Definition
Mechanical ventilation can be defined as the technique through which gas is moved toward and from the lungs through an external device connected directly to the patient.
Indications for Mechanical Ventilation
- Progressive hypoxia despite oxygen therapy measured by oxygen saturations or blood gas analysis (high PaCO2 and low pH).
- Excessive WOB manifested by retractions, tachypnea, decreasing O, saturation, and abnormal respiratory patterns.
- Inadequate respiratory effort.
- Hyperventilation for treatment of increased.
- intracranial pressure.
- Need for mechanical ventilation for any reason.
- The conditions that cause inadequate ventilation are:
- Apnea.
- Central nervous system injury or infection.
- Alveolar hypoventilation.
- Respiratory muscle weakness.
- Medication toxicity.
- Infectious pathologic condition.
- Foreign body obstruction.
- Pulmonary lavage.
- Instillation of medication.
- Need for short-term ventilation:
- During surgery.
- Acute lung injury.
- Acute respiratory acidosis.
- CCF.
Contraindication
- Unilateral lung disease.
- Obstructive lung disease.
- Pneumothorax.
- Bronchopleural fistula.
- Intracardiac shunt.
- Increased intracranial pressure.
Classifications
Types of Ventilators
- Pressure-cycled ventilator: Terminates the respiratory cycle where a preset inspiratory pressure is reached. Volume differs greatly, depending on the flow rate of the delivery of gas. The lung’s compliance affects the tidal volume (VT) even though the pressure remains constant.
- Volume-cycled ventilator: Terminates respiration when a preset volume (VT) is delivered. The lung’s compliance and resistance change the pressure needed to deliver the preset volume.
- Time-cycled ventilator: Terminates inspiration when a pressure time is reached.
- VT is greatly affected by compliance of the ventilator tubing, lung’s compliance, and resistance and flow rate of the delivered gas. The duration of the inspiratory pressure is affected by the preset inspiratory time and the flow rate of the delivered gas.
- Combined ventilator: It can be used as either volume- or time-cycled, pressure-limited ventilation.
Some Commonly Used Mechanical Ventilator
- Sechrist (pressure type): Pressure control/intermittent mandatory ventilation (IMV)/continuous positive airway pressure (CPAP).
- Sechrist (volume and pressure type): PC/VC/Synchronized IMV (SIMV)/SIMV with PS.
- Servo 300: Numerous.
- VIP Bird: Volume and pressure numerous.
- Drager Babylog: Pressure-numerous.
- Infant star: Pressure-SIMV and A/C.
- LP-10: V&P-SIMV and A/C.
Modes of Mechanical Ventilation
1) Control Mechanical Ventilation
Patient receives a preset number of breaths/min, of a preset VT, patient effort, when not trigger a mechanical breath. The ventilator performs all the WOB.
Indications
- Patient with minimal or no respiratory effort, for example, spinal cord lesion.
- When negative inspiratory effort is contra-indicated, for example, flail chest.
- As a backup to assisted ventilation.
Disadvantages
- Patient-ventilator asynchrony.
- Prolonged use may result in respiratory muscle weakness and atrophy.
2) Assist-control Ventilation
Ventilator delivers a preset number of breaths of a preset VT. Between this machines initiated breath, patient may trigger spontaneous breaths. Patient performs negative inspiratory effort.
Indications
- Normal respiratory drive but respiratory muscles are too weak to perform WOB.
Advantage
- Allows the patient to control the rate of breathing and still it guarantees the delivery of a minimal preset rate and volume.
Disadvantages
- The patient’s tendency to hyperventilate because of anxiety, pain, etc. leads to respiratory alkalosis.
- Variation in patient’s hemodynamic status.
3) Synchronized Intermittent Mandatory Ventilation
It is the same as A/C mode. The main difference between the IMV and A/C mode is the volume of the patient-initiated breaths. In A/C, the VT is guaranteed, whereas in IMV it is variable.
Mandatory breaths may be synchronized with a patient’s spontaneous effort (SIMV) to avoid mandatory breaths occurring during a spontaneous breath. This effort known as “stacking” may lead to excessive VTs, high airway pressure, incomplete exhalation, and air trapping.
Indications
- Normal respiratory drive but respiratory muscles unable to perform all WOB.
- Need to wean the patient from mechanical ventilation.
Advantages
- Decreased rate of hyperventilation.
- Less respiratory muscle atrophy.
- Less hemodynamic efforts of positive-pressure ventilation.
- Improves patient’s comfort and reduces competition between ventilator and patient.
Disadvantages
- Fatigue.
- Atelectasis.
- Reduction in compliance leads to increased WOB and greater need for ventilator support.
4) Time-cycled, Pressure-limited Ventilation
The rate and inspiratory time (I:E) are preset. A preset PIP is determined.
Indication
- Neonates and infants where VT is small.
Advantages
- Precise control of inspiratory time and a rapid respiratory rate.
- Less chance for barotrauma.
Disadvantage
- Inability to detect airway obstruction or kinking due to preset limited PIP (high pressure alarm may go off).
5) Pressure-controlled, Inverse Ratio Ventilation (PCIRV)
PCIRV is a new and potentially promising method of ventilation in which the pressure ventilation with an inspiratory/expiratory (I:E) ratio greater than 1:1 is used. This helps to maintain a high mean airway pressure and hold peak alveolar pressure within a safe range. All breaths are pressure limited and time cycled and the inspiration is longer than expiration.
Indication
- Child with specific noncompliant lung conditions.
Advantages
- Decrease in both PIP and positive-end Advantages expiratory pressure (PEEP) levels.
- Stabilizes the alveoli equilibration of volume.
Disadvantages
- PCIRV can cause hemodynamic instability Disadvantages due to increase intrinsic PEEP and mean airway pressure.
- It can lead to stacking of breaths.
- Can cause ventilator induced lung injuries.
- Can result in significant decrease in cardiac output.
6) Pressure Support Ventilation
Patient’s spontaneous respiratory activity is augmented by the delivery of a preset amount of inspiratory positive pressure and the VT is variable based on patient’s effort.
Indications
- During weaning from mechanical ventilation.
- Long-term mechanical ventilation.
Disadvantage
- Tidal volume would decrease if compliance decreased or resistance increases (bronchospasm or significant secretions).
7) Positive-end Expiratory Pressure
Positive-end expiratory pressure is the application of a constant, positive pressure in the airways so that at end expiration the pressure is never allowed to return to the atmospheric pressure.
Positive-end expiratory pressure, measured in centimeter of water, ranges from 5 to 20 cm of H₂O.
Advantages
- Recruits alveoli, counteracts alveoli and small airway closure during expiration.
- Redistributes lung water so it decreases shunting.
- Increases functional residual capacity.
- Improves compliance and oxygenation.
- It can be added to every type of mechanical ventilation, including spontaneous respiration, where it is known as CPAP.
Mechanical Ventilation Methods
Artificial ventilation methods are mainly divided into positive-pressure and negative-pressure ventilations. Based on the devices used, further it has been classified as given in.
| Method | Description | Remarks |
| Anesthesia bag or flow ventilation systems. | A small collapsible bag that consist of a reservoir bag, an overflow port, and a fresh gas inflow port. | Adjustment of the O2 flow and outlet control valve is necessary. Useful in providing PEEP or CPAP. Adequate training and skill are needed to operate. Hypercapnia and barotrauma may result with improper use. Used more commonly in recovery rooms and NICU. |
| Bag valve mask device or manual resuscitator. | A self-inflating O2 delivery bag that does not require anO2 source for resuscitation and ventilation. The bag can be connected to O2 to provide higher O2 levels than room air. When the child exhales, nonbreathing valve closes allowing exhaled deoxygenated air to escape. | Effective in providing O2 to a child who is in severe respiratory distress or who has suffered a respiratory arrest.A more efficient method of respiratory resuscitation than a mouth-to-mouth resuscitation.Decreases rescuer exposure to communicable diseases.Possible fatigue for rescuer. |
| Laryngeal mask airway. | An inflatable silicone mask and rubber connecting tube that is inserted blindly into the airway forming seal. | The airway is introduced into the pharynx and advanced until it meets resistance. Ballon cuff is then inflated. Easier insertion than a trachea tube. Used in unconscious child. Patient comfort. |
| Tracheal intubation | A plastic tube is inserted in the trachea to establish and maintain an airway when the airway cannot be maintained effectively using other measures. For example, nasal trumpet or bag valve mask ventilation | Skilled medical professional (physician, nurse practitioner, respiratory specialist) necessary for insertion. The nurse act as a valuable assistant during the intubation procedure. |
(CPAP: continuous positive airway pressure; PEEP: positive-end expiratory pressure).
Formula for calculating appropriate size of ET tube:
Size of ET tube = Age in years + 16÷4.
Equipment for ET Tube Insertion
An emergency trolley containing:
- Laryngoscope blades:
- Straight blades (Miller)- for infants and young children.
- Curved blades (Macintosh) -for older children.
- ET tubes (three sizes).
- Oxygen source, bag valve mask.
- Suction apparatus, appropriate-size suction catheters.
- Pulse oximeter, cardiac monitor.
- Gloves, gown, and mask.
- Adhesive tapes.
- Gauze pads.
Types of ET Intubation
1. Orotracheal.
2. Nasotracheal (most beneficial).
3. Tracheostomy (for prolonged ventilation).
Procedure (Assisting with Ventilation)
- Prepare equipment and supplies.
- Draw up medications.
- Turn up the volume on the cardiac monitor so that members of the team can easily hear the audible QRS indication of the child’s heart rate and note any bradycardia with the procedure.
- Turn on the suction. Make sure that suction is working by placing your hand over the tubing before you attach the suction catheter.
- Continue to ventilate the child with 100% oxygen.
- When there is no suspected cervical spine injury in the child over age 2 years, place a small pillow under the child’s head to facilitate opening of the airway.
- When assisting with the intubation, stand before the patient’s head and prepare to assist with suction of oral secretions, applying cricoid pressure during the insertion of tube providing BVM as needed and assisting with suctioning the tube.
- Before the initial intubation attempt and after each subsequent attempt to intubate, provide several inhalations of 100% 02.
- Administer premedications and medications for sedation.
- Observe whether the healthcare provider who is intubating the child follows the recommended procedure.
Nurse’s Responsibility
Ensuring and Maintaining Correct Tube Placement.
- Observe for symmetrical chest raise and auscultate over the lung fields for equal breath sounds.
- Inspect the tracheal tube for the presence of water vapor on the inside wall, indicating that the tube is in the trachea.
- To rule out accidental esophageal intubation, auscultate over the abdomen (absence of breath sounds).
- Once the tracheal placement is verified, mark the tube with an indelible pen at the level of child’s lip and secure it with tape.
- Document the number on the tracheal tube at the level of child’s mouth.
- Anticipate a chest X-ray to confirm correct placement of the tracheal tube.
- After placement is confirmed, the tracheal tube is connected to the ventilator by respiratory personnel for continuous artificial ventilation.
- To avoid expelling of tube:
- Use soft restraints if necessary to prevent the child from removing the tracheal tube.
- Provide sedative/paralyzing medication.
- Use caution when moving the child for X-rays, changing linens, and performing other procedures.
Monitoring the Intubated Child
- Determine adequacy of O2.
- Auscultate the lungs for equal air entry, determine the HR.
- Perform quick survey of the equipment and look for any disconnected tubes or kinks in the tubing.
- Use the PALS mnemonic “DOPE” for troubleshooting when the status of the child deteriorates.
- D-displacement.
- O-obstruction.
- P-pneumothorax (decrease breath sounds, decreased chest expansion).
- E-equipment failure
- Make sure that all equipment are appropriately connected and functioning.
- Suctioning should be done when necessary
- If displaced, remove the tube from child mouth and begin BVM ventilation.
- Pneumothorax: Prepare to assist with needle thoracotomy.
- Assess nutritional status, intake and output (urine output should be at least 2 mL/kg/h for the infant and younger child and 1 mL/kg/h for the older child), and skin integrity especially around the face and lips for the child with ET tube.
- In some cases, there is increase in the amount of oral or nasal secretions, which requires appropriate perioral skin care.
- The child’s lips and the mouth may be dry and uncomfortable; therefore provision of oral care and moisture is important.
Weaning and Extubation
- Weaning the patient from a ventilator involves gradual physical and psychological withdrawal from dependence on the mechanical device.
- Criteria for weaning may vary with primary disease.
- If the intubated child is receiving nasogastric feedings and is at risk for aspiration, feedings are usually stopped a few hours before extubation.
- Steroids may be administered before extubation to control laryngeal edema.
- The child should remain on cardio-respiratory monitor.
- Resuscitation and reintubation equipment must be available at bedside.
- Perform chest physiotherapy and suctioning just before removal.
- Administer cool mist or oxygen by nasal cannula or mask after extubation.
- Monitor the child for respiratory distress.
- Observe adequacy of oxygen through ABG measurements or pulse oximeter.
Other care includes:
- Monitoring vital parameters
- Monitoring and care of invasive lines
- Maintenance of fluid and electrolyte balance
- Administration of drugs as follows:
| Name | Dose (mg/kg) | IV infusion |
| Sedatives | ||
| Midazolam | 0.05-0.1 | Loading: 0.05 mg/kg/IV Maintenance: 0.025 mg/kg. |
| Fentanyl | 2-10 | Loading:2-10 mg/kg/IV Maintenance: 1-5 mg/kg/h. |
| Morphine | 0.1 | Loading:0.05 mg/kg/IV Maintenance:0.02mg/kg/h. |
| Lorazepam | 0.05-0.1 | |
| Diazepam | 0.1-0.2 | Loading:0.1 mg/kg/h Maintenance:0.3-0.6 mg/kg/h. |
| Muscle relaxants | ||
| Pancuronium Vecuronium Atracurium succinylcholine | 0.1 0.1 0.5 1-2 | |
Complications
Related to immediate intubation:
- Hypoxia.
- Bradycardia.
- Sore throat.
- Traumatic laryngitis.
- Infection.
- Glottic edema.
- Mucosal lesions of larynx due to ET tube pressure.
- Subglottic stenosis secondary to fibrosis (severe complication).
After extubation:
- Airway edema and pain.
- Fatigue.
- Atelectasis.
- Stridor.
REFERENCES
- Annamma Jacob, Rekha, Jhadav Sonali Tarachand: Clinical Nursing Procedures: The Art of Nursing Practice, 5th Edition, March 2023, Jaypee Publishers, ISBN-13: 978-9356961845 ISBN-10: 9356961840
- Omayalachi CON, Manual of Nursing Procedures and Practice, Vol 1, 3 Edition 2023, Published by Wolters Kluwer’s, ISBN: 978-9393553294
- Sandra Nettina, Lippincott Manual of Nursing Practice, 11th Edition, January 2019, Published by Wolters Kluwer’s, ISBN-13:978-9388313285
- Marcia London, Ruth Bindler, Principles of Paediatric Nursing: Caring for Children, 8th Edition, 2023, Pearson Publications, ISBN-13: 9780136859840
- Naveen Bajaj, Rajesh Kumar, Manual of Newborn Nursing, 2nd Edition, 2023, Jaypee Publishers, ISBN:978-9354659294
- Ernstmeyer K, Christman E, editors. Nursing Fundamentals [Internet]. 2nd edition. Eau Claire (WI): Chippewa Valley Technical College; 2024. PART IV, NURSING PROCESS. Available from: https://www.ncbi.nlm.nih.gov/books/NBK610818/
Stories are the threads that bind us; through them, we understand each other, grow, and heal.
JOHN NOORD
Connect with “Nurses Lab Editorial Team”
I hope you found this information helpful. Do you have any questions or comments? Kindly write in comments section. Subscribe the Blog with your email so you can stay updated on upcoming events and the latest articles.