PHYSIOLOGIC MONITORING OF SURGICAL PATIENT Flashcards
HEMODYNAMIC MONITORING
Indications for Arterial Catheterization
⦁ need for continuous BP monitoring
⦁ need for frequent arterial blood sampling
HEMODYNAMIC MONITORING
Conditions that need continuous & accurate BP monitoring
⦁ shock status
⦁ hypertensive crisis
⦁ surgery in high risk patients
⦁ use of potent vasoactive or inotropic drugs
⦁ controlled hypotensive anesthesia
⦁ situations that may lead to rapid changes in cardiac function
absolute contraindications to ART cath
NONE!
relative contraindications to ART cath
⦁ bleeding problems (hemophilia)
⦁ anticoagulant therapy
⦁ presence of a vascular prosthesis
⦁ local infection
- Sites for Arterial Catheterization
⦁ Radial artery ⦁ Axillary artery ⦁ Femoral artery ⦁ Dorsalis Pedis artery ⦁ Superficial temporal artery ⦁ Brachial artery
most commonly used site for arterial catheterization
radial artery
RADIAL ARTERY FOR ART CATH
- hand has dual blood supply (radial & ulnar)
- most commonly used site
- simple cannulation
- low complication rate
- Modified Allen’s Test = assess ulnar artery
- Doppler technique, Plethysmography, Pulse oximetry
MODIFIED ALLEN’S TEST
hand elevated, pt clenches fist x about 30 seconds. Pressure applied over ulnar & radial arteries (occlude both). Still elevated, hand is opened from fist - should be blanched/observe pallor. Then ulnar pressure is released, but maintain radial pressure. Color should return within 5-15 seconds
⦁ if color returns within 5-15 seconds, the Allen’s test = considered normal
⦁ if color fails to return, test considered abnormal, and it suggests that the ulnar artery supply to the hand is not sufficient = indicates that it may not be safe to use the radial artery. Try other hand…
AXILLARY ARTERY FOR ART CATH
- for long term monitoring
- large size
- close proximity to aorta
- deep location
- technical difficulty in insertion
- located near neurovascular structures
FEMORAL ARTERY FOR ART CATH
- large size & superficial location
- prone to atherosclerosis
- difficult to keep clean (near groin…)
SUPERFICIAL TEMPORAL ARTERY FOR ART CATH
- surgical exposure is required
- neurologic complications observed
BRACHIAL ARTERY FOR ART CATH
- for short term use only
- risk of median nerve contracture (Volkman’s contracture)
ARTERIAL CATHETERIZATION
- for short term
- for long term
- modified Allen’s test
- median nerve contracture risk (Volkman’s)
- prone to atherosclerosis
- easily inserted
- difficult to insert
- difficult to keep clean
- neurologic complication risk / surgical insertion
short term = brachial artery
long term = axillary artery
modified Allen’s test = radial artery
Volkman’s contracture risk = brachial artery
prone to atherosclerosis = femoral artery
easily inserted = radial artery
difficult to insert = axillary artery
difficult to keep clean = femoral artery
neurologic risk = superficial temporal artery
COMPLICATIONS OF ARTERIAL CATHETERIZATION
⦁ failure to cannulate
⦁ hematoma
⦁ disconnection from monitoring system
⦁ infection (if catheter in place > 4 days, if surgical insertion done. Local inflammation occurs)
⦁ retrograde cerebral embolization (AV fistula / pseudoaneurysm) - severe pain & distal necrosis
preferred site = radial artery
CVP MONITORING (central venous pressure)
CVP = direct measurement of blood pressure in right atrium & vena cava
- acquired by threading a central venous catheter (subclavian double lumen central line) into any of several large veins
- the line is threaded so that the tip of the catheter rests in the lower 3rd of the superior vena cava. The pressure monitoring assembly is attached to the distal port of a multilumen central vein catheter
why monitor cvp?
- In seriously ill patients, the vital problem is determining the proper amount of fluids and blood requirements necessary to maintain an optimal blood volume in the preop, operative, and postop phase
- CVP monitoring = reliable procedure to properly and promptly evaluate the optimal fluid & blood requirements in these patients
- the procedure removes a lot of the guess work in rapid restoration and maintenance of adequate circulation without fear of overloading the heart
- CVP = measured anywhere in the SVC or IVC or their immediate tributaries, such as the Innominate and the Common Iliac Veins
- CVP determined by a complex interaction of
⦁ blood volume
⦁ cardiac pump action
⦁ vascular tone - CVP measurement serves as an index of circulating blood volume relative to the cardiac pump action
- CVP determined by a complex interaction of
⦁ blood volume
⦁ cardiac pump action
⦁ vascular tone
- CVP measurement serves as an index of
circulating blood volume relative to the cardiac pump action
CVP will reflect the ability of the Cardiac Pump Action to handle the returning blood volume at that particular time
INDICATIONS FOR CVP MONITORING
⦁ when massive blood replacement is instituted rapidly in rapid exsanguinating type of bleeding
⦁ In acute blood volume deficit in cases where the pt had surgery for a strangulating type of intestinal obstruction, where rapid fluid replacement is indicated
⦁ In obscure cases of shock immediately post-op, whether hypovolemic due to internal bleeding, or non-hypovolemic from MI
⦁ In elderly patients with limited cardiac reserve, who are undergoing difficult & time consuming operations
⦁ In surgical patients with anuria due to possible renal shutdown
normal CVP
4-7
Normal CVP = 4 - 7 cm/H2O
o a low CVP (0-3) indicates that the circulating blood volume is below the normal blood volume that the heart can handle
o a high CVP (8-20) indicates that the circulating blood volume is more than the heart can handle
a low CVP indicates that
a high CVP indicates that
o a low CVP (0-3) indicates that the circulating blood volume is below the normal blood volume that the heart can handle
o a high CVP (8-20) indicates that the circulating blood volume is more than the heart can handle
INDICATIONS FOR CENTRAL VENOUS CATHETERIZATION
⦁ access for fluid therapy ⦁ access for drug infusion ⦁ parenteral nutrition ⦁ CVP monitoring (aspirate air embolism) ⦁ placement of cardiac pacemaker / vena cava filters ⦁ hemodialysis access
OTHER USES FOR CENTRAL VENOUS CATHETERIZATION
⦁ useful in hypotensive patients
⦁ tracings for arrhythmias
⦁ provides information about the relationship between intravascular volume and right ventricular function
most common complication of venous catheter in subclavian vein
pneumothorax