The use of volume-assured pressure support noninvasive ventilation in acute and chronic respiratory failure: a practical guide and literature review

Noninvasive positive pressure ventilation (NPPV) is an important tool in the management of acute and chronic respiratory failure. Traditionally, continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BPAP) have been the most commonly utilized modes for these purposes. Newer hybrid modes of NPPV, such as average volume-assured pressure support (VAPS), combine the properties of both volume- and pressure-controlled NPPV and represent another tool in the treatment of acute and chronic respiratory failure. Evidence demonstrating the superiority of VAPS over BPAP is sparse, but there have been studies that have demonstrated comparable efficacy between the two modes. The use of VAPS in acute hypercapnic respiratory failure has shown better clearance of CO2 compared to BPAP, due to its property of delivering a more assured tidal volume. This, however, did not lead to a decrease in hospital-days or improved mortality, relative to BPAP. The studies evaluating VAPS for chronic respiratory failure involve small sample sizes but have shown some promise. The benefits noted with VAPS, however, did not translate into increased survival, decreased hospitalizations or improved quality of life compared to BPAP. The limited evidence available suggests that VAPS is equally effective in treating acute and chronic respiratory failure compared to BPAP. Overall, the evidence to suggest superiority of one mode over the other is lacking. There is a need for larger studies before firm conclusions can be made.

Symptom Management and End-of-Life Care in Amyotrophic Lateral Sclerosis

The number of available symptomatic treatments has markedly enhanced the care of patients with amyotrophic lateral sclerosis (ALS). Once thought to be untreatable, patients with ALS today clearly benefit from multidisciplinary care. The impact of such care on the disease course, including rate of progression and mortality, has surpassed the treatment effects commonly sought in clinical drug trials. Unfortunately, there are few randomized controlled trials of medications or interventions addressing symptom management. In this review, the authors provide the level of evidence, when available, for each intervention that is currently considered standard of care by consensus opinion.

Respiratory Failure and Mechanical Ventilation in the Pregnant Patient

Fewer than 2% of all peripartal patients need intensive care unit admission. But due to some anatomic and physiologic changes in pregnancy, respiratory failure can be promoted. This article reviews several obstetric and nonobstetric diseases that lead to respiratory failure and the treatment of these. Furthermore, invasive and noninvasive ventilation in pregnancy is discussed and suggestions of medication during ventilation are given.

Early failure of noninvasive ventilation in chronic obstructive pulmonary disease with acute hypercapnic respiratory failure

Noninvasive ventilation (NIV) in the management of chronic obstructive pulmonary disease (COPD) patients with acute hypercapnic respiratory failure is considered a first-line therapy. However, patients who fail NIV and then require invasive mechanical ventilation have been found to have higher mortality than patients initially treated with invasive mechanical ventilation. We tried to find parameters associated with early NIV failure (need for intubation or death <24 h of starting NIV) in patients presenting to the ED with acute exacerbation of COPD. A retrospective analysis was conducted of the medical records of 218 patients with acute exacerbation of COPD visiting Asan Medical Center and managed with NIV during their stay in the ED from January 2007 to December 2013. NIV was successful in 200 (91.7%) and 18 (8.3%) had early NIV failure. Of the variables obtained before NIV treatment, heart rate (≥120/min: OR 2.5, 95% CI 1.2-7.0) and pH (7.25-7.29: OR 2.1, 95% CI 1.0-8.8; <7.25: OR 11.7, 95% CI 3.5-38.6) were significant factors associated with early NIV failure. Of the variables obtained after 1 h of NIV treatment, heart rate (≥120/min: OR 7.5, 95% CI 2.3-24.3) and pH (7.25-7.29: OR 4.7, 95% CI 1.5-15.1; <7.25: OR 20.9, 95% CI 5.4-61.2) were still significant. The presence of tachycardia and severe acidosis before NIV treatment and persistence of tachycardia and severe acidosis after 1 h of NIV treatment were associated with early NIV failure.

Acute respiratory failure in patients with hematological malignancies: outcomes according to initial ventilation strategy. A groupe de recherche respiratoire en réanimation onco-hématologique (Grrr-OH) study

BACKGROUND

In patients with hematological malignancies and acute respiratory failure (ARF), noninvasive ventilation was associated with a decreased mortality in older studies. However, mortality of intubated patients decreased in the last years. In this study, we assess outcomes in those patients according to the initial ventilation strategy.

METHODS

We performed a post hoc analysis of a prospective multicentre study of critically ill hematology patients, in 17 intensive care units in France and Belgium. Patients with hematological malignancies admitted for ARF in 2010 and 2011 and who were not intubated at admission were included in the study. A propensity score-based approach was used to assess the impact of NIV compared to oxygen only on hospital mortality.

RESULTS

Among 1011 patients admitted to ICU during the study period, 380 met inclusion criteria. Underlying diseases included lymphoid (n = 162, 42.6 %) or myeloid (n = 141, 37.1 %) diseases. ARF etiologies were pulmonary infections (n = 161, 43 %), malignant infiltration (n = 65, 17 %) or cardiac pulmonary edema (n = 40, 10 %). Mechanical ventilation was ultimately needed in 94 (24.7 %) patients, within 3 [2-5] days of ICU admission. Hospital mortality was 32 % (123 deaths). At ICU admission, 142 patients received first-line noninvasive ventilation (NIV), whereas 238 received oxygen only. Fifty-five patients in each group (NIV or oxygen only) were matched according the propensity score. NIV was not associated with decreased hospital mortality [OR 1.5 (0.62-3.65)].

CONCLUSIONS

In hematology patients with acute respiratory failure, initial treatment with NIV did not improve survival compared to oxygen only.

CLINICAL TRIAL

gov number NCT 01172132.

Nasal High-flow versus non-invasive ventilation in stable hypercapnic COPD: a preliminary report

BACKGROUND

There are no data available about effectiveness of Nasal High-flow (NHF)in chronic respiratory insufficiency.

METHODS

Eleven COPD patients with stable hypercapnia were adjusted to NHF-system with a flow of 20 l/min. After six weeks patients were switched to non-invasive ventilation (NIV) for another six weeks period.

RESULTS

NHF led to significant decreases in resting pCO2. Between the devices we found no differences in pCO2 levels.

CONCLUSIONS

NHF may thus be an alternative treatment device in stable hypercapnic COPD patients.

Facial pressure zones of an oronasal interface for noninvasive ventilation: a computer model analysis

OBJECTIVE:

To study the effects of an oronasal interface (OI) for noninvasive ventilation, using a three-dimensional (3D) computational model with the ability to simulate and evaluate the main pressure zones (PZs) of the OI on the human face.

METHODS:

We used a 3D digital model of the human face, based on a pre-established geometric model. The model simulated soft tissues, skull, and nasal cartilage. The geometric model was obtained by 3D laser scanning and post-processed for use in the model created, with the objective of separating the cushion from the frame. A computer simulation was performed to determine the pressure required in order to create the facial PZs. We obtained descriptive graphical images of the PZs and their intensity.

RESULTS:

For the graphical analyses of each face-OI model pair and their respective evaluations, we ran 21 simulations. The computer model identified several high-impact PZs in the nasal bridge and paranasal regions. The variation in soft tissue depth had a direct impact on the amount of pressure applied (438-724 cmH₂O).

CONCLUSIONS:

The computer simulation results indicate that, in patients submitted to noninvasive ventilation with an OI, the probability of skin lesion is higher in the nasal bridge and paranasal regions. This methodology could increase the applicability of biomechanical research on noninvasive ventilation interfaces, providing the information needed in order to choose the interface that best minimizes the risk of skin lesion.

Where is Noninvasive Ventilation Actually Delivered for Acute Respiratory Failure?

PURPOSE

Few studies have examined locations of noninvasive ventilation (NIV) application for acute respiratory failure (ARF). We aimed to track actual locations of NIV delivery and related outcomes.

METHODS

Observational cohort study based at 8 acute care hospitals in Massachusetts on adult patients admitted for ARF requiring ventilatory support during pre-determined time intervals.

RESULTS

Of 1225 ventilator starts, 499 were NIV; 209 (42%) in intensive care units (ICU), 185 (37%) in emergency departments (ED), 91 (18%) on general wards, and 14 (3%) in other units. Utilization (% of all ventilator starts) (1), success (2) and in-hospital mortality (3) rates for patients initiated on NIV in ICU, ED, and general and other wards were (1) 38, 36, 73, and 52%, (2) 60, 77, 68, and 93% and (3) 25, 12, 17, and 0%, respectively (p < 0.05 for all). Patients with acute-on-chronic lung disease (ACLD) and acute pulmonary edema (APE) were begun on NIV most often in EDs and patients with 'de novo' ARF and neurologic disorders most often in ICU's. Approximately 2/3 of patients begun on NIV outside of ICUs were transferred within 72 h to ICUs, wards or other units.

CONCLUSIONS

Most NIV starts occurred in ICUs and EDs but utilization rate was highest (>50%) on general wards where a fifth of NIV starts took place. Actual location depended on etiology of ARF as patients with ACLD and APE were started more often in EDs and "de novo" ARF in ICU. NIV failure and mortality rates were higher in ICUs related to the greater proportion of patients with "de novo" ARF.

Prone positioning improves oxygenation in spontaneously breathing nonintubated patients with hypoxemic acute respiratory failure: A retrospective study

PURPOSE

Prone positioning (PP) improves oxygenation and outcome of patients with acute respiratory distress syndrome undergoing invasive ventilation. We evaluated feasibility and efficacy of PP in awake, non-intubated, spontaneously breathing patients with hypoxemic acute respiratory failure (ARF).

MATERIAL AND METHODS

We retrospectively studied non-intubated subjects with hypoxemic ARF treated with PP from January 2009 to December 2014. Data were extracted from medical records. Arterial blood gas analyses, respiratory rate, and hemodynamics were retrieved 1 to 2 hours before pronation (step PRE), during PP (step PRONE), and 6 to 8 hours after resupination (step POST).

RESULTS

Fifteen non-intubated ARF patients underwent 43 PP procedures. Nine subjects were immunocompromised. Twelve subjects were discharged from hospital, while 3 died. Only 2 maneuvers were interrupted, owing to patient intolerance. No complications were documented. PP did not alter respiratory rate or hemodynamics. In the subset of procedures during which the same positive end expiratory pressure and Fio2 were utilized throughout the pronation cycle (n=18), PP improved oxygenation (Pao2/Fio2 124±50 mmHg, 187±72 mmHg, and 140±61 mmHg, during PRE, PRONE, and POST steps, respectively, P<.001), while pH and Paco2 were unchanged.

CONCLUSIONS

PP was feasible and improved oxygenation in non-intubated, spontaneously breathing patients with ARF.

Nursing and Respiratory Collaboration Prevents BiPAP-Related Pressure Ulcers

In early 2012, an increase in the incidence of BiPAP-related pressure ulcers was noted in the progressive care unit of a large pediatric facility. An interdisciplinary team of nursing and respiratory staff and leadership formed a collaborative to address the gaps in practice, recommend, and implement evidence-based interventions using a quality improvement model. Interventions included piloting new masks, changing the skin barrier from a hydrocolloid dressing to a foam dressing and using a template for better fit, including skin assessments every 4 hours as part of nursing and respiratory therapists' workflow, and implementing a notification process that included Wound Ostomy Continence Nurses, respiratory, and nursing leadership for any redness of skin noted. Weekly rounding and communication by nursing and respiratory leadership ensured consistency and sustainability of practice. Aside from implementation of interventions, the primary focus was to develop a collaborative relationship between nursing and respiratory teams for shared ownership and accountability of patients on BiPAP support. Three months after the implementation of interventions, the occurrence of BiPAP-related pressure ulcers decreased from eleven in the first three quarters to one occurrence in the fourth quarter of fiscal year (FY) 2012. In 2013, the occurrence decreased to five for the entire fiscal year. Since the end of FY 2013, there has only been one occurrence of a BiPAP-related pressure ulcer in the progressive care unit. Close collaboration between respiratory and nursing has been the primary factor in decreasing BiPAP-related pressure ulcers. An important lesson learned is that interdisciplinary collaboration leads to improved patient outcomes.

Extracorporeal carbon dioxide removal in patients with chronic obstructive pulmonary disease: a systematic review

INTRODUCTION

Extracorporeal carbon dioxide removal (ECCO2R) has been proposed for hypercapnic respiratory failure in chronic obstructive pulmonary disease (COPD) exacerbations, to avoid intubation or reduce length of invasive ventilation. Balance of risks, efficacy, and benefits of ECCO2R in patients with COPD is unclear.

METHODS

We systematically searched MEDLINE and EMBASE to identify all publications reporting use of ECCO2R in COPD. We looked at physiological and clinical efficacy. A favorable outcome was defined as prevention of intubation or successful extubation. Major and minor complications were compiled.

RESULTS

We identified 3123 citations. Ten studies (87 patients), primarily case series, met inclusion criteria. ECCO2R prevented intubation in 65/70 (93%) patients and assisted in the successful extubation of 9/17 (53%) mechanically ventilated subjects. One case-control study matching to noninvasively ventilated controls reported lower intubation rates and hospital mortality with ECCO2R that trended toward significance. Physiological data comparing pre- to post-ECCO2R changes suggest improvements for pH (0.07-0.15 higher), PaCO2 (25 mmHg lower), and respiratory rate (7 breaths/min lower), but not PaO2/FiO2. Studies reported 11 major (eight bleeds requiring blood transfusion of 2 units, and three line-related complications, including one death related to retroperitoneal bleeding) and 30 minor complications (13 bleeds, five related to anticoagulation, and nine clotting-related device malfunctions resulting in two emergent intubations).

CONCLUSION

The technique is still experimental and no randomized trial is available. Recognizing selection bias associated with case series, there still appears to be potential for benefit of ECCO2R in patients with COPD exacerbations. However, it is associated with frequent and potentially severe complications. Higher-quality studies are required to better elucidate this risk-benefit balance.

Mycobacterium fortuitum thoracic empyema: A case report and review of the literature

Mycobacterium fortuitum is a rapidly growing nontuberculous mycobacterium. This microorganism is an uncommon etiological agent of lung lesions; among lung lesions caused by M. fortuitum, thoracic empyema is particularly rare. A 61-year-old man who had been treated for chronic hypercapnic respiratory failure with noninvasive ventilation was admitted because of breathing difficulty and was found to have M. fortuitum thoracic empyema. He improved after the administration of amikacin, imipenem/cilastatin, and clarithromycin following sulfamethoxazole/trimethoprim and clarithromycin. This is the first report of M. fortuitum thoracic empyema in a patient without human immunodeficiency virus infection. The thoracic empyema may have developed via a pulmonary fistula in this case. This case highlights the fact that we must be aware of the possibility of M. fortuitum thoracic empyema, especially in patients with M. fortuitum lung infection and treatment with noninvasive ventilation. Multidrug therapy may be effective and important to the resolution of M. fortuitum thoracic empyema.

[Noninvasive ventilation for acute respiratory failure in a pulmonary department]

INTRODUCTION

Noninvasive ventilation (NIV) is considered as the first choice treatment for selected patients with acute respiratory failure (ARF), but many hospitals are forced to start NIV on medical wards.

METHODS

The aim of this retrospective study was to assess the outcomes of NIV initiated for ARF on a respiratory ward and to find the criteria predictive of failure. All patients were treated in a four-bed ward specifically dedicated to NIV. Failure of NIV was defined as the need for intubation and transfer to ICU, or death.

RESULTS

Among 105 admissions with ARF, 49 episodes needed NIV. These episodes were divided into 2 groups: PaCO2<45mmHg (10) and PaCO2>45mmHg (39). The overall failure rate of NIV and overall in-hospital mortality rate were 26.5% and 17% respectively. On multivariate analysis, SAPS II and respiratory acidosis with a pH less than 7.30 were significantly associated with failure of NIV.

CONCLUSIONS

NIV is practicable and is effective in the management of mild to moderate ARF on a respiratory ward. However, patients with respiratory acidosis and a pH less than 7.30 are at risk of NIV failure.

Success/Failure Prediction of Noninvasive Mechanical Ventilation in Intensive Care Units. Using Multiclassifiers and Feature Selection Methods

OBJECTIVES

This paper addresses the problem of decision-making in relation to the administration of noninvasive mechanical ventilation (NIMV) in intensive care units.

METHODS

Data mining methods were employed to find out the factors influencing the success/failure of NIMV and to predict its results in future patients. These artificial intelligence-based methods have not been applied in this field in spite of the good results obtained in other medical areas.

RESULTS

Feature selection methods provided the most influential variables in the success/failure of NIMV, such as NIMV hours, PaCO2 at the start, PaO2 / FiO2 ratio at the start, hematocrit at the start or PaO2 / FiO2 ratio after two hours. These methods were also used in the preprocessing step with the aim of improving the results of the classifiers. The algorithms provided the best results when the dataset used as input was the one containing the attributes selected with the CFS method.

CONCLUSIONS

Data mining methods can be successfully applied to determine the most influential factors in the success/failure of NIMV and also to predict NIMV results in future patients. The results provided by classifiers can be improved by preprocessing the data with feature selection techniques.

Evaluation of functional, autonomic and inflammatory outcomes in children with asthma

Asthma is common in childhood. This respiratory disease is characterized by persistent inflammation of the airways even when the child is not in the throes of an attack. Chronic inflammation is caused by an imbalance between pro-inflammatory and anti-inflammatory mechanisms as well as autonomic dysfunction, which plays an important role in the pathogenesis and control of this condition. The impact of these physiopathological aspects leads to inactivity and a sedentary lifestyle, which exerts an influence on functional capacity and control of the disease. The main objective of non-pharmacological therapy is the clinical control of asthma and the minimization of airway obstruction and hyperinflation during an attack. These factors can be controlled with noninvasive ventilation. The aim or the present review was to describe important neural, inflammatory and functional mechanisms that affect children with asthma.

Effectiveness and predictors of failure of noninvasive mechanical ventilation in acute respiratory failure

OBJECTIVE

To assess the effectiveness and identify predictors of failure of noninvasive ventilation.

DESIGN

A retrospective, longitudinal descriptive study was made.

SETTING

Adult patients with acute respiratory failure.

PATIENTS

A total of 410 consecutive patients with noninvasive ventilation treated in an Intensive Care Unit of a tertiary university hospital from 2006 to 2011.

PROCEDURES

Noninvasive ventilation.

MAIN VARIABLES OF INTEREST

Demographic variables and clinical and laboratory test parameters at the start and two hours after the start of noninvasive ventilation. Evolution during admission to the Unit and until hospital discharge.

RESULTS

The failure rate was 50%, with an overall mortality rate of 33%. A total of 156 patients had hypoxemic respiratory failure, 87 postextubation respiratory failure, 78 exacerbation of chronic obstructive pulmonary disease, 61 hypercapnic respiratory failure without chronic obstructive pulmonary disease, and 28 had acute pulmonary edema. The failure rates were 74%, 54%, 27%, 31% and 21%, respectively. The etiology of respiratory failure, serum bilirubin at the start, APACHEII score, radiological findings, the need for sedation to tolerate noninvasive ventilation, changes in level of consciousness, PaO2/FIO2 ratio, respiratory rate and heart rate from the start and two hours after the start of noninvasive ventilation were independently associated to failure.

CONCLUSIONS

The effectiveness of noninvasive ventilation varies according to the etiology of respiratory failure. Its use in hypoxemic respiratory failure and postextubation respiratory failure should be assessed individually. Predictors of failure could be useful to prevent delayed intubation.

Noninvasive ventilation in trauma

Trauma patients are a diverse population with heterogeneous needs for ventilatory support. This requirement depends mainly on the severity of their ventilatory dysfunction, degree of deterioration in gaseous exchange, any associated injuries, and the individual feasibility of potentially using a noninvasive ventilation approach. Noninvasive ventilation may reduce the need to intubate patients with trauma-related hypoxemia. It is well-known that these patients are at increased risk to develop hypoxemic respiratory failure which may or may not be associated with hypercapnia. Hypoxemia in these patients is due to ventilation perfusion mismatching and right to left shunt because of lung contusion, atelectasis, an inability to clear secretions as well as pneumothorax and/or hemothorax, all of which are common in trauma patients. Noninvasive ventilation has been tried in these patients in order to avoid the complications related to endotracheal intubation, mainly ventilator-associated pneumonia. The potential usefulness of noninvasive ventilation in the ventilatory management of trauma patients, though reported in various studies, has not been sufficiently investigated on a large scale. According to the British Thoracic Society guidelines, the indications and efficacy of noninvasive ventilation treatment in respiratory distress induced by trauma have thus far been inconsistent and merely received a low grade recommendation. In this review paper, we analyse and compare the results of various studies in which noninvasive ventilation was applied and discuss the role and efficacy of this ventilator modality in trauma.

Obesity Hypoventilation Syndrome

Obesity hypoventilation syndrome is a respiratory consequence of morbid obesity that is characterized by alveolar hypoventilation during sleep and wakefulness. The disorder involves a complex interaction between impaired respiratory mechanics, ventilatory drive and sleep-disordered breathing. Early diagnosis and treatment is important, because delay in treatment is associated with significant mortality and morbidity. Available treatment options include non-invasive positive airway pressure (PAP) therapies and weight loss. There is limited long-term data regarding the effectiveness of such therapies. This review outlines the current concepts of clinical presentation, diagnostic and management strategies to help identify and treat patients with obesity-hypoventilation syndromes.

Efficacy of noninvasive ventilation after planned extubation: A systematic review and meta-analysis of randomized controlled trials

The objective our meta-analysis is to update the evidence on the efficacy of noninvasive ventilation (NIV) compared with conventional oxygen therapy after planned extubation. We did a systematic literature review of database, including Pubmed, EMBASE, and Cochrane. We included randomized controlled trials comparing NIV with conventional oxygen therapy after planned extubation in medical intensive care unit (ICU) in our analysis. The results of our meta-analysis is consistent with the results of previous reviews and show that NIV decreased reintubation rate significantly as compared to conventional oxygen therapy in chronic obstructive pulmonary disease (COPD) and patients at high risk for extubation failure; COPD (RR, 0.33; 95% CI, 0.16-0.69; I2 = 0), high risk (RR, 0.47; 95% CI, 0.32-0.70; I2 = 0). However, in a mixed medical ICU population, there was no statistical difference of reintubation rate between the two groups (RR, 0.66; 95% CI, 0.25-1.73; I2 = 68%). Our study suggests that use of NIV after planned extubation significantly decreases the reintubation rate in COPD patients and patients at high risk for extubation failure, confirming the findings of previous reviews. There is no difference in the reintubation rate between the two groups in the mixed medical ICU population.

The role of noninvasive positive pressure ventilation in community-acquired pneumonia

BACKGROUND

Despite the increasing use of noninvasive positive pressure ventilation (NIV) in the treatment of critically ill patients with respiratory failure, its role in the treatment of severe community-acquired pneumonia (CAP) is controversial. The aim of this study was to assess the use of NIV in patients with CAP requiring ventilation who are admitted an intensive care unit.

METHODS

A retrospective cohort study of all consecutive patients admitted to 3 tertiary care, university-affiliated, intensive care units from January 2007 to January 2012 with the principal diagnosis of CAP and requiring positive pressure ventilation was carried out. The primary outcome was acute hospital mortality. Univariable and multivariable analysis were performed to assess the association between mode of ventilation and death as well as factors associated with failure of NIV.

RESULTS

A total of 229 patients were admitted, with 20 patients excluded from the analysis because of do-not-resuscitate orders. Fifty-six percent of patients were initially treated with NIV. Of those, 76% failed NIV and required intubation and invasive ventilation. After adjusting for confounders, no difference in mortality was seen between patients who received NIV as first-line therapy in comparison with patients who received invasive ventilation (odds ratio [OR], 1.63; 95% confidence interval [CI], 0.81-3.28; P = .17). Multivariable analysis demonstrated a trend toward increased NIV failure for the patients who had higher Acute Physiology and Chronic Health Evaluation II scores (P = .07) and vasopressor use at 2 hours after initiation of positive pressure ventilation (OR, 7.5; 95% CI, 1.8-31.3, P = .006). In an adjusted analysis, patients who failed NIV had an increased odds of death when compared with patients who were treated with invasive ventilation (OR, 2.2; 95% CI, 1.0-4.8; P = .03).

CONCLUSION

Noninvasive pressure ventilation is frequently used in CAP but is associated with high failure rates. Mortality was not improved in the group of patients who received NIV as first-line therapy despite clinical characteristics that might have suggested a more favorable prognosis. Given the high rates of NIV use, high failure rates, and the hypothesis generating nature of the data in this study, further randomized studies are needed to better delineate the role of NIV in CAP.

Noninvasive ventilation with complex critical care ventilator in the treatment of acute exacerbation of chronic obstructive pulmonary disease

OBJECTIVE

To compare the clinical effect of noninvasive positive-pressure ventilation (NIPPV), delivered via critical care ventilator or miniventilator, in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

METHODS

Prospective comparison study. Patients with AECOPD underwent NIPPV via: miniventilator with BiLevel positive airway pressure (BiPAP; Group A); critical care ventilator with pressure support ventilation and positive end expiratory pressure (PSV + PEEP; Group B); critical care ventilator with pressure-synchronized intermittent mandatory ventilation (P-SIMV)+PSV + PEEP (Group C). Physiological parameters were recorded before, during and after ventilation.

RESULTS

Patients in Group C (n = 21) showed significantly better improvements in physiological parameters (compared with pretreatment values) than those in Group B (n = 20) or Group A (n = 22).

CONCLUSION

NIPPV delivered via critical care ventilator has a better treatment effect than miniventilator NIPPV in patients with AECOPD. The use of P-SIMV + PSV + PEEP mode provides a significantly better treatment effect than PSV + PEEP alone.

Noninvasive ventilation and lung volume reduction

As parenchymal lung disease in chronic obstructive pulmonary disease becomes increasingly severe there is a diminishing prospect of drug therapies conferring clinically useful benefit. Lung volume reduction surgery is effective in patients with heterogenous upper zone emphysema and reduced exercise tolerance, and is probably underused. Rapid progress is being made in nonsurgical approaches to lung volume reduction, but use outside specialized centers cannot be recommended presently. Noninvasive ventilation given to patients with acute hypercapnic exacerbation of chronic obstructive pulmonary disease reduces mortality and morbidity, but the place of chronic non-invasive ventilatory support remains more controversial.