Please enable JavaScript.
Coggle requires JavaScript to display documents.
Mechanical Ventilation (Complications of PPV (Alveolar Hypoventilation…
Mechanical Ventilation
Process by which fraction inspired oxygen (FIO2) at =>21% is moved into and out of lungs by a ventilator
Indications
Apnea or impending inability to breathe; Acute respiratory failure; Severe hypoxia; Respiratory muscle fatigue
Types
Negative Pressure Ventilation
Encases chest or body; Intermittent negative pressure pulls chest outward leads to air rushing in which leads to passive expiration; Similar to normal ventilation; Noninvasive ventilation that does not require an artificial airway
Positive Pressure Ventilation
Used primarily in acutely ill patients; Delivers air into lungs under positive pressure during inspiration that increased intrathoracic pressure during lung inflation (opposite of normal); Expiration occurs passively
Modes of PPV
Volume ventilation
Predetermined tidal volume (Vt) delivered with each inspiration; Amount of pressure needed to deliver each breath varies
Pressure Ventilation
Predetermined peak inspiratory pressure; Vt varies; Careful attention needed to prevent hyper/hypoventilation
Needs
Psychosocial
Agitation & Anxiety (Assess cause, Provide sedation and/or analgesia) Assess for delirium; Always address patients as if they are awake and alert
If necessary, induce paralysis to achieve more effective synchrony with ventilator and increase oxygenation; Paralyzed patient can hear, see, think, feel (sedation and analgesia must always be administered concurrently
Need to feel safe (Need to know, regain control, hope, trust) Encourage hope and built trust; Involve patients and caregivers in decision making
Assessment of paralyzed patient (Train-of-four TOF peripheral nerve stimulation; Physiologic signs of pain or anxiety; Ventilatory synchrony) Avoid excessive paralysis
Physical and emotional
stress
due to inability to speak, eat, move or breathe normally;
Pain, fear & anxiety
r/t tubes/machines; Ordinary ADLs are complicated or impossible
Nutrition
PPV and hyper metabolism leads to inadequate nutrition; Difficulty with oral intake (ET tube & Tracheostomy) Consult speech therapist for swallowing study
Nutritional assessment within 24-48 hours
Inadequate nutrition can decrease: O2 transport, Exercise tolerance, Serum protein, Weaning, Resistance to infection, Speed of recovery
Enteral gastric or small bowel feeding preferred; Verify tube placement (x-ray, exit site, aspirate) Limit CHO content lower to CO2 production
Settings
Pressure support; I:E ratio; Inspiratory flow rate and time; Sensitivity; High-pressure limit
Alarms
High-pressure limit; Low-pressure limit; High tidal volume, minute ventilation or respiratory rate; Low tidal volume or minute ventilation; Ventilator inoperative or low battery
Modes
based on how much work of breathing (WOB) patient should or can perform; Determined by patient's ventilatory status, respiratory drive & ABGs;
Controlled ventilatory support
Ventilatory does all the WOB
Assisted ventilatory support
Ventilator and patient share WOB
Pressure Modes/Ventilation
Assist-control (A/C) Ventilation
Delivers preset Vt at preset frequency; When patient initiates a spontaneous breath, preset Vt is delivered; Can breathe faster but not slower; Allows some control over ventilation; Risk for hypoventilation or hyperventilation; Continuous monitoring is required
Synchronized intermittent mandatory ventilation (SIMV)
Delivers preset Vt at preset frequency in synchrony with patient's spontaneous breathing; Between ventilator-delivered breaths, patient is able to breathe spontaneously
Patient receives preset FIO2 but self-regulates rate and volume of spontaneous breaths
Potential benefits
Improved patient-ventilator synchrony; Lower mean airway pressure; Prevention of muscle atrophy
Pressure support ventilation (PSV)
Postive pressure applied to airway only during inspiration in conjunction with spontaneous respirations; Machine senses spontaneous effort and supplies rapid flow of gas at initiation of breath; Patient determines inspiratory length, Vt and respiratory rate
Used for continuous ventilation and weaning
Advantages
Increase patient comfort; Decreased WOB; Decreased oxygen consumption; Increased endurance conditioning
Pressure-Controlled/inverse ratio ventilation (PC-IRV)
Combines pressure-limited ventilation with an inverse ration of inspiration to expiration;
Normal I/E is 1:2
; With IRV, I/E ration begins at 1:1 and may progress to 4:1
Progressively expands collapsed alveoli and has a PEEP-like effect;
Requires sedation with or without paralysis
; For
patients with ARDS and continuing refractory hypoxemia despite high levels of PEEP
Airway pressure release ventilation (ARPV)
Permits spontaneous breathing; Preset CPAP with short timed pressure releases; Vt varies;
Patients with ARDS who need high pressure levels
CPAP
Continuous positive airway pressure; Restores FRC (similar to PEEP); Pressure delivered continuously during spontaneous breathing
Used to treat obstructive sleep apnea; Administered non invasively by mask, ET or tracheal tube; Increase WOB: use with cation in patients with myocardial compromise
ATC
Automatic tube compensation; Used to overcome WOB associated with artificial airway; Increased during inspiration and decreased during expiration; Set by entering internal diameter of patient's airway and desired % of compensation
Bi-PAP
Bilevel positive airway pressure: Delivers oxygen and two levels of positive pressure support (Higher inspiratory positive airway pressure & Lower expiratory positive airway pressure
Noninvasive (Via tight-fitting face mask, nasal mask or nasal pillows); Patient must be able to breathe spontaneously and cooperate;
Indications; Contraindications
HFOV
High-frequency oscillatory ventilation; Delivery of a small Vt at rapid respiratory rates; Used for refractory hypoxemia and ARDS; Must sedate and paralyze patient
Complications of PPV
Alveolar Hypoventilation
Inappropriate ventilator settings; Leakage of air from ventilator tubing or around ET tube or tracheostomy cuff; Lung secretions or obstruction; Low ventilation/perfusion ratio
Rate or Vt set too high; Patients with COPD at risk (alkalosis develops if decrease PaCOs to standard normal); Determine cause if spontaneous hyperventilation
Ventilator Acquired Pneumonia
Occurs 48 hours or more after intubation!
Risk Factors
Contaminated respiratory equipment; Inadequate hand washing; Environmental factors; Impaired cough; Colonization of oropharynx
Guidelines to Prevent VAP
HOB elevation; No routine changes of ventilator circuit tubing; Continuous subglottic suctioning; Strict hand hygiene; Drain water from tubing
Volutrauma
Lung injury that occurs when large Vt are used to ventilate noncompliant lungs; Alveolar fractures and movement of fluids and proteins into alveolar spaces
Sodium and water imbalance
Progressive fluid retention
Decreased urinary output; Increased sodium retention
Etiology
Decreased CO; Intrathoracic pressure changes; Stress response
Pneumomediastinum
Rupture of alveoli into lung interstitum; Progressive air movement into mediastinum and subcutaneous neck tissue; Followed by pneumothorax
Neurologic system
Impaired venous drainage and increased cerebral volume which leads to increased ICP; Elevate HOB; Keep patient's head in alignment
Barotrauma
Air can escape into pleural space from alveoli or interstitial, accumulate, and becomes trapped pneumothorax; Patients with compliant lungs are at increased risk; Chest tubes may be placed prophylactically
GI System
Risk for stress ulcers & GI bleeding; Peptic ulcer prophylaxis (H2 receptor blockers, Proton pump inhibitors & Enteral nutrition)
Gastric and bowel dilation (NG or orogastric tube for decompression) Decreased peristalsis leads to constipation (Bowel Regimen)
Cardiovascular System
Increased Mean airway pressure transmitted to thoracic cavity leads to vessels compressed which leads to decreased venous return to heart (Decreased preload, Decreased cardiac output, Decreased blood pressure) PEEP increased effect
Musculoskeletal System
Loss of muscle strength and problems associated with immobility
Interventions to prevent
Adequate analgesia & nutrition; Early and progressive ambulation; Physical and occupational therapy
PEEP
Positive end-expiratory pressure; positive pressure applied to airway during exhalation, preventing alveolar collapse (increases lung volume and functional residual capacity (FRC) improves oxygenation
Maintain or improve oxygenation while limiting risk of O2 toxicity;
Contraindications
Patients with highly compliant lungs; Unilateral or nonuniform disease; Hypovolemia; Low cardiac output
Optimal or best PEEP
Peep titrated to point oxygenation improves without compromising hemodynamics
Physiologic PEEP= 5 cm H2O
Replaces glottic mechanism, helps maintain normal FRC and prevents alveolar collapse
Auto-PEEP
Result of inadequate exhalation time; Additional PEEP over what is set
Results
Increased WOB; Barotrauma; Hemodynamic instability
Interventions to limit auto-PEEP
Provide sedation and analgesia; Use large-diameter ET tube; Administer bronchodilators; Set short inspiratory times (Decreased respiratory rate: Decreased water accumulation in ventilatory tubing)
Nitric Oxide
Continuous inhaled NO leads to pulmonary vasodilation; Given via ET tube, tracheostomy or face mask;
Treat ARDS
;
Dx testing for pulmonary hypertension
; Cardiac surgery
Prone Positioning
Improves lung recruitment (Gravity reverses effects of fluid in dependent parts of lungs; Heart rests on sternum which leads to uniformity of pleural pressures) Nurse-intensive therapy
Extracorporeal Membrane Oxygenation (ECMO)
Alternative form of pulmonary support; Partially remove blood from patient, infuse O2, return blood back to patient; Intensive therapy
Machine Mishaps
Machine disconnection
Most frequent site for disconnection is between tracheal tube and adapter: ALWAYS KEEP ALARMS ON (if paused during suctioning or removal from ventilator, remember to reactivate before leaving.
Ventilator malfunction
May be due to power failure, failure of oxygen supply; If happens, disconnect patient from ventilator & manually ventilate with 100% O2
WEANING
Process of decreasing ventilator support & resuming spontaneous ventilation
Process differs for short-term versus long-term ventilated patients; Team approach; 3 Phases
Phases of Weaning
Weaning Process
Guidelines recommend a spontaneous breathing trail (SBT); SBT should be at least 30 minutes but not >120 minutes; May be done with CPAP, low levels of PSV or a T piece
Extubate if patient tolerates SBT; Return to ventilator if patient fails; Use weaning protocol; Important to rest between weaning trials; Provide explanations regarding weaning and ongoing psychological support
Comfortable position (siting or semirecumbent) ; Obtain baseline assessment (vital signs & respiratory parameters)
Weaning Outcome
Monitor for signs of intolerance: Tachypnea, Dyspnea, Tachycardia, Dysrhythmias, Sustained desaturation (SpO2 <91%) Hypertension or hypotension, Agitation or anxiety, Diaphoresis, Sustained Vt <5ml/kg, Changes in mentation
Weaning stops and patient is extubated or weaning is stopped because no further progress is made
Preweaning or assessment
Assess muscle strength
(negative inspiratory force); Assess endurance (
spontaneous Vt, vital capacity, minute ventilation and rapid shallow breathing index
); Auscultate lungs; Assess chest X-ray
Nonrespiratory Factors
Assessment of neurological status, hemodynamics, fluid & electrolytes/acid-base balance, nutrition and hemoglobin; Drugs should be titrated to achieve comfort but not excessive drowsiness
Extubation
Hyperoxygenate, Suction, Deflate cuff and remove tube at peak of deep inspiration; Encourage patient to deep breath and cough; Supplemental O2; Careful monitoring postextubation