Home mechanical ventilatory support in patients with restrictive ventilatory disorders: A 48-year experience

Does PaCO2 correction have an impact on survival of patients with chronic respiratory failure and long-term non-invasive ventilation?

Background and objective

Non-invasive ventilation (NIV) improves survival of patients with chronic respiratory failure (CRF). Most often, pressure settings are made to normalize arterial blood gases. However, this objective is not always achieved due to intolerance to increased pressure or poor compliance. Few studies have assessed the effect of persistent hypercapnia on ventilated patients' survival. Data from the Pays de la Loire Respiratory Health Research Institute cohort were analyzed to answer this question.

Study design and methods

NIV-treated adults enrolled between 2009 and 2019 were divided into 5 subgroups: obesity-hypoventilation syndrome (OHS), COPD, obese COPD, neuromuscular disease (NMD) and chest wall disease (CWD). PaCO2 correction was defined as the achievement of a PaCO2 < 6 kPa or a 20% decrease in baseline PaCO₂ in COPD patients. The endpoint was all-cause mortality. Follow-up was censored in case of NIV discontinuation.

Results

Data from 431 patients were analyzed. Median survival was 103 months and 148 patients died. Overall, PaCO2 correction was achieved in 74% of patients. Bivariate analysis did not show any survival difference between patients who achievedPaCO₂ correction and those who remained hypercapnic: overall population: p = 0.74; COPD: p = 0.97; obese COPD: p = 0.28; OHS: p = 0.93; NMD: p = 0.84; CWD: p = 0.28.

Conclusion

Moderate residual hypercapnia under NIV does not negatively impact survival in CRF patients. In individuals with poor tolerance of pressure increases, residual hypercapnia can therefore be tolerated under long-term NIV. Larger studies, especially with a higher number of patients with residual PaCO2 > 7 kPa, are needed to confirm these results.

Combined high flow nasal cannula and negative pressure ventilation as a novel respiratory approach in a patient with acute respiratory failure and limb-girdle muscular dystrophy

We describe the case of a 56-year-old-man with limb-girdle muscular dystrophy affected by acute hypercapnic failure secondary to pneumonia treated with high flow nasal cannula, intermittent abdominal ventilation, and negative pressure ventilation. The patient did not tolerate noninvasive positive pressure ventilation and refused invasive ventilation and tracheostomy. We successfully experienced a novel approach combining high flow nasal cannula with cycles of intermittent abdominal pressure ventilation and negative pressure ventilation.

Long-Term Non-invasive Ventilation: Do Patients Aged Over 75 Years Differ From Younger Adults?

Background: Noninvasive ventilation (NIV) is accepted as standard of care for chronic hypercapnic respiratory failure (CHRF) and is being increasingly implemented in older subjects. However, little is known regarding the use of NIV on a long-term basis in the very old. The outcomes of this study were: 1/to report the proportion of patients ≥ 75 years old (elderly) among a large group of long-term NIV users and its trend since 2000; 2/to compare this population to a younger population (<75 years old) under long-term NIV in terms of diagnoses, comorbidities, anthropometric data, technical aspects, adherence to and efficiency of NIV.

Methods: In a cross-sectional analysis of a multicenter cohort study on patients with CHRF under NIV, diagnoses, comorbidities, technical aspects, adherence to and efficiency of NIV were compared between patients ≥ 75 and <75 years old (chi-square or Welch Student tests).

Results: Of a total of 489 patients under NIV, 151 patients (31%) were ≥ 75 years of age. Comorbidities such as systemic hypertension (86 vs. 60%, p < 0.001), chronic heart failure (30 vs. 18%, p = 0.005), and pulmonary hypertension (25 vs. 14%, p = 0.005) were more frequent in older subjects. In the older group, there was a trend for a higher prevalence of chronic obstructive pulmonary disease (COPD) (46 vs. 36%, p = 0.151) and a lower prevalence of neuromuscular diseases (NMD) (19 vs. 11%, p = 0.151), although not significant. Adherence to and efficacy of NIV were similar in both groups (daily use of ventilator: 437 vs. 419 min, p = 0.76; PaCO₂: 5.8 vs. 5.9 kPa, p = 0.968). Unintentional leaks were slightly higher in the older group (1.8 vs. 0.6 L/min, p = 0.018).

Conclusions: In this cross-sectional study, one third of the population under NIV was ≥ 75 years old. Markers of efficacy of NIV, and adherence to treatment were similar when compared to younger subjects, confirming the feasibility of long-term NIV in the very old. Health-related quality of life was not assessed in this study and further research is needed to address this issue.

Sleep in chronic respiratory disease: COPD and hypoventilation disorders

COPD and obstructive sleep apnoea (OSA) are highly prevalent and different clinical COPD phenotypes that influence the likelihood of comorbid OSA. The increased lung volumes and low body mass index (BMI) associated with the predominant emphysema phenotype protects against OSA whereas the peripheral oedema and higher BMI often associated with the predominant chronic bronchitis phenotype promote OSA. The diagnosis of OSA in COPD patients requires clinical awareness and screening questionnaires which may help identify patients for overnight study. Management of OSA-COPD overlap patients differs from COPD alone and the survival of overlap patients treated with nocturnal positive airway pressure is superior to those untreated. Sleep-related hypoventilation is common in neuromuscular disease and skeletal disorders because of the effects of normal sleep on ventilation and additional challenges imposed by the underlying disorders. Hypoventilation is first seen during rapid eye movement (REM) sleep before progressing to involve non-REM sleep and wakefulness. Clinical presentation is nonspecific and daytime respiratory function measures poorly predict nocturnal hypoventilation. Monitoring of respiration and carbon dioxide levels during sleep should be incorporated in the evaluation of high-risk patient populations and treatment with noninvasive ventilation improves outcomes.

National survey: current prevalence and characteristics of home mechanical ventilation in Hungary

BACKGROUND

Home mechanical ventilation is an established treatment for chronic respiratory failure resulting in improved survival and quality of life. Technological advancement, evolving health care reimbursement systems and newly implemented national guidelines result in increased utilization worldwide. Prevalence shows great geographical variations and data on East-Central European practice has been scarce to date. The aim of the current study was to evaluate prevalence and characteristics of home mechanical ventilation in Hungary.

METHODS

We conducted a nationwide study using an online survey focusing on patients receiving ventilatory support at home. The survey focused on characterization of the site (affiliation, type), experience with home mechanical ventilation, number of patients treated, indication for home mechanical ventilation (disease type), description of home mechanical ventilation (invasive/noninvasive, ventilation hours, duration of ventilation) and description of the care provided (type of follow up visits, hospitalization need, reimbursement).

RESULTS

Our survey uncovered a total of 384 patients amounting to a prevalence of 3.9/100,000 in Hungary. 10.4% of patients received invasive, while 89.6% received noninvasive ventilation. The most frequent diagnosis was central hypopnea syndromes (60%), while pulmonary (20%), neuromuscular (11%) and chest wall disorders (7%) were less frequent indications. Daily ventilation need was less than 8 h in 74.2%, between 8 and 16 h in 15.4% and more than 16 h in 10.4% of patients reported. When comparing sites with a limited (< 50 patients) versus substantial (> 50 patients) case number, we found the former had significantly higher ratio of neuromuscular conditions, were more likely to ventilate invasively, with more than 16 h/day ventilation need and were more likely to provide home visits and readmit patients (p < 0,001).

CONCLUSIONS

Our results show a reasonable current estimate and characterization of home mechanical ventilation practice in Hungary. Although a growing practice can be assumed, current prevalence is still markedly reduced compared to international data reported, the duality of current data hinting to a possible gap in diagnosis and care for more dependent patients. This points to the importance of establishing home mechanical ventilation centers, where increased experience will enable state of the art care to more dependent patients as well, increasing overall prevalence.

Definition, discrimination, diagnosis and treatment of central breathing disturbances during sleep

The complexity of central breathing disturbances during sleep has become increasingly obvious. They present as central sleep apnoeas (CSAs) and hypopnoeas, periodic breathing with apnoeas, or irregular breathing in patients with cardiovascular, other internal or neurological disorders, and can emerge under positive airway pressure treatment or opioid use, or at high altitude. As yet, there is insufficient knowledge on the clinical features, pathophysiological background and consecutive algorithms for stepped-care treatment. Most recently, it has been discussed intensively if CSA in heart failure is a “marker” of disease severity or a “mediator” of disease progression, and if and which type of positive airway pressure therapy is indicated. In addition, disturbances of respiratory drive or the translation of central impulses may result in hypoventilation, associated with cerebral or neuromuscular diseases, or severe diseases of lung or thorax. These statements report the results of an European Respiratory Society Task Force addressing actual diagnostic and therapeutic standards. The statements are based on a systematic review of the literature and a systematic two-step decision process. Although the Task Force does not make recommendations, it describes its current practice of treatment of CSA in heart failure and hypoventilation.

Long-Term Mechanical Ventilation

Although precise numbers are difficult to obtain, the population of patients receiving long-term ventilation has increased over the last 20 years, and includes patients with chronic lung diseases, neuromuscular diseases, spinal cord injury, and children with complex disorders. This article reviews the equipment and logistics involved with ventilation outside of the hospital. Discussed are common locations for long-term ventilation, airway and secretion management, and many of the potential challenges faced by individuals on long-term ventilation.

Complementary home mechanical ventilation techniques. SEPAR Year 2014

This is a review of the different complementary techniques that are useful for optimizing home mechanical ventilation (HMV). Airway clearance is very important in patients with HMV and many patients, particularly those with reduced peak cough flow, require airway clearance (manual or assisted) or assisted cough techniques (manual or mechanical) and suctioning procedures, in addition to ventilation. In the case of invasive HMV, good tracheostomy cannula management is essential for success. HMV patients may have sleep disturbances that must be taken into account. Sleep studies including complete polysomnography or respiratory polygraphy are helpful for identifying patient-ventilator asynchrony. Other techniques, such as bronchoscopy or nutritional support, may be required in patients on HMV, particularly if percutaneous gastrostomy is required. Information on treatment efficacy can be obtained from HMV monitoring, using methods such as pulse oximetry, capnography or the internal programs of the ventilators themselves. Finally, the importance of the patient's subjective perception is reviewed, as this may potentially affect the success of the HMV.

Respiratory diseases and muscle dysfunction

Many respiratory diseases lead to impaired function of skeletal muscles, influencing quality of life and patient survival. Dysfunction of both respiratory and limb muscles in chronic obstructive pulmonary disease has been studied in depth, and seems to be caused by the complex interaction of general (inflammation, impaired gas exchange, malnutrition, comorbidity, drugs) and local factors (changes in respiratory mechanics and muscle activity, and molecular events). Some of these factors are also present in cystic fibrosis and asthma. In obstructive sleep apnea syndrome, repeated exposure to hypoxia and the absence of reparative rest are believed to be the main causes of muscle dysfunction. Deconditioning appears to be crucial for the functional impairment observed in scoliosis. Finally, cachexia seems to be the main mechanism of muscle dysfunction in advanced lung cancer. A multidimensional therapeutic approach is recommended, including pulmonary rehabilitation, an adequate level of physical activity, ventilatory support and nutritional interventions.

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.

Predictors of mortality in chest wall disease treated with noninvasive home mechanical ventilation

RATIONALE

The long-term evolution of patients with chest wall disease and chronic respiratory failure treated with noninvasive home mechanical ventilation (NIHMV) is poorly known.

OBJECTIVES

The aim of this prospective observational study was to analyze the variables associated with mortality in a cohort of chest wall disease patients with chronic respiratory failure undergoing long-term follow-up after starting treatment with NIHMV.

METHODS

Chest wall disease patients who began NIHMV between 1996 and 2005 were followed up, with death as the primary outcome. The patients' clinical characteristics, lung function, and arterial blood gases were recorded at the start of treatment. Patients were seen and evaluated 1 month after starting NIHMV. The prognostic value of clinical and functional variables were assessed by Cox regression analyses.

MAIN RESULTS

We included 110 patients, 61 with tuberculosis sequelae and 49 with kyphoscoliosis. By the end of follow-up, 34 patients (28%) had died. The 5-year survival was 69% in those with tuberculosis sequelae and 75% in kyphoscoliosis. PaCO(2) ≥50 mmHg at 1 month of home ventilation and comorbidity (Charlson Index ≥3) were independent predictors of mortality.

CONCLUSION

Our results suggest that PaCO2 levels ≥50 mmHg at 1 month after starting noninvasive home mechanical ventilation and the presence of comorbid conditions are risk factors for mortality in patients with chest wall disease. The importance of early detection of suboptimal home ventilation as well as comorbidities is highlighted.

Validation of a transcutaneous CO(2) monitor in adult patients with chronic respiratory failure

BACKGROUND

Home mechanical ventilation is usually started in hospital as arterial blood gas sampling is deemed necessary to monitor CO(2) and O(2) adequately during institution of ventilatory support. A non-invasive device to reliably measure CO(2) transcutaneously would alleviate the need for high care settings for measurement and open the possibility for home registration.

OBJECTIVES

In this study we investigated whether the TOSCA® transcutaneous CO(2) (PtcCO(2)) measurements, performed continuously during the night, reliably reflect arterial CO(2) (PaCO(2)) measurements in adults with chronic respiratory failure.

METHODS

Paired measurements were taken in 15 patients hospitalised to evaluate their blood gas exchange. Outcomes were compared 30 min, 2, 4, 6 and 8 h after attaching the sensor to the earlobe. A maximum difference of 1.0 kPa and 95% limits of agreement (LOA) of 1 kPa between CO(2) pressure measurements, following the analysis by Bland and Altman, were determined as acceptable.

RESULTS

Mean PtcCO(2) was 0.4 kPa higher (LOA -0.48 to 1.27 kPa) than mean PaCO(2) after 30 min. These figures were 0.6 kPa higher (LOA -0.60 to 1.80 kPa) after 4 h, with a maximum of 0.72 kPa (LOA 0.35 to 1.79 kPa) after 8 h. The corresponding values for changes in PtcCO(2) versus PaCO(2) were not significant (ANOVA).

CONCLUSIONS

PtcCO(2) measurement, using TOSCA, is a valid method showing an acceptable agreement with PaCO(2) during 8 h of continuous measurement. Therefore, this device can be used to monitor CO(2) adequately during chronic ventilatory support.

Importance of the PaCO(2) from 3 to 6 months after initiation of long-term non-invasive ventilation

BACKGROUND

The level at which arterial carbon dioxide tension (PaCO(2)) a few months after introduction of long-term non-invasive positive pressure ventilation (NPPV) is associated with a favorable prognosis remains uncertain.

METHODS

Data on 184 post-tuberculosis patients with chronic restrictive ventilatory failure who were receiving long-term domiciliary NPPV were examined retrospectively. Average PaCO(2) 3-6 months after NPPV (3- to 6-mo PaCO(2)) and potential confounders were analyzed with discontinuation of long-term NPPV as the primary outcome. The effects of 3- to 6-mo PaCO(2) on annual hospitalization rates due to respiratory deterioration from 1 year before to 3 years after the initiation of NPPV were examined. The effect of the difference between the PaCO(2) value at the start of NPPV (0-mo PaCO(2)) and the PaCO(2) value 3- to 6-mo later (d-PaCO(2)) on continuation rates for NPPV was also assessed in patients who initiated NPPV while in a chronic state.

RESULTS

Patients with relatively low 3- to 6-mo PaCO(2) values maintained a relatively low PaCO(2) 6-36 months after NPPV (p < 0.0001) and had significantly better continuation rates (p < 0.03) and lower hospitalization rates from the 1st to 3rd year of NPPV (p = 0.008, 0.049, 0.009, respectively) than those with higher levels. The 0-mo PaCO(2) (p = 0.26) or d-PaCO(2) (p = 0.86) had no predictive value.

CONCLUSION

A relatively low 3- to 6-mo PaCO(2) value was predictive of long-term use of NPPV. The target values for 3- to 6-mo PaCO(2) may, therefore, be less than 60 mmHg in post-tuberculosis patients, although more studies are needed.

Predictors of long-term survival in patients with restrictive thoracic disorders and chronic respiratory failure undergoing non-invasive home ventilation

BACKGROUND AND OBJECTIVES

Non-invasive positive pressure ventilation (NPPV) is an established treatment in restrictive thoracic disorders (RTD) with chronic hypercapnic respiratory failure. The aim of this study was to identify predictors of long-term survival for patients on NPPV therapy.

METHODS

In a 10-year retrospective cohort of patients with RTD and chronic hypercapnic respiratory failure, survival and the predictive value of nocturnal and daytime blood gases, lung function and laboratory data measured before initiation of NPPV were assessed. The impact of ventilator settings and daily use of NPPV on survival were also evaluated. Patients were re-admitted every 6 months for follow-up assessment.

RESULTS

The study recruited 77 patients; 18 died during the study period and three ceased NPPV. Respiratory failure caused eight of the nine respiratory deaths (88.9%). One-, 2- and 5-year survival rates were 92.5%, 81.0% and 59.0%, respectively. In univariate analyses, higher night-time PaCO(2), base excess (night- and daytime) and lower Hb at baseline were associated with significantly worse survival (P < 0.05). Multivariate Cox regression analysis revealed night-time PaCO(2) as an independent predictor of survival (P = 0.042). The small differences in daily duration of use of NPPV and ventilator settings were not significantly related to survival. At follow up, significant improvements were observed for blood gases, lung and respiratory muscle function, as well as a decrease in Hb level (P < 0.01 each).

CONCLUSIONS

Base excess, Hb and particularly nocturnal PaCO(2) are relevant prognostic factors for survival in RTD and should be considered in assessing patients receiving NPPV.

Survival of patients on home mechanical ventilation: A nationwide prospective study

Home mechanical ventilation (HMV) is increasingly used as a therapeutic option to patients with symptomatic chronic hypoventilation. There is, however, a paucity of solid data on factors that could affect prognosis in patients on home ventilation. In the present study, our aim was to study several factors in these patients with potential influence on survival. We examined 1526 adult patients from a nationwide HMV register to which data had been reported prospectively for 10 years. The patients constituted a broad diagnostic spectrum and the primary outcome in this study was death. We found by far the poorest survival rate in the ALS patients with only 5% alive after 5 years. Among the other patient groups the survival pattern was more uniform and the scoliosis, polio and Pickwick patients presented the best survival rate, after 5 years being around 75%. No factors were associated with a greater hazard for death in the ALS patients; in the non-ALS patients, however, negative predictors for survival were age, concomitant use of oxygen therapy, tracheostomy ventilation and start of ventilatory support in an acute clinical setting. Center size or county specific home ventilation treatment prevalence did not affect survival. In conclusion, in a large material of patients on HMV we found by far the poorest survival in the ALS patients. In the non-ALS patients a number of patient-related factors affected survival, while the size of the treating center or the regional treatment prevalence did not.

Non-invasive positive ventilation in the treatment of sleep-related breathing disorders

This chapter addresses the use of long-term non-invasive positive pressure ventilation (NIPPV) (to the exclusion of continuous positive airway pressure) in the different clinical settings in which it is currently proposed: principally in diseases responsible for hypoventilation characterized by elevated PaCO(2). Nasal masks are predominantly used, followed by nasal pillow and facial masks. Mouthpieces are essentially indicated in case daytime ventilation is needed. Many clinicians currently prefer pressure-preset ventilator in assist mode as the first choice for the majority of the patients with the view of offering better synchronization. Nevertheless, assist-control mode with volume-preset ventilator is also efficient. The settings of the ventilator must insure adequate ventilation assessed by continuous nocturnal records of at least oxygen saturation of haemoglobin-measured by pulse oximetry. The main categories of relevant diseases include different types of neuromuscular disorders, chest-wall deformities and even lung diseases. Depending on the underlying diseases and on individual cases, two schematic situations may be individualized. Either intermittent positive pressure ventilation (IPPV) is continuously mandatory to avoid death in the case of complete or quasi-complete paralysis or is used every day for several hours, typically during sleep, producing enough improvement to allow free time during the daylight in spontaneous breathing while hypoventilation and related symptoms are improved. In case of complete or quasi-complete need of mechanical assistance, a tracheostomy may become an alternative to non-invasive access. In neuromuscular diseases, in kyphosis and in sequela of tuberculosis patients, NIPPV always significantly increases survival. Conversely, no data support a positive effect on survival in chronic obstructive pulmonary disease.

The effects of nocturnal home mechanical ventilation on daytime blood gas disturbances

INTRODUCTION

In chronic alveolar hypoventilation, previous studies of selected patient groups have shown that nocturnal home mechanical ventilation (HMV) may result in improvements in chronic blood gas disturbances during daytime spontaneous breathing. We wished to examine the effects of this treatment in a large sample of non-selected patients prospectively followed up, in a national multicentric register.

MATERIAL

A total of 288 patients from a broad diagnostic spectrum were studied. We looked at the blood gases and vital capacity before the patients elected for initiation of HMV and at the first register-recorded follow-up after 6-24 months.

RESULTS

We found statistically significant improvements in PO(2) and PCO(2) (approximately 1 kPa in both) and in base excess, but no changes in vital capacity or calculated alveolo-arterial gradient. All changes were independent of the observation period and only weakly diagnose-related.

DISCUSSION

Our findings extend those of previous studies, showing a relatively early and apparently stable improvement in blood gases after starting and continuing nocturnal HMV. The equal extent of the improvements in blood gases among all the diagnostic groups including the neurological patients with progressive diseases was unexpected.

CONCLUSION

In 288 patients starting nocturnal HMV electively we found significant improvements in daytime blood gases after 6-24 months. There were no changes in vital capacity or calculated alveolo-arterial gradient.

Performance of mechanical ventilators at the patient's home: a multicentre quality control study

BACKGROUND

Quality control procedures vary considerably among the providers of equipment for home mechanical ventilation (HMV).

METHODS

A multicentre quality control survey of HMV was performed at the home of 300 patients included in the HMV programmes of four hospitals in Barcelona. It consisted of three steps: (1) the prescribed ventilation settings, the actual settings in the ventilator control panel, and the actual performance of the ventilator measured at home were compared; (2) the different ventilator alarms were tested; and (3) the effect of differences between the prescribed settings and the actual performance of the ventilator on non-programmed readmissions of the patient was determined.

RESULTS

Considerable differences were found between actual, set, and prescribed values of ventilator variables; these differences were similar in volume and pressure preset ventilators. The percentage of patients with a discrepancy between the prescribed and actual measured main ventilator variable (minute ventilation or inspiratory pressure) of more than 20% and 30% was 13% and 4%, respectively. The number of ventilators with built in alarms for power off, disconnection, or obstruction was 225, 280 and 157, respectively. These alarms did not work in two (0.9%), 52 (18.6%) and eight (5.1%) ventilators, respectively. The number of non-programmed hospital readmissions in the year before the study did not correlate with the index of ventilator error.

CONCLUSIONS

This study illustrates the current limitations of the quality control of HMV and suggests that improvements should be made to ensure adequate ventilator settings and correct ventilator performance and ventilator alarm operation.