Respiratory failure is one of the most frequent causes of admission or longer stay in acute care settings. It is usually accompanied by a variety of medical problems, such as stroke and other neurological conditions, cardiovascular disease, and respiratory disorders. Patients with acute respiratory failure require urgent medical attention by the health care team to prevent further deterioration that can eventually lead to mortality. With medical advancement, mortality can be prevented if interventions are quickly and properly provided. Endotracheal tube (ETT) intubation and tracheostomy tube (TT) are the most commonly used advanced artificial airways in managing respiratory failure. Intubated or tracheostomy patients are placed on a mechanical ventilator. These patients are critically ill and require close monitoring by the health care providers and are usually transferred to the intensive care unit (ICU) for further management. The nurses who are providing direct care to patients on mechanical ventilation (MV) carefully assess for signs of respiratory complications such as ventilator-associated pneumonia (VAP). Oral suctioning and tracheal suctioning are crucial nursing interventions to prevent VAP. Hemodynamic changes can also occur during suctioning of these patients. Nurses provide judicious patient care, and they monitor for any changes in the patient's status so they can quickly and accurately respond to any situations that may arise.

BACKGROUND OF MECHANICAL VENTILATION

Artificial Airways

It is important to assess the ability to secure the airway of the patient in managing acute and life-threatening conditions or injuries. Artificial airways such as endotracheal tube and TT are placed when there is compromised ventilation.1

ENDOTRACHEAL TUBE

Endotracheal tube intubation is performed during emergency situations such as acute respiratory failure or inability of the patient to maintain a patent airway. Endotracheal tube intubation requires a cricoid pressure by placing the thumb and the index fingers on the cricoid cartilage. This will compress the esophagus to reduce the risk for gastric aspiration during the intubation.1 The ETT is placed by a qualified provider, and placement is confirmed by a chest radiograph. The ETT balloon should be inflated that is enough to provide a seal and secure the airway, and the pressure should not exceed 15 to 25 mm Hg, which can be measured by using the cuff manometer.1

The internal diameter of the ETT is 8 to 9 mm for men and 7 to 8 mm for women. The end of the inserted ETT is positioned at 2 cm above the carina, the site of tracheal bifurcation.1 Securing the ETT is critical when placement is verified, to prevent from dislodging or moving.1 Endotracheal tube placement is assessed by the nurses and the respiratory therapists (RTs) every shift or in accordance to the hospital protocol.

TRACHEOSTOMY TUBE

A tracheostomy is a surgical opening of the tracheal anterior wall through the neck area. This opening is made at the second or third cartilaginous ring level and is kept patent by inserting a TT. Indications for placing a permanent TT are (a) to maintain the airway because the normal mechanism to maintain the airway has been compromised, (b) to facilitate long-term means of ventilatory support for patients with respiratory failure by MV, (c) elective or emergency surgery for tracheostomy placement for head or neck trauma, and (d) to minimize the risk of aspiration from inability to swallow or absence of the laryngeal reflex.2

The type and size of the TTs depend on the patient's needs, reasons for placement, and the size of the patient's trachea. Tracheostomy tubes can be disposable or nondisposable. Caring for this patient population is based on managing the airway while maintaining the safety of the patients and preventing complications. Patients with a TT are not able to talk or make any sound because the TT is placed beneath the vocal cords. A speaker valve can be used after passing speech therapy evaluation for any risk of aspiration.2 In acute care setting, most patients with TTs have disposable inner cannulas, which are changed every shift and as needed depending on the secretions. For nondisposable TTs, a tracheostomy kit can be used to clean the inner tube. Tracheostomy care is done by the nurses or RTs depending on the hospital policy, and the tracheostomy site should be assessed regularly.

Mechanical Ventilation

Mechanical ventilation is one of the most common interventions in the ICU. It is a supportive intervention used until the underlying physical issue has been resolved. Patients on MV decrease their work of breathing, relieve respiratory distress, rest the fatigued respiratory muscles, improve ventilation, stabilize the chest wall, and restore the acid-base balance.3

Patients on Mechanical Ventilation

Patients on MV have the potential to develop hemodynamic instability. The need for MV is the patient's common feature requiring admission to the ICU.4 Choosing settings for MV requires balance between oxygen delivery, removal of carbon dioxide, and prevention of respiratory injury related to trauma. Inappropriate and inaccurate ventilatory support strategy can result to increase mortality. Therefore, many ventilatory techniques have been presented in standardizing the selection process of the ventilation settings (Table).5

TABLE Modes of Ventilation

Suctioning Type and Routine

Many hospitals have implemented standard order sets and guidelines in managing MV. Respiratory therapists are the experts in providing respiratory care to patients. They have the extensive knowledge on many pathophysiologies that necessitate MV and the pharmacology used in managing ICU patients who are mechanically ventilated. Respiratory therapists are competent in controlling MV settings and are also able to interpret laboratory results and make appropriate adjustments that affect the care of these patients.7 They have the capability to develop and implement guidelines that support the application of MV management. They assess the patients for any deviation and monitor for signs of respiratory distress and are prepared for any sudden change in the patient's respiratory status and apply appropriate and rapid measures in managing potential acute events. Physicians, nurses, RTs, physical therapists, care assistants, and other allied health care personnel work as a team in providing care to these patients.

OPEN SUCTIONING

This requires disconnecting the ETT or TT from the mechanical ventilator, which can result in significant loss of lung volume, and is followed by applying the suction that can further exacerbate the derecruitment of the lungs.8

CLOSED SUCTIONING

Disconnecting the ETT or TT from the mechanical ventilator is not required, allowing for a continued tidal volume delivery and minimize lung volume loss. Closed suctioning is recommended in patients with acute lung injury or acute respiratory distress syndrome because they can have alveolar derecruitment that can be seen during suctioning the patients.8

Suctioning is important in maintaining patency and managing tracheal secretions. Tracheal suctioning can be distressing for the patients and can cause hemodynamic changes such as hypoxemia, arrhythmias, atelectasis, tracheal mucosal injury, bleeding, and infection.2

Mechanical Ventilation and Hospital-Acquired Infection

Ventilator-associated pneumonia is the most common hospital-associated infection in mechanically ventilated patients. Incidence currently ranges from 2 to 22 episodes per 1000 ventilator days. Ventilator-associated pneumonia mean incidence is 2.8 in the United States.9 Ventilator-associated pneumonia is defined as a type of hospital-acquired pneumonia that occurs in patients that are on MV support at the time of the diagnosis of pneumonia or within 48 hours of having been placed on MV.10

Ventilator-associated pneumonia pathogenesis involves aspiration of the bacterial organisms from the oropharynx into the lungs and subsequently causes failure of the defense system of the patients in clearing the bacteria, which leads to the development of a lung infection such as VAP.11

Mechanical ventilation for airway support can be a source of infection. It is an important part in intensive care provision for patients who are acutely and critically ill. Although it is beneficial to patients, it can impair the clearance of mucociliary process, causing retention of secretions, occlusion of the airway, atelectasis, and pneumonia.12 Aspiration of orapharyngeal secretions that are contaminated can lead to the development of VAP. These secretions pool above the TT cuff and eventually enter into the lower respiratory tract through the leaking around the cuff of the TT.9

Ventilator-associated pneumonia can worsen gas exchange, increase the load of secretions, and can potentially lead to deterioration of the function of other body organs such as the heart. Complications can delay the weaning process, prolong hospital stay, and increase mortality, which can result in higher costs of health care. Ventilator-associated pneumonia is associated with increase in morbidity, MV duration, and length and cost of stay in the hospital. Most hospitals have developed clinical preventive care strategies called the "care bundles," which showed effective reduction rate in VAP. Many preventive measures such as oral care routine with an antiseptic solution and elevation of the head of the bed are being implemented to prevent VAP. Chlorhexidine oral decontamination is also a widely researched strategy that can help in preventing VAP.9,13

Ventilator-associated pneumonia prevention is a priority to improve patient care and safety. There is a high morbidity and mortality rate that is associated with VAP and in an effort to address this issue, the Centers for Disease Control and Prevention has developed a guideline for preventing VAP. Ventilator-associated pneumonia bundles were implemented to help reduce the incidence of VAP.14

DIAGNOSIS OF VAP

Ventilator-associated pneumonia is suspected clinically based on the presence of elevated temperature more than 38.3^o C, white blood count more than 10000/mm3 or less than 4000/mm3, purulent secretions, new or persistent pulmonary infiltrate in the chest radiograph, and positive sputum culture and gram stain.10

RESPIRATORY CULTURES

There are many bacterial pathogens that can cause respiratory infections. The major potential respiratory bacterial organisms include Pseudomonas aeruginosa, Staphylococcus aureus, Acinetobacter species, and enteric species.11 A specimen sample from the lower respiratory tract is obtained when VAP is suspected. This involves a specimen collection through suctioning the ETT or TT by using a sterile suction catheter. The specimen is withdrawn and sent to the laboratory for quantitative bacteriology. The presence of more than 10000 colony-forming units per milliliter of target pulmonary respiratory pathogens in minibronchoalveolar lavage fluid or a positive culture is considered to be a positive finding for the diagnosis of VAP.11 As soon as the sputum culture identifies a pathogen and not colonization, specific antibiotic treatment should be initiated.15

CHEST RADIOGRAPH

The presence of pulmonary infiltrates that are not symmetrical on a chest radiograph that is consistent with VAP may be sometimes caused by other noninfectious conditions. However, some chest radiograph findings such as fast cavitation of pulmonary infiltrate that is progressive, air space process that is joining a fissure, bronchogram that is a single air are associated with 96% specific for VAP diagnosis and can be used reliably.10

EVIDENCE PRACTICE REVIEW

The purpose of this study was to determine if the routine method of saline instillation prior to suctioning the mechanically ventilated patients is beneficial or harmful to patients. In addition, our goal was to provide evidence-based practice recommendations that will serve as a guide for nursing and respiratory care practice.

A comprehensive review on the use of saline instillation in suctioning mechanically ventilated adult ICU patients was conducted using databases such as CINAHL, MEDLINE, Cochrane, PsycINFO, and national guidelines for the review of literature. Materials reviewed included only studies of patients 18 years or older, who are intubated or have a tracheostomy in place, requiring MV, and who are admitted in the ICU.

FINDINGS AND RESULTS

Extensive efforts are underway to reduce VAP, which significantly increases the total number of ventilator-dependent days, overall mortality, and medical costs. Evidence-based research studies were analyzed on aspects of caring for the mechanically ventilated patients, including the use of saline installation in general and specialty ICU populations in international settings. Recently, Mei-Yu et al16 conducted an evidence-based research study approach to examine the relationship of saline instillation and VAP in the ICU. Ventilator-associated pneumonia incidence rates were compared between patients receiving normal saline instillation (NSI) and patients who did not receive NSI with ETT suctioning. Data on NSI use were gathered for 6 months and followed by data collection without using NSI. It was found that the VAP incidence rate on NSI use with suctioning is statistically significant. Not using NSI was found to decrease VAP incidence rate significantly.16

This concept is consistent with and supported by earlier work by Hagler and Traver,17 who found that a 5-mL NSI dislodged up to 310000 of viable colonies of bacteria. The potential risk for infection that is caused by dislodging the bacteria into the lower respiratory tract is added evidence that the routine use of NSI when suctioning should not be performed.17

Conversely, Caruso and colleagues18 conducted a randomized clinical trial in a closed medical surgical ICU in a tertiary oncology hospital. Patients were divided into 2 groups. The first group used suctioning without saline (control group), and the second group used 8 mL of isotonic solution instilled prior to each tracheal suctioning (saline group). In this study, the instillation of an isotonic saline prior to tracheal suctioning reduced the occurrence of microbiologically proven VAP. The rates of ETT occlusion and atelectasis were similar between the 2 groups.18

This study prompted debate as Kleinpell19 provided a commentary about Caruso and colleagues' study findings, noting that evidence from a vast number of research studies showed that the routine use of NSI prior to suctioning is not a recommended practice for mechanically ventilated patients. The findings from Caruso and colleagues are significantly different from the results of other studies and must be cautiously interpreted because of a number of limitations, such as the use of an oncology patient population that are different from the general ICU patients with regard to the occurrence of VAP, pretreatment of antibiotics, immunosuppression, and mortality. Kleinpell calls for further research before this practice can be recommended for routine use in ICU patients.

Normal saline instillation in preparation to suctioning the airway is commonly used to help remove thick respiratory secretion; however, Christensen et al20 report that the use of saline can damage the antimicrobial properties of the respiratory secretions. Their findings suggest that nasal and tracheal secretions and saliva have natural antimicrobial properties that can be damaged by instilling concentrations of sodium and chloride in the normal saline.20

Maggiore and colleagues21 discuss the risk for alteration in hemodynamics during suctioning with NSI that may result in complications, mainly oxygen desaturation and bloody secretions. Normal saline instillation can be used in open or closed suctioning and has been used by the health care professionals who believed it would increase the yield of the sputum by diluting and loosening the secretions, stimulate the cough, and lubricate the suction catheter. However, studies are conflicting about the safety and efficacy of using NSI contrary to these common beliefs.22,23

It is believed that it can result to hypoxemia, bronchospasm, cardiac and respiratory arrest, infection, and no improvement in oxygenation or secretion yield.23 A recent systematic review23 aimed to investigate the safety and efficacy of NSI technique prior to airway suctioning. It was found out that there is no evidence that NSI is harmful to the patients based on hemodynamic changes, gas exchange, increased dyspnea, or respiratory distress. Although there was some weak research result linking the use of NSI and VAP, further methodological research studies are warranted.23

Rauen and colleagues24 found in most experimental studies that SPO₂ was significantly decreased with NSI, or there is no difference in SPO₂ with NSI and no saline use. One interesting finding that they found in their systematic review was that there were some indications of a reduction in SPO₂ after NSI prior to suctioning, and the return to baseline SPO₂ levels did not occur until at least 3 to 5 minutes after the suctioning was completed.24

Secretion Production

In regard to secretions, although there is a claimed benefit of NSI in the improved secretion removal, Rauen et al report that there are no adequately reported research studies to support this practice. This is partly due to the problems that are associated with the methodological process with the measuring of the secretion amounts in clinical research studies, which calls for further studies to find out the best way to quantify the amount of secretion removal when using NSI prior to suctioning.24

These recent studies contradict earlier work, in 1990 when Gray et al25 reported that NSI resulted in an enhanced clearance of secretions by stimulating the cough, and the effects on hemodynamics, respiratory mechanisms, exchange of gas, and patient comfort were not significantly different compared to suctioning without NSI. Similar result was reported in a small group of intubated adult patients when NSI was done during chest physiotherapy and resulted in an increased sputum weight and no adverse effects on SPO₂.26

A recent study from the British Journal of Nursing also reports that NSI with suctioning mechanically ventilated patients appears to remove a greater amount of respiratory secretions compared to not using NSI. However, the study cautions that this finding is considered controversial because the increase in weight of the suctioned secretions can be attributed to the NSI.27

Dyspnea

One study in 200128 compared the level of dyspnea with and without using a 5-mL NSI before ET suctioning using a crossover, quasi-experimental study design. Using the vertical visual analogue scale, patients (17 alert adults who are mechanically ventilated) were asked to rank their dyspnea level. Saline was randomly instilled before 1 of 2 suctioning. This study showed no beneficial effects of using saline. However, it demonstrated that NSI precipitated a significant increase in the level of dyspnea up to 10 minutes after suctioning in patients older than 60 years.28

Vital Signs

Maggiore and colleagues found that ET suctioning can cause decrease in SPO₂ by 5%, trauma or bleeding with blood visible in suctioning secretions, increased blood pressure to 200 mm Hg or decreased blood pressure to 80 mm Hg, increased heart rate (HR) to 150 beats/min or decreased HR to 50 beats/min, and arrhythmias such as supraventicular or ventricular tachycardias.21

Iranmanesh and Rafiei29 studied the effect of NSI on the SPO₂, HR, and cardiac rhythm of multiple trauma patients. A crossover design was conducted with 50 multiple trauma patients who were admitted to ICU and were mechanically ventilated for more than 24 hours. Subjects were selected randomly to suctioning with or without the use of NSI. Results indicated that NSI when suctioning can cause potential adverse effects on SPO₂, but results in no effect on the HR or cardiac rhythm. Educational programs should be provided to the nurses and RTs to help improve their knowledge on the disadvantages of using NSI when suctioning an artificial airway.29

Current Guidelines

The national guidelines from the American Association for Respiratory Care30 provide recommendations on ET suctioning. These include (a) suction the ET only when there are secretions present; (b) preoxygenate the patients with decreased SPO₂ when suctioning; (c) do not disconnect the patient from the mechanical ventilator when suctioning; (d) use shallow suctioning than deep suctioning; (e) use closed suctioning for adult patients with high FIO₂ or positive end-expiratory pressure, or those at risk for lung derecruitment; (f) routine use of NSI before ET suctioning is not recommended; and (g) suctioning duration should be limited to less than 15 seconds.30 The Agency for Healthcare Research and Quality updates the current guidelines (the previous version of the American Association for Respiratory Care clinical practice guidelines)31 to include similar recommendations and interventions such as preoxygenation, shallow suctioning technique, sterile technique during open suctioning, using lung recruitment maneuvers, suction duration of less than 15 seconds, and monitoring of the patient.31 It is also noted that deep suctioning and NSI prior to ET suctioning may be considered but are not recommended. The report cautions that NSI is hypothesized to loosen secretions, increase the amount of secretion removal, and help in the removal of tenacious secretions. However, evidence is lacking to support this. The majority of the studies used to update this current guideline indicate that NSI is not likely to be beneficial and may be harmful to the patients. Therefore, NSI with suctioning is not recommended to be routinely performed, and the potential danger of the routine use of NSI may be associated with adverse events such as excessive coughing, decreased SPO₂, bronchospasm, tachycardia, pain and dyspnea, and increased intracranial pressure.31

The guidelines on routine practice of suctioning mechanically ventilated patients are not consistent with routine use of saline instillation, as the efficacy of NSI is not supported by research-based evidence. This practice may provide no physiological benefits and may have effects that can be detrimental.32 However, NSI continues to be used in practice and requires additional study to establish its safety and effectiveness. Although the use of NSI is a routine clinical practice in some ICUs, its negative effects and questionable benefits on the amount of suctioned secretions should encourage the nurses or RTs to not apply this technique and reconsider the practice and should not be a routine method in suctioning patients with an artificial airway for removal of respiratory secretions.27

Maggiore and colleagues21 follow clinical guidelines for ETT suctioning, as the use of NSI is avoided. They recommend a heated humidifier for patients with dry and tenacious secretions. If mucous plug is suspected, suctioning under the direct visualization of fiberoptic bronchoscopy should be performed.21

Rauen and colleagues24 also support these national guidelines and report that recent evidence provides a unanimous recommendation that NSI should not be a routine practice with suctioning.

CONCLUSION AND RECOMMENDATIONS

Patients on MV are at high risk for many complications such as infection (ie, VAP) and hemodynamic changes. Clinical routine practice of NSI with suctioning an artificial airway is being done on a daily basis without having a clear evidence-based clinical guideline to support its practice. This can cause many potential complications especially to those patients who are already critical or unstable in terms of their medical conditions. This study found out that suctioning an artificial airway with the use NSI can pose great risks to the patients. It can cause complications such as VAP and hemodynamic changes that are not favorable to the patients' recovering process. This review does not endorse the use of NSI when suctioning a patient with an artificial airway. Education should be provided to every health care provider regarding the effects of using NSI when suctioning and how it can cause further harm to the patients. It is prudent advice from researchers such as Rauen and colleagues, who reminds us that there is no credible and scientific research information that supports this practice. There are no known studies that have shown that NSI is beneficial, and in addition to its lack of theoretical benefits, researchers found it to be detrimental to the patients.24

Implementing clinical guidelines is crucial in order to maintain the safety of all patients. Although most of the evidence suggests not to use NSI when suctioning, there are various limitations to the studies done such as small sample size, settings, inconsistencies in data collection, or not enough or outdated research clinical trials, which calls for further research studies. Therefore, extensive clinical trials are recommended to effectively determine if NSI with suctioning an artificial airway is indeed harmful, and adherence to national clinical guidelines should be strictly enforced nationwide for all hospitals to include in their standardized protocol to not use NSI with suctioning.

Acknowledgments

I would like to extend my deepest gratitude to all the people who have helped me with this paper. First, I would like to thank my professor, Dr Thomas Barkley, for being a great mentor and an advocate for ACNP students. Thank you for helping me structure my research topic and for guiding me with writing this article. I would like to thank my clinical instructor, Alison Forbes, ACNP, who served as my advisor, assisting me with the revision and provided comments on how to better organize my article. I would also like to thank Kevin Quinonez, RT, for being an expert with regard to respiratory care and provided his professional and own personal stance about the article. Lastly, I would like to express my warmest appreciation to the editor-in-chief of the DCCN journal, Kathleen Ahern Gould, PhD, RN, for the professional feedback and the guidance to make this article possible.

References