Test 2 Ch. 4 Flashcards
The inability to maintain either the normal delivery of o2 to the tissues or the normal removal of co2 from the tissues is defined as
Respiratory failure
What is the criteria for respiratory failure
PaCO2 > 50 mm Hg
PH < 7.25 and falling
What is another term for elevated PaCO2 results in uncompensated Respiratory acidosis
Hypercapnic Respiratory Failure
Hypercapnic Respiratory Failure akas
“pump failure” or “ventilatory failure”
Chronically elevated PaCO2 leads to
Acute ventilatory failure superimposed on chronic ventilatory failure
Ventilatory drive most commonly deminished by (5 diseases)
-Drug overdose
-Brainstem session
-Diseases of CNS (multiple sclerosis or Parkinson)
-Morbid obesity
-sleep apnea
Ventilatory failure may occur if
imposed workload cannot be overcome
increased WOB most commonly occurs secondary to
COPD
Asthma
Increased WOB can also be caused (3 disease)
- Pneumothorax rib fractures
- pleural effusion
- hypermetabolic states such as burns
Over months and years acute respiratory failure will become
Chronic Respiratory Failure
What is another term for acute hypercapnia failure
Acute Ventilation failure, Uncompensated respiratory acidosis
PH- 7.31
Paco2- 70
Hco3- 25
acute hypercapnia failure
Indications for Ventilatory Support (3)
- Constant therapy until underlying problem resolves
- provide long term support for its w/ chronic ventilatory failure
- support aimed at pt’s specific needs
Physiologic Indications for Vent support (5)
- Inadequate alveolar ventilation
- Inadequate lung expansion
- Inadequate muscle strength
- Increased WOB
- Very severe Hypoxemia
_______________ ______________ is a common indication for intubation and MV
Refractory Hypoxemia
Not responding to oxygen
refractory hypoxemia
Hypoxemia and hypercapnia respiratory failure occur
simultaneously
Elevated PaCO2 may or may not indicate for ventilatory support
Hypercapnia Respiratory failure
PaCO2 > 50 w/ ph falling below 7.25 =
acute process probably requires ventilation
PaCO2 > 50 w/ PH near normal =
chronic failure w/ renal compensation, probably does not require MV
The trend of PaCO2 and PH is very
useful
Diminished b/s in young asthmatic is known as
ominous — not moving adequate air
signs of worsening hypercapnia
Irritability, confusion, and coma
Respiratory muscle fatigue presents
- Tachypnea:cardinal sign of increased wob
- Worsening fatigue rr starts failing bradypnea occurs & apnea
Full ventilatory failure ABG
hypercapnia w/ acidosis
The primary purpose of ventilation is to maintain
homeostasis
Mechanical ventilation is indicated when a person
cannot achieve an appropriate level of ventilation to maintain adequate gas exchange and acid- base balance
Hypoxemia respiratory failure is a result of
server v/q mix match
Test to asses respiratory muscle strength
Maximum Inspiration Pressure (MIP)
Is the lowest (most negative) pressure generated during a forceful inspiratory effort against an occluded airway
MIP (PImax)
Device that Measures MIP, assess muscle strength and weakness
pressure monometer
MIP normal and critical ranges
-100 to -50
-20 - 0
normal and critical ranges maximul expiratory pressure (MEP)
100
<40
Vital Capacity normal and critical ranges
65- 75
<10- 15
Respiratory frequency normal and critical ranges
12- 20
<5
Forced expiratory volume at 1 second (FEV1) normal and critical ranges
50-60
<10
Peak expiratory flow (PEF) normal and critical ranges
350- 600
75-100
_____________ _____ is the most common cause of respiratory failure muscle fatigue and failure to wean from MV
Excessive WOB
Pts with _____________ ___________ usually require intubation an mv
profound hypoxemia
Indications for intubation where NIV may be poorly tolerated (4)
- Upper airway obstruction
- Inability to clear secretions and protect airway
- Inability to achieve proper mask fit
- Intolerance of the intervention
