Nocturnal noninvasive positive pressure ventilatory assistance

Utility of Transcutaneous Capnography for Optimization of Non-Invasive Ventilation Pressures

INTRODUCTION

Nocturnal Non-invasive Positive Pressure Ventilation (NPPV) is the treatment of choice in patients with chronic hypercapnic respiratory failure due to hypoventilation. Continuous oxygen saturation measured with a pulse oximeter provides a surrogate measure of arterial oxygen saturation but does not completely reflect ventilation. Currently, Partial Pressure of Arterial (PaCO2) measured by arterial blood analysis is used for estimating the adequacy of ventilatory support and serves as the gold standard.

AIM

To examine the safety, feasibility and utility of cutaneous capnography to re-titrate the non-invasive positive pressure ventilation settings in patients with chronic hypercapnic respiratory failure due to hypoventilation.

MATERIALS AND METHODS

Twelve patients with chronic hypercapnic respiratory failure prospectively underwent complete polysomnography and cutaneous capnography measurement on the ear lobe. Non-invasive ventilation pressures were adjusted with the aim of normalizing cutaneous carbon dioxide or at least reducing it by 10 to 15 mmHg. Sensor drift for cutaneous carbon dioxide of 0.7 mmHg per hour was integrated in the analysis.

RESULTS

Mean baseline cutaneous carbon dioxide was 45.4 ± 6.5 mmHg and drift corrected awake value was 45.1 ± 8.3 mmHg. The correlation of baseline cutaneous carbon dioxide and the corrected awake cutaneous carbon dioxide with arterial blood gas values were 0.91 and 0.85 respectively. Inspiratory positive airway pressures were changed in nine patients (75%) and expiratory positive airway pressures in eight patients (66%). Epworth sleepiness score before and after the study showed no change in five patients, improvement in six patients and deterioration in one patient.

CONCLUSION

Cutaneous capnography is feasible and permits the optimization of non-invasive ventilation pressure settings in patients with chronic hypercapnic respiratory failure due to hypoventilation. Continuous cutaneous capnography might serve as an important additional tool to complement diurnal arterial carbon dioxide tension values.

Nocturnal mechanical ventilation for chronic hypoventilation in patients with neuromuscular and chest wall disorders

BACKGROUND

Chronic alveolar hypoventilation is a common complication of many neuromuscular and chest wall disorders. Long-term nocturnal mechanical ventilation is commonly used to treat it. This is a 2014 update of a review first published in 2000 and previously updated in 2007.

OBJECTIVES

To examine the effects on mortality of nocturnal mechanical ventilation in people with neuromuscular or chest wall disorders. Subsidiary endpoints were to examine the effects of respiratory assistance on improvement of chronic hypoventilation, sleep quality, hospital admissions and quality of life.

SEARCH METHODS

We searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL, MEDLINE and EMBASE on 10 June 2014. We contacted authors of identified trials and other experts in the field.

SELECTION CRITERIA

We searched for quasi-randomised or randomised controlled trials of participants of all ages with neuromuscular or chest wall disorder-related stable chronic hypoventilation of all degrees of severity, receiving any type and any mode of long-term nocturnal mechanical ventilation. The primary outcome measure was one-year mortality and secondary outcomes were unplanned hospital admission, short-term and long-term reversal of hypoventilation-related clinical symptoms and daytime hypercapnia, improvement of lung function and sleep breathing disorders.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology to select studies, extract data and assess the risk of bias in included studies.

MAIN RESULTS

The 10 eligible trials included a total of 173 participants. Roughly half of the trials were at low risk of selection, attrition or reporting bias, and almost all were at high risk of performance and detection bias. Four trials reported mortality data in the long term. The pooled risk ratio (RR) of dying was 0.62 (95% confidence interval (CI) 0.42 to 0.91, P value = 0.01) in favour of nocturnal mechanical ventilation compared to spontaneous breathing. There was considerable and significant heterogeneity between the trials, possibly related to differences between the study populations. Information on unplanned hospitalisation was available from two studies. The corresponding pooled RR was 0.25 (95% CI 0.08 to 0.82, P value = 0.02) in favour of nocturnal mechanical ventilation. For most of the outcome measures there was no significant long-term difference between nocturnal mechanical ventilation and no ventilation. Most of the secondary outcomes were not assessed in the eligible trials. Three out of the 10 trials, accounting for 39 participants, two with a cross-over design and one with two parallel groups, compared volume- and pressure-cycled non-invasive mechanical ventilation in the short term. From the only trial (16 participants) on parallel groups, there was no difference in mortality (one death in each arm) between volume- and pressure-cycled mechanical ventilation. Data from the two cross-over trials suggested that compared with pressure-cycled ventilation, volume-cycled ventilation was associated with less sleep time spent with an arterial oxygen saturation below 90% (mean difference (MD) 6.83 minutes, 95% CI 4.68 to 8.98, P value = 0.00001) and a lower apnoea-hypopnoea (per sleep hour) index (MD -0.65, 95% CI -0.84 to -0.46, P value = 0.00001). We found no study that compared invasive and non-invasive mechanical ventilation or intermittent positive pressure versus negative pressure ventilation.

AUTHORS' CONCLUSIONS

Current evidence about the therapeutic benefit of mechanical ventilation is of very low quality, but is consistent, suggesting alleviation of the symptoms of chronic hypoventilation in the short term. In four small studies, survival was prolonged and unplanned hospitalisation was reduced, mainly in participants with motor neuron diseases. With the exception of motor neuron disease and Duchenne muscular dystrophy, for which the natural history supports the survival benefit of mechanical ventilation against no ventilation, further larger randomised trials should assess the long-term benefit of different types and modes of nocturnal mechanical ventilation on quality of life, morbidity and mortality, and its cost-benefit ratio in neuromuscular and chest wall diseases.

Nocturnal mechanical ventilation for chronic hypoventilation in patients with neuromuscular and chest wall disorders

BACKGROUND

Chronic alveolar hypoventilation is a common complication of many neuromuscular and chest wall disorders. Long-term nocturnal mechanical ventilation is increasingly used to treat it.

OBJECTIVES

To examine the efficacy of nocturnal mechanical ventilation in relieving hypoventilation related symptoms and in prolonging survival in people with neuromuscular or chest wall disorders.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Trials Register, MEDLINE (from January 1966 to June 2006), and EMBASE (from January 1980 to June 2006) for randomised trials and contacted authors of trials and other experts in the field.

SELECTION CRITERIA

We searched for quasi-randomised or randomised controlled trials of participants with neuromuscular or chest wall disorder-related stable chronic hypoventilation of all ages and all degrees of severity, receiving any type and any mode of nocturnal mechanical ventilation. The primary outcome measure was short-term and long-term reversal of hypoventilation related clinical symptoms and secondary outcomes were unplanned hospital admission, one year mortality, short-term and long-term reversal of daytime hypercapnia, improvement of lung function and sleep breathing disorders.

DATA COLLECTION AND ANALYSIS

We identified eight randomised trials.

MAIN RESULTS

The eight eligible trials included a total of 144 participants. The relative risk of 'no improvement of hypoventilation related clinical symptoms' in the short-term following nocturnal mechanical ventilation was available in only one trial with 10 participants and was not significant, 0.09 (95% confidence interval (CI) 0.01 to 1.31). The relative risk of 'no reversal of daytime hypercapnia' in the short-term following nocturnal ventilation was significant and favoured treatment, 0.37 (95% CI 0.20 to 0.65). The weighted mean difference of nocturnal mean oxygen saturation was 5.45% (95% CI 1.47 to 9.44) more improvement in participants treated with nocturnal mechanical ventilation. For most of the outcome measures there was no significant long-term difference between nocturnal mechanical ventilation and no ventilation. However, the estimated risk of death based on three studies was reduced following nocturnal ventilation, 0.62 (95% CI 0.42 to 0.91). There was considerable and significant heterogeneity between the trials possibly related to differences between the study populations. Most of the secondary outcomes were not assessed in the eligible trials. Data from two crossover trials suggested no evidence for a difference in reversal of daytime hypercapnia and sleep study parameters between volume-cycled and pressure-cycled ventilation. No data could be summarised for the comparisons between invasive and non-invasive mechanical ventilation or between intermittent positive pressure and negative pressure ventilation.

AUTHORS' CONCLUSIONS

Current evidence about the therapeutic benefit of mechanical ventilation is weak, but consistent, suggesting alleviation of the symptoms of chronic hypoventilation in the short-term. In three small studies survival was prolonged mainly in participants with motor neuron diseases. With the exception of motor neuron disease, further larger randomised trials are needed to confirm long-term beneficial effects of nocturnal mechanical ventilation on quality of life, morbidity and mortality, to assess its cost-benefit ratio in neuromuscular and chest wall diseases and to compare the different types and modes of ventilation.

Noninvasive ventilation

Noninvasive positive-pressure ventilation (NPPV) is the delivery of mechanical-assisted breathing without placement of an artificial airway such as an endotracheal tube or tracheostomy. During the first half of 20th century, negative-pressure ventilation (iron lung) provided mechanical ventilatory assistance. By the 1960s, however, invasive (ie, by means of an endotracheal tube) positive-pressure ventilation superseded negative-pressure ventilation as the primarily mode of support for ICU patients because of its superior delivery of support and better airway protection. Over the past decade, the use of NPPV has been integrated into the treatment of many medical diseases, largely because the development of nasal ventilation. Nasal ventilation has the potential benefit of providing ventilatory assistance with greater convenience, comfort, safety, and less cost than invasive ventilation. NPPV is delivered by a tightly fitted mask or helmet that covers the nares, face, or head. NPPV is used in various clinical settings and is beneficial in many acute medical situations. This article explores the trends regarding the use of noninvasive ventilation. It also provides a current perspective on applications in patients with acute and chronic respiratory failure, neuromuscular disease, congestive heart failure, and sleep apnea. Additionally, it discusses the general guidelines for application, monitoring, and avoidance of complications for NPPV.

Correcting arterial blood gases for temperature: (when) is it clinically significant?

Interpreting arterial blood gases (ABGs) is a common practice in intensive care units. The use of the temperature correction facility, however, is not standardized, and the effects of temperature correction on the ABG result may affect the overall management of the patient. The aim of this study was to discuss the significance of temperature correction. Current practice in the UK and Australia is discussed along with a review of physiological principles of oxygenation and acid-base balance. The alpha-stat and pH-stat methods of blood gas analysis are presented, with arguments for and against using the temperature correction facility for blood gas analysis. The study concludes with recommendations for practice.

Technological dependency - the experience of using home ventilators and long-term oxygen therapy: patients' and families' perspective

Technological dependency is defined as a short or long-term reliance on machines and techniques to evaluate, satisfy or resolve health problems. In nursing technological dependency has been explored in the context of caring. Hitherto it has been maintained that technology and caring are contradictory, but a more prominent view is that technology and caring can and must be reconciled to provide high-quality care. This study describes patients' and families' experience of long-term home treatment with noninvasive ventilation during sleep with or without additional oxygen therapy. Considering the potential burden of undergoing this treatment the research question is: What is patients' and families' experience of being dependent on technical breathing assistance during sleep? The methodological approach draws from interpretive phenomenology and narrative analysis. Participants were six patients aged 45-70, five spouses and one daughter. Data, generated through two 1-hour semi-structured interviews with each pair of participants, were analysed into themes. Results are presented by the following narratives: (i) mixed blessing: life-saving treatment - meaningless exertion; (ii) compassion and understanding central amid use of complex machines; (iii) listening to the body; (iv) wanting to be seen as healthy; (v) dominance of technological thinking; and (vi) sustained work in maintaining the treatment. It is concluded that being dependent on technical breathing assistance during sleep, with or without oxygen, was a major life event for participants. The treatment was experienced as constraining and intrusive, particularly at the beginning, but concurrently it dramatically relieved difficulties for most participants. Regardless of its usefulness it provoked questions on purpose, indicating that the way to implement the treatment is crucial. Professionals need to pay close attention to how they introduce noninvasive ventilation technique, putting caring concern and respect for unique needs of patients and their families at the forefront.

Noninvasive ventilation using bilevel positive airway pressure to treat impending respiratory failure in the postanesthesia care unit

The author presents the use of noninvasive positive pressure ventilation using bilevel positive airway pressure (BiPAP) to treat respiratory insufficiency and hypoxemia in three patients in the postanesthesia care unit. BiPAP improved respiratory function with a decreased respiratory rate, decreased PaCO2, and improved oxygenation in the three patients. The applications of these techniques and equipment required are reviewed.

Nocturnal mechanical ventilation for chronic hypoventilation in patients with neuromuscular and chest wall disorders

BACKGROUND

Chronic alveolar hypoventilation is a common complication of many neuromuscular and chest wall disorders. Long term nocturnal mechanical ventilation is used to treat an increasing number of patients.

OBJECTIVES

To examine the efficacy of nocturnal mechanical ventilation in relieving hypoventilation related symptoms in patients with neuromuscular or chest wall disorders.

SEARCH STRATEGY

Search of the Cochrane Neuromuscular Disease Group register for randomized trials and enquiry from authors of trials and other experts in the field.

SELECTION CRITERIA

Types of studies: quasi-randomized or randomized controlled trials

TYPES OF PARTICIPANTS

patients with neuromuscular or chest wall disorder-related stable chronic hypoventilation of all ages and all degrees of severity. Types of interventions: any type and any mode of nocturnal mechanical ventilation. Types of outcome measures: Primary: short term and long term reversal of hypoventilation related clinical symptoms Secondary: unplanned hospital admission rate, one year mortality, short term and long term reversal of day time hypercapnia, improvement of lung function and improvement of sleep breathing disorders.

DATA COLLECTION AND ANALYSIS

We identified four randomized trials. One author extracted the data and another checked them. Individual data were available from the authors of the largest study.

MAIN RESULTS

The four eligible trials included a total of 51 patients. The risk difference (proportion of patients) of no improvement of hypoventilation related clinical symptoms in the short term following nocturnal mechanical ventilation was significant and favoured treatment, -0.417 (95% CI -0.639 to -0.194). However, there was significant heterogeneity across the studies (p<0.001). Similarly, the risk difference of no reversal of day time hypercapnia in the short term following nocturnal ventilation was significant and favoured treatment, -0.635 (95% CI -0.874 to -0.396). The weighted mean difference of nocturnal mean oxygen saturation percent was 5.5 (95% CI 1.5 to 9.4) more improvement in patients treated with nocturnal mechanical ventilation. For the primary and most of the secondary outcome measures there was no significant difference between nocturnal mechanical ventilation and no ventilation in the long term, except for one-year mortality. Indeed, the risk difference of death one year following implementation of nocturnal mechanical ventilation was significant and favoured treatment, -0.259 (95% CI -0.478 to -0. 041). However, there was significant heterogeneity across the studies (p<0.001). Most of the secondary outcomes were not assessed in the eligible trials. No data could be summarised for the comparisons between invasive and non-invasive mechanical ventilation, between intermittent positive pressure and negative pressure ventilation, and between volume-cycled and pressure-cycled ventilation.

REVIEWER'S CONCLUSIONS

Current evidence about the therapeutic benefit of mechanical ventilation is weak, but consistent, suggesting alleviation of the symptoms of chronic hypoventilation in the short term, and in two small studies survival was prolonged. Mechanical ventilation should be offered as a therapeutic option to patients with chronic hypoventilation due to neuromuscular diseases. Further larger randomized trials are needed to confirm long term beneficial effects of nocturnal mechanical ventilation on quality of life, morbidity and mortality, to assess its cost-benefit ratio, and to compare the different types and modes of ventilation.

Effects of conventional physiotherapy, continuous positive airway pressure and non-invasive ventilatory support with bilevel positive airway pressure after coronary artery bypass grafting

BACKGROUND

Coronary artery bypass graft (CABG) surgery with the use of mammary arteries is associated with severe alteration of lung function parameters. The purpose of the present study was to compare the effect on lung function tests of conventional physiotherapy using incentive spirometry (IS) with non-invasive ventilation on continuous positive airway pressure (CPAP) and with non-invasive ventilation on bilevel positive airway pressure (BiPAP or NIV-2P), METHODS: Ninety-six patients were randomly assigned to 1 of 3 groups: NIV-2P (1 h/3 h), CPAP (1 h/3 h) and IS (20/2 h). Pulmonary function tests and arterial blood gases analyses were obtained before surgery. On the 1st and 2nd postoperative days, these parameters were collected together with cardiac output and calculation of venous admixture.

RESULTS

For the 3 groups a severe restrictive pulmonary defect was observed during the 1st postoperative day. On the 2nd postoperative day, in opposition to IS, intensive use of CPAP and NIV-2P reduced significantly the venous admixture (P<0.001) and improved VC, FEV1 and PaO2 (P<0.01).

CONCLUSION

We conclude that preventive use of NIV can be considered as an effective means to decrease the negative effect of coronary surgery on pulmonary function.

Indications for positive airway pressure treatment of adult obstructive sleep apnea patients: a consensus statement

We developed a short-length document that clearly delineates a prudent approach to and criteria for reimbursement of positive airway pressure (PAP) costs for the treatment of obstructive sleep apnea (OSA). Treatment modalities for OSA with PAP include continuous positive airway pressure, bilevel or variable PAP, and autotitrating PAP. This guidance on the appropriate criteria for PAP use in OSA is based on widely acknowledged peer-reviewed studies and widely accepted clinical practice. These criteria reflect current opinion on the appropriate clinical management of OSA in lieu of data pending from the Sleep Heart Health Study and upcoming outcome studies. This document is not intended to provide a complete review and analysis of the OSA clinical literature. The key to the success of this document is to foster consensus within and outside the clinical sleep community by providing a common sense and easily understood approach to the treatment of OSA with PAP.

Noninvasive ventilation in neuromuscular disease

The treatment of respiratory failure in patients who have NMD continues to be an evolving process. Negative-pressure ventilation, once prominent in the 1940s and 1950s, gave way to intermittent positive-pressure ventilation with tracheostomy or endotracheal tubes in the 1960s. Now there is a resurgence of noninvasive ventilation, brought about by innovative modes of positive pressure delivered through nasal and facial masks. Although frequently relegated to second-line choices, negative-pressure devices still offer a practical treatment alternative as patient preference still plays a role in selecting a proper mode of ventilation. Studies have shown that noninvasive ventilation can prevent or reverse respiratory failure and improve quality of life and longevity. Despite the seemingly widespread acceptance of noninvasive ventilation in the treatment of respiratory failure, physicians still appear reluctant to use ventilatory assistance in the neuromuscular arena. In 1985, a survey found that respiratory support systems were utilized routinely in only 33% of the 132 responding Muscular Dystrophy Association (MDA) clinics. Bach recently surveyed 273 MDA clinic directors and co-directors from 167 clinics, to evaluate their current use of mechanical ventilation. Ventilatory assistance was recommended and used electively in only 43 (26%) of the 167 clinics. Furthermore, it was the policy in 68 of the clinics to discourage the use of mechanical ventilation. Even more importantly, only 2 physicians who discouraged the use of mechanical ventilation were familiar with the newest noninvasive methods of ventilatory support. Sadly, although our methodologies in the treatment of respiratory failure continue to improve, physician practice has lagged behind. Physicians who treat patients who have NMD need to become cognizant of these new techniques and incorporate them into their present therapeutic armamentarium.

Failure of CPAP therapy in obstructive sleep apnoea syndrome: predictive factors and treatment with bilevel-positive airway pressure

Continuous positive airway pressure (CPAP) is the most widely used therapy for obstructive sleep apnoea (OSA). Despite its general efficacy, oxygen desaturation due to hypoventilation persists in some patients. The present study analysed the factors which are associated with this primary failure and, moreover, examined the effect of a bilevel positive airway pressure (BiPAP) trial. In a 15-month period, 13 patients with OSA (Group A) failed to respond to initial CPAP therapy defined by a remaining apnoea/hypopnoea index (AHI) of > or = 5 or a mean nocturnal SaO2 < 90%. These patients were compared to an age- and AHI-matched control group (Group B) successfully treated by CPAP. A logistic regression analysis was performed to identify factors which are associated with initial failure to CPAP. Patients of the CPAP-failure group were treated with nasal BiPAP in the control mode. These patients were significantly more obese than patients of the control group (mean body mass index 44.2 +/- 7.7 vs 31.2 +/- 6.3 kg m-2; P < 0.001). PaO2 at rest (P < 0.001) and at exercise (P < 0.005) was significantly lower in Group A patients. PaCO2 at rest (P < 0.001) was significantly higher in Group A patients and changed for the worse during exercise, whereas it improved in the control group. Group A patients spent significantly (P < 0.0001) more time with oxygen saturation < 90%. The percentage of time spent at < 90% of SaO2 was the only factor which was independently associated with the initial failure of CPAP (OR 1.13; 95% CI 1.0-1.2). After 3 months of treatment with BiPAP, the patients' blood gas values while awake improved significantly (P < 0.05) for PaO2 as well as for PaCO2. In conclusion, patients with OSA resistant to initial CPAP are morbidly obese with impaired awake blood gas values. The percentage of time spent at < 90% of nocturnal SaO2 is independently associated with initial failure of CPAP. BiPAP in the control mode is adequate for nocturnal ventilation, and improves awake blood gas values.