Silverstein and Hopper Chapter 37: Nursing Care of the Ventilator Patient

How can nursing care affect complications in long term ventilation?

• Suggested that humans requiring short-term ventilation have better outcomes than patients requiring long-term ventilation

  • Multiple complications have been associated with long-term ventilation, many of which pertain to nursing care such as oral and corneal ulceration, tracheal tube occlusion or dislodgement, and gastric distension requiring decompression

  • In human medicine, the risk of late-onset, but not early-onset ventilator-associated pneumonia (VAP) is affected by a lower nurse staffing level

General Monitoring for the Ventilator Patient

• Ideal monitoring includes continuous electrocardiography, placement of a rectal thermistor for continuous temperature assessment, pulse oximetry, capnography, and serial blood pressure measurements

• Auscultation of the chest and a cardiovascular physical examination should be performed at least every 4 hours to detect abnormalities as early as possible

• Placement of an arterial catheter allows continuous blood pressure monitoring and arterial blood gas analysis, which should be performed every 4-8 hours or more frequently if indicated

• Patient that develop asynchrony with the ventilator are prone to having elevations in body temperature because of increased heat production from muscular effort

  • May be treated by improving ventilator-patient synchrony, using surface cooling methods (e.g. placement of a fan or use of a cold-water spray bottle), or turning off or removing the humidification system

• Removal of airway humidification should only be performed for short periods because humidification is key to airway management

• Hypothermia may occur as a side effect of anesthetic agents and should be treated with circulating warm-water blankets and forced-air warming devices or by covering the patient with a blanket to reduce heat loss

Hand Hygiene for Artificial Airways

• Whenever a patient with an artificial airway is being handled, hand hygiene should be performed first and examination gloves used to reduce risk of nosocomial infection

• The intubation process should be performed with sterile gloves, ideally with a sterile ET tube

What endotracheal cuffs and pressure are recommended for mechanically ventilated patients?

• Endotracheal tube cuffs can be either high or low volume and high or low pressure, but in veterinary medicine, size will likely restrict these options to low-volume, high-pressure or high-volume, low-pressure cuffs

  • The use of low-pressure cuffs is recommended because cuff pressure greater than 25 cm H2O has been shown to reduce tracheal blood flow which can lead to necrosis and cuff pressures greater than 30 cm H2O should be avoided

Recommendations to Prevent Tracheal Injury in Ventilated Patients

• Use of a cuff pressure monitoring device is recommended to help prevent tracheal damage

• As a precautionary measure to reduce the risk of tracheal injury, it has been suggested to deflate the cuff and reposition it every 4 hours in veterinary medicine

What should endotracheal tube cuff pressure be maintained at to help prevent VAP according to the American Thoracic Society?

At more than 20 cm H2O

ET Cuff Recommendations to Weight the Risk of Tracheal Necrosis vs VAP in Ventilated Patients

• Authors recommend: If a high-volume low-pressure ET tube is used and the cuff pressure can be monitored, the cuff should not be deflated and repositioned, but cuff pressure should be checked every 4 hours. If a low-volume high-pressure ET tube is used or if cuff pressure cannot be monitored, then the cuff should be deflated and repositioned every 4 hours

  • Before deflation and repositioning, oral care and suctioning should be performed to reduce the risk of aspiration

Maintenance of ET Tube Ties in Ventilated Patients

• Secure the ET tube with nonporous material such as plastic IV tubing

• The tie used to secure the ET tube should be retied every 4 hours to prevent damage to the lips and should be replaced every 24 hours to prevent biofilm accumulation

Recommendations for ET Tube Changes in Ventilated Patients

• Reintubation has been shown to increase the risk of VAP in humans

• ET tube occlusion has been reported to occur in up to 14% of animals

  • Patients with exudative pulmonary secretions and smaller diameter ET tubes put them at risk for occlusion and may benefit from an ET tube change every 24-48 hours

  • Patients being ventilated without significant pulmonary secretions or with relatively large diameter ET tubes may only need ET tube changes on an as needed basis

What can lack of humidification of the airways lead to?

Increased mucus viscosity and inspissation, which can cause ET tube occlusion, tracheal inflammation, and depressed ciliary function

What are the two major methods of humidification of the airways?

Heat and moisture exchangers (HMEs)

Heated water humidifiers

Heat and Moisture Exchangers (HMEs)

• Passive HMEs act as an artificial nose by trapping the heat and moisture of exhaled air in the device and then returning them on the following inspiration

• HMEs increase dead space and resistance to airflow

• Have the potential to become obstructed by airway secretions and are often avoided in patients that have copious or tenacious pulmonary secretions

• Should not be changed more frequently than every 48 hours unless they become soiled, obstructed, or mechanically fail

• Ventilator waveforms can be evaluated for increased resistance, indicating a partially occluded HME

Heated Water Humidifiers

• Traditionally considered the gold standard

• Placed in the inspiratory limb of the breathing circuit and allow air to be humidified by passing a heated water reservoir

• Potential complications include overheating and condensation of water in the inspiratory limb, which contributes to bacterial colonization of the breathing circuit

• Condensation in the circuit can be largely prevented by the use of heated wire circuits

What factors contribute to deciding which humidifier to use?

• Decision on which type of humidifier to use should be made based on availability, expected level of secretions, and concerns of increased dead space and resistance to breathing circuit

What are characteristics of the ideal catheter for suctioning the airway?

• Ideal catheter should be soft and flexible, have more than one distal opening, be sterile, and occlude no more than 50% of the internal diameter of the ET tube

What should occur prior to airway suctioning?

The patient should be preoxygenated with 100% oxygen for at least 5 minutes to help prevent hypoxemia during the process

How to Perform Open Suctioning

• With open suctioning, sterile gloves should always be worn by the person manipulating the suction catheter

  • A second person wearing nonsterile gloves should disconnect the breathing circuit from the ET tube to facilitate sterile insertion of the catheter, which should be inserted to the distal end of the ET tube

    • Insertion of the catheter farther than the distal opening of the ET tube risks tracheal inflammation, induction of coughing, or vagal-mediated bradycardia

  • Process should be quick, with the catheter partially occluding the lumen of the ET tube for no more than 10-15 seconds per suction pass

  • Repeat multiple times until secretions are no longer aspirated, with the patient being reconnected to the ventilator in between each suction pass

  • The suction catheter should be cleansed with sterile saline in between suction passes, using a new cup of sterile saline each time to prevent bacterial contamination of the saline container

Closed System Suction Catheters

• Closed system suction catheters are kept in place between the breathing circuit and the patient when not in active use

  • Advantage that the circuit doesn't have to be opened for suctioning, reducing the risk of contamination

  • Do increase dead space of the circuit

How often should the suction cannister and tubing be replaced?

Every 24 hours to minimize the change of bacterial colonization

Addition of Sterile Saline to the Airway to Facilitate Mucus Recovery During Suctioning

• Addition of sterile saline to the airway to facilitate mucus recovery during suctioning is controversial

  • Before suctioning, instillation of 0.1-0.2 mL of 0.9% NaCl into the airway can be considered to help mobilize dry secretions

  • Concerns of saline instillation center around dislodging bacteria from the ET tube and promoting VAP as well as inducing hypoxemia\

  • Benefit may be more effective removal of secretions, which may reduce the likelihood of VAP

Risks of Suctioning an ET tube or Tracheostomy Tube

• Iatrogenic hypoxemia

• Collapse of alveoli as a result of temporary lack of positive end-expiratory pressure

• Tracheal irritation

• Bradycardia

• Hypotension

Complications of Mechanical Ventilation Involving the Oral Cavity

Oral ulceration

Ranula formation

Reflux of gastric contents into the oral cavity

Moistening the Tongue During Mechanical Ventilation

• Tongue is usually moistened with an alternating dilute glycerin-soaked or saline-soaked gauze

  • Avoid wrapping the tongue circumferentially with gauze because this can lead to ranula formation

Oral Care for Mechanically Ventilated Patients

• Lack of swallowing allows for bacteria to proliferate and pool in secretions around the endotracheal tube, increasing the risk for VAP

  • Subglottic suctioning and selective oral decontamination has been shown to decrease the incidence of VAP and oral lesions

• Oral care should be performed every 4 hours

  • The tongue should be inspected for development of a ranula

    • If a ranula is forming, elevating the ET tube to avoid causing pressure on the base of the tongue may be helpful

  • Avoiding placement of the tongue over the teeth as well as the use of a mouth gag may help prevent ulceration

  • Inspect the mouth for mucosal ulcerations and record the depth and size of any identified

• Remove the pulse oximeter probe and any mouth gag and clean them with a dilute 0.12-2% chlorhexidine solution

• Cleanse the entire oral cavity with a specifically formulated 0.12-2% chlorhexidine solution

• Suction the oral cavity and caudal oropharynx to remove remaining chlorhexidine and oral secretions

• Brushing of the teeth twice daily can reduce bacterial oral load and may be considered

• Replace the mouth gag and pulse oximeter in a different position to help prevent ulceration

What eye pathology are ventilator patients at risk for?

• Ventilator patients are at increased risk of exposure keratopathy and microbial keratitis

  • They don't blink so the tear film can't be spread over the eye

• Many patients have lagophthalmos, predisposing them to exposure keratopathy

• Despite eye care, up to 25% of children and 37.5% of adults on mechanical ventilation may develop ocular surface disorders

When does the majority of corneal ulceration develop in ventilated patients?

• The majority of ulceration develops within the first week, however a significant proportion can develop within 48 hours of initiation of mechanical ventilation

What are the two major methods of providing lubrication to the eye in ventilated patients?

Lubricating ointments

Moisture chambers

Lubricating Ointments for Eye Lubrication in Ventilated Patients

• Involves regular cleaning of the eye with sterile saline and replacement with a hyaluronic acid-containing, petroleum-based lubricating ointment

• Considered the standard of care due to the difficulty in obtaining a good seal from a moisture chamber with the various skull structures of dogs and cats

Moisture Chambers for Eye Lubrication in Ventilated Patients

• Doggles or swimmer's goggles to completely seal off the eye from the environment

• Advantage - the cornea is protected even if the eye is open

Eye Care in Ventilated Patients

• Eye care should be performed every 2 hours

  • Lavage the eye and inspect for chemosis, corneal disease, and conjunctivitis

  • If no ulceration is present, a petroleum-based lubricant should be reinstilled

  • If ulceration is present, a broad-spectrum antibiotic ointment should be used every 4 hours

• Fluorescein staining should be performed every 24 hours to evaluate for ulcer formation

• If lagophthalmos or exophthalmos a temporary tarsorrhaphy may be needed

Urinary Care for the Ventilated Patient

• Bladder should be palpated every 4-6 hours and expressed as needed

• If long term ventilation is indicated, the patient may benefit from a urinary catheter

  • Avoids the repeated pressure and trauma of expressing the bladder and allow for more accurate documentation of urine volume

• Urinary catheter care should be performed every 8 hours as long as an indwelling urinary catheter is in place

Risks of Urinary Catheterization

• Development of bacteriuria from true urinary tract infection or colonization of the catheter

• In dogs, the incidence of urinary tract infections associated with indwelling catheterization in nonmyelopathic conditions ranges from 10-20%, with length of catheterization being a risk factor

GI Complications of Mechanical Ventilation

• Esophagitis

• Gastrointestinal bleeding

• Diarrhea

• Ileus

• Constipation

• Gastric distension

• Regurgitation

• Splanchnic hypoperfusion plays an important role in development of many of these complications because of diminished venous return from high levels of positive end-expiratory pressure and increased levels of circulating catecholamines or proinflammatory cytokines

• The incidence of gastrointestinal bleeding in human patients can be as high as 47% with clinically significant bleeding in 3.3% of patients ventilated for more than 24 hours

  • This is less likely in dogs and cats as they are less likely to have stress induced gastric ulceration

What is a modifiable risk factor for GI bleeding in ventilated patients?

Peak inspiratory pressure 30 cmH2O or greater

Benefits of Enteric Nutrition

• Shown to decrease the incidence of GI bleeding and prevent villous atrophy of the intestinal mucosa, potentially reducing the risk of bacterial translocation

Risks of Enteric Nutrition

• May increase the incidence of gastroesophageal reflux and aspiration pneumonia if ileus is present

How can enteral feeding be delivered to ventilated patients?

• Enteral feeding may be delivered via nasogastric, gastrotomy, or jejunostomy tube

  • Esophagostomy tube is not recommended for patients on mechanical ventilation as postesophageal feeding may be associated with a decreased risk of aspiration pneumonia

How should ventilated patients be evaluated for constipation?

The colon should be palpated daily

• If constipation is noted, enemas may be needed

Recumbent Patient Care

• Prolonged recumbency can induce decubital ulcers, tissue necrosis, atelectasis, muscle and ligament contracture, and regional dependent edema

• Passive range of motion should be performed every 4 hours, including the flexion and extension of every joint in the limbs as distal as the phalanges

• ICU-acquired weakness and critical illness neuromyopathy are possible sequelae in long-term ventilation in humans but have not been documented in clinical veterinary medicine

• The position of recumbency should be changed every 4 hours, alternating between sternal and each lateral position, if the patient's oxygenation status will tolerate it

  • If lateral recumbency is not possible, then the patient can be kept in sternal recumbency and the hips of the patient moved from right side down to left side down every 2-4 hours

  • Special attention for ulcer formation at the elbows or for development of dermal lesions in the antebrachium is needed if the cranial half of the patient is always in sternal recumbency

Current Recommendations for Degree of Elevation in Ventilated Patients

• Current recommendation if the patient is ventilated on a table that tilts is to elevate the torso 30-45 degrees

  • Ventilation with the trachea elevated above horizontal is thought to decrease gastroesophageal reflux, whereas ventilation with the trachea below horizontal may prevent aspiration of oropharyngeal secretions into the trachea

  • At this time ventilation with the trachea elevated 45 degrees cannot be recommended in veterinary medicine, at this point patients should be kept in neutral horizontal position

Apparatus Care in the Ventilated Patient

• The ventilator circuit should be sterilized before use and put together wearing sterile gloves to minimize the change of nosocomial infections

• Based on findings, it seems safe to change the circuit if gross contamination is noted rather than as a routine precaution

  • If frequent condensation occurs in the circuit due to use of a heated water humidifier, more frequent circuit changes may be indicated