Monitoring of the Surgical Patient Flashcards
1
Q
Why do we do hemodynamic monitoring on a surgical pt?
A
- provides info as to the CP status of pt
- traditional clinical assessments are usually unreliable
- major changes in CV status may not be clinically obvious
- invasive techniquies must be utilized
2
Q
Indications for arterial catheterization? (ART line)
A
A. need for continuous BP monitoring
- shock states
- hypertensive crisis
- surgery in high risk pts
- use of potent vasoactiv or inotropic drugs
- controlled hypotensive anesthesia
- situations that may lead to rapid changes in cardiac fxn
B. need for frequent arterial blood sampling
3
Q
CI of Art lines?
A
No absolute CI relative CI: - bleeding problems (hemophilia) - anticoag therapy - presence of vascular prosthesis - local infection
4
Q
Sites for art lines?
A
- radial artery
- axillary artery
- femoral artery
- dorsalis pedis
- superficial femoral
- brachial
5
Q
Why is radial artery firstline choice for art lines?
A
- dual blood supply
- MC used site
- simple canulation
- low complication rate
- can perform modified allen’s test to assess ulnar artery, also doppler, plethysmography, pulse oximetry
6
Q
Use of axillary artery for art line?
A
- for long term monitoring
- large size
- close proximity to aorta
- deep location
- technical difficulty in insertion
- located near neurovascular structures
7
Q
Pros and cons for using femoral artery as art line?
A
- large size and superficial location
- but prone to atherosclerosis
- difficult to keep clean
8
Q
Why is the superficial temporal artery not used often for art lines?
A
- surgical exposure is reqd (cut down)
- neuro complications observed
9
Q
Use of brachial artery for art line?
A
- only for short term use
- risk of median nerve contracture (volkman’s contracture)
10
Q
Complications of art catheterization?
A
- failure to cannulate
- hematoma
- disconnection from monitoring system
- infection: catheters placed for more than4 days, surgical insertion, local inflammation
- retrograde cerebral embolization
- A-V fistula/pseudoaneurysm
- severe pain, distal necrosis
11
Q
What is central venous pressure monitoring? How is this done?
A
- this is a direct measurement of BP in the right atrium and vena cava
- it is acquired by threading a central venous catheter (subclavian double lumen central line) into any of the several large veins)
- threaded so that the tip of the catheter rests in lower 1/3 of SVC, pressure monitoring assembly is attached to distal port of multilumen central vein catheter
12
Q
Why use CVP for monitoring?
A
- in seriously ill pts the vital problem is determination of proper amt of fluids and blood requirements necessary to maintain an optimal blood volume in the:
preop
operative
postop - it is a reliable procedure to eval properly and promptly optimal fluid and blood requirement for these pts
- the procedure removes much of the guess work in rapid restoration and maintenance of adequate circulation w/o fear of overloading the heart
13
Q
Sites of CVP monitoring caths?
A
- subclavian vein:
easiest to cannulate, pneumothorax MC complication, difficult to control bleeding - internal jugular vein: lower risk of pneumothorax, arterial puncture MC complication
- external jugular vein
- basilic vein
14
Q
CVP is determined by what?
A
- it is measured anywhere in SVC or IVC or immediate tributaries
- it is determined by complex interaction of:
blood volume
cardiac pump action
vascular tone - serves as an index of circulating blood volume relative to cardiac pump action
- it will reflect ability of cardiac pump action to handle returning blood at particular time
15
Q
Indications for CVP?
A
- when massive blood replacement is instituted rapidly in rapid exsanguinating type of bleeding
- in acute blood vol deficit in cases operated for 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 nonhypovolemic from MI
- in elderly pts w/ limited cardiac reserve undergoing difficult, time consuming operations
- in surgical pts w/ anuria due to possible renal shutdown
16
Q
CVP levels?
A
- normal: 4-7 cm
- low: 0-3, indicates circulating blood vol is below normal blood vol the heart can handle
- high: 8-20, more than the heart can handle
17
Q
Indications for central venous catheterization?
A
- access for fluid therapy
- access for drug infusion
- parenteral nutrition
- CVP monitoring
- aspirate air embolism
- placement of cardiac pacemaker/vena cava filters
- hemodialysis access
- useful in hypotensive pts
- tracing for arrhythmias
- gives info about relationship b/t intravascular vol and R ventricular fxn
18
Q
Technique of central venous pressure monitoring?
A
- cannulation of SVC through basilic or cephalic veins
- polyethelen tube french 8 and 42 inches long inserted into basilic vein just above elbow and pushed up 20 inches
- connect an IV admin set to cenous cath through which IV fluid may be admin
- a manometer is connected to IV set w/ a 3 way stopcock, zero pt should be at level of atrium or approx at mid-axillary line
19
Q
When is swan-ganz pulmonary artery catheter used?
A
- PAC is the insertion of a catheter into pulmonary artery, its purpose is dx
- used to detect heart failure, sepsis, monitor therapy, and eval effects of drugs
- allows direct simultaneous measurement of pressures in:
R atrium
R ventricle
pulmonary artery
filling pressure (wedge pressure) of left atrium
20
Q
Indications for a PAC?
A
- management of complicated MI: hypovolemia vs cardiogenic shock, ventricular septal ruprure vs acute mitral regurg, LV failure, RV infarction, unstable angina
- assessment of respiratory distress: primary vs secondary pulm HTN, cardiogenic vs non-cardiogenic pulm edema
- assessment of any type of shock
- assessment of therapy:
afterload reduction, vasopressors, BBs - assessment of fluid requirement in critically ill pts:
hemorrhage, sepsis, acute renal failure aka acute kidney injury, burns - management of postop open heart surgical pts
- assessment of valvular heart disease
- assessment of cardiac tamponade/constriction
21
Q
How is the PAC inserted?
A
- percutaneously into major vein (jugular, subclavian, femoral) via introducer sheath
- preference considerations of cannulation of great veins are as follows:
- Right internal jugular vein: shortest and straightest path to the heart
- left subclavian: doesn’t require PAC to pass and course at an acute angle to enter SVC (compared to R subclavian or left internal jugular)
- femoral veins: distant, from which passing a PAC can be difficult, esp if R sided cardiac chambers are enlarged, often fluorsocopic assistance is necessary. Nevertheless, these sites are compressible and may be preferable if risk of hemorrhage is high
22
Q
Complications of CVP monitoring?
A
- catheter malposition
- dysrythmias
- embolization
- vascular injury
- cardiac, pleural, mediastinal, neuro injury
23
Q
Indications for respiratory monitoring?
A
monitoring ventilation and gas exchange
- decision making for the need of mechanical ventilation
- assessment of response to therapy
- optimize ventilatory management
- decision to wean from ventilator
24
Q
Components of ventilation monitoring?
A
- tidal volume: volume of air moved in or out in single breath
- vital capacity: max volume at expiration after max inspiration
- minute volume: total volume of air leaving the lung each minute
- physiologic dead space: portion of tidal volume that doesn’t participate in gas exhange:
anatomic dead space
physiologic dead space
25
What is involved in gas monitoring (respiratory monitoring)?
- reported as directly measured partial pressures (PO2 and PCO2)
- use of pulse oximeters for continuous measurements:
blood gas analysis:
efficacy of gas exchange
adequacy of alveolar ventilation
acid-base status
26
What is capnography?
- graphica display of CO2 concentration in wave form
available systems:
- infrared analysis
- mass spectrometry
- raman scattering
- disposable colorimetric devices
- semi-quantitativemeasurement of end-tidal CO2 concentration
27
Pulse oximetry use?
- reliable, real time est of arterial Hgb saturation
- wide clinical acceptance
- nail polish will throw off reading
28
What is gastric tonometry?
- relatively non-invasive monitoring of adequacy of aerobic metabolism in organs whose superficial mucosal lining is extremely vulnerable to low flow changes and hypoxemia
29
key pts in renal monitoring?
- kidney is excellent monitor of adequacy of perfusion
- prevention of renal failure
- predict drug clearance and proper dose adjustment
30
Urine output - for renal monitoring?
- commonly monitored but it can be misleading
- normal urine output: 0.5 ml/kg/hr
- correlates w/ GFR
- high output may not accurately reflect GFR (diabetes insipidus)
- may be affected by other factors
31
Glomerular fxn tests used in renal monitoring?
- BUN:
affected by GFR and urea production, increased in TPN, GI bleeding, trauma, sepsis, and steroid use, lowered in starvation, liver disease, not always reliable
- plasma Cr:
more accurate than BUN, directly proportional to Cr production, inversely related to GFR, not affected by protein or nitrogen production or rate of fluid flow through tubules, related to muscle mass
- Cr Cl:
used if values of plasma creatinine are affected by muscle disease, serial determination of urine is done and is currently the most reliable method of assessing GFR
32
Tubular fxn tests used in renal monitoring?
- most reliable test to distinguish pre-renal azotemia from tubular necrosis
- reqrs simultaneous collected urine and blood samples
33
Key pts in neuro monitoring?
- early recognition of cerebral dysfxn
| - facilitate prompt intervention and tx
34
Components of intracranial pressure monitoring?
- cerebral perfusion pressure greater than 70 mmHg
| - glasgow coma scale
35
What is electrophysiologic monitoring?
- reflects spontaneous and on-going electrical activity in the brain (EEG)
36
Fxn of a trans-crainal US?
- monitors cerebral blood flow
| - detects vasospasm
37
Fxn of jugular venous oximetry?
- measures relationship of blood flow to O2 consumption
38
Key pts to metabolic monitoring?
- caloric demands
| - respiratory quotient of food
39
Temp monitoring key pts?
- rectal
- middle ear
- esophageal: get good core temp
