Average Volume-assured Pressure Support Mode Research Articles

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.

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):

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.

Response of Home-Use Adaptive Pressure Modes to Simulated Transient Hypoventilation.

Adaptive servoventilation (ASV) is a recently developed ventilation mode designed to stabilize ventilation in patients with central sleep apnea and Cheyne-Stokes respiration. Alternatively, modes aiming to maintain average ventilation over several breaths, such as average volume-assured pressure support (AVAPS) and intelligent volume-assured pressure support (iVAPS), could be efficient during ventilation instability by reducing central events. These modes are available on a variety of devices. This bench evaluation studied the response of these different modes and devices to simulated transient hypoventilation events. Three home ventilation devices operating in ASV modes (AirCurve S10 VAuto, ResMed; DreamStation autoSV, Philips; Prisma CR, Löwenstein) and 2 ventilators with the AVAPS mode (DreamStation BiPAP, Philips; Lumis iVAPS, ResMed) were evaluated during transient central hypopnea/hypoventilation simulations characterized by a constant breathing frequency of 15 breaths/min and a progressive decrease of tidal volume (VT) from 500 mL to 50 mL, in 18, 12, 9, and 6 breaths, respectively, followed by a progressive return to the baseline at the same rate. The AirCurve S10 VAuto reacted to a VT decrease between 80% and 50% of baseline VT. DreamStation BiPAP and Prisma CR reacted when VT decreased to between 60% and 30% of baseline VT, whereas the AVAPS response to hypopnea occurred during the crescendo phase of hypopnea/hypoventilation VT. The iVAPS response was between that of the AirCurve S10 VAuto and the other ASV devices. Among the ASV devices, the minimum VT was higher with AirCurve S10 VAuto, followed by the Prisma CR and the DreamStation BiPAP. Minimum VT was not influenced by AVAPS and was improved by iVAPS without outperforming the AirCurve S10 VAuto. Maximum VT was increased by iVAPS, whereas ASV devices did not induce a significant VT overshoot. ASV devices improved central hypopnea/hypoventilation events without inducing hyperpnea events and therefore were better adapted than AVAPS and iVAPS devices, with notable differences in their responses to hypoventilation events.

Noninvasive auto-titrating ventilation (AVAPS-AE) versus average volume-assured pressure support (AVAPS) ventilation in hypercapnic respiratory failure patients.

Auto-titrating noninvasive ventilation (NIV) has been developed as a new mode applying variable expiratory-positive airway pressure (EPAP) in addition to variable inspiratory pressures (IPAP), both to deliver targeted tidal volume (VT) and to eliminate upper airway resistance. The purpose of this study is to evaluate whether NIV with auto-titrating mode will decrease more PaCO2 within a shorter time compared to volume-assured mode in hypercapnic intensive care unit (ICU) patients. The hypercapnic respiratory failure patients treated with average volume assured pressure support- automated EPAP mode (group1) were compared with those treated with average volume-assured pressure support mode (group2). Two groups were matched with each other according to baseline diagnoses, demographic characteristics, arterial blood gas values, target VT settings and daily NIV usage times. Built-in software was used to gather the ventilatory parameters. Twenty-eight patients were included in group 1, and 22 in group 2. The decrease in PaCO2 had been achieved within a shorter time period in group 1 (p < 0.05). This response was more pronounced within the first 6h (mean reduction in PaCO2 was 7 ± 7mmHg in group 1 and 2 ± 5mmHg in group 2, p = 0.025), and significantly greater reductions in PaCO2 (18 ± 11mmHg in group 1 and 9 ± 8mmHg in group 2, p = 0.008) and plasma HCO3 levels (from 32 to 30mEq and from 35 to 35mEq, p = 0.007) took place within first 4days. While mean IPAP was similar in both groups, maximum EPAP, mean VT and leak were significantly higher in group 1 than in group 2 (p < 0.05). Results of this preliminary study suggest that, this new auto-titrating NIV mode may provide additional benefit on volume-assured mode in decreasing PaCO2 more efficiently and rapidly in hypercapnic ICU patients.

P146 The patients with acute exacerbation of COPD maybe benefit from autotitrating EPAP during noninvasive ventilation: a prospective study

Introduction To determine whether the patients with acute exacerbation of COPD benefit from noninvasive ventilation, which EPAP is required for a varying range rather than a fixed level. Methods A randomized,prospective and controlled study, 30 elderly patients in AECOPD were divided into three groups: S/T(spontaneous/time) mode group, AVAPS(average volume assured pressure support) mode group and AVAPS-AE(average volume assured pressure support auto-EPAP) mode group. Each group was accepted noninvasive ventilation therapy (NIV via total face mask), for a period of 48 hours. Parameters in three NIV modes: S/T group(IPAP=18 cmH2O, EPAP =5cmH2O,tidal volume depending on individual BMI); the same adopted in AVAPS mode; AVAPS-AE mode(maximum EPAP=8cmH2O,minimum EPAP=4cmH2O, tidal volume depending on individual BMI) .The arterial blood gas analysis was observed at different time(the 0.5th, 1 st, 2 nd, 24 th and 48 th hour).During the NIV, RR, HR and Borg score were monitored and recorded continuosly. Degree of patients' comfort was measured by the VAS (Visual Analog Scale,0～10). Results 1. The 0.5th, 1st, and 2nd hours after NIV treatment, there was a greater decrease in PCO2 and increase in PO2 and PH during AVAPS-AE mode than two other modes(p< 0.05). RR, HR and Borg score in AVAPS-AE mode had a greater changes than others(p< 0.05). Compared with the S/T and AVAPS group, the recovery duration of shortness in AVAPS-AE group was significantly shorter than two others (p< 0.05). 2. During the whole NIV period, the main result was a higher VAS score in AVAPS-AE mode than others (p< 0.05). 3 cases with patient-ventilator asynchrony occurred in S/T group, 3 cases and 1 case happened in AVAPS group and AVAPS-AE group respectively. Conclusions Autotitrating EPAP during noninvasive ventilation support could be adjust to changing levels of PEEP in AECOPD patients. AVAPS-AE mode maybe more likely to relieve shortness quickly,especially in synchronization and comfort,worthy of promotion, and it may play an important role in improving dynamic hyperinflation of patients with AECOPD.

Positive outcome of average volume-assured pressure support mode of a Respironics V60 Ventilator in acute exacerbation of chronic obstructive pulmonary disease: a case report.

IntroductionWe were able to treat a patient with acute exacerbation of chronic obstructive pulmonary disease who also suffered from sleep-disordered breathing by using the average volume-assured pressure support mode of a Respironics V60 Ventilator (Philips Respironics: United States). This allows a target tidal volume to be set based on automatic changes in inspiratory positive airway pressure. This removed the need to change the noninvasive positive pressure ventilation settings during the day and during sleep. The Respironics V60 Ventilator, in the average volume-assured pressure support mode, was attached to our patient and improved and stabilized his sleep-related hypoventilation by automatically adjusting force to within an acceptable range.Case presentationOur patient was a 74-year-old Japanese man who was hospitalized for treatment due to worsening of dyspnea and hypoxemia. He was diagnosed with acute exacerbation of chronic obstructive pulmonary disease and full-time biphasic positive airway pressure support ventilation was initiated. Our patient was temporarily provided with portable noninvasive positive pressure ventilation at night-time following an improvement in his condition, but his chronic obstructive pulmonary disease again worsened due to the recurrence of a respiratory infection. During the initial exacerbation, his tidal volume was significantly lower during sleep (378.9 ± 72.9mL) than while awake (446.5 ± 63.3mL). A ventilator that allows ventilation to be maintained by automatically adjusting the inspiratory force to within an acceptable range was attached in average volume-assured pressure support mode, improving his sleep-related hypoventilation, which is often associated with the use of the Respironics V60 Ventilator. Polysomnography performed while our patient was on noninvasive positive pressure ventilation revealed obstructive sleep apnea syndrome (apnea-hypopnea index = 14), suggesting that his chronic obstructive pulmonary disease was complicated by obstructive sleep apnea syndrome.ConclusionIn cases such as this, in which patients with severe acute respiratory failure requiring full-time noninvasive positive pressure ventilation therapy also show sleep-disordered breathing, different ventilator settings must be used for waking and sleeping. On such occasions, the Respironics V60 Ventilator, which is equipped with an average volume-assured pressure support mode, may be useful in improving gas exchange and may achieve good patient compliance, because that mode allows ventilation to be maintained by automatically adjusting the inspiratory force to within an acceptable range whenever ventilation falls below target levels.