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Unit 2
RSPT-2314
Question | Answer |
---|---|
Adaptive Support Ventilation (ASV) | - Ventilator looks at the respiratory mechanics (& IBW) to determine the amount of support needed |
Mandatory Minute Volume (MMV) | - guarantees the delivery of a minimum (set) MV - If the patient’s spontaneous efforts do not meet the set minute volume, the ventilator will increase pressure, rate or volume to meet the set minute volume |
Volume Assured Pressure Support (VAPS) | - Pressure Support Ventilation (PSV) with a volume guarantee for each breath - Pressure Support (PS) level, tidal volume, respiratory rate and inspiratory flow are set - Patient initiates breath and at a minimum will get the set Vt at the set flow rate |
VAPS | - Breath is pressure supported as long as target tidal volume is met before set flow is reached - If Vt is not met before set flow is reached, breath switches to volume breath (Instead of pressure) to deliver remainder of tidal volume (Vt) |
Automatic Tube Compensation (ATC) | - compensates for the flow-dependent pressure decrease across the endotracheal tube during both inspiration and expiration. - reduces WOB and may improve patient comfort. - referred to as electronic Extubation. |
Volume Support Ventilation | PSV with a target tidal volume -Ventilator uses pressure supported breaths to deliver a target tidal volume PB 840 – SPONT mode, VS breath type -Set target volume, expiratory sensitivity and rise time % -PIP is limited by alarm setting |
Proportional Assist Ventilation (PAV) | - delivers a pressure assist in response to patient’s desired tidal volume and flow demands |
Neurally Adjusted Ventilatory Assist (NAVA) | - Responds to changes in diaphragmatic activity - Requires a specially designed nasogastric catheter with a 10-cm length of EMG electrodes |
NAVA primary indication | Primary indication would be a patient with a significant level of asynchrony |
Most important advantage to PAV and NAVA | - Improved synchrony |
Pressure Regulated Volume Control (PRVC) | -PCV with a targeted tidal volume -Ventilator uses pressure control breaths to deliver a target tidal volume -Inspiratory pressure varies breath to breath (< 3 cm H2O) to deliver target tidal volume |
PRVC | - Set RR, targeted tidal volume, PEEP, FIO2, IT (I:E, ET), rise time - Pressure limit is determined by high PIP alarm |
PRVC on an Evita XL | Autoflow (CMV or SIMV) |
PRVC on a Servo-I | PRVC |
PRVC on a PB 840 | VC+ (AC or SIMV) |
Ventilator Induced Lung Injury (VILI) | Complications Related to Pressure - Barotrauma Complications Related to Overdistention or inappropriate ventilation strategy - Volutrauma or Atelectrauma |
What happens with ventilator associated/induced lung injury? | -Increase in permeability of the A-C membrane -Pulmonary edema -Cell damage and necrosis -Diffuse alveolar damage -All a result of inappropriate ventilation strategy (too much pressure/volume or too little volume) |
Barotrauma | Physical injury sustained as a result of exposure to ambient pressures above normal, most commonly secondary to positive pressure ventilation (for example, pneumothorax and pneumomediastinum, pneumopericardium, and subcutaneous emphysema) |
Volutrauma | Alveolar overdistention and DAMAGE DUE TO ventilation with EXCESSIVE VOLUMES |
Atelectrauma (sheer forces) | Damage/injury to the lung due to repeated opening and closing of alveoli at lower lung volumes or inappropriate mechanical ventilation settings |
Time Constants | - The time necessary for passive inflation and deflation of the lung or lung unit is determined by the product of compliance and resistance - Must overcome critical opening pressure |
Time Constants (2) | - When Compliance or Resistance increase the time constant increases, when compliance or Resistance decrease the time constant decreases - Different lung units have different Time Constants |
Acute Hypoxic Respiratory Failure | - Hydrostatic (cardiogenic) - Non- hydrostatic (non-cardiogenic) |
Common Causes of Hydrostatic (Cardiogenic) Pulmonary Edema: Cardiac | -Left ventricular failure (e.g. myocardial infarction, myocarditis) -Cardiac valvular disease (aortic, mitral) |
Common Causes of Hydrostatic (Cardiogenic) Pulmonary Edema: Vascular | -Systemic hypertension -Pulmonary embolism |
Common Causes of Hydrostatic (Cardiogenic) Pulmonary Edema: Volume overload | -Excessive fluid administration -Renal failure -Hepatic failure |
Primary (Direct) Risk Factors for ALI and ARDS | -Direct Injury Pneumonia (viral, bacterial, fungal) Gastric aspiration Toxic inhalation (phosgene, cocaine, smoke, high concentration of oxygen) Near-drowning Lung contusion |
Secondary (Indirect) Risk Factors for ALI and ARDS | Indirect Sepsis and prolonged shock Burn injury (chemical or heat induced Multiple trauma Transfusions Pancreatitis Gynecologic (abruptio placentae, amniotic embolism eclampsia Drug effect (trans-retinoic acid for acute leukemia Sickle cell crisis |
Clinical Features of CHF/ARDS Features common to CHF and ARDS | -Symptoms of anxiety, dyspnea, tachypnea -Reduced lung volumes and decreased compliance -Hypoxemia (mild to severe), often requiring ventilator assistance -Chest radiograph shows diffuse alveolar and interstitial infiltrates |
Clinical Features of CHF/ARDS:Features Favoring CHF | Clinical history suggestive of CHF Symmetric pulmonary infiltrates Cardiomegaly or pleural effusions on chest radiograph PCWP > 18 mmHg Bronchoalveolar lavage fluid BALF: low protein level and noninflammatory Prompt <12 to 24 hours and lasting respons |