Dr. Abdul-Monim Batiha Monitoring in Critical Care Dr. Abdul-Monim Batiha

General Guidelines Monitoring ensures rapid detection of changes in the clinical status Allows for accurate assessment of progress and response to therapy When clinical signs and monitored parameters disagree, assume that clinical assessment is correct Trends are generally more important than a single reading Use non-invasive techniques when possible Alarms are crucial for patient safety

Hemodynamic Monitoring Blood Pressure Can be measured intermittently with a cuff or continuously with an arterial line BP does not reflect CO – BP can be high with a low CO if vasoconstriction occurs and vice versa Central Venous Pressure (CVP) Measured in internal jugular vein or subclavian vein, reflecting right atrial pressure May be used to assess volume

Hemodynamic Monitoring, cont… Pulmonary Artery Wedge Pressure (PAWP) Reflects left atrial pressure Normal is 6-12 mm Hg Cardiac Output (CO) Usually measured by thermodilution PA catheter Can also be measured by dye dilution, transesophageal Doppler, echo, or impedence plethysmography EKG Monitors rate and rhythm of heart

Respiratory Monitoring ABG Monitors acid-base balance, PaO2, and PaCO2 Oxygen Saturation SpO2, using a finger or other probe, measures the proportion of saturated to desaturated hemoglobin Requires adequate perfusion for accuracy Oxygenatio is OK if SpO2 >90%

Respiratory Monitoring, cont… Mixed venous O2 saturation (SvO2) Measured with PA catheter Normal is 65-75% Low SvO2 may indicate inadequate tissue O2 delivery (even if arterial O2 is OK) Lung Function Aa gradient and PaO2/FiO2 ratio measure the adequacy of gas exchange Arterial to end-tidal CO2 gradients indicate the adequacy of ventilation PF, FEV1, and FVC help assess patients with lung dx MIP/NIF is used to determine readiness for extubation

Respiratory Monitoring, cont… Respiratory compliance Vt/PIP-PEEP A measure of the ease of inflation High airway pressures during mechanical ventilation may be caused by low compliance Capnography End-tidal CO2 concentration is close to artrial PaCO2 levels Indicates the adequacy of alveolar ventilation

Organ and Tissue Oxygenation Global measures Reflect the adequacy of total tissue perfusion but could be normal with local perfusion abnormalities Increased lactate concentration and metabolic acidosis suggests anaerobic metabolism and inadequate tissue oxygenation…lactate also increases with liver failure and sepsis, though SvO2 <55% indicates global tissue hypoxia

Organ and Tissue oxygenation Organ-specific Measures Urine flow A sensitive indicator of renal perfusion provided the kidneys aren’t damaged Normal is 1ml/kg Core-peripheral temperature The gradient between peripheral (skin) temp and core (rectal) is often used as an index of peripheral perfusion The less perfusion, the colder the periphery

Organ and Tissue Oxygenation Organ-specific Measures Gastric tonometry Used to detect shock-induced splanchnic ischemia by measure gastric luminal PCO2 and deriving the mucosal pH Neurological monitoring Utilizes GCS, ICP measurement, and jugular venous bulb saturation