Ventilation For Respiratory Failure Research Articles

Science, Medicine, and the Anesthesiologist

Science, Medicine, and the Anesthesiologist

Use of continuous positive airway pressure and non-invasive ventilation for respiratory failure in an Australian aeromedical retrieval service: A retrospective case series.

The purpose of the present study was to investigate the use of respiratory support via continuous positive airway pressure (CPAP) and non-invasive ventilation (NIV) in a medical retrieval service in Queensland, Australia, with reference to transport considerations and patient safety. In this unblinded retrospective case series over a 13-month period, a clinical database was reviewed for the use of CPAP/NIV. Retrieval metrics as well as clinical data were recorded. A total of 128 patients were transferred either by rotary (80%) or fixed wing (20%). The median transport time was 65 min. The median total mission time was 3.7 h. Fifty-two percent of patients were female. The median age was 69 years and 93% had a background of cardiorespiratory disease. Sixty-five percent of patients were receiving CPAP/NIV before arrival of the retrieval team. The main diagnoses were respiratory failure (29.7%), acute pulmonary oedema (26.6%) and chronic obstructive pulmonary disease (25.8%). There were no incidences of pneumothorax, intubation in transit, vomiting, desaturation, hypotension, cardiac arrest or death. In two cases NIV was abandoned due to mask intolerance and in one case there was a decrease in Glasgow Coma Scale by 2. In no cases was there a detrimental outcome for the patient. The use of NIV and CPAP appears to have a low-risk profile in aeromedical retrieval even for prolonged periods of time in an adult population.

Prone Position Impairs Oxygen Supply-Demand Balance During Systemic Hypoxia in Rabbits

Ventilation in the prone position improves the prognosis of patients with severe acute respiratory distress syndrome (ARDS). Contraindications to ventilation in this position include unstable systemic circulation. Only a few reports exist on the effects of prone ventilation in respiratory failure on systemic circulation. This animal study compared systemic hemodynamic changes between supine and prone positions in anesthetized rabbits under acute systemic hypoxia (breathing 15% O2). Cardiac output and the systemic O2 extraction ratio increased under the hypoxia, but only in the supine group. Besides, the rate pressure product was higher in the prone group than in the supine group. This study showed that prone ventilation increases myocardial O2 consumption and suppresses compensatory mechanisms to maintain aerobic metabolism during systemic hypoxia. First of all, it will be necessary to examine the effect of prone ventilation on the O2 supply-demand balance in the ARDS model.

Indications for Non-Invasive Ventilation in Respiratory Failure.

Non-invasive ventilation (NIV) is increasingly being used to treat episodes of acute respiratory failure not only in critical care and respiratory wards, but also in emergency departments. Aim of this review is to summarize the current indications for the management of NIV for respiratory failure. Current literature about the topic was reviewed and critically reported to describe the rationale and physiologic advantages of NIV in various situations of respiratory failure. Early NIV use is commonly associated with the significant decrease in endotracheal intubation rate, the incidence of infective complications (especially ventilatory associated pneumonia), Intensive Care Units and the length of hospital stay and, in selected conditions, also in mortality rates. Severe acute exacerbation of chronic obstructive pulmonary disease (pH<7.35 and relative hypercarbia) and acute cardiogenic pulmonary oedema are the most common NIV indications; in these conditions NIV advantages are clearly documented. Not so evident are the NIV benefits in hypoxaemic respiratory failure occurring without prior chronic respiratory disease (De novo respiratory failure). One recent randomized control trial reported in hypoxaemic respiratory failure a survival benefit of high-flow nasal cannulae over standard oxygen therapy and bilevel NIV. Evidence suggests the advantages of NIV also in respiratory failure in immunocompromised patients or chest trauma patients. Use during a pandemic event has been assessed in several observational studies but remains controversial; there also is not sufficient evidence to support the use of NIV treatment in acute asthma exacerbation. NIV eliminates morbidity related to the endotracheal tube (loss of airway defense mechanism with increased risk of pneumonia) and in selected conditions (COPD exacerbation, acute cardiogenic pulmonary edema, immunosuppressed patients with pulmonary infiltrates and hypoxia) is clearly associated with a better outcome in comparison to conventional invasive ventilation. However, NIV is associated with complications, especially minor complications related to interface. Major complications like aspiration pneumonia, barotrauma and hypotension are infrequent.

Use of Noninvasive Ventilation in Respiratory Failure After Extubation During Postoperative Care in Pediatrics.

The purpose of this study was to determine the rate of failure of noninvasive ventilation (NIV) after cardiac surgery in pediatric patients with respiratory failure after extubation and to identify predictive success factors. This was a prospective cohort study of pediatric patients diagnosed with congenital heart disease who underwent heart surgery and used NIV. Data were collected from 170 patients with a median age of 2 months. No patient presented cardiorespiratory arrest nor any other complication during the use of NIV. The success rate for the use of NIV was 61.8%. Subjects were divided for analysis into successful and failed NIV groups. Statistical analysis used Chi-square, Mann–Whitney, and Student’s t tests, which were performed after univariate and multivariate logistic regression for p < 0.05. In the multivariate analysis, only the minimal pressure gradient (OR 1.45 with p = 0.007), maximum oxygen saturation (OR 0.88 with p = 0.011), and maximum fraction of inspired oxygen (FiO2) (OR 1.16 with p < 0.001) influenced NIV failure. The following variables did not present a statistical difference: extracorporeal circulation time (p = 0.669), pulmonary hypertension (p = 0.254), genetic syndrome (p = 0.342), RACHS-1 score (p = 0.097), age (p = 0.098), invasive mechanical ventilation duration (p = 0.186), and NIV duration (p = 0.804). In conclusion, NIV can be successfully used in children who, after cardiac surgery, develop respiratory failure in the 48 h following extubation. Although the use of higher pressure gradients and higher FiO2 are associated with a greater failure rate for NIV use, it was found to be generally safe.

Kidney-lung pathophysiological crosstalk: its characteristics and importance.

Crosstalk between the lung and the kidney is based on the similarities that these organs share. This is why different diseases that affect one organ can have repercussions on the other. Patients with acute kidney injury can present complications such as pulmonary edema and require mechanical ventilation in respiratory failure. This interaction occurs due to the increase in systemic immune mediators that cause inflammatory reactions, oxidative stress, and an increase in vascular permeability in the lung. With regard to lung-induced renal damage, the kidney can also be affected by chemical mediators, which are translocated into the bloodstream. Moreover, the kidneys are extremely sensitive to oxygen changes which can cause them to lose their autoregulation mechanism. In patients with acute lung injury (ALI), oxygen supply is decreased causing renal hypoxia. Besides, hypercapnia generated by ALI causes vasoconstriction in the renal vascular network and activation of the renal angiotensin aldosterone system. ALI not only can cause renal injury, but also worsening chronic obstructive pulmonary disease and obstructive sleep apnea. In conclusion, kidney-lung crosstalk is commonly present in certain pathological states, and knowing its characteristics is crucial for managing the complications which may arise from this vicious circle.

Babies who don't get better: When it's not respiratory distress syndrome

Most preterm and late preterm infants who require mechanical ventilation for respiratory failure resolve their disease process and can be extubated. A small percentage, however, continues to exhibit respiratory failure and remain ventilator dependent. There are myriad conditions that the clinician needs to consider, some of which are treatable, but some of which are lethal. Strategies for diagnosis and management are discussed herein.

A Report on Antibiotic Management of Neonatal Sepsis Caused by &lt;i&gt;Enterobacter&lt;/i&gt; spp

This is a report on a case of neonatal sepsis and clinical management with multiple antibiotic therapy in a neonatal intensive care unit (NICU) in Brazil. A preterm baby boy was born by caesarean section at 34 weeks and two days of gestation from an oligodramnious pregnancy with intrauterine growth restriction. After respiratory failure detection, the baby was intubated and placed on mechanical ventilation for respiratory failure and was shifted to NICU. Ampicillin and gentamicin were instituted empirically. Enterobacter spp-induced severe sepsis was diagnosed. Included in the antibiotic therapy were oxacycline, amikacin, cefepime, tazocin, meropen and teicoplanin. After sixty days in NICU, clinical and laboratory parameters were normalized and the baby recovered. The empirical long-term antibiotic treatment and the use of broad spectrum antibiotics, as observed in the present case, should be carefully considered in newborns admitted to NICU. Keywords: Sepsis, Newborn, Respiratory failure, Multiple antibiotic therapy

8th International conference on management and rehabilitation of chronic respiratory failure: the long summaries – Part 3

This paper summarizes the Part 3 of the proceedings of the 8th International Conference on Management and Rehabilitation of Chronic Respiratory Failure, held in Pescara, Italy, on 7 and 8 May, 2015. It summarizes the contributions from numerous experts in the field of chronic respiratory disease and chronic respiratory failure. The outline follows the temporal sequence of presentations.This paper (Part 3) presents a section regarding Moving Across the Spectrum of Care for Long-Term Ventilation (Moving Across the Spectrum of Care for Long-Term Ventilation, New Indications for Non-Invasive Ventilation, Elective Ventilation in Respiratory Failure - Can you Prevent ICU Care in Patients with COPD?, Weaning in Long-Term Acute Care Hospitals in the United States, The Difficult-to-Wean Patient: Comprehensive management, Telemonitoring in Ventilator-Dependent Patients, Ethics and Palliative Care in Critically-Ill Respiratory Patients, and Ethics and Palliative Care in Ventilator-Dependent Patients).

8th International Conference on Management and Rehabilitation of Chronic Respiratory Failure: the Long Summaries

This paper summarizes Part 1 of the proceedings of the 8th International Conference on Management and Rehabilitation of Chronic Respiratory Failure, held in Pescara, Italy, on 7 and 8 May, 2015. It summarizes the contributions from numerous experts in the field of chronic respiratory disease and chronic respiratory failure. The outline follows the temporal sequence of presentations. This paper (Part 1) includes sections regarding: Advances in Asthma and COPD Therapy (Novel Therapeutic Targets for Asthma: Proteinases, Blood Biomarker Changes in COPD Patients); The problem of Hospital Re-Admission following Discharge after the COPD Exacerbation (Characteristics of the Hospitalized COPD Patient, Reducing Hospital Readmissions Following COPD Exacerbation).&#x0D; This paper summarizes Part 2 of the proceedings of the 8th International Conference on Management and Rehabilitation of Chronic Respiratory Failure, held in Pescara, Italy, on 7 and 8 May, 2015. It summarizes the contributions from numerous experts in the field of chronic respiratory disease and chronic respiratory failure. The outline follows the temporal sequence of presentations. This paper (Part 2) includes sections regarding: Promoting Physical Activity across the Spectrum of COPD (Physical activity: definitions, measurements, and significance; Increasing Physical Activity through Pharmacotherapy in COPD); Pulmonary Rehabilitation in Critical Illness (Complex COPD with comorbidities and its impact during acute exacerbation; Collaborative Self-Management in COPD: A Double-Edged Sword?; and Pulmonary Rehabilitation in Critical Illness.&#x0D; This paper summarizes Part 3 of the proceedings of the 8th International Conference on Management and Rehabilitation of Chronic Respiratory Failure, held in Pescara, Italy, on 7 and 8 May, 2015. It summarizes the contributions from numerous experts in the field of chronic respiratory disease and chronic respiratory failure. The outline follows the temporal sequence of presentations. This paper (Part 3) presents a section regarding Moving Across the Spectrum of Care for Long-Term Ventilation (Moving Across the Spectrum of Care for Long-Term Ventilation, New Indications for Non-Invasive Ventilation, Elective Ventilation in Respiratory Failure - Can you Prevent ICU Care in Patients with COPD?, Weaning in Long-Term Acute Care Hospitals in the United States, The Difficult-to-Wean Patient: Comprehensive management, Telemonitoring in Ventilator-Dependent Patients, Ethics and Palliative Care in Critically-Ill Respiratory Patients, and Ethics and Palliative Care in Ventilator-Dependent Patients).

PP08.11 – 2891: Predictors of intensive care requirement in children with Guillain-Barré syndrome: A retrospective study

Objective Pre-emptive transfer to a tertiary centre with onsite paediatric intensive care unit (PICU) support is preferable to transfer of the decompensated child in Guillain-Barre syndrome (GBS). Our aim was to identify presenting clinical, laboratory and neurophysiological features associated with requirement for PICU in children with GBS. Methods Retrospective review of children attending our tertiary centre over an 11 year period. Inclusion criteria Documented nerve conduction study and examination by a paediatric neurologist during the acute illness with features meeting consensus case definitions for GBS or Fisher syndrome (FS). Data were collected on symptoms, examination findings, laboratory and neurophysiological investigations, PICU admission and illness course. Results 52 children met case definition for GBS; one child met case definition for FS. Median age was 4 years (range 0.6–16); 55% were female. 13 children (25%) required PICU admission and 9 (17%) required ventilation for respiratory failure for a median 7 days (range 3–22). Significant predictors of requirement for PICU were bulbar involvement (odds ratio [OR] 55.0, 95% confidence interval [CI] 3.0–996), respiratory involvement (OR 25.9, 95% CI 4.7–144), autonomic dysfunction (OR 4.8, 95% CI 1.3–18.1), hypertension (OR 11.9, 95% CI 1.9–72.4), bradycardia (OR 27.0, 95% CI 1.3–564) and loss of antigravity power in ≥1 muscle group (OR 10.6, 95% CI 2.5–44.7). Mean erythrocyte sedimentation rate was 97 mm/hr in the PICU group and 34 mm/hr in the non-PICU group (p=0.004). Other variables including CSF protein, neurophysiological parameters and rate of progression did not differ significantly between groups. Conclusion Bulbar involvement, respiratory involvement, dysautonomia, profound weakness and extreme elevation in ESR are significantly associated with requirement for PICU in GBS. Identification of these features at presentation should prompt early consideration for transfer to a tertiary centre with onsite PICU support. Slow progression of weakness is a false reassuring feature in predicting eventual requirement for PICU.

Tracheostomy

The most common indications for modern tracheostomy are prolonged ventilation for respiratory failure and airway protection following traumatic brain injury with neurologic dysfunction. For background purposes, history and facts related to early tracheostomy are provided. Thereafter, anatomy and physiology are discussed, as are other anatomical considerations, including the site of the procedures, anesthesia, and patient positioning. Counseling and informed consent are also discussed. The operative techniques are provided for emergent surgical airway (cricothyroidotomy and transtracheal needle ventilation and oxygenation) and open and percutaneous tracheostomy. Tracheostomy management is described. Complications are listed and described. Early complications include displacement, pneumomediastinum/pneumothorax, bleeding, infection, acute obstruction, and negative pressure pulmonary edema. Late complications include subglottic tracheal stenosis, tracheal granulation, vocal cord dysfunction, tracheoesophageal fistula, tracheoinnominate fistula, and tracheocutaneous fistula. This review contains 13 figures, 1 video, 2 tables, and 38 references.

The clinical efficacy of mechanical ventilation for respiratory failure in patients with severe pulmonary heart disease

Objective To investigate the the clinical efficacy of mechanical ventilation in the treatment of respiratory failure in patients with severe pulmonary heart disease.Methods 60 patients with respiratory failure scondary to severe pulmonary heart disease were divided into a study group and a control group,30 for each group.The study group received conventional therapy plus mechanical ventilation; while the control group received conventional treatment alone.Results After treatment,the indicators of arterial blood gas were markedly improved and the mean length of hospital stay was shortened in the study group,as compared with the control group.The mortality rate was significantly lower and the rate of being relieved from hospital was notably higher in the study group than in the control group (20％ vs.43.33％ and 80％ vs.56.67％,P＜0.05 for both comparisons).Conclusions Mechanical ventilation can correct hypoxemia,reduce carbon dioxide retention,and lower the mortality rate in patients with respiratory failure secondary to severe pulmonary heart disease.It is a safe,effective procedure for ventilation. Key words: Mechanical ventilation; Severe pulmonary heart disease; Respiratory failure

Breathing Intolerance Index in COPD and Obesity: A Comparative Observational Study

Background: The breathing intolerance index, BIT, a noninvasive derivation of the tension-time index of respiratory muscles, has been recently used to evaluate patients with respect to their need for noninvasive ventilation. Comparing the BIT index in different disorders with mild to moderate respiratory impairment, such as COPD and obesity, would be useful in determining differences in threshold for respiratory muscle fatigue amongst cohorts. Objectives: The purpose of this study was to compare control of ventilation and BIT in individuals with obesity, chronic obstructive pulmonary disease (COPD), and control subjects free of cardiorespiratory disorders. Because change in posture can alter respiratory load and control of ventilation, variables were assessed in two postures. Methods: We assessed 142 subjects consisting of 81 with obesity, 42 with COPD, and 19 non-smoking healthy adults. All subjects underwent evaluation of pulmonary function, control of ventilation and BIT index [(Ti/Ttot) × (Vt/FVC)] in seated and supine postures. Findings: BIT index was significantly greater in seated posture in all 3 cohorts due primarily to an increase in Vt in this position. BIT index was similar in value amongst cohorts in both postures, but tended to be higher in patients with obesity and COPD. Conclusion: While BIT index is higher in seated posture, and tends to be higher in patients with obesity and COPD as compared to control subjects, discrimination between cohorts is not found in our study because of small inter-group variations of respiratory function amongst cohorts. Thus, in clinically stable patients whose vital capacities are mild to moderately reduced, the BIT index alone cannot be recommended as a predictive guide for initiating assisted ventilation for respiratory failure. Nevertheless, because it is easy to perform, and is comfortably tolerated by patients, its potential usefulness may be in periodic measurements to monitor its increase as respiratory reserve declines.

Response to Rodriguez and Feltracco: Effectiveness of Noninvasive Ventilation: The Mystery Is in the Bottom Line

Response to Rodriguez and Feltracco: Effectiveness of Noninvasive Ventilation: The Mystery Is in the Bottom Line

Respiratory Failure in Children with Status Asthmaticus: A Review of the VPS Database

Status asthmaticus is a frequent cause of admission to a pediatric intensive care unit (ICU). Children requiring intubation and mechanical ventilation for respiratory failure during these exacerbations comprise the most severely ill population of this cohort. The purpose of this study was to use a large multicenter database to determine the incidence of respiratory failure in children with acute asthma and to characterize clinical predictors associated with its occurrence. We conducted a retrospective data analysis of pediatric asthmatic patients included in the Virtual PICU Systems (VPS) database between January 2007 and December 2008. Patients requiring mechanical ventilation with cuffed or uncuffed nasotracheal or orotracheal tubes were characterized as having respiratory failure. Three thousand three hundred eighteen children were admitted with status asthmaticus during this study period, of which 201 (6.1%) had respiratory failure. There were no differences in age, male gender, or BMI between those w...

Low Efficacy of Noninvasive Mechanical Ventilation in Respiratory Failure After Cardiac Surgery: Where Is the Mystery?

We read with interest the article by García-Delgado et al1 who reported on the use of a noninvasive mechanical ventilation (NIV) approach to treat new-onset acute respiratory failure after extubation in the postoperative period after cardiac surgery. The authors retrospectively examined the baseline characteristics of patients on NIV, the adverse events requiring NIV, and the predictive factors for NIV response.

Use of Non Invasive Ventilation in Patients with Respiratory Failure in Nepal

Non-invasive ventilation (NIV) has become an integral tool in the management of acute and chronic respiratory failure. Studies have shown that use of NIV decreases the length of hospital stay, improves symptoms and also reduces the need for invasive mechanical ventilation in patients with respiratory failure. However, NIV is not used sufficiently in our country. To find out the outcome of Non Invasive Ventilation in Respiratory failure in Nepal. Retrospective analysis of data of 28 patients in between June 2010- November 2010 was done. All the patients selected had respiratory failure. Records were analysed for documentation of clinical diagnosis. Arterial blood gases were assessed prior to, after starting and after discontinuation of NIV. The outcome of NIV and the need for domiciliary oxygen was evaluated at discharge. Thirty four patients received NIV out of which 6 were excluded from the study due to insufficient documentation. Out of these 28 patients, 27 received bi-level and one patient received Continuous Positive Airway Pressure. Mean age of patients was 66.5 years and ranged from 42-87 years. Majority (19, 79%) were from age group 60-80 years. Most common cause for the use of bi-level ventilation was chronic obstructive pulmonary disease with type 2 respiratory failure in 19 patients (67.8%). Others included obesity hypoventilation syndrome two, acute interstitial pneumonia two, cardiogenic pulmonary oedema two, Interstitial lung disease one, bronchogenic carcinoma one, and bronchiectasis one. Arterial blood gas analysis was done on admission and 12 hours or earlier after the onset of bi-level ventilation. At the time of admission, 89.3% of the patients had type 2 respiratory failure, of which 60.6% had respiratory acidosis and 67.9% of patients had pCO2 above 60 mm Hg. Arterial blood pH prior to admission ranged from 7.19 to 7.50. Twelve hours after bi-level ventilation, only 21.3% had pH <7.35 and 42.8% had pCO2 above 60 mm Hg. Non invasive ventilation was successful in 27 patients (96.4%). All patients were advised domiciliary oxygen and all patients had respiratory follow up arranged. COPD patients with type 2 respiratory failure were seen to benefit most with NIV. It is a very cost effective and safe method of treatment and should be used first in patients with COPD with type 2 respiratory failure.

Goal-Directed Therapy: New Trends and Horizons

In traumatized or critically ill patients suffering from a variety of severe illnesses, survival often depends on the successful handling of a chain of time-critical events with the ultimate goal to provide sufficient tissue oxygenation. Timely initiated goal-directed therapy (GDT) is a cornerstone in the care and treatment of these patients. Based on adequate monitoring techniques, goal-directed algorithms can facilitate the early detection of pathophysiological changes and influence therapies that may improve the clinical outcomes [1]. However, there are still many controversies regarding the application of GDT in different categories of patients [2]. Thus, a search for critical illnesses and conditions that might potentially profit from GDT may be of significant importance. In this special issue we have invited authors to submit original research and review articles elucidating the front of research and defining the optimal targets for the management and treatment of various perioperative and critically ill conditions, subsequently describing goal-oriented therapeutical interventions. The papers represent a wide spectrum of topics including early hemodynamic therapy in sepsis, perioperative monitoring, goal-directed hemodynamic optimization in cardiothoracic surgery, goal-oriented management of mechanical ventilation in respiratory failure, and important aspects of novel therapies in acute lung injury and acute respiratory distress syndrome. The publications reflect new therapeutic approaches for many critically ill patients. New targets for GDT and treatment algorithms are elucidated, such as static and dynamic preload parameters, weaning and derecruitment tests during ventilation, esophageal pressure, and other respiratory variables. The papers also reflect the limitations of current monitoring tools and therapeutic strategies and discuss the optimal indications of their use. We hope that the articles in this special issue will create new ideas of goal-directed therapies that can be evaluated for future clinical implementation. Mikhail Kirov Lars Bjertnaes Zsolt Molnar Samir Sakka

Respiratory muscle strength and muscle endurance are not affected by acute metabolic acidemia

Respiratory muscle fatigue in asthma and chronic obstructive lung disease (COPD) contributes to respiratory failure with hypercapnia, and subsequent respiratory acidosis. Therapeutic induction of acute metabolic acidosis further increases the respiratory drive and, therefore, may diminish ventilatory failure and hypercapnia. On the other hand, it is known that acute metabolic acidosis can also negatively affect (respiratory) muscle function and, therefore, could lead to a deterioration of respiratory failure. Moreover, we reasoned that the impact of metabolic acidosis on respiratory muscle strength and respiratory muscle endurance could be more pronounced in COPD patients as compared to asthma patients and healthy subjects, due to already impaired respiratory muscle function. In this study, the effect of metabolic acidosis was studied on peripheral muscle strength, peripheral muscle endurance, airway resistance, and on arterial carbon dioxide tension (PaCO(2)). Acute metabolic acidosis was induced by administration of ammonium chloride (NH(4)Cl). The effect of metabolic acidosis was studied on inspiratory and expiratory muscle strength and on respiratory muscle endurance. Effects were studied in a randomized, placebo-controlled cross-over design in 15 healthy subjects (4 male; age 33.2 +/- 11.5 years; FEV(1) 108.3 +/- 16.2% predicted), 14 asthma patients (5 male; age 48.1 +/- 16.1 years; FEV(1) 101.6 +/- 15.3% predicted), and 15 moderate to severe COPD patients (9 male; age 62.8 +/- 6.8 years; FEV(1) 50.0 +/- 11.8% predicted). An acute metabolic acidemia of BE -3.1 mmol x L(-1) was induced. Acute metabolic acidemia did not significantly affect strength or endurance of respiratory and peripheral muscles, respectively. In all subjects airway resistance was significantly decreased after induction of metabolic acidemia (mean difference -0.1 kPa x sec x L(-1) [95%-CI: -0.1 - -0.02]. In COPD patients PaCO(2) was significantly lowered during metabolic acidemia (mean difference -1.73 mmHg [-3.0 - -0.08]. In healthy subjects and in asthma patients no such effect was found. Acute metabolic acidemia did not significantly decrease respiratory or peripheral muscle strength, respectively muscle endurance in nomal subjects, asthma, or COPD patients. Metabolic acidemia significantly decreased airway resistance in asthma and COPD patients, as well as in healthy subjects. Moreover, acute metabolic acidemia slightly improved blood gas values in COPD patients. The results suggest that stimulation of ventilation in respiratory failure, by induction of metabolic acidemia will not lead to deterioration of the respiratory failure.