Mechanical Vent Final Flashcards
Define PRVC
Volume targeted, pressure controlled breath. PRVC delivers breaths that are pt or time triggered, volume targeted and time cycled.
Define Permissive Hypercapnia
it is a deliberate limitation of the ventilator support to avoid lung over distention and lung injury
When would permissive hypercapnia be used?
-It is used when adequate ventilation cannot be maintained within acceptable limits for the pressure and volume. -Also used with ICP
A sudden rise in peak pressure can be caused by? How do you fix it?
-Cough: wait for pressure to drop to baseline and vitals to stabilize - Secretions: Suction - Low compliance: Switch to PC mode -Endobronchial intubation:Readjust or re-intubate -Pneumothorax: Aspirate the free air in the chest cavity -Increased System resistance: check for water, kinking or secretions -Bronchospasm: give a bronchodialator
Does a decrease set RR correct Respiratory Alkalosis?
Yes, it should help along w/ adjustments of tidal volume and a longer exhalation time for the I:E ratio
State the weaning parameter test w/ values:
-Negative inspiratory force: - 20 cmH2O -Pf Ratio: between 400-500 cmH2O (pf=pao2/fio2) -Cuff leak above 110cmH2O -PEEP level between 3-5 cmH2O -RSBI below 105 ( RSBI=f/Vt) -Vital Capacity: >15mL/kg (IBW) VC=IRV+ERV+Vt -Minute ventilation: <10-15 breaths/min (VE=Vt x f) -Tidal Volume >4-6L/min (Vt= f x Ti)
List the 5 requirements for ideal weaning index
1.Asses Pathological determinants of weaning outcome, ventilatory muscle function, pulmonary gas exchange (ventilation & oxygenation), as well as physiological problems 2. Accurately evaluate physiological functions as it relates to the abnormality present 3. Ease of measurements and reproducibility of measurements 4. Minimum pt cooperation 5. high positive and negative predictive values
What is the equation for RSBI?
RSBI=F/VT
How do you adjust ventilator settings for hypoventilation hypoxemia?
Change pt out of PS mode and into PC or VC –> If pt is in PS mode make sure nurse stopped sedatives Obtain an ABG –> Decrease FiO2 or increase depending on gas
How do you adjust ventilator settings for hyperventilation hypoxemia?
-Can be from a neuro pt -Use sedatives -Increase rate to somewhat match what pt is doing
What might cause a failed weaning trial?
Neurological factors -Nerve failure -Electrolyte disturbances -OSA is present but was overlooked Respiratory Factors Muscle weakness -Compliance and resistance issues -Increased deadspace -Impaired gas exchange Cardiovascular function -Increased metabolic demand with an increased WOB -Increase venous return with spontaneous ventilation Metabolic Factors and ventilatory muscle function -Hypoxic ventilatory response -Hypercapnic ventilatory response -Electrolyte imbalance -Severe hyperthyroidism Physiological Factors -Fear of loss of life support -Stress -Poor ambition -Loss of sleep
How do you correct for auto peep?
- Higher inspiratory flows, shortened inspiratory times, and longer exhalation times 2. Longer exhalation with smaller Tidal volumes and a decreases respiratory rate 3.Four modes of ventilation that may be used to decrease auto-PEEP in a patient who is intubated and has spontaneous breathing efforts. -IMV -PS -CPAP -APRV
What are the indications for PEEP Therapy?
-Bilateral infiltrates on radiograph -Recurrent atelectasis with low functional residual capacity -Reduced Lung Compliance -PaO2 < 60 mm mg -PaO2/FiO2 ratio <300 for ARDS -Refractory Hypoxemia
What are the determinants of optimal PEEP?
Optimal PEEP is the level of max beneficial effects of PEEP occur. There is an increase in oxygen transport, FRC, Cs and decrease in pulmonary shunting not associated with cardiopulmonary. Manipulating PEEP level to establish an optimal PEEP: increase the PEEP in increments of 5 cm H2O and remain at each level for 2-5 minutes. Monitor patient’s compliance. Then decrease PEEP progressively until compliance decreases. Point of decreased compliance of deflation represents the UIPd of the lungs. The lung can then be reinflated to reopen collapsed units. PEEP should be set 2-3 cm H2O above UIPd.
PEEP absolute contraindication in patients with?
PEEP absolute contraindication in patients with untreated pneumothorax. Not always beneficial to patients with emphysema because hyperinflation is present and may further distend the alveoli and lead to compression of the capillaries resulting in increased shunting/hypoxemia.
