Weaning thr patient from the ventilator

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Weaning thr patient from the ventilator

• Dr. Aidah Abu Elsoud Alkaissi
• An-Najah National University
• Faculty of Nursing

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Respiratory Weaning

• The process of withdrawing the patient from
  dependence on the ventilator, takes place in
  three stages
• The patient is graually removed from the
  ventilator, then from the tube, and finally from
  oxygen
• The decision must be made from a physiologic
  rather than from a mechanical viewpoint
• A thorough understanding of the patients
  clinical status is required in making this
  decision
• Weaning is started when the patient is recovering
  from the acute stage of medical and surgical
  problems and when the cause of respiratory
  failure is sufficiently reveresed

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Respiratory Weaning

• Successful weaning involves collaboration among
  the physician, respiratory therapist, and nurse
• Each health care provider must understand the
  scope and function of pther team membersin
  reltion to patient weaning to conserve the
  patients strength use resources efficiently, and
  maximize successful outcomes

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Criteria for Weaning

• Careful assessment is required to determine
  whether the patient is ready to be removed from
  mechanical ventilation
• If the pat is stable and showing signs of
  improvement or reversal of the disease or
  condition that cause the need for mechanical
  ventilation, weaning incides should be assessed
• These incides include
• Vital capacity the amount of air expired after
  maximum inspiration. Used to assess the patients
  ability to take deep breaths. Vital capacity
  should be 10-15 ml/kg to meet the criteria for
  weaning
• Maximum inspiratory pressure (MIP) used to assess
  the patientss respiratory muscle strength. It is
  known as negative inspiratory pressure and should
  be at least 20 cm H2o
• Tidal volume volume of air that is inhaled or
  exhaled from the lungs during an effortless
  breath. It is normally 7-9 ml/kg
• Minute ventilation equal to the respiratory rate
  multiplied by tidal volume. Normal is about 6
  L/min
• Rapid/shallow breathing index used to assess the
  breathing pattern and is calculated by dividing
  the respiratory rate by tidal volume. Patient
  with indices bellow 100 breath/min/L are more
  likely to be successful at weaning

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Criteria for Weaning

• Other measurements used to assess readiness for
  weaning include a PaO2 of greater than 60 mm Hg
  with an FiO2 of less than 40
• Stable vital signs and arterial blood gases are
  important predictors of successful weaning
• Once readiness has been determined the nurse
  records baseline measurments of weaning indices
  (indication) to monitor progress

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Patient preparation

• Take into account factorsthat impair the delivery
  of oxygen and eliminationof carbon dioxide as
  well as those that icrease oxygen demand (sepsis,
  Seizures, thyroid imbalance) or decrease the
  patients overall stength (nutrition,
  neuromascular disease)
• Adequate psychological preparation is necessary
  before and during weaning processpatients need to
  know what is expected of them during the
  procedure
• They are often frightened by having to breathe on
  their own again and need reassurance that they
  are improving and are well enough to habdle
  spontanous breayhing
• The nurse explains what will happen during
  weaning and what role the patient will play in
  the procedure
• The nurse emphasizes that someonewill be with or
  near the patient at all times

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Methods of weaning

• Assist- control may be used as the resting mode
  for patients undergoing weaning trials
• This mode provides full ventilatory support by
  delivering a preset tidal volume and respiratory
  rate if the patient takes a breath, the
  ventilator delivers the preset volume
• The cycle does not adapt to the patients
  spontaneous efforts
• The nurse assesses patients being weaned on this
  mode for the following signs of distress rapid
  shallow breathing, use of accessory muscles,
  reduced level of consciousness, increase in
  carbon dioxide levels, decrease in oxgen
  saturations, and tachycardia

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Methods of weaning

• The patient on intermittent mandatory ventilation
  (IMV) can increase the respiratory rate, but each
  spontaneous breath receives only the tidal volume
  the patient generates, mechanical breaths are
  delivered at preset intervals and a preselected
  tidal volume, regardless of the patients efforts.
  IMV allows patient to use their own muscles of
  ventilation to help prevent muscle atrophy. IMV
  lowers mean airway pressure, which can assisi in
  preventing barotrauma

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Methods of weaning

• Synchronized intermittent nmandatory ventilation
  (SIMV) deliver a preset tidal volume and number
  of breath per minute
• Between ventilator delivered breaths, the patient
  can breathe spontaneously with no assistance from
  the ventilator on those extra breaths
• As the patiens ability to breath spontaneously
  increases, the present number of ventilator
  breaths is decreased and the patient does more of
  the work of breathing
• SIMV is indicated if the patient satisfies all
  the criteria for weaning but cannot sustain
  adequate spontaneous ventilation for long periods
• IMV and SIMV can be used to provide full or
  partial ventilatory support
• Nursing intervention for both of these include
  monitoring progress by recording respiratory
  rate, minute volume, spontaneous and
  machine-gnrated tidal volume, FiO2, and arterial
  blood gas level.

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Methods of weaning

• The pressure support ventilation (PSV) mode
  assist SIMV by applying a pressure platea to the
  airway throughout the patient triggered
  inspiration to decrease resistanceby the tracheal
  tube and ventilator tubing
• Pressure support is reduced gradually as the
  patients strength increases
• A SIMV back up rate may be added for extra
  support
• The nurse must closely observe the patients
  respiratory rate and tidal volumes on intiation
  of PVS it may be necessary to adjust the pressure
  support to avoid tachypnea or large tidal volume

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Methods of weaning

• The continous positive airway pressure (CPAP)
  modes allows the patient to breathe
  spontaneously, while applying positive pressure
  throughout the respiratory cycle to keep the
  alveoli open and promote oxygenation
• Providing CPAP during spontaneous breathing also
  offers the advantage of an alarm system and may
  reduce patient anxiety if the patient has been
  taught that the machine is keeping track of
  breathing
• It also maintains lung volumes and improves the
  patients oxygenation status.
• CPAP is often used in conjunction with PVS
• Nurses should carefully assess for tachypnea,
  tachycardia, reduced tidal volumes, decreasing
  oxygen saturation and increasing carbon dioxide
  levels

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Methods of weaning

• Weaning trials using a T-piece or tracheostomy
  mask are normally conducted wwith the patient
  disconnected from the ventilator, receiving
  humidified oxygen only and performing all work of
  breathing
• Patient who do not have to overcome the
  resistance of the ventilator may find this mode
  more comfortable or they become anxious as they
  breathe with no support from the ventilator
• During T-piece trial the nurse monitors the
  patint closely and provides encouragement
• This method of weaning is used when the patient
  is awake and alert, is breathing without
  difficulty, has good gag and cough reflexes and
  is hymodynamically stable
• During the weaning process, the patient is
  maintained on the same or a higher oxygen
  concentration than when on the ventilator
• When on the T-piece , the patient should be
  observed for signs and symptoms of hypoxia,
  increasing respiratory muscle fatigue, or
  systemic fatigue

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Methods of weaning

• These include restlessness, increased respiratory
  rate greater than 35 breath/ min, use of
  accessory muscles, tachycardia with prmature
  ventricular contractions and a paradoxical chest
  movement (asynchronous breathing, chest
  contraction during inspiration and expansion
  during expiration)
• Fatigue or exhaustion is initially manifested by
  an increased respiratory rate associated with a
  gradual reduction in tidal volume, later there is
  a slowing of the respiratory rate
• The patient is placed back on the ventilator each
  time signs of fatigue or deterioration developmet
• If clinically stable, pat can extubated within
  2-3 hours of weaning and allowed spontaneous
  ventilation
• Pat who have had prolonges ventilatory assistance
  usually require more gradual weaning. It may
  taked dayr or even weeks
• They ae weaned primarily during the day and
  placed back on the ventilator at night to rest

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Methods of weaning

• Successfull weaning is supplemented by intensive
  pulmonary care, the following are continued
• Oxygen therapy
• Arterial blood gas evaluation
• Pulse oximetry
• Bronchdilator therapy
• Chest physiotherapy
• Adequate nutrition hydragen, and humidification
• Incentive spirometry