Ventilació MecàNica Rpetits
-
Upload
martinezvegas -
Category
Health & Medicine
-
view
196 -
download
7
Transcript of Ventilació MecàNica Rpetits
1997
Spontaneous Breathing
ExhalationExhalation InspirationInspiration
Spontaneous Breathing
ExhalationExhalation InspirationInspiration
Normal Blood Gas Parameters
Arterial Mixed Venous
Normal Range Normal Range
pH, units 7.40 7.35-7.45 7.36 7.31-7.41
PCO2, mmHg 40 35-45 46 41-51
PO2, mmHg 97 80-100 40 35-40
O2Sat. % 97 95-100 75 70-75
HCO3, mEq/L 24 22-26 24 22-26
BE, mEq/L 0 +2 0 +2
Respiratory Tract
Tube + Balloon model
Airways
(Tube)
Alveoli
(Balloon)
O2CO2
Respiration
Ventilation– Mechanical
movement
– Pressure difference
Diffusion– Molecular movement
– Concentrationdifference
Perfusion
Precondition of Inspiration
Pa < Pb
– Spontaneousbreath
Pb > Pa
– Mechanicalventilation
PbPb
Pa
Gas Flow
PaPa << PbPb
Inspiration
Mechanical Breath
Spontaneous Breath
Pressure
Time
Alveolar Pressure Changes
Spontaneous Inspiration
Volume Change
Gas Flow
Pressure Difference
Mechanical Ventilation
Pressure Difference
Volume Change
Gas Flow
Pressure
Flow
Time
Volume Ventilation
Constant flow rate
Guaranteed tidal volumedelivery
Not affected by lungimpedance
Variable pressure
Increased Increased InspiratoryInspiratory Pressure Pressure
Compliance Compliance
Volume
Pressure
Volume Ventilation
Guaranteed tidal volume, not affectedGuaranteed tidal volume, not affectedby the changes in pulmonary mechanicsby the changes in pulmonary mechanics
“The Feature of the Tube”
Pressure Difference =Flow Rate x Resistance of the Tube
Pressure Difference =Flow Rate x Resistance of the Tube
R = PF
Airway Resistance
Pressure Ventilation
Constant insp. pressure
Decelerating, variableinspiratory flow rate
Time cycled: (A)– Pressure Control
Flow cycled: (B)– Pressure Support
Pressure
Flow
A B
Time CycledTime Cycled
Flow Cycled
Pressure Ventilation
Guaranteed pressure,Guaranteed pressure, is is not affectednot affectedby the changes in pulmonary mechanicsby the changes in pulmonary mechanics
Decreased Tidal VolumeDecreased Tidal Volume
Compliance Compliance
Volume
Pressure
Volume
Pressure
V
P
C = V P
Compliance
Control variables
Volume Ventilation Pressure Ventilation
Pressure
Flowtime
Pressure
Flowtime
Terminology: Flow and Volume
Minute Ventilation = Tidal Volume x Breath RateMinute Ventilation = Tidal Volume x Breath Rate
Pressure
Flow
Time
Tidal Volume Tidal Volume
Continuous Mandatory Ventilation
Control: Only machine initiated mandatory breaths:
Assist: Only patient initiated mandatory breaths:
Assist/Control: machine and patient initiated breaths:
Paw
Paw
Paw
CMV
Paw
Paw
Intermittent Mandatory Ventilation
IMV: Machine initiated + Spontaneous breaths
SIMV: Mandatory (patient or machine initiated) +Spontaneous breaths
SIMV + Pressure Support
Pressure supported spontaneous + Patient, ormachine-initiated mandatory breaths
Paw
(PSV)
Continuous Positive Airway Pressure
Pressure Support Ventilation
Paw CPAP
Paw PS
Spontaneous Modes
CPAP
PSV
Terminology: PEEP, I:E Ratio
Pressure
Time
Positive EndExpiratory Pr.
T insp. T exp. I : E = 1 : 2 I : E = 1 : 2
I : E = 4 : 1 I : E = 4 : 1
PEEP
PIP
PIP
PEEPT insp.
Atrapament = PEEPi
I
IIII
IIIE
EEE
E E E
Static and Dynamic Pressures
time
Pressure
PEEP
PIP
Pplat
Alveolar Distending (recoil) Pressure difference (Pdis)
Flow-ResistivePressure difference (Pres)
High Compliance
Indicates reduced elastic resistance oninspiration and a diminished expelling forceduring exhalation
Low Compliance
Indicates increased elastic resistance oninspiration and an increased expelling forceduring expiration
Found in patients with stiff lungs (RDS,Hypoplasia, pulmonary fibrosis, pulmonaryedema, pulmonary contusions, hemothorax,ileus)
Poden presentar insuficiència respiratoria els malalts que
estàn en VM ?
• Si, s’ha d’bservar si el malalt està desadaptat.
Normal
Fatiga diafragmàtica
Moment de retirada de la VM
Altres temes