Physiological Consequences of Low and High Flow Endotracheal Suctioning Devices in Intubated Preterm and Term Infants

Respiratory failure in neonates frequently requires mechanical ventilation through an endotracheal tube (ETT). The presence of an ETT inhibits the infant's intrinsic ability to clear endogenous lung secretions effectively with compromised glottic closure and impaired muccociliary function, and thus regular supportive suctioning of the ETT is essential. The benefits of patent airway are evident, but adverse effects may also result from suctioning which are especially deleterious in extremely preterm infants with immature pulmonary and systemic hemodynamic function. These adverse effects include transient hypoxemia and oxygen desaturation, vasovagal reactions, altered central and cerebral hemodynamics, atelectasis, pneumothorax, and mucosal damage. The cardiorespiratory instability during ETT suctioning is partially attributed to alveolar decruitment and loss of lung volume from disconnecting the ETT from the ventilator circuit and negative suction pressure. Maintenance of lung volume is essential to optimize gas exchange and prevent ventilator induced lung injury. The magnitude of lung volume loss is related to catheter size and applied suctioning pressure and flow, highlighting the complexity of interaction between suction technique, lung mechanics and disease state. In accordance with industry standard codes, a high flow rate is essential to ensure the rapid removal of fluid and secretions from the desired site and the standard conventional wall (SCW) suction outlets provide a minimum flow of approximately 85 liters per minute. Such high flows can lead to endotracheal suctioning-induced alveolar decruitment that may of significant clinical relevance. Recently, a low flow technology suction device EXSALTA (ED) for clearing ETT secretions in patients on ventilators has been approved by FDA. The device uses peristaltic action to move fluids from the patient to a collection canister at a fixed flow rate of 1.4 L/min and eliminates the uncontrolled flow of air from the patient's lungs. The user selects a desired pressure level that is independent of the flow rate, a feature unavailable with SCW wall suction equipment used at patient's bedside. This exceptional microprocessor-controlled tabletop suction device, available at any suction setting, reduces risk of negative pressures in the lungs to help prevent alveolar collapse and hypoxia associated with standard suctioning techniques. This study will examine the hypothesis that there will be significantly lower variations in heart rate (HR), oxygen saturation (SpO2), cerebral oxygenation (C-rSO2), and cerebral fractional oxygen extraction (c-FOE) with ED compared to SCW suction system during open or closed ETT suctioning. To test this hypothesis, the physiological consequences of two ETT suctioning systems in preterm and term infants will be evaluated using the following aims:

AIM 1. To compare the variations in HR (bpm), SpO2 (%), C-rSO2 (%), C-FOE (%) between ED and SCW suctioning systems during routine standard care open and closed ETT suctioning.

AIM II. To compare the incidence (episodes) of cardiorespiratory disturbances, i.e. bradycardia (HR<80 bpm) and/or hemoglobin oxygen desaturation (SpO2) < 80% for more than 10s during suctioning with ED and SCW suctioning system during routine standard care open and closed ETT suctioning.