09: Vent Initiation Flashcards
Clinical goals of CMV
Improve ventilation and oxygenation
Decrease WOB and myocardial work
How to achieve CMV goals
Normalize pH
Improve alveolar ventilation
Arterial oxygenation
Increase lung volume
Four broad indications for CMV
Apnea
Acute hypercapnic failure
Impending acute ventilator failure
Acute hypoxemia respiratory failure
Acute hypercapnic respiratory failure signs
Respiratory acidosis
PaCO2 55 or greater
pH 7.20 or less
How to determine impending acute ventilatory failure
Serial ABGs
acute hypoxemia respiratory failure signs and systems and disease process this is common in
PaO2 <60
Increased WOB
Inefficient breathing pattern
Common in ARDS
Five steps in ventilator commitment
patent airway (artificial aw or ambu)
Stabilize cardio (hypotensive and arrhythmias)
baseline vitals
Respiratory pattern (initial parameters)
Connect pt to vent
Effect of peak flow on ventilation and I:E (increasing or too high)
Increasing peak flow -> decreases I time, increases E time, improve venous return
Too high peak flow -> increase PIP, turbulence, but decrease venous return
Artificial airway complications/hazards and how to manage
Tube disconnection -> set alarms, ambu bag
Sore throat, edema, etc -> use less than 25-30 mmHg of cuff pressure
Cuff over-inflation -> deflate, reintubate
Loss of cuff seal -> reinflate
VAP -> HOB 30 degrees, oral care, hi-lo eval secretions
Machine failure complications/hazards and how to manage
System leak -> locate leak, bag pt
Machine failure -> immediately remove pt from vent
Hypotension/hypovalemia in CMV cause of and effect on venous return
Tidal volume >8 ml/kg and pressures >7cmH2O cause decreased venous return
Pulmonary barotrauma in CMV complications/hazards, cause of, and what to do if pneumo is suspected
Pneumo, subq emphysema
PIP>50 and/or PEEP >20
Call dr/nurse, needle decompression for tension
Atelectasis in CMV: cause of and how to manage
Inefficient tidal volume (keep between 6-8 ml/kg IBW)
Change body positioning
Fluid management
Pulmonary infection in CMV:
Cause of
Immunosurpressed?
How to prevent
Signs to look for
Common site?
Direct contact w pt aw
Immunosuppressed? Get sick quick
Aw care/aseptic
Change in sputum
Common site? Headed humidifier
GI problems in CMV complications/hazards and how to manage
Acute ulcerations with bleeding -> HOB 30 degrees
Renal problems in CMV complications/hazards and how to manage
Fluid retention from increase in ADH
Mgmt: daily kg body wt check
O2 toxicity in CMV:
Cause of
Leads to
How to manage
FiO2 > 50% for 24-72 hrs
Absorption atelectasis
Hyaline membrane formation
Mgmt: ween FiO2 to 50% then PEEP
Hemodynamic changes in CMV:
Effect on blood flow
Bedside monitor?
L ventricle cannot pump blood to body -> cannot return to R side
Bedside monitor? BP
CNS (ICP) in CMV
Increased ICP (NV: 5-15) with PEEP and increased intrathoracic pressure
decreased CO -> decreased Cerebral perfusion -> increased ICP
Human error in CMV complications/hazards and how to manage
R main stem intubation
Poor sx technique
Inefficient alarms/parameters
Prolonged full ventilatory support in CMV complications/hazards
Atrophy
Fatigue
Insufficient alveolar ventilation parameters
PaCO2 >55
pH <7.20
Insufficient lung expansion parameters
Vt <5
VC <10
RR <8 or >35
Insufficient muscle strength parameters
MIP/NIF > -20
VC <10
Increased WOB (labored/distressed)
VE >10
VD/Vt >0.6
Hypoxemia parameters
P(A-a)O2 on 100% >350
PaO2/FiO2 <200
PIF/NIF tests
Respiratory muscle strength
What might prevent improved ventilation in CMV
Severe obstruction
Reduced LC beyond capability of vent (ARDS)
As alveolar ventilation decreases, PaCO2
Increases
As VA increases, PaCO2
Decreases
Alveolar ventilation equation
(Vt - VD) x RR
Vd =
1 ml/lb IBW
MAP or PAW =
Result of duration and amount of positive pressure in lung
Initial vent settings
FiO2: 100%
Mode: Control
Rate: 12-20 or rate needed to correct acidosis/alkalosis
Vt: 6-8 ml/kg IBW
How to alleviate cuff leak from severed pilot line
Reinflate w needle
O2 toxicity S&S
Nausea
Substernal chest pain
Ventilation strategy for increased ICP
Deliberate hyperventilation (PaCO2 30-35) for first 24-48 hrs to decrease swelling and ICP
Effect of subnormal workload on respiratory muscle
Atrophy
Effect of excessive workload on respiratory muscle
Fatigue
NIF normal range
-80 to -100
Acute hypoxemic RF ABG
PaO2 <60
Hypercapnic respiratory failure ABG
Uncompensated pH
Increased CO2
Acute on Chronic hypercapnic respiratory failure
Alveolar hyperventilation
CMV effect on WOB
Decreases
What effects MAP
PEEP
How does air trapping occur in CMV and how does it effect I and e time
Too low of flow -> increase I time decrease E time
Airtrapping results in
Decreasing pulmonary capillary blood flow
Increasing risk for barotrauma
Positive pressure effect on venous return
Decreases
Overly/more compliant lung and PPV
Emphysema
Worsen impact on cardiovascular
Stiff lung and PPV
ARDS
Less transmission of pressure, less effect on venous return
Kyphoscoliosis and CMV
Rapid transmission of pressures -> decreases venous return
Pt fighting ventilator? (Asynchronous)
Increases WOB -> increases intrapulmonary pressures -> decreases venous return
Status asthmaticus and circulation effect
No evidence of circulatory depression w high Raw
Fatigue in CMV: caused by and leads to
failure to provide adequate vent support or strenuous weaning, leads to hypoventilation/inadequate lung expansion and atelectasis
