Clinical Monitoring - Quiz 2 Flashcards
Standard V - Monitoring
Oyxgenation
Ventilation
Cardiovascular Status
Thermoregulation
Neuromusdcular Function & Status
Positioning
How does Pulse Ox Work?
Two Lights
- Red - absorbed by dexoyHGB
- Infrared - absorbed by oxyHGB
- Lights pass between two diodes through arterial bed
- Computer does its thing
Beer Lambert’s Law
Absorption of light by a solute to its concentration and at a given wavelength.
What can cause inaccurate Pulse Ox readings?
- Hypoperfusion - vasoconstriction, hypothermia, hypotension
- Motion aritifact
- Methylene blue
- Anemia: < 5g/dl
- Cautery Interference
What does not completely assure adequate gas exchange?
Airway Movement
Failure to intubate is ________, Failure to recognize misplacement is __________
Problematic
Catastrophic
Value of Precordial/Esophageal Stethoscope
Provides continuous assurance that ventilation is happening
Useful to detect changes in breath sounds
Esophageal stethoscope
Soft, plastic catheter with a balloon at the end
Only used with Intubated pts.
Can cause bleeding/irritation
What happens if esophageal stethoscope slides into trachea?
Gas leak around ETT
What does abscence of ETCO2 waveform indicate?
Esophageal Intubation
Accidental d/c from circuit
Cardiac Arrest
Difference between ETCO2 and Arterial CO2
ETCO2 is 2-5 torr lower
- A-B: Baseline, End of Inspiration, Beginning of Expiration
- B-C: Expiratory Upstroke - dead space + alveolar expiration
- C-D: Alveolar Emptying CO2
- D: Actual End-Tidal
- D-E: Rapid return to baseline after exhaling CO2
Gas Analyzer
Continual analysis of inhaled & exhaled respiratory and anesthetic gases
- Mass Spectrometry
- Infrared Spectrometry
- Monochromatic
- Polychromatic
- Raman Spectroscopy
Mass Spectrometry
Measures and reports all of patient’s gas simultaneously
Monochromatic Infrared Spectrometry
- 3.3 micrometer light passed through anesthetic gas sample.
- Absorption of Halogenated agents is at this wavelength
- Must set monitor to agent
Polychromatic Infrared Spectrometry
- 7-13 micrometer light pass through anesthesia gas
- Absorption of halogenated agents are different at this wavelength
- Monitor automatically identifies inhaled anesthetic
- Monitor can tell the concentration of gas being given
- Monitor can measure multiple agents at the same time
Raman Spectroscopy
Determines composition and concentration of gas in patient’s airway using the “Raman scattered light”
Peak Inspiratory Pressure Gauge
Measures positive pressure created by mechanical vent
- Low Pressure Disconnect
- Alarm
- Circuit Disconnect
- Leak in System
High Peak Inspiratory Pressure
- Alarm for pressure > 40cm H2O
- May indicate low pulmonary compliance
- Check for obstruction in system
Human Senses for Monitoring
Hand on Bag
Chest Movement
Listening with Precordial Stethoscope
Electrocardiography
NOT a measure of heart function - you can have a normal ECG with no cardiac output
LBBB needs to be stress tested if they dont have any history.
Monitoring Body Temperature
- All Pediatric Patients under general
- Body can’t compensate for hypothermia under general d/t hypothalamic interference
- Spinal/Epidural hypothermia d/t internal redistribution of heat. Sympathetic system causes vasodilation.
Peripheral Nerve Stimulation
- Pulse Generator
- Two Electrodes
- (+) Proximal Nerve
- ( - ) Distal Nerve
Common Sites for Monitoring Neuromuscular Function
Ulnar Nerve - pollicus muscle
Facial Nerve - orbicularis oculi muscle
Types of Nerve Stimulator Tests
- Single Twitch
- Train of Four (TOF)
- Tetany: Post Tetanic Potentiation:
- Double Burst Suppression
Electroencephalogram (EEG)
- Monitor cerebral fxn
- Provides early sign of ischemia
- Carotid Endartarectomy
- Cardiopulmonary Bypass
Evoked Potentials
- Electrical manifestation of brain’s response to external stimulus
- Used for procedures with risks of neuro injury
- Spinal Fusion
- Craniotomy
- Visual, Auditory, Somatosensory, and Motor Stimuli
Bispectral Index (BIS) Monitoring
- Processed EEG that reflects sedative & hypnotic effects
- 0 - 100
- < 60 = high probability of unresponsiveness & low awareness during surgery
- Goal is to maintain BIS near 60
Near Infrared Spectroscopy (NIRS)
Measures O2 Supply vs Demand
Ratio of Oxygenated HGB to Total HGB
Used in CV Bypass, Carotid, & Sitting Position
In regards to Cerebral Oximetry, what needs to be obtained before giving any medications
Obtain Baseline Cerebral Oximetry
Single Twitch
0.1 - 1 hz for 0.1-0.2 ms
Serves as control twitch
Train of Four
Four stimuli every 1/2 second at 2 Hz for 2 seconds
Fade - each twitch is smaller
All twitches equal when neuromuscle is free of NMBD
Tetanus
Continuous electrical stimulation for 5 seconds at 50 or 100 Hz
If no Fade: no signficant paralysis
If Fade: Significant block
Double Burst Stimulation
2 Short Bursts at 50 Hz separated by 0.75 seconds
Detects residual paralysis during recovery
Fade < 0.6 = significant paralysis?
What happens if a patient’s cardiac output if their pacemaker’s rate is inceased from 70 to 140?
Stroke volume will fall due to pacemaker stimulation
How does cardiac output relate to delivery of anesthetic gas to the brain?
Decreased Cardiac Output increases delivery of anesthetic gas
CO is inversely related to brain uptake.
The patient is hypotensive with an SVR of 750 dynes after losing blood. What should the nurse do?
Give vasopressors, blood products, and IVF
What factors increase PVR?
Acidemia, Vasoconstriction Drugs, Hypercapnia
What should be avoided with mitral stenosis or regurgitation?
Hypercarbia
How does a temp of 35.5 or hypothermia effect SVO2?
Increases mixed venous oxygen saturation
Which Lung Zone should the PA catheter tip be placed?
Zone III
As a PA catheter advances, DBP increases and dicrotic notch forms, where is the tip of the catether?
Pulmonary Artery
What is the length of the PA cath when it is in the Pulmonary Artery using a Left IJ site?
40-50 cm
Contraindications to placing a Swan
LBBB
RBBB
Triscuspid/Pulmonic Valve Replacements
Presence of Endocardial Pacing Leads
When should CVP be measured?
End Expiration
On an EKG, what is the starting point in measure ST segment?
J Point
Which electrode acts as the ground?
RL Lead - Green
Difference between Depolarizing and Non-Depolarizing Medications regarding nerve stimulation
Depolarizing (Succinylcholine) will either have twiches or not.
Non-Depolarizing will have fade
If patient has new on ST elevation in V3-V4, the most likely culprit is the RCA
False
