Evaluating noninvasive ventilation using a monitoring system coupled to a ventilator: a bench-to-bedside study.

Empirically determined noninvasive ventilation (NIV) settings may not achieve optimal ventilatory support. Some ventilators include monitoring modules to assess ventilatory quality. We conducted a bench-to-bedside study to assess the ventilatory quality of the VPAPIII-ResLink (ResMed, North Ryde, Australia). We tested the accuracy of minute ventilation (MV) and leak calculations given by VPAPIII-ResLink compared to those measured by a bench model at varied leak levels and ventilator settings. We systematically assessed NIV efficacy using this system from 2003 to 2006. Ventilation was considered inadequate if leak (>24 L x min(-1)), continuous desaturation (>30% of the trace) or desaturation dips (>3%) were present. On the bench test, both methods were highly correlated (r = 0.947, p>0.0001 and r = 0.959, p<0.0001 for leak and MV, respectively). We performed 222 assessments in 169 patients (aged 66.42+/-16 yrs, 100 males). Abnormalities were detected on 147 (66%) out of 222 occasions. Leak was the most common abnormality (34.2%) followed by desaturation dips (23.8%). The most effective therapeutic solutions were a chin strap if leak was detected (61.2%) and expiratory positive airway pressure increase for desaturation dips (59.5%). In 15.7% of cases, when abnormalities persisted, a polygraphy was performed. The systematic use of this device enables NIV to be optimised, limiting the indication of sleep studies to complex cases.

[Leak monitoring in noninvasive ventilation]. / Monitorización de las fugas en ventilación no invasiva.

Nasal mask ventilation has been shown to be effective, but outcomes do not always match expectations because of mouth leaks, patient-ventilator asynchrony, or decreased upper airway patency. These developments are detected when they lead ultimately to circuit leaks that lower the effectiveness of ventilation through pressure loss, poor inspiratory triggering, and prolonged inspiratory time. The quality of sleep is affected, and adverse effects and treatment intolerance may arise. A number of ways to detect leaks and their practical consequences are proposed in this article. We applied 310 leak-detection procedures to 177 patients who had disappointing clinical, gasometric, or polysomnographic outcomes of ventilation. The leak-detection procedures varied according to the type of ventilation and the supposed underlying pathophysiological mechanism. Significant leaks were detected in 132 patients (76%); therapeutic changes were then prescribed to optimize outcomes. We present a practical method to apply in patients with suboptimal ventilation outcomes. If leaks can be detected during treatment, the probable cause of treatment failure can sometimes be established and possible pathophysiological mechanisms better understood. With this knowledge, it may be possible to improve ventilation.

[Acute respiratory failure in obesity]. / Les décompensations respiratoires aiguës de l'obèse.

Obstructive sleep apnea, obesity-related hypoventilation - a hypoventilation which is independent of apneas and increased by sleep -, and hypoxemia related to local ventilation-perfusion disorders are the main mechanisms of respiratory failure occurring during acute respiratory decompensation following an often minimal triggering event. Non-invasive ventilation has been found to be an effective treatment, particularly with a ventilator capable of maintaining positive expiratory and pressure. The level of the expiratory positive airway pressure must be adapted to cure episodes of obstructive apnea or hypopnea. The level of the inspiratory positive airway pressure (pressure support ventilator), or the tidal volume (volume-controlled ventilator) must be adapted to correct the residual hypoventilation. These adaptations can be made by proper assessment of nocturnal SaO(2) recordings. In particularly severe cases, use of endotracheal ventilation may be necessary to control a state of shock or consciousness disorders incompatible with the patient cooperation necessary for non-invasive ventilation.

[Pathology of craniocervical junction and sleep disorders]. / Pathologies de la charnière cervicale et apnées du sommeil.

Sleep apnea is a manifestation which has recently been recognized in anomalies of craniovertebral junction. The main reported cases involve Arnold-Chiari malformation, and clinical manifestation is a central sleep apnea syndrome. The pathophysiological mechanisms of such a sleep apnea are a blunted bulbar chemical drive (in hypercapnic patients) or an increased bulbar chemical drive which destabilizes the breathing pattern during sleep (in normo/hypocapnic patients). As this sleep apnea can be the initial manifestation of a Arnold-Chiari malformation, craniocervical magnetic resonance imaging is recommended when a central sleep apnea without evident aetiology is discovered in a young patient. Other anomalies, such as bone malformations (platybasia for example) or syryngobulbomyelia can be involved. Other respiratory manifestations can be observed such as obstructive sleep apnea syndrome, diaphragmatic or vocal cord paralysis. These manifestations may be life-threatening and may lead to decompressive surgery.

Intrapulmonary artery and intrabronchial migration and extraction of a fragment of J-shaped atrial pacing catheter.

A fragment of a fractured Telectronics Atrial Accufix 330-801 lead asymptomatically perforated the adjacent bronchus and was detected on routine chest X-ray. The metallic fragment was located by chest CT scan and bronchial fluoroscopy to lie between the right lobar bronchus and the pulmonary artery, confirming bronchial perforation. The foreign body was removed without complication by direct visualisation with rigid bronchoscopy.

[Management of obesity and respiratory insufficiency. The value of dual-level pressure nasal ventilation]. / Prise en charge de l'obèse en décompensation respiratoire. Intérêt de la ventilation nasale à double niveau de pression.

Obstructive Sleep Apnea (OSA), Obesity-Linked Hypoventilation (OLH)--a hypoventilation which is independent of apneas and increased by sleep--, and COPD are mechanisms for respiratory failure in obese patients. We thought nasal bi-level positive airway pressure to be a suitable treatment: EPAP is useful to maintain upper airway patency and IPAP-EPAP difference to correct OLH and COPD hypoventilation. Our purpose is to report the results of such a therapeutic approach. We included 41 patients that we first treated by nasal bi-level positive airway pressure for a respiratory failure with an uncompensated respiratory acidosis. The initial setting was about 4 cm H2O for EPAP and 16 for IPAP. Under supervision of a real-time printed oximetry tracing, we furthermore increased EPAP until disappearance of repetitive dips in oxygen saturation (that we assimilated to obstructive events) and IPAP until obtaining an acceptable level of steady saturation (we assimilated a low level to a steady hypoventilation). Age (mean +/- SD) was 63 +/- 11 years, BMI 42 +/- 9 kg/m2, pH 7.32 +/- 0.04, PaCO2 71 +/- 13 mmHg, PaO2 45 +/- 7 mmHg. Thirty-nine out of 41 patients returned home without need for tracheal intubation. At 7 days of treatment, PaCO2 was 50 +/- 6 mmHg. Thus, nasal bi-level position airway pressure appears to be an efficient treatment in these patients.

Relative survival analysis of 252 patients with COPD receiving long-term oxygen therapy.

OBJECTIVES: A survival analysis was conducted on patients with COPD receiving long-term oxygen therapy (LTOT) to compare two different statistical methods. METHODS: We used a multivariate crude (observed) survival model (Cox) and a multivariate relative survival model (Hakulinen). Only the latter is able to correct the survival by adjusting it to the normal life expectancy of the studied patients. PATIENTS: Two hundred fifty-two hypoxemic COPD patients (207 male) requiring LTOT were included. Mean PaO2 was <50 mm Hg before oxygen therapy. Mean age was >69 years (SE: 9.9). They had severe bronchial obstruction: mean FEV1 was <33% (10.6) of predicted values, with some CO2 retention: mean PaCO2 was 45.6 (7.1) mm Hg. By December 31, 1995, 189 patients had died (75%) and 13 (5%) were unavailable for follow-up. RESULTS: The overall crude survival was poor: 80.9% after 1 year, 67.1% after 2 years, 34.7% after 5 years, and 7.1% after 10 years. In the crude multivariate analysis (Cox), the negative prognostic factors were age and hypercapnia. The overall relative survival (Hakulinen), corrected for life expectancy, was 82.8% after 1 year, 70.8% after 2 years, 41.5% after 5 years, and 10.25% after 10 years. In the final multivariate relative model, age was no longer significant and the only bad prognostic factor was hypercapnia with a relative risk of 1.97 (1.16 to 3.34). CONCLUSION: This work shows the inadequacy of the Cox observed survival model when it comes to appreciating the real prognostic impact of age, because of the confusing factor associated with a normal life expectancy.

Central sleep apnoea in Arnold-Chiari malformation: evidence of pathophysiological heterogeneity.

We report on the case of two young patients with type I Arnold-Chiari malformation (ACM), as revealed by a central sleep apnoea (CSA) syndrome without any other neurological defect. Case 1 was a 14-yr-old male patient, who developed severe alveolar hypoventilation and needed long-term mechanical ventilation via a tracheostomy. Case 2 was a 39-yr-old male patient, who developed features suggestive of sleep apnoea and responded to nasal continuous positive airway pressure ventilation despite the central type of apnoeas. These two cases illustrate the different pathophysiological mechanisms involved in CSA, namely a blunted chemical drive (in hypercapnic patients) and an increased chemical drive, which destabilizes the breathing pattern during sleep (in normo/hypocapnic patients). Central sleep apnoea can be the initial manifestation of Arnold-Chiari malformation and can lead to a life-threatening condition.

[Intrabronchial migration and extraction of a fragment of an Accufix J-shaped atrial pacing catheter]. / Migration intrabronchique et extraction d'un fragment de guide J d'une sonde auriculaire Accufix.

The authors report a case of exteriorisation and migration of a fragment of a J-shaped atrial Accufix Telectronix (Stimarec Class IV) responsible for a bronchial penetration without clinical repercussion. A systematic control chest X-ray detected this complication. The position of the metallic fragment was determined by chest CT scan and bronchial fibroscopy between the inferior right lobar bronches and artery confirming bronchial perforation. Rigid bronchoscopy with direct visualisation enabled extraction of the foreign body without complications.

Fatal ball-valve airway obstruction by an extensive blood clot during mechanical ventilation.

A ball-valve airway obstruction by a blood clot cast of almost the whole bronchial tree occurred in a small-cell lung cancer patient, who had been on mechanical ventilation for 9 days. Chest radiographs revealed overinflated lungs. Attempts to remove the cast via fibreoptic bronchoscopy were unsuccessful and the patient died. A postmortem extraction of the clot was performed with a rigid tube. This case is rare because of absence of severe haemoptysis and lung volume reduction.

Nasal intermittent positive pressure ventilation. Long-term follow-up in patients with severe chronic respiratory insufficiency.

Prior studies have shown that nasal intermittent positive pressure ventilation (NIPPV) can improve arterial blood gas values, prevent symptoms resulting from alveolar hypoventilation, and decrease hospitalization in patients with chronic respiratory failure. Most studies have involved small samples of patients followed up for a limited time. This study reviews our experience during 5 years use of NIPPV in 276 patients with kyphoscoliosis, posttuberculosis sequelae, Duchenne-type muscular dystrophy, COPD, and bronchiectasis followed up for > or = 3 years while receiving NIPPV. Outcomes were compared for patients who survived short term eg, died or converted to management with a tracheostomy and intermittent positive ventilation (TIPPV) during year 1 or year 2 on a regimen of NIPPV and long term, eg, survived more > or = 2 years on a regimen of NIPPV. The most favorable outcome was achieved by patients with kyphoscoliosis and posttuberculosis sequelae with improvement in PaO2 and PaCO2 (p < 0.0001) and a reduction in days of hospitalization for respiratory illness (p < 0.0001) for > or = 2 years while receiving NIPPV. Patients with Duchenne-type muscular dystrophy also had fewer hospital days during NIPPV (p < 0.003) but only 9 of 16 patients (56 percent) continued using NIPPV for the duration of followup. Benefit was also more short term for patients with COPD and bronchiectasis. NIPPV can sustain improvement in gas exchange, while reducing hospitalization for substantial periods of time. NIPPV can be an attractive and effective alternative to other methods of assisted ventilation such as TIPPV.

Celiprolol pneumonitis.

We report on a patient who developed hypersensitivity pneumonitis during treatment with the beta-blocker, celiprolol. The clinical picture was a severe alveolitis, with compromised gas exchange. Inadvertent subsequent rechallenge with celiprolol led to recurrence of the pneumonitis, 10 weeks after drug readministration. Again, the pneumonitis was fully reversible. Lymphocytes were elevated in bronchoalveolar lavage, and progressively normalized upon discontinuation of the drug. This case is reminiscent of pneumonitis to other beta-blockers, which are reviewed here.

[Nitrosourea-induced lung diseases]. / La pneumopathie des nitrosourées.

Nitrosoureas belong to the group of alkylating agents, and are increasingly used in the treatment of brain malignancies, due to their excellent penetration through the hemo-meningeal barrier. Since 1976, pulmonary toxicity from nitrosoureas has emerged as a significant problem, especially with BCNU, and 72 cases are available in the literature for review. While it is difficult to ascertain the exact prevalence of nitrosourea lung (estimate range between 1 and 20%), it is now clear that a direct relationship exists between cumulated exposure to the nitrosourea, and the likelihood of developing pulmonary toxicity. The clinical picture is that of a diffuse, severe fibrosis with hypoxemia. Histopathology, available in 55 reports, showed diffuse bland fibrosis. The outcome is poor with 67% of the patients dead by the time of publication. While we feel that corticosteroids should be tried for any possible beneficial effect, they seem to be of limited help.

[Reflections on the management of suspected recent pulmonary embolism]. / Réflexions sur la conduite à tenir devant une suspicion d'embolie pulmonaire récente.

Pulmonary Embolism (EP) remains a major challenge for the physician, despite increasingly sophisticated investigations and efficient therapeutic programs. Many reasons explain persistent difficulties: the disorder crosses all specialties. A wide variety of clinical presentations has to be considered according to the size of the thrombus, the coexisting conditions ("predisposing factors") and the prior cardio pulmonary status. Major investigations include perfusion and ventilation lung scans, pulmonary angiography, invasive and non invasive investigations of the deep venous system. But obvious practical limitations exist; selection of the most suitable test includes severity of the present patient condition and risk of an early recurrence of EP; risk of the contemplated therapeutic procedure if the diagnosis of EP is confirmed; skillfulness required for the selected investigation. Angiography is mandatory if a substantial hemorrhagic risk exists, if massive EP is suspected, and if at risk treatment procedures are contemplated. In the other cases, and in the absence of significant pulmonary pathology, a lung perfusion scan is the advisable procedure; the diagnosis is excluded if the scan is normal. Previous or current significant pulmonary pathology requires angiography. However, proof of coexisting deep venous thrombosis is an alternative way to enhance the diagnosis in case of poor clinical conditions or other practical considerations.

[Favorable outcome of Wegener's disease limited to the lungs. Apropos of a case]. / Evolution favorable de la maladie de Wegener limitée aux poumons. A propos d'un cas.

A case of Wegener's granuloma limited to the lungs is reported in a 22 year old man. The pulmonary radiograph showed bilateral nodules. A lung biopsy of a nodule revealed a necrosing vasculitis involving the arteries and the veins and some areas of necrosis in geographical contours around these vessels. The renal function was normal and 4 1/2 years later the outcome remains favourable with the minimum of treatment, the exception being a course of antibiotics post operatively. Fifty seven cases of Wegener's granuloma limited to the lungs have been diagnosed after lung biopsy, transbronchial or bronchial material. The outcome was favourable in 72% of cases. This result was observed in the absence of any treatment in 6 cases (13%). In 2 cases the pulmonary nodules disappeared or developed cavities. In 4 cases the anatomical and/or radiological progress is unknown. Currently the factors leading to such an outcome have not yet been identified.

[Busulfan-induced pneumopathy]. / La pneumopathie du busulfan.

Busulfan or Misulban is considered by many the treatment of choice in chronic myeloid leukemia, for which it is used as a single agent. An interstitial fibrosing lung disease occurring after Busulfan was first described in 1961 and to date 56 cases have been published and are the object of this review. The clinical picture of this drug induced disease is well characterised. The disorder has an estimated incidence of 6% and begins gradually, marked by non-specific signs (dyspnoea, cough) and by an alteration in the clinical state, often severe, and is frequently accompanied by skin pigmentation. As a rule it occurs after prolonged treatment (on average 41 months, cumulative dose 2.900 mg). The respiratory function pattern is that of an interstitial fibrosis characterised by reduced volumes and hypoxaemia and hypocapnic respiratory failure. The radiology reveals interstitial and predominantly basal shadows. The histology is often obtained, either by lung biopsy or frequently at necropsy, because the prognosis is poor with an 84% mortality from respiratory failure. As for numerous interstitial pneumopathies, it poses questions as to the pathogenesis and early detection, problems which at present are imperfectly resolved.