mechanical ventilation for nurses(1).pptx

Mechanical ventilation is a type of therapy that helps you breathe or breathes for you when you can’t breathe on your own. You might be on a ventilator during surgery or if your lungs aren’t working properly. Mechanical ventilation keeps your airways open, delivers oxygen and removes carbon dioxide.

1. Mechanical ventilator

2. Learning Objectives: Upon completion of this lecture, the student nurse will be able to: Identify the induction of mechanical ventilator. List criteria of for institution of ventilator support. Mention the most commonly types of mechanical ventilation Identify the different weaning methods Recognize complications of MV Identify nursing care of patient on MV

3. Definition : Ventilator is a machine that provides respiratory support to patients who cannot breathe on their own, or who cannot breathe well enough to oxygenate their bodies. The air reaches the lungs via an endotracheal (ET) tube which travels from the mouth or nose into the trachea, the tube in the throat that carries air to the lungs.

4. Goals of Mechanical Ventilation Relieve respiratory distress Decrease work of breathing Improve secretion clearance Reverse bronchospasm Apply PEEP/CPAP Decrease auto-PEEP Appropriate positioning Synchronize machine output to patient demand Improve pulmonary gas exchange Reverse respiratory muscle fatigue Permit lung healing Avoid complications

5.   Indications for MV Mechanical ventilation is indicated when the patient's spontaneous ventilation is inadequate to sustain life. In addition, it is indicated as a measure to control ventilation in critically ill patients and as prophylaxis for impending collapse of other physiologic functions . 1- The main indication for mechanical ventilation is respiratory failure.

6. Causes of Respiratory Failure Inadequate gas exchange Pneumonia, pulmonary oedema, acute respiratory distress syndrome (ARDS) Inadequate breathing Chest wall problems e.g. fractured ribs Pleural wall problems e.g. pneumothorax, haemothorax Respiratory muscle failure e.g. myasthenia gravis, poliomyelitis, tetanus Central nervous system depression e.g. drugs, brain stem compression Obstructed breathing Upper airway obstruction eg epiglottitis, oedema, tumour Lower airway obstruction eg bronchospasm

7. 2- Others Control of intracranial pressure in head injury Airway protection following drug overdose Following cardiac arrest For recovery after prolonged major surgery or trauma (Upper abdominal/thoracic surgery) altered conscious level, inability to protect the airway Cardiac disease: poor left Ventricle function, pulmonary edema

8. Criteria for institution of ventilatory support Criteria value Normal range Critical level 1-Respiratory muscle performance     Vital capacity (VC) 65–75 mL/kg <15 mL/kg Tidal volume (V1) 5–8 mL/kg <5 mL/kg Respiratory frequency (f) 12–20 breaths/min >35 breaths/min 2- Ventilation     pH 7.35–7.45 <7.25 P a CO 2 35–45 mmHg >55 mmHg, and rising P a O 2 80–100 mmHg <60 mmHg P a O 2 /FIO 2 300-400 <200

9. Types of Ventilators There are two general kinds of ventilators: negative pressure and positive pressure. 1-Negative Pressure Examples of these include the iron lung, these ventilators enclosed the body from the outside. The original ventilators used negative pressure to remove and replace gas from the ventilator chamber. As gas was pulled out of the ventilator chamber, the resulting negative pressure caused the chest wall to expand, which pulled gas into the lungs. The cessation of the negative pressure caused the chest wall to fall and exhalation to occur. While it’s an advantage that these ventilators didn’t require insertion of an artificial airway, they were noisy and made nursing care difficult. These ventilators are no longer commonly used in the critical care environment

10. 2-Positive pressure Ventilators that require an artificial airway (endotracheal or tracheostomy tube), and use positive pressure to force oxygen into a patient’s lungs. Inspiration can be triggered either by the patient or the machine. There are four types of positive pressure ventilators: volume cycled, pressure cycled, flow cycled, and time cycled

11. Volume-cycled ventilators are designed to deliver a preset tidal volume of air to be with each inspiration, and then allow passive expiration. This is ideal for patients with bronchospasm since the same tidal volume is delivered regardless of the amount of airway resistance. The most commonly used in critical care environments.        

12. Pressure-cycled ventilators deliver gases at preset pressure, and then allow passive expiration. The benefit of this is a decreased risk of lung damage from high inspiratory pressures. The disadvantage of these ventilators is that the patient may not receive the complete tidal volume if he or she has poor lung compliance and increased airway resistance. This type of ventilation is usually used for short-term therapy (less than 24 hours). Flow-cycled ventilators deliver a breath until a preset flow rate is achieved during inspiration. Time-cycled ventilators terminate or control inspiration after a preset time.

13. Ventilator Modes Mode refers to how the machine will ventilate the patient in relation to the patient’s own respiratory efforts. Control Mandatory Ventilation (CMV) CV delivers the preset volume or pressure regardless of the patient’s own inspiratory efforts. This mode is used for patients who are unable to initiate a breath (apnea). If it is used with spontaneously breathing patients, they must be sedated and/or pharmacologically paralyzed. Inspiration is initiated by timing device. Machine controlled breath

14. Assist-Control Ventilation (A/C) A/C delivers the preset volume or pressure in response to the patient’s own inspiratory effort, but will initiate the breath if the patient does not do so within the set amount of time. This means that any inspiratory attempt by the patient triggers a ventilator breath. The patient may need to be sedated to limit the number of spontaneous breaths since hyperventilation can occur. This mode is used for patients who can inititate a breath (for spontaneously breathing patients) but who have weakened respiratory muscles.

15. Intermittent mandatory ventilation With intermittent mandatory ventilation (IMV), breaths are delivered at a preset interval, and spontaneous breathing is allowed between ventilator-administered breaths. Spontaneous breathing occurs against the resistance of the airway tubing and ventilator valves, which may be formidable. This mode has given way to synchronous intermittent mandatory ventilation (SIMV).

16. Synchronous Intermittent Mandatory Ventilation (SIMV) SIMV was developed as a result of the problem of high respiratory rates associated with A/C. SIMV delivers the preset volume or pressure and rate while allowing the patient to breathe spontaneously in between ventilator breaths. Each ventilator breath is delivered in synchrony with the patient’s breaths, yet the patient is allowed to completely control the spontaneous breaths. SIMV is used as a primary mode of ventilation, as well as a weaning mode. (During weaning, the preset rate is gradually reduced, allowing the patient to slowly regain breathing on his or her own.) The disadvantage of this mode is that it may increase the work of breathing and respiratory muscle fatigue.

17. Pressure Support Ventilation (PSV) PSV is preset pressure that augments the patient’s spontaneous inspiratory effort and decreases the work of breathing. The patient completely controls the respiratory rate and tidal volume. PSV is used for patients with a stable respiratory status and is often used with SIMV to overcome the resistance of breathing through ventilator circuits and tubing. The patient breathes spontaneously with pressure assistance to each spontaneous inspiration. Pressure plateaus at set pressure until inspiration ends

18. Adjuncts to Ventilator Modes Positive End Expiratory Pressure (PEEP) PEEP is positive pressure that is applied by the ventilator at the end of expiration. This mode does not deliver breaths, but is used as an adjunct to CV, A/C, and SIMV to improve oxygenation by opening collapsed alveoli at the end of expiration. Complications from the increased pressure can include decreased cardiac output, pneumothorax, and increased intracranial pressure.

19. Constant Positive Airway Pressure (CPAP) CPAP is similar to PEEP except that it works only for patients who are breathing spontaneously.  CPAP can also be administered using a mask and CPAP machine for patients who do not require mechanical ventilation, but who need respiratory support; for example, patients with sleep apnea.

20. CPAP can also be delivered through either a nasal mask or a full face mask. Full face masks minimize air leaks, and they must be removed for the patient to speak or expectorate secretions. A separate CPAP machine is used to deliver noninvasive CPAP rather than the ICU ventilator. CPAP Maintains constant positive pressure in airways so resistance and the work of breathing are decreased. The patient breathes spontaneously through the ventilator at an elevated baseline pressure throughout the breathing cycle. Increases lung volumes, improves oxygenation

21. Ventilator Settings Ventilator settings are ordered by the physician and are individualized for each patient. Respiratory Rate (RR) The respiratory rate is the number of breaths the ventilator delivers to the patient each minute. The rate chosen depends on the tidal volume, the type of pulmonary pathology, and the patient’s target P a CO 2 . Patients with normal pulmonary mechanics can tolerate a rate of 8-12 breaths/minute.

22. Tidal Volume (VT) The tidal volume is the volume of gas the ventilator delivers to the patient with each breath. The usual setting is 5-15 mL/kg, based on compliance, resistance, and type of pathology. The tidal volume parameters are set above and below the desired number, and the alarm will sound if the patient’s actual tidal volume is outside of the desired range.

23. Fractional Inspired Oxygen (FIO2) The fractional inspired oxygen is the amount of oxygen delivered to the patient. It can range from 21% (room air) to 100%. 100% oxygen should not be used continuously for long periods of time because of the risk of oxygen toxicity. Once the patient is stabilized, the FIO 2 can be weaned down based on pulse oximetry and arterial blood gas values.

24. Inspiratory: Expiratory (I: E) Ratio or Inspiratory time The I:E ratio is usually set at 1:2 or 1:1.5 to approximate the normal physiology of inspiration and expiration Peak Inspiratory Pressure: Reflects airway resistance and lung compliance (work required to move air through the airways and into the alveoli). Elevated with either increased resistance (tracheal tube, ventilator circuitry) or decreased compliance.

25. Pressure Limit The pressure limit regulates the amount of pressure the volume-cycled ventilator can generate to deliver the preset tidal volume. Because high pressures can cause lung injury, it’s recommended that the plateau pressure not exceed 35 cm H2O. If this limit is reached, the ventilator stops delivering the breath and alarms. This may be an indication that the patient’s airway is obstructed with mucus, the high pressure is usually resolved with suctioning. It can also be caused by the patient coughing, biting on the ETT, breathing against the ventilator, or by a kink in the ventilator tubing.

26. Flow Rate The flow rate is the speed with which the tidal volume is delivered. The usual setting is 40-100 liters per minute. Sensitivity/Trigger The sensitivity determines the amount of effort required by the patient to initiate inspiration. It can be set to be triggered by pressure or flow. (-0.5 to -2 cmH2O)

27. Sigh The ventilator can be programmed to deliver an occasional sigh with a larger tidal volume because it was thought that it prevented collapse of the alveoli(atelectasis). However, recently there has been concern that the increased pressure produced in the alveoli may heighten the risk of the alveoli rupturing and causing pneumothorax. The usual volume is 1.5-2 times tidal volume, and usual rate is 4-5 times/ hour.

28. Initial ventilator settings FiO 2 1.0 initially but then reduce PEEP 5 cm H 2 O Tidal volume 7-10 ml/kg Inspiratory pressure 20 cm H 2 O (15cmH2O above Frequency 10 - 15 breaths per minute I:E Ratio 1 : 2 Flow trigger 2 l/min Pressure trigger - 1 to -3 cm H 2 O

29. Ventilator alarms Alarm problem Causes Interventions 1. High pressure “Increase in peak airway pressure” Patient coughing  Secretions or mucus in the airway  Patient biting tube  Airway problems  Reduced lung compliance ( eg. pneumothorax)  Atelectasis or bronchospasm Increased airway resistance  Patient fighting the ventilator  Accumulation of water in the circuit  Tubing kinked Problems with inspiratory or expiratory valves   Suction secretions as needed Ensure water condensation from tubing does not drain into patient’s airway Prevent tube kinking and movement during turning patient Administer bronchodilators as ordered Implement effective communication system Explain why not to bite down on tube ; use tube securing method with bite block if needed Assess for hypoxia or bronchospasm. Check arterial blood gas values. Sedate only if necessary. Manually ventilate patient; notify physician.

30. 2. Low pressure “Decrease in pressure or loss of volume” Patient disconnection  Increase in compliance Leak in ventilator or tubing; cuff on chest tube humidifier not tight   Assess, correct air leaks in endotracheal, tracheostomy cuff, ventilator system Recheck ventilator and make sure that all connections are secured 3. Apnea Alarm occurs if patient has not triggered a breath within the 20-second apnea interval *Patient stopped breathing because of medications depressing central nervous system, clinical condition Check patient, ventilate manually as needed May need to switch to mode that provides more ventilation support Reevaluate need for medications that are depressing ventilation

31. 4.High respiratory rate Patient anxiety Pain Hypoxia Fever Assure the patient and try to relive patient's anxiety. Notify physician and assess the patient 5 Vent inoperative   Ventilator failure due to Hardware failure or critical software error Ventilate manually call respiratory therapy Respiratory therapist must evaluate/retest ventilator for proper function

32. Nursing intervention of the Mechanically Ventilated Patient

33. Weaning from mechanical ventilation

34. During the ventilatory weaning process, the modes of mechanical ventilation are gradually changed to allow the patient to initiate more breaths while the ventilator provides fewer breaths until patient is sufficiently recovered to breathe on his own.

35. Factors that affect weaning process Weaning techniques Weaning criteria or predictors Work of breathing, Muscle weakness and fatigue Nutrition Humidification

36. Methods of Weaning There are three primary methods used to wean patients from the ventilator. These include T-piece/CPAP trials, Synchronized Intermittent Mandatory Ventilation (SIMV), and Pressure Support Ventilation (PSV). PSV is often used with SIMV to decrease the work of breathing. PSV augments the patient’s spontaneous inspiration with a positive pressure” which decreases the resistance created from breathing through ventilator tubing. CPAP maintains constant positive pressure in the airways, which facilitates gas exchange in the alveoli. The weaning method chosen depends on the patient’s respiratory status and the length of time that he or she has been on the ventilator.

37. T-piece Trials: T-piece trials consist of alternating intervals of time on the ventilator with intervals of spontaneous breathing. To facilitate spontaneous breathing, the patient is removed from the ventilator and a T-shaped tube is attached to the endotracheal or tracheostomy tube. One end of this tubing is attached to an oxygen flowmeter and the other end is open; the amount of oxygen used is ordered by the physician. If they tire out or their respiratory status becomes unstable, they should be reconnected to the ventilator. The goal of this method of weaning is to gradually increase the amount of time spent off the ventilator.

38. T-piece

39. Indicators of Weaning Failure Inadequate gas exchange Arterial oxygenation saturation (S a O 2 ) <85% - 90% P a O 2 <50 – 60 mmHg pH < 7.32 Increase in P a CO 2 >10 mmHg Respiratory rate >30 – 35 breaths/minute

40. Hemodynamic instability Heart rate >120 – 140 beats/minute Systolic blood pressure >180 mmHg or diastolic <90 mmHg Change in mental status Coma Agitation Anxiety

41. Signs of increased work of breathing Nasal flaring Use of accessory respiratory muscles Onset of worsening discomfort ± diaphoresis

42. Complications of Mechanical Ventilation Pulmonary System Barotrauma and pneumothorax due to high pressures lead to alveolar rupture ETT displacement or extubation Tracheal damage Oxygen toxicity Acid-Base Disturbances Aspiration Infection Ventilator Dependence

43. Cardiovascular Decreased venous return and cardiac output due to application of positive pressure to lungs Hypotension Fluid retention

44. Neurovascular Increased ICP Decreased cerebral perfusion pressure Renal Decreased urinary output Fluid retention GIT system Stress ulcers and GIT bleeding May develop paralytic ileus Inadequate nutrition common Constipation

45. Sensory Conjunctivitis Impaired communication

46. Nursing Care of the Mechanically Ventilated Patient A- Assessment of the patient B- Assessment of the ventilator: - Ventilator settings - Ventilator alarms - Ventilator connections and tubing - Humidifier

47. A- Assessment of the patient The respiratory status of patients who are mechanically ventilated must be frequently assessed. Breath Sounds: Breath sounds should be assessed at least every four hours.   Spontaneous Respiratory Rate and Tidal Volume If the spontaneous tidal volume is low and the respiratory rate is high, it may indicate that the patient isn’t tolerating the weaning attempts, needs suctioning, or is anxious or trying to communicate. Pulse Oximetry to measure oxygen saturation (SpO 2 ).

48. (Capnography) End Tidal CO 2 measured at the end of exhalation to confirm ETT placement in the lung. Arterial Blood Gases (ABGs) The arterial oxygen tension (P a O 2 ) indicates the degree of oxygenation of the blood, and the arterial carbon dioxide tension (P a CO 2 ) indicates the adequacy of alveolar ventilation. Arterial blood gas studies aid in assessing the ability of the lungs to provide adequate oxygen and remove carbon dioxide and the ability of the kidneys to reabsorb or excrete bicarbonate ions to maintain normal body pH. pH: 7.35 -7.45 P a CO 2 : 35-45 mm Hg HCO3: 22-26 mEq /L P a O 2 : 93-98%

49. Assessment parameters System Artificial airway: • Tube placement • Tube security • Cuff status Airway patency: • Assessment of lung secretions (suctioning) • Adequacy of humidification Breathing: • Respiratory rate, volume and pressure • ABG analysis • Pulse oximetry and capnometry Respiratory

50. • Heart rate and rhythm • Blood pressure • Central venous pressure • Peripheral perfusion • Chest X-ray interpretation • Measurement of cardiac output • Observe for signs of DVT Cardiovascular • Glasgow Coma Score • Ability to communicate • Sedation Neurological

51. • Abdominal discomfort/distension • Presence of bowel sounds • Amount and characteristics of gastric aspirates • Frequency of bowel movement • Physical strength and body weight • Serum phosphate level and liver function tests Gastrointestinal • Temperature and blood glucose level Metabolic • Urine output, serum electrolytes, urea and creatinine Renal • Observe for presence of pressure ulcers Skin integrity

52. B- Assessment of the ventilator -Ventilator settings Modes of ventilation. FiO 2 . Tidal volume VT. Minute ventilation VE. Respiratory rate. PEEP or CPAP. I: E ratio. - Ventilator alarms - Ventilator connections and tubing - Humidifier Humidifier temperature Level of water in the humidifier

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