Ventilator Management Flashcards
(39 cards)
What 7 factors contribute to ventilation perfusion mismatch and intrapulmonary shunting in the early postop period?
Decreased Respiratory Drive following General anesthesia / mid sternotomy incision which produces Chestwall splinting / harvesting of the internal thoracic artery with plural entry / the effects of cardiopulmonary bypass / blood transfusion and potential for TRALI / pre-existing pulmonary comorbidities / phrenic nerve injury resulting in diaphragmatic dysfunction
What are the two principal mechanisms underlying poor gas exchange in the early postoperative period?
- Ventilation/perfusion (V/Q) mismatch
2. Intra-pulmonary shunting
Which ventilator mode reduces the use of analgesics and sedatives and often leads to a shorter duration of ventilator dependence?
BiPAP (beat out SIMV and A/C in trials)
What is the normal range for minute ventilation immediately postoperative?
100 mL/kg/min
How does immediate postoperative minute ventilation need to be changed for patients with COPD?
Lower respiratory rate, higher title volume, increased inspiratory flow rate (this reduces the risk for air trapping)
What preop factors predict A prolonged need for mechanical ventilation? (13 answers)
Presence of valvular disease / recent myocardial infarction / arterial hypertension / diabetes / previous cardiac surgery / chronic peripheral vascular disease / involvement of three or more vessels / surgical priority / elevated serum creatinine / age (>75 yo) / gender (female) / compromised LV function less than 40%EF / COPD
What are post operative predictors of the need for prolonged mechanical ventilation?
Hypoxia / decreased mentation / excessive intraoperative or post op bleeding / renal or cardiovascular failure / need for IABP / parenteral nutrition / inotropic therapy / acute respiratory distress syndrome (ARDS) / pulmonary edema / prolonged surgical or bypass time
Where is the respiratory center located in the brain?
Medulla oblongata
What branches of the nervous system control bronchial constriction and bronchial dilation?
Sympathetic = dilation Parasympathetic = constriction
What criteria can the ICU nurse use to determine patient readiness for ventilator weaning? (6 criteria)
General physiologic stability Hemodynamic stability Pulmonary mechanics Adequacy of gas exchange Ability to breed spontaneously Mental status
What are the factors in general patient physiologic and hemodynamic stability that influence the success of weaning from mechanical ventilation?
Presence of excessive bleeding Electrolyte imbalance: specifically phosphorus calcium magnesium and potassium Acid-base imbalance Volume overload Alterations in mental status Myocardial ischemia New onset dysrhythmia Need for vasopressors
What factors in pulmonary mechanics influence the success of ventilator weaning?
Vital capacity Minute ventilation Respiratory rate Tidal volume Negative inspiratory pressure
What are the two primary or underlying causes of failure to wean?
Failure of gas exchange at the alveolar level
Failure of ventilation
What are some potential patient outcomes from an acidotic pH level?
Decreased myocardial contractility
decreased vascular response to catecholamines and
decreased response to the effect and actions of certain medications
What are some potential patient outcomes from an alkaline pH level?
Interference with tissue oxygenation interference with normal neurologic function and normal muscular function
What are some common causes of respiratory acidosis in the postop cardiac surgery patient?
Poor muscle function from neuromuscular blocking agents
Pulmonary disorders such as atelectasis, pneumonia, pneumothorax, pulmonary edema or pulmonary embolism
Elevated CO2 from shivering or sepsis
Hypo ventilation caused by pain, sternal incision, residual anesthesia, impaired respiratory mechanics or opioid side effects
In appropriate ventilator settings
Hypo ventilation during bagging or transfer
What are some common causes of respiratory alkalosis in the postop cardiac surgery patient?
Hyperventilation from pain or anxiety
Increased demand for oxygen from fever or sepsis
Pulmonary edema or pneumonia
Medication causing respiratory stimulation
Inappropriate ventilator settings
Hyper ventilation during bagging or transfer
What are assessment signs of respiratory acidosis?
Warm flushed skin/bounding pulses/diaphoresis/tachycardia/dysrhythmias/central or peripheral cyanosis/pulmonary hypertension
What is the treatment for respiratory acidosis?
Treat the cause of the underlying hypo ventilation and increase ventilation
What are the assessment signs of respiratory alkalosis?
Lightheadedness dizziness agitation numbness or tingling in the extremities laryngospasm confusion blurred vision chest pain ischemic changes on the ECG peripheral vasoconstriction dysrhythmias and palpitations; dry mouth diaphoresis muscle twitching weakness tetanic spasm, some seizure
What is the treatment goal for respiratory alkalosis?
Treat the underlying cause, relieve muscle fatigue, prevent acute respiratory failure
What are some common causes of metabolic acidosis in the cardiac postop patient?
Decreased cardiac output/inadequate systemic perfusion/decreased cardiac function/decreased peripheral perfusion/hypotension/hypovolemia/vasoconstriction secondary to hypothermia/sepsis/renal failure/ischemia/diabetic ketoacidosis/anaerobic metabolism
What are the assessment signs of metabolic acidosis?
Headache/confusion/restlessness that progresses to lethargy/stupor/coma/Kussmaul respirations/cardiac dysrhythmias/decreased cardiac contractility with decreased cardiac output /hypotension/warm flushed skin/nausea and vomiting/insulin resistance/hyperkalemia
What is the single underlying treatment for metabolic acidosis?
Restore tissue perfusion thereby preventing further hypoxemia
