Acute Ventilatory Failure Research Articles

Pathophysiologie der Atemmuskelschwäche

The respiratory system consists of two parts which can be impaired independently from each other, the lungs and the respiratory pump. The latter is a complex system covering different anatomic structures: the breathing centre, the peripheral nervous system, the respiratory muscles, and the thorax. According to this complexity several underlying conditions can cause insufficiency of the respiratory pump, i. e. ventilatory failure. Disturbances of the breathing centre, different neuromuscular disorders, impairments of the mechanics, such as thoracic deformities or hyperinflation, and airway obstruction are example conditions responsible for ventilatory failure. Main characteristic of ventilatory failure is the occurrence of hypercapnia which is in contrast to pulmonary failure where diffusion disturbances typically not cause hypercapnia. Both acute and chronic ventilatory failure presenting with hypercapnia can develop. In acute ventilatory failure respiratory acidosis develops, but in chronic respiratory failure pH is normalized as a consequence of metabolic retention of bicarbonate. However, acute on chronic ventilatory failure can present with a combined picture, i. e. elevated bicarbonate levels, acidosis, and often severe hypercapnia. Clinical signs such as tachypnea, features of the underlying disease or hypercapnia are important diagnostic tools in addition to the measurement of pressures generated by the respiratory muscles. Non-invasive and widely available techniques, such as the assessment of the maximal ins- and expiratory mouth pressures (PImax, PEmax), should be used as screening instruments, but the reliability of these measurements is reduced due to the volitional character of the tests and due to the impossibility to define normal values. Inspiratory pressures can be assessed more accurately and independently from the patients' effort: with or without the insertion of oesophageal and gastric balloon catheters. However, this technique is more invasive and very complex. It is therefore restricted to centres with scientific aims.

Myotonic Dystrophy Type 1 Presenting With Ventilatory Failure

To report a series of patients with adult onset myotonic dystrophy type 1 (DM1) in whom the presenting symptom was ventilatory failure. Ventilatory failure is a common complication of DM1 and may be a presenting symptom in the setting of anesthesia or surgery, but it is not known to be a heralding manifestation. Case series. Three adults developed dyspnea leading to ventilatory failure, with no cardiac or pulmonary causes identified. Case 1 required intubation for ventilator support and was sedated with propofol. There was no clinical myotonia, and electromyography (EMG) demonstrated brief runs of myotonic discharges. Examination 3 weeks later off propofol revealed percussion myotonia, and EMG evidence of long runs of myotonic discharges. Genetic testing confirmed the diagnosis of DM1. Case 2 had cataracts and ptosis but no known diagnosis of DM and no previous neurological impairments. Case 3 was previously neurologically asymptomatic but her son had congenital DM1. The diagnosis was confirmed by EMG in cases 2 and 3, and both patients were managed with bilevel ventilation (BIPAP). Myotonic dystrophy type 1 should be considered in the differential diagnosis of acute ventilatory failure in adults.

Prolonged Invasive Ventilation Following Acute Ventilatory Failure in COPD: Weaning Results, Survival, and the Role of Noninvasive Ventilation

Prolonged Invasive Ventilation Following Acute Ventilatory Failure in COPD: Weaning Results, Survival, and the Role of Noninvasive Ventilation

Profound hypokalemia causing respiratory failure in a cat with hyperaldosteronism

AbstractObjective:Description of acute respiratory failure in a cat due to profound hypokalemia associated with primary hyperaldosteronism.Case summary:A cat was presented with weakness and paraparesis that deteriorated rapidly into acute ventilatory failure. The serum potassium concentration declined despite intravenous fluid therapy. Positive pressure ventilation was required to support ventilatory function. A functional adrenocortical adenoma was found at necropsy in conjunction with a serum aldosterone concentration of greater than 3329 pmol/L.New or unique information provided:Respiratory failure secondary to profound hypokalemia is a rare, although recognized, condition. There are few reports that focus on this aspect of respiratory failure in the veterinary literature and primary hyperaldosteronism has not been reported as a cause of respiratory failure in cats.

COPDX: an update of guidelines for the management of chronic obstructive pulmonary disease with a review of recent evidence

Long-acting beta(2) agonists are an effective and convenient treatment for chronic obstructive pulmonary disease (COPD), but do not significantly improve lung function. The long-acting anticholinergic tiotropium, which can be taken once daily, decreases exertional dyspnoea and increases endurance by reducing hyperinflation. The role in COPD of the combination of a long-acting beta(2) agonist and a glucocorticoid in a single inhaler remains unclear. The minimum duration of an effective pulmonary rehabilitation program that includes exercise training is 6 weeks. Long-term treatment with inhaled glucocorticoids may reduce the rate of decline in lung function, but the effect is small. Aminophylline should no longer be routinely used in acute exacerbations of COPD. Non-invasive positive pressure ventilation (NPPV) reduces mortality and hospital stay in patients with acute hypercapnic ventilatory failure; it is also an effective weaning strategy for patients who require intubation. Further studies are required to clarify the role of NPPV in the long-term management of stable COPD.

Prolonged Invasive Ventilation Following Acute Ventilatory Failure in COPD: Weaning Results, Survival, and the Role of Noninvasive Ventilation

Invasive ventilation for COPD has significant mortality, and weaning can be difficult. At Papworth Hospital, we provide a specialist weaning service using noninvasive ventilation (NIV) for patients requiring prolonged invasive ventilation after recovery from acute illness. We analyzed our results for patients with COPD to identify factors associated with weaning outcome and survival. A retrospective analysis was conducted of COPD patients admitted for weaning from invasive ventilation, from 1992 to 2003. Weaning success and survival were assessed. Associations were sought between these outcomes and age, sex, spirometry, arterial blood gas levels, APACHE (acute physiology and chronic health evaluation) II score, length of stay (LOS), and the use of NIV and long-term oxygen therapy. Sixty-seven patients were identified, all of whom were receiving tracheostomy ventilation on transfer to the Respiratory Support and Sleep Centre (RSSC). Sixty-four patients (95.5%) were weaned, and 62 patients survived to hospital discharge. NIV was used in weaning 40 patients and in the long term in 25 patients. Median survival was 2.5 years (interquartile range, 0.7 to 4.6 years). One-year, 2-year, and 5-year survival rates were 68%, 54%, and 25%, respectively. Long-term survival was inversely associated with age and LOS in the ICU and the RSSC. The provision of maintenance NIV after weaning was associated with better long-term survival, independent of age and LOS (hazard rate, 0.48; p = 0.03). These results demonstrate that a specialist multidisciplinary approach, including the use of NIV, can be successful in weaning most COPD patients from prolonged invasive ventilation. The data also suggest that long-term NIV may improve survival in selected patients.

Acute respiratory failure in the elderly: etiology, emergency diagnosis and prognosis

IntroductionOur objectives were to determine the causes of acute respiratory failure (ARF) in elderly patients and to assess the accuracy of the initial diagnosis by the emergency physician, and that of the prognosis.MethodIn this prospective observational study, patients were included if they were admitted to our emergency department, aged 65 years or more with dyspnea, and fulfilled at least one of the following criteria of ARF: respiratory rate at least 25 minute-1; arterial partial pressure of oxygen (PaO2) 70 mmHg or less, or peripheral oxygen saturation 92% or less in breathing room air; arterial partial pressure of CO2 (PaCO2) ≥ 45 mmHg, with pH ≤ 7.35. The final diagnoses were determined by an expert panel from the completed medical chart.ResultsA total of 514 patients (aged (mean ± standard deviation) 80 ± 9 years) were included. The main causes of ARF were cardiogenic pulmonary edema (43%), community-acquired pneumonia (35%), acute exacerbation of chronic respiratory disease (32%), pulmonary embolism (18%), and acute asthma (3%); 47% had more than two diagnoses. In-hospital mortality was 16%. A missed diagnosis in the emergency department was noted in 101 (20%) patients. The accuracy of the diagnosis of the emergency physician ranged from 0.76 for cardiogenic pulmonary edema to 0.96 for asthma. An inappropriate treatment occurred in 162 (32%) patients, and lead to a higher mortality (25% versus 11%; p < 0.001). In a multivariate analysis, inappropriate initial treatment (odds ratio 2.83, p < 0.002), hypercapnia > 45 mmHg (odds ratio 2.79, p < 0.004), clearance of creatinine < 50 ml minute-1 (odds ratio 2.37, p < 0.013), elevated NT-pro-B-type natriuretic peptide or B-type natriuretic peptide (odds ratio 2.06, p < 0.046), and clinical signs of acute ventilatory failure (odds ratio 1.98, p < 0.047) were predictive of death.ConclusionInappropriate initial treatment in the emergency room was associated with increased mortality in elderly patients with ARF.

Ventilation therapy for patients with COPD

Acute ventilatory failure in COPD is caused by impaired respiratory mechanics and an imbalance of capacity and load of the respiratory muscles. Continuous positive airway pressure (CPAP), pressure support ventilation (PSV), proportional assist ventilation (PAV) or controlled mechanical ventilation (CMV) are effective in unloading the respiratory pump. CPAP reduces the inspiratory pressure time product by reducing the elastic work of breathing due to intrinsic PEEP (PEEPi). PSV and PAV reduce the work of breathing and additionally improve alveolar ventilation and CO2 elimination. In spontaneous breathing patients these modes of ventilation should be applied non invasively by using a face mask. In CMV, hyperinflation should be avoided by choice of low tidal volumes and long exspiratory times (low respiratory rate, I:E ratio 1:3, 1:4). In the weaning from CMV, PSV or PAV and CPAP is used. There seems to be a beneficial effect in nocturnal intermittent nonivasive ventilation (NPPV) in chronic hypercapnic stable COPD patients with documented hypoventilation during the night, which is reversible by NPPV.

A chart of failure risk for noninvasive ventilation in patients with COPD exacerbation

Knowing the likelihood of failure of noninvasive positive pressure ventilation (NPPV) in patients with exacerbation of chronic obstructive pulmonary disease (COPD) could indicate the best choice between NPPV and endotracheal intubation instituted earlier. For this purpose, two risk charts were designed (at admission and after 2 h of NPPV) that included all relevant measurable clinical prognostic indicators derived from a population representing the patients seen routinely in clinical practice. Risk stratification of NPPV failure was assessed in 1,033 consecutive patients admitted to experienced hospital units, including two intensive care units, six respiratory intermediate care units, and five general wards. NPPV was successful in 797 patients. Patients with a Glasgow Coma Score <11, acute physiology and chronic health evaluation (APACHE) II > or =29, respiratory rate > or =30 breaths x min(-1) and pH at admission <7.25 have a predicted risk of failure >70%. A pH <7.25 after 2 h greatly increases the risk (>90%). The risk charts were validated on an independent group of 145 consecutive COPD patients treated with NPPV due to an acute ventilatory failure episode. To identify patients with a probability of failure >50%, the sensitivity and specificity were 33% and 96.7% on admission and 52.9% and 94.1% after 2 h of NPPV, respectively. The prediction chart, based on data from the current study, can function as a simple tool to predict the risk of failure of noninvasive positive pressure ventilation and thus improve clinical management of patients tailoring medical intervention.

Effects of Inhaled Fenoterol and Positive End-Expiratory Pressure on the Respiratory Mechanics of Patients with Chronic Obstructive Pulmonary Disease

During acute ventilatory failure in patients with chronic obstructive pulmonary disease (COPD), applying external positive end-expiratory pressure (PEEPe) will reopen small airways and, thus, may enhance peripheral deposition as well as the physiological effects of inhaled beta-2 agonists. To investigate the efficacy of inhaled fenoterol applied by zero end-expiratory pressure (ZEEPe) or PEEPe. Ten patients with COPD who were intubated and mechanically ventilated received fenoterol (10 mg/4 mL) via the ventilator using a jet nebulizer for 30 min on ZEEPe and PEEPe set at 80% of the total PEEP in a random order. The total resistance of the respiratory system (rapid airway occlusion technique), change in end-expiratory lung volume and expiratory flow limitation were assessed before and 5 min, 15 min, 30 min, 60 min and 240 min after fenoterol inhalation. Before inhalation and 60 min after inhalation, the total PEEP, the change in end-expiratory lung volume and the total resistance of the respiratory system were 8+/-3 cmH2O and 6+/-3 cmH2O, 0.61+/-0.34 L and 0.43+/-0.32 L, and 26+/-7 cmH2O/L/s and 23+/-6 cmH2O/L/s, respectively, with ZEEPe, and 9+/-3 cmH2O and 8+/-3 cmH2O (P<0.05 versus ZEEPe), 0.62+/-0.34 L and 0.62+/-0.37 L (P<0.05 versus ZEEPe), and 26+/-9 H2O/L/s and 25+/-9 H2O/L/s, respectively, with PEEPe. Three patients became not flow-limited under the combination of PEEPe and fenoterol. In patients with COPD, fenoterol combined with PEEPe has opposing effects on respiratory mechanics. First, it does not significantly reduce lung hyperinflation or inspiratory resistances. Second, it allows expiratory flow limitation reversal in some patients. These findings result from the net effect on end-expiratory lung volume of each intervention. This implies that if fenoterol is used in combination with PEEPe, the level of PEEPe should be reassessed during the time course of the drug to prevent any further lung hyperinflation.

Clinical practice guideline for the use of noninvasive positive pressure ventilation in COPD patients with acute respiratory failure

Noninvasive positive pressure ventilation has been demonstrated to be of benefit in preventing endotracheal intubation and reducing mortality in specific patients in the setting of acute exacerbations of chronic obstructive pulmonary disease. The successful application of noninvasive positive pressure ventilation depends on a multitude of factors, including patient selection, choice of interface, physician experience, and patient-ventilator synchrony. The use of clinical practice guidelines has been shown to improve the process and outcomes of care. This paper presents a guideline for the use of noninvasive positive pressure ventilation in the setting of acute ventilatory failure in patients with acute exacerbations of chronic obstructive pulmonary disease.

Trichinosis as an Unusual Cause of Respiratory Failure of Neuromuscular Origin: Case Report and Review of the Literature

In Brief Hypercapnic respiratory failure due to muscle weakness secondary to polymyositis (PM) is quite exceptional in the intensive care setting. We draw attention to the presentation of a case of trichinosis manifested by severe muscle weakness that was attributed to PM refractory to the steroid treatment. There are a few reported cases of acute ventilatory failure and mechanical ventilation due to myopathic disorders. This group of diseases includes muscular dystrophies, periodic paralysis, and polymyositis (PM). The relationship between infectious agents and chronic inflammatory myositis is not clear. This paper provides a review of trichinosis based on a case of respiratory failure due to polymyositis refractory to steroid treatment.

Infrastructure, funding and follow-up in a programme of noninvasive ventilation.

Originating from centres charged with the care of patients with chronic respiratory insufficiency, noninvasive ventilation (NIV) has been used increasingly in chronic and acute respiratory failure during the last decade. Despite a considerable number of series and randomised studies advocating access to NIV for units that treat acute or chronic ventilatory failure, the number of units and the proportion of total ventilatory support remains poor. This is due to lack of education, as many units treat only a few patients per year. Indication, technique, education, monitoring and home care require special experience and a special environment and there is a wide range throughout Europe. With respect to home care in particular, there are many organisations, which range from totally private to hospital based or run for profit. A concerted action, funded by the European Union, will soon provide valuable information about the practice of home ventilation in Europe based on a European survey.

Insuficiencia respiratoria aguda como forma de debut de síndrome de Lambert-Eaton asociado a carcinoma pulmonar de células pequeñas

The Lambert-Eaton myasthenic syndrome is a rare disorder of neuromuscular transmission, usually presenting as a paraneoplastic process associated with a small cell lung cancer. Recently, respiratory muscular impairment has been described in these patients. Acute respiratory failure as a presenting symptom has been reported in few cases. We present a case of acute ventilatory failure as the first manifestation of Lambert-Eaton myasthenic syndrome associated with small cell lung cancer and discuss the main features of this disease, including its treatment. The Lambert-Eaton myasthenic syndrome should be considered in cases of unexplained acute respiratory failure and clinical evidence of neoplasic disease. We thought that electromyographic studies could reveal the real involvement of respiratory muscles, including diaphragm, in this condition.

Tracheal Compression by the Stomach Following Gastric Pull-Up: Diagnosis With CT and Treatment With Expandable Metallic Stent Placement

Surgical treatment of recurrent achalasia includes esophagectomy with gastric pull-up. A MEDLINE search yielded no articles describing an adverse effect of this surgery on pulmonary function. We report the first case of acute ventilatory failure caused by gastric pull-up. An evaluation by flexible bronchoscopy, spirometry with flow-volume loops, and dynamic CT scanning revealed extrinsic compression of the trachea by the stomach causing obstruction. Endotracheal placement of a self- expanding stent resulted in the rapid extubation of the patient with normalization of the flow-volume loop and dramatic improvement in the FVC, FEV(1), and peak expiratory flow.

Respiratory muscle involvement in multiple sclerosis.

Respiratory complications are common in the terminal stages of multiple sclerosis and contribute to mortality in these patients. When respiratory motor pathways are involved, respiratory muscle weakness frequently occurs. Although it is well established that weakness of the respiratory muscles produces a restrictive ventilatory defect, the degree of muscle weakness and pulmonary function are poorly related. Respiratory muscle weakness was observed in patients with normal or near normal pulmonary function. Expiratory muscle weakness is more prominent than inspiratory muscle weakness and may impair performance of coughing. Subsequently, in addition to bulbar dysfunction, respiratory muscle weakness may contribute to ineffective coughing, pneumonia, and sometimes even acute ventilatory failure may ensue. Respiratory muscle weakness may also occur early in the course of the disease. Recent studies suggest that the respiratory muscles can be trained for both strength and endurance in multiple sclerosis patients. Whether respiratory muscle training delays the development of respiratory dysfunction and subsequently improves exercise capacity and cough efficacy, prevents pulmonary complications or prolongs survival in the long-term remains to be determined.

Haemodynamic response during initiation of non-invasive positive pressure ventilation in COPD patients with acute ventilatory failure

The aim of this study was to check non-invasively the acute haemodynamic effects of non-invasive positive pressure ventilation (NPPV) initiation in patients with chronic obstructive pulmonary disease (COPD) and acute ventilatory failure (AVF). Nineteen consecutive COPD patients with AVF were evaluated clinically and echocardiographically during spontaneous breathing with O 2 supplementation and during NPPV plus O 2. NPPV was administered with a scheduled inspiratory pressure of 15 cmH 2O and an expiratory pressure of 4 cmH 2O, via facial mask. Arterial blood gas improved significantly (pH and PaCO 2; P<0·001) during NPPV administration in all patients; none had hypotension or acute arrhythmia. Doppler echocardiographic evaluation was feasible in most of the patients ( 16 18 ). With reference to baseline values, no significant changes in pulmonary artery pressures and cardiac output (CO) were observed by Doppler echocardiography in most patients. Only four patients (21%) showed a significant reduction (>15%) of CO during NPPV. No correlation was found between decreased CO and baseline data, but three patients showing CO reduction had poor tolerance to mask ventilation and did not improve respiratory rate during NPPV. It was concluded that the initiation of NPPV by facial mask does not alter haemodynamics acutely in most COPD patients with AVF, but individual patients may experience reduction in CO in spite of adequate oxygen saturation levels. This suggests that caution should be used when applying pre-determined and fixed pressures during NPPV. Monitoring haemodynamics by Doppler echocardiography may be useful for early detection of haemodynamic alterations due to NPPV application in patients with AVF.

Comparison of the usefulness of non-invasive ventilation between acute ventilatory failure and oxygenation failure

Objective: To compare the applicability and effect of non-invasive ventilation (NIV) between acute ventilatory failure and oxygenation failure, and to describe variables that may be related with successful outcome of NIV in each type of respiratory failure. Design: Prospective clinical study in two distinct types of respiratory failure. Setting: Medical intensive care unit of a university-affiliated hospital. Patients: Twenty-six episodes of respiratory failure managed using NIV from a total of 106 episodes in 102 patients. Respiratory failure was defined as acute ventilatory failure (VF: PaCO2 ≥43 mmHg [5.7 kPa] with pH &lt;7.35, n=19) or acute oxygenation failure (OF: PaO2/FiO2 &lt;300 mmHg [40 kPa] with pH ≥7.35, n=87) necessitating mechanical ventilation. Interventions: The subjects were managed by NIV via face mask if they fulfilled the minimal requirement for NIV application. Respiratory pattern, arterial blood gases, complications and success rate of NIV were analysed in each group. Results: Eleven of 19 (57.9%) VF cases (M:F 7:4, 55.4±14.6 years) and 15 of 87 (17.2%) OF cases (M:F 12:3, 50.6±15.6 years) were suitable for a trial of NIV (p=0.017). Nine of 11 (81.8%) VF patients and six of 15 (40%) OF patients were successfully managed on NIV and were weaned from mechanical ventilation (p=0.051). In VF, NIV resulted in a significant reduction in respiratory rate at 12 hours (p=0.045), and significant improvements in PaCO2 and pH at 24 hours (p&lt;0.05) compared to the baseline. In OF, the PaO2/FiO2 ratio improved significantly at 0.5 hour (p&lt;0.05) in patients successfully managed with NIV. Conclusions: Non-invasive ventilation was more suitable for ventilatory failure than for oxygenation failure in terms of both applicability and success rate. For hypercapnic respiratory failure, a reduction in respiratory rate with NIV heralded the improvement in blood gases. NIV was less effective for hypoxaemic respiratory failure; an immediate (30-minute) improvement in PaO2/FiO2 ratio after its application was a predictor of success in this group.

Comparison of the usefulness of non-invasive ventilation between acute ventilatory failure and oxygenation failure

Objective: To compare the applicability and effect of non-invasive ventilation (NIV) between acute ventilatory failure and oxygenation failure, and to describe variables that may be related with successful outcome of NIV in each type of respiratory failure. Design: Prospective clinical study in two distinct types of respiratory failure. Setting: Medical intensive care unit of a university-affiliated hospital. Patients: Twenty-six episodes of respiratory failure managed using NIV from a total of 106 episodes in 102 patients. Respiratory failure was defined as acute ventilatory failure (VF: PaCO2 ≥43 mmHg [5.7 kPa] with pH <7.35, n=19) or acute oxygenation failure (OF: PaO2/FiO2 <300 mmHg [40 kPa] with pH ≥7.35, n=87) necessitating mechanical ventilation. Interventions: The subjects were managed by NIV via face mask if they fulfilled the minimal requirement for NIV application. Respiratory pattern, arterial blood gases, complications and success rate of NIV were analysed in each group. Results: Eleven...

Anesthetic and surgical complications in 219 cases of myotonic dystrophy.

The objective of this study was to assess the frequency, type, and severity of perioperative complications after a first surgery under general anesthesia in patients with myotonic dystrophy (DM) and to measure the association with suspected risk factors. Numerous cases of perioperative complications in DM patients have been reported. Hazards have been associated with the use of thiopentone, suxamethonium, neostigmine, and halothane. A retrospective study of perioperative complications was conducted for 219 DM patients who had their first surgery under general anesthesia at the Chicoutimi Hospital. The overall frequency of complications was 8.2% (18 of 219). Most complications (16 of 18) were pulmonary, including five patients with acute ventilatory failure necessitating ventilatory support, four patients with atelectasis, and three patients with pneumonia. Using multivariate analysis, we found that the risk of perioperative pulmonary complications (PPC) was significantly higher after an upper abdominal surgery (odds ratio (OR), 24.4; 95% CI, 4.0 to 149.3) and for patients with a severe muscular disability, as assessed by the presence of proximal limb weakness (OR, 14.1; 95% CI, 1.5 to 134.4). The likelihood of PPC was not related to any specific anesthetic drug. Because of the increased risk of PPC, careful monitoring during the early postoperative period, protection of upper airways, chest physiotherapy, and incentive spirometry are mandatory in all symptomatic DM patients, particularly those with a severe muscular disability or those who have undergone an upper abdominal surgery.