and greatly increases patient morbidity and mortality. Nevertheless, symptoms and signs of muscle disease in a bedridden (or bed rest-only) ICU patient are often difficult to assess because of concomitant confounding factors. Conventional assessment of diaphragm function lacks specific, noninvasive, time-saving, and easily performed bedside tools or requires patient cooperation. Recently, the use of ultrasound has raised great interest as a simple, noninvasive method of quantification of diaphragm contractile activity. In this review, we discuss the physiology and the relevant pathophysiology of diaphragm function, and we summarize the recent findings concerning the evaluation of its (dys)function in critically ill patients, with a special focus on the role of ultrasounds. We describe how to assess diaphragm excursion and diaphragm thickening during breathing and the meaning of these measurements under spontaneous or mechanical ventilation as well as the reference values in health and disease. The spread of ultrasonographic assessment of diaphragm function may possibly result in timely identification of patients with diaphragm dysfunction and to a potential improvement in the assessment of recovery from diaphragm weakness.

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Breathing pattern adjustments during the first year following cervical spinal cord injury

Cited by 39 publications

References 17 publications

Early Phrenic Motor Neuron Loss and Transient Respiratory Abnormalities after Unilateral Cervical Spinal Cord Contusion

Early Phrenic Motor Neuron Loss and Transient Respiratory Abnormalities after Unilateral Cervical Spinal Cord Contusion

Treinamento de músculos inspiratórios em pacientes com quadriplegia

Ultrasonographic Assessment of Diaphragm Function in Critically Ill Subjects

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