Automatic adjustment of noninvasive pressure support with a bilevel home ventilator in patients with acute respiratory failure: a feasibility study

New noninvasive modalities in long-term pediatric ventilation: a scoping review

Long-term noninvasive ventilation modalities for the pediatric population have undergone a continuous evolution. Hybrid noninvasive ventilation modalities have been recently introduced in clinical practice. Combining the advantages of conventional ventilation, hybrid modes use algorithms that automatically adjust the ventilator's settings to achieve a predefined ventilation target. Most of the recommendations on the use and settings of hybrid noninvasive ventilation modalities in children are derived from adult experience. Therefore, there is a lack of evidence on its implementation in pediatric chronic respiratory diseases. This scoping review aims to map the existing information regarding the use of hybrid ventilation modalities in the pediatric population and identify knowledge or research gaps. We performed a literature search using MEDLINE and Pubmed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. We included 13 studies (ten studies on average volume-assured pressure-support ventilation; two studies on intelligent volume-assured pressure-support ventilation; and one study on adaptive servoventilation). The use of new noninvasive ventilation modes in the pediatric population has been applied for the treatment of neuromuscular and hypoventilation syndromes as an alternative therapeutic option in the case of the failure of conventional noninvasive ventilation. Their widespread use has been hampered by the limited evidence available. Longitudinal studies on a larger number of patients are needed to confirm their effectiveness and evaluate their long-term clinical and functional outcomes.

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

OBJECTIVES

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

AVAPS mode had similar efficiency with BPAP-S/T mode regarding the NIMV treatment success in critically ill patients with acute HRF.

Automatic EPAP intelligent volume-assured pressure support is effective in patients with chronic respiratory failure: A randomized trial

BACKGROUND AND OBJECTIVE

Patients with chronic respiratory failure are increasingly managed with domiciliary non-invasive ventilation (NIV). There may be limited ability to provide NIV titration for these complex patients, and ventilatory requirements and upper airway support needs may change over time. Therefore, an automatically adjusting expiratory positive airway pressure (AutoEPAP) algorithm may offer advantages over manually adjusted EPAP for treating these patients. This study compared 4% oxygen desaturation index (ODI4%) values during the use of an AutoEPAP algorithm versus manual EPAP titration with the intelligent volume-assured pressure support (iVAPS) algorithm.

METHODS

This prospective, single-blind, randomized, crossover study was conducted at six US sites. Patients with chronic respiratory failure (neuromuscular disease, chronic obstructive pulmonary disease, obesity hypoventilation and other aetiologies) and an apnoea-hypopnoea index of >5/h who were already established NIV users underwent a single night of NIV with the iVAPS manual EPAP and iVAPS AutoEPAP in the sleep laboratory in random order.

RESULTS

A total of 38 patients constituted the study population. Mean ODI4% was statistically non-inferior with AutoEPAP versus manual EPAP (P < 0.0001). There was no difference in the effect on ODI4% across respiratory failure subgroups. Ventilation parameters and gas exchange were similar with either NIV mode, indicating equally effective treatment of respiratory failure. Sleep parameters were improved during AutoEPAP versus manual EPAP.

CONCLUSION

A single night of NIV using the iVAPS with AutoEPAP algorithm was non-inferior to a single night of iVAPS with manual EPAP titration in patients with respiratory failure.

CLINICAL TRIAL REGISTRATION

NCT02683772 at clinicaltrials.gov.

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 6 h (mean reduction in PaCO₂ was 7 ± 7 mmHg in group 1 and 2 ± 5 mmHg in group 2, p = 0.025), and significantly greater reductions in PaCO₂ (18 ± 11 mmHg in group 1 and 9 ± 8 mmHg in group 2, p = 0.008) and plasma HCO₃ levels (from 32 to 30 mEq and from 35 to 35 mEq, p = 0.007) took place within first 4 days. 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.

New modes in non-invasive ventilation

Non-invasive ventilation is useful to treat some forms of respiratory failure. Hence, the number of patients receiving this treatment is steadily increasing. Considerable conceptual and technical progress has been made in the last years by manufacturers concerning this technique. This includes new features committed to improve its effectiveness as well as patient-ventilator interactions. The goal of this review is to deal with latest advances in ventilatory modes and features available for non-invasive ventilation. We present a comprehensive analysis of new modes of ventilator assistance committed to treat respiratory failure (hybrid modes) and central and complex sleep apnea (adaptive servo ventilation), and of new modes of triggering and cycling (neurally adjusted ventilatory assist). Technical aspects, modes of operation and settings of these new features as well as an exhaustive review of published data, their benefits and limits, and the potential place of these devices in clinical practice, are discussed.

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

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

Randomized trial of 'intelligent' autotitrating ventilation versus standard pressure support non-invasive ventilation: impact on adherence and physiological outcomes

BACKGROUND AND OBJECTIVE

Effective non-invasive ventilation (NIV) therapy is dependent on optimal ventilator settings to maximize clinical benefit and patient tolerance. Intelligent volume-assured pressure support (iVAPS) is a hybrid mode of servoventilation, providing constant automatic adjustment of pressure support (PS) to achieve a target ventilation determined by the patient's requirements. In a randomized crossover trial, we tested the hypothesis that iVAPS, with automated selection of ventilator settings, was non-inferior to standard PS ventilation, with settings determined by an experienced health-care professional, for controlling nocturnal hypoventilation in patients naive to NIV.

METHODS

Eighteen patients referred to a ventilator clinic with chronic obstructive or restrictive lung disease and newly diagnosed nocturnal hypoventilation (10 male, median (interquartile range): age 54(41-61) years, mean daytime PaO2 9.25(8.59-10.31) kPa, -PaCO2 6.38(5.93-6.65) kPa were randomized to iVAPS and standard PS. Polysomnography with transcutaneous CO2 monitoring was performed at baseline and 1 month after each treatment period. Nightly hours of therapy were recorded by the ventilator.

RESULTS

iVAPS delivered a lower median PS compared with standard PS (8.3(5.6-10.4) vs 10.0(9.0-11.4) cmH2 O; P = 0.001) for the same ventilatory outcome (mean overnight: SpO2 96(95-98) vs 96(93-97)%; P = 0.13 and PtcCO2 6.5(5.8-6.8) vs 6.2(5.8-6.9); P = 0.54). There was no difference in outcome between ventilator modes for spirometry, respiratory muscle strength, sleep quality, arousals or O2 desaturation index. Adherence was greater with iVAPS (5:40(4:42-6:49) vs 4:20(2:27-6:17) hh:mm/night; P = 0.004).

CONCLUSIONS

iVAPS servoventilation with automation of ventilation settings is as effective as PS ventilation initiated by a skilled health-care professional in controlling nocturnal hypoventilation and produced better overnight adherence in patients naive to NIV.

Minute ventilation during spontaneous breathing, high-intensity noninvasive positive pressure ventilation and intelligent volume assured pressure support in hypercapnic COPD

BACKGROUND

High-intensity noninvasive positive pressure ventilation (HI-NPPV) is an effective treatment option in patients with stable hypercapnic chronic obstructive pulmonary disease (COPD). However, the effect of HI-NPPV compared with spontaneous breathing (SB) on minute ventilation (MV) in patients receiving long-term treatment remains to be determined. This study compared MV during HI-NPPV and SB. In addition, the ability of intelligent volume assured pressure support (iVAPS) to increase MV to the same extent as HI-NPPV was determined.

METHODS

Daytime pneumotachographic measurements were performed during SB, HI-NPPV and iVAPS.

RESULTS

Twenty-seven stable hypercapnic COPD patients (mean FEV1 34 ± 15% predicted) who had been treated with HI-NPPV for a median of 22 months (interquartile range 8.5-84 months) were enrolled. Mean MV was 9.5 ± 1.7 L/min during SB and 12.1 ± 2.8 L/min during HI-NPPV, an increase of 2.5 L/min (95% CI [1.5-3.6] p < 0.001), or 26%. MV during iVAPS was 11.7 ± 3.6 L/min, an increase of 1.8 L/min (95%CI [0.7-3.0], p = 0.003) compared with SB. There was no difference in MV between HI-NPPV and iVAPS (p = 0.25).

CONCLUSION

Long-term HI-NPPV increased MV by an average of 26% compared with SB in stable hypercapnic COPD patients. A similar increase in MV was observed during use of iVAPS.

Noninvasive mechanical ventilation with average volume assured pressure support (AVAPS) in patients with chronic obstructive pulmonary disease and hypercapnic encephalopathy

BACKGROUND

Non-invasive mechanical ventilation (NIV) in patients with acute respiratory failure has been traditionally determined based on clinical assessment 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 adjusts to a patient's needs. Our study assessed the use of BiPAP S/T with AVAPS in patients with chronic obstructive pulmonary disease (COPD) and hypercapnic encephalopathy as compared to BiPAP S/T alone, upon immediate arrival in the Emergency-ICU.

METHODS

We carried out a prospective interventional match-controlled study in Guayaquil, Ecuador. A total of 22 patients were analyzed. Eleven with COPD exacerbations and hypercapnic encephalopathy with a Glasgow Coma Scale (GCS) <10 and a pH of 7.25-7.35 were assigned to receive NIV via BiPAP S/T with AVAPS. Eleven patients were selected as paired controls for the initial group by physicians who were unfamiliar with our study, and these patients were administered BiPAP S/T. Arterial blood gases, GCS, vital signs, and ventilatory parameters were then measured and compared between the two groups.

RESULTS

We observed statistically significant differences in favor of the BiPAP S/T + AVAPS group in GCS (P = .00001), pCO(2) (P = .03) and maximum inspiratory positive airway pressure (IPAP) (P = .005), among others. However, no significant differences in terms of length of stay or days on NIV were observed.

CONCLUSIONS

BiPAP S/T with AVAPS facilitates rapid recovery of consciousness when compared to traditional BiPAP S/T in patients with chronic obstructive pulmonary disease and hypercapnic encephalopathy.

TRIAL REGISTRATION

Current Controlled Trials application ref is ISRCTN05135218.

Monitoring Patient/Ventilator Interactions: Manufacturer's Perspective

The introduction of reduced and more powerful electronics has allowed the transition of medical equipment such as respiratory support devices from the hospital to the patient’s home environment. Even if this move could be beneficial for the patient, the clinician ends up in a delicate situation where little or no direct supervision is possible on the delivered treatment.

Progress in technologies led to an improved handling of patient-device interaction: manufacturers are promoting new or improved ventilation modes or cycling techniques for better patient-ventilator coupling. Even though these ventilation modes have become more responsive to patient efforts, adversely they might lead to events such as false triggering, autotriggering, delayed triggering.

In addition, manufacturers are developing tools to enhance the follow-up, remotely or offline, of the treatment by using embedded memory in the respiratory devices. This logging might be beneficial for the caregiver to review and document the treatment and tune the settings to the patient’s need and comfort. Also, remote telemedicine has been raised as a potential solution for many years without yet overall acceptance due to legal, technical and ethical problems.

Benefits of new technologies in respiratory support devices give the technical foundation for the transition from hospital to home and reducing patient/ventilator asynchronies. Healthcare infrastructure has to follow this trend in terms of cost savings versus hospital stays.

[Field 5. Safety practices procedures for mechanical ventilation. French-speaking Society of Intensive Care. French Society of Anesthesia and Resuscitation]

Invasive or endotracheal mechanical ventilation can lead to numerous complications likely to burden morbidity and mortality of patients in the intensive care unit. Various safety practices for mechanical ventilation may involve intubation, the mechanical ventilation period, weaning and extubation, the use of tracheostomy as well as non-invasive ventilation. The main objective of safety practices described in this chapter is to prevent or avoid the main risks due to invasive mechanical ventilation.