Monitoring

Front 1

ASA Monitoring Standards

Back 1

Standard I: Qualified personnel must be present in the OR for continuous monitoring of the patient throughout EVERY anesthetic
Standard II: Oxygenation, ventilation, circulation, & temperature evaluated continuously.

Front 2

Standard II Monitors

Back 2

1. O2 analyzer
2. Pulse Ox
3. Clinical evaluation of ventilation
4. Confirmation of ETT placement via ETCO2 and clinical assessment
5. Disconnect alarms on vent
6. EKG and BP q 5 min
7. Temperature

Front 3

AANA Standards

Back 3

I: Complete preanesthetic evaluation
II: Informed consent
III: Patient specific anesthesia plan
IV: Implement and adjust anesthesia plan based on the pt's physiologic responses
V: Monitor patient's condition

Front 4

AANA Monitoring Guidelines

Back 4

1. Continuous monitoring of ventilation, oxygenation, CV status
2. Body temp. on all peds pt's and adults when indicated
3. Neuromuscular fxn when NMB's are used
4. Pt. positioning

Front 5

Classification of Monitors

Back 5

1. Requiring no instrumentation
2. Non-Invasive Monitors
3. Minimally invasive monitors
4. Invasive monitors

Front 6

Monitors Requiring NO Instrumentation

Back 6

1. Physical Assessment/Clinical Evaluation
a. Inspection
b. Palpation
c. Auscultation

Front 7

Non-Invasive Monitors

Back 7

1. NIBP
2. EKG
3. Pulse Ox
4. Capnography
5. Gas Analysis

Front 8

Minimally Invasive Monitors

Back 8

1. Temperature
2. Renal Function (Foley)

Front 9

Invasive Monitors

Back 9

1. Central Line
2. Arterial Line

Front 10

Physics of the NIBP

Back 10

A microprocessor oscillometric monitor senses cuff pressure whose output is translated to a numeric signal
- the point of max. fluctuation is the blood pressure

Front 11

SBP

Back 11

Correlates with myocardial O2 requirements

Front 12

DBP

Back 12

An important determinant of coronary perfusion

Front 13

MAP

Back 13

Used to estimate organ perfusion
= SBP + 2(DBP)/3

Front 14

EKG

Back 14

* Standard of care for all anesthetized patients; providing detection of:
1. Cardiac dysrhythmias
2. Myocardial ischemia (ST depression)
3. Electrolyte disturbances (K+)
4. Heart Rate
5. Pacemaker function (intrinsic)

Front 15

EKG Lead II

Back 15

Displays easily recognized p-waves (first upward deflection from the isoelectric line)
**Increased sensitivity to inferior wall ischemia**

Front 16

EKG Lead V5

Back 16

Views the anterior and lateral portion of the LV
**Best lead for detecting ischemia (ST segment depression)**

Front 17

Pulse Oximetry

Back 17

* Standard of care for continuous monitoring of peripheral arterial Hgb saturation
- SpO2 is a reflection of SaO2
- Provides an early warning of arterial hypoxemia
**Assesses tissue perfusion and HR**
-Lateral positioning: pulse ox on 'down arm' monitors perfusion

Front 18

Lambert-Beer Law

Back 18

The observation that oxyenated Hgb and reduced Hgb (already given up O2)
- absorb red and infrared light differently
- absorb wavelengths of light differently

Front 19

Physics of the Pulse Ox

Back 19

2 light emitting diodes (LED) which projects 2 wavelengths and a sensor
- Infrared light: 940 nm
- Red light: 660 nm

Front 20

Pulse Ox Limitations

Back 20

1. IV dyes: transient false low
2. Low perfusion states (cold, CPB, hypotension, vasoconstriction): inaccurate
3. Carbon monoxide poisoning: false high d/t carboxyhemoglobin also absorbs light @ 660nm

Front 21

Capnography

Back 21

**AANA Standards: ETT placement must be verified via presence of ETCO2**
- Continuous measurement of inhaled and exhaled CO2
- Effective for monitoring alveolar ventilation

Front 22

Capnography Physics

Back 22

Two beams of infrared light are passed through a sampled exhaled gas chamber & a control-calibrated CO2 chamber. The quantity of light absorbed in both chambers is calculated and the ETCO2 is displayed as a # and waveform.

Front 23

Arterial vs. Alveolar CO2

Back 23

**A gradient exists (monitor vs. blood gas)**
Arterial (PaCO2) 4-6mmHg> Alveolar (ETCO2)

Front 24

Capnography Waveform

Back 24

A-B: No CO2=Dead Space
B-C: Sharp upstroke, alveolar emptying
C-D: Exhalation of alveolar gas
D: ETCO2 reading
D-E: Begin inspiration

Front 25

Capnography Abnormal Waveforms

Back 25

1. Increased ETCO2
2. Decreased ETCO2
3. Curare cleft
4. Obstructive pattern
5. Restrictive pattern

Front 26

Causes of Increased ETCO2

Back 26

1. TQ Release
2. Exhausted Soda Lime (neutralizes CO2)
3. Faulty unidirectional valves (condensation)
4. Inadequate FGF
5. Hypoventilation
6. Shivering
7. Laparoscopy
8. Increased metabolic states (fever, MH)
9. Obstruction in breathing circuit

Front 27

Causes of Decreased ETCO2

Back 27

1. Hyperventilation
2. PE/embolus of any kind
3. Disconnect in breathing circuit
4. Cardiac arrest (hypotension-esp. rapid drop in BP)
5. Apnea
6. Esophogeal intubation
7. Increased dead space

Front 28

Gas Analysis

Back 28

Permits the monitoring of inhaled and exhaled concentrations of respiratory (O2, CO2, N) and anesthetic (volatile agents, N2O) gases

Front 29

Physics of Gas Analysis

Back 29

Mass Spectrometry: gases are sampled from the circuit, ionized by an electronic beam. Acc. to molecular weight identified and displayed on the monitor and returned to the breathing circuit.

Front 30

Disadvantages of Mass Spec.

Back 30

- Only analyzes gases for which it has plates
- 200 ml of gas is sampled; decreasing fresh gas in circuit

Front 31

Temperature

Back 31

A redistribution in body heat from the core to the periphery decreases core temp 1-5 degrees Celsius during the 1st hour of anesthesia->hypothermia

Front 32

Complications of Perioperative Hypothermia

Back 32

1. Shivering (Increases demand on myocardium)
2. Impaired coagulation
3. Slowed metabolism
4. Delayed awakening
5. Increased incidence of wound infection
**Decreases in core temp of 1-3 degrees prevent cerebral ischemia**

Front 33

Types of Body Heat Loss

Back 33

1. Radiation
2. Convection
3. Conduction
4. Evaporation

Front 34

Radiation

Back 34

MOST common. Loss of heat with release of infrared rays. Influenced by cutaneous vasodilation. >50% of heat loss in adult surgical pt.

Front 35

Convection

Back 35

Warm air moves away, cold air takes it's place. 12% of heat is lost through convection.

Front 36

Conduction

Back 36

Heat lost from patient to inanimate objects (table)

Front 37

Evaporation

Back 37

Water from skin and lungs evaporates into atmosphere. *Burn patients*

Front 38

Causes of Intraoperative Hypothermia

Back 38

1. GA
2. Muscle relaxation
3. Cold IVF's
4. Open surgical site
5. Exposed skin
6. Cold environment

Front 39

Temp. Monitoring Sites

Back 39

**1. Esophageal: Most common, core temp. Contraind. in gastric bypass, esophagectomy)
2. Skin (least accurate)
3. Nasopharynx
4. Rectum (slow to respond to intervention)
5. Bladder (slow to respond to intervention)
6. Tympanic membrane
7. PA-core temp., not practical

Front 40

Maintaining Normothermia

Back 40

**1. Forced air warming blanket: most effective
2. Fluid warmers
3. Room temp > 21 C
4. Warm blankets (LEAST effective)
5. HME
6. Plastic covering

Front 41

Renal Function

Back 41

Measurement of UO provides information re:
1. Cardiac output
2. Organ perfusion
3. Intravascular volume

Front 42

UO Goals

Back 42

0.5-1 ml/kg/hr= 30 ml/hr

Front 43

Causes of Decreased UO

Back 43

1. Sympathetic stim. (ADH secretion)
2. Low systemic BP
3. Decreased C.O.

Front 44

Neurologic Monitors

Back 44

1. EEG
2. Bispectral Analysis (BIS)
3. Somatosensory Evoked Potentials (SSEP)
4. Motor Evoked Potentials (MAP)
5. Brainstem Auditory Evoked Potentials (BAEP)
6. Visual Evoked Potentials (VEP)
7. Facial Nerve Monitoring
8. Cerebral Oximetry

Front 45

EEG

Back 45

Represents the spontaneous electrical activity of the cerebral cortex.
**Useful for detecting cerebral ischemia**
- Carotid Endarterectomy
- Deliberate Hypotension
- Identification of epileptic foci
- Assessment of coma/brain death

Front 46

BIS

Back 46

(Bispectral Analysis)
* 2 lead EEG and EMG used to assess LOC
-sensor on forehead
-#'s correlate with LOC
0: no brain activity
40-60: GA
100: awake

Front 47

SSEP

Back 47

(SomatoSENSORY Evoked Potential)
* Monitor of the fxnl integrity of specific neural pathways (sensory pathways in the dorsal column of the spinal cord)

Front 48

Physics of the SSEP

Back 48

* Small electrical current is delivered to a peripheral nerve while brain responses are recorded via scalp electrodes (tiny needles)

Front 49

SSEP Considerations

Back 49

* Only SENSORY, not MOTOR pathways are assessed
* Anesthetic technique can affect reading
- N2O increases latency and decreases amplitude of SSEP waveforms
-Volatile agent can also effect wave forms in the same way
**Anesthesia technique: 1/2 MAC of gas; supplement with propofol**

Front 50

MEP

Back 50

(Motor Evoked Potentials)
- Stimulation of the motor cortex elicits peripheral nerve signals, EMG signals, or limb movements on the contralateral side
**From head to periphery**
- Pt. intermittently performs motor tasks (No NMB!)

Front 51

MEP Considerations

Back 51

* Wake-Up Test
- High incidence of recall
- Counsel pt. pre-op
* Anesthetic Technique
- Sensitive to volatile agents
- Consider topical lidocaine to prevent coughing during wakeup
(Propofol, dexmedetomidine, remifentanyl)

Front 52

BAEP

Back 52

(Brainstem Auditory Evoked Potentials)
* 8th CN is stim. with auditory signal (headset with clicking sound)
* Recordings made of input from 8th CN to cerebral cortex

Front 53

Indications for BAEP

Back 53

1. Cerebellar tumor
2. Hearing test for infants. (Post-myringotomy)

Front 54

VEP

Back 54

(Visual Evoked Potentials)
OPTIC nerve is stimulated. Stimulus is transmitted to the visual cortex in the occipital lobe.

Front 55

Indications for VEP

Back 55

1. Pituitary resection
2. Trans-sphenoidal surgery

Front 56

Facial Nerve Monitoring

Back 56

Facial nerves stimulated under direct visualization to assess integrity

Front 57

Indications for Facial Nerve Monitoring

Back 57

1. Posterior fossa craniotomy
2. Neck dissection
3. Ear surgery

Front 58

Arterial Cannulation

Back 58

* Direct BP mgmt.
A cannulated artery is connected to an external tubing device under pressure. The tubing is connected to a transducer that delivers pressure info to a microprocessor; converting in a numeric value on the monitor.

Front 59

Indications for Arterial Cannulation

Back 59

1. CABG
2. Neurosurgery
3. Deliberate hypotension
4. Vasopressor use
5. Hemodynamic instability
6. Frequent blood sampling (parathyroidectomy)
7. Critically ill patient
8. Any pt. the anesthesia provider deems appropriate

Front 60

Potential Arterial Cannulation Sites

Back 60

1. Radial
2. Ulnar
3. Dorsalis Pedis
4. Axillary
5. Femoral

Front 61

Radial Artery Advantages

Back 61

**Most common** Easily palpated and accessed. Usually adequate collateral flow.

Front 62

Radial Artery Disadvantages

Back 62

Must have collateral blood flow. Complications d/t clot formation.

Front 63

Ulnar Artery Advantages

Back 63

Easy access. Good collateral flow.

Front 64

Ulnar Artery Disadvantages

Back 64

Technically difficult. Runs deeper and more tortuous.

Front 65

Dorsalis Pedis Advantages

Back 65

2nd most common site. Low complication rate & easy access.

Front 66

Dorsalis Pedis Disadvantages

Back 66

**SBP 20-30 mmHG higher/(lower) than radial artery** depending on co-existing disease or positioning.

Front 67

Axillary Advantages

Back 67

Large, easily palpable artery.

Front 68

Axillary Disadvantages

Back 68

**High incidence of nervew damage d/t proximity to median nerve**

Front 69

Femoral Advantages

Back 69

Large, easily palpable artery

Front 70

Femoral Disadvantages

Back 70

Poor accessibility

Front 71

Arterial Waveform Components

Back 71

1. Ventricular contraction
2. Aortic valve closure
3. Systemic Vascular Resistance
4. Stroke volume

Front 72

Ventricular Contraction

Back 72

- Sharp upstroke (anacrotic limb)
- A sharp, vertical line correlates with good contractility

Front 73

Aortic Valve Closure

Back 73

- Dicrotic notch
- When ventricular pressure declines below the pressure in the aortic root, the aortic valve closes. **The small upstroke is caused by flushing back against the aortic valve: where coronary perfusion occurs**

Front 74

Systemic Vascular Resistance (SVR)

Back 74

- Dicrotic (downstroke) limb
- Represents fall in pressure at the aortic root as blood flows to the peripheral circulation
(An elevated SVR will exhibit a high dicrotic notch within the downward slope)

Front 75

Stroke Volume (SV)

Back 75

Area under the waveform

Front 76

Complications of Arterial Access

Back 76

**1. Thrombosis (MOST common)**
2. Emboli formation
3. Hematoma formation
4. Artery spasm
5. Neurologic Injury

Front 77

Central Venous Pressure (CVP) Monitoring

Back 77

Serves as an indicator of intravascular volume, preload, and cardiac performance

Front 78

Indications for CVP Monitoring

Back 78

- Usually monitored in pt's with good LV fxn who are undergoing surgical procedures involving:
1. rapid volume shifts
2. risk of large blood loss
**3. risk of venous air embolism**
Also:
1. Hypotensive pt's
2. Oliguric pt's
3. Pt's on hyperalimentation or vasoactive drugs
4. Pt's without adequate peripheral access

Front 79

CVP

Back 79

**CVP = RA = RVEDV in the absence of tricuspid valve obstruction**
- significance of monitoring is from the relationship of preload as RA pressure to ventricular output

Front 80

Preload

Back 80

= VOLUME of venous return to the heard
(to increase pt's preload; give volume)

Front 81

Afterload

Back 81

= PRESSURE that the LV must pump against. A measure of impedance to ventricular ejection.

Front 82

Sites for CVP Access

Back 82

1. IJ
2. SC

Front 83

Internal Jugular

Back 83

1. MOST common
2. Within carotid sheath adjacent to carotid artery
3. Right IJ allows for direct route to RV; facilitating PA catheter insertion
**Tip of catheter sits in SVC near junction of RA**

Front 84

Subclavian

Back 84

1. More difficult
2. Higher incidence of pneumothorax and hematoma

Front 85

Complications of CVP Access

Back 85

1. Pneumothorax
2. Vessel perforation
3. Air embolus
4. Thrombosis
5. Dysrhythmias
6. Infection
7. Nerve injury
8. Thoracic duct injury
9. Catheter knotting

Front 86

CVP Waveform

Back 86

1. a-wave
2. c-wave
3. x-wave
4. v-wave
5. y-wave

Front 87

a-wave

Back 87

Atrial contraction. During RA contraction, the tricuspid valve remains closed causing an increase in RA pressure. This increase is depicted by the sharp upstroke of the a-wave.

Front 88

c-wave

Back 88

Increase in RA pressure. The RA relaxes and RV contraction occurs causing the tricuspid valve to bulge up toward the RA.

Front 89

x-wave

Back 89

RV ejection. RV ejection causes emptying of blood from the ventricles; rapid decrease in pressure.

Front 90

v-wave

Back 90

Venous return. Immediately after RV ejection; increases RA pressure.

Front 91

y-wave

Back 91

Opening of the tricuspid valve. Allows blood to flow into RV; decreasing pressure in RA.

Front 92

Normal CVP (RA pressure)

Back 92

1-8 mmHg

Front 93

Pulmonary Artery (PA) Pressure Monitoring

Back 93

1. Right sided intracardiac pressure
2. Left sided intracardiac pressures
3. CO
4. Mixed venous saturation

Front 94

PCW/PAWP

Back 94

Reflects LVEDV in the absence of pulmonary disease or valvular dysfunction

Front 95

**Indications for PA Pressure Monitoring**

Back 95

1. Major surgery (open heart) with large fluid shifts
2. Ventricular dysfunction
3. CHF
4. Severe valvular disease
5. Conduction disturbances requiring pacing
6. CABG/valve surgery
7. AAA
8. Liver or lung transplant
9. Shock states: sepsis, hypovolemia
10. Large body surface area burns

Front 96

Normal Pressures During PA Catheter Insertion (Right IJ approach)

Back 96

RA/RVEDVP/CVP: 1-8 mmHg
RV: Systolic 15-25 Diastolic 1-8
PA: Systolic 15-25 Diastolic 8-15
PCW/PAWP: 6-12

Front 97

PA Catheter cm lengths for Right IJ approach

Back 97

1 hash mark = 10 cm
RA: 20 cm "balloon up"
RV: 30-35 cm
PA: 40-45 cm
PCW/PAWP: 50-55 cm

Front 98

Complications of PA Pressure Monitoring

Back 98

1. Cardiac dysrhythmias
2. Catheter kinking, knotting
3. RA, RV perforation
4. PA rupture
5. Pneumothorax
6. Pulmonary infarction (persistent wedge)
7. Bacterial endocarditis

Front 99

Pressure Variations/Treatment: Hypervolemia, Vasoconstriction

Back 99

- Increased CVP, CI, PCWP, PAP
Tx: diuretics, restrict fluids

Front 100

Pressure Variations/Treatment:
Hypovolemia

Back 100

- Decreased CVP, CI, PCWP, PAP
Tx: volume (crystalloid, colloid)

Front 101

Pressure Variations/Treatment:
LV Failure, Increased Afterload

Back 101

- Increased/Decreased CVP, Decreased CI, Increased PCWP, Increased PAP
Tx: Inotropes,alpha-adrenergic antagonists

Front 102

Pressure Variations/Treatment:
Pulmonary Edema

Back 102

- Increased CVP, Decreased CI, Increased PCWP, Increased PAP
Tx: Diuretics

Front 103

Pressure Variations/Treatment:
RV Failure, Increased Preload

Back 103

- Increased CVP, Decreased, CI, Decreased PCWP, Decreased PAP
Tx: Vasodilators (nipride, nitro)

Front 104

Phlebostatic Axis

Back 104

An imaginary line from the 4th intercostal space at the right side of the sternum intersecting with the mid axilla. Correlates with the location of the RA; where transducers should be leveled.

Front 105

Venous Air Embolus (VAE)

Back 105

- HR when operative site is above the level of the heart; air entrainment into systemic circ.

Front 106

VAE Sequelae

Back 106

hypoxia, **hypoercarbia** (initial decrease in CO2), bronchoconstriction, hypotension...CV collapse

Front 107

Devices Used to Detect VAE

Back 107

1. TEE: MOST sensitive, air visualized in heart as 'fireflies'
2. Transthoracic doppler: 'millwheel murmur
3. ETCO2: sudden decrease, over time becomes elevated
4. PA Catheter (central venous access/long arm catheter) for prompt aspiration of air
5. Esophageal stethoscope: 'Millwheel' murmur

Front 108

VAE Treatment

Back 108

1. Ask surgeon to flood/pack field
2. DC N2O (expands air spaces)
3. Aspirate blood/air from central venous catheter
4. Left lateral positioning keeps air in right side of heart preventing entrance into arterial blood and migration of embolus to brain.