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INITIAL VENTILATOR SETTINGS 4 nurses
This document provides guidance on initial ventilator settings for mechanically ventilated patients. The goals of mechanical ventilation are to improve gas exchange, relieve respiratory distress, improve pulmonary mechanics, and permit lung healing while avoiding complications. Initial settings include ventilator mode (full or partial support), frequency (10-12 breaths per minute), tidal volume (6-8 ml/kg ideal body weight), fraction of inspired oxygen (100% for severe cases then titrated), positive end-expiratory pressure (5 cm H2O initially), pressure support for weaning, and inspiratory to expiratory ratio (1:2 to 1:4 typically). Settings may require adjustment based on blood gas results and patient tolerance.
INITIAL VENTILATOR SETTINGS 4 nurses
- 1. INITIAL VENTILATOR SETTINGS MANISH MASIH CRITICALCARE THERAPIST(B.SC) DUNCAN HOSPITAL, RAXAUL
- 2. GOALS OF MECHANICALVENTILATION Mechanical ventilation alone does not treat or reverse the underlying pathology leading to the need for ventilator support. Rather, it is applied as one of the support systems until the reversal of the pathological condition, so that the patient may then become weaned from mechanical ventilation.
- 3. GOAL Improve gas exchange Reliverespiratory distress Improve pulmonary mechanics Permit lung and airway healing Avoid complication TARGET Reverse hypoxemia/Relieve acute respiratory acidosis Reverse respiratory muscle fatigue Prevent and reverse atelectasis Improve lung compliance/Maintain lung and airway function Prevent disuse respiratory muscle dystrophy
- 4. INITIAL VENTILATOR SETTINGS Mode Frequency, Tidalvolume, FIO2, inspiratory: expiratory ratio, inspiratory flow pattern, and Various alarm limits.
- 5. Mode full ventilatory support(FVS) or partial ventilatory support (PVS). synchronized intermittent mandatory ventilation - provides full ventilatory support if the patient is not breathing spontaneously between mechanical breaths, and the mandatory frequency is set at 12/min or higher.
- 6. Frequency intended to provideeucapneic ventilation (PaCO2 at patient’s normal). usually set between 10 and 12/min Frequencies of 20/min or higher are associated with auto-PEEP and should be avoided ˄ frequency if the PaCO2is too high; ˅ frequency if thePaCO2 is too low. Minute ventilation
- 7. Tidal Volume Initial 6to 8 ml/kg IBW IBW = (Ht – 152.4) * 0.91 + 45 for female / + 50 for male Tidal volumes as low as 6 mL per kg of predicted body weight have been recommended for ARDS patients The primary reason for using lower tidal volumes (i.e., permissive hypercapnia) is to minimize the airway pressures and the risk of barotrauma
- 8. Conditions That MayRequire Lower Tidal Volumes CONDITION Increase of airway pressure requirement Increase of lung compliance Decrease of lung volumes EXAMPLES ARDS / Pulmonary edema Emphysema Pneumonectomy
- 9. Pressure Support used toaugment a patient’s breathing effort by reducing the airflow resistance during spontaneous breathing available in modes of ventilation that allows spontaneous breathing (e.g., SIMV). For weaning A PSV of greater than 30 cm H2O is rarely needed since these patients are typically not ready for weaning the PS level is reduced by 2 to 4 cm H2O increments as tolerated. Extubation can be considered when the PS level reaches 5 to 8 cm H2O for 2 hours with no signs of respiratory distress.
- 10. FIO2 For patients withsevere hypoxemia or abnormal cardiopulmonary functions (e.g., post- resuscitation, smoke inhalation, ARDS), the initial FIO2 may be set at 100%. evaluated by means of arterial blood gas analyses adjusted accordingly to maintain a PaO2 between 80 and 100 mm Hg (lower for patients with chronic CO2 retention).
- 11. PEEP Positive end-expiratory pressure(PEEP) increases the functional residual capacity and is useful to treat refractory hypoxemia (low PaO2 not responding to high FIO2) initial PEEP level may be set at 5 cm H2O. PEEP should be based on the patient’s blood gas results, FIO2 requirement, tolerance of PEEP, and cardiovascular responses.
- 12.
- 13. I:E Ratio I:E ratiois the ratio of inspiratory time to expiratory time Kept in the range between 1:2 and 1:4 A larger I:E ratio (longer E ratio) may be used on patients needing additional time for exhalation Inverse I:E ratios have been used to correct refractory hypoxemia in ARDS patients with very low compliance. Inverse I:E ratio should be tried only after traditional strategies have failed to improve a patient’s ventilation and oxygenation status. Note that the I time and I:E ratio are inversely related. A longer I time leads to a lower I:E ratio
- 14. Reference Clinical application ofMechanical Ventilation, David. W .Chang
Editor's Notes
- #8 COPD patients may also benefit from a reduced tidal volume setting. These patients have reduced expiratory flow rates due to decreased alveolar elastic recoil longer expiratory time is needed for complete exhalation For patients with a reduction of lung volumes due to lung resection, lower tidal volumes may also become necessary
- #10 The contributing factors of airflow resistance during mechanical ventilation may include the artificial airway, ventilator circuit, and secretions.
- #14 because of the possibility of air trapping and auto-PEEP. Presence of air trapping during mechanical ventilation may be checked by occluding the expiratory port of the ventilator circuit at the end of exhalation. Depending on the features available on the ventilator, the I:E ratio may be altered by manipulating any one or a combination of the following controls: (1) flow rate, (2) inspiratory time, (3) inspiratory time %, (4) frequency, and (5) minute volume (tidal volume and frequency).