Mechanical Ventilation Support

• Mechanical ventilators support ventilation, augmenting the respiratory process.
• Nurses collaborate with a multidisciplinary team to organize care during initiation, ongoing care, and weaning from ventilator support.
• Knowledge of artificial airways and tracheostomy tubes supports evidence-based care.
• Prior familiarity with pulmonary gas exchange and alterations in pulmonary function is suggested.

Determining the Need for Ventilatory Support

• The invasiveness of artificial airways and associated physiologic changes place patients at risk for complications.
• Weigh the relative benefits and risks before using mechanical ventilation.
• Mechanical ventilation is a supportive intervention to aid oxygenation and ventilation while correcting the underlying problem.
• Initiate ventilator support as a "semi-elective" procedure before hemodynamic instability. Early support may improve outcome.
• Criteria established by pulmonary experts aid the healthcare team in determining ventilatory support needs.
• Criteria are based on ventilation and oxygenation status, not specific medical diagnoses.
• Acute respiratory failure (ARF) labels failure of ventilation, oxygenation, or both.
• Clinically, ARF is defined as Paco2 greater than 50 mm Hg with pH less than 7.30, and/or Pao2 less than 60 mm Hg.
• Patients needing mechanical ventilation typically develop one type of ARF as their primary pulmonary dysfunction.
• ARF is broken into acute ventilatory failure and oxygenation failure to establish criteria for mechanical ventilation.

Acute Ventilatory Failure

• Acute ventilatory failure (AVF) indicates ventilator support.
• AVF indicates the lungs' inability to maintain adequate alveolar ventilation.
• AVF can be diagnosed on the basis of acid-base imbalance, creating acute respiratory acidosis.
• AVF is expressed as Paco2 greater than 50 mm Hg and pH less than 7.30.
• AVF can be caused by brain trauma, apnea neuromuscular dysfunction, pneumonia, sepsis, acute respiratory distress syndrome (ARDS), heart failure, and drug-induced central nervous system (CNS) depression.
• Any problem reducing air movement to and from the alveoli (alveolar hypoventilation) can cause to AVF.
• AVF is a direct indication for rapid intubation and mechanical ventilatory support.
• Consider consciousness level or degree of respiratory acidosis when initiating mechanical support.
• Patients with severe COPD or nonreversible conditions should have informed consent about intubation risks and benefits.
• Advance directives help the team, patient's family, or proxy understand the patient's wishes for intubation and ventilation.
• Conversations and documentation review promote understanding of care goals before a crisis.

Acute Oxygenation Failure

• Hypoxemia indicates mechanical ventilatory support.
• Hypoxemia is frequently quantified as a PaO2 less than 60 mm Hg, indicating oxygenation failure.
• A low ventilation-perfusion (V/Q) ratio is the most common hypoxemia cause.
• Low V/Q indicates excess perfusion relative to ventilation, with the cause often an obstructing mucous plug.
• Conditions associated with low V/Q include asthma, pneumonia, COPD, and atelectasis.
• Low V/Q is associated with shunting, where pulmonary capillary perfusion is normal, but alveolar ventilation lacks.
• Shunting occurs when pulmonary capillary blood circulating gets no oxygen from the affected alveolus.
• Severe shunting is associated with respiratory distress syndromes in infants and adults and with severe pneumonia.

Pulmonary Mechanics

• Pulmonary function testing helps decide if mechanical ventilatory support is needed.
• Testing gives clinicians information about respiratory airflow and muscle strength.
• Pulmonary function tests help identify hypoventilation when evaluating the need for mechanical ventilation.
• Vital capacity, negative inspiratory force, and f are common tests used as criteria.
• Vital capacity (VC) is maximum air expired after maximal inspiration, indicating greatest breathing capacity.
• VC decreases with restrictive pulmonary diseases like pneumonia, atelectasis, and other lung compliance disorders.
• Negative Inspiratory force (NIF) measures negative pressure from inspiratory effort, reflecting respiratory muscle strength.
• Abnormally low NIF levels occur with respiratory muscle fatigue or neuromuscular diseases.
• A sustained respiratory rate over 35 breaths per minute increases work of breathing and leads to respiratory muscle fatigue.
• Pulmonary mechanics play a crucial role in determining readiness for mechanical ventilation removal.

Special Considerations

• Older patients are at risk for respiratory failure due to pulmonary and nonpulmonary reasons.
• Age-related changes in pulmonary physiology place older adults at risk.
• Changes include decreased chest wall compliance increasing work of breathing, decreased oxygenation from structural lung changes, and decreased lung volume/strength.
• Reduced sensitivity to hypoxemia, high CO2, and changes in drug metabolism may increase narcotics' and sedatives' respiratory depressive effects.
• Lung diseases like COPD become more evident with age.
• Age-related changes and comorbid conditions affect respiratory activity.
• Heart conditions cause low ejection fraction with heart failure, leading to pulmonary edema and hypoxemia.
• Renal disease alters buffer and fluid volume, precipitating acid-base imbalances/pulmonary congestion.
• Nutrition and decreased muscle strength are risk factors due to functional deconditioning.

Initial Equipment Necessary for Establishment of a Patent Airway

• Mechanical ventilation requires artificial airways.
• Artificial airways include endotracheal and tracheostomy tubes.
• Endotracheal tubes are semirigid radiopaque tubes.
• The curved shaft eases the tube's passage through the upper airway.
• Adult tubes need a cuff for positive pressure ventilation, a balloon sealing the tube from the trachea.
• Neonatal/small pediatric ET tubes lack cuffs, as a sufficient seal is offered by cricoid cartilage in children under age five.
• ET tubes are available with an evacuation lumen above the cuff to suction subglottic secretions that have accumulated.
• Suctioning decreases the risk of ventilator-associated pneumonia.

Choice of Endotracheal Tube Size and Route

• ET tube size depends on person's age.
• ET tube sizes range from 2 mm to 11 mm to reflect the inside lumen diameter.
• Route of entry impacts determining the size for adult ET tubes
• Smaller tubes are required for nasal insertion because nasal airway passage are significantly smaller than oral passages. Designate qualified staff to intubate
• Use the orotracheal route rather than the nasotracheal route
• Although nasotracheal tube may be more comfortable, it carries greater risk of sinusitis/other infections than orotracheal tubes.
• Other problems with the smaller tube needed to intubate nasally include increased airway resistance, chance of tube kinking, difficulty suctioning.
• Reserve the nasotracheal intubation for situations facial trauma/other considerations make oral intubation impossible.

Intubation Equipment

• Before beginning intubation, the designated staff member credentialed in endotracheal intubation ensures that the the following below are at hand:
• Soft-cuffed ET tubes (in variety of sizes) and Sterilet- to keep the tube stiff while guiding the tube in place (for orotracheal route only)
• Laryngoscope handle with blade attached and functional light source, topical anesthetic to promote comfort and local anesthesia
• Also Magill forceps to assist guiding tube past the pharyngeal section, and suction machine or setup to wall-mounted suction head.
• Always have Suction catheter kit w/sterile gloves, a Yankauer (oral) suction catheter to clear the airway of secretions.
• Syringe for cuff inflation, Water-soluble lubricant to ease insertion into the ET tube.
• Have an Endotracheal tube-holding device like adhesive tape to secure tube after insertion.
• Make sure to have personal protective equipment and Stethoscope to auscultate bilateral lung sounds for insertion
• Sedative medication (licensed pro) and IV access to provide for the patient's comfort/safety and expedite the process .
• CO2 detector device- aids in identifying tube location but emergency tracheostomy might be performed for upper airway obstruction from a neck surgery procedure

Tracheostomy Tubes

• Generally the initial access for mechanical ventilation until a longert time to perform. Patients may receive these in emergency situations from severe edema of the throat when they are unable to wean the patient from the ventilator.
• Hospitals establish guidelines for limiting the length a person can have an ET tube in before receiving a tracheostomy.
• Prolonging the use of the ET or Nasotracheal Tubes may include pressure sores, which some studies note arbitrarty timings dont demonstrate benefits in tracheostomy,
• Benefits of transition to tracheostomy tubes gives potential from less sedation can be placed percutaneous with sedation. Type varies in diameter including size.
• Initial tubes are made of plastic and ET tubes can be placed surgically by making an incision in the OR as needed
• Air inflated assures volume from the ventilator

Securing the Artificial Airway and Tracheostomy Placement

• ET tubes must be fitted securely in a way to stop trauma properly that can be secured with adhesive tape
• Commercial ET stabilizers are preferred and tracheostomy tubes that are secured with twill tape and sutures depending on need
• Different cannulas and placements along with inner materials that consist of Teflon and metal, can be sterile or foam
• Fenestrated tubes that are not used with speaking valves have an opening on the posterior to assist weaning and airflow to facilitate speech that must be cleaned

Supportive Equipment

• Supplies and equipment be readily ready, including 2 oxygen sources, the first being ventilation and the other at 100%.
• If positive end-expiratory pressures are in place, the machine might be used if closed suctioning isnt an option. Suction with a catheter,oral phryngeal airway is prepped

Post Intubation

• Immediately following intubation, measure with with carbon dixoide measure along with equal breath sounds from 2-3cm to ensure everything is properly placed
• Check with the lungs via manual resusitiatation bags, auscutlate is there are any possible infections present for any esophageal tube

1,2,3... Section Two Review, correct answers in order:

• 1. D, 2.A, 3.D, 4 (A,B,C)
• 2 types of classification based on which negative or positive pressure is measured

Negative Pressure

• First type to perform negatively to an airtight unit to reduce pressure. Amount used is base on desierde levels.

Pressure Ventilation : Main Support in Acute Centers

• ET or Trachelstomy with various models of positive and pressure
• Cycling Mechanism to describe bases if expriatory and inspiration phases are
• The mechanism limits inspiration with multiple cycling, healthcare in can use several without switching ventilators
• Presure with constant volume depending in lungs and resistance
• Potentially serious problems if system increases with lungs is stiffen