ABGs, ARDS, and Mechanical Vent Flashcards
General Causes of Respiratory Failure
- Ventilatory Failure/Hypercapnia
2. Oxygenation Failure/Hypoxemic
Disorders Leading to Ventilatory Failure
- Impaired function of the CNS
- Neuromuscular dysfunction
- Musculoskeletal dysfunction
- Pulmonary dysfunction
What kind of CNS dysfunction can lead to ventilatory failure?
- Drug OD
- Head trauma
- Infection
- Sleep apnea
What kind of neuromuscular dysfunction can lead to ventilatory failure?
- Myasthenia gravis
- Gillian-Barre
- ALS
- Spinal cord trauma
What kind of musculoskeletal dysfunction can lead to ventilatory failure?
- Chest trauma
- Kyphoscoliosis
- Malnutrition
What kind of pulmonary dysfunction can lead to ventilatory failure?
- COPD
- Asthma
- Cystic fibrosis
- ARDS
What kind of disorders can lead to oxygenation failure?
- Pneumonia
- ARDS
- Pulmonary edema
- Hypoventilation
- Hypovolemic shock
- COPD
- Pulmonary embolism
- Restrictive lung diseases
Why can inadequate ventilation and respiratory failure occur postoperatively?
- Effects of anesthesia
- Pain medications
- Hurts to breathe
What is chronic respiratory failure?
Deterioration in the gas exchange function of the lung that has developed insidiously or has persisted for a long period after an episode of acute respiratory failure
Two causes of chronic respiratory failure
- COPD
2. Neuromuscular disease
Clinical Manifestations of Acute Respiratory Failure
- Restlessness
- Fatigue
- HA
- Dyspnea
- Air hunger
- Tachycardia
- Increased BP
Clinical Manifestations of Acute Respiratory Failure as it Progresses
- Confusion
- Lethargy
- Tachycardia
- Central cyanosis
- Use of accessory muscles
- Diaphoresis
- Respiratory arrest
Acute Respiratory Failure
Sudden and life-threatening deterioration of the gas exchange function of the lung. Failure of the lungs to provide adequate oxygenation or ventilation for the blood
Acute Respiratory Failure ABGs
- Decrease in PaO2 < 50 mm Hg (hypoxemia)
- Increase in PaCO2 > 50 mm Hg (hypercapnia)
- pH < 7.35; but always hypoxemic
Acute Respiratory Distress Syndrome (ARDS)
Occurs as a result of acute alveolar damage, inflammatory triggers release mediators, causing injury to alveolar and capillary membrane, as well as other structural damage to the lungs, severe ventilation-perfusion mismatch occurs, alveoli collapse, small airways are narrowed, resulting in severe hypoxemia. Blood is interfaced with nonfunctioning alveoli and gas exchange is markedly impaired (shunting)
- Typically develops over 4-48 hours
- Initially closely resembling severe hemodynamic pulmonary edema
Causes of ARDS
- Direct injury to the lungs (smoke inhalation, near drowning)
- Indirect injury to the lungs (shock, sepsis, pneumonia, overdose)
Clinical Manifestations of ARDS
- Rapid onset of severe dyspnea (12 to 48 hours after initiating event)
- Arterial hypoxemia (unresponsive to 100% O2)
- Sudden and progressive pulmonary edema (non-cardiac)
- Increasing bilateral dense infiltrates on chest x-ray (“ground glass”)
- Reduced lung compliance (stiff lungs)
- Intercoastal retrations
- Crackles
Diagnostics for ARDS
- BNP
- ECHO
- Pulmonary artery catheterization (Swan-Ganz) ** definitive method
ARDS Medical Management
- ID and treat underlying cause
- Intubation and mechanical ventilation (settings determined by status)(CMV or A/C w/PEEP)
- PEEP critical (improves oxygenation but not natural history of syndrome)
- Goal is PaO2 > 60 mm Hg or O2 sat > 90% at lowest possible FiO2
- Circulatory support, adequate fluid volume, nutritional support
- Inotropics or vasopressors
- PA line/Swan-Ganz/BNP/ECHO
- Nutritional therapy vital (enteral first consideration)
Pharmacologic Agents for ARDS
- Surfactant replacement
- Pulmonary antihypertensive agents
- Antisepsis agents
ARDS Nursing Management
- Suction PRN
- Positioning (prone)
- Turn frequently
- Reduce anxiety because it increases O2 demands
- Promote rest
- Assess nutritional status
- Document ventilator settings
What should be done if PEEP cannot be maintained?
Lots of sedation and possibly paralytics
Mechanical Ventilation
Provides warm body temperature 100% humidified O2 at levels 21-100%
Indications for Mechanical Ventilation
- PaO2 < 50 mm Hg with FiO2 > 0.60
- PaCO2 > 50 mm Hg with pH < 7.25
- RR > 35/min
- Peri-operatively
- Treatment of severe head injury
- Oxygenate when ventilation is inadequate
- To rest the respiratory muscles
Types of Mechanical Ventilation
- Negative pressure ventilators
2. Positive pressure ventilators
Negative Pressure Ventilators
- Exerts negative pressure on the external chest (iron lung, body wrap)
- Do not require intubation
- Requires a proper fit
- Contraindicated in unstable or complex patients
- Mainly used in chronic respiratory failure associated with neuromuscular conditions
Positive Pressure Ventilators
Exerts positive pressure forcing alveoli to expand during inspiration, expiration occurs passively (ET tube or tracheostomy)
Types of Positive Pressure Ventilators
- Pressure cycled vents
- Time cycled vents
- Volume cycled vents
- Noninvasive positive-pressure vents (NIPPV)
Pressure Cycled Vents
Delivers flow of air until it reaches a preset pressure, cycles off, passive expiration.
- Intermittent Positive Pressure Breathing (IPPB) also used to administer aerosolized meds
Time Cycles Vents
Used with newborns and infants, terminate or control inspiration after a preset time
Volume Cycled Vents
Most commonly used positive pressure ventilators, volume of air preset, vent cycles off, exhalation passive
Noninvasive Positive Pressure Vents (NIPPV)
Wears a mask
- CPAP
- Bi-PAP
Ventilator Modes
- Assist Control
- Intermittent Mandatory Ventilation (IMV)
- Synchronized Intermittent Mandatory Ventilation (SIMV)
- Pressure Support Ventilation (PSV)
- Positive End of Expiratory Pressure (PEEP)
- Continuous Positive Airway Pressure (CPAP)
Assist Control
- A/C or CMV
- Provides full support, tidal volume (VT), respiratory rate, FiO2
- Every breath gets full support, even if patient initiates a breath over set respiratory rate
- Used when they are 1st intubated or coming back from surgery
- Does everything for the patient
Intermittent Mandatory Ventilation (IMV)
Combination of mechanically assisted breaths (preset intervals) and spontaneous breaths (patient’s own tidal volume)
- Not used often
Synchronized Intermittent Mandatory Ventilation (SIMV)
Combination of mechanically assisted breaths (breaths per minute) and spontaneous breaths (patient’s own tidal volume)
- Regular and weaning modes
- Allows patient to breathe on their own a little
Pressure Support Ventilation
Applies pressure to the airway throughout the patient-triggered inspiration to decrease resistance within the tracheal tube and ventilator tubing
Positive End Expiratory Pressure (PEEP)
- Involves the maintenance of positive pressure at the end of expiration
- Holds the alveoli open, thus increasing gas exchange across the alveolar-capillary membrane
- Improves PO2 with lower concentrations of oxygen
- PEEP pressures range from 2.5-10 cm H2O
- PEEP increases intrathoracic pressure and cause hypotension and shock
- Not used alone, used with other ventilator modes
Types of Ventilator Alarms
- Volume
- Pressure
- Apnea alarm
Volume Alarms
Low Pressure Alarms
- Indicate low exhaled volume die to disconnection, cuff leak, and tube displacement
Pressure Alarms
High Pressure Alarms
- Indicate excess secretions, biting tube, kinks in tubing, coughing, pulmonary edema, bronchospasm, and pneumothorax
Apnea Alarms
Ventilator does not detect spontaneous respiration in a preset time period
Nursing Assessment for the Ventilator Patient
- All body systems and an in-depth respiratory assessment
- Any spontaneous effort
- Any evidence of hypoxia
- Adventitious breath sounds
- Evaluation of settings and functioning of ventilator
- Neurological status and effectiveness of coping
- Assess GI status and nutritional status
- I/O
- HOB 30-45 degrees
- Reposition ET tube Q24h
- Provide alternate method of communication
Potential Complications and Nursing Implications of Ventilator Patients
- Fluid retention
- Oxygen toxicity
- Hemodynamic compromise
- Risk for aspiration
- GI ulceration (stress ulcers)
- Ventilator acquired pneumonia (VAP)
- Barotrauma
Maintaining a Patent Airway with a Ventilator Patient
- Assess position and integrity of tube
- Document tube placement in cm at the teeth or lips
- Use two staff members for repositioning and re-securing tube
- Apply soft wrist restraints per hospital policy
- Use caution when moving client
- Suction oral and tracheal secretions
- Support ventilator tubing to prevent mucosal erosion and displacement
- Assess respiratory status every 1-2 hours
- Monitor and document ventilator settings hourly
- Suction and reposition client to promote mobility of secretions
Medications for Ventilator Patients
- Analgesics
- Sedatives
- Neuromuscular Blocking Agents
- Ulcer-Preventing Agents
- Antibiotics
- Corticosteroids
Analgesics Used for Ventilator Patients
- Morphine
2. Hydromorphone
Sedatives used for Ventilator Patients
- Lorazepam
- Midazolam
- Propofol
Neuromuscular Blocking Agent used for Ventilator Patients
Vecuronium bromide - give with pain meds and sedation
Ulcer Preventing Agents used for Ventilator Patients
- Pantoprazole
2. Famotidine
Signs of Weaning Intolerance
- RR > 30 or < 8
- BP or HR changes > 20% of baseline
- SaO2 < 90%
- Dysrhythmias, elevated ST segment
- Significant decrease in tidal volume
- Labored respirations, increased use of accessory muscles, diaphoresis
- Restlessness, anxiety, decreased LOC
Procedure for Extubation
- Explain
- Suction
- Deflate cuff
- Cough
- AFM observe for stridor, distress
Weaning
- Adequate psychological preparation
- A/C to SIMV to CPAP to T-piece
* May take hours, days, or weeks
* Temporarily withdraw sedation
Normal pH
7.35 - 7.45
Normal CO2
35 - 45
Normal HCO3
22 - 26
Causes of Metabolic Acidosis
- DM
- Shock
- Renal failure
Causes of Metabolic Alkalosis
- Volume depletion
- Vomiting
- NG output
- Diuretics
Causes of Respiratory Acidosis
- Pneumonia
- COPD
- Anesthesia
- Narcotics
Causes of Respiratory Alkalosis
Hyperventilation
