Effectiveness of noninvasive positive pressure ventilation in the treatment of acute respiratory failure in severe acute respiratory syndrome

OBJECTIVES

To study the effectiveness of noninvasive positive pressure ventilation (NIPPV) in the treatment of acute respiratory failure (ARF) in severe acute respiratory syndrome (SARS), and the associated infection risk.

METHODS

All patients with the diagnosis of probable SARS admitted to a regional hospital in Hong Kong from March 9 to April 28, 2003, and who had SARS-related respiratory distress complications were recruited for NIPPV usage. The health status of all health-care workers working in the NIPPV wards was closely monitored, and consent was obtained to check serum for coronavirus serology. Patient outcomes and the risk of SARS transmission to health-care workers were assessed.

RESULTS

NIPPV was applied to 20 patients (11 male patients) with ARF secondary to SARS. Mean age was 51.4 years, and mean acute physiology and chronic health evaluation II score was 5.35. Coronavirus serology was positive in 95% (19 of 20 patients). NIPPV was started 9.6 days (mean) from symptom onset, and mean duration of NIPPV usage was 84.3 h. Endotracheal intubation was avoided in 14 patients (70%), in whom the length of ICU stay was shorter (3.1 days vs 21.3 days, p < 0.001) and the chest radiography score within 24 h of NIPPV was lower (15.1 vs 22.5, p = 0.005) compared to intubated patients. Intubation avoidance was predicted by a marked reduction in respiratory rate (9.2 breaths/min) and supplemental oxygen requirement (3.1 L/min) within 24 h of NIPPV. Complications were few and reversible. There were no infections among the 105 health-care workers caring for the patients receiving NIPPV.

CONCLUSIONS

NIPPV was effective in the treatment of ARF in the patients with SARS studied, and its use was safe for health-care workers.

Efficacy of noninvasive respiratory support modes for primary respiratory support in preterm neonates with respiratory distress syndrome: Systematic review and network meta-analysis

OBJECTIVES

To compare the efficacy of different noninvasive respiratory support (NRS) modes for primary respiratory support of preterm infants with respiratory distress syndrome (RDS).

DESIGN

Systematic review and network meta-analysis using the Bayesian random-effects approach. MEDLINE, EMBASE, and CENTRAL were searched.

INTERVENTIONS

High flow nasal cannula (HFNC), continuous positive airway pressure (CPAP), bilevel CPAP (BiPAP), noninvasive positive pressure ventilation (NIPPV).

MAIN OUTCOME MEASURES

Requirement of invasive mechanical ventilation (MV), any treatment failure.

RESULTS

A total of 35 studies including 4078 neonates were included. NIPPV was more effective in decreasing the requirement of MV than CPAP (risk ratios [95% credible interval]: 0.60 [0.44, 0.77]) and HFNC [0.66 (0.43, 0.97)]. Surface under the cumulative ranking curve (SUCRA) for NIPPV, BiPAP, HFNC, and CPAP were 0.95, 0.59, 0.32, and 0.13. For the outcome of treatment failure, both NIPPV and BiPAP were more efficacious compared to CPAP and HFNC (0.56 [0.44, 0.71] {NIPPV vs CPAP}, 0.69 [0.51, 0.93] {BiPAP vs CPAP}, 0.42 [0.30, 0.63] {NIPPV vs HFNC}, 0.53 [0.35, 0.81] {BiPAP vs HFNC}). The SUCRA for NIPPV, BiPAP, CPAP, and HFNC were 0.96, 0.70, 0.32, and 0.01. NIPPV was associated with a reduced risk of air leak compared to BiPAP and CPAP (0.36 [0.16, 0.73]; 0.54 [0.30, 0.87], respectively). NIPPV resulted in lesser incidence of bronchopulmonary dysplasia or mortality when compared to CPAP (0.74 [0.52, 0.98]). Nasal injury was lesser with HFNC compared to CPAP (0.15 [0.01, 0.60]).

CONCLUSIONS

Most effective primary mode of NRS in preterm neonates with RDS was NIPPV.

Improving the lung delivery of nasally administered aerosols during noninvasive ventilation-an application of enhanced condensational growth (ECG)

BACKGROUND

Aerosol drug delivery during noninvasive ventilation (NIV) is known to be inefficient due to high depositional losses. To improve drug delivery efficiency, the concept of enhanced condensational growth (ECG) was recently proposed in which a submicrometer or nanoaerosol reduces extrathoracic deposition and subsequent droplet size increase promotes lung retention. The objective of this study was to provide proof-of-concept that the ECG approach could improve lung delivery of nasally administered aerosols under conditions consistent with NIV.

METHODS

Aerosol deposition and size increase were evaluated in an adult nose-mouth-throat (NMT) replica geometry using both in vitro experiments and CFD simulations. For the ECG delivery approach, separate streams of a submicrometer aerosol and warm (39°C) saturated air were generated and delivered to the right and left nostril inlets, respectively. A control case was also considered in which an aerosol with a mass median aerodynamic diameter (MMAD) of 4.67 μm was delivered to the model.

RESULTS

In vitro experiments showed that the ECG approach significantly reduced the drug deposition fraction in the NMT geometry compared with the control case [14.8 (1.83)%-ECG vs. 72.6 (3.7)%-control]. Aerosol size increased from an initial MMAD of 900 nm to a size of approximately 2 μm at the exit of the NMT geometry. Results of the CFD model were generally in good agreement with the experimental findings. Based on CFD predictions, increasing the delivery temperature of the aerosol stream from 21 to 35°C under ECG conditions further reduced the total NMT drug deposition to 5% and maintained aerosol growth by ECG to approximately 2 μm.

CONCLUSIONS

Application of the ECG approach may significantly improve the delivery of pharmaceutical aerosols during NIV and may open the door for using the nasal route to routinely deliver pulmonary medications.

The genetics of congenital central hypoventilation syndrome: clinical implications

Congenital central hypoventilation syndrome (CCHS) is a rare genetic disorder of the autonomic nervous system (ANS) and respiratory control. This disorder, formerly referred to as Ondine’s curse, is due to a mutation in the PHOX2B gene that affects the development of the neural crest cells. CCHS has an autosomal dominant pattern of inheritance. Majority of the patients have a polyalanine repeat mutation (PARM) of the PHOX2B, while a small group has non-PARM (NPARM). Knowledge of the patient’s PHOX2B gene mutation helps predict a patient’s clinical presentation and outcome and aids in anticipatory management of the respiratory and ANS dysfunction.

Noninvasive positive pressure ventilation in acute respiratory failure due to COPD vs other causes: effectiveness and predictors of failure in a respiratory ICU in North India

OBJECTIVES

To determine the effectiveness of noninvasive positive pressure ventilation (NIPPV), and the factors predicting failure of NIPPV in acute respiratory failure (ARF) due to chronic obstructive pulmonary disease (COPD) versus other causes of ARF.

PATIENTS AND METHODS

This was a prospective observational study and all patients with ARF requiring NIPPV over a one-and-a-half year period were enrolled in the study. We recorded the etiology of ARF and prospectively collected the data for heart rate, respiratory rate, arterial blood gases (pH, partial pressure of oxygen in the arterial blood [PaO2], partial pressure of carbon dioxide in arterial blood [PaCO2]) at baseline, one and four hours. The patients were further classified into two groups based on the etiology of ARF as COPD-ARF and ARF due to other causes. The primary outcome was the need for endotracheal intubation during the intensive care unit (ICU) stay.

RESULTS

During the study period, 248 patients were admitted in the ICU and of these 63 (25.4%; 24, COPD-ARF, 39, ARF due to other causes; 40 male and 23 female patients; mean [standard deviation] age of 45.7 [16.6] years) patients were initiated on NIPPV. Patients with ARF secondary to COPD were older, had higher APACHE II scores, lower respiratory rates, lower pH and higher PaCO2 levels compared to other causes of ARF. After one hour there was a significant decrease in respiratory rate and heart rate and decline in PaCO2 levels with increase in pH and PaO2 levels in patients successfully managed with NIPPV. However, there was no difference in improvement of clinical and blood gas parameters between the two groups except the rate of decline of pH at one and four hours and PaCO2 at one hour which was significantly faster in the COPD group. NIPPV failures were significantly higher in ARF due to other causes (15/39) than in ARF-COPD (3/24) (p = 0.03). The mean ICU and hospital stay and the hospital mortality were similar in the two groups. In the multivariate logistic regression model (after adjusting for gender, APACHE II scores and improvement in respiratory rate, pH, PaO2 and PaCO2 at one hour) only the etiology of ARF, ie, ARF-COPD, was associated with a decreased risk of NIPPV failure (odds ratio 0.23; 95% confidence interval, 0.58-0.9).

CONCLUSIONS

NIPPV is more effective in preventing endotracheal intubation in ARF due to COPD than other causes, and the etiology of ARF is an important predictor of NIPPV failure.

Home noninvasive positive pressure ventilation with built-in software in stable hypercapnic COPD: a short-term prospective, multicenter, randomized, controlled trial

Background

The benefits of noninvasive positive pressure ventilation (NPPV) in patients with hypercapnic COPD are controversial. It is presumed that methodology and appropriate use of NIV ventilator might be crucial for the outcomes. With the new built-in software, the performance of NIV can be monitored at home, which can guarantee the compliance and appropriate use. This study investigated effects of home use of NIV in hypercapnia in COPD patients using the NIV ventilator with built-in software for monitoring.

Methods

The current multicenter prospective, randomized, controlled trial enrolled patients with stable GOLD stages III and IV hypercapnic COPD. Patients were randomly assigned via a computer-generated randomization sequence, with a block size of four patients, to continue optimized treatment (control group) or to receive additional NPPV (intervention group) for 3 months. The primary outcome was arterial carbon dioxide pressure (PaCO₂). Data were derived from built-in software and analyzed every 4 weeks. Analysis was carried out with the intention to treat. This study is registered with ClinicalTrials.gov, number NCT02499718.

Results

Patients were recruited from 20 respiratory units in China from October 1, 2015, and recruitment was terminated with a record of the vital statistics on May 31, 2016. A total of 115 patients were randomly assigned to the NPPV group (n=57) or the control group (n=58). Patients complied well with NPPV therapy (mean [± standard deviation] day use 5.6±1.4 h). The mean estimation of leaks was 37.99±13.71 L/min. The changes in PaCO₂ (−10.41±0.97 vs −4.32±0.68 mmHg, P=0.03) and 6-min walk distance (6MWD) (38.2% vs 18.2%, P=0.02) were statistically significant in the NPPV group versus the control group. COPD assessment test (CAT) showed a positive trend (P=0.06) in favor of the NPPV group. Pulmonary function and dyspnea were not different between groups.

Conclusion

Ventilators equipped with built-in software provided methodology for monitoring NIV use at home, which could facilitate the improvement of compliance and quality control of NIV use. It was shown that three months use of NIV at home could reduce the PaCO₂ and improve exercise tolerance (6MWD) in chronic hypercapnic COPD patients.

Aerosol Drug Delivery During Noninvasive Positive Pressure Ventilation: Effects of Intersubject Variability and Excipient Enhanced Growth

BACKGROUND

Nebulized aerosol drug delivery during the administration of noninvasive positive pressure ventilation (NPPV) is commonly implemented. While studies have shown improved patient outcomes for this therapeutic approach, aerosol delivery efficiency is reported to be low with high variability in lung-deposited dose. Excipient enhanced growth (EEG) aerosol delivery is a newly proposed technique that may improve drug delivery efficiency and reduce intersubject aerosol delivery variability when coupled with NPPV.

MATERIALS AND METHODS

A combined approach using in vitro experiments and computational fluid dynamics (CFD) was used to characterize aerosol delivery efficiency during NPPV in two new nasal cavity models that include face mask interfaces. Mesh nebulizer and in-line dry powder inhaler (DPI) sources of conventional and EEG aerosols were both considered.

RESULTS

Based on validated steady-state CFD predictions, EEG aerosol delivery improved lung penetration fraction (PF) values by factors ranging from 1.3 to 6.4 compared with conventional-sized aerosols. Furthermore, intersubject variability in lung PF was very high for conventional aerosol sizes (relative differences between subjects in the range of 54.5%-134.3%) and was reduced by an order of magnitude with the EEG approach (relative differences between subjects in the range of 5.5%-17.4%). Realistic in vitro experiments of cyclic NPPV demonstrated similar trends in lung delivery to those observed with the steady-state simulations, but with lower lung delivery efficiencies. Reaching the lung delivery efficiencies reported with the steady-state simulations of 80%-90% will require synchronization of aerosol administration during inspiration and reducing the size of the EEG aerosol delivery unit.

CONCLUSIONS

The EEG approach enabled high-efficiency lung delivery of aerosols administered during NPPV and reduced intersubject aerosol delivery variability by an order of magnitude. Use of an in-line DPI device that connects to the NPPV mask appears to be a convenient method to rapidly administer an EEG aerosol and synchronize the delivery with inspiration.

Efficacy of long-term noninvasive positive pressure ventilation in stable hypercapnic COPD patients with respiratory failure: a meta-analysis of randomized controlled trials

INTRODUCTION

The efficacy of long-term noninvasive positive pressure ventilation (NPPV) in stable hypercapnic COPD patients with respiratory failure remains unclear. The aim of this meta-analysis was to critically assess the efficacy of long-term NPPV on mortality, acute exacerbation, exercise capacity, symptoms and significant physiological parameters (lung function, respiratory muscle function and gas exchange).

PATIENTS AND METHODS

We performed an electronic literature search using the PubMed, Cochrane Library, Embase, OVID and Chinese Biomedical Literature Database in May 2017. Studies comparing treatment effects of NPPV with oxygen therapy in stable hypercapnic COPD patients with respiratory failure were conducted, and at least one of the following parameters were reviewed: frequency of acute exacerbation, mortality, lung function, respiratory muscle function, gas exchange, exercise capacity.

RESULTS

Seven studies with 810 subjects were identified. The partial pressure of arterial carbon dioxide (PaCO2) significantly decreased in patients who received long-term NPPV (weighted mean difference [WMD] -3.73, 95% CI: -5.83 to -1.64, P=0.0005). No significant difference was found in mortality, partial pressure of arterial oxygen (PaO2), frequency of acute exacerbation, lung function, respiratory muscle function and exercise capacity. The subgroup analysis showed that NPPV significantly improved the survival of patients when it was targeted at greatly reducing hypercapnia (WMD 0.35, 95% CI: 0.19 to 0.64, P=0.0006).

CONCLUSION

The results indicate that long-term NPPV decreases the PaCO2 of stable hypercapnic COPD patients with respiratory failure and improves mortality with the aim of reducing PaCO2.

Bronchoscopic intubation during continuous nasal positive pressure ventilation in the treatment of hypoxemic respiratory failure

Endotracheal intubation is difficult in patients with hypoxemic respiratory failure who deteriorate despite treatment with noninvasive positive pressure ventilation (NIPPV). Maintaining NIPPV during intubation may prevent alveolar derecruitment and deterioration in gas exchange. We report a case series of 10 nonconsecutive patients with NIPPV failure who were intubated via a flexible bronchoscope during nasal mask positive pressure ventilation. All 10 patients were intubated in the first attempt. Hypotension was the most frequent complication (33%). Mean decrease in oxyhemoglobin saturation during the procedure was 4.7 ± 3.1. This method of intubation may extend the benefits of preoxygenation throughout the whole process of endotracheal intubation. It requires an experienced operator and partially cooperative patients. A prospective trial is necessary to determine the best intubation method for NIPPV failure.

Titration and follow-up for home noninvasive positive pressure ventilation in chronic obstructive pulmonary disease: The potential role of tele-monitoring and the Internet of things

INTRODUCTION

Home noninvasive positive pressure ventilation (NIPPV) has become a well-established treatment for stable hypercapnic chronic obstructive pulmonary disease (COPD) patients. There are still other challenges including appropriate titration of ventilator parameters, adequacy of follow-up, monitoring, and management at home to ensure effectiveness and security, and to improve quality of life. The Internet of Things (IoT) is the name given to the network of devices and other "things" with built-in sensors, software, electronics, and network connectivity, which can communicate these objects over wireless networks and then send data to a cloud platform. Reliable tele-monitoring and transmission of clinical parameters from home to hospitals have prompted the development of IoT-based home NIPPV.

OBJECTIVES

This review provides an overview of titration and follow-up of home NIPPV and focuses on different technologies, modalities, managements, and cost-effectiveness used in IoT-based tele-monitoring of home mechanical ventilation.

DATA SOURCE

Literature search of Web of Science, PubMed, and EMBASE was made to find relevant articles about tele-monitoring and the IoT in home mechanical ventilation over the last 15 years. We used the following search terms: NIPPV, COPD, home mechanical ventilation, telemedicine, tele-monitoring, and management.

CONCLUSION

IoT-based management of home NIPPV, such as home titration and follow-up with the use of tele-monitoring, are emerging and yielding positive findings. However, clear conclusions based on RCT of tele-monitoring in COPD patients with NIPPV at home are only a few and large-scale multicenter studies are required for replication and further validation.

Clinical impact of episodic nocturnal hypercapnia and its treatment with noninvasive positive pressure ventilation in patients with stable advanced COPD

Purpose

Episodic nocturnal hypercapnia (eNH) caused by rapid eye movement (REM) sleep-related hypoventilation is often noted in patients with advanced COPD. The purpose of this study was to clarify the clinical significance of eNH and the effectiveness of eNH-targeted noninvasive positive pressure ventilation (NPPV).

Patients and methods

We enrolled patients with stable, severe, or very severe COPD with daytime arterial partial oxygen pressure PaO₂ ≥55 mmHg and daytime arterial partial carbon dioxide pressure PaCO₂ <55 mmHg, who underwent overnight transcutaneous carbon dioxide pressure (PtcCO₂) monitoring from April 2013 to April 2016. We retrospectively compared clinical characteristics, daytime blood gas analysis, frequency of exacerbation, serum albumin levels, and ratio of pulmonary artery to aorta diameter (PA:A ratio), between patients with COPD with and without eNH. For those with eNH, we applied NPPV and compared these clinical characteristics before and after NPPV.

Results

Twenty-one patients were finally included in this study. Ten patients (47.6%) were evaluated to have eNH. These patients had lower albumin levels (p=0.027), larger PA:A ratio (p=0.019), and higher frequency of exacerbations during the last year (p=0.036). NPPV for the patients with eNH improved daytime PaCO₂ compared with that 12 months after NPPV (p=0.011). The frequency of exacerbations 1 year before NPPV decreased 1 year after NPPV (p=0.030). Serum albumin levels improved 1 year after NPPV (p=0.001).

Conclusion

In patients with stable severe or very severe COPD, eNH may be a risk factor of exacerbations, hypoalbuminemia, and pulmonary hypertension. NPPV may be effective against hypoalbuminemia and acute exacerbations. However, further study is necessary to validate these findings.

Cost-effectiveness of noninvasive ventilation for chronic obstructive pulmonary disease-related respiratory failure in Indian hospitals without ICU facilities

Introduction:

The majority of Indian hospitals do not provide intensive care unit (ICU) care or ward-based noninvasive positive pressure ventilation (NIV). Because no mechanical ventilation or NIV is available in these hospitals, the majority of patients suffering from respiratory failure die.

Objective:

To perform a cost-effective analysis of two strategies (ward-based NIV with concurrent standard treatment vs standard treatment alone) in chronic obstructive pulmonary disease (COPD) respiratory failure patients treated in Indian hospitals without ICU care.

Materials and Methods:

A decision-analytical model was created to compare the cost-effectiveness for the two strategies. Estimates from the literature were used for parameters in the model. Future costs were discounted at 3%. All costs were reported in USD (2012). One-way, two-way, and probabilistic sensitivity analysis were performed. The time horizon was lifetime and perspective was societal.

Results:

The NIV strategy resulted in 17.7% more survival and was slightly more costly (increased cost of $101 (USD 2012) but resulted in increased quality-adjusted life-years (QALYs) (1.67 QALY). The cost-effectiveness (2012 USD)/QALY in the standard and NIV groups was $78/QALY ($535.02/6.82) and $75/QALY ($636.33/8.49), respectively. Incremental cost-effectiveness ratio (ICER) was only $61 USD/QALY. This was substantially lower than the gross domestic product (GDP) per capita for India (1489 USD), suggesting the NIV strategy was very cost effective. Using a 5% discount rate resulted in only minimally different results. Probabilistic analysis suggests that NIV strategy was preferred 100% of the time when willingness to pay was >$250 2012 USD.

Conclusion:

Ward-based NIV treatment is cost-effective in India, and may increase survival of patients with COPD respiratory failure when ICU is not available.

Republication: All India Difficult Airway Association 2016 Guidelines for Tracheal Intubation in the Intensive Care Unit

Tracheal intubation (TI) is a routine procedure in the Intensive Care Unit (ICU) and is often lifesaving. In contrast to the controlled conditions in the operating room, critically ill patients with respiratory failure and shock are physiologically unstable. These factors, along with under evaluation of the airway and suboptimal response to preoxygenation, are responsible for a high incidence of life-threatening complications such as severe hypoxemia and cardiovascular collapse during TI in the ICU. The All India Difficult Airway Association (AIDAA) proposes a stepwise plan for safe management of the airway in critically ill patients. These guidelines have been developed based on available evidence; Wherever, robust evidence was lacking, recommendations were arrived at by consensus opinion of airway experts, incorporating the responses to a questionnaire sent to members of the (AIDAA) and Indian Society of Anaesthesiologists. Noninvasive positive pressure ventilation for preoxygenation provides adequate oxygen stores during TI for patients with respiratory pathology. Nasal insufflation of oxygen at 15 L/min can increase the duration of apnea before hypoxemia sets in. High flow nasal cannula oxygenation at 60-70 L/min may also increase safety during intubation of critically ill patients. Stable hemodynamics and gas exchange must be maintained during rapid sequence induction. It is necessary to implement an intubation protocol during routine airway management in the ICU. Adherence to a plan for difficult airway management incorporating the use of intubation aids and airway rescue devices and strategies is useful.

Noninvasive positive pressure ventilation in unplanned extubation

BACKGROUND:

Unplanned extubation is quite common in intensive care unit (ICU) patients receiving mechanical ventilatory support. The present study aimed to investigate the effectiveness of noninvasive positive pressure ventilation (NPPV) in patients with unplanned extubation.

MATERIALS AND METHODS:

A total of 15 patients (12 male, age: 57 ± 24 years, APACHE II score: 19 ± 7) monitored at the medical ICU during the year 2004 who developed unplanned extubation were included in the study. NPPV was tried in all of them following unplanned extubation. Indications for admission to the ICU were as follows: nine patients with pneumonia, three with status epilepticus, one with gastrointestinal bleeding, one with cardiogenic pulmonary edema and one with diffuse alveolar bleeding.

RESULTS:

Eleven of the patients (74%) were at the weaning period at the time of unplanned extubation. Among these 11 patients, NPPV was successful in 10 (91%) and only one (9%) was reintubated due to the failure of NPPV. The remaining four patients (26%) had pneumonia and none of them were at the weaning period at the time of extubation, but their requirement for mechanical ventilation was gradually decreasing. Unfortunately, an NPPV attempt for 6–8 h failed and these patients were reintubated.

CONCLUSIONS:

Patients with unplanned extubation before the weaning criteria are met should be intubated immediately. On the other hand, when extubation develops during the weaning period, NPPV may be an alternative. The present study was conducted with a small number of patients, and larger studies on the effectiveness of NPPV in unplanned extubation are warranted for firm conclusions.

Noninvasive positive pressure ventilation for acute respiratory failure following oesophagectomy: Is it safe? A systematic review of the literature

OBJECTIVE

To find, critically appraise and synthesise all published studies so as to determine the safety and spectrum of use of noninvasive positive pressure ventilation for acute respiratory failure following oesophagectomy.

DESIGN

Systematic review.

METHODS

The MEDLINE and EMBASE databases were searched and the quality of the studies and any bias or confounding were rated according to established protocols. Outcomes extracted included re-intubation, anastomotic leakage, length of intensive care unit stay and mortality. The data were analysed quantitatively and qualitatively. Pooling of outcomes was considered if appropriate.

RESULTS

The search identified four papers, demonstrating the understudying/underreporting of the topic. Three were case-series and one was a conference abstract. The overall methodological quality was low. Design-specific biases and confounding were high. Despite this, the included studies conclude that noninvasive positive pressure ventilation is safe and effective and that re-intubation rates, intensive care unit length of stay, mortality and anastomotic dehiscence is lower when it is used. Meta-analysis was deemed to be inappropriate.

CONCLUSIONS

Despite the conclusions and consensus of the included studies, there is no evidence to definitively conclude that noninvasive positive pressure ventilation is either safe or dangerous following oesophagectomy and the current literary evidence is inadequate. Current practice varies and is based on opinion and consensus. As such, randomised controlled studies are urgently required as current practice may cause undue harm to patients. The incidence of anastomotic leakage with noninvasive positive pressure ventilation use needs to be determined.

Pulmonary Drug Delivery Following Continuous Vibrating Mesh Nebulization and Inspiratory Synchronized Vibrating Mesh Nebulization During Noninvasive Ventilation in Healthy Volunteers

BACKGROUND

A breath-synchronized nebulization option that could potentially improve drug delivery during noninvasive positive pressure ventilation (NIPPV) is currently not available on single-limb circuit bilevel ventilators. The aim of this study was to compare urinary excretion of amikacin following aerosol delivery with a vibrating mesh nebulizer coupled to a single-limb circuit bilevel ventilator, using conventional continuous (Conti-Neb) and experimental inspiratory synchronized (Inspi-Neb) nebulization modes.

MATERIALS AND METHODS

A crossover clinical trial involving 6 noninvasive ventilated healthy volunteers (mean age of 32.3 ± 9.5 y) randomly assigned to both vibrating mesh nebulization modes was conducted: Inspi-Neb delivered aerosol during only the whole inspiratory phase, whereas Conti-Neb delivered aerosol continuously. All subjects inhaled amikacin solution (500 mg/4 mL) during NIPPV using a single-limb bilevel ventilator (inspiratory positive airway pressure: 12 cm H₂O, and expiratory positive airway pressure: 5 cm H₂O). Pulmonary drug delivery of amikacin following both nebulization modes was compared by urinary excretion of drug for 24 hours post-inhalation.

RESULTS

The total daily amount of amikacin excreted in the urine was significantly higher with Inspi-Neb (median: 44.72 mg; interquartile range [IQR]: 40.50-65.13) than with Conti-Neb (median: 40.07 mg; IQR: 31.00-43.73), (p = 0.02). The elimination rate constant of amikacin (indirect measure of the depth of drug penetration into the lungs) was significantly higher with Inspi-Neb (median: 0.137; IQR: 0.113-0.146) than with Conti-Neb (median: 0.116; IQR: 0.105-0.130), (p = 0.02). However, the mean pulmonary drug delivery rate, expressed as the ratio between total daily urinary amount of amikacin and nebulization time, was significantly higher with Conti-Neb (2.03 mg/min) than with Inspi-Neb (1.09 mg/min) (p < 0.01).

CONCLUSIONS

During NIPPV with a single-limb circuit bilevel ventilator, the use of inspiratory synchronized vibrating mesh nebulization may improve pulmonary drug delivery compared with conventional continuous vibrating mesh nebulization.

Noninvasive positive pressure ventilation is required following extubation at the pulmonary infection control window: a prospective observational study

INTRODUCTION

Timely extubation and sequential invasive to noninvasive positive pressure ventilation (NPPV) at the pulmonary infection control (PIC) window is beneficial for patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). However, it remains unclear whether patients can breathe independently at the PIC window and if NPPV is indeed necessary after extubation.

OBJECTIVES

To assess whether AECOPD patients can breathe independently at the PIC window and thus whether NPPV is necessary after extubation.

METHODS

We performed a prospective observational study at a university hospital during a 9-month period. We used the spontaneous breathing trial (SBT) to assess whether each patient could breathe independently at the PIC window, then performed extubation. Patients who passed the SBT received venturi oxygen therapy only, whereas those that failed received NPPV. However, if the former showed respiratory distress, they too received NPPV. The primary outcome variables were SBT pass/fail, the demand for NPPV and rate of reintubation within 72 h following extubation.

RESULTS

In all, 23 patients were enrolled, 15 (65%) of which passed the SBT. Of these, 12 (80%) developed respiratory distress after extubation and required NPPV (one of whom required reintubation). Of the eight patients that failed, one received reintubation after NPPV. The reintubation rates within 72 h following extubation of SBT-pass (7%) and SBT-fail (13%) patients were comparable.

CONCLUSION

Our results provide experimental evidence that most AECOPD patients can breathe independently at the PIC window, but nonetheless develop respiratory distress and thus require NPPV following extubation.

Outcomes of unplanned extubation in ordinary ward are similar to those in intensive care unit: A STROBE-compliant case-control study

Unplanned extubation (UE) may cause considerable adverse effects in patients receiving mechanical ventilation (MV). Previous literature showed inconsistent prognosis in patients with UE. This study aimed to evaluate the clinical implications and outcomes of UE.The intubated adult patients with MV support in our hospital were enrolled, and they were divided into the UE and non-UE groups. Demographic data, admission unit, MV duration, overall weaning rate, and mortality rates were compared. The outcomes of UE in ordinary ward and intensive care unit (ICU) were also assessed.Totally 9245 intubated adult patients were included. UE occurred in 303 (3.5%) patients, and the UE events were 0.27 times/100 MV days. Old age, nonoperation related MV cause, and admission out of the ICU were significant factors associated with UE events. UE patients showed a trend of better overall weaning rate (71.9% vs 66.7%, P = .054) than non-UE. However, the in-hospital mortality rate (25.7% vs 24.8%, P = .713) were similar between the UE and non-UE patients. The reintubation rate of UE patients was 44.1% (142/322). Successful UEs were associated with patients in weaning process (52.8% vs 38.7%, P = .012), and patients received non-invasive positive pressure ventilation (NIPPV) support after UE (19.4% vs 3.5%, P < .001). Patients with successful UE had significantly shorter MV days, higher overall weaning rate, and lower mortality than those with unsuccessful UE. Outcomes of UE in ordinary ward and in ICU had similar MV duration, reintubation rate, overall weaning rate, and in-hospital mortality rate.The overall weaning rate and in-hospital mortality rates of the UE and non-UE patients were similar. UE occurred in ordinary ward had similar outcomes to those in ICU. Patients receiving MV should be assessed daily for weaning indications to reduce delayed extubation, and therefore, may decrease UE occurrence. Once the UE happened, NIPPV support may reduce the reintubation rate.

Prophylactic use of noninvasive positive pressure ventilation in post-thoracic surgery patients: A prospective randomized control study

OBJECTIVE

Prospective randomized controlled study was conducted to explore the effects and safety of prophylactic use of noninvasive positive pressure ventilation (NPPV) in post-thoracic surgery (PTS) patients, especially on the lung re-expansion, lung function change and postoperative pulmonary complications (PPCs).

METHODS

Fifty PTS patients met the inclusion criterion were enrolled in the study. All subjects were randomly divided into conventional treatment (control) group and NPPV group. NPPV group received intermittent NPPV therapy in first three days of PTS. BiPAP ventilator was used with S/T mode in the study. The average IPAP was (13±3.2)cmH(2)O (ranged from 7 to 18 cmH(2)O) and EPAP was 4cmH(2)O. Total ventilation time was (13.5±4.9) hours (ranged from 6.5 to 23 hours). PPCs rate, lung re-expansion, the volume of residual cavity, lung function and tolerance to NPPV were assessed with chest roentgenography, CT scan, lung function testing and clinical evaluation before and one week after surgery.

RESULTS

1. There was no significant difference of total PPCs rate during hospitalization between the two groups (5/23 in NPPV group vs 6/27 in control group, P= 0.967). Multiple factorial logistic regression analysis showed that COPD was a risk factor for PPCs (B=1.705, P=0.027). 2. Compared with control group, NPPV therapy reduced inadequate lung expansion rate (3/23 vs 13/27, P=0.008) and volume of residual cavity calculated with CT scan [(31.9±71.7)ml vs (63.6±78.3)ml, P=0.02]. However, there were no significant difference in the change of lung function parameters after operation between the two groups (all P>0.05). No significant adverse effects of NPPV were found in the present study.

CONCLUSIONS

In the current study of prophylactic application of NPPV in post-thoracic surgery patients, the use of NPPV resulted in improved lung re-expansion, but had no significant effects on post-operative pulmonary complications and lung functions.

Management of immune checkpoint inhibitor-related acute hypoxic neuromuscular respiratory failure using high-flow nasal cannula

Immune-related adverse events are increasingly associated with the use of immune checkpoint inhibitors for treatment of cancers. While neurological immune-related adverse events are rare, immune-related myasthenia gravis and immune-related myositis can lead to myasthenic crisis and acute respiratory failure. High-flow nasal cannula is an emerging alternative in critically ill patients for early treatment in neuromuscular acute hypoxic respiratory failure as well as for those who cannot endure noninvasive positive pressure ventilation with face mask. We describe use of high-flow nasal cannula in a patient with acute hypoxic respiratory failure and psychological distress due to the immune-related adverse event of myasthenic crisis.

Low-intensity noninvasive ventilation: Lower pressure, more exacerbations of chronic respiratory failure

BACKGROUND:

For patients with chronic respiratory failure (CRF) who are treated with noninvasive positive pressure ventilation (NPPV), a little is known regarding the effects of low-intensity NPPV (LI-NPPV) on the clinical course of CRF and the frequency of adjustments in these patients.

OBJECTIVES:

This study investigated the effects of LI-NPPV on the clinical course of patients with CRF as compared with patients who were treated with conventional NPPV (C-NPPV) and determined how frequently NPPV was adjusted during therapy.

METHODS:

Clinical data from 21 patients who received long-term NPPV were retrospectively analyzed. Patients were categorized into two groups based on the level of initial pressure support (PS): C-NPPV group (PS ≥ 10 cm H₂O) and LI-NPPV group (PS < 10 cm H₂O).

RESULTS:

Patients in the LI-NPPV group had significantly more exacerbations of CRF (P < 0.05). There was no significant difference in the number of patients who required adjustments of NPPV settings between the two groups. There was no significant difference in PaCO₂ levels 1 month after the start of NPPV between the two groups; however, PaCO₂ levels were significantly lower after 1 year in the C-group (P < 0.001). Seventy-one percent of LI-NPPV patients and 43% of C-NPPV patients needed NPPV adjustments.

CONCLUSIONS:

Attention should be paid to CRF patients who are initially administered LI-NPPV; they should be carefully observed because they can develop more exacerbations of CRF than patients undergoing C-NPPV. If possible, higher initial PS should be administered to prevent CRF exacerbations.

Vibration response imaging: a novel noninvasive tool for evaluating the initial therapeutic effect of noninvasive positive pressure ventilation in patients with acute exacerbation of chronic obstructive pulmonary disease

BACKGROUND

The popular methods for evaluating the initial therapeutic effect (ITE) of noninvasive positive pressure ventilation (NPPV) can only roughly reflect the therapeutic outcome of a patient's ventilation because they are subjective, invasive and time-delayed. In contrast, vibration response imaging (VRI) can monitor the function of a patient's ventilation over the NPPV therapy in a non-invasive manner. This study aimed to investigate the value of VRI in evaluating the ITE of NPPV for patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

METHODS

Thirty-six AECOPD patients received VRI at three time points: before NPPV treatment (T1), at 15 min of NPPV treatment (T2), and at 15 min after the end of NPPV treatment (T4). Blood gas analysis was also performed at T1 and at 2 hours of NPPV treatment (T3). Thirty-nine healthy volunteers also received VRI at T1 and T2. VRI examination at the time point T2 in either the patients or volunteers did not require any interruption of the on-going NPPV. The clinical indices at each time point were compared between the two groups. Moreover, correlations between the PaCO2 changes (T3 vs T1) and abnormal VRI scores (AVRIS) changes (T2 vs T1) were analyzed.

RESULTS

No significant AVRIS differences were found between T1 and T2 in the healthy controls (8.51 ± 3.36 vs. 8.53 ± 3.57, P > 0.05). The AVRIS, dynamic score, MEF score and EVP score showed a significant decrease in AECOPD patients at T2 compared with T1 (P < 0.05), but a significant increase at T4 compared with T2 (P < 0.05). We also found a positive correlation (R2 = 0.6399) between the PaCO2 changes (T3 vs T1) and AVRIS changes (T2 vs T1).

CONCLUSIONS

VRI is a promising noninvasive tool for evaluating the initial therapeutic effects of NPPV in AECOPD patients and predicting the success of NPPV in the early stage.

Gastric Emphysema and Hepatic Portal Vein Gas as Complications of Noninvasive Positive Pressure Ventilation

Gastric emphysema (GE) in association with hepatic portal vein gas (HPVG) is a rare, benign medical condition that is very seldom caused by noninvasive positive pressure ventilation (NIPPV). This report describes a patient who developed GE along with gastric vein gas and HPVG, most likely due to multiple episodes of vomiting in combination of using bilevel positive airway pressure (BiPAP), a form of NIPPV. The patient responded to conservative treatment with intravenous fluids, pantoprazole, and the urgent cessation of BiPAP and oral intake.

Autocycling During Noninvasive Positive Pressure Ventilation Producing a Prolonged Severe Apnea and Syncope

ABSTRACT

Autocycling is a form of patient-ventilator asynchrony that can occur during mechanical ventilation. In the case described, autocycling during noninvasive ventilation led to severe hyperventilation and subsequently produced a prolonged central apnea that resulted in syncope. This case represents the first description of a severe adverse event from autocycling during noninvasive ventilation.

Noninvasive positive pressure ventilation for treating acute asthmatic attacks in three pregnant women with dyspnea and hypoxemia

In our case reports, we mentioned about the utility of NPPV therapy in addition to standard pharmacologic therapy for acute asthma exacerbations in pregnant women with dyspnea and hypoxemia compared with that of oxygen therapy alone. Careful patient selection and clinicians' NPPV experience are crucial in optimizing patient outcomes.