Average Volume Assured Pressure Support Research Articles

Adaptive non‐invasive ventilation treatment for sleep Apnea

AbstractThe purpose of this study was to investigate the effectiveness of two non‐invasive mechanical ventilation (NIV) modalities to treat sleep apnea: (1) Average Volume Assured Pressure Support (AVAPS) NIV, and (2) Pressure Support (PS) NIV with Continuously Calculated Average Required Ventilation (CCARV). Two detailed (previously developed and tested) simulation models were used to assess the effectiveness of the NIV modalities. One simulated subjects without chronic obstructive pulmonary disease (COPD), and the other simulated patients with COPD. Sleep apnea was simulated in each model (COPD and Non‐COPD), and the ability of each NIV modality to normalize breathing was measured. In both NIV modalities, a low level continuous positive airway pressure was used and a backup respiratory rate was added to the algorithm in order to minimize the respiratory work rate. Both modalities could help normalize breathing in response to an episode of sleep apnea within about 5 min (during which time blood gases were within safe limits). AVAPS NIV and PS NIV with CCARV have potential value to be used for treatment of sleep apnea. Clinical evaluations are needed to fully assess the effectiveness of these NIV modalities.

Effect of Non-Invasive Mechanical Ventilation with Average Volume Assured Pressure Support (AVAPS) in Patients with Chronic Obstructive Pulmonary Disease with Acute Exacerbation

Background: Patients with acute respiratory failure have traditionally been evaluated for non-invasive mechanical ventilation (NIV) based on clinical evaluation and changes in blood gases, with NIV support pressures manually adjusted by an operator. Bilevel positive airway pressure-spontaneous/timed (BiPAP S/T) with average volume assured pressure support (AVAPS) uses a fixed tidal volume that automatically adapts to a patient's needs. Objective: To see the effective of non-invasive mechanical ventilation with average volume assured pressure support (AVAPS) in patients with chronic obstructive pulmonary disease with acute exacerbation. Materials and Methods: This single-center prospective study was carried out at the Gazi Medical College (GMC), Khulna, Bangladesh, in the department of medicine. The research's participants were all admitted between December 1, 2021, and January 1, 2023. The trial included all patients with acute exacerbations of chronic obstructive pulmonary disease. Age, gender, and disease severity were determined using the APACHE II scoring system. A structured proforma was used to collect data. The percentage and absolute number were used to express all category data. All numerical continuous data were reported as mean standard deviation. SPSS version 23 was used to analyze the data. All tests were evaluated using a 95% confidence interval, and a P value of 0.05 was deemed significant. Results: The mean MBS, NRS, dyspnea/comfort scale, respiration rates, systolic blood pressure, and diastolic blood pressure- post treatment were statistically significant (p <0.05) when compared to pretreatment in the BiPAP S/T with AVAPS group. Mean PaCO2, MBS, NRS, dyspnea/comfort scale, heart rate, respiration rates, and systolic blood pressure- post treatment were statistically significant (p <0.05) when compared to pretreatment in the BiPAP S/T group. Conclusion: BiPAP S/T with AVAPS promotes a quicker return to awareness in patients with chronic .......

Average Volume-assured Pressure Support as Rescue Therapy after CPAP Failure in Pediatric Obstructive Sleep Apnea: A Retrospective Case Series Study.

Continuous positive airway pressure (CPAP) is frequently prescribed for patients with residual obstructive sleep apnea (OSA) following adenotonsillectomy. The goal was to examine the efficacy of noninvasive ventilation with average volume-assured pressure support (AVAPS) as a potential option for children with failed CPAP titration. In a single-center retrospective study, we included children aged 1-17 years, with polysomnographically confirmed OSA who underwent AVAPS titration following failed CPAP titration. In addition to describing the clinical characteristics of the included patients, we compared polysomnographic parameters before and after AVAPS. Nine patients met the inclusion criteria; out of them, 8 (89%) were males with an age range of 6.7 ± 3.9 years and a body mass index percentile of 81.0 ± 28.9. Reasons for failed CPAP titration were: 3 (33%) patients due to inability to control apnea-hypopnea index (AHI), 3 (33%) patients due to sleep-related hypoventilation, 2 (22%) patients due to treatment-emergent central sleep apnea, and 1 (11%) patient due to intolerance to CPAP. AVAPS resulted in a greater reduction in AHI than CPAP (reduction following CPAP = 24.6 ± 29.3, reduction following AVAPS = 42.5 ± 37.6, p = 0.008). All patients had resolution of the problems which caused CPAP failure. In this case a series of children with OSA and with failed CPAP titration, AVAPS resulted in a greater reduction in AHI compared with CPAP as well as resolution of the problems which caused CPAP failure.

Moving toward standardization: physician reporting of sleep studies.

Lastra AC, Ingram D, Park J, etal. Moving toward standardization: physician reporting of sleep studies. J Clin Sleep Med. 2023;19(3):595-603.

Role of Average Volume Assured Pressure Support Mode (AVAPS) in the Management of Acute Exacerbation of Chronic Obstructive Pulmonary Disease With Type 2 Respiratory Failure.

Background Non-invasive ventilation (NIV) is a well-established approach in the treatment of acute exacerbation of chronic obstructive pulmonary disease (COPD) with type 2 respiratory failure. Average volume-assured pressure support (AVAPS) mode integrates the characteristics of both volume and pressure-controlled modes of NIV. In bilevel positive airway pressure (BiPAP) mode, volume is the dependent variable, whereas in AVAPS mode, pressure is the dependent variable. In this study, we aimed to compare the role of AVAPS mode with BiPAP spontaneous/timed (S/T) mode for the management of patients with acute exacerbation of COPD with type 2 respiratory failure. Methodology A hospital-based comparative and analytical study was carried out on 100 patients with acute exacerbation of COPD with type 2 respiratory failure admitted to respiratory disease hospital, Sardar Patel Medical College, Bikaner (Rajasthan, India). Patients were randomly divided into two groups of 50 patients each. Group A patients were treated with AVAPS mode and group B patients with BiPAP (S/T) mode. Arterial blood gases, average duration of hospital stay, and need for invasive mechanical ventilation were compared between the two groups. Results There was a statistically significant difference in favor of group A in terms of improvement in pH andpCO2as compared to group B at 6 h (pH, p=0.027; pCO2, p=0.012) and 24 h (pH, p=0.032; pCO2, p=0.013). The duration of hospital stay was found to be lower in group A(p=0.003). However, no significant difference was found in terms of need for invasive mechanical ventilation between both groups (p=0.338). Conclusion Application of AVAPS mode results inmore rapid and steady improvement inpatients of COPD as compared to BiPAP (S/T) mode. Thus, managementthrough non-invasive ventilation AVAPS mode should be considered inpatients with acute exacerbation of COPD with type 2 respiratory failure.

Noninvasive Mechanical Ventilation with Average Volume-Assured Pressure Support versus BiPAP S/T in De Novo Hypoxemic Respiratory Failure.

Background Bilevel positive airway pressure in spontaneous/time and average volume-assured pressure support (BiPAP·S/T–AVAPS) could maintain an adequate tidal volume by reducing the patient's inspiratory effort; however, this ventilatory strategy has not been compared with other ventilatory modes, especially the conventional BiPAP S/T mode, when noninvasive mechanical ventilation (NIMV) is used. The primary objective of this study was to determine the rate of success and failure of the use of BiPAP·S/T-AVAPS versus BiPAP·S/T alone in patients with mild-to-moderate “de novo” hypoxemic respiratory failure. Methods This was a matched-cohort study. Subjects with mild-to-moderate de novo hypoxemic respiratory failure were divided into two groups according to the ventilatory strategy used. The subjects in the BiPAP·S/T group were paired with those in the BiPAP·S/T-AVAPS group. Results A total of 58 subjects were studied. Twenty-nine subjects in the BiPAP·S/T group were paired with 29 subjects in the BiPAP·S/T-AVAPS group. Twenty patients (34.5%) presented with “failure of NIMV,” while 38 (65.5%) patients did not. In addition, 13 (22.4%) patients died, while 45 (77.6%) recovered. No differences were found in the percentage of intubation (P=0.44) and mortality (P=0.1). Conclusion The BiPAP S/T-AVAPS ventilator mode was not superior to the BiPAP·S/T mode. A high mortality rate was observed in patients with NIMV failure in both modes. This trial is registered with https://doi.org/10.1186/ISRCTN17904857.

Average volume-assured pressure support for patients with obstructive sleep apnea with failed CPAP titration.

ObjectivesObstructive sleep apnea (OSA) is a common disease, often treated using continuous positive airway pressure (CPAP) therapy. In many cases, patients fail a CPAP titration study due to inadequate control of the apnea-hypopnea index (AHI, events/hour) or due to treatment-emergent central sleep apnea (TE-CSA). We report our experience using a mode of non-invasive ventilation for alternative treatment of these patients.Material and MethodsWe reviewed records of adults who had OSA with AHI≥15 diagnosed on polysomnography (PSG) with failed CPAP titration and in whom titrations with average volume-assured pressure support (AVAPS) with auto-titrating expiratory positive airway pressure were performed.ResultsForty-five patients, age 57.9±13.1 y, 26 males, body mass index (BMI) 40.2±8.7kg/m2. Reasons for CPAP titration failure included: TE-CSA (25, 55.6%) and inadequate control of AHI at maximum CPAP of 20cm H2O (20, 44.4%). Changes noted from baseline PSG to AVAPS titration: AHI: 65.3±29.3 decreased to 22.3±16.1 (p<0.001). Median time SpO2 ≤88%: 63.7 to 6.9min (p<0.001). In 16 patients the AHI was reduced to <15 and in 16 additional patients the AHI was reduced to <30. Improvement in AHI was not related to gender, age, or opioid use, but was correlated with BMI: ∆AHI=12.2 - (1.4 * BMI); p=0.05. AVAPS resulted in improved sleep architecture: median N3 sleep increased: 1.4% to 19.6% total sleep time (TST) (p<0.001), and median R sleep increased: 6.4% to 13.6% TST (p<0.01).DiscussionFor patients with OSA for whom CPAP titration failed, titration with AVAPS may be an effective treatment.

0837 Average Volume-Assured Pressure Support (AVAPS) after CPAP Failure in A Pediatric Patient with Severe Obstructive Sleep Apnea and Sleep-Related Hypoventilation

Abstract Introduction Obstructive sleep apnea (OSA) has become an increasingly pervasive sleep disorder in the pediatric population. Current mainstream treatments include adenotonsillectomy and positive airway pressure therapy. Average volume-assured pressure support (AVAPS) is a relatively new mode of non-invasive ventilation, which has been increasingly used in the treatment of respiratory failure and hypoventilation syndromes. Here we present a case of a pediatric patient with severe OSA and sleep-related hypoventilation who was successfully treated with AVAPS after failure of CPAP therapy. Report of Cases: A four year old boy with history of severe OSA, severe obesity, asthma, and allergic rhinitis underwent polysomnography one year after adenotonsillectomy and nasal turbinate reduction due to continued symptoms of sleep-disordered breathing. Results showed elevated residual apnea-hypopnea index (AHI = 30.4 events/hour), sleep-related hypoventilation (T ETCO2≥50 = 228.3 minutes), and sleep-related hypoxemia (T≤90% = 7 minutes). Therefore the patient underwent repeated adenotonsillectomy and turbinate reduction, with post-operative course complicated by pulmonary edema requiring intubation. He was extubated and weaned to nocturnal CPAP. Following discharge, CPAP titration failed to control AHI at maximal pressure (AHI 54.5 on 20 cm H2O, T≤90% = 15.3 minutes). The patient was then started on AVAPS with auto-titrating EPAP (AVAPS-AE, settings Pmax 20 cm H2O, PS 2-10 cm H2O, EPAP 5-10 cm H2O, RR auto, room air) with subsequent improvement of snoring and witnessed apneas, as well as reduction of daytime sleepiness. Afterwards, AVAPS-AE titration confirmed resolution of obstructive sleep apnea, sleep-related hypoxemia, and sleep-related hypoventilation (AHI = 2.5, T≤90% = 1.2 minutes, T ETCO2 ≥50 = 6.5 minutes.) The patient has since remained stable on AVAPS-AE until age ten, with the most recent AVAPS titration demonstrating continued resolution of sleep-disordered breathing. Conclusion AVAPS was an effective treatment for a pediatric patient with severe OSA and sleep-related hypoventilation who had failed CPAP therapy. Support (If Any) None.

0859 AVAPS to the rescue: A case of severe obstructive sleep apnea with treatment resistant to UPPP and CPAP in a pediatric patient with Prader-Willi syndrome

Abstract Introduction Prader-Willi syndrome (PWS) has a prevalence of 1/10,000 to 1/30000 and is the most common syndromic form of obesity. Prader-Willi syndrome is defined by a multitude of features that develop from early childhood to adolescents, but one of the primary developments is obesity in the setting of hyperphagia during early childhood. Due to the development of obesity, there is a high prevalence of obstructive sleep apnea (OSA) among PWS patients. Report of Cases: A 6-year-old boy with PWS with a 2-year history of loud snoring underwent polysomnography (PSG) which showed severe OSA with Apnea-Hypopnea Index (AHI, events/h) 133.7. The patient underwent surgical intervention with a combined uvulopalatopharyngoplasty and adenotonsillectomy and a follow up PSG showed a residual AHI of 37. On CPAP titration the AHI improved to 1.2 with CPAP 14 cm H2O and the patient was discharged on home nasal CPAP. Over the next several years, the patient had suboptimal CPAP compliance. At 11 years of age, the patient was admitted to the intensive care unit (ICU) with volume overload –with a normal cardiac workup- and respiratory failure requiring high flow nasal cannula oxygen. Venous blood gas (VBG) showed pH 7.34 and severe hypercapnia with pCO2 73 mmHg c/w obesity hypoventilation syndrome (OHS). The patient was started on CPAP then changed to bilevel PAP ST with supplemental oxygen. Due to persistent hypercapnia in the high 60s noninvasive ventilation (NIV) was switched to Average Volume-assured Pressure Support with auto titrating EPAP (AVAPS-AE) with significant improvement in hypercapnia and overall tolerance. Discharge VBG showed pH 7.35 and PCO2 56 mm Hg. The patient was discharged home, is doing well and has avoided readmission for at least 6 months. Conclusion This case highlights the potential for newer modes of noninvasive ventilation with autotitrating EPAP to treat severe OSA with OHS and hypercapnic respiratory failure in patients with PWS and other conditions. With the growing obesity epidemic, rates of treatment failures with CPAP and traditional bilevel PAP therapy may increase and consideration of alternative modes of NIV therapy should be considered. Support (If Any)

0529 Average volume-assured pressure support as rescue therapy after CPAP failure in pediatric obstructive sleep apnea

Abstract Introduction Average volume-assured pressure support with autotitrating EPAP (AVAPS-AE) is an automatically titrating mode of noninvasive ventilation (NIV) which provides a targeted tidal volume through adjustment of inspiratory pressures within a set range. In pediatric obstructive sleep apnea (OSA), adenotonsillectomy (AT) is often the first-line treatment and CPAP is often poorly tolerated as an alternative. We aimed to evaluate the efficacy of AVAPS as a potential option for children in whom CPAP titration is unsuccessful. Methods Retrospective review of records of children diagnosed with OSA with failed CPAP titration and in whom an in-laboratory AVAPS titration was performed. Results A total of 9 patients with OSA (8 male, age (95% CI) = 6.7 ± 2.6, BMI percentile (95% CI) = 81.0 ± 18.9) were identified. Of these patients, 6 had prior AT. All 9 patients had failed CPAP titration prior to AVAPS titration: 3 failed due to inability to control the apnea-hypopnea index (AHI, events/hour), 2 due to persistent hypercapnia, 2 due to treatment-emergent central sleep apneas, and 2 due to pressure intolerance. All 9 patients showed improvement in AHI following AVAPS titration (mean change = -17.9, 95% CI = 17.9 ± 9.5) as well as improvement in AHI from initial PSG to AVAPS titration (mean change = -42.5, 95% CI = 42.5 ±24.6). 7 patients had reduction in total sleep time with oximetry recording below 90% (T&amp;lt;90) from CPAP to AVAPS titration (mean change = -4.7 minutes, 95% CI = 4.7 ± 14.7), while 8 patients had reduction in T&amp;lt;90 from initial PSG to AVAPS titration (mean change = -14.0 minutes, 95% CI = 14.0 ±24.5). 7 patients had increase in REM sleep from CPAP to AVAPS titration (mean change = +15.9 minutes, 95% CI = 15.9 ±18.3), while 6 patients had increase in REM sleep from initial PSG to AVAPS titration (mean change = +7.7 minutes, 95% CI = 7.7 ±26.6). Conclusion In this case series of children with OSA and with failed CPAP titration, AVAPS is an effective treatment modality. Support (If Any)

Pediatric Average Volume Assured Pressure Support.

Average volume assured pressure support (AVAPS) is a modality of non-invasive ventilation that enables the machine to deliver a pre-set tidal volume by adjusting the inspiratory pressure support within a set range. Data on its use in the pediatric population are limited to case reports and single centre case series. This article reviews paediatric data on use of AVAPS and highlights the need for validation to help develop specific guidelines on use of AVAPS in children.

Apnea-Hypopnea Index in Chronic Obstructive Pulmonary Disease Exacerbation Requiring Noninvasive Mechanical Ventilation with Average Volume-Assured Pressure Support

Introduction This study intends to determine the Apnea-Hypopnea Index in patients hospitalized with acute hypercapnic respiratory failure from chronic obstructive pulmonary disease exacerbation, who require noninvasive ventilation with average volume-assured pressure support (AVAPS), as well as describes the clinical characteristics of these patients. Materials and Methods We designed a single-center prospective study. The coexistence of Apnea-Hypopnea Index and clinical, gasometric, spirometric, respiratory polygraphy, and ventilatory characteristics were determined. The clinical characteristics found were categorized and compared according to the Apnea-Hypopnea Index (AHI) < 5, AHI 5–15, and AHI >15. A p value <0.05 was considered statistically significant. Results During the study period, a total of 100 patients were admitted to the ICU with a diagnosis of acute hypercapnic respiratory failure due to COPD exacerbation. 72 patients presented with acute respiratory failure and fulfilled criteria for ventilatory support. Within them, 24 received invasive mechanical ventilation and 48 NIV. After applying the inclusion criteria for this study, 30 patients were eligible. An AHI >5 was present in 24 of the 30 patients recruited (80%). Neck circumference (cm), Epworth scale, and Mallampati score evidenced significant differences when compared to the patient's AHI <5, AHI 5–15, and AHI >15 (p < 0.05). Furthermore, patients with an AHI >5 had longer hospital admissions, prolonged periods on mechanical ventilation, and a higher percentage of intubation rates. Conclusion Apnea-Hypopnea Index and chronic obstructive pulmonary disease exacerbation are a frequent association found in patients with acute hypercapnic respiratory failure and COPD exacerbations that require NIV. This association could be a determining factor in the response to NIV, especially when AVAPS is used as a ventilatory strategy.

NON-INVASIVE VENTILATION WITH AVERAGE VOLUME-ASSURED PRESSURE SUPPORT FOR ACUTE HYPERCAPNIC RESPIRATORY FAILURE

TOPIC: Critical Care TYPE: Medical Student/Resident Case Reports INTRODUCTION: Average volume-assured pressure support (AVAPS) is a comparatively newer modality of non-invasive ventilation that incorporates the properties of both volume and pressure-control ventilation. Though its benefits were well documented in chronic respiratory failure, studies illustrating its usage in acute respiratory failure are still insubstantial. Herein, we aim to showcase the utility of AVAPS in the management of acute on chronic hypercapnic respiratory failure. CASE PRESENTATION: An 80-year-old female with a body mass index (BMI) of 37 kg/m2 and chronic opiate use presented to the Emergency Department (ED) following a two-day history of increasing shortness of breath and confusion. Her medical history was notable for hypersensitivity pneumonitis secondary to bird exposure, former smoker, paroxysmal atrial fibrillation, and recent acute pericarditis for which she is taking aspirin and colchicine. An arterial blood gas (ABG) showed a pH of 7.14, PaCO2 of 124 mmHg (FiO2 28%), PaO2 of 94 mmHg, and bicarbonate of 41 mmol/L. A chest x-ray showed increased bilateral interstitial infiltrates. The patient received IV methylprednisolone and was placed on Spontaneous/Timed mode Bilevel positive airway pressure (BiPAP S/T) with an Inspiratory positive airway pressure (IPAP) of 10 mmHg, Expiratory positive airway pressure (EPAP) of 5 mmHg, and a respiratory rate of 12/min. At these set pressures, her inspired tidal volumes were around 400ml. The patient continued to remain confused (GCS 12/15) and thus, she was switched to average volume-assured pressure support (AVAPS) with a target tidal volume of 500ml. With this modality, she displayed rapid improvement in her symptoms and an ABG drawn eight hours after initiation revealed a pH of 7.34, PaO2 of 66 mmHg, PaO2 of 135 mmHg (FiO2 50%), and bicarbonate of 34 mmol/L. The patient was discharged home on the 5th day after admission. DISCUSSION: AVAPS is an intelligent modality of non-invasive pressure support that gives us the option to set a maximum and a minimum IPAP, in place of one fixed IPAP setting, along with a target tidal volume. The ventilator automatically adjusts the inspiratory pressure within the set range to ensure the delivery of pre-set tidal volume. Patient-ventilator dyssynchronization is prevented and previous studies have reported better patient comfort and satisfaction with AVAPS, thereby, improving patient compliance to the treatment. AVAPS was shown to be superior to BiPAP S/T and associated with a rapid improvement of ABG values and GCS score in patients with acute hypercapnic respiratory failure complicated with hypercapnic encephalopathy (GCS <10/15). CONCLUSIONS: Our case highlights the valuable utility of AVAPS and how, in certain clinical situations, it may be a preferred first-line modality over standard BiPAP S/T for the treatment of acute hypercapnic respiratory failure. REFERENCE #1: Yarrarapu SNS, Saunders H, Sanghavi D. Average Volume-Assured Pressure Support. 2021 Jan 5. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan–. PMID: 32809435. DISCLOSURES: No relevant relationships by Pramod Guru, source=Web Response No relevant relationships by Devang Sanghavi, source=Web Response No relevant relationships by Hollie Saunders, source=Web Response No relevant relationships by Siva Naga Yarrarapu, source=Web Response

Comparison of BPAP S/T and Average Volume-Assured Pressure Support Modes for Hypercapnic Respiratory Failure in the Emergency Department: A Randomized Controlled Trial.

Background: There is limited research into the utility of average volume-assured pressure support (AVAPS), a volume-assured pressure-controlled mode, especially in patients with hypercapnic respiratory failure. Aims: This study aimed at a randomized comparison of AVAPS and bilevel positive airway pressure spontaneous/timed (BPAP S/T) modes in non-invasive mechanical ventilation (NIMV) application with hypercapnic respiratory failure patients in the emergency department (ED).Study Design: Randomized controlled study.Methods: In this prospective randomized controlled study, 80 patients admitted to ED with hypercapnic respiratory failure requiring NIMV were randomly assigned to AVAPS or S/T groups using the sealed envelope method (33 patients in the S/T group, 47 patients in the AVAPS group). Data of arterial blood gas (ABG), vital parameters, Glasgow Coma Score (GCS), additional treatment needs, and clinical outcomes were evaluated, and the treatment success rates of both groups were compared. Results: A total of 80 patients, 33 in the S/T and 47 in the AVAPS group, were analyzed in the study. The pH values improved in the AVAPS group compared to the baseline (0.07 [0.04-0.10] vs 0.03 [0.00-0.11]). PaCO2 (partial pressure of carbon dioxide) excretion was faster in the AVAPS group than in the S/T group in the first hour (10.20 mmHg [6.20-19.20] vs. 4.75 ([-] 0.83-16.88)). The comparison of blood gas measurements showed no significant differences between the groups regarding the changes in PaCO2 and pH values over time (P = .141 and P = .271, respectively). During the ED follow-up, 3 (6.4%) patients in the AVAPS group and 5 (15.2%) patients in the S/T group needed intubation [Relative risk: 0.42 (95% CI: 0.11 to 1.64), P = .21].Conclusion: In this study, improvements in blood gas parameters in the AVAPS group were faster compared to the S/T group; however, we did not find any significant difference between the groups in terms of clinical parameters. The AVAPS mode is as effective and safe as BPAP S/T in treating patients with hypercapnic respiratory failure in the ED.

Treatment of critically ill patients with acute hypercarbic respiratory failure by average volume‐assured pressure support mode

Average volume-assured pressure support (AVAPS), a dual mode, delivers a set tidal volume (TV) per kg by adjusting the pressure between upper and lower inspiratory positive airway pressures (IPAP). Thus, ventilation is presumed to be happened effectively by sending a guaranteed TV. This study was aimed to evaluate the effectiveness of AVAPS mode in critically ill patients with acute hypercarbic respiratory failure (HRF) and compare the results with bilevel positive airway pressure-spontaneous/timed (BPAP-S/T) mode. Sixty patients were assigned to BPAP-S/T (n=29) and AVAPS modes (n=31). Maximum IPAP was started at 20 cmH2 O and minimum IPAP was set at 5 cmH2 O higher than expiratory positive airway pressure (EPAP) in AVAPS mode. IPAP was started at 15 cmH2 O in BPAP-S/T mode. IPAP levels were titrated up to 30 cmH2 O during noninvasive mechanic ventilation (NIMV) with a targeted TV of 6-8 mL/kg. Patients were followed for 5 days. No differences were found in pH, paCO2 , HCO3 , TV and EPAP between the two groups when compared separately by days. Maximum IPAP levels were significantly high in AVAPS mode in all times (P<0.001). The length of stay (LOS) in intensive care unit (ICU) (P=0.994) and hospital (P=0.509), hours of NIMV use per day (P=0.101) and NIMV success rate (P=0.931) were identical between the two groups. ICU (P=0.931), hospital (P=0.800), 6-month (P=0.919) and 1-year (P=0.645) mortality rates were also not different between the both groups. AVAPS mode had similar efficiency with BPAP-S/T mode regarding the NIMV treatment success in critically ill patients with acute HRF.

Use of average volume-assured pressure support as a therapeutic option in patients with central sleep apnea syndrome.

Central sleep apnea (CSA) syndrome commonly occurs with other medical conditions such as congestive heart failure, opiate use, and brainstem disorders. Various treatment modalities have been used with varied effectiveness in an attempt to improve ventilation and reduce the apnea-hypopnea index (AHI) in patients with CSA. This study evaluated whetheror not a bilevel positive airway pressure mode of noninvasive ventilation, average volume-assured pressure support (AVAPS) is effective in treating CSA. This was a retrospective review of patients with CSA who underwent AVAPS titration studies at our institution. We included patients with CSA with apnea-hypopnea index (events/hour) (AHI) ≥ 15, and examined the effectiveness of AVAPS in reducing AHI, improving oxygenation parameters, and improving sleep architecture. There were 12 patients, withmeanage 62.8 ± 11.5years, body mass index (BMI) 33.5 ± 4.7kg/m2, 8 men, and Epworth Sleepiness Scale 9.3 ± 4.9. Five patients had CSA attributed to opiate use, 4 patients had CSA with Cheyne-Stokes respiration, and 3 patients had primary CSA. The only significant change from baseline PSG was AHI reduction with AVAPS: 63.3 ± 19.1 to 30.5 ± 30.3 (p < 0.003). In 5 patients (42%), AHI was reduced to < 15 with AVAPS use.Improvement in AHI was not related to gender, BMI, opiate use, or age. Defining response to therapy as AHI reduced to < 15, we found that lack of hypertension was the only significant predictor of response (p = 0.045). No significant changes in sleep architecture between the two studies were found. AVAPS is an effective mode of treating CSA in a significant proportion of patients. More studies are needed to confirm these findings and determine what factors are associated with response to therapy.

859 Trial of average volume-assured pressure support (AVAPS) to treat hypoventilation in a child with rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD) and systolic heart failure

Abstract Introduction ROHHAD syndrome is a rare disorder of respiratory control and autonomic nervous system regulation with endocrine abnormalities. Although children may present with obstructive sleep apnea, their blunted respond to hypoxemia and hypercapnia is a life-threating feature, often leading to cardiorespiratory arrest. There is limited literature regarding non-invasive positive pressure ventilation (NIPPV) in these children. We report a trial of AVAPS in a child with ROHHAD syndrome. Report of case(s) Our patient is a 6-year-old male with history of rapid weight-gain (49.9 kg in 2.5 years), type-2 diabetes, and mild OSA who presented to an outside hospital (OSH) in March 2020 with acute hypercapnic hypoxemic respiratory failure. He required bilevel PAP therapy, steroids, and bromocriptine for thermoregulatory dysfunction. His clinical presentation, along with negative PHOX2B gene mutation and absence of parenchymal lung disease on chest computerized tomography suggested a diagnosis of ROHHAD syndrome. Outpatient, he was successfully transitioned to empiric AVAPS therapy. In November 2020, he presented again to an OSH in hypercapnic hypoxemic respiratory failure with new systolic heart failure with ejection fraction of 28%. After clinical stabilization, he was transferred to our hospital on CPAP 10 cmH20 with 100% FiO2 for further management. Awake blood gas was consistent with chronic hypercapnic respiratory failure; therefore, the patient was placed initially on bilevel PAP therapy empirically until an inpatient bilevel PAP titration polysomnogram was conducted. The patient remained hypercapnic and was converted to continuous AVAPS therapy starting at a tidal volume of 8.6mL/kg based on ideal body weight. AVAPS was titrated until achieving adequate ventilation, but the patient was unable to tolerate continuous NIPPV. Because of his heart failure in the setting of expected worsening respiratory failure, the decision was made to pursue tracheostomy placement for invasive positive pressure ventilation. Conclusion ROHHAD syndrome is a rare disorder that begins within the first decade of life, making adherence to daytime NIPPV difficult. This case illustrates a trial of AVAPS in a child with ROHHAD syndrome prior to tracheostomy placement. It highlights the need for future research in advanced ventilatory support strategies in children. Support (if any):

848 Refractory Hypoventilation in Congenital Central Hypoventilation Syndrome: A Case for Average Volume-Assured Pressure Support

Abstract Introduction Congenital Central Hypoventilation Syndrome (CCHS) is a rare cause of alveolar hypoventilation in children resulting in lifelong ventilatory support. In older children requiring nocturnal support alone, the use of diaphragmatic pacing in conjunction with or independent of non-invasive ventilatory (NIV) support has been demonstrated to improve quality of life. We present a case of refractory hypoventilation despite escalation of NIV. Report of case(s) 20-year-old female with Hirschsprung’s disease and CCHS (20/26 polyalanine repeats) with history of invasive ventilation via tracheostomy who underwent bilateral diaphragmatic phrenic nerve stimulator placement at 13 years-of-age with subsequent tracheostomy decannulation. Diaphragmatic pacing was discontinued three years later in the setting of pneumonia and patient discomfort because of receiver positioning. At that time, she had improved subjective sleep quality and adequate ventilatory support on bi-level positive airway pressure (PAP) despite discontinuation of diaphragmatic pacing. Titration of bi-level PAP was done via polysomnogram four years later demonstrating nocturnal hypoventilation with transcutaneous CO2 values greater than 50 mmHg for 80% of the study and an oxygen nadir of 87% despite titration of inspiratory pressure and respiratory rate to maximize ventilatory assistance. The patient was subsequently admitted to the intensive care unit for transition to non-invasive average volume-assured pressure support (AVAPS) mode. Ventilation improved with nocturnal pCO2 values via capillary blood gas of 31 mmHg and 45 mmHg at 2 am and 6 am respectively. The patient was discharged on AVAPS therapy while undergoing evaluation to resume diaphragmatic pacing via cervical phrenic nerve stimulators for improved comfort. Conclusion Several ventilatory strategies may be employed in the care of patients with CCHS, with individualization of support based on phenotype, comorbidities, and patient and family preference. This case highlights the unique challenges of adequately ventilating patients as they age. The use of NIV via an AVAPS mode in patients with CCHS has been infrequently reported in the literature, though is promising in reported efficacy with regards to ensured ventilation. This, in conjunction with diaphragmatic pacing, may allow patients to achieve appropriate ventilation while maintaining quality of life, and could be considered in patients with refractory hypoventilation despite other modes of NIV. Support (if any):

Application of average volume assured pressure support (AVAPS) and ultrasound assessment in COVID-19 infection: real-life observation

article: Application of average volume assured pressure support (AVAPS) and ultrasound assessment in COVID-19 infection: real-life observation - Italian Journal of Emergency Medicine 2021 April;10(1):11-6 - Minerva Medica - Journals

Comment on "Average Volume-Assured Pressure Support Modes for Hypercapnic Respiratory Failure: Its Early Use in the Emergency Department".

Comment on "Average Volume-Assured Pressure Support Modes for Hypercapnic Respiratory Failure: Its Early Use in the Emergency Department".