Ventilator Safety

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Josh Leidich
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By: Lesley M. Williams and Sandeep Sharma
Published: National Center for Biotechnology Information, U.S. National Library of Medicine
Date: Latest update – August 11, 2021

For safety, certain key features of mechanical ventilation are vital.[1][2][3] These include the following actions: 

1. Communicate: Patients on mechanical ventilators are usually looked after by an interprofessional group of healthcare professionals that may include an intensivist, critical care nurse, nutritionist, infectious disease consult, respiratory therapist, primary care physician, and a pulmonologist. For the patient to receive optimal care, communication between each other is vital. The goals of treatment regarding ventilation should be made known to everyone. One professional should not start weaning or change any ventilatory status empirically but speak to all the relevant specialists first, especially the respiratory therapist. In some cases, ventilation may only be required because the patient is on an intra-aortic balloon pump. This invasive therapy is not comfortable and requires ventilation until cardiovascular stability is obtained. Premature extubation can cause great discomfort to the patient, who may also start to move and disturb the functioning of the balloon pump. Furthermore, just because the patient is on the ventilator, it does not mean that he or she cannot hear or understand communication. While they may not be able to speak because of the endotracheal tube, a patient may be able to communicate if provided with a piece of paper and pen. It is also inappropriate to say anything negative or deleterious about the patient on the ventilator. There should be open communication between the physician, nurse, and respiratory therapist to ensure that the ventilated patient is safe.

2. Check ventilator settings: When first entering the room of a patient on a ventilator, check their vital signs, including pulse oximetry and the last arterial blood gas. Auscultate the chest and determine if there are any significant changes from the previous nursing shift. Assess the patient for comfort, distress, pain, and hemodynamic stability. Next, check the ventilator settings and the parameters. Review the last order on the ventilator settings and see if they are the same ones on the ventilator.[4]

3. Ventilator management and respiratory therapist: The individual who is best suited to manage, adjust, and document the ventilator is the respiratory therapist. Secondly, to provide safe care to ventilated patients, the number of healthcare professionals who are allowed to make adjustments to the ventilator should be limited. All respiratory therapists, by their training and daily experience, have significantly more experience and clinical competence than most healthcare professionals when it comes to the ventilator. Every time an adjustment is made on the ventilator, the respiratory therapist must be notified so that the alarm settings can be reviewed and adjusted as needed for the safety of the patient. Any healthcare worker who makes changes to the ventilator settings must be able to demonstrate the same degree of competency and training as that of a respiratory therapist.

4. Alarms: All ventilators have alarm hush sounds when there is any change in ventilation. A ventilator alarm should never be ignored or silenced without first checking the problem. It is vital to know what to do when an alarm sounds on the ventilator. The respiratory therapist, along with the units medical director, is responsible for developing policies and procedures on the use of ventilators and management of alarms. It is vital that the alarms be set appropriately; otherwise, there is potential for significant morbidity and mortality. Most hospitals have an interprofessional team that establishes alarm policies and directives regarding permission to modify them. Any healthcare worker who wants to alter the parameters on the mechanical ventilator must first demonstrate the same level of competency as that of a respiratory therapist. All ventilator alarm management policies should include:

  • Alarm functionality tests and what they mean
  • Associated competence tests on what to do when an alarm sounds
  • How to extract alarm data
  • How to modify alarms
  • Manufacturer-specific alarm setting requirements
  • Reporting procedures to improve clinical practice
  • Sounds associated with various alarms
  • Who is allowed to change alarm settings

Every effort should be made to create a safe patient environment where good clinical practice flows and nuisance alarm calls are minimized. Two key points to know when setting the ventilator alarms are that these devices are both protective and informative. Setting limits on rate, pressure, and volume is just as important as the ventilator settings. Many healthcare institutions have established policies that require alarm settings to be set at a specific percentage of the ventilator settings, and these should not be changed arbitrarily.[5]

5. Bag valve and mask: Every patient on a ventilator must have a bag valve and mask located on the wall. This bag must be checked every day to make sure it is in working order. When an alarm sounds on the ventilator, if the patient self-extubates, when there is patient-ventilator dyssynchrony preventing the patient from getting effective ventilation and oxygenation, when the endotracheal tube is dislodged, a bag valve mask is required to oxygenate the patient manually until he or she is reintubated. Always practice ventilation with a bag-valve-mask because it is a skill that will be required when looking after patients on the ventilator.

6. Ventilator settings: The latest ventilators are sophisticated machines, and each one has a slightly different setup, but medical professionals still have to know some basic details about the equipment. When assessing a patient on a ventilator, start in standardized sequence as follows:

  • Check the respiratory rate per minute. The machine will highlight the number on the screen. Manually count the patient’s respiratory rate and determine if he or she is breathing at a rate above the ventilator setting.
  • The ventilator will also highlight the fraction of inspired oxygen. In a freshly intubated patient, this is usually 100%, and then it can be weaned down based upon the Po2 on the ABG or merely following the pulse oximetry. 
  • Check the tidal volume, which is the volume of air inhaled at each breath expressed in milliliters. The tidal volume is about 6-8 mL/kg of ideal body weight for patients with healthy lungs. For unhealthy lungs, such as in ARDS  or ALI,  4-6 mL/kg is used as a protection strategy for the lungs. For example, the set tidal volume for a patient whose height is 5 feet 10 inches and weighs 400 pounds (180 kg) will be the same as for a patient with the same height but weighs 180 pounds (84 kg).
  • Peak inspiratory pressure is the highest pressure needed to provide each breath during inhalation. In general, this is usually kept below 40 cmH2O. Peak inspiratory pressures increase with increased resistance. If the peak inspiratory pressure is high, the machine will sound an alarm. It could be that the endotracheal tube is kinked, or the patient is biting down on the tube. It can also mean a mucus plug, bronchospasm, or a sudden pneumothorax.
  • Plateau pressure is pressure applied to the alveoli during positive pressure ventilation. This is measured during a breath-hold when there is no gas exchange occurring. This pressure should be below 30 cm H20. High plateau pressures indicate a problem with compliance of the lungs, such as in ARDS, restrictive diseases, or even obesity.
  • Positive end-expiratory pressure (PEEP) is the pressure at the end of expiration. This is usually used to improve oxygenation. With positive end-expiratory pressure, a small amount of continuous pressure (generally from 5 to 8 cmH2O) is added to the airway to increase the effectiveness of oxygenation. In many cases, positive end-expiratory pressure is added to reduce oxygen requirements. In patients with acute respiratory distress syndrome, it is usually set at 10 cmH2O or higher. Patients with bronchospasm due to acute exacerbation of asthma and COPD can develop AUTO- PEEP, which can result in higher positive end-expiratory pressure can be associated with a pneumothorax due to barotrauma. One must be very vigilant about a tension pneumothorax on a ventilated patient as it can quickly drop the blood pressure and result in respiratory arrest. [6]

7. Modes of ventilation: The mode of ventilation will usually depend on many patient variables. The usual modes of ventilation include:

  • Assist control is where the ventilator delivers preset breaths in coordination with the respiratory effort made by the patient. With every inspiratory effort, the ventilator will deliver a full assisted tidal volume. In this mode of ventilation, spontaneous breathing is permitted. This mode of ventilation is primarily used for patients who are too weak to take spontaneous breaths, as the ventilator will deliver a set amount of tidal volume and respiratory rate. The disadvantage of this mode of ventilation is that it delivers a set tidal volume and flow, which can lead to patient discomfort and can lead to patient-ventilator dyssynchrony. This can lead to breathing stacking and auto-PEEP. Auto-PEEP development can lead to ineffective oxygenation, ventilation, and hemodynamic instability. Assist control is typically used for patients that have just been resuscitated, heavily sedated, or have acute respiratory distress syndrome.[7]
  • Controlled mechanical ventilation is where the machine delivers a set tidal volume and respiration rate. The ventilator does all the work, and the patient needs to be paralyzed or heavily sedated. The disadvantage is that this mode does not permit normal spontaneous breathing and can lead to patient-ventilator dyssynchrony if not paralyzed. In this mode, the patient cannot adjust to the PaC02 demand. In the long run, this mode of ventilation can cause atrophy of respiratory muscles. This mode of ventilation should not be used outside of the OR.
  • Synchronized intermittent mandatory ventilation delivers a preset number of breaths in coordination with the respiratory effort of the patient, but permits spontaneous breathing. The advantage of this mode of ventilation is that it allows the respiratory muscles to work and can improve cardiac output. The disadvantage is that it may cause respiratory acidosis and fatigue of the patient’s respiratory muscles. This mode of ventilation can be used for the weaning process but has shown to be inferior to pressure support for weaning the patients off the ventilator. [8]
  • Intermittent mandatory ventilation is where the machine delivers a set tidal volume at a fixed rate at the lowest setting to support and maintain an appropriate arterial blood gas. The ventilator will deliver a set tidal volume regardless of effort by the patient. This mode of ventilation permits the patient to do some breathing and is less likely to produce barotrauma. However, the disadvantage is that it can cause stacking of breaths, which can result in barotrauma if the ventilator peak inspiratory pressure is not set appropriately.[9]
  • Pressure-supported ventilation is used to decrease the work of breathing and limit barotrauma. It differs from synchronized intermittent mandatory ventilation and assists control in that the level of support pressure is set to assist every spontaneous effort made by the patient. The benefit of pressure support ventilation is that it can improve oxygenation and lower the work of breathing. The disadvantage is that there is no guarantee for volume, especially when the mechanics of the lung are changing. This mode of ventilation has often been used to manage patients who have neuromuscular disorders but normal lungs. It is also used for weaning patients from mechanical ventilation.[10]
  • Continuous positive airway pressure(CPAP) is not considered a mode of ventilation. Continuous positive pressure is applied to a spontaneously breathing patient, and the patient is responsible for initiating and sustaining the breathing process. Respiratory rate and tidal volume depend on the patient’s inspiratory efforts without the help of the ventilator. This mode can tire the patient, so they must be closely monitored.[11]

8. Carbon dioxide detectors: The use of CO2 monitors has become routine in most intensive care units.There are several types of monitors. The most basic is the colorimetric monitors work by indicating a color change of the device when CO2 is present. This is often used in emergency settings to verify ETT placement as they are small portable devices. Capnography displays a waveform graph of exhaled CO2 while a capnometer only displays a number. These are usually used in conjugation with each other and often used interchangeably. Both devices are complex equipment. These devices can detect and/or measure the amount of exhaled carbon dioxide and are frequently used for three conditions:

  • Confirm placement of the endotracheal tube in the trachea
  • Monitor patient during mechanical ventilation
  • Monitor ventilation during procedural sedation without mechanical ventilation

In the intensive care unit the capnograph/capnometer can be used on ventilated patients for different reasons, including the following:

  • Alarm for airway disconnection
  • Dislodgement of the endotracheal tube
  • Recognition of different waveforms which may indicate bronchospasm, kinking, or mucus plug
  • Assess the quality of CPR
  • Recognize spontaneous breathing during apnea testing
  • Protect against any unexplained PCO2 in neurosurgical patients
  • A sudden drop may indicate a drop in pulmonary blood flow and suggest a pulmonary embolism

The capnography provides a visual display of exhaled carbon dioxide with time and also produces a waveform. Increased end-tidal carbon dioxide may be due to:

  • Cardiogenic shock
  • Cardiac arrest
  • High ventilation/perfusion lung scan ratios
  • Use of positive end-expiratory pressure
  • Inaccurate calibration of the capnometer[12]

9. Ventilator initiation: All manufacturers of ventilators highly recommend a pre-operational check prior to the use of the ventilator on a patient. This precheck is designed to check the integrity of the ventilator circuit, confirm the functioning of the components, the humidifier system, and tubing. The precheck is usually done at the time of the humidifier or circuit set up. In addition, any time the circuit is changed or modified, a precheck must be done. When the machine is first powered on, some of the ventilators will reset to the default settings predetermined by the manufacturer, while other ventilators will default to the last operational settings. The default settings may not be ideal for some patients and pose a risk. Most critical care units use ventilator protocols based on patient disease, which helps lower the risk of barotrauma by utilizing strategies to protect the lung. Thus when initiating ventilation on a patient, it is important to know the patient’s medical history, the reason for mechanical assistance, patient airway anatomy, and the eventual goal. All of these factors help determine ventilator settings.

10. Suctioning of ventilated patients: In general, all ventilated patients need regular suctioning. Since these patients are not able to expectorate their secretions which often collect in the airways, become viscous, and lead to respiratory distress. When suctioning patients on a ventilator, look at the patient, and listen to the chest. If it is clear and has no distress, suctioning is not required. Suctioning is based on need and should not be performed on a schedule. If suctioning is appropriate, hyper-oxygenate the patient for a few minutes before initiating suctioning. This is vital since suctioning can quickly lead to hypoxia. The suctioning procedure should only last for 10 seconds and pay attention to the pulse oximetry. Bradycardia may occur due to a vaso-vagal response. Discontinuing the procedure will usually return the patient to baseline. If the patient stays bradycardic, atropine can be used. Normal saline or any other liquid should not be instilled in the endotracheal tube before suctioning. Use the lowest suction pressure to remove the secretion. Too much pressure can lead to damage to the mucosal surface of the airways.

11. Check the position of the endotracheal tube: During the initial survey of the intubated patient, the position of the endotracheal tube must be checked to ensure that it has not slipped into the right mainstem bronchus. In some cases, the endotracheal tube may be pulled up. The chest should be auscultated for equal breath sounds, and then the length of the endotracheal tube inserted should be checked. In male patients, the endotracheal tube is usually inserted at a distance of 22 to 24 cm, and in female patients, it is between 20 and 22 cm. However, the most recent chest X-ray must also be reviewed to look at the position of the endotracheal tube and for the presence of any pneumothorax or lung collapse. The endotracheal tube should generally be placed 3 to 4 cm above the carina.

12. Sedation: Having an endotracheal tube is very uncomfortable, and most patients require some sedation. Thus, the patient should be assessed for pain and anxiety. The sedation level of the patient can be assessed by the Ramsay sedation and the Richmond agitation sedation scales. When an intubated patient is agitated, the risk of self-extubation is very high. Therefore, it is best to sedate the patient if the individual is not ready to be weaned.[13]

13. Infection prevention: One problem with mechanical ventilation is the development of pneumonia. Ventilator-associated pneumonia is not uncommon, and it adds significant morbidity to the patient. Guidelines to prevent ventilator-associated pneumonia include the following:

  • Maintain the head of the bed elevation between 30 and 45 degrees if there are no contraindications.
  • Assess the patient daily for readiness to extubate and give a break from sedation- sedation vacation. This also depends on the vital signs, arterial blood gas, and hemodynamic instability. Assess the patient’s own ability to breathe. The shorter the time on the ventilator, the lower the risk of ventilator-associated pneumonia.
  • All patients on the ventilator need to have prophylaxis against peptic ulcer disease. Use a proton pump inhibitor or a histamine 2-blocker.
  • All patients on a mechanical ventilator should receive deep vein thrombosis prophylaxis. The use of either heparin and/or sequential compression stockings may be appropriate.
  • Oral cavity hygiene should be maintained.  This may not always be possible because the endotracheal tube may not allow for meticulous cleaning at the back of the throat. However, the teeth should be brushed, and the mouth should regularly be rinsed. The use of chlorhexidine has been the standard of care for many years. Newer studies have shown no impact on the rate of ventilator-associated pneumonia, length of ICU stay, or time of mechanical ventilation.[14]
  • Perform passive range of motions to avoid contractures; turn and reposition the patient to prevent muscle disuse and pressure sores. Having the patient sit up helps in improving lung compliance and gas exchange.
  • Provide enteral nutrition if the patient has a functioning gut, and there are no contraindications. Nutrition prevents a catabolic state and also helps build up the immune system.
  • Suction any visible secretions and provide good oral care.[15]

14. Hemodynamic stability: Patients on a ventilator need their respiratory and cardiac status monitored closely. Most intensive care units monitor continuous pulse oximetry and blood pressure. By maintaining stable hemodynamics, this also increases tissue perfusion and enables early extubation. To maintain stable hemodynamics, some patients may need continuous intravenous fluids, and others may require the use of pressor drugs like norepinephrine.

15. Check the cuff pressure: Increased cuff pressure can lead to necrosis and stricture formation of the trachea. Thus all hospitals have a policy on how much cuff pressure should be used. The endotracheal tube cuff pressure must be in a range that ensures the delivery of prescribed tidal volume and decreases the risk for aspiration of upper airway secretions that accumulate above the cuff without compromising perfusion of the trachea. A cuff pressure of 20 to 30 cmH2O is recommended for the prevention of ventilator-associated pneumonia and aspiration.

16. Nutritional needs: Most patients on a mechanical ventilator are rapidly extubated, and nutrition is generally started within 24 to 48 hours after intubation. If the patient cannot be weaned off from the ventilator in 14 to 18 days and requires a tracheostomy tube for prolonged ventilatory support, a percutaneous gastrostomy tube (PEG) should be inserted at the same time for meeting the nutritional goals. Total parenteral nutrition should be avoided unless the patient has a nonfunctioning gut. Unless and until the patient is malnourished, the TPN is started after 7 days.

17. Weaning: At some point, the patient’s ability to come off the ventilator should be assessed. This can only be done if the patient is hemodynamically stable, not having active MI, not going through delirium tremens, his or her arterial blood gas is near normal limits, and the patient is tolerating 50% and below FIO2 and positive end-expiratory pressure of 8 and below. A patient can be weaned in many ways, and each intensive care unit has its own protocol. The main concern is to ensure that the patient is alert and stable and that the respiratory therapist is available. Some patients may be weaned over a few days, and others may be weaned over a few weeks. Some patients may not be weaned off the ventilator and require a tracheostomy.[10]

18. Ventilator failure: Every healthcare institution and long-term nursing home which uses ventilators must have a backup plan for ventilation in case of a power failure. In the event of a natural disaster, the institution may also require a generator to power the machine. If the ventilator itself fails, a backup must be available. A backup ventilator should also be available in the home of a ventilated patient who resides more than 2 hours away from a healthcare institution. Additionally, a plan should be developed, which allows for communication between the patient or caregiver and the physician on how to manage equipment failure.

19. Documentation: With the introduction of electronic health reporting (EHR), patient information may be shared across the continuum of care both at the bedside and through remote access. Thus, all ventilatory parameters should be entered in EHR with the time and date. Some ventilators are electronically integrated with EHR, the pharmacy, and medication delivery systems. This integration allows the pharmacist and the laboratory to document relevant information and prepare any needed medications. Any change in the ventilatory parameters must be entered into EHR, which makes it easier to implement many aspects of respiratory care. EHR orders allow collaboration between physicians, nurses, and respiratory therapists in real-time. With rapidly accessible EHR, patient care can be standardized.

20. Guidelines and Protocols: A committee with the medical director and respiratory therapist should help set up the protocols and guidelines for treatment. No matter what protocol is established, interprofessional communication is vital when looking after a ventilated patient. Even the Joint Commission mandates having standards regarding the care coordination of ventilated patients. The hospital must establish a process of handing off or sharing of information with the new shift provider caring for the patient. An interprofessional round should be conducted to ensure that the entire team knows about ventilated patients. Further, end of shift rounds should also be done to provide information to the oncoming shift of nurses and respiratory therapists.[16][17][18]

21. The patient’s family: For most families, it is frightening when a patient is on a ventilator. Most people think that when a patient is on a ventilator, it is a terminal event. Thus, education is needed to teach the family why ventilation is required and emphasize the fact that most patients are weaned off within a few days. Reinforce the need for multiple assessments like chest X-ray and arterial blood gases. Let the family passively participate in the patient’s care by massaging the extremities, holding hands, or speaking to the patient.

22. Competency and education: Mechanical ventilation of patients is a complex endeavor. Because there are several types of machines and models, it is important to regularly educate all the relevant personnel on the basic features of the machines. All staff who care for ventilated patients must demonstrate competency; their knowledge and skills must be documented on a variety of ventilator settings. Almost all respiratory and pulmonary boards recommend regular competency evaluations of all providers of this invasive technique. Competencies required of respiratory therapists and critical care staff with regards to mechanical ventilation include all the technical aspects of the mechanical ventilator, including the following:

  • Bedside monitoring
  • Complications of mechanical ventilation
  • Effective communication
  • Evidence-based application of mechanical ventilation
  • Independent application of mechanical ventilation
  • Indications for mechanical ventilation
  • Initiating ventilation
  • Management of the airway
  • Mechanical ventilation adjuncts
  • Modes of mechanical ventilation
  • Monitoring
  • Noninvasive ventilation
  • Pathophysiology of lung disorders that require ventilation
  • Patient-ventilator interactions
  • Pharmacology of critical care
  • Protocols and guidelines
  • Respiratory physiology
  • Weaning and extubation

Source: https://www.ncbi.nlm.nih.gov/books/NBK526044/
Image: https://i.guim.co.uk/img/media/60bba82aaeedb75bb5d1d50e51f5e64283ae491a/0_325_4879_2928/master/4879.jpg?width=445&quality=45&auto=format&fit=max&dpr=2&s=21baed785ce44a9e9ca8687e2edf7b04

Analysis:

As this is an extensive article pertaining to ventilator safety, the purpose is to cover, in detail, all the features and actions that a mechanical ventilator performs. In addition, outlined are specific functions of the ventilator and how they operate in relation to the patient. In correspondence with the patient, there is provided information that explains how such individuals will be feeling and the necessities they will require while on a ventilator. These specifics are details that can not be overlooked and must be accounted for when identifying the user-interface and experience when connected to a ventilator. Not only should a ventilator serve as provided data to the healthcare workers, but the patient should also be aware and understand the modes, settings, and information that pertain to their well-being. Furthermore, the user-experience of a patient on a ventilator is not limited to the machines, yet the surrounding environment that includes the travel path that is to be taken when transported. This articles give a detailed overview of the implementation of a ventilator, and such information can be applied when identifying pain-points and issues that may arise at certain steps of the process generating a focus for my design.

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