Douglas McKim

Home mechanical ventilation: a Canadian Thoracic Society clinical practice guideline.

Increasing numbers of patients are surviving episodes of prolonged mechanical ventilation or benefitting from the recent availability of userfriendly noninvasive ventilators. Although many publications pertaining to specific aspects of home mechanical ventilation (HMV) exist, very few comprehensive guidelines that bring together all of the current literature on patients at risk for or using mechanical ventilatory support are available. The Canadian Thoracic Society HMV Guideline Committee has reviewed the available English literature on topics related to HMV in adults, and completed a detailed guideline that will help standardize and improve the assessment and management of individuals requiring noninvasive or invasive HMV. The guideline provides a disease-specific review of illnesses including amyotrophic lateral sclerosis, spinal cord injury, muscular dystrophies, myotonic dystrophy, kyphoscoliosis, post-polio syndrome, central hypoventilation syndrome, obesity hypoventilation syndrome, and chronic obstructive pulmonary disease as well as important common themes such as airway clearance and the process of transition to home. The guidelines have been extensively reviewed by international experts, allied health professionals and target audiences. They will be updated on a regular basis to incorporate any new information.

A randomised trial to evaluate the self-administered standardised chronic respiratory questionnaire

The original chronic respiratory questionnaire (CRQ), one of the most widely used measures of health-related quality of life (HRQL) in chronic respiratory disease (CRD), is traditionally interviewer administered (IA) and includes an individualised dyspnoea domain. The present authors studied the impact of self-administered (SA) and standardised dyspnoea questions on CRQ measurement properties. In a factorial design multicentre trial, 177 patients with CRD (mean age 67.7 yrs; mean forced expiratory volume in one second per cent predicted 44.6%) were randomised to CRQ-IA (n = 86) or CRQ-SA (n = 91), and to initially complete the standardised or individualised items before and after respiratory rehabilitation. While maintaining validity, the CRQ-SA proved more responsive to changes in HRQL than the CRQ-IA in all domains. Compared with the standardised dyspnoea domain, the individualised dyspnoea domain indicated greater responsiveness. The correlations of baseline scores and change scores with other HRQL instruments indicated good validity of the CRQ-SA. In conclusion, self-administration and standardisation of the chronic respiratory questionnaire maintains validity and responsiveness relative to the interviewer-administered chronic respiratory questionnaire. These results challenge the assumption that interviewer-administered questionnaires are superior to self-administered questionnaires in older patients with chronic respiratory disease.

Lung volume recruitment slows pulmonary function decline in Duchenne muscular dystrophy.

OBJECTIVE To evaluate the long-term effect on measures of forced vital capacity (FVC) before and after the introduction of regular lung volume recruitment (LVR) maneuvers (breath-stacking) in individuals with Duchenne muscular dystrophy (DMD). DESIGN Retrospective cohort study of pulmonary function data, including FVC, cough peak flow (CPF), maximum inspiratory pressure (MIP), and maximum expiratory pressure (MEP). Data were collected for 33 months prior to and 45 months after LVR introduction. SETTING Ambulatory care in a tertiary level regional rehabilitation center in Canada. PARTICIPANTS All individuals (N=22) with DMD (mean age ± SD, 19.6±2.4y), who were prescribed LVR and reported adherence with therapy. INTERVENTIONS Introduction of regular LVR (breath-stacking); 3 to 5 maximal lung inflations (maximum insufflation capacity [MIC]) using a hand-held resuscitation bag and mouthpiece, twice daily. MAIN OUTCOME MEASURES Measures included the rate of decline of FVC in percent-predicted, before and after the introduction of regular LVR. Changes in maximum pressures (MIP, MEP), MIC, and cough peak flows were also measured. RESULTS At LVR initiation, FVC was 21.8±16.9 percent-predicted, and cough peak flows were <270L/min (144.8±106.9L/min). Annual decline of FVC was 4.7 percent-predicted a year before LVR and 0.5 percent-predicted a year after LVR initiation. The difference, 4.2 percent-predicted a year (95% confidence interval, 3.5-4.9; P<.000), represents an 89% improvement in the annual rate of FVC decline. CONCLUSIONS The rate of FVC decline in DMD patients improves dramatically with initiation of regular LVR.

Home Mechanical Ventilation in Canada: A National Survey

BACKGROUND: No comprehensive Canadian national data describe the prevalence of and service provision for ventilator-assisted individuals living at home, data critical to health-care system planning for appropriate resourcing. Our objective was to generate national data profiling service providers, users, types of services, criteria for initiation and monitoring, ventilator servicing arrangements, education, and barriers to home transition. METHODS: Eligible providers delivering services to ventilator-assisted individuals (adult and pediatric) living at home were identified by our national provider inventory and referrals from other providers. The survey was administered via a web link from August 2012 to April 2013. RESULTS: The survey response rate was 152/171 (89%). We identified 4,334 ventilator-assisted individuals: an estimated prevalence of 12.9/100,000 population, with 73% receiving noninvasive ventilation (NIV) and 18% receiving intermittent mandatory ventilation (9% not reported). Services were delivered by 39 institutional providers and 113 community providers. We identified variation in initiation criteria for NIV, with polysomnography demonstrating nocturnal hypoventilation (57%), daytime hypercapnia (38%), and nocturnal hypercapnia (32%) as the most common criteria. Various models of ventilator servicing were reported. Most providers (64%) stated that caregiver competency was a prerequisite for home discharge; however, repeated competency assessment and retraining were offered by only 45%. Important barriers to home transition were: insufficient funding for paid caregivers, equipment, and supplies; a shortage of paid caregivers; and negotiating public funding arrangements. CONCLUSIONS: Ventilatory support in the community appears well-established, with most individuals managed with NIV. Although caregiver competency is a prerequisite to discharge, ongoing assessment and retraining were infrequent. Funding and caregiver availability were important barriers to home transition.

Formal ventilation patient education for ALS predicts real-life choices

Abstract Our objective was to evaluate a single-session, hands-on education programme on mechanical ventilation for ALS patients and caregivers in terms of knowledge, change in affect and to determine whether ventilator decisions made after the education sessions predict those made later in life. Questionnaires were administered to 26 patients and 26 caregivers on four separate occasions. The questionnaires assessed knowledge of ventilatory support, feedback on the nature of the education programme, as well as self-reported emotional well-being. All patients were followed until their death or until initiation of invasive ventilation. Both groups demonstrated significant improvements in knowledge as a result of the education session which was retained after one month. There was no change in patient or caregiver reports’ self-reported emotional well-being. The choices of ventilatory support expressed at one month (T4) accurately predicted the real-life clinical choices made by 76% of patients. Any difference resulted from choosing palliative care. Hands-on patient and caregiver education results in improved knowledge, assists in decision-making with respect to ventilatory support, and is not associated with a worsening of affect. It also provides for an accurate prediction of real-life choices and avoids undesired life support interventions and critical care admissions.

Respiratory management strategies for Duchenne muscular dystrophy: practice variation amongst canadian sub-specialists†

Respiratory management of Duchenne muscular dystrophy (DMD) is not well studied and may vary across centers and practitioners. Our objective was to describe and compare the respiratory management practices of Canadian Pediatric Respirologists and Neuromuscular specialists for children with DMD.

Do clinical marker states improve responsiveness and construct validity of the standard gamble and feeling thermometer: A randomized multi-center trial in patients with chronic respiratory disease

Background: Optimizing the validity and responsiveness of utility measures will enhance their usefulness in randomized trials. We evaluated the impact of clinical marker state (CMS) rating prior to patients’ rating their own health on two utility instruments (feeling thermometer (FT) and standard gamble (SG)) in patients with chronic respiratory disease (CRD). Methods: We randomized 182 patients with CRD to complete the FT (self-administered) and SG with CMS (FT+/SG+, n=91) or without marker states (FT−/SG−, n=91) before and after undergoing respiratory rehabilitation in a multi-center trial. Results: Use of CMS did not influence baseline utility scores. Improvement after therapy on the scale from 0 (dead) to 1.0 (full health) was 0.04 both in FT+ (p=0.03) and FT− (p=0.02; the difference between FT+ and FT− was 0.00, p=0.83). Improvement on the SG was 0.05 in both SG+ (p=0.08) and SG− (p=0.04; difference between SG+ and SG− 0.00, p=0.95). Correlations with other health related quality of life scores were highest for FT+. Conclusion: Administration of CMS did not improve responsiveness of the FT but may have improved construct validity. The SG showed limited construct validity and responsiveness that was not influenced by CMS use.

Lung Volume Recruitment in Multiple Sclerosis

Introduction Pulmonary function abnormalities have been described in multiple sclerosis including reductions in forced vital capacity (FVC) and cough but the time course of this impairment is unknown. Peak cough flow (PCF) is an important parameter for patients with respiratory muscle weakness and a reduced PCF has a direct impact on airway clearance and may therefore increase the risk of respiratory tract infections. Lung volume recruitment is a technique that improves PCF by inflating the lungs to their maximal insufflation capacity. Objectives Our goals were to describe the rate of decline of pulmonary function and PCF in patients with multiple sclerosis and describe the use of lung volume recruitment in this population. Methods We reviewed all patients with multiple sclerosis referred to a respiratory neuromuscular rehabilitation clinic from February 1999 until December 2010. Lung volume recruitment was attempted in patients with FVC <80% predicted. Regular twice daily lung volume recruitment was prescribed if it resulted in a significant improvement in the laboratory. Results There were 79 patients included, 35 of whom were seen more than once. A baseline FVC <80% predicted was present in 82% of patients and 80% of patients had a PCF insufficient for airway clearance. There was a significant decline in FVC (122.6 mL/y, 95% CI 54.9–190.3) and PCF (192 mL/s/y, 95% 72–311) over a median follow-up time of 13.4 months. Lung volume recruitment was associated with a slower decline in FVC (p<0.0001) and PCF (p = 0.042). Conclusion Pulmonary function and cough decline significantly over time in selected patients with multiple sclerosis and lung volume recruitment is associated with a slower rate of decline in lung function and peak cough flow. Given design limitations, additional studies are needed to assess the role of lung volume recruitment in patients with multiple sclerosis.

A Breathlessness Catastrophizing Scale for chronic obstructive pulmonary disease

OBJECTIVE Catastrophizing about breathlessness may be related to disability in patients with chronic obstructive pulmonary disease (COPD), but assessment options are limited. This study reports the initial validation of a 13-item Breathlessness Catastrophizing Scale (BCS). METHOD Pulmonary rehabilitation inpatients completed spirometric, functional performance and questionnaire assessments at admission (N=242) and discharge (n=186). RESULTS The BCS comprised a unifactorial scale that demonstrated excellent internal consistency (Cronbachs alpha=.96) and correlated with measures of anxiety sensitivity, depression, and self-efficacy, but not with performance on walk and stair-climbing tests. BCS scores improved robustly with rehabilitation, approaching a medium effect size (d=.43), and demonstrated a modest association with enhanced performance in a stair-climbing test of exercise tolerance. CONCLUSION The BCS is a reliable measure of catastrophizing in severe COPD that has good convergent validity and sensitivity to change. Its association with functional performance requires further investigation. However, it appears that a high level of catastrophizing about breathlessness is not a barrier to functional improvement with inpatient pulmonary rehabilitation.

Tracheostomy Decannulation and Cough Peak Flows in Patients with Neuromuscular Weakness

ObjectiveThe aim of this study was to examine the relationship between cough peak flows (CPFs) before and after tracheostomy tube removal (decannulation) in patients with neuromuscular respiratory muscle weakness. DesignFor 26 patients with occluded tracheostomies (capped or Passy-Muir valve), spontaneous CPF (CPFsp), CPF after lung volume recruitment (CPFLVR), and CPF after lung volume recruitment and a manually assisted cough (CPFLVR + MAC) were measured before and after decannulation. ResultsDecannulation resulted in a significant increase (P < 0.001) in CPF of 35.6, 34.5, and 42.6 l/min for CPFsp, CPFLVR, and CPFLVR + MAC, respectively. In addition, CPFLVR or CPFLVR + MAC with a capped tracheostomy in place were greater than spontaneous CPF with the tracheostomy tube removed. ConclusionsOur study suggests that assisted coughing with a capped tracheostomy tube in place can result in higher flows than removing the tube and relying on spontaneous cough alone. Postdecannulation CPF measured at the mouth can be predicted to be at least 34.5 l/min greater than predecannulation values, which may thereby lower the threshold of the CPF indicated for safe decannulation.