Ventilator Flashcards
Average minute ventilation
4-8 LPM
Normal Vt
6-8 ml/kg
Exhaled tidal volume (Vte)
Important measure for pressure Control
- measurement of volume received by pt.
- breath by breath variation: pt lung characteristics
- should be within +/- 50 ml Vt
I:E ratio adults / Peds / RAD
Adult- 1:2
Peds - 1:3
RAD- 1:4
PEEP restores:
Functional residual capacity
Pressure support
Function that Can be added to SIMV
- turbo boost at beginning of pt triggered breath.
- augmentation of pt spontaneous breath.
- used to help wean.
- at least 5 above PEEP
Pressure controlled Ventilation indications
Challenging pts, ARDS, Trauma.
Children due to high risk barotrauma.
Any pt w/ possible compliance issues.
Pressure control ventilation disadvantage
Watch closely. No guarantee on Ve due to Vt based on compliance.
Pressure regulated volume controlled ventilation (PRVC)
New standard in children. Form of AC. Vent initiated (controlled), patient initiated (assist). Constant pressure applied throughout. Plateau checked w/ initial volume administered breath. Subsequent are pressure administered. Breaths adjusted breath to breath. Compares delivered Vt to set Vt. Longer inspiratory time.
Longer inspiratory time =
Improved O2 & alveolar recruitment.
-can cause gas trapping & auto peep.
PRVC upper pressure limit.
Vents deliver pressure up to 5cm below upper pressure alarm pressure.
-set to 35-40 cm to ensure safe pressures.
PRVC Test breath shows more Vt compared to set Vt, how should you adjust?
Decrease inspiratory pressure
PRVC Test breath shows less Vt compared to set Vt, how should you adjust?
Increase inspiratory pressure.
Airway pressure release ventilation (APRV)
Severely hypoxic ARDS pts.
-short expiratory time (0.4-0.6 seconds), prolonged inspiratory time (4-6sec), (always implies severe inverse I:E ratio)
O2 consumption for non-intubated person
60 cc/kg/min
O2 consumption for intubated pt:
120 cc/kg/min
O2 consumption for DKA or ASA pt?
240 cc/kg/min
How can we use O2 consumption to figure RR?
Divide calculated Ve (o2 consumption) by desired Vt = RR
Vent circuit & ETT Dead Space
150 ml
Ideal Body Weight Calculation
5' = 50, then multiply every inch above 5' by 3 and add to 50 5'10" = 50 + 30= 80 kg
Plateau Pressure
Most sensitive reading for alveolar pressure
-can only be checked on volume delivery.
Obstructive strategy
Asthma & COPD exacerbation only.
- increase E times, lower rates
- FiO2: 40-60% (not an oxygenation problem)
- Permissive hypercapnia
How do you check Auto Peep?
Expiratory hold at Zero PEEP
Consequences of Auto PEEP
Decreased Venous Return, impedance of expiration / spontaneous ventilations.
Maintain lowest possible FiO2 with all pts except:
Trauma & pregnant pts (less than 90% causes contractions)
