Perform Procedure And Interpret Results Hemodynamic Monitoring Tracheal Tube Cuff Pressure Dean R. Hess PhD RRT FAARC Hemodynamic Monitoring Cardiac Rate and Rhythm Arterial Blood Pressure Central Venous Pressure Monitoring Pulmonary Artery Catheters Clinical use of hemodynamic measurements 1
Heart Rate (Pulse) Palpation of peripheral artery (e.g., radial) or central artery (e.g., carotid) Auscultation of cardiac apex (apical pulse) Should be counted for at least 15 s Can be measured from the ECG, bedside monitor, pulse oximetry Normal: 60 100 beats/min for adults; more rapid for children Heart Rate (Pulse) Tachycardia (> 100/min): anxiety, exercise, fever, drugs (beta agonists) Bradycardia (< 60/min): may be normal in athletes, drugs (beta blockers, digitalis), hypothermia, 3 nd degree AV block Irregular: premature contractions, atrial fibrillation, heart block, 2 nd degree AV block 2
Heart Rate (Pulse) Bounding: hypercapnia, fever, aortic regurgitation Weak: hypovolemia, heart failure Jugular Venous Distention Neck vein distention suggests a distended right ventricle Raise the head of the bed 45 degrees The vertical distance between the sternal angle and the highest level of jugular vein pulsation is measured Neck veins that fill to a level of > 2 cm is considered abnormal. 3
Arterial Blood Pressure Noninvasive technique Use a blood pressure cuff, which is gradually inflated around an extremity to a pressure above the systolic pressure Slowly deflated while the artery is auscultated for Korotkoff sounds Automated systems that measure changes in oscillation intensity Errors related to poor fitting cuffs Invasive: intra-arterial catheter Arterial Blood Pressure Normal: Systolic pressure: 90 140 mm Hg Diastolic pressure: 60 90 mm Hg Mean pressure: 65 105 mm Hg Respiratory variability in blood pressure during positive pressure ventilation suggests fluid responsiveness Pulsus paradoxus is an abnormally large decrease in systolic blood pressure during inspiration; occurs with asthma and COPD 4
CVP is measured in the superior vena cava; it is the filling pressure in the right atrium. Catheter passed into the superior vena cava Normal CVP: 0 8 mm Hg Elevated CVP Volume overload Right heart failure Pulmonary hypertension Right ventricular infarction Pulmonic stenosis Tricuspid valvular disease Left-to-right shunts Central Venous Pressure (CVP) Central Venous Pressure Pulmonary Artery Pressure (Balloon Deflated) Pulmonary Artery Occlusion (Wedge)Pressure Mixed venous oximetry Mixed venous blood gases Pulmonary Artery Catheter (Swan-Ganz) 5
Pulmonary Artery Pressure Normal: 15 30 mm Hg (systolic), 4 12 mm Hg (diastolic), 9 16 mm Hg (mean) Elevated: Left heart failure of any cause Primary lung disease Mitral valvular disease Pulmonary embolism Hypoxemia with pulmonary vasoconstriction Idiopathic pulmonary arterial hypertension Left-to-right shunts Pulmonary Artery Occlusion (Wedge) Pressure Normal: 2 12 mm Hg Elevated Left ventricular volume overload Left ventricular systolic dysfunction Primary left ventricular diastolic dysfunction Myocardial ischemia or infarction with decreased left ventricular compliance Mitral stenosis 6
Cardiac Output Thermodilution Fick Method Q = VO 2 / (CaO 2 - CvO 2 ) Normal cardiac output: 4 8 L/min Stroke volume: Cardiac output heart rate Mixed Venous Blood Gases PvO 2 /SvO 2 Blood from distal port of PA catheter Normal: PvO 2 35 45 mm Hg; SvO 2 70% - 80%; low level indicate tissue hypoxia Increased with sepsis Decreased with: Decreased oxygen delivery: decreased cardiac output, anemia, hypoxemia Increased oxygen uptake 7
Hemodynamic Monitoring Cardiac Rate and Rhythm Arterial Blood Pressure Central Venous Pressure Monitoring Pulmonary Artery Catheters Clinical use of hemodynamic measurements Cuff Pressure Measurement Air-filled cuffs Water-filled cuffs Foam-filled cuffs 8
Cuff Pressure Measurement: - Target pressure 20 30 cm H 2 O - Do not use minimal leak technique - High cuff pressure: tube misplaced, small diameter tube, tracheal dilation - Unable to maintain pressure: leak; replace tube is possible Tight-to-Shaft Cuff Tracheostomy Tubes Used for patients requiring short-term cuff inflation, such as avoidance of aspiration during feeding or nocturnal only ventilation. When totally deflated, adds no dimension to the outer diameter of the tube s shaft. Cuff is inflated with water rather than air. Monitor volume of water added to cuff 9
Foam Cuff: - Cuff deflated for tube insertion - Cuff normally open to air - Pilot balloon can be connected to ventilator circuit Cuff Pressure Measurement Air-filled cuffs: 20 30 cm H 2 O Tight to shaft cuffs: water filled Foam-filled cuffs: open to air or pressurized from ventilator circuit 10