• N C Singh, N Kissoon, T Frewen, and N Tiffin.
• Departments of Pediatrics, Children's Hospital of Western Ontario, London, Canada.
• Clin Intensive Care. 1991 Jan 1;2(6):345-50.

ObjectiveTo study the influence of varying outer suction catheter (SC) diameter (OD) to inner endotracheal tube (ETT) diameter (ID) and suction pressures (SP) on heart rate (HR), respiratory rate (RR), mean arterial pressure (MAP), arterial oxygen saturation (SaO 2) and intracranial pressure (ICP) during ETT and oral suctioning. An additional aim was to define an optimal suction catheter size that would prove easy to introduce and be rapidly effective in clearing secretions with the least physiological alteration.DesignProspective study.SettingPaediatric intensive care unit.PatientsVentilated paediatric patients.InterventionPatients had ETT suctioning performed in a random fashion using suction catheters with SC outer diameter to inner ETT diameter of approximately 0.4, 0.7 and 0.9 using varying pressures (80, 100, 120 mmHg). Using the medium size suction catheter (OD/ID = 0.7) at 100 mmHg of suction pressure, oral suctioning was compared to ETT suctioning.Measurements And Main ResultsSeventeen patients were studied (age 6.5 + 5 months). All suction catheters at varying pressures resulted in similar transient alterations in HR, RR, MAP, SaO 2 and ICP following ETT suctioning. Significant changes were seen in SaO 2, HR and ICP, irrespective of the catheter diameter or suction pressure. Oral suctioning resulted in similar trends and magnitude of changes as for ETT suctioning in MAP, RR, HR, and ICP, but less change occurred in the SaO 2 (p less than 0.05). The catheters with OD/ID of 0.7 were easiest to introduce and most effective in clearing secretions.ConclusionOur study suggests that: 1. Tracheal toilet using variations in OD/ID ratios and SP within limits tested resulted in similar significant adverse changes in HR, ICP and SaO 2 and similar trends in RR and MAP. 2. Based on the ease of introduction and the effectiveness of clearing secretions, a medium SC (OD/ID = 0.7) is most appropriate for infants and children. 3. Oral suctioning also results in adverse physiological changes, therefore similar precautions to those taken during tracheal suctioning should be followed for oral suctioning.

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