With following data, calculate pt Cs
PIP 48, Pplat 27, Vt 850, PEEP 4
Cs = Vt/Pplat - PEEP
.850/27-4 = 37 mL/cm H2O
A volume-cycled ventilator is in the control mode and the I:E ration alarm is sounding. The following control adjustment would correct this problem
Decrease the flow rate
Mechanical ventilation can lead to the following complications
decrease renal output
Barotrauma
decreased cardiac output
Static lung compliance will decrease as a result of the following
atelectasis
With the following data, calculate the desired rate to achieve a PaCO2 of 40
Vt 800, rate 15, FiO2 0.45
pH 7.50, PaCO2 30, PaO2 98
PaCO2 * Rate/40
30 * 15/40 = 11
The following data have been collected from a patient using a volume ventilator in the control mode.
Vt 700, rate 10, FiO2 50%, pH 7.44. PaCO2 42, PaO2 58. Based on this information, the RCP should recommend the following ventilator change
Increase FiO2 to 60%
With a PaCO2 of 42, pt is ventilating just fine. The PaO2 of 58 indicates pt is not oxygenating.
Pressure control ventilation is most commonly used for adults with what lung conditions?
ARDS
What effect does decreasing lung compliance have on a delivered Vt in a neonate receiving pressure-limited ventilation?
decreased Vt
What level of PS should be used for weaning so that airway resistance is overcome while breathing is spontaneous?
5-10 cmH2O - to overcome tubing resistance
As the oxygenation status of a patient worsens while on an O2 mask, at what point should CPAP be employed?
When FiO2 levels of 60% still result in hypoxemia
How is minute ventilation calculated?
Vt * Rate = Ve
How is alveolar minute ventilation calculated?
(Vt - anatomic Vd) * RR
Vd = 1ml/lb body weight
Calculate the ventilator tubing compliance when the volume is set at 200 ml (0.2 L) and an inspiratory pressure of 50 cmH2O is generated?
Volume/Pressure
200/50 = 4 mL/cmH2O
Calculate the corrected Vt when the patient is receiving a Vt of 700 ml with a PIP of 20 cmH2o and ventilator tubing compliance of 4 mL/cmH2O.
lost volume = (PIP * tubing compliance) - Vt
(20 * 4) - 700 = 620 mL
On the initial ventilator setup, at what range should the ventilator rate be set?
8-12 bpm
How should the appropriate ventilator Vt be determined
10-12 mL/kg
Indications for PEEP
atelectasis
hypoxemia with 60% FiO2
decreased FRC
lower O2 percentage to safe levels (< 60%)
decreased lung compliance
Pulmonary edema
Hazards of PEEP
Barotrauma
decreased venous return
decreased Cardiac output
decreased Urine output
Define optimal PEEP
The level of PEEP that improves lung compliance without decreasing cardiac output.
After the PEEP level is increased, how can it be determined the cardiac output has been adversely affected?
Decreased PvO2 levels and a drop in BP
How may the ventilator low-pressure alarm be activated?
leak in the vent circuit
leak around the chest tube
a ruptured ETT cuff
inadequate cuff pressure
patient disconnection
List ways the ventilator high-pressure alarm may be activated
decreased lung compliance
increase RAW due to: Airway secretions, bronshospasm, water in tubing, kink in vent tubing, patient coughing
How should the high-pressure alarm be set?
5-10 cmH2O above PIP
Factors that affect Raw
Bronchospasm
Water in the vent tubing
Mucosal edema
Secretions
Normal PETCO2
35-45 mmHg or 4.5-5.5%
Conditions that result in a decreased PETCO2
Hyperventilation
apnea
total airway obstruction
hypotension
pulmonary embolism
decreased cardiac output
Conditions that increase PETCO2
hypoventilation
hyperthermia
Indications for mechanical ventilation
VC = < 15 ml/kg
P(A-a)O2 > 450 mmHg on 100% FiO2
Vd/Vt > 60%
MIP < -20 cmH2O
PEP < 40 cmH2O
RR > 35 bpm
Complications of mechanical ventilation
Barotrauma = pneumothorax
Pulmonary infection
Atelectasis
Pulmonary O2 toxicity
Atelectasis
tracheal damage
decreased venous blood return
decreased urinary output
lack of nutrition
Cs equation
Cs= Vt/Pplat - PEEP
Conditions that result in decreased lung compliance
pneumonia
pulmonary edema
consolidation
atelectasis
air trapping
pleural effusion
pneumothorax
ARDS
What is indicated if PIP's are increasing but the Pplat is not increasing?
Raw is increasing
Ventilator weaning criteria
VC = > 15 mL/kg
Vt = 3 x's body weight (kg)
MIP > 20 cmH2O
Vd/Vt < 60%
A-a < 350 mmHg on 100% FiO2
RR < 25 bpm
Disease condition reversed
What RR are used with HFJV
100-600 cycles/min
Advantages of high-frequency ventilation over conventional ventilation
Reduced risk of barotrauma
Reduced risk of cardiac side effects
Less fluctuation in ICP
Improvement of mucociliary clearance
A ventilator patient receiving an FiO2 of 30% has a PaO2 of 60 mmHg. To increase the PaO2 to 80 mmHg, what change to the FiO2 must be made?
desired PaO2 * set FiO2/measured PaO2
80 * 0.30 / 60 = 40%
A patient on CMV with rate set at 8 lpm and PaCO2 of 55. To decrease PaCO2 to 40 mmHg. What changes must be made to the vent?
Rate * PaCo2 / desired PaCO2
8 * 55 / 40 = 11
A 36 y/o woman uses a ventilator in A/C mode with the following variables.
RR 10, Vt 650, FiO2 40%
ABG = pH 7.27, PaCO2 54, PaO2 75, HCO3 26
What vent alterations should be made?
increase Vt or RR to reduce PaCO2
A ventilator patient receiving a FiO2 of 70% and PEEP of 8 cmH2O has a PaO2 of 147 mmHg. What vent adjustment should be made to reduce PaO2
decrease FiO2 to < 60%
On a volume waveform is the tracing does not return to baseline, what does this indicate?
Leak in the tubing or around the ETT or chest tube; air trapping