Physiotherapy involvement in non-invasive ventilation hospital services: a British Isles survey

The aim of this study was to assess the involvement of physiotherapists in the delivery of non-invasive ventilation (NIV) services in the British Isles. A postal questionnaire was sent to all senior physiotherapists in hospitals providing specialist respiratory medicine. The response rate was 88% (269/305). Physiotherapists were involved in managing patients using NIV in 212/233 hospitals that used NIV. The majority of physiotherapists, 97% (206/212), were involved in treating patients on NIV. Physiotherapists assessed patients for NIV in 68% (145/212) of hospitals and were involved in setting up patients on NIV in 46% (97/212) of hospitals. There were no major differences between countries, within the British Isles, in the level of involvement of Physiotherapists in the management of patients on NIV. Physiotherapists need to develop specialist skills with regard to assessment and setting up patients on NIV if they want to expand their role in the management of patients on NIV.

Sequential use of oxygen and bi-level ventilation for respiratory failure in cystic fibrosis

BACKGROUND

Supplemental nocturnal oxygen is widely used for hypoxaemic respiratory failure in adults with CF.

METHODS

In order to determine the factors that predict the development of progressive hypercapnia on oxygen ("failure of oxygen therapy") and the subsequent role of bi-level pressure support ventilation (BVS), we reviewed the outcomes of 39 adults with CF who were treated for hypoxaemic respiratory failure between 1991 and 2002 using strict physiological criteria for the commencement of oxygen and the subsequent commencement of BVS.

RESULTS

Twenty of the 39 failed oxygen therapy, 13 of these within 12 months. Baseline PaCO2, rather than age, BMI or FEV1, predicted failure of oxygen therapy within 12 months. A PaCO2>6.5 kPa (49 mm Hg) was significantly associated with failure within 12 months (p=0.04). Twenty patients with mean PaCO2 7.9+/-1.3 kPa (59+/-10 mm Hg) and mean pH 7.38+/-0.05 had a significant reduction in their mean PaCO2 after 1 month of BVS (p=0.007).

CONCLUSIONS

Both oxygen and BVS can successfully stabilise patients to transplant. In patients commencing oxygen, baseline PaCO2 is predictive of the development of progressive hypercapnia within 12 months. BVS can successfully attenuate the rise in PaCO2 in the short term.

Sleep disordered breathing in cystic fibrosis

Cough, sleep fragmentation and oxyhaemoglobin desaturation have all been documented during sleep in patients with cystic fibrosis (CF). It has been proposed that repeated episodes of nocturnal hypoxia act as a stimulus for the development of pulmonary hypertension and right ventricular failure, a complication that is associated with a poor prognosis. In addition, sleep disturbance from these events could lead to poor daytime function and quality of life. This review provides a detailed description of the mechanisms underlying sleep disordered breathing in this population, what is known regarding its effects upon daytime function and current treatment options. Most importantly, we review what is needed from future research in this challenging area of care in patients with CF.

Nasal versus full face mask for noninvasive ventilation in chronic respiratory failure

This study was undertaken to determine the efficacy of nasal mask (NM) versus full face mask (FFM) for the delivery of noninvasive ventilation (NIV) in subjects with nocturnal hypoventilation. A total of 16 patients (11 males) were enrolled, all with nocturnal hypoventilation currently treated at home with NIV via pressure preset devices. Subjects underwent full polysomnography on three occasions; on the first night current therapy on NM was reviewed, followed by two experimental studies in randomised order using either NM or FFM. NIV settings and oxygen flow rate were the same under both conditions. Notably, 14 of the 16 subjects required the use of a chinstrap to minimise oral leak. Apnoea-hypopnoea indices were within normal limits under both conditions (1.7 +/- 3.4 NM versus 1.6 +/- 2.4 h FFM). The type of interface did not significantly affect gas exchange during sleep (minimum average arterial oxyhaemoglobin saturation total sleep time 93.4 +/- 2.1 NM versus 92.8 +/- 2.5% FFM, Delta transcutaneous carbon dioxide nonrapid eye movement sleep to rapid eye movement sleep (0.58 +/- 0.36 NM versus 0.50 +/- 0.40 kPa FFM). Sleep efficiency was significantly reduced on the FFM (78 +/- 9 NM versus 70 +/- 14% FFM), although arousal indices were comparable under both conditions (15.6 +/- 9.8 NM versus 15.8 +/- 8.8 h FFM). Full face masks appear to be as effective as nasal masks in the delivery of noninvasive ventilation to patients with nocturnal hypoventilation. However, a chinstrap was required to reduce oral leak in the majority of subjects using the nasal mask.

Subjective sleep quality in cystic fibrosis

OBJECTIVES

To evaluate sleep quality in patients with cystic fibrosis (CF).

METHODS

The Pittsburgh Sleep Quality Index (PSQI) questionnaire was administered to 37 CF patients with moderate to severe lung disease in a clinically stable state. Sleep studies were performed concurrently. PSQI scores were correlated with results of anthropometric variables, arterial blood gas tensions, lung function variables, and polysomnographic variables. Potential differences in objective measurements between patients with high and low scores on the PSQI were assessed.

RESULTS

Thirty-seven patients with CF were studied, aged 27+/-8 (mean+/-1 SD) years and forced expiratory volume in 1 s (FEV(1)) 36+/-12% predicted. The mean PSQI was 5.7+/-4.0. Fourteen of the 37 patients had a high PSQI, i.e. >5. Significant correlations between objective variables and both component scores and total PSQI were as follows: age and 'subjective sleep quality' (r=0.4, P<0.05), age and 'sleep duration' (r=0.3, P<0.05), FEV(1) % predicted and 'subjective sleep quality' (r=-0.4, P<0.05), carbon monoxide transferred per litre of lung volume (KCO) % predicted and 'daytime dysfunction' (r=-0.4, P<0.01), PaCO(2) and 'sleep latency' (r=0.4, P<0.01), arterial carbon dioxide tension (PaCO(2)) and 'habitual sleep efficiency' (r=0.3, P<0.05), PaCO(2) and total PSQI (r=0.4, P<0.05), absolute minimum sleep oxyhemoglobin saturation by pulse oximetry (SpO(2) %) and 'sleep latency' (r=-0.4, P<0.05), absolute minimum sleep SpO(2) % and 'sleep duration' (r=-0.4, P<0.05), absolute minimum sleep SpO(2) % and total PSQI (r=-0.4, P<0.05) and awake transcutaneous CO(2) and 'sleep duration' (r=0.45, P<0.05). Better sleep efficiency (P<0.05) and a greater % of rapid eye movement (REM) sleep (P<0.05) were found in those patients with a PSQI of < or =5.

CONCLUSIONS

A number of CF patients reported poor sleep quality. A relationship was shown between subjective sleep quality and physiological variables describing disease severity. Better sleep efficiency and % REM sleep were seen in patients with low PSQI scores. These results suggest a useful role for the PSQI in assessing sleep quality in patients with CF.

Night-to-night variability in sleep in cystic fibrosis

OBJECTIVES

The impact of night-to-night variability (NNV) on polysomnography (PSG) has been reported mainly in normal subjects, the elderly and patients with obstructive sleep apnea with focus on changes in the apnea/hypopnea index, rather than measures of nocturnal oxygenation. There is very limited data on NNV in patients with cystic fibrosis (CF). The goal of this study was to assess for first-night effect and reliability of PSG measurements on nocturnal oxygenation and respiratory disturbance in CF.

METHODS

A prospective observational study was performed in patients with CF who consented to PSG on two consecutive nights. Paired t-tests and intra-class correlation coefficients (ICCs) were calculated for repeated measures of sleep stage time, sleep efficiency, arousal indices, measures of nocturnal oxygenation, and respiratory events in all sleep stages.

RESULTS

Thirty-one patients with CF were studied, aged 27+/-8 (mean+/-1 SD) years and forced expiratory volume in 1 s (FEV(1)) of 37+/-11% of predicted. Relative to the first-night PSG, on the second PSG, we observed the following: shorter latency to rapid eye movement (REM) sleep (P<0.001), increased sleep efficiency (P<0.01), decreased wake after sleep onset (WASO) time (P<0.01), decreased percentage of non-REM time with oxyhemoglobin saturation by pulse oximetry (SpO(2))< or =90% (P<0.05), decreased number of central apneas per hour (P<0.05) and reduced respiratory rate in stage 2 sleep on night 2 (P<0.05). Despite these changes, the ICCs between night 1 and night 2 showed good repeatability/reliability for measures of nocturnal oxygenation and indices of respiratory disturbance, including the percentage of total sleep time with SpO(2)< or =90% (ICC=0.85) and apnea-hypopnea index (ICC=0.75). Likewise, the ICCs were extremely high for respiratory rate in stage 2 (ICC=0.94), slow wave sleep (ICC=0.97), and REM sleep (ICC=0.96).

CONCLUSION

Although a first-night effect is seen with sleep efficiency, REM latency, and WASO, a single-night PSG in patients with CF yields reliable information on nocturnal oxygenation and respiratory disturbance.

Predicting sleep-disordered breathing in patients with cystic fibrosis

STUDY OBJECTIVES

To examine predictors of sleep-disordered breathing in patients with cystic fibrosis (CF) and moderate-to-severe lung disease using a comprehensive evaluation of both sleep and daytime function.

DESIGN

Cross-sectional analysis of sleep studies, lung function, respiratory muscle strength, and evening and morning arterial blood gas measurements in patients with stable CF. A questionnaire addressing sleep quality was administered. Forward stepwise regression analysis was used to identify the parameters that best predict sleep-related desaturation, hypercapnia, and respiratory disturbance.

SETTING

Sleep investigation unit and lung function laboratory.

PATIENTS

Thirty-two patients with CF and FEV(1) < 65% predicted, in stable clinical condition. Patients were aged 27 +/- 8 years (mean +/- 1 SD) with FEV(1) of 36 +/- 10% predicted, evening PaO(2) of 68 +/- 8 mm Hg, and PaCO(2) of 43 +/- 5 mm Hg.

RESULTS

Evening PaO(2) (p < 0.0001) and morning PaCO(2) (p < 0.01) were predictive of the average minimum oxyhemoglobin saturation per 30-s epoch of sleep (r(2) = 0.74; p < 0.0001). Evening PaO(2) (p < 0.001) was predictive of the rise in transcutaneous carbon dioxide (TcCO(2)) seen from non-rapid eye movement (NREM) to rapid eye movement (REM) sleep (r(2) = 0.37; p < 0.001). In addition, there was some relationship between expiratory respiratory muscle strength and the REM respiratory disturbance index (r(2) = 0.22; p < 0.01).

CONCLUSION

Evening PaO(2) was found to contribute significantly to the ability to predict both sleep-related desaturation and the rise in TcCO(2) from NREM sleep to REM sleep in this subgroup of patients with CF.

Noninvasive pressure preset ventilation for the treatment of Cheyne-Stokes respiration during sleep

Cheyne-Stokes respiration (CSR) during sleep is common in patients with congestive heart failure (CHF). This pattern of breathing fragments sleep, leading to daytime symptoms of sleepiness and fatigue. It was hypothesized that by controlling CSR with noninvasive pressure preset ventilation (NPPV), there would be a decrease in sleep fragmentation and an improvement in sleep quality. Nine patients (eight males, one female; mean +/- SD 65 +/- 11 yrs) with symptomatic CSR diagnosed on overnight polysomnography (apnoea/hypopnoea index (AHI) 49 +/- 10 x h(-1), minimum arterial oxygen saturation (Sa,O2, 77 +/- 7%) and CHF (left ventricular ejection fraction 25 +/- 8%) were studied. After a period of acclimatization to NPPV (variable positive airway pressure (VPAP) II ST, Sydney, NSW, Australia and bilevel positive airway pressure (BiPAP), Murraysville, PA, USA), sleep studies were repeated on therapy. NPPV almost completely abolished CSR in all patients with a reduction in AHI from 49 +/- 10 to 6 +/- 5 x h(-1) (p<0.001). Residual respiratory events were primarily due to upper airway obstruction at sleep on-set. Arousal index was markedly decreased from 42 +/- 6 to 17 +/- 7 x h(-1) (p <0.001). Sleep architecture showed a trend toward improvement with a reduction in stage 1 and 2 (79 +/- 7% during the diagnostic night versus 72 +/- 10% during NPPV, (p=0.057)), whilst sleep efficiency, slow-wave sleep (SWS), and rapid eye movement (REM) were not altered. Controlling Cheyne-Stokes respiration with noninvasive pressure preset ventilation resulted in reduced arousal and improved sleep quality in the patients with congestive heart failure. Noninvasive pressure preset ventilation should be considered a potential therapy for Cheyne-Stokes respiration in congestive heart failure in those patients who do not respond or fail to tolerate nasal continuous positive airway pressure therapy.

Low-flow oxygen and bilevel ventilatory support: effects on ventilation during sleep in cystic fibrosis

We measured ventilation in all sleep stages in patients with cystic fibrosis (CF) and moderate to severe lung disease, and compared the effects of low-flow oxygen (LFO2) and bilevel ventilatory support (BVS) on ventilation and gas exchange during sleep. Thirteen subjects, age 26 +/- 5.9 yr (mean +/- 1 SD), body mass index (BMI) 20 +/- 3 kg/m2, FEV1 32 +/- 11% predicted, underwent three sleep studies breathing, in random order, room air (RA), LFO2, and BVS +/- O2 with recording of oxyhemoglobin saturation (SpO2) (%) and transcutaneous carbon dioxide (TcCO2) (mm Hg). During RA and LFO2 studies, patients wore a nasal mask with a baseline continuous positive airway pressure (CPAP) of 4 to 5 cm H2O. Minute ventilation (V I) was measured using a pneumotachograph in the circuit and was not different between wake and non-rapid eye movement (NREM) sleep on any night. However, V I was reduced on the RA and LFO2 nights from awake to rapid eye movement (REM) (p < 0.01) and from NREM to REM (p < 0.01). On the BVS night there was no significant difference in V I between NREM and REM sleep. Both BVS and LFO2 improved nocturnal SpO2, especially during REM sleep (p < 0.05). The rise in TcCO2 seen with REM sleep with both RA and LFO2 was attenuated with BVS (p < 0.05). We conclude that BVS leads to improvements in alveolar ventilation during sleep in this patient group.

An overview of nasal CPAP therapy in the management of obstructive sleep apnea

Obstructive sleep apnea is readily reversible with nasally administered continuous positive airway pressure, although its effectiveness can be limited by poor patient compliance with therapy. With recent developments in technology, the ability to both diagnose and manage this disorder is dramatically improving. Assessment and therapeutic intervention can now be carried out not only in attended settings, such as sophisticated sleep laboratories, but in semiattended and unattended situations, including the home. What impact these advances will have on improving patient tolerance to therapy and reducing long-term clinical consequences of obstructive sleep apnea remains to be seen. However, there is no doubt that sleep-trained professionals now have many more tools at their disposal to diagnose and treat this disorder.

An Overview of Nasal CPAP Therapy in the Management of Obstructive Sleep Apnea

Obstructive sleep apnea is readily reversible with nasally administered continuous positive airway pressure, although its effectiveness can be limited by poor patient compliance with therapy. With recent developments in technology, the ability to both diagnose and manage this disorder is dramatically improving. Assessment and therapeutic intervention can now be carried out not only in attended settings, such as sophisticated sleep laboratories, but in semiattended and unattended situations, including the home. What impact these advances will have on improving patient tolerance to therapy and reducing long-term clinical consequences of obstructive sleep apnea remains to be seen. However, there is no doubt that sleep-trained professionals now have many more tools at their disposal to diagnose and treat this disorder.

Breathing during sleep in patients with nocturnal desaturation

The mechanisms leading to hypoxemia during sleep in patients with respiratory failure remain poorly understood, with few studies providing a measure of minute ventilation (V I) during sleep. The aim of this study was to measure ventilation during sleep in patients with nocturnal desaturation secondary to different respiratory diseases. The 26 patients studied had diagnoses of chronic obstructive pulmonary disease (COPD) (n = 9), cystic fibrosis (CF) (n = 2), neuromusculoskeletal disease (n = 4), and obesity hypoventilation syndrome (OHS) (n = 11). Also reported are the results for seven normal subjects and seven patients with effectively treated obstructive sleep apnea (OSA) without desaturation during sleep. Ventilation was measured with a pneumotachograph attached to a nasal mask. In the treated patients with OSA and in the normal subjects, only minor alterations in V I were observed during sleep. In contrast, mean V I for the group with nocturnal desaturation decreased by 21% during non-rapid-eye-movement (NREM) sleep and by 39% during rapid-eye-movement (REM) sleep as compared with wakefulness. This reduction was due mainly to a decrease in tidal volume (V T). Hypoventilation was most pronounced during REM sleep, irrespective of the underlying disease. These data indicate that hypoventilation may be the major factor leading to hypoxia during sleep, and that reversal of hypoventilation during sleep should be a major therapeutic strategy for these patients.

Effects of long-term nocturnal nasal ventilation on spontaneous breathing during sleep in neuromuscular and chest wall disorders

Nocturnal nasal intermittent positive pressure ventilation (NIPPV) is an effective means of normalizing awake blood gases in patients with respiratory insufficiency due to neuromuscular or chest wall dysfunction. However, little attention has been paid to the effects of long-term ventilation on spontaneous breathing during sleep in such patients. The purpose of this study was to determine whether spontaneous breathing during sleep improved after long-term nasal ventilation. Fourteen patients with documented nocturnal respiratory failure, who had been treated with nocturnal NIPPV for at least 6 months, were reviewed with an all night polysomnograph on a night without ventilatory support. The severity of nocturnal desaturation both in non-rapid eye movement (NREM) and rapid eye movement (REM) sleep without nocturnal ventilation was compared to desaturation measured during the initial diagnostic study. Spontaneous daytime blood gas values (mean +/- SD) were significantly improved at follow-up compared to values obtained prior to nasal ventilation: arterial oxygen tension (Pa,O2): 7.5 +/- 1.2 to 10.2 +/- 1.3 kPa (p < 0.005); arterial carbon dioxide tension (Pa,CO2) 8.2 +/- 1.6 to 6.4 +/- 0.7 kPa (p < 0.001). Significant improvements in inspiratory muscle strength were also observed with maximal inspiratory pressure (Pl, max) increasing from a baseline value of 41 +/- 18 to 65 +/- 26% predicted measured prior to the night of ventilation withdrawal (p < 0.003). Spontaneous breathing during sleep after long-term treatment was markedly improved although still abnormal. During NREM sleep without ventilatory support, oxygen desaturation was significantly less severe compared to the initial study (arterial oxygen saturation (Sa,O2) 88 +/- 4 vs 78 +/- 8%; p < 0.001). Minimum Sa,O2 during REM sleep similarly improved from a mean value of 49 +/- 14% during the diagnostic night to 73 +/- 10% at review follow-up (p < 0.001). In 12 patients, transcutaneous carbon dioxide was measured continuously during sleep on both occasions and demonstrated significantly less CO2 retention during follow-up compared to control studies both in NREM (p < 0.003) and REM sleep states (p < 0.004). Long-term nocturnal ventilation produces improved respiratory drive both asleep and awake and improved arousal responses to abnormal blood gases.

Benefits of nocturnal nasal CPAP in patients with cystic fibrosis

Patients with cystic fibrosis (CF) often hypoventilate during sleep with marked falls in oxygen saturation (SaO2%). This occurs most commonly during REM sleep, when there is a reduction in rib cage excursion and a fall in end-expiratory lung volume (EELV). The aim of this study was to examine the effect of nocturnal nasal continuous positive airway pressure (nCPAP) on SaO2 and the respiratory disturbance index (RDI) during sleep in patients with CF and severe lung disease. Seven patients (FEV1% pred, 23 +/- 5; range, 14 to 28%) were evaluated during sleep on two nights, control and nCPAP (11 +/- 2 cm H2O; range, 8 to 16 cm H2O), with four patients breathing room air and three patients breathing supplemental oxygen on both nights. Mean awake SaO2 was 91 +/- 1% (range, 89 to 93%). All patients showed significant oxyhemoglobin desaturation and respiratory disturbance in the control study. The maximal falls in SaO2 (15 +/- 10%) were most often associated with phasic eye movements, and a decline in rib cage excursion and the sum signal (Respitrace) during REM sleep. Nasal CPAP resulted in a significant improvement in the mean minimum oxygen saturation (MMOS) during both NREM (nCPAP 91 +/- 3% vs control 88 +/- 2%, p < 0.05) and REM sleep (nCPAP 89 +/- 6% vs control 83 +/- 6%, p < 0.05). Transcutaneous CO2 measurements were not significantly different between the control and the nCPAP studies. The RDI was also significantly reduced with nCPAP especially during REM sleep (9 +/- 7 events per hour vs control 25 +/- 11 events per hour, p < 0.05). Nasal CPAP caused no change in total sleep time or sleep efficiency yet significantly reduced the RDI and improved baseline SaO2 during both NREM and REM sleep.

Effects of short-term NIPPV in the treatment of patients with severe obstructive sleep apnea and hypercapnia

Although nasal continuous positive airway pressure (CPAP) is effective in the treatment of most patients with obstructive sleep apnea (OSA), there is a small group of such patients in whom rapid eye movement (REM) hypoventilation and CO2 retention persist despite the use of CPAP and supplemental oxygen. In this report we describe our experience with nocturnal nasal ventilation (nocturnal nasal positive pressure ventilation [NIPPV] in such patients and its effectiveness in reversing daytime hypercapnia. Thirteen patients, aged 28 to 69 years, with severe OSA confirmed on polysomnography, failed to respond to initial CPAP therapy. All were grossly obese (body mass index [BMI] > 35 kg.ml-1) and hypercapnic (mean PaCO2, 62 mm Hg). Nocturnal nasal ventilation was commenced using a volume-cycled ventilator, which was well tolerated in all patients. After 7 to 18 days of NIPPV, significant improvements in daytime arterial blood gas values were achieved, with a rise in arterial oxygen tension from 50 +/- 2.6 (SEM) to 66 +/- 3 mm Hg (p < 0.001) and a fall in CO2 from 62 +/- 2.5 to 46 +/- 1 mm Hg (p < 0.0001). Nine of the 13 patients were able to be established on a regimen of nasal CPAP after this period, while 3 patients required a longer period (up to 3 months) before adequate nocturnal ventilation could be maintained. In one patient, the improvements in ventilatory drive achieved with NIPPV could not be maintained on CPAP, and she was transferred on to NIPPV long term. These results indicate that effective nasal ventilation leads to an overall improvement in spontaneous ventilation and blood gas values both awake and asleep. We believe this improvement is the result of improved central ventilatory drive. Short-term NIPPV provides lasting benefits allowing the majority of such patients to resume CPAP therapy. Short-term intervention with this therapy should be considered as an interim measure in patients with severe hypercapnic OSA who fail to respond to initial CPAP therapy.

Nocturnal nasal IPPV stabilizes patients with cystic fibrosis and hypercapnic respiratory failure

Nocturnal nasal intermittent positive pressure ventilation (nIPPV) has been used successfully in the management of patients with respiratory failure due to chest wall deformity and neuromuscular disease. In order to determine if nIPPV is useful in patients with cystic fibrosis (CF) complicated by respiratory failure, we treated four hypercapnic patients for up to 18 months. All patients had failed to respond to intensive conventional therapy, including nocturnal nasal CPAP in three of the patients. Within a few days of commencing nIPPV, all reported improved length and quality of sleep. There was lessening of the degree of hypercapnia and an increase in respiratory muscle strength. After stabilization in the hospital, all patients were able to be discharged home receiving nocturnal assisted ventilation. The improvements seen in these patients have been maintained for up to 18 months. We believe nIPPV offers an effective therapeutic approach for patients with end-stage CF in hypercapnic respiratory failure and may be particularly advantageous for those awaiting heart-lung transplant.

Sleep and respiration: Implications for pulmonary rehabilitation

Despite the growing interest in the role of the inspiratory and accessory muscles of respiration in chronic respiratory disease, few therapists have considered the role sleep may play in the deterioration of a patient's clinical condition. A number of important physiological changes to respiration occur during sleep, which affect chest wall mechanics and gas exchange. The ensuing abnormalities caused by sleep hypoventilation and fragmentation can severely affect daytime function and wellbeing. Nocturnal nasal positive pressure ventilation (NIPPV) is now established as an effective means of preventing such changes in patients with chest wall and lung disease. Therapists involved in pulmonary rehabilitation programs must recognise the potential for nocturnal respiratory events to severely affect daytime function and understand the importance of reversing nocturnal respiratory failure in order to maximise the rehabilitation potential of patients.