Although ventilatory failure is the most common cause of death in amyotrophic lateral sclerosis (ALS) and measurement of respiratory muscle strength (RMS) has been shown to have prognostic value, no single test of strength can predict the presence of hypercapnia reliably. RMS was measured in 81 ALS patients to evaluate the relationship between tests of RMS and the presence of ventilatory failure, defined as a carbon dioxide tension > or = 6 kPa. We studied the predictive value of vital capacity (VC), static inspiratory and expiratory mouth pressures (MIP, MEP), maximal sniff oesophageal (sniff P(oes)), transdiaphragmatic (sniff P(di)) and nasal (SNP) pressure, cough gastric (cough P(gas)) pressure and transdiaphragmatic pressure after bilateral cervical magnetic phrenic nerve stimulation (CMS P(di)) to identify the risk of ventilatory failure in the whole group and in subgroups of patients with and without significant bulbar involvement. For patients without significant bulbar involvement, sniff P(di) had greatest predictive power [odds ratio (OR) 57] with specificity, sensitivity and positive and negative predictive values (PPV, NPV) of 87, 90, 74 and 95%, respectively Of the less invasive tests, per cent predicted SNP had greater overall predictive power (OR 25, specificity 85%, sensitivity 81%) than per cent predicted VC (9, 89%, 53%) and per cent predicted MIP (6, 83%, 55%). No test had significant predictive power for the presence of hypercapnia when used to measure RMS in a subgroup of patients with significant bulbar weakness. Thirty-five patients underwent polysomnography. CMS P(di), sniff P(di) and per cent predicted SNP were significantly correlated with the apnoea/hypopnoea index (AHI) (P = 0.035, 0.042 and 0.026, respectively). The correlations between AHI and per cent predicted MIP and VC were less strong (both non-significant). In ALS patients without significant bulbar involvement, novel tests of RMS have greater predictive power than conventional tests to predict hypercapnia. In particular, the non-invasive SNP is more sensitive than VC and MIP, suggesting that it could usefully be included in tests of respiratory muscle strength in ALS and will be helpful in assessing the risk of ventilatory failure. In patients with significant bulbar involvement, tests of respiratory muscle strength do not predict hypercapnia. Sleep-disordered breathing is correlated with RMS and the novel tests of RMS having the strongest relationship with the degree of sleep disturbance.

BackgroundA standardised approach to assessing COVID-19 survivors has not been established, largely due to the paucity of data on medium- and long-term sequelae. Interval chest radiograph is recommended following community-acquired pneumonia, however its utility in monitoring recovery from COVID-19 pneumonia remains unclear.MethodsProspective single-centre observational cohort study. Patients hospitalised with severe COVID-19 pneumonia (admission duration ≥48 h and oxygen requirement ≥40% or critical care admission) underwent face-to-face assessment 4–6 weeks post-discharge. Primary outcome: radiological resolution of COVID-19 pneumonitis (Radiographic Assessment of Lung Oedema score <5). Secondary outcomes: clinical outcomes, symptom questionnaires, mental health screening (Trauma Screening Questionnaire, GAD-7, PHQ-9), physiological testing (4-metre gait speed (4MGS), 1-minute sit-to-stand test (STS)).Results119 patients assessed between 3rd June and 2nd July 2020 at median (IQR) 61 (51–67) days post-discharge. Mean±sd age 58.7±14.4 years, body mass index 30.0 (25.9–35.2) kg·m−2, 62% male, 68% ethnic minority. Despite radiographic resolution of pulmonary infiltrates in 87%, mMRC breathlessness scores were above pre-COVID baseline in 46% and patients reported persistent fatigue (68%), sleep disturbance (57%) and breathlessness (32%). Screening thresholds were breached for post-traumatic stress disorder (25%), anxiety (22%) and depression (18%). 4MGS was slow (<0.8 m·s−1) in 38%, 35% desaturated by ≥4% during STS. Of 56 thoracic computed tomography scans performed, 75% demonstrated COVID-related interstitial and/or airways disease.ConclusionsPersistent symptoms, adverse mental health outcomes and physiological impairment are common 2 months after severe COVID-19 pneumonia. Follow-up chest radiograph is a poor marker of recovery, therefore holistic face-to-face assessment is recommended to facilitate early recognition and management of post-COVID sequelae.

Noninvasive positive pressure ventilation prolongs survival in ALS but its effect on quality of life is unknown. The authors prospectively studied quality of life using the SF-36 questionnaire in a cohort of 16 ventilated patients with ALS. Noninvasive positive pressure ventilation improved scores in the "Vitality" domain by as much as 25%, for periods of up to 15 months, despite disease progression. Noninvasive positive pressure ventilation did not cause reduced quality of life, as any fall in scores in the ventilated group were comparable to those seen in a control group. In conclusion, noninvasive positive pressure ventilation enhances quality of life when used to treat sleep-disordered breathing in patients with ALS.

Few data exist concerning expiratory muscle function in amyotrophic lateral sclerosis (ALS). We studied 26 patients with ALS (16 with respiratory symptoms and 10 without) and measured the maximal static expiratory mouth pressure (MEP), the gastric pressure during a maximal cough (Cough Pga), and the gastric pressure after magnetic stimulation of the lower thoracic nerve roots (Tw Pga). These measurements were related to the ability to generate transient supramaximal flow during a cough (cough spikes), to arterialized capillary blood gases, and to inspiratory muscle strength. Vocal cord motion was examined endoscopically in 11 of the 16 symptomatic patients. Expiratory muscle weakness was related to inability to generate cough spikes with a threshold effect such that spikes were absent for Cough Pga < 50 cm H2O (p = 0.009) or Tw Pga < 7 cm H2O (p = 0.006) and was usually associated with inspiratory muscle weakness. However, in multivariate analysis, PaCO2 was only significantly associated with the maximal sniff esophageal pressure (p = 0.02). Symptomatic patients had significantly lower inspiratory muscle strength, whereas, of the expiratory muscle tests, only Tw Pga was significantly lower (p = 0.0009) in symptomatic patients. Abnormal vocal cord motion was observed in two of the 11 patients examined. We conclude that abdominal muscle weakness in ALS, when substantial, results in an inability to generate transient supramaximal flow during a cough. However, the primary determinant of both ventilatory failure and respiratory symptoms seems to be inspiratory muscle weakness.