Effect of non-invasive mechanical ventilation on sleep and nocturnal ventilation in patients with chronic respiratory failure

High-intensity non-invasive ventilation in stable hypercapnic COPD: Evidence of efficacy and practical advice

Patients with end-stage chronic obstructive pulmonary disease (COPD) frequently develop chronic hypercapnic respiratory failure (CHRF), with disabling symptoms and poor survival. The use of long-term nocturnal non-invasive ventilation (NIV) to treat CHRF in COPD has long been subject of debate due to conflicting evidence. However, since the introduction of high-intensity NIV (HI-NIV) in COPD, physiological and clinical benefits have been shown. HI-NIV refers to specific ventilator settings used for NIV aimed at achieving normocapnia or the lowest partial arterial carbon dioxide pressure (PaCO₂ ) values as possible. This review will provide an overview of existing evidence of the efficacy of HI-NIV stable COPD patients with CHRF. Secondly, we will discuss hypotheses underlying NIV benefit in stable hypercapnic COPD, providing insight into better patient selection and hopefully more individually titrated HI-NIV. Finally, we will provide practical advice on how to initiate and follow-up patients on HI-NIV, with special emphasis on monitoring that should be available during the initiation and follow-up of HI-NIV, and will discuss more extended monitoring techniques that could improve HI-NIV treatment in the future.

Impact of home mechanical ventilation on sleep quality

PURPOSE OF REVIEW

The number of patients receiving home mechanical ventilation (HMV) has dramatically increased in recent years. Although physiological parameters, health-related quality of life and long-term outcomes frequently serve as primary outcomes, only a few studies have primarily addressed sleep quality in patients undergoing HMV. Therefore, this review article summarizes the current knowledge on sleep quality in patients receiving HMV.

RECENT FINDINGS

HMV can be performed noninvasively via face masks or invasively via tracheal cannulas. Studies in patients receiving invasive HMV therapy are clearly lacking. Most studies in this field have focused on invasively ventilated patients in the ICU, but the findings are not necessarily applicable to patients undergoing invasive HMV. On the other hand, there are several trials showing that noninvasive ventilation (NIV) has the potential to improve sleep quality in patients with severe sleep disturbances associated with chronic hypercapnic respiratory failure. To this end, both subjectively and objectively assessed sleep qualities by polysomnography are reported to improve after long-term NIV is initiated.

SUMMARY

Although HMV has the potential to improve sleep quality in patients with chronic hypercapnic respiratory failure, it can also have a negative impact on sleep quality, particularly in cases of patient-ventilator asynchrony or leakage. Therefore, both subjective and objective polysomnographic assessments of sleep quality should become an integral part of managing patients who receive HMV therapy.

Switch of noninvasive ventilation (NIV) to continuous positive airway pressure (CPAP) in patients with obesity hypoventilation syndrome: a pilot study

Background

Obesity is a major worldwide public health issue. The main respiratory complication stemming from obesity is obesity hypoventilation syndrome (OHS). Most of the OHS patients diagnosed during an exacerbation are treated with non invasive ventilation (NIV). Up to date, no prospective study has demonstrated in real life conditions the feasibility of a systematic protocoled switch of NIV to continuous positive airway pressure (CPAP), once stability is achieved.

Methods

In this prospective study, we included stable patients with OHS, with moderate to severe concomitant obstructive sleep apnea (OSA) and without obstructive pulmonary disease, who had been undergoing NIV for more than 2 months. The following measurements were performed, first with NIV and then after the switch to CPAP: diurnal arterial blood gas measurements; nocturnal oximetry and capnometry; mean compliance and AHI; measures of quality of life and quality of sleep.

Results

22/30 patients accepted to participate in the study and 15/22 patients completed the study. There were no significant differences for pooled data in diurnal alveolar blood gases, nocturnal capnometry (p = 0.534), nocturnal oximetry (p = 0.218), mean compliance (p = 0.766), mean AHI (p = 0.334), quality of life or quality of sleep. Eighty percent of the patients treated in this study favored CPAP over NIV.

Conclusion

This pilot study showed in real life conditions the possibility of a systematic switch of NIV to CPAP, in most stable patients with OHS, with similar efficacy on diurnal and nocturnal alveolar gas exchange, quality of life and quality of sleep.

Trial registration

ISRCTN13981084. Registered: 27 February 2017 (retrospectively registered)

Transcutaneous monitoring as a replacement for arterial PCO(2) monitoring during nocturnal non-invasive ventilation

BACKGROUND

Continuous, non-invasive assessment of alveolar ventilation achieved by transcutaneous PCO(2) (PtcCO(2)) monitoring is clearly superior to intermittent, invasive blood gas analyses in patients receiving nocturnal non-invasive positive pressure ventilation (NPPV), but the reliability and accuracy of PtcCO(2)-monitoring is still disputed. The present study was aimed at investigating the capability of modern PtcCO(2)-monitoring to reliably assess alveolar ventilation during nocturnal NPPV.

METHODS

Capillary blood gas measurements (11pm, 2am, 5am and 7am) and 8 h of continuous PtcCO(2)-monitoring using three of the latest generation devices (SenTec Digital Monitor, Radiometer TCM4-TINA and Radiometer TOSCA500) were performed during polysomnography-proven sleep studies in 24 patients receiving NPPV (15 with COPD, 9 with restrictive disorders).

RESULTS

The technical calibration drift for SenTec DM, TCM4-TINA and TOSCA500 was 0.1, -0.4 and -0.5 mmHg/h, respectively. Bland-Altman method comparison of PaCO(2)/drift-uncorrected PtcCO(2) revealed a mean bias (limits of agreement) of 1.0 (-4.7 to 6.7), -1.5 (-15.6 to 12.5) and 0.8 (-6.8 to 8.3) mmHg, respectively. Continuous overnight PtcCO(2)-monitoring detected variations in alveolar ventilation, with median ranges of 12.3 (10.7-14.5) mmHg for SenTec DM, 14.5 (12.5-17.0) mmHg for TCM4-TINA and 11.5 (11.0-13.0) mmHg for TOSCA500 (RM-ANOVA, p < 0.001). The four capillary PaCO(2) values ranged by a median of 6.3 (4.7-9.7) mmHg.

CONCLUSIONS

Modern PtcCO(2)-monitoring is reliable, accurate and robust. Since PtcCO(2)-monitoring is also non-invasive, does not disrupt sleep quality and provides a more complete picture of alveolar ventilation than intermittent capillary PaCO(2), PtcCO(2)-monitoring should become the preferred technique for assessing alveolar ventilation during nocturnal NPPV.

TRIAL REGISTRATION

DRKS00000433 at http://apps.who.int/trialsearch/default.aspx.

Sleep effects on breathing and respiratory diseases

To understand normal sleep pattern and physiological changes during sleep, sleep and breathing interaction, nomenclature and scales used in sleep study, discuss the effect of rapid eye movements and non-rapid eye movements while sleep and to review the effects of obstructive and restrictive lung disease on gas exchange during sleep and sleep architecture.

[Follow-up and management of non-invasive home mechanical ventilation]

Efficacy and tolerance of home non-invasive ventilation (NIV) must be assessed by using objective criteria (clinical evaluation, arterial blood gases, oxymetry, and research of side effects such as air leaks, skin problems, etc). In this article, we describe a procedure for long-term follow-up of home NIV. We also suggest an algorithm using available polygraphic tools to ascertain causes of NIV failure, in order to correct them.

Clinical review: long-term noninvasive ventilation

Noninvasive positive ventilation has undergone a remarkable evolution over the past decades and is assuming an important role in the management of both acute and chronic respiratory failure. Long-term ventilatory support should be considered a standard of care to treat selected patients following an intensive care unit (ICU) stay. In this setting, appropriate use of noninvasive ventilation can be expected to improve patient outcomes, reduce ICU admission, enhance patient comfort, and increase the efficiency of health care resource utilization. Current literature indicates that noninvasive ventilation improves and stabilizes the clinical course of many patients with chronic ventilatory failure. Noninvasive ventilation also permits long-term mechanical ventilation to be an acceptable option for patients who otherwise would not have been treated if tracheostomy were the only alternative. Nevertheless, these results appear to be better in patients with neuromuscular/-parietal disorders than in chronic obstructive pulmonary disease. This clinical review will address the use of noninvasive ventilation (not including continuous positive airway pressure) mainly in diseases responsible for chronic hypoventilation (that is, restrictive disorders, including neuromuscular disease and lung disease) and incidentally in others such as obstructive sleep apnea or problems of central drive.

Exercise endurance before and after long-term noninvasive ventilation in patients with chronic respiratory failure

BACKGROUND

Noninvasive mechanical ventilation (NIV) is known to reduce hypoventilation and improves respiratory and peripheral muscle endurance in patients with chronic respiratory failure (CRF) due to thoracic restriction.

OBJECTIVES

To compare the effect of short-term NIV on endurance in patients with CRF due to thoracorestriction and chronic obstructive pulmonary disease (COPD) and to evaluate differences in spiroergometric data during exercise testing.

METHODS

Thirty-five patients with CRF due to COPD and 24 patients with CRF due to thoracorestriction entered the trial. Constant work rate exercise testing at 75% of the maximal workload, pulmonary function and arterial blood gas testing were performed before and after 3 months of NIV. Measurements were compared between and within groups.

RESULTS

The non-COPD group increased their exercise time significantly from 4.7 +/- 1.81 to 6.59 +/- 3.15 min (p = 0.0032). There was no change in the COPD group (4.57 +/- 2.19 min before and 5.39 +/- 3.09 min after NIV, p = 0.09). CO(2) levels at rest fell in both groups (COPD 52.30 +/- 7.77 to 46.06 +/- 4.61 mm Hg and non-COPD 47.82 +/- 5.19 to 43.79 +/- 4.15 mm Hg). While COPD patients increased their minute ventilation (13.47 +/- 2.73 to 14.88 +/- 2.67 l/min), non-COPD patients decreased their oxygen uptake from 6.27 +/- 1.61 to 5.54 +/- 1.35 ml/kg.

CONCLUSIONS

NIV improved endurance only in the non-COPD group. This and the reduction in CO(2) are achieved by lowering energetic requirements. COPD patients though decreased their resting CO(2) by increased minute ventilation.

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.

Effect of sleep on patient/ventilator asynchrony in patients undergoing chronic non-invasive mechanical ventilation

BACKGROUND

Patients who require home non-invasive ventilation (NIV) during sleep normally have the ventilation settings adjusted empirically during daytime wakefulness. However, patient-ventilator asynchrony may occur during sleep. To detect the incidence of ineffective efforts (IE) during the sleep compared to wakefulness, we studied 48 patients already enrolled in a long-term home NIV programme.

METHODS

We evaluated arterial blood gases, breathing pattern during spontaneous breathing (SB) and ventilation during wakefulness. In addition, we assessed the breathing pattern and oxygen gas exchange during night-time NIV.

RESULTS

Daytime NIV significantly improved blood gases compared to SB (PaO2 NIV 10.2 +/- 1.95 kPa vs PaO2 SB 8 +/- 1.37, p < 0.001; PaCO2 NIV 5.75 +/- 1.08 kPa, vs PaCO2 SB 6.5 +/- 1.25, p < 0.001). The IE index was higher during sleep compared to wakefulness (48 +/- 39.5 events/h versus 0 +/- 0). The IE index was correlated with the time spent with SaO2 < 90% (r = 0.39, p < 0.01), but not with ventilator parameters, underlying disease, ventilation mode or type of mask. Eight patients had an IE index >100 events/h; these patients had a faster respiratory rate, required a higher level of inspiratory assistance and had poor gas exchange during sleep.

CONCLUSIONS

We conclude that IE to breath are common during nocturnal NIV and that they may be associated with desaturations even in patients who are considered compliant and effectively treated.

Impact of Ventilation Parameters and Duration of Ventilator Use on Non-Invasive Home Ventilation in Restrictive Thoracic Disorders

BACKGROUND

Non-invasive positive pressure ventilation (NPPV) is an accepted treatment option for chronic ventilatory failure due to restrictive thoracic disorders.

OBJECTIVE

The impact of ventilation setting and the duration of ventilator use on changes in physiological and functional parameters has not yet been evaluated.

METHODS

Effects of NPPV on body plethysmographic parameters, blood gas tension and inspiratory muscle function up to 12 months were analyzed in 44 patients with thoracic cage abnormalities in a clinical stable condition. Furthermore, the influence of ventilator parameters and the duration of ventilator use on these changes was determined.

RESULTS

A significant improvement in blood gas parameters (PaCO(2), PaO(2) and base excess; p < 0.001), lung volumes (VC, TLC and FEV(1); p < 0.001) and inspiratory muscle function (PI(max), P(0.1); p < 0.01 and p < 0.05) was found after 3.8 +/- 0.8 months of treatment. As shown by a subgroup analysis, changes were already achieved within the first 3 months of NPPV and then remained stable over time. Improvements in VC were positively correlated with IPAP (r = 0.55; p < 0.001). Reduction in PaCO(2) was positively correlated with the quotient (IPAP - EPAP)/weight (r = 0.55; p < 0.001). No correlation could be detected between changes in functional parameters and the duration of ventilator use.

CONCLUSIONS

NPPV can improve blood gas parameters, lung volume and inspiratory muscle function in thoracic restrictive disorders. To best utilize the potential of NPPV treatment, it seems to be more effective to optimize pressure levels than to extend the duration of ventilation.

Sleep-related breathing disorders

Sleep-related breathing disorders are a heterogeneous group of conditions that may be associated with alterations in the structure of sleep, in sleep quality, and in gas exchange during sleep. Obstructive sleep apnea represents the most frequent cause of sleep-related breathing disorders, which encompass a diversity of conditions that either complicate coexisting disease or present as primary disorders. Many of these disorders have consequences during both sleep and wakefulness and may produce substantial burden of symptoms and disease in untreated individuals.

Long-term reduction of hyperinflation in stable COPD by non-invasive nocturnal home ventilation

OBJECTIVE

The role of non-invasive positive pressure ventilation (NPPV) in stable COPD with chronic ventilatory failure remains controversial. The impact of long-term home nocturnal NPPV treatment on deflation has not yet been evaluated in detail.

METHODS

Retrospective explorative study of 46 patients with stable COPD undergoing NPPV treatment. Effects of NPPV on body plethysmographic parameters, blood gas tensions and inspiratory muscle function after 6.2 (+/-1.7) and 12.7 (+/-2.1) months of treatment. Further, evaluation of 1-year survival, compliance and ventilation parameters.

RESULTS

One-year survival was 89.1%. The effectiveness of ventilation was proven by a significant reduction in nocturnal and daytime PaCO2. We observed a decrease in the ratio of residual volume (RV) to total lung capacity (TLC) on the average of 5.2+/-9.8% (or 15.2+/-29.7% pred.; P<0.01) at six and 3.9+/-9.0% (or 12.9+/-18.6% pred.; P<0.001) at 12 months. As a consequence, we found significant improvements in inspiratory capacity (IC), vital capacity (VC) and forced expiratory volume in one second (FEV1). For patients with the most severe hyperinflation (RV/TLC>75%), we found a significant positive correlation between inspiratory positive airway pressure (IPAP) and reductions in PaCO2 (r=0.56; P<0.05) and RV/TLC (r=0.50; P<0.05).

CONCLUSIONS

In severe hypercapnic stable COPD long-term nocturnal NPPV can reduce hyperinflation with sustained improved daytime blood gas parameters.

Comparison of volume- and pressure-limited NPPV at night: a prospective randomized cross-over trial

Both pressure- and volume-limited non-invasive positive pressure ventilation (NPPV) have been used in patients with chronic respiratory failure. The aim of the present study was to compare the efficacy of ventilation during nocturnal volume- and pressure-limited NPPV. Fifteen patients (nine COPD, six non-COPD) were randomly assigned to receive either volume-limited or pressure-limited NPPV and were switched to the complementary mode after 6 weeks. Ten patients (five COPD, five non-COPD) completed the study. PaCO2 during sleep comparably decreased from 54.6+/-8.0 to 46.2+/-6.1 mmHg during volume-limited NPPV (P<0.05), and to 46.5+/-6.4 mmHg during pressure-limited NPPV (P<0.05). Improvements in sleep quality assessed by polysomnography were comparable, but less gastrointestinal side effects were reported for pressure-limited NPPV (P<0.05). Using a pneumotachograph the variance of inspiratory volumes was lower, but the variance of peak inspiratory pressures was higher during volume-limited NPPV compared to pressure-limited NPPV. Substantial leak volumes which accounted for 57% (volume-limited NPPV) and for 58% (pressure-limited NPPV) of the applied inspiratory volume were independent from the mode of ventilation. In conclusion, nocturnal volume- and pressure-limited NPPV have similar effects on gas exchange and sleep quality in patients with hypercapnic chronic respiratory failure, but volume-limited NPPV is associated with more gastrointestinal side effects.

[Analysis of withdrawal from noninvasive mechanical ventilation in patients with obesity-hypoventilation syndrome. Medium term results]

OBJECTIVE

To evaluate the possibility of cessation of noninvasive mechanical ventilation or noninvasive positive pressure ventilation (NPPV) treatment in patients with obesity-hypoventilation syndrome (OHS).

MATERIAL AND METHODS

A study was carried out on 22 OHS patients who had received NPPV for a minimum of 1 year. Prior to evaluation of the cessation of ventilatory support, all patients underwent the following tests: diurnal and nocturnal arterial blood gases, nocturnal oximetry, nocturnal cardiorespiratory polygraphy, and lung function tests. Based on the results obtained, 12 patients who met the NPPV cessation criteria were selected. This group was liberated from ventilatory support for 3 months. At the end of this period, all of the tests initially carried out were repeated on all patients and the results were compared with those obtained at the time of NPPV cessation.

RESULTS

Three months after liberation from NPPV, no significant variations were observed in arterial blood gases or in lung function tests in comparison with the values found at the time of cessation. In terms of individual development, only 1 patient showed blood gas deterioration requiring a return to NPPV. In 7 cases, a polygraph showed obstructive sleep apnea syndrome (OSAS), 4 at the time of cessation and 3 at the follow-up examination carried out at the end of the 3 months. Finally, in 4 patients the respiratory situation remained stable, with no significant variations in the tests done before or after cessation of NPPV.

CONCLUSIONS

The majority of the OHS patients who receive prolonged treatment with NPPV continue to be stable 3 months after liberation from ventilatory support. A high percentage of these patients can be seen to have OSAS once the hypercapnia situation is corrected.

Non-invasive ventilation and sleep

In this paper, we review the effects of nocturnal mechanical ventilation on sleep. Indeed, although non-invasive assisted ventilation during sleep has been applied extensively, the exact effects of this treatment on sleep quality have not been thoroughly studied. In patients with severe chronic obstructive pulmonary disease and severe restrictive ventilatory defects, the resulting respiratory failure is aggravated by the specific effects of sleep on respiration. Non-invasive mechanical ventilation can lead to improvements in both ventilation and sleep quality. However, this is not always the case. Moreover, sleep-related leaks may jeopardize the efficiency of the ventilatory assistance which in turn may result in a deterioration in sleep quality. Non-invasive mechanical ventilation, if applied during sleep, should require a monitoring procedure during sleep with the aim of obtaining the best possible effects both on ventilation and on sleep quality.