Term
| What is the primary clinical indication for using an iron lung? |
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Definition
| Generally, is indicated when a patient’s spontaneous breathing is no longer adequate to maintain life |
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Term
| What is volume cycled mechanical ventilation? |
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Definition
| The ventilator delivers a preset volume of gas with each breath. |
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Term
| What is pressure-controlled mechanical ventilation? |
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Definition
| The ventilator delivers a volume of gas until a preset pressure is reached. |
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Term
| What is Noninvasive Positive Pressure Ventilation (NIPPV)? |
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Definition
| The delivery of positive pressure ventilation via a tight-fitting mask that covers the nose or both the nose and mouth, has both Continuous Positive Airway Pressure (CPAP)and Bi-level Positive Airway Pressure (BIPAP). Can be used in out-patient setting sleep apnea (nasal CPAP) |
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Term
| What are the characteristics of Assist-Control Ventilation “AC”? |
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Definition
| Sensitized to the inspiratory effort of the patient, patient will always get the preset tidal volume or pressure, has minimum set rate. Overbreathing may be an issue |
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Term
| What are the characteristics of Controlled Mandatory Ventilation |
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Definition
| Ventilator provides a mechanical breath on a preset timing, ignoring patient effort, used for patients w/no spontaneous effort. Prolonged use may cause respiratory muscle atrophy |
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Term
| What are the characteristics of Synchronized Intermittent Mandatory Ventilation “SIMV”? |
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Definition
| Ventilator delivers a preset volume or pressure according to the set respiratory rate, only gives breath if patient does not breathe at a specific rate, used to wean patients from ventilators |
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Term
| What is Pressure Control Ventilation? |
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Definition
| A form of pressure assist, A/C and SIMV modes can be used. Maintains a set inspiratory effort though not a minimum rate (set by patient), positive pressure is used to augment spontaneous respiratory modes, must set apnea alarms when used alone |
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Term
| What is Continuous Positive Airway Pressure “CPAP”? |
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Definition
| Continuous level of elevated pressure is provided through the patient circuit, patient initiates all breathes but it decreases the work of breathing |
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Term
| What is Positive End-Expiratory Pressure “PEEP” ? |
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Definition
| PEEP is an airway pressure above atmospheric (i.e. positive) at the end of the ventilator cycle. Positive pressure applied to the end of the expiratory phase, prevents collapse of alveoli |
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Term
| What is the number 1 complication of mechanical ventilation? |
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Definition
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Term
| What risks increase barotrauma? |
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Definition
| Risk increases with higher tidal volumes, PEEP, PSV |
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Term
| How does barotrauma manifest? |
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Definition
| Manifestations may include pneumothorax, pneumomediastinum, Pneumoperitoneum, and air embolus |
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Term
| Up to 30% of patients on mechanical ventilation may die of what? |
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Definition
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Term
| What is the most common cause organism that appears in the first 4 days of using a mechanical ventilator? |
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Definition
| Staph aureus, though the gram-negative organisms that occur later most often lead to nosocomial pneumonia |
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Term
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Definition
| Inadvertent development of PEEP due to delivery of breath prior to completion of exhalation, can cause diminished cardiac output, hypotension, barotrauma |
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Term
| What causes electrolyte disturbances and arrhythmias when using an iron lung? |
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Definition
| Often due to changes in acid-base status, possible early indicator of pulmonary compromise or barotrauma |
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Term
| How does mechanical ventilation decrease cardiac output? |
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Definition
| High airway pressures which leads to high intra-thoracic pressures thus limiting venous return, decreases atrial filling |
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Term
| What causes oxygen toxicity when using mechanical ventilation? |
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Definition
| Most commonly occurs with prolonged delivery of FiO2 >.5, toxicity to proliferation of oxygen free radicals, possible retinopathy of prematurity in newborns, CNS may be effected |
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Term
| How should ventilators be calibrated? |
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Definition
| Too high a volume risks overinflation, too low a volume risks atelectasis, too high a rate risks inadequate expiratory time and autoPEEP, too low a rate risks inadequate minute ventilation and respiratory acidosis |
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Term
| How do you calculate idea tidal volume? |
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Definition
| Tidal volume of 10-12 ml/kg ideal body weight |
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Term
| Does paralysis equal sleep? |
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Definition
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Term
| How do you determine if a patient should be taken off mechanical ventilation? |
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Definition
| Occurs when precipitants of respiratory failure have been identified and eliminated, patient must also be stable. FI02 less than or equal to 0.5, PEEP less than or equal to 7.5 cm H20 |
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Term
| How do you evaluate patients on mechanical ventilation while weaning? |
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Definition
| Daily spontaneous breathing trial is performed using a T-piece or CPAP of 5 cm H20 |
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Term
| What are the 2 strategies for weaning off a mechanical ventilator following a failed attempt? |
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Definition
| 1. Spontaneous ventilation via T-piece for one hr. twice daily with full ventilatory support between trials on A/C. Length of T-tube trials progressively increased until patient no longer requires mechanical support, 2. Use of pressure support ventilation. SIMV mode with low resp. rate (6/min or less). Inspiratory pressure gradually decreased until patient can breathe spontaneously without ventilatory support |
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Term
| What characterizes acute lung injury? |
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Definition
| Increased permeability of the alveolar-capillary membrane. Alveolar spaces are flooded with edema fluid, proteinaceous material and cellular debris |
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Term
| What is the most severe form of acute lung injury? |
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Definition
| Acute Respiratory Distress Syndrome |
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Term
| Describe Acute Respiratory Distress Syndrome |
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Definition
| Represents the pulmonary manifestation of a systemic disorder that appears to trigger a dysregulated inflammatory response to injury. “Noncardiogenic pulmonary edema” |
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Term
| How is acute respiratory distress syndrome diagnosed? |
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Definition
PAO2/FiO2 (the ratio of the partial pressure of arterial oxygen to the fraction of oxygen in the inspired air.
ARDS:<200 ALI:<300 |
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Term
| What is the number 1 direct cause of acute respiratory distress syndrome? |
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Definition
| Acid aspiration or pneumonia |
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Term
| What is the number 1 indirect cause of acute respiratory distress syndrome? |
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Definition
| Sepsis (site of injury is vascular endothelium), trauma with prolonged hypovolemic shock |
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Term
| What is the hallmark characteristic of acute respiratory distress syndrome? |
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Definition
| Increased vascular permeability to proteins, leaving a hydrostatic gradient unopposed, so that any increase in capillary pressure will result in increases in interstitial and alveolar edema due to direct damage by inflammatory mediators such as cytokines, proteolytic enzymes, complement activators, and toxic oxygen metabolites |
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Term
| What are the clinical features of acute respiratory distress syndrome? |
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Definition
| Earliest clinical signs may be tachypnea and progressive hypoxemia associated with anxiety, in 24 hours, the patient becomes cyanotic, increasingly dyspneic, restless, and tachypneic |
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