Expiratory Ventilation Assistance Research Articles

Ventilation through small‐bore airways in children by implementing active expiration

Management of narrowed airways can be challenging, especially in the smallest patients. This educational review focusses on active expiration through small‐bore airways with the Ventrain (Ventinova Medical, Eindhoven, The Netherlands). Manual ventilation with the Ventrain establishes inspiratory and expiratory flow control: By setting an appropriate flow, the volume of gas insufflated over time can be controlled and expiration through a small‐bore airway is expedited by jet‐flow generated suction, coined “expiratory ventilation assistance” (EVA). This overcomes the inherent risks of emergency jet ventilation especially in pediatric airway emergencies. Active expiration by EVA has been clinically introduced to turn a “straw in the airway” into a lifesaver allowing not only for quick and reliable reoxygenation but also adequate ventilation. As well as managing airway emergencies, ventilating through small‐bore airways by applying EVA implements new options for pediatric airway management in elective interventional procedures. Safe application of EVA demands a thorough understanding of the required equipment, the principle and function of the Ventrain, technical prerequisites, clinical safety measures, and, most importantly, appropriate training.

Flow-controlled ventilation during ear, nose and throat surgery: A prospective observational study.

Flow-controlled ventilation (FCV) is a new mechanical ventilation mode that maintains constant flow during inspiration and expiration with standard tidal volumes via cuffed narrow-bore endotracheal tubes. Originating in manually operated 'expiratory ventilation assistance', FCV extends this technique by automatic control of airway flow, monitoring of intratracheal pressure and control of peak inspiratory pressure and end-expiratory pressure. FCV has not yet been described in a clinical study. The aim of this study was to provide an initial assessment of FCV in mechanically ventilated patients undergoing ear, nose and throat surgery and evaluate its potential for future use. An observational study. Two German academic medical centres from 24 November 2017 to 09 January 2018. Consecutive patients (≥ 18 years) scheduled for elective ear, nose and throat surgery. Exclusion criteria were planned laser surgery, intended fibreoptic awake intubation, emergency procedures, increased risk of aspiration, American Society of Anesthesiologists (ASA) physical status more than III and chronic obstructive pulmonary disease classified as GOLD stage more than II. Peri-operative use of FCV provided by a new type of ventilator (Evone) via a narrow-bore endotracheal tube (Tritube). Minute volume, respiratory rate, intratidal tracheal pressure amplitude (Δp) and end-tidal CO2 (PetCO2) were recorded every 5 min. All adverse events were noted. Data are presented as median [IQR]. Sixteen patients provided 15 evaluable data sets. A minute volume of 5.0 [4.4 to 6.4] l min and a respiratory rate of 9 [8 to 11] min generated a PetCO2 of 4.9 [4.8 to 5.0] kPa. Δp was 10 [9 to 12] cmH2O. Five adverse events were recorded: a tube obstruction due to airway secretions and four tube dislocations (two attributed to coughing, two not study-related). FCV achieves adequate PetCO2 levels with minute volume and Δp in the normal range. Tritube's high flow resistance may increase the likelihood of tube dislocations if the patient coughs. Although further evaluation is necessary, FCV provides a new option for short-term mechanical ventilation. The successful operation of FCV with narrow-bore tubes contributes to the armamentarium for airway management. DRKS00013312.

Automated expiratory ventilation assistance through a small endotracheal tube can improve venous return and cardiac output

BackgroundPositive pressure ventilation can decrease venous return and cardiac output. It is not known if expiratory ventilation assistance (EVA) through a small endotracheal tube can improve venous return and cardiac output.ResultsIn a porcine model, switching from conventional positive pressure ventilation to (EVA) with − 8 cmH20 expiratory pressure increased the venous return and cardiac output. The stroke volume increased by 27% when the subjects were switched from conventional ventilation to EVA [53.8 ± 7.7 (SD) vs. 68.1 ± 7.7 ml, p = 0.003]. After hemorrhage, subjects treated with EVA had higher median cardiac output, higher mean systemic arterial pressure, and lower central venous pressure at 40 and 60 min when compared with subjects treated with conventional ventilation with PEEP 0 cmH20. The median cardiac output was 41% higher in the EVA group than the control group at 60 min [2.70 vs. 1.59 L/min, p = 0.029].ConclusionEVA through a small endotracheal tube increased venous return, cardiac output, and mean arterial pressure compared with conventional positive pressure ventilation. The effects were most significant during hypovolemia from hemorrhage. EVA provided less effective ventilation than conventional positive pressure ventilation.

Improved lung recruitment and oxygenation during mandatory ventilation with a new expiratory ventilation assistance device: A controlled interventional trial in healthy pigs.

In contrast to conventional mandatory ventilation, a new ventilation mode, expiratory ventilation assistance (EVA), linearises the expiratory tracheal pressure decline. We hypothesised that due to a recruiting effect, linearised expiration oxygenates better than volume controlled ventilation (VCV). We compared the EVA with VCV mode with regard to gas exchange, ventilation volumes and pressures and lung aeration in a model of peri-operative mandatory ventilation in healthy pigs. Controlled interventional trial. Animal operating facility at a university medical centre. A total of 16 German Landrace hybrid pigs. The lungs of anaesthetised pigs were ventilated with the EVA mode (n=9) or VCV (control, n=7) for 5 h with positive end-expiratory pressure of 5 cmH2O and tidal volume of 8 ml kg. The respiratory rate was adjusted for a target end-tidal CO2 of 4.7 to 6 kPa. Tracheal pressure, minute volume and arterial blood gases were recorded repeatedly. Computed thoracic tomography was performed to quantify the percentages of normally and poorly aerated lung tissue. Two animals in the EVA group were excluded due to unstable ventilation (n=1) or unstable FiO2 delivery (n=1). Mean tracheal pressure and PaO2 were higher in the EVA group compared with control (mean tracheal pressure: 11.6 ± 0.4 versus 9.0 ± 0.3 cmH2O, P < 0.001 and PaO2: 19.2 ± 0.7 versus 17.5 ± 0.4 kPa, P = 0.002) with comparable peak inspiratory tracheal pressure (18.3 ± 0.9 versus 18.0 ± 1.2 cmH2O, P > 0.99). Minute volume was lower in the EVA group compared with control (5.5 ± 0.2 versus 7.0 ± 1.0 l min, P = 0.02) with normoventilation in both groups (PaCO2 5.4 ± 0.3 versus 5.5 ± 0.3 kPa, P > 0.99). In the EVA group, the percentage of normally aerated lung tissue was higher (81.0 ± 3.6 versus 75.8 ± 3.0%, P = 0.017) and of poorly aerated lung tissue lower (9.5 ± 3.3 versus 15.7 ± 3.5%, P = 0.002) compared with control. EVA ventilation improves lung aeration via elevated mean tracheal pressure and consequently improves arterial oxygenation at unaltered positive end-expiratory pressure (PEEP) and peak inspiratory pressure (PIP). These findings suggest the EVA mode is a new approach for protective lung ventilation.

Transtracheal ventilation with a novel ejector-based device (Ventrain) in open, partly obstructed, or totally closed upper airways in pigs

Transtracheal access and subsequent jet ventilation are among the last options in a 'cannot intubate-cannot oxygenate' scenario. These interventions may lead to hypercapnia, barotrauma, and haemodynamic failure in the event of an obstructed upper airway. The aim of the present study was to evaluate the efficacy and the haemodynamic effects of the Ventrain, a manually operated ventilation device that provides expiratory ventilation assistance. Transtracheal ventilation was carried out with the Ventrain in different airway scenarios in live pigs, and its performance was compared with a conventional jet ventilator. Pigs with open, partly obstructed, or completely closed upper airways were transtracheally ventilated either with the Ventrain or by conventional jet ventilation. Airway pressures, haemodynamic parameters, and blood gases obtained in the different settings were compared. Mean (SD) alveolar minute ventilation as reflected by arterial partial pressure of CO2 was superior with the Ventrain in partly obstructed airways after 6 min in comparison with traditional manual jet ventilation [4.7 (0.19) compared with 7.1 (0.37) kPa], and this was also the case in all simulated airway conditions. At the same time, peak airway pressures were significantly lower and haemodynamic parameters were altered to a lesser extent with the Ventrain. The results of this study suggest that the Ventrain device can ensure sufficient oxygenation and ventilation through a small-bore transtracheal catheter when the airway is open, partly obstructed, or completely closed. Minute ventilation and avoidance of high airway pressures were superior in comparison with traditional hand-triggered jet ventilation, particularly in the event of complete upper airway obstruction.

Pulmonary effects of expiratory-assisted small-lumen ventilation during upper airway obstruction in pigs.

Novel devices for small-lumen ventilation may enable effective inspiration and expiratory ventilation assistance despite airway obstruction. In this study, we investigated a porcine model of complete upper airway obstruction. After ethical approval, we randomly assigned 13 anaesthetised pigs either to small-lumen ventilation following airway obstruction (n=8) for 30min, or to volume-controlled ventilation (sham setting, n=5). Small-lumen ventilation enabled adequate gas exchange over 30 min. One animal died as a result of a tension pneumothorax in this setting. Redistribution of ventilation from dorsal to central compartments and significant impairment of the distribution of ventilation/perfusion occurred. Histopathology demonstrated considerable lung injury, predominantly through differences in the dorsal dependent lung regions. Small-lumen ventilation maintained adequate gas exchange in a porcine airway obstruction model. The use of this technique for 30 min by inexperienced clinicians was associated with considerable end-expiratory collapse leading to lung injury, and may also carry the risk of severe injury.

Rescue ventilation through a small-bore transtracheal cannula in severe hypoxic pigs using expiratory ventilation assistance.

BACKGROUND:Suction-generated expiratory ventilation assistance (EVA) has been proposed as a way to facilitate bidirectional ventilation through a small-bore transtracheal cannula (TC). In this study, we investigated the efficiency of ventilation with EVA for restoring oxygenation and ventilation in a pig model of acute hypoxia.METHODS:Six pigs (61–76 kg) were anesthetized and ventilated (intermittent positive pressure ventilation) via a cuffed endotracheal tube (ETT). Monitoring lines were placed, and a 75-mm long, 2-mm inner diameter TC was inserted. After the baseline recordings, the ventilator was disconnected. After 2 minutes of apnea, reoxygenation with EVA was initiated through the TC and continued for 15 minutes with the ETT occluded. In the second part of the study, the experiment was repeated with the ETT either partially obstructed or left open. Airway pressures and hemodynamic data were recorded, and arterial blood gases were measured. Descriptive statistical analysis was performed.RESULTS:With a completely or partially obstructed upper airway, ventilation with EVA restored oxygenation to baseline levels in all animals within 20 seconds. In a completely obstructed airway, Paco2 remained stable for 15 minutes. At lesser degrees of airway obstruction, the time to reoxygenation was delayed. Efficacy probably was limited when the airway was completely unobstructed, with 2 of 6 animals having a Pao2 <85 mm Hg even after 15 minutes of ventilation with EVA and a mean Paco2 increased up to 90 mm Hg.CONCLUSIONS:In severe hypoxic pigs, ventilation with EVA restored oxygenation quickly in case of a completely or partially obstructed upper airway. Reoxygenation and ventilation were less efficient when the upper airway was completely unobstructed.

Optimizing ventilation through a cuffed narrow bore catheter (CNBC) using expiratory ventilation assistance (EVA): an animal study

Optimizing ventilation through a cuffed narrow bore catheter (CNBC) using expiratory ventilation assistance (EVA): an animal study

Adequate minute volume ventilation through a 100 cm long, 3 mm inner diameter airway exchange catheter by expiratory ventilation assistance (EVA)

Adequate minute volume ventilation through a 100 cm long, 3 mm inner diameter airway exchange catheter by expiratory ventilation assistance (EVA)

Ventilation through a small-bore catheter: optimizing expiratory ventilation assistance

BackgroundEmergency ventilation through a small-bore transtracheal catheter can be lifesaving in a ‘cannot intubate, cannot ventilate’ situation. Ejectors, capable of creating suction by the Bernoulli principle, have been proposed to facilitate expiration through small-bore catheters. In this bench study, we compared a novel, purpose-built ventilation ejector (DE 5) with a previously proposed, modified industrial ejector (SBP 07). MethodsThe generated insufflation pressures, suction pressures in static and dynamic situations, and also suction capacities and entrainment ratios of the SBP 07 and the DE 5 were determined. The DE 5 was also tested in a lung simulator with a simulated complete upper airway obstruction. Inspiratory and expiratory times through a transtracheal catheter were measured at various flow rates and achievable minute volumes were calculated. ResultsIn a static situation, the SBP 07 showed a more negative pressure build-up compared with the DE 5. However, in a dynamic situation, the DE 5 generated a more negative pressure, resulting in a higher suction capacity. Employment of the DE 5 at a flow rate of 18 litre min−1 allowed a minute volume through the transtracheal catheter of up to 8.27 litre min−1 at a compliance of 100 ml cm H2O−1. The efficiency of the DE 5 depended on the flow rate of the driving gas and the compliance of the lung simulator. ConclusionIn laboratory tests, the DE 5 is an optimized ventilation ejector suitable for applying expiratory ventilation assistance. Further research may confirm the clinical applicability as a portable emergency ventilator for use with small-bore catheters.

Achieving an adequate minute volume through a 2 mm transtracheal catheter in simulated upper airway obstruction using a modified industrial ejector

Needle cricothyrotomy and subsequent transtracheal jet ventilation (TTJV) is one of the last options to restore oxygenation while managing an airway emergency. However, in cases of complete upper airway obstruction, conventional TTJV is ineffective and dangerous. We transformed a small, industrial ejector into a simple, manual ventilator providing expiratory ventilation assistance (EVA). An ejector pump was modified to allow both insufflation of oxygen and jet-assisted expiration through an attached 75 mm long transtracheal catheter (TTC) with an inner diameter (ID) of 2 mm by alternately occluding and releasing the gas outlet of the ejector pump. In a lung simulator, the modified ejector pump was tested at different compliances and resistances. Inspiration and expiration times were measured and achievable minute volumes (MVs) were calculated to determine the effect of EVA. The modified ejector pump shortened the expiration time and an MV up to 6.6 litre min(-1) could be achieved through a 2 mm ID TTC in a simulated obstructed airway. The principle of ejector-based EVA seems promising and deserves further evaluation.

Comparison of esophageal and pleural pressures in the anesthetized dog.

ArticleComparison of esophageal and pleural pressures in the anesthetized dog.D J Gillespie, Y L Lai, and R E HyattD J Gillespie, Y L Lai, and R E HyattPublished Online:01 Nov 1973https://doi.org/10.1152/jappl.1973.35.5.709MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByThoracic gas compression during forced expiration is greater in men than womenPhysiological Reports, Vol. 8, No. 6Automated expiratory ventilation assistance through a small endotracheal tube can improve venous return and cardiac output9 January 2019 | Intensive Care Medicine Experimental, Vol. 7, No. 1Reliability of transpulmonary pressure–time curve profile to identify tidal recruitment/hyperinflation in experimental unilateral pleural effusion20 July 2016 | Journal of Clinical Monitoring and Computing, Vol. 31, No. 4Transpulmonary Pressure Meaning: Babel or Conceptual Evolution?American Journal of Respiratory and Critical Care Medicine, Vol. 195, No. 10Correcting the dynamic response of a commercial esophageal balloon-catheterTroy J. Cross, Kenneth C. Beck, and Bruce D. Johnson9 August 2016 | Journal of Applied Physiology, Vol. 121, No. 2Response characteristics of esophageal balloon catheters handmade using latex and nonlatex materials15 June 2015 | Physiological Reports, Vol. 3, No. 6Comparative Ventilation of the Normal LungThe assessment of transpulmonary pressure in mechanically ventilated ARDS patients12 August 2014 | Intensive Care Medicine, Vol. 40, No. 11Compressive Forces and Computed Tomography–derived Positive End-expiratory Pressure in Acute Respiratory Distress SyndromeAnesthesiology, Vol. 121, No. 3Pleural Effusion in Patients With Acute Lung InjuryCritical Care Medicine, Vol. 41, No. 4Propofol Attenuates the Decrease of Dynamic Compliance and Water Content in the Lung by Decreasing Oxidative Radicals Released from the Reperfused LiverAnesthesia & Analgesia, Vol. 107, No. 4Lung Stress and Strain during Mechanical Ventilation for Acute Respiratory Distress SyndromeAmerican Journal of Respiratory and Critical Care Medicine, Vol. 178, No. 4Telemetric Recording of Intrapleural PressureJournal of Surgical Research, Vol. 138, No. 1Novel aspects of pulmonary mechanics in intensive careBritish Journal of Anaesthesia, Vol. 91, No. 1A novel method for chronic measurement of respiratory function in the conscious monkeyJournal of Pharmacological and Toxicological Methods, Vol. 46, No. 1Recruitment and Derecruitment During Acute Respiratory FailureAmerican Journal of Respiratory and Critical Care Medicine, Vol. 164, No. 1Lung and Chest Wall Mechanics in Anesthetized ChildrenAmerican Journal of Respiratory and Critical Care Medicine, Vol. 162, No. 2A novel method for chronic measurement of pleural pressure in conscious ratsJournal of Pharmacological and Toxicological Methods, Vol. 39, No. 3Assessment of Pulmonary Function and the Effects of Inhaled Toxicants12 July 2013Was it just our problem, or yours too? errors in body plethysmography, in infants, children, and adultsPediatric Pulmonology, Vol. 11, No. 4Mechanical Heart-Lung Interaction in the Adult Respiratory Distress SyndromeClinics in Chest Medicine, Vol. 11, No. 4Effects of Mechanical Ventilation on Right and Left Ventricular FunctionClinics in Chest Medicine, Vol. 9, No. 1A critical assessment of pulmonary function testing in exercising poniesVeterinary Research Communications, Vol. 12, No. 1Ventilation: Total, Alveolar, and Dead Space1 January 2011Effects of intravenous atropine on static P-V curves of the lung in normal manRespiration Physiology, Vol. 70, No. 2Drug-Induced Effects on Reticular Groove Reflex, Eructation and RuminationEffects of intravenous atropine on static P-V curves of the lung in normal manRespiration Physiology, Vol. 70, No. 1Tests of Mechanical Function1 January 2011Methods of study of airway smooth muscle and its physiologyPharmacology & Therapeutics, Vol. 7, No. 2Physiologic Effects of the Position of the Body in Experimental Unilateral EmphysemaChest, Vol. 74, No. 1 More from this issue > Volume 35Issue 5November 1973Pages 709-13 https://doi.org/10.1152/jappl.1973.35.5.709PubMed4770355History Published online 1 November 1973 Published in print 1 November 1973 Metrics