Initiating mechanical ventilation.
A. Indications for continuous mechanical ventilation:
1. Apnea - not breathing (observation).
2. Acute ventilatory failure - not breathing enough (one ABG).
3. lmpending ventilatory failure - rising PaCO2 (serial ABG or decreasing VT, VC, MIP).
4. Oxygenation - last reason for ventilator, used to reduce work of breathing.
B. Patient Assessment - Clinical Data
1. Arterial Blood Gases.
2. Bedside Pulmonary Function.
3. Physiologic Assessment Calculations.
C. Initial Settings for Mechanical Ventilation
1. Ventilation mode.
a. Control, assisVcontrol, IMV/SlMV.
b. Any mode is acceptable for the initial set-up.
c. DO NOT RULE OUT AN ANSWER BECAUSE oF THE MODE ALONE.
2. Tidal volume, respiratory rate, FiO2 and PEEP.
3. Example of setting the initial parameters for mechanical ventilation.
A 23-year-old female (5'4", 60 kg, 132lb) is admitted to the ED following a drug overdose. Her arterial blood gases on room air are as
follows:
pH 7.24
PCO2 62horr
PO2 74 torr
HCO3- 26 mEq/L
The physician has written orders for intubation and mechanical ventilation' Which of the following are the most appropriate initial
ventilator settings?
a. SIMV mode, Vr 550, f 6, FrOz 55%, 6 cmH2O PEEP
b. AssisUcontrol mode, Vr 600, f 16, FrO2 40o/o,2 cmH2O PEEP
c. IMV mode, Vr 650, f 12, Fp265Yo, 15 cmHzO PEEP
d. Control mode, Vr 700, f B, FrO2 50o ,5 cmH2O PEEP