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MV - Exam #1
Mechanical Ventilation Exam 1
Question | Answer |
---|---|
What are the four indications for mechanical ventilation? | Acute ventilatory failure, impending ventilatory failure, severe hypoxemia, prophylactic support |
What are the absolute contraindications for mechanical ventilation? | Untreated pneumothorax |
What are the relative contraindications for mechanical ventilation? | Patient's informed consent (DNR, DNI, family wishes/POA), medical futility, reduce or eliminate pain and suffering (terminal cases) |
What are the goals of mechanical ventilation? | Provide pulmonary system with support, maintain adequate ventilation, decrease WOB, restore acid/base balance, improve oxygenation, improve bronchial hygiene, avoid harmful side effects |
What is the most common reason to vent a patient? | Post-op patients |
What kind of nutritional support is needed for COPD patients? | COPD patients require higher caloric intake due to using all of their calories support breathing; COPD patients need 10x more calories than normal individuals |
What is sustained hyperventilation? | Used to reduce cerebral blood flow and therefore decrease ICPs, patient is hyperventilated to create RAK |
What is TPN? | Total Parenteral Nutrition, nutrition given through IV |
What are possible hepatic complications from mechanical ventilation? | Inversely (indirectly) related to amount of PEEP being applied, more PEEP = less liver function, pressure causes decreased perfusion to hepatic artery, decreased perfusion = decreased liver function |
What are the signs of hepatic complications? | Increased prothrombin time (blood doesn't clot as quicky; normal 12 - 15 seconds), increased bilirubin levels (jaundice), decreased albumin |
What mechanical ventilation settings effect hemodynamic values the most? | Level of airway pressures (PIP and MawP), tidal volume, PEEP |
What mechanical ventilation settings effect hemodynamic values the least? | Inspiratory flow rate, respiratory rate |
How does mechanical ventilation affect CVP? | Increased PVR = back up of blood from RV into RA; decreased C.O. = less venous return |
How does mechanical ventilation affect PCWP? | Not affected as much by PPV, unless using high PEEP, high PEEP will cause an increase in PCWP; body reabsorbs majority of back up fluids - edema in body |
How does mechanical ventilation affect aortic pressure and C.O.? | Increased pressure = decreased SV = decreased C.O. = decreased BP |
How is PAP effected by mechanical ventilation without PEEP? | Decreased SV due to decreased venous return, less blood pumping into pulmonary vessels, which lowers PAP and decreases CVP |
How is PAP effected by mechanical ventilation with PEEP? | Compresses pulmonary blood vessels significantly, increases PAP and CVP due to back up blood, constant pressure on lungs at all times, not just inspiration |
How are venous return and stroke volume affected by PPV? | Decrease preload, SV, and C.O., decrease renal function leading to fluid retention and decreased urine outpute, decreased venous return, increased ICP |
How can you decreased MawP? | By decreasing any of the factors that directly effect MawP; I-time, RR, PIP, PEEP, RAW |
What are possible complications of PPV? | Intubation complications, barotrauma/volutrauma, ventilator induced injury, oxygen toxicity, VAP, auto PEEP, cardiovascular effects |
How is hepatic perfusion effected by PEEP? | More PEEP = less liver function, pressure causes decreased perfusion to hepatic artery, decreased perfusion = decreased liver function |
What is normal urine output? | 1200-1500 cc/day (50-90 cc/hr) |
What is the 1st sign of decreased cardiac output? | Decreased urine output |
How much blood is needed to ensure that the kidneys can adequately remove waste? | 90 mL/min |
How does PEEP affect out of hemodynamic values? | Increased intrathoracic pressure, decreased venous return, decreased SV and CO, increased PAP, increased CVP |
How do you calculate deadspace? | VD/VT = PaCO2 - PeCO2 / PaCO2 (>20% gets a vent) |
What is the normal value for normal oxygenation? | 80 - 100 mmHg |
What is the normal value for mild hypoxemia? | 60 - 79 mmHg |
What is the normal value for moderate hypoxemia? | 40 - 59 mmHg |
What is the normal value for severe hypoxemia? | <39 mmHg |
What is oxygen failure (severe hypoxemia)? | aka "hypoxemia respiratory failure", PaO2 < 60 mmHg on >50% FiO2 or PaO2 <40 mmHg on any FiO2 - refractory hypoxemia |
What causes hypoxemic respiratory failure? | Diffusion impairment, intrapulmonary shunting, low V/Q ratio |
What are the four factors that affect RAW? | Viscosity of gas, velocity of gas, length of airway, diameter of airway |
What are causes of increased cL? | Improvement in problem, emphysema, position change, flail chest (no stability of rib cage) |
What are causes of decreased cL? | Atelectasis, pneumonia, pulmonary edema, ARDS, pneumothorax, pulmonary fibrosis, obesity, chest wall deformities (kyphosis) |
What are the four types of hypoxia? | Anemic, hypoxic, histotoxic, circulatory |
What is the equation for shunt? | QS/QT = CcO2 - CaO2 / CcO2 - CvO2 |
How do you calculate dynamic compliance? | VT / PIP - PEEP |
How do you calculate static compliance? | VT / Plat - PEEP |
What happens if a patient has increased cL and an increased E time? | Air trapping |