CHEST RADIOGRAPH

The Chest Radiograph: Effects of CVP Line, Trauma and Intervention

Chapter 1: Intrduction

Background of the study

Central Venous Pressure (CVP) lines are frequently inserted in critically ill infants and children for hemodynamic monitoring, delivery of intravenous fluids and medications, blood products, Total Parenteral Nutrition (TPN), and fat emulsion. They may also be used for drawing blood samples. Hemodynamic monitoring of central venous pressure reflects intravascular volume status and RV(Right Ventricular) function. Normal CVP values are 1- 7 Millimeters of Mercury (mmHg) in children. (Brown, 2009: 532) Low CVP measurements indicate hypovolemia. High CVP measurements indicate hypervolemia or elevated RV end-diastolic pressure. Pulmonary disease and Positive End-Expiratory Pressure (PEEPs) greater than 5 can result in false high CVP readings. The CVP line should be zero/calibrated every 12 hours. Also zero/calibrate when there is a change in caregiver, after changing tubing, or if readings are questionable. The yellow squeeze flush transducer will be used for transducing CVP lines. It will be primed with a solution of Normal Saline (NS) and 1 unit of heparin/ml. The transducer should be in the child's bed at the phlebostatic axis. Medications, TPN and intralipids can be Y'd into the line at the distal stopcock. In a multilumen line, vasoactive drips should be placed in the smallest lumen. Avoid infusing other solutions with vasoactive infusions if possible. To obtain an accurate CVP reading, turn off all stopcocks to fluids before reading measurement. The physician should be notified if the CVP line has no blood return or if a change in waveform is noted, which may indicate malposition of the catheter tip. (Homick, 2005: 1150-54)

Three hundred and seventy four random patients admitted to the postoperative Intensive Care Unit (lCU) underwent postoperative clinical positioning of Endotracheal Tube(ET), nasogastric tube, central venous catheter and laboratory Arterial Blood Gas (ABG) assessment. Chest roentgenography was done for all the admitted patients and the findings reviewed. Thirteen (3.47%) patients required intervention because of abnormalities detected on chest roentgenography. None of the pathologic conditions detected was life threatening. Chest roentgenography on admission to the cardiovascular ICU should be done only if the smgery has been performed for cardiac trauma, re-exploration, and also ifclinical and laboratory assessment indicate the possibility ofunderlying pathologic condi tions that can only be confirmed by chest roentgenography. (Mortensen, 2007: 1118-2)

Problem Statement

For many years, it has been routine practice to carry out chest radiography in many institutions after heart operations. However, doubts have been expressed concerning the need for this examination except when the medical history, clinical examination and laboratory data suggests some intrathoracic pathology. (Hamilton, 2006b: 59-65) Since cardiac operation done via median sternotomy facilitates inspection of the mediastinum and allows for the assessment ofllmg movement, it has been suggested that routine postoperative chest roentgenography may be omitted. The doubtful clinical value of immediate postoperative chest roentgenography prompted us to study whether it is really necessary to continue the practice of performing chest roentgenography on every patient after cardiac surgery. The goal is being to know the presence of underlying pathology ...