Recent Advances in Pediatric Ventilatory Assistance

The Physiological Basis of High-Frequency Oscillatory Ventilation and Current Evidence in Adults and Children: A Narrative Review

High-frequency oscillatory ventilation (HFOV) is a type of invasive mechanical ventilation that employs supra-physiologic respiratory rates and low tidal volumes (V_T) that approximate the anatomic deadspace. During HFOV, mean airway pressure is set and gas is then displaced towards and away from the patient through a piston. Carbon dioxide (CO₂) is cleared based on the power (amplitude) setting and frequency, with lower frequencies resulting in higher V_T and CO₂ clearance. Airway pressure amplitude is significantly attenuated throughout the respiratory system and mechanical strain and stress on the alveoli are theoretically minimized. HFOV has been purported as a form of lung protective ventilation that minimizes volutrauma, atelectrauma, and biotrauma. Following two large randomized controlled trials showing no benefit and harm, respectively, HFOV has largely been abandoned in adults with ARDS. A multi-center clinical trial in children is ongoing. This article aims to review the physiologic rationale for the use of HFOV in patients with acute respiratory failure, summarize relevant bench and animal models, and discuss the potential use of HFOV as a primary and rescue mode in adults and children with severe respiratory failure.

Update on ventilation management in the Pediatric Intensive Care Unit

Studies have shown that up to 63% of pediatric intensive care unit patients admitted with acute respiratory or cardiorespiratory illness require mechanical ventilation. Mechanical ventilator support can be divided into three phases: initiation, escalation, and resolution. Noninvasive ventilation is typical during the initiation phase in the management of acute pediatric respiratory failure. The major advancements in the use of noninvasive ventilation involve the emergence of high-flow nasal cannula and how widespread the use of high-flow nasal cannula has become in pediatric critical care practice. When high-flow nasal cannula fails, escalation to continuous positive airway pressure or bi-level positive airway pressure is the next step in respiratory care progression. Careful clinical assessment is necessary to avoid delayed escalation between forms of noninvasive support or escalation to intubation and invasive mechanical ventilation. Advancements in conventional mechanical ventilation are centered on optimizing ventilator settings and customizing monitoring with the overarching goal to reduce complications of mechanical ventilation, such as ventilator-induced lung injury. New mechanical ventilator strategies integrating esophageal pressure monitoring, volumetric capnography, and neurally adjusted ventilator assist help to optimize conventional ventilator support. Nonconventional modes of ventilation in the intensive care unit are high-frequency modes and airway pressure release ventilation. Extracorporeal pulmonary support via extracorporeal membrane oxygenation or paracorporeal lung assist devices provides rescue options when conventional and nonconventional methods fail. During resolution of a course of mechanical ventilator support, reliable weaning strategies and extubation readiness testing are lacking in pediatric critical care. Further, timing of tracheostomy, risk reduction in ventilator-induced lung injury, and decreased sedation requirements in pediatric patients requiring mechanical ventilation in the pediatric intensive care unit are areas of ongoing research.

Health Technology Assessment of Intensive Care Ventilators for Pediatric Patients

This paper is aimed at addressing all the critical aspects linked to the implementation of intensive care ventilators in a pediatric setting, highlighting the most relevant technical features and describing the methodology to conduct health technology assessment (HTA) for supporting the decision-making process. Four ventilator models were included in the assessment process. A decision-making support tool (DoHTA method) was applied. Twenty-eight Key Performance Indicators (KPIs) were identified, defining the safety, clinical effectiveness, organizational, technical, and economic aspects. The Performance scores of each ventilator have been measured with respect to KPIs integrated with the total cost of ownership analysis, leading to a final rank of the four possible technological solutions. The final technologies' performance scores reflected a deliver valued, contextualized, and shared outputs, detecting the most performant technological solution for the specific hospital context. HTA results had informed and supported the pediatric hospital decision-making process. This study, critically identifying the pros and cons of innovative features of ventilators and the evaluation criteria and aspects to be taken into account during HTA, can be considered as a valuable proof of evidence as well as a reliable and transferable method for conducting decision-making processes in a hospital context.

Neurally Adjusted Ventilator Assist in Infants With Acute Respiratory Failure: A Literature Scoping Review

OBJECTIVES

To map the evidence for neurally adjusted ventilatory assist strategies, outcome measures, and sedation practices in infants less than 12 months with acute respiratory failure using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews guidance.

DATA SOURCES

CINAHL, MEDLINE, COCHRANE, JBI, EMBASE, PsycINFO, Google scholar, BNI, AMED. Trial registers included the following: ClinicalTrials.gov, European Union clinical trials register, International Standardized Randomized Controlled Trial Number register. Also included were Ethos, Grey literature, Google, dissertation abstracts, EMBASE conference proceedings.

STUDY SELECTION

Abstracts were screened followed by review of full text. Articles incorporating a heterogeneous population of both infants and older children were assessed, and where possible, data for infants were extracted. Fifteen articles were included. Ten articles were primary research: randomized controlled trial (n = 3), cohort studies (n = 4), retrospective data analysis (n = 2), case series (n = 1). Other articles are expert opinion (n = 2), neurally adjusted ventilatory assist updates (n = 1), and a literature review (n = 2). Three studies included exclusively infants. We also included 12 studies reporting jointly on infants and children.

DATA EXTRACTION

A standardized data extraction tool was used.

DATA SYNTHESIS

Key findings were that evidence related to neurally adjusted ventilatory assist ventilation strategies in infants and related to specific primary conditions is limited. The setting of neurally adjusted ventilatory assist level is not consistent, and how to optimize this mode of ventilation was not documented. Outcome measures varied considerably, most studies focused on improvements in respiratory and physiological variables. Sedation use is variable with regard to medication type and dose. There is an indication that less sedation is required in patients receiving neurally adjusted ventilatory assist, but no conclusive evidence to support this.

CONCLUSIONS

This review highlights a lack of standardized strategies for neurally adjusted ventilatory assist ventilation and sedation practices among infants with acute respiratory failure. Studies were limited by small sample sizes and a lack of focus on specific patient groups. Robust studies are needed to provide evidence-based clinical recommendations for the use of neurally adjusted ventilatory assist in infants with acute respiratory failure.

Extubation in the pediatric intensive care unit: predictive methods. An integrative literature review

For extubation in pediatric patients, the evaluation of readiness is strongly recommended. However, a device or practice that is superior to clinical judgment has not yet been accurately determined. Thus, it is important to conduct a review on the techniques of choice in clinical practice to predict extubation failure in pediatric patients. Based on a search in the PubMed®, Biblioteca Virtual em Saúde, Cochrane Library and Scopus databases, we conducted a survey of the predictive variables of extubation failure most commonly used in clinical practice in pediatric patients. Of the eight predictors described, the three most commonly used were the spontaneous breathing test, the rapid shallow breathing index and maximum inspiratory pressure. Although the disparity of the data presented in the studies prevented statistical treatment, it was still possible to describe and analyze the performance of these tests.

Use of esophageal balloon manometry in the management of pediatric acute respiratory distress syndrome

There is paucity of literature regarding the use of esophageal balloon manometry in the management of Pediatric Acute Respiratory Distress Syndrome. We describe our first ever experience of successful usage of esophageal balloon pressure manometry in a child with acute respiratory distress syndrome. This is a six-year-old girl who presented with shortness of breath and fever and was found to be in severe acute respiratory distress syndrome due to septic shock secondary to group A streptococcus. The patient was managed using an esophageal balloon manometry for positive end-expiratory pressure titration. She was liberated from invasive mechanical ventilation on day 7 of hospital course. Esophageal balloon manometry guided positive end-expiratory pressure for 103 out of 155 hours of ventilation with no obvious sequelae. Our case shows the feasibility of transpulmonary pressure measurements in pediatric patients. This practice may be useful to optimize management in pediatric acute respiratory distress syndrome to improve outcomes.