Physiologic Monitoring

Question 1

The point of critical oxygen delivery

Answer 1

(DO2crit)

Represents thhe transition from supply-independed to supply-dependent oxygen uptake and is INCREASED in sepsis

Question 2

Which is the least influenced by an underdamped or overdamped intra-arterial blood pressure monitoring system?

Answer 2

MAP

Question 3

Remarks on ECG monitoring in the ICU

Answer 3

Lead V4 is the most sensitive foe detecting perioperaitve ischemia and infarction
*V4 is NOT routinely monitored on a standard 3-lead ECG

Question 4

Remarks on EDP

Answer 4

The relationship between EDP and true preload is exponential.

Question 5

Remarks on ESP

Answer 5

The slope of end-systolic pressure-volume line will become steeper if contractility is increased

Question 6

The thermodilution technique for determining cardiac output

Answer 6

Is influenced by respiratory cycle due to changes in blood temperature and Qt
Qt is calculated by Stewart-Hamilton equation

Question 7

Vasopressor of choice for patients with septic shock

Answer 7

Norepinephrine

Question 8

Targeet MAP for sepsis

Answer 8

65mmHg

Question 9

Fluid res in seps

Answer 9

Minimum of 30mL/kg for hypotension or lactate >=4mmol/L

Question 10

Other goals in sepsis

Answer 10

CVP 8-12mmHg
UO >=0.5 mL/kg/h
ScVO2 of 70%
Or SVO2 of 65%

Question 11

Remarks on noninvasive methods of monitoring cardiac output

Answer 11

Impedance cardiography
Pulso contour analysis
*allow for continuous monitoring

Question 12

Remarks on PPV to determine preload responsiveness

Answer 12

“Pulse pressure variability”
Better predictor of preload responsiveness than CVP
Defined as the difference between the maximal pulse pressure and the minimal pulse pressure divided by the average of these two pressures

Question 13

Strategies for increasing oxygen delivery in mechanically ventilated, critically ill patients include

Answer 13

*Sao2 is dependent on mean airway pressure, Fio2, and SVO2.
The clinician can increase mean airway pressure by increasing PEEP or inspiratory time
SVO2 can be increased by increasing Hgb or Qt or decreasing oxygen utililzation (e.g. by administering a muscle relaxant and sedation)

Question 14

Remarks on airway pressures

Answer 14

PEAK AIRWAY PRESSURE is a function of the
-tidal volume
-resistance of airways
-lung/chst wall compliance
-peak inspiratory flow
PLATEAU AIRWAY PRESSURE isrelated to the
-lung/chest wall compliance
-delivered tidal volue
But is INDEPENDENT of
-airway RESISTANCE
-peak airway flow

Question 15

Causes of an increae in end-tidal-COD include

Answer 15

Reduced minute ventilation

increased metabolic rate

Question 16

Indications for monitoring ICP

Answer 16

GCS <= 8 with an abnormal CT scan
Severe TBI in a patient 40y/o and/or SBP <90, and/or unilateral/bilateral motor posturing (2 out of 3)
Acute subarachnoid hemorrhage with coma/neuro deterioration
Intracranial hemorrahge with intraventricular blood
Ischemic MCA stroke
Fulminant hepatic failure with coma and cerebral edema on CT

Question 17

Currently accepted uses of transcranial Doppler (TCD) include

Answer 17

Diagnosing vasopasms after subarachhnoid hemorrhage
Confirming brain death after clinical exam in patients under the influence of CNS depressants
Confirming brain death after clincinal exam in patients with metabolic enceph
*NOT for estimating ICP and CPP

Question 18

Remarks on jugular venous oximetry in patients with TBI

Answer 18

It requires placement of a catheter in the jugular bulb
Low Sjo2 is assoc’d with poor outcomes after TBI
Should be used in conjunction with icp and cpp monitoring (not alone)

Question 19

Remarks on monitoring local brain tissue oxygen tension (PbtO2) in patients with severe TBI

Answer 19

Has been shown to lower mortality when compared with ICP monitoring alone
Normal: 20-40mmHg
Critical values: 8-10mmHg
Adv
-early detection of brain tissue ischemia despite normal ICP and CPP
-may reduce potenntial adverse effects assc’d with therapies to maintain ICP and CPP