Weaning/HS (nurse)

This article is intended for students of secondary and higher vocational schools of nursing.

Explanation of terms

 * Weaning – weaning, weaning.
 * Discontinuation – termination, disconnection.
 * Successful disconnection – disconnection from the ventilator and spontaneous ventilation for at least 48 hours without the need for ventilatory support.
 * Successful extubation/decannulation.
 * Disconnection failure – necessity to restart the patient's UPV after previous disconnection within 48-72 hours of spontaneous ventilation.
 * On average in about 20% of patients, in patients with CNS impairment up to 33%.
 * Simple disconnection – the patient tolerates the first SBT and is successfully extubated – 70% of patients.
 * Difficulty Weaning – First Spontaneous Breathing Trial (SBT) failed, 2-3 SBTs required for successful weaning or within 7 days of first SBT.
 * Prolonged disconnection - Failed at least 3 SBTs or lasted more than 7 days since the first SBT.
 * Spontaneous Breathing Trial (SBT) - Spontaneous breathing on low pressure support (5-7 cm H 2 O)/ATC or Ayer 'T' at FiO 2 0.5.
 * Closer monitoring is needed for the first few minutes → most problems occur during this period.
 * The test lasts a minimum of 30 minutes, but no more than 120 minutes.

Method
It is necessary to consider the termination of ventilation support from the moment of its initiation!
 * 1) Income.
 * 2) Treatment of respiratory failure.
 * 3) Readiness for disconnection.
 * 4) Unplugging.
 * 5) SBT.
 * 6) Extubation.
 * 7) Release.


 * Switch to a mode with elements of spontaneous ventilation as soon as possible.
 * Support of spontaneous breathing activity (outside the critical phase).
 * Test the ability to breathe spontaneously.
 * Elimination/reduction of sedation.
 * Guidelines – protocol of the department.
 * Type of patients, experience, ventilator types, nurse/patient ratio.

Approaches

 * 1) Clinical approach - physician-directed approach.
 * 2) * The attending physician assesses the patient's condition and decides on the initiation of disconnection and the method of disconnection.
 * 3) Protocol (nurse) driven approach.
 * 4) * The procedure established by the protocol.
 * 5) * Routine disconnection "readiness" screening:
 * 6) ** Nurse, respiratory technician, resident;
 * 7) ** part of the office of the responsible doctor.

Ayer's T

 * Minimum resistance.
 * Excellent tolerance test - 30'-120'.
 * Absence of ventilator monitoring.
 * Absence of backup ventilation.
 * The need for supervision.
 * Very fast transition to spontaneous breathing.

Weaning via ASB

 * The patient regulates f, Vi and VT himself.
 * Fan synchronization, WOB reduction.
 * PEEPint compensation in COPD (COPD).
 * Optimal f 25–30/m.
 * Unsuitable unstable respiratory drive.
 * Tachypnea (autoPEEP).
 * Auto-trigger (leak).
 * Apnoeic pauses during excessive inspiratory pressure!!!

Risks of extending UPV

 * Infection (VAP).
 * UPV lung damage.
 * Need for sedation.
 * Respiratory tract injury.
 * Costs.

Risks of premature termination of UPV

 * Loss of control of airway patency.
 * Cardiovascular stress - circulatory failure.
 * Insufficient gas exchange.
 * Excessive strain and fatigue of respiratory muscles.

Reintubation

 * Reintubation is an independent risk factor for the development of nosocomial pneumonia and higher mortality.
 * Internal and neurological patients → longer hospitalization, more frequent tracheostomy, higher mortality.
 * Positive fluid balance.
 * Positive culture of tracheobronchial secretions in patients with COPD within 72h after extubation.
 * Amount of sputum - suction > 2 x hour, sputum > 2.5 ml/h.
 * Tidal volumes – Vt >4–5 ml/kg, df < 30/min.

Cause of disconnection failure

 * Respiratory tract: Aspiration (gastric nutrition, suction NG body position), secretion in the respiratory tract, swelling of the respiratory tract.
 * Outside the respiratory tract: Respiratory insufficiency due to other causes, cardiac failure, impaired consciousness, uncooperative patient.

Failure factors

 * Decreased activity of the respiratory center: Lack of sleep, general fatigue, encephalopathy of various etiology, excessive sedation, metabolic alkalosis (compensation of chronic RAC).
 * Increased work of breathing: Hyperventilation - CNS damage, increased dead space ventilation, withdrawal syndrome; difficult expiration – PEEPi,airway obstruction, COPD; inappropriate ventilation mode; increased production of CO 2 – increased intake of energy (sugars), hypermetabolism, hyperthermia; raised diaphragm – high intra-abdominal pressure.
 * Central and peripheral nervous system - ventilatory failure.
 * Respiratory system: Oxygenation failure - cause at the level of blood gas exchange through the alveolocapillary membrane (pneumonia, fibrosis,...); ventilation failure – malfunction of the ventilation pump.
 * Cardiovascular system: Changes in intrathoracic pressure during disconnection; increased respiratory muscle demands; heart failure; imbalance between the supply and consumption of oxygen by the myocardium - myocardial ischemia.
 * Psychological cause.
 * Weakness and fatigue of respiratory muscles.
 * Malnutrition, respiratory muscle catabolism.
 * Muscular atrophy, neuromyopathy of critically ill patients.
 * Mineral breakdown (hypophosphatemia, hypomagnesemia).
 * Muscle ischemia during excessive exercise.
 * Paresis of the phrenic nerve.
 * Polyneuritis, myasthenia.
 * muscle relaxation.

Clinical monitoring

 * Subjective shortness of breath.
 * Involvement of auxiliary respiratory muscles.
 * Perspiration.
 * Tachycardia.
 * Abdominal paradoxical breathing.
 * Subjective discomfort.

Disconnect criteria

 * 1) Adequate oxygenation (more permissive).
 * 2) * PaO 2 /FiO 2 > 150 to 200 mm Hg; PEEP < 5–8 cm H 2 O; FiO 2 < 0.4 to 0.5; pH > 7.25.
 * 3) Hemodynamic stability.
 * 4) * Absence of acute myocardial ischemia.
 * 5) * Absence of significant hypotension (0/ or only low-dose dopamine / dobutamine <5μg/kg/min), heart rate <140/min.
 * 6) Improvement of clinical condition.
 * 7) * Afebrile < 38 °C, no RAc and Ral, Hgb 80–100 g/l, GCS > 13, no continuous sedation, stable metabolic conditions (electrolytes).

Prerequisites for successful extubation

 * Airway patency.
 * Reflexes of the cranial nerves (coughing, swallowing, expectoration).
 * Absence of excessive secretion from the respiratory tract.
 * Consciousness (minimizing sedation, responding to challenge).
 * No risk of post-extubation stridor.
 * Test for determining the risk of post-extubation airway obstruction (air leakage around the deflated cuff of the tracheal tube).

SBT failure procedure

 * Connection to a ventilator (adequate ventilation support),
 * The need to identify the cause of the failure.
 * Repetition of SBT is recommended no earlier than in 24 hours, performing several times a day is not demonstrably associated with shortening the duration of ventilatory support.
 * In selected situations where SBT fails due to a quickly correctable cause, it is considered to repeat it earlier.
 * Gradual reduction of ventilatory support.

Disconnection tolerance criteria

 * RR > 35/min, SpO 2 < 88%, PaO 2 60 mmHg, VT below 4 ml/kg.
 * Tachycardia.
 * Lower values ​​can be tolerated for a maximum of minutes.
 * Signs of respiratory distress (at least 2):
 * significant involvement of auxiliary respiratory muscles;
 * paradoxical abdominal breathing;
 * perspiration;
 * subjective feeling of dyspnea.
 * subjective feeling of dyspnea.

Patients who are difficult to detach

 * Failure after 14-21 days of repeated attempts.
 * Irreversible addiction (neurological dg.1–5%).
 * High spinal cord lesion, ALS,...


 * Freight patients.
 * Higher morbidity & mortality (only 25% discharge).
 * Specialized rehab centers.
 * At least a 3-month limit to declare permanent dependence.

Links

 * Artificial pulmonary ventilation/SŠ (nurse)