SUBJECT: Small volume nebulization of medications to patients on mechanical ventilation.

PURPOSE: To define procedure for administration of nebulized medications to patients on mechanical ventilation.

POLICY:

3. Nebulizers are discarded and replaced with new daily and when visibly soiled.

INDICATIONS: Bronchodilator aerosol administration and evaluation of response are indicated whenever bronchoconstriction or increased airways resistance is documented or suspected in patients during mechanical ventilation. Some possible indications are:

1. Known expiratory airflow obstruction.
2. Previous demonstrated response to bronchodilator.
3. Presence of auto-PEEP not eliminated with reduced rate, increased inspiratory flow, or decreased inspiratory to expiratory time ratio.
4. Increased airway resistance as evidenced by increased peak inspiratory pressure and plateau pressure difference, wheezing or decreased breath sounds, intercostal and/or sternal retractions, or patient-ventilator dysynchrony.

CONTRAINDICATIONS:

• Certain medications may be contraindicated in some patients. Consult the package insert for product-specific contraindications.

• Some assessment maneuvers may be contraindicated for patients in extremis (eg, prolonged inspiratory pause for patients with high auto-PEEP).

EQUIPMENT:

• Small volume nebulizer set.

• Large bore tubing and connector at a length to place the nebulizer aproximately 30 cm from patient.

• Oxygen flowmeter.

• Ventilator with capability to measure end-inspiratory and end-expiratory pause, intrinsic PEEP ("auto-PEEP"), pressures, flows, and volumes.

• Pulse oximeter

• Stethoscope

• Cardiac monitor, when available

PROCEDURE:

1. Assess patient.
2. Place medication in dry nebulizer.
3. Place nebulizer securely in ventilator curcuit on inspiratory side aproximately 30 cm back from endotracheal tube. Assure no leaks are present.
4. If heated humidifier is in use place it in pause mode during nebulization. If heat and moisture exchanger (HME) is in use remove it from the circuit during nebulization.
5. Assure that a filter is in place in the expiratory limb between the patient and the ventilator.
6. Optimize ventilator settings as patient tolerates to maximize medication deposition (Consider the following, if not otherwise contraindicated--(1) Use of a tidal volume > 500 mL for adults; (2) addition of an inspiratory pause or lower flows, which may improve pulmonary deposition of aerosol; however clinical judgment and patient evaluation must assure that the patient's inspiratory flow demands are met and risk of baro/volu-trauma is not increased (ie, the inspiratory-to-expiratory-time ratio is subjectively and physiologically appropriate, auto-PEEP is not increased, Pplat does not rise above 35 cmH2O); (3) because spontaneous breaths may improve aerosol delivery, spontaneous breathing should not be suppressed during aerosol therapy unless the patient's ability to trigger the ventilator is affected). Flow from the flowmeter to the nebulizer may affect the delivered tidal volume, the inspired oxygen concentration, and the patient's ability to trigger the ventilator. It may be necessary to decrease the set tidal volume. For a patient triggering the ventilator, the rate may need to be increased to maintain an appropriate minute ventilation
7. Start flow to nebulizer at 6-10 LPM.
8. Assess patient and ventilator. Make necessary modifications to safely optimize medication delivery.
9. When medication has been delivered re-establish origional ventilator circuit configuration and ventilator settings.
10. Assess patient.
11. Perform patient/ventilator system check.

• Document in patient chart:

• Medication type, dose, and time received in patient chart.

• Measured responses such as vital signs, lung function as reflected by changes in peak inspiratory pressure (PIP), plateau pressure (Pplat), auto-PEEP (PEEPi), and bedside observations. (note observations relative to time of administration).

• Other significant observations (general appearance, presence of tremor, use of accessory muscles or patient-ventilator dysynchrony, percussion and auscultation, including presence or absence of wheezing, patient symptoms, improvement in dyspnea, changes in SaO2 or SpO2, changes in ventilator variables, Pinsp-Pplat difference, inspiratory and expiratory resistance, expiratory flow, flow-volume loop, subjective response, changes in sputum clearance, changes in arterial blood gas values, adverse response to drug).

PRECAUTIONS AND/OR POSSIBLE COMPLICATIONS:

• Specific assessment procedures may have inherent hazards or complications: (eg, inspiratory pause, expiratory pause).

• Inappropriate device selection or inappropriate use of device and/or technique variables may result in underdosing.

• Device malfunction may result in reduced drug delivery and may possibly compromise the integrity of the ventilator circuit.

• Complications of specific pharmacologic agents. Higher doses of beta agonists may cause adverse effects secondary to systemic absorption. The potential for hypokalemia and atrial and ventricular dysrhythmias may exist with high doses in critically ill patients.

• Aerosol medication, or cold, dry gas that bypasses the natural upper respiratory tract may cause bronchospasm or irritation of the airway.

• The aerosol device or adapter used and technique of operation may affect ventilator performance characteristics and/or alter the sensitivity of the alarm systems.

• Addition of gas to the ventilator circuit from a nebulizer may increase volumes, flows, and peak airway pressures, thus altering the intended pattern of ventilation. Ventilator setting adjustments made to accommodate the additional gas flow during nebulization must be reset at the end of the treatment.

• Addition of gas from a nebulizer into the ventilator circuit may result in the patient's becoming unable to trigger the ventilator during nebulization, leading to hypoventilation.

• When gas flow driving the nebulizer is from a secondary gas source (other than the ventilator), the volumes, flows, and pressures delivered by the ventilator to the patient are altered.

• Nebulizers in line with the ventilator circuit tend to collect condensate when not in use and should be removed from ventilator circuit and allowed to dry between treatments.

• Nebulizers are vulnerable to contamination, posing consequent increased risk for nosocomial infection.

• Nebulizers should be changed at 24-hour intervals and whenever visibly soiled. Nebulizers should not rinsed with tap water between treatments.

• Medications should be handled aseptically.

• Medications from multidose sources must be handled aseptically and discarded after 24 hours or as recommended by manufacturer.

AARC Clinical Practice Guideline - Selection of Device, Administration of Bronchodilator, and Evaluation of Response to Therapy in Mechanically Ventilated Patients. Respir Care 1999;44(1):105-113