Egans chapter 46
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Egans chapter 46
The goal of breathing and circulation is..
Dead space units
Alveoil that are ventilated but not perfused
Alveoli that are perfused but not ventilated
Normal resting oxygen consumption is approximately...
Increases with activity, stress, and temp
Murray Lung Injury Scale quantifies the injury level using 4 factors:
Chest X ray findings
The most accurate and reliable measure of oxygenation efficiency is direct computation of...
The physiologic shunt (Qs/Qt)
Alveolar-Arterial Oxygen tension defference
P(A - a)O
Is a useful mesure of the efficiency of gas exchange
If elvated indicates gas exchange problem
A healthy person breathing room air has a P(A - a)O
5 to 15 mm Hg
100 - 150 if breathing 100%
The arterial PO
to inspired oxygentation has become important is the determination of the extent of acute lung injury (ALI) and Acute respiratory distress syndrome (ARDS)
Most reliable index of gas exchange when FiO
> .5 and PaO
A normal PaO
Ration while breating room air is...
About 400 to 500 mm Hg or greater than 380
Ration <300 mm Hg
Ration <200 mm Hg
The volume of oxygen used by the body in milliliters per minute
Oxygen consumption may be useful in determining:
Adequacy of oxygen delivery
May occasionally help determine the cause of high ventilation requriments
Alveoli that are receiving either partial ventilation or partial perfusion
Most accurate and reliable measure of oxygentation efficiency
Need arterial and mixed venous sample
What is the single best indicator of effective ventilation?
Normal compliance of lung and chest wall!
60 - 100 ml/cm H2O
1 -2 cm H2O/sec
5-10 for intubated patients
Peak airway pressure than 50-60 cm H
O is discouraged because...
Increasked risk of barotrauma and hypotension
Plateau pressure should not exceed...
30 cm H
It increases the risk of ventilator induced lung injury
Alters trigger sensitivity
Leads to errors in compliance calculations
Overcome with applied PEEP, decrease tidal volume, Increase E time
For healthy person the average total work of breathing is...
0.3 to 0.5 J/L
The normal VC is...
A VC less than 10 to 15 ml/kg indicates...
Considerable muscle weakness which may inhibit the ability to breathe spontaneously
Maximun Voluntary Ventilation
A measure used to assess respiratory muscle reserve, endurance, or fatigue
Normal MVV values for adults!
120 to 180 L/min
coast of breathing!
2-5 % of VO
Amount of O
consumes by ventilatory muscles
Central Venous-Right Atrial pressure
Is a measure of RA preload
The amount of venous return to the heart
What is the normal CVP!
2 to 6 mm Hg
It is the lowest of all heart chambers
Placement of a swan-ganz catheter allows...
Determation of CVP, PAP, and PCWP
Placement of catheter carries risk of...
The pressure that stretches the ventricular walls at the onset of ventricular contraction
Estimated with PCWP
LA pressure qhich reflects end diastolic pressure
Increased with LV failure
Normal arterial blood pressure!
Normal heart rate!
Normal pulmonary arterial pressure!
25/10 mm Hg
Normal pulmonary capillary wedge pressure!
5-10 mm Hg
Normal cardiac output!
Normal systemic vascual resistance!
900- 1400 dynes-sec/cm5
Normal pulmonary vascular resistance!
The load at which the ventricles must contract
reflected as increased in SVR
The muscle tension requried by the left ventricle to generate blood flow
Three primarily reason to measure Interacranial pressures:
to monitor patients at risk of life threatening intracranial hypertension
to monitor for evidence of infection
Th assess the effect of therapy aimed at reducing ICP
Normal mean ICP of a supine patient!
10 to 15 mm Hg
The ICU came out of the...
Polio epidemic of the 1950's
Signals or values may be inaccurate due to?
Caused by motion
shift or spike
real and out of range
temporary but may need attention
Normal sinus Rhythm
The PR interval is consistant
The QRS complex is no longer than 0.12
Recognized by irregular spacing between the QRS complex
First degree heart block
PR interval is longer than .20 sec
Premature ventricular contractions
The QRS is wider than normal
The most life threatening arrhythmia
Requries rapid defilbration and CPR