Noninvasive Pressure Support Ventilation Research Articles

Accuracy of the estimations of respiratory mechanics using an expiratory time constant in passive and active breathing conditions: a bench study

BackgroundRespiratory mechanics monitoring provides useful information for guiding mechanical ventilation, but many measuring methods are inappropriate for awake patients. This study aimed to evaluate the accuracy of dynamic mechanics estimation using expiratory time constant (RCexp) calculation during noninvasive pressure support ventilation (PSV) with air leak in different lung models.MethodsA Respironics V60 ventilator was connected to an active breathing simulator for modeling five profiles: normal adult, restrictive, mildly and severely obstructive, and mixed obstructive/restrictive. Inspiratory pressure support was adjusted to maintain tidal volumes (VT), achieving 5.0, 7.0, and 10.0 ml/kg body weight. PEEP was set at 5 cmH2O, and the back-up rate was 10 bpm. Measurements were conducted at system leaks of 25–28 L/min. RCexp was estimated from the ratio at 75% exhaled VT and flow rate, which was then used to determine respiratory system compliance (Crs) and airway resistance (Raw).ResultsIn non-obstructive conditions (Raw ≤ 10 cmH2O/L/s), the Crs was overestimated in the PSV mode. Peak inspiratory and expiratory flow and VT increased with PS levels, as calculated Crs decreased. In passive breathing, the difference of Crs between different VT was no significant. Underestimations of inspiratory resistance and expiratory resistance were observed at VT of 5.0 ml/kg. The difference was minimal at VT of 7.0 ml/kg. During non-invasive PSV, the estimation of airway resistance with the RCexp method was accurately at VT of 7.0 ml/kg.ConclusionsThe difference between the calculated Crs and the preset value was influenced by the volume, status and inspiratory effort in spontaneously breathing.

Modeling the therapy system of noninvasive pressure support ventilation with the respiratory patient in COPD and ARDS

The noninvasive pressure support ventilation (NPSV) has been one of mechanical ventilation widely applied for the respiratory patients in chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS), etc. To investigate and develop the technologies in NPSV conveniently and in low-cost, in this article, a therapy system model of NPSV was designed with developing the mathematical submodels of NPSV respirator and respiratory patient in COPD and ARDS. By simulating the respirator, breath circuit, mask and respiratory patients, a MATLAB-based virtual experimental platform was developed for virtual ventilations. And in order to test the authenticity and practicability of the therapy system model of NPSV, a lot of ASL5000-based physical experiments were carried out for comparative analysis with the simulated outputs: pressures, flows and volumes. The statistical conclusions demonstrate that the simulated results are consist with the results from the physical experiments (TTEST P > 0.39). The experimental results tell that the therapy system model of NPSV is effective and workable. The developed therapy system model of NPSV will be beneficial for clinician and researcher to explore the therapeutic methods and some potential measures in NPSV for saving the respiratory patient’s health and life.

Pneumomediastinum is a poor prognostic factor in COVID-19 patients – case series and review

During the second wave of COVID-19, a number of patients requiring invasive or noninvasive pressure support ventilation rose significantly. The cases of pneumomediastinum (PM), pneumothorax (PTX), and subcutaneous emphysema (SCE) were also reported, largely attributed to barotrauma with observation of some spontaneous cases. Here, we present seven moderate-to-severe COVID-19 cases with variable severity developing PM with or without PTX and SCE during the course of hospitalization. Five received noninvasive ventilation, of whom two required invasive mechanical ventilation. The remaining two patients received oxygen therapy alone. Two patients required insertion of intercostal chest drainage tubes for pneumothoraces. Appropriate medical management was given to all patients. Three patients improved and were discharged from the hospital, while four expired. The case series highlights need of early diagnosis, constant monitoring, and judicious use of pressure support ventilation to prevent air leak complications in COVID-19 patients in order to improve their prognostic outcomes.

Systematic review and meta-analysis on perioperative intervention to prevent postoperative atelectasis complications after thoracic surgery.

In clinical general thoracic surgery, the prevalence of atelectasis is relatively high. Perioperative interventions can affect the probability of patients with atelectasis after surgery. Therefore, the incidence of perioperative intervention to prevent atelectasis after thoracic surgery was discussed using meta-analysis in this study. The articles were searched in the English database PubMed and Chinese databases including China National Knowledge Infrastructure (CNKI), VIP, and China Journal Full-text Database (CJFD). The duration for publication time of the articles was from the database inception to March 2021, and the articles were required to be randomized controlled trials (RCTs) using interventions [such as changing the dose of general anesthesia, continuous positive end expiratory pressure (PEEP), non-invasive pressure support ventilation, and physical therapy] after thoracic surgery (such as pulmonary lobectomy, sternum surgery, and lung cancer surgery) for the treatment of atelectasis. The software RevMan 5.3 provided by the Cochrane Collaboration was used for meta-analysis. A total of 5 articles were obtained, including 375 cases in the control group and 268 cases in the intervention treatment group. A meta-analysis was performed on the included articles, combined effect model analysis results showed that compared with the control group, the use of PEEP during mechanical ventilation can significantly reduce the incidence of atelectasis [odds ratio (OR) =0.46; 95% confidence interval (CI): 0.31-0.67; Z=3.94; P<0.0001]. Perioperative intervention was more effective for postoperative atelectasis and other complications.

Non invasive ventilation and right ventricle function in cardiogenic pulmonary edema: an echocardiographic perspective to select the "right" ventilatory support

Abstract Funding Acknowledgements Type of funding sources: None. Background High-flow nasal cannulae oxygen therapy (HFNCOT) represents a better tolerated alternative to non-invasive pressure support ventilation (NIPSV) for acute cardiogenic pulmonary edema (ACPE) treatment. However, there are still few data on the effect of HFNCOT on cardiac function and hemodynamic. Purpose To assess and compare the effects of NIPSV and HFNCOT in ACPE setting on right ventricular (RV) systolic function and on indices of cardiac filling and output, as measured by echocardiography. Methods This is a cross-over controlled study, enrolling 15 consecutive patients admitted to our Cardiovascular Intensive Care Unit for ACPE and hypoxaemic, normo/hypocapnic acute respiratory failure, with P/F ratio &amp;lt; 200. Each patient received NIPSV, followed by HFNCOT. Full echocardiographic assessment and blood gas analysis (BGA) were performed 40 minutes from onset of each ventilation modality, respectively before NIPSV to HFNCOT switch and before HFNCOT interruption. In particular, RV function parameters, together with RV and atrial strain, were prospectively collected. Results In spite of not significant changes in BGA, RV function was significantly improved under HFNCOT, as compared to NIPSV, as assessed by the following parameters: tricuspid annular plane excursion (TAPSE) (P = 0.001), RV S’ wave (P = 0.007), RV fractional area change (RVFAC) (P = 0.006). Strain analysis confirmed the significant improvement in RV function, with free wall global longitudinal strain (GLS) and free wall and septum GLS significantly higher under HFNCOT, as compared to NIPSV (-21% vs -18% P &amp;lt; 0.001, and -15% vs -19% P = 0.008, respectively,), and a significant increase in right atrial positive longitudinal strain (P &amp;lt; 0.001). Conclusions NIPSV significantly affect RV function making more complex the management of patients presenting with ACPE. In this setting, HFNCOT represents a valuable alternative, providing similar respiratory outcomes while preserving good right ventricle performance.

Accuracy of the dynamic signal analysis approach in respiratory mechanics during noninvasive pressure support ventilation: a bench study.

ObjectiveTo evaluate the accuracy of respiratory mechanics using dynamic signal analysis during noninvasive pressure support ventilation (PSV).MethodsA Respironics V60 ventilator was connected to an active lung simulator to model normal, restrictive, obstructive, and mixed obstructive and restrictive profiles. The PSV was adjusted to maintain tidal volumes (VT) that achieved 5.0, 7.0, and 10.0 mL/kg body weight, and the positive end-expiration pressure (PEEP) was set to 5 cmH2O. Ventilator performance was evaluated by measuring the flow, airway pressure, and volume. The system compliance (Crs) and airway resistance (inspiratory and expiratory resistance, Rinsp and Rexp, respectively) were calculated.ResultsUnder active breathing conditions, the Crs was overestimated in the normal and restrictive models, and it decreased with an increasing pressure support (PS) level. The Rinsp calculated error was approximately 10% at 10.0 mL/kg of VT, and similar results were obtained for the calculated Rexp at 7.0 mL/kg of VT.ConclusionUsing dynamic signal analysis, appropriate tidal volume was beneficial for Rrs, especially for estimating Rexp during assisted ventilation. The Crs measurement was also relatively accurate in obstructive conditions.

Average volume-assured pressure support vs conventional bilevel pressure support in pediatric nocturnal hypoventilation: a case series.

Average volume-assured pressure support (AVAPS) is a modality of noninvasive ventilation that provides a targeted tidal volume by automatically adjusting the inspiratory pressure support within a set range. Pediatric studies evaluating the efficacy of AVAPS in treating nocturnal hypoventilation are confined to case reports. The aim of this study was to compare AVAPS to conventional bilevel positive airway pressure (BPAP) support in improving hypercarbia in a cohort of pediatric patients with nocturnal hypoventilation. Retrospective review of patient records at an established tertiary pediatric sleep laboratory over a 6-year period. Ventilatory and sleep study parameters from AVAPS and conventional BPAP titration studies were compared. AVAPS was used only if hypoventilation was not controlled using conventional BPAP. Inspiratory pressures, tidal volumes, and adherence were downloaded on final titrated ventilatory settings. Comparisons were made using paired t test. A total of 19 patients (11 boys, 8 girls; median age 10.5 years, range 1 to 20 years) were identified. Diagnoses included neuromuscular disease (n = 9), obstructive hypoventilation (n = 5), parenchymal lung disease (n = 4), and congenital central hypoventilation syndrome (n = 2). AVAPS demonstrated significant improvement in peak (P = .009) and mean (P = .001). Transcutaneous CO₂ parameters compared to conventional bilevel. Oxygenation on AVAPS showed positive trend but did not reach statistical significance. AVAPS delivered higher tidal volumes (P = .04) using similar pressures. There was no statistically significant difference in obstructive apnea-hypopnea index, respiratory arousal index, sleep efficiency, and adherence between AVAPS and conventional BPAP. AVAPS was an effective alternative to conventional BPAP in improving hypercarbia in our selective cohort of pediatric patients. Prospective, longitudinal studies are needed to evaluate the benefits of AVAPS feature in the pediatric population.

Noninvasive Neurally Adjusted Ventilator Assist Ventilation in the Postoperative Period Produces Better Patient-Ventilator Synchrony but Not Comfort.

Background Noninvasive neurally adjusted ventilatory assist (NAVA) has been shown to improve patient-ventilator interaction in many settings. There is still scarce data with regard to postoperative patients indicated for noninvasive ventilation (NIV) which this study elates. The purpose of this trial was to evaluate postoperative patients for synchrony and comfort in noninvasive pressure support ventilation (NIV-PSV) vs. NIV-NAVA. Methods Twenty-two subjects received either NIV-NAVA or NIV-PSV in an object-blind, prospective, randomized, crossover fashion (observational trial). We evaluated blood gases and ventilator tracings throughout as well as comfort of ventilation at the end of each ventilation phase. Results There was an effective reduction in ventilator delays (p < 0.001) and negative pressure duration in NIV-NAVA as compared to NIV-PSV (p < 0.001). Although we used optimized settings in NIV-PSV, explaining the overall low incidence of asynchrony, NIV-NAVA led to reductions in the NeuroSync-index (p < 0.001) and all types of asynchrony except for double triggering that was significantly more frequent in NIV-NAVA vs. NIV-PSV (p = 0.02); ineffective efforts were reduced to zero by use of NIV-NAVA. In our population of previously lung-healthy subjects, we did not find differences in blood gases and patient comfort between the two modes. Conclusion In the postoperative setting, NIV-NAVA is well suitable for use and effective in reducing asynchronies as well as a surrogate for work of breathing. Although increased synchrony was not transferred into an increased comfort, there was an advantage with regard to patient-ventilator interaction. The trial was registered at the German clinical Trials Register (DRKS no.: DRKS00005408).

Recovery from hypoxemia and Hypercapnia following noninvasive pressure support ventilation in a patient with statin-associated necrotizing myopathy: a case report

BackgroundStatin-associated necrotizing myopathy (SANM) is a rare autoimmune disorder caused by administration of statins. SANM is characterized by weakness due to necrosis and regeneration of myofibers. Here we report the first case of SANM with acute respiratory failure treated with noninvasive pressure support ventilation in addition to immunosuppressants.Case presentationA 59-year-old woman who had been treated with 2.5 mg/day of rosuvastatin calcium for 5 years stopped taking the drug 4 months before admission to our hospital due to elevation of creatine kinase (CK). Withdrawal of rosuvastatin for 1 month did not decrease the level of CK, and she was admitted to our hospital due to the development of muscle weakness of her neck and bilateral upper extremities. Anti-3-hydroxy-3-methylglutaryl coenzyme A reductase antibodies were positive. Magnetic resonance imaging showed myositis, and muscle biopsy from the right biceps brachii muscle showed muscle fiber necrosis and regeneration without inflammatory cell infiltration, suggesting SANM. After the diagnosis, she received methylprednisolone pulse therapy (mPSL, 1 g/day × 3 days, twice) and subsequent oral prednisolone therapy (PSL, 30 mg/day for 1 month, 25 mg/day for 1 month and 22.5 mg/day for 1 month), leading to improvement of her muscle weakness. One month after the PSL tapering to 20 mg/day, her muscle weakness deteriorated with oxygen desaturation (SpO2: 93% at room air) due to hypoventilation caused by weakness of respiratory muscles. BIPAP was used for the management of acute respiratory failure in combination with IVIG (20 g/day × 5 days) followed by mPSL pulse therapy (1 g/day × 3 days), oral PSL (30 mg/day × 3 weeks, then tapered to 25 mg/day) and tacrolimus (3 mg/day). Twenty-seven days after the start of BIPAP, she was weaned from BIPAP with improvement of muscle weakness, hypoxemia and hypercapnia. After she achieved remission with improvement of muscle weakness and reduction of serum CK level to a normal level, the dose of oral prednisolone was gradually tapered to 12.5 mg/day without relapse for 3 months.ConclusionsOur report provides new insights into the role of immunosuppressants and biphasic positive airway pressure for induction of remission in patients with SANM.

Effects of volume-assured pressure support noninvasive ventilation in stable COPD with chronic respiratory failure: Meta-analysis and literature review

BackgroundPatients receiving long-term home noninvasive ventilation (NIV) may slow down the progression to acute exacerbation of chronic obstructive pulmonary disease (AECOPD), however, the problem with respiratory instability during sleep diminished was persisted, which may reduce the effectiveness of NIV and the patient's quality of life. A novel NIV mode with volume-assured pressure support (VAPS) has been gradually applied to improve sleep quality in COPD patients with chronic respiratory failure. This meta-analysis aimed to evaluate the efficacy of VAPS in stable COPD patients with chronic respiratory failure. MethodsWe performed an electronic literature search for RCTs from January 2008 to October 2018. Studies investigating the effects of VAPS in stable COPD patients with chronic respiratory failure were conducted, and the following primary outcomes were reviewed: effectiveness of ventilation, sleep quality, and quality of life. ResultsFive studies with 150 subjects were identified. While questionnaire scores showed significant improvements in the VAPS mode, no significant difference was found in the effectiveness of ventilation (pH, MD = 0.01 [95% CI -0.01 to 0.02, P = 0.27]; PaCO2, MD = 1.25 [95% CI -1.45 to 3.95, P = 0.37]; PaO2, MD = 3.14 [95% CI -0.76 to 7.05, P = 0.11]; mSaO2, MD = 0.23 [95% CI -1.22 to 1.67, P = 0.76]; mPtcCO2, MD = 3.03 [95% CI -6.06 to- 0.60, P = 0.10]). The VAPS mode did not seem to ameliorate sleep quality and quality of life. ConclusionThe VAPS mode had similar efficacy as the pressure-support (PS) mode. However, VAPS could significantly improve the patients’ subjective feelings.

Tidal Volume Estimation during Helmet Noninvasive Ventilation: an Experimental Feasibility Study

We performed a bench (BS) and human (HS) study to test the hypothesis that estimation of tidal volume (VT) during noninvasive helmet pressure support ventilation (nHPSV) would be possible using a turbine driven ventilator (TDV) coupled with an intentional leak single-limb vented circuit. During the BS a mannequin was connected to a lung simulator (LS) and at different conditions of respiratory mechanics, positive end expiratory pressure (PEEP) levels and leaks (30, 50 and 80 L/min). All differences were within the 95% limits of agreement (LoA) in all conditions in the Bland-Altman plot. The overall bias (difference between VT measured by TDV and LS) was 35 ml (95% LoA 10 to 57 ml), 15 ml (95% LoA −40 to 70 ml), 141 ml (95% LoA 109 to 173 ml) in the normal, restrictive and obstructive conditions. The bias at different leaks flow in normal condition was 29 ml (95% LoA 19 to 38 ml). In the HS four healthy volunteers using nHPSV had a pneumotachograph (P) inserted through a mouthpiece to measure subject’s VT.The bias showed a scarce clinical relevance. In conclusions, VT estimation seems to be feasible and accurate in all conditions but the obstructive one. Additional leaks seem not to affect VT reliability.

Neurally-Adjusted Ventilatory Assist Versus Noninvasive Pressure Support Ventilation in COPD Exacerbation: The NAVA-NICE Trial.

This study was conducted to compare the effectiveness of noninvasive ventilation (NIV) with pressure support (NIV-PSV) to noninvasive neurally-adjusted ventilatory assist (NIV-NAVA) during COPD exacerbation. In this study, 40 subjects with COPD and acute hypercapnic respiratory failure were randomized to receive either NIV-NAVA (n = 20) or NIV-PSV (n = 20) via a critical care ventilator. Subjects' vital parameters, arterial blood gas values, patient-ventilator asynchrony events, and asynchrony index were noted at specific time intervals in both groups. The duration of NIV, rate of NIV failure, and length hospital stay were also recorded for these 2 modes of NIV. NIV-NAVA significantly reduced the total number (median [interquartile range]) of asynchrony events compared to NIV-PSV: 22 (15-32.5) versus 65 (50.75-104.25), respectively, P = .002. Severe asynchrony defined as asynchrony index > 10% was also significantly lower in NIV-NAVA than in NIV-PSV (P < .001). There was no significant difference between the 2 groups regarding improvement in gas exchange and vital parameters. Rate of failure of NIV (P = .73), duration of the requirement of ventilatory support (P = .40), and hospital length of stay (P = .46) were also comparable between the 2 modes of ventilation. Compared to NIV-PSV, NIV-NAVA was associated with better patient-ventilator synchrony and a reduction in the number of asynchrony events in subjects with an exacerbation of COPD, with similar effects on improvement in gas exchange, duration of NIV, hospital lenght of stay, and rate of NIV failure. (Clinicaltrials.gov registration NCT02912689.).

Noninvasive Ventilation in Acute Heart Failure.

To assess the role of noninvasive ventilation (NIV) in acute heart failure (AHF). NIV rapidly improves the respiratory distress and reduces the need for intubation and even mortality in patients with acute cardiogenic pulmonary edema (ACPE). Therefore, NIV is indicated as first line therapy in ACPE. NIV may also be considered in some cases of cardiogenic shock after stabilization. CPAP is an easier and cheaper technique that is recommended as first-line therapy, particularly in pre-hospital or low-equipped areas. Noninvasive pressure support ventilation is equally effective in these scenarios, and may be preferable in patients with mild fatigue or significant hypercapnia, including those with associated chronic obstructive pulmonary disease (COPD). High flow nasal cannula is an alternative for patients who need prolonged ventilation or those who show poor tolerance to these techniques. NIV should be used as a first-line therapy in all patients with ACPE and should be considered in stable cardiogenic shock and AHF associated to COPD.

Comparing the effects and compliance between volume-assured and pressure support non-invasive ventilation in patients with chronic respiratory failure.

Standard bi-level non-invasive ventilation with fixed-level pressure support (PS) delivery may not maintain ventilation during the changes in pulmonary mechanics that occur throughout day and night, so average volume-assured pressure support (AVAPS) modes that target a preset volume by adjustment of PS may be effective. Our meta-analysis wants to compare AVAPS and pressure support non-invasive ventilation (PS-NIV) regarding arterial blood gases (ABGs), sleep efficiency and compliance. Relevant publications indexed in PubMed, Cochrane Library, Embase, Web of Science, Wanfang Data, China National Knowledge Infrastructure and VIPI were identified. Appropriate articles identified from the reference lists of the above searches were also reviewed. We included randomized controlled trials involved the use of AVAPS and PS-NIV ventilation for chronic respiratory failure. Each included study weighted mean differences, and 95% confidence intervals (CI) were calculated for continuous outcomes. Statistical heterogeneity was assessed using the I2 value≤50% were considered as no statistical heterogeneity and used fixed effects model. Otherwise, a random effects model was used. Eight trials were eligible. No significant difference was observed between AVAPS and PS-NIV groups to compare PaCO2 (OR -0.97, CI-2.54-0.61, P=0.23) and PaO2 (OR -1.81, CI-4.29-0.67, P=0.15) in ABGs. There was no significant difference between the two groups with sleep efficiency (OR -3.31, CI-7.58-0.95, P=0.13) and visual analog scale (OR 0.32, CI-6.97-7.61, P=0.93). The evidence shows there is no significant difference in clinical outcomes when comparing AVAPS and PS-NIV used for chronic respiratory failure patients.

New modalities for non-invasive positive pressure ventilation: A review article.

Efficiency of non-invasive positive pressure ventilation in the treatment of respiratory failure has been shown in many published studies. In this review article, we introduced new modalities of non-invasive ventilation (NIV), clinical settings in which NIV can be used and a practical summary of the latest official guidelines published by the European Respiratory Clinical Practice. Clinical trials and review articles in four databases up to 25 February 2018 about new modalities of non-invasive positive pressure ventilation were reviewed. Commonly used modalities for treatment of respiratory failure include: CPAP (continuous positive airway pressure) and BiPAP (bilevel positive airway pressure) or NIPSV (noninvasive pressure support ventilation). The limitations of the BiPAP method are the trigger and cycle asynchrony, inadequate volume delivery and increased respiratory rate. Newer methods, such as adaptive servo-ventilation, have been developed to treat central and complex sleep apnea and the NAVA (neutrally adjusted ventilatory assist) to improve the trigger and cycle asynchrony. In the proportional assist ventilation, unlike the pressure support ventilation, with increased patient effort (flow) the tidal volume increases and it prevents the increase in the respiratory rate and respiratory distress. High-flow nasal cannula is a non-invasive technique that does not provide respiratory support, but provides a mixture of oxygen to the patient. The use of non-invasive pursed-lip breathing ventilation in chronic obstructive pulmonary disease (COPD) patients reduces dyspnea (decreases respiratory rate) and increases blood oxygen saturation. New modalities of NIV improve patient comfort and patient–ventilator interactions, and are recommended in patients with respiratory failure.

Effects of noninvasive proportional assist vs pressure support ventilation on respiratory work in chronic obstructive pulmonary disease patients with hypercapnia

Objective: To investigate the effect of noninvasive proportional assist ventilation (PAV) on respiratory work in chronic obstructive pulmonary disease(COPD) patients, in comparison to noninvasive pressure support ventilation(PSV). Methods: Ten severe COPD patients with hypercapnia during acute exacerbation were examined. The baseline inspiratory pressure of PSV (PS) and the assistance level of PAV(PA) were titrated by patients' tolerance. In addition to the baseline PS and PA, an additional decrease by 25% (PS-=75% PS, PA-=75% PA) or increase by 25% (PS+ =125% PS, PA+ =125% PA) of the assist level were applied to the patients. After the assessment of unassisted spontaneous breathing (SB), the patient was placed on the 6 levels of noninvasive-PSV and noninvasive-PAV in random sequence. Each level lasted at least 20 minutes. Respiratory rate (RR), tidal volume (Vt), and respiratory work(Wex, Wip and Wv) were measured. Asynchrony index (AI) was calculated. Results: During ventilation, Vt was significantly higher with each assist level than with SB. The Vt was significant increased with PS+ than with PA+ . An increase in expiratory work(Wex) and decrease in inspiratory work(Wip) were observed respectively, with the increasing assist level. The inspiratory muscles assessed by Wip were more unloaded at PS compared with PA [PS: (1.59±1.27) J/min vs PA: (4.99±3.48) J/min P<0.01]. However, the Wex was significantly higher with PS+ than with PA+ [PS+ : (1.17±0.54) J/min vs PA+ : (0.49±0.56)J/min, P<0.01]. The AI was increased with the increasing assist level of PSV [PS-: (0.46±0.57)%, PS: (1.36±1.24)% PS+ : (5.26±4.77)]. No asynchrony events were observed at PA- and PA. "Runaway" (expiratory asynchrony) was observed during PA+ [AI: (2.62±2.72)%]. Conclusions: Noninvasive-PAV can increase the Vt and decrease the Wip of the COPD patients with hypercapnia and avoid the over-assistance. The "Runaway" will occur at assist level higher than that set by tolerance. Physiological data can monitor the patient's responses and the ventilator-patient interaction, which may provide objective criteria for ventilator setting.

Efficient treatment of chronic respiratory failure associated with morbid obesity

Severe obesity sometimes leads to chronic respiratory failure. This condition is termed obesity-hypoventilation or Pickwickian syndrome. This article reports clinical observation illustrating effectiveness of noninvasive pressure support ventilation for the treatment of hypercapnic respiratory failure in a patient with morbid obesity. The treatment strategies for such patients are discussed.

Physiological Significance of Well-tolerated Inspiratory Pressure to Chronic Obstructive Pulmonary Disease Patient with Hypercapnia During Noninvasive Pressure Support Ventilation

ABSTRACTThe inspiratory pressure is often set by tolerance of chronic obstructive pulmonary disease (COPD) patient during noninvasive pressure support ventilation (PSV). However, physiological effects of this setting remain unclear. This study was undertaken to assess the physiological effect of highest tolerated assist level on COPD patient. The baseline inspiratory pressure (PS) was titrated by tolerance in 15 severe COPD patients with hypercapnia during acute exacerbation. In addition to the baseline PS, an additional decrease by 25% (PS− = 75% PS) or increase by 25% (PS+ = 125% PS) of PS was applied to the patients. Each level lasted at least 20 minutes. Respiratory rate (RR), tidal volume (Vt), inspiratory effort (PTPpesin/min), and neuro-ventilatory coupling (VE/RMS%) were measured. Asynchrony Index (AI) was calculated. The Vt and VE/RMS% were significantly increased by PS level (Vt: 561 ± 102 ml, VE/RMS%: 1.06 ± 0.42 L/%, comfort score: 7.5 ± 1.1). The inspiratory muscles were sufficiently unloaded (PTPpesin/min 56.67 ± 32.71 cmH2O.S/min). In comparison with PS, PS+ resulted in a further increase in Vt, VE/RMS% and AI (P < 0.01), with no further reduction in neural drive (RMS) and respiratory muscle activity (P > 0.05). Increasing inspiratory pressure significantly enhances the VE/RMS% and Vt. However, the inspiratory pressure higher than COPD patient's most tolerated level cannot lead to further reduction in respiratory muscle load and RMS, but more asynchrony events. Physiological data can monitor the patient's responses and the ventilator-patient interaction, which may provide objective criterion to ventilator setting.

Physiological Effect of the Pressure Support Set by the Chronic Obstructive Pulmonary Disease Patient's Comfort During Noninvasive Pressure Support Ventilation

Physiological Effect of the Pressure Support Set by the Chronic Obstructive Pulmonary Disease Patient's Comfort During Noninvasive Pressure Support Ventilation

36th International Symposium on Intensive Care and Emergency Medicine : Brussels, Belgium. 15-18 March 2016.

36th International Symposium on Intensive Care and Emergency Medicine : Brussels, Belgium. 15-18 March 2016.