Respiratory Failure

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Respiratory Failure Vents

• N2205
• Spring 2002
• Becca Maddox

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Respiratory Failure

• Definition - Exchange of CO2 for O2 cant keep up
  with O2 consumption and CO2 production in the
  cells of the body.
• PaO2 lt 50 mmHg
• PaCO2 gt 45 mmHg
• Acute vs. Acute Exacerbation of Chronic
  Respiratory Failure
• Principles of Management are different
• Acute - lungs normal prior to illness and return
  to normal
• Chronic - structural damage is irreversible

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Acute Respiratory Failure

• Causes of Inadequate Ventilation and/or Perfusion
• Central Nervous System Depression
• (Drug overdose, head injury, stroke, brain
  tumors, anesthesia, opioids, meningitis,
  encephalitis, hypoxia, hypercapnia)
• Primary Neurologic Disorders
• (Guillian-Barre syndrome, myasthenia gravis,
  multiple sclerosis, cervical spinal cord injury)
• Acute Lung Diseases
• (pneumonia, pneumonitis, asthma, atalectasis,
  pulmonary embolus, pulmonary edema)
• Thoracic or Abdominal Surgery/Trauma

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Adult Respiratory Distress Syndrome(a.k.a
Noncardiogenic Pulmonary Edema)

• Results from injury of the alveolar capillary
  membrane causing leakage of fluid into the
  interstitial spaces of the alveoli
• Results in V/Q mismatch
• Decrease in surfactant production causes alveoli
  to collapse
• Lungs become stiff - functional residual capacity
  decreases
• Mortality rate is 50-60
• Best chance of survival - early detection,
  identification of cause and aggressive treatment

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• Diagnostic Criteria
• Acute Respiratory Failure
• Bilateral fluffy infiltrates
• PaO2 lt50-60 mmHg (despite high FiO2)
• Treatment
• ID and treat the cause
• Assure adequate ventilation
• Provide circulatory support
• Ensure adequate fluid volume
• Provide nutritional support (35-45 kcal/kg/day)

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• Terms to be familiar with
• PaO2 - partial pressure of oxygen in arterial
  blood
• PaCO2 - partial pressure of carbon dioxide in
  arterial blood
• FiO2 - fraction of inspired oxygen ()
• PEEP - Positive end-expiratory pressure
• CPAP - continuous positive air pressure
• FRC - functional residual capacity
• V/Q - Ventilation-Perfusion

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Nursing Interventions

• Frequent assessment of respiratory status is
  important because acute respiratory failure and
  ARDS can quickly become life-threatening
• Place in semi-Fowlers or high-Fowlers position
  to facilitate expansion of lungs
• Encourage fluids unless restricted - loosens
  secretions, replaces fluid loss from rapid
  respiratory rate
• Reduce oxygen demands
• Reduce anxiety - anxiety increases oxygen
  consumption

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• Provide respiratory care as ordered (oxygen,
  nebulizers, incentive spirometer, chest PT,
  suctioning, ventilator management)

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Review of Respiratory Care Modalities

• Oxygen Therapy
• used to raise patients PaO2 back to baseline
  (60-95 mmHg)
• avoid excessive oxygen (toxicity, depress
  ventilation in COPD patients)
• oxygen toxicity can occur when FiO2 gt 50 for
  longer than 48 hours
• Nasal cannula - do not exceed 6L/m, if 6L/min is
  required you should consider facemask
• Facemasks - deliver 40-100 depending on type

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Respiratory modalities contd

• IPPB - patient initiates a breath and the machine
  forces a preset breath
• Not used much any more related to complications -
  pneumothorax, increased ICP, gastric distention,
  vomiting and aspiration
• Nebulizer - patient inhales a mist of microscopic
  particles (saline or medication)
• Incentive Spirometer - guides the patient in
  taking slow, deep breaths to maximize inflation
• CPT - postural drainage, percussion therapy, deep
  breathing and coughing

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Endotracheal Intubation

• Provides an airway for mechanical ventilation and
  suctioning
• An endotracheal tube is passed through either the
  nose or the mouth into the trachea
• Once the tube is in place, a cuff is inflated to
  prevent air from leaking, minimize the risk of
  aspiration, and prevent movement of the tube
• An intubated patient cannot speak
• Not for long-term airway management

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• Procedure
• Equipment - endotracheal tube, laryngoscope,
  stylet, water soluble lubricant, syringe
• Insert stylet into ET tube
• Tilt head back
• Insert laryngoscope and gently lift up avoiding
  pressure on teeth
• Visualize vocal cords
• Pass ET tube through vocal cords
• Inflate cuff
• Assess chest wall movement and breath sounds
• Obtain chest x-ray

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• Complications
• Irritation and/or trauma to tracheal lining
• Vocal cord paralysis
• Nosocomial Infections
• Disadvantages
• Discomfort
• Cough reflex depressed
• Secretions become thicker
• Swallowing reflexes are depressed

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• Suctioning
• Equipment - suction catheter (in-line,
  cath-n-glove), saline, ambu bag, saline solution
• Procedure -
• hyperventilate patient
• insert catheter through ET tube into lungs far
  enough to stimulate a cough
• as patient coughs, withdraw catheter with a
  twisting motion while applying suction - do not
  exceed 10 secs
• reoxygenate the patient
• may need saline to thin secretions and elicit
  cough

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Mechanical Ventilation

• Indications
• PaO2 lt 50 mmHg with FiO2 gt .60 (60)
• PaO2 gt 50 mmHg with pH lt 7.25
• Vital capacity lt 2 times tidal volume
• Negative inspiratory force lt 25 cmH2O
• Respiratory rate gt 35/min
• Apnea

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Types of Ventilators

• Negative-Pressure Ventilators -
• External vents - do not require intubation
• Create negative pressure on the chest thus
  allowing air to flow into the lungs
• Used mostly for chronic respiratory failure in
  patients with neuromuscular diseases
• Iron Lung, Pneumowrap, Tortoise Shell

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Types of Ventilators

• Positive Pressure Ventilators (most common)
• Pressure-cycled - Delivers flow of air until a
  preset pressure is reached (IPPB)
• - inconsistent tidal volume
• - for short-term use only
• Time-cycled - volume is controlled by time of
  inspiration and flow of air
• Volume-cycled (most common) - flow of air is
  delivered until a set tidal volume is reached
• - consistent breath can be delivered despite
  varying airway pressures

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Features and Settings

• Tidal Volume - The volume of breath to be
  delivered (10-15 ml/kg body weight)
• FiO2 dependent on patient need, evaluated by PaO2
  on ABG
• Respiratory Rate - usually 12-16
• Sensitivity - the pressure level that the patient
  has to generate to trigger the ventilator
• Type of Ventilation - controlled, assist/control,
  intermittent mandatory ventilation (IMV)
• Sigh - used with assist/control only. Volume is
  1.5 time TV. Usually 1-3/hr.

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Features and Settings contd

• PEEP (positive end-expiratory pressure) -
  pressure maintained at end of expiration to keep
  alveoli open
• Physiological PEEP - 3 to 5 cmH2O
• Minute Volume- the amount of air inspired in one
  minute (TV x RR)
• Airway Pressure - the amount of pressure
  necessary for ventilator to deliver the breath
  (15 to 20 cm H2O)

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Care of the Ventilated Patient

• Assessment - assess patient status and
  functioning of ventilator
• Vital signs, evidence of hypoxia (restlessness,
  anxiety, tachycardia, increased respiratory rate,
  cyanosis), respiratory rate and pattern, breath
  sounds, neurologic status, TV, MV, forced vital
  capacity, suctioning needs, spontaneous
  ventilatory effort, nutritional status,
  psychologic status
• Type of ventilator, mode, TV and rate settings,
  FiO2, Inspiratory pressure and pressure limit,
  sigh settings, tubing, humidifier, alarms, PEEP

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Care contd

• IMPORTANT - if you ever think the ventilator is
  not fuctioning properly and it cannot be
  identified and corrected immediately, disconnect
  the patient from the vent and manually ventilate
  the patient with an Ambu bag!!!

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Care contd

• Diagnosis -
• Impaired gas exchange
• Ineffective airway clearance
• Risk for trauma and infection
• Impaired physical mobility
• Impaired verbal communication
• Ineffective individual coping and powerlessness

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Care contd

• Collaborative Problems/Potential Complications
• Fighting (bucking) the ventilator
• Ventilator problems (increased peak airway
  pressure, decrease in pressure, loss of volume)
• Cardiovascular compromise
• Barotrauma and pneumothorax
• Pulmonary infection

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Care contd

• Planning and Implementation
• Goals -
• promote optimal gas exchange
• pain relief, positioning, monitor fluid balance,
  administer meds to treat underlying disease,
  auscultate lungs, monitor ABGs and O2
  Saturation, chest PT, suction
• reduce mucus accumulation
• auscultation, chest PT, suction, positioning,
  increase mobility as soon as possible,
  humidification, bronchodilators

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Care contd

• Planning and Implementation
• prevent trauma or infection
• proper positioning of ET tube, maintain cuff
  pressure, oral care, trach care, aspiration
  precautions
• obtain optimal mobility
• OOB into chair as soon as possible, ROM exercises
• adjust to non-verbal communication
• assess patients abilities (physical and mental),
  be creative

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Care contd

• Planning and Implementation
• acquire successful coping mechanisms
• assist to verbalize feelings, explain procedures,
  allow participation when possible, supply
  diversions, provide stress reduction strategies
• Evaluation - were goals met? If not, why not?

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Problems with Mechanical Ventilation

• Ventilator Problems
• Increase in peak airway pressure
• coughing or plugged airway tube, patient
  bucking the ventilator, decreasing lung
  compliance, kinked tubing, pneumothorax,
  atalectasis or bronchospasm
• Decrease in pressure or loss of volume
• increase in compliance, leak in ventilator or
  tubing, cuff leak, loose connection

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Problems with Mechanical Ventilation

• Patient problems
• Cardiovascular compromise
• decrease in venous return due to positive
  pressure vent
• Barotrauma/Pneumothorax
• positive pressure ventilation, high mean airway
  pressures can lead to alveolar rupture
• Pulmonary Infection
• bypassing of normal barriers, frequent breaks in
  circuit, decreased mobility, impaired cough reflex

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Neuromuscular Blocking Agents

• Muscle relaxants, tranquilizers, analgesics and
  paralyzing agents are given to increase
  patient-machine synchrony by decreasing
• anxiety
• hyperventilation
• excessive muscle activity (increasing O2 demand)
• Paralyzing agents are used as a last resort
• Most common agents used are
• pancuronium (Pavulon)
• vercuronium (Norcuron)
• atracurium (Tracrium)

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Neuromuscular Blocking Agents contd

• Read about all three in Lippincotts Drug Guide
• With each, patient receives a loading dose and
  then paralysis is maintained either with
  intermittent boluses or constant IV infusion
• Pancuronium is considered the drug of choice for
  long-term neuromuscular blockage
• Loading dose of 40-100 mcg/kg followed by doses
  of 10 mcg/kg every 20-60 minutes as needed.
• NMB drugs only cause paralysis. Patient must have
  sedatives or analgesics also.

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Neuromuscular Blocking Agents contd

• Monitor vital signs - can cause tachycardia and
  hypotension
• Monitor respirations, ventilator and settings,
  any respiratory effort
• Monitor neuro status - nerve stimulation
  (train-of-four) q2hrs, stop paralysis at least
  once daily to assess underlying neuro status (and
  to evaluate continued need for paralysis)
• With long-term use, skeletal muscle weakness and
  disuse atrophy occur. Recovery can take weeks to
  months.

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Weaning the Patient from the Ventilator

• Weaning should begin as soon as possible
• Weaning begins when the patient is recovering
  from the acute stage and cause of failure has
  been sufficiently reversed.
• Criteria
• Can take good deep breaths ( TV approx. 1000cc,
  min. volume 10 to 15 ml/kg, spontaneous
  inspiratory force of at least -20cm H2O)
• PaO2 gt 60 with FiO2 40
• Stable vital signs
• Patient readiness

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Weaning Methods

• With any weaning method, observe the patient for
  signs and symptoms of hypoxemia or fatigue
• tachycardia
• PVCs, ischemic EKG changes
• blood pressure or heart rate changes
• restlessness, diaphoresis, decreasing level of
  consciousness
• resp. rate gt 35, use of accessory muscles,
  paradoxical chest movement
• increasing PaCO2 and/or decreasing pH,
  decreasing O2sat

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Weaning Methods contd

• T-piece trials - use only when patient has been
  on the vent a short time
• place on t-bar, monitor patient, obtain ABG in 20
  minutes
• if tolerates t-bar for for 2-3 hours, can
  extubate and place on facemask (usually at same
  FiO2)
• IMV - amount of support provided by the
  ventilator is gradually reduced and work of
  breathing by the patient is increased
• May take several hours or several days
• Rate of wean is determined by ABGs and patient
  assessment

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Home Ventilators

• Review Charts 25-5 and 25-6
• Interventions related to preparing a patient to
  go home with a vent
• Patient/family teaching re care of the
  ventilator, suctioning, trach care, S/S of
  pulmonary infection, cuff inflation and
  deflation, vital signs
• Work with physician, respiratory therapy, social
  services, home health agency and equipment
  supplier to make sure patient and family are
  ready for the move
• Nurses have a responsibility to evaluate patient
  and family understanding of information given

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• Family must have a plan for emergencies such as
  ventilator malfunction, power outages,
  transportation
• Family must know how to perform CPR including
  mouth-to-trach breathing