AARC Clinical Practice Guidelines: Artificial Airway Suctioning

Indications for and Complications of Artificial Airway Suctioning

Retained tracheobronchial secretions are common in patients with an artificial airway. It is important for the caregiver to recognize when suctioning is warranted as well as the potential complications and hazards. A review of the literature yielded 27 relevant studies.^2,4,7-31

Routine Versus As-Needed Only Artificial Airway Suctioning

The frequency at which to perform artificial airway suctioning remains controversial. A review of the literature yielded 2 studies^32,33 related to frequency of suctioning: one study each in neonatal and pediatric patient populations. In a randomized, controlled trial of 180 very low birthweight neonates randomized to artificial airway suctioning every 4 h or every 8 h, plus as needed, Cordero et al³² found no difference in mechanical ventilation days, hospital LOS, bloodstream infections, ventilator-associated pneumonia (VAP), or adverse events between the groups. In a randomized controlled trial of 90 pediatric subjects randomized to artificial airway suctioning either every 2 h or as-needed only, Lema-Zuluaga et al³³ showed no difference in VAP, mechanical ventilation days, ICU LOS, or mortality between the 2 groups. No studies were found that addressed suctioning frequency in the adult patient population. Based on the evidence presented in these studies, as-needed suctioning is just as effective as routine suctioning and does not increase morbidity or mortality in neonatal and pediatric populations. The current evidence supports the previous recommendation advanced in the 2010 AARC CPG¹ to perform airway suctioning of the artificial airway only as needed (evidence level B, all the committee members rated the appropriateness score at 8).

Open Versus Closed System Artificial Airway Suctioning

Since the development of closed suction system devices in the early 1990s, researchers have sought to compare the resultant clinical outcomes with those of the traditional open suction system. This systematic review included 28 studies^22,27,34-59 focused on relevant clinical outcomes that compared closed suction system with the open suction system. The majority of the studies^{22,27,36,39-46,48,49,51,52} included physiologic outcomes and the development of hospital-acquired infections. Two studies^34,35 that compared the closed suction system with the open suction system focused on secretion management. Witmer et al³⁴ studied adult subjects who were intubated. They compared the quantity of secretions removed during artificial airway suctioning and found that secretions removed via closed suction system (median 1.7 g) and the quantity removed via the open suction system (median 1.9 g) (P = .88) were not statistically different.³⁴ Lasocki et al³⁵ studied the effects of the closed suction system and the open suction system on secretion removal in 9 adult subjects who were intubated. They discovered that the mean aspirate mass was larger with the open suction system (mean 3.2 g) than with the closed suction system (mean 0.6 g) (P = .03).³⁵ The small sample size of this latter study raises concern about the generalizability of this finding.

Several studies^{22,27,36,39-46,48,49,51,52} evaluated changes in physiologic parameters in response to the closed suction system and the open suction system. Studies that enrolled adult subjects focused on parameters such as heart rate, breathing frequency, , pain, agitation, cardiac dysrhythmias, and ICP.^22,27,36-42 Most of these studies found no significant difference in the outcomes between the closed suction system or the open suction system, although some studies^35,43,44 did see some minor differences. Johnson et al⁴³ noted that the closed suction system had fewer physiologic disturbances (heart rate, blood pressure, , dysrhythmias) than the open suction system. Lasocki et al³⁵ noted that oxygenation and ventilation were better maintained with the closed suction system. Uğraş and Aksoy⁴⁴ found that the closed suction system had less impact on ICP during and after the suctioning event and less impact on the mean arterial pressure during the suctioning event than with the open suction system.

Several pediatric and neonatal studies focused on physiologic parameters as well.^45-52 Changes after suctioning with the closed suction system or the open suction system were similar to those found in the adult studies and likely transient. Evans et al⁴⁸ found a lower incidence of physiologic disturbances (heart rate, , mean arterial pressure) with the closed suction system than with the open suction system. Kalyn et al⁴⁹ noted that there was less physiologic instability with the closed suction system than with the open suction system.

Most of the outcome-oriented studies that compared open with closed suctioning focused on rates of bacterial colonization and VAP/ventilator associated events (VAE). The majority of these studies were in adult subjects, although a few studies included neonatal and pediatric subjects.^{37,42,50,53-59} Cordero et al⁵³ compared infection rates with the use of the closed suction system and the open suction system in neonates. They found that the difference in rates of airway colonization and nosocomial pneumonia were not statistically different between the 2 methods.⁵³ Morrow et al⁵⁰ performed an 8-month study that compared various outcomes of the closed suction system versus the open suction system in pediatric subjects who were intubated and who received mechanical ventilation for > 24 h. The rate of VAP was not statistically different between the 2 methods (P = .6).⁵⁰

Almost all of the studies that focused on adults who were intubated^37,42,53-59 found no statistically significant differences in VAP/ventilator associated event rates, colonization rates, transmission rates, or rates of hospital-acquired infection. One study⁵⁶ did find a difference in colonization rate between the closed suction system (67%) and the open suction system (39%) (P < .02) but that did not translate into an increased number of infections. One study looked at the rates of mucus plugging between the 2 suction methods. Åkerman et al³⁷ found more occurrences of ETT occlusion with the closed suction system but not at a statistically significant level.

Of the 28 included studies for this research question, 5 studied the impact of the closed suction system and the open suction system on outcomes related to mortality, hospital and ICU LOS, and time spent on mechanical ventilation.^{37,42,50,55,58} Four of the studies included adult subjects who were intubated.^37,42,55,58 None of these studies showed a statistical difference between the closed suction system and the open suction system on mortality, hospital LOS, ICU LOS, or duration of mechanical ventilation. Morrow et al,⁵⁰ as previously discussed, found the same results: no statistical difference in mortality, hospital LOS, ICU LOS, or duration of mechanical ventilation.

Based on the quantity and quality of the included evidence, either the closed suction system or the open suction system can be used safely and effectively to remove secretions from the adult patient with an artificial airway. Although the differences in outcomes between the closed suction system and the open suction system in pediatric and neonatal patients are minimal, using a closed suction system with this population is logical. The clinician is urged to use appropriate infection control measures and safety precautions to avoid unnecessary adverse reactions, such as physiologic changes and damage to the airway mucosa (evidence level B, median appropriateness score 8.3, range 7–9).

Preprocedure Oxygenation and Hyperoxygenation for Artificial Airway Suctioning

Artificial airway suctioning may cause a clinically important decrease in oxygenation in some patients. A review of the available literature on hyperoxygenation before suctioning yielded 6 studies^39,60-64 with 3 of these being published in the 1990s.^60-62 In a randomized crossover trial with 25 pediatric subjects on mechanical ventilation, Kerem et al⁶⁰ found that preoxygenation with 100% oxygen prevented hypoxemia during suctioning, whereas hyperinflation by using baseline did not. Lookinland and Appel⁶¹ obtained similar results in an adult population. Preusser et al⁶² conducted a randomized crossover trial with 10 adult subjects on mechanical ventilation by using 1 of 2 lung volumes at 1.0 with the ventilator or manual resuscitation bag. There was no statistically significant difference in , mean arterial pressure, or cardiac output between any of the 4 combinations, but peak airway pressure was significantly greater (P < .001) with the manual resuscitation bag. de Freitas Vianna et al⁶³ conducted a prospective crossover study of 68 adult subjects who were preoxygenated with 1.0 and 0.2 above baseline. No difference was found in , heart rate, mean arterial pressure, or breathing frequency before or after suctioning. A prospective crossover trial of 30 adult subjects conducted by Demir and Dramali⁶⁴ found significant decreases in and but not heart rate or mean arterial pressure, after artificial airway suctioning without preoxygenation compared with preoxygenation with 100% oxygen.

Although the evidence supports preoxygenation, it seems that 100% oxygen is not required for all patients. The 2010 AARC CPG¹ recommended using 100% oxygen to preoxygenate adult and pediatric patients before suctioning either by manually adjusting the oxygen or by using the temporary preoxygenation program on the ventilator. Manual ventilation to provide preoxygenation was not recommended. There is currently available evidence that these recommendations are appropriate, although preoxygenation with an 0.2 above baseline, rather than an increase to 1.0, may be sufficient in adult and pediatric patients. No evidence was available with regard to preoxygenation in the neonatal population (evidence level B, all the committee members rated the appropriateness score at 9).

Normal Saline Solution Lavage for Artificial Airway Suctioning

There has been considerable research on the effects of using normal saline solution during artificial airway suctioning. The theoretical advantages of using normal saline solution are loosening secretions and increasing the volume of secretions removed during suctioning.¹ A review of the literature yielded 8 studies that focused on the impact of normal saline solution use during artificial airway suctioning on oxygenation.^65-72 Results of 7 of these studies suggest that normal saline solution may negatively affect oxygenation. These studies were small, but indicated that measures such as , , and may be unfavorably impacted by artificial airway suctioning,^65,67,69-72 even when other physiologic measures such as heart rate and blood pressure are not impacted.⁶⁶ Normal saline solution use during artificial airway suctioning has also been shown to increase dyspnea in patients ≥ 60 years of age.⁷³

McKinley et al⁷⁴ performed a randomized trial to evaluate the hours of intubation and invasive mechanical ventilation in pediatric subjects. They found that using no saline solution was as effective as using quarter-normal or normal saline solution.⁷⁴ In a prospective observational study, Owen et al⁷¹ noted more adverse events in pediatric subjects who received normal saline solution during suctioning events. A randomized clinical trial by Caruso et al⁷⁵ noted a decrease in microbiologically proven VAP with the use of normal saline solution during artificial airway suctioning. Although this finding is interesting, it has not been corroborated in another study to this point.

The 2010 AARC CPG¹ recommended against the routine use of normal saline solution. Since that guideline, no new evidence convincingly impacts that recommendation. Normal saline solution instillation, if ever performed, should be done so sparingly and with consideration of the potential for adverse events, such as a decrease in oxygen saturation, excessive coughing, bronchospasm, tachycardia, dyspnea, an increase in ICP, and the dislodgement of bacterial biofilm on the inside of the artificial airway. Based on the currently available evidence, it seems that the routine use of normal saline solution is unnecessary during artificial airway suctioning (evidence level B, median appropriateness score 9, range 8–9).

Clean Versus Sterile Artificial Airway Suctioning Procedure

As previously discussed, both the open suction system and closed suction system procedures can be used safely and effectively to remove secretions from an artificial airway. When performing an open artificial airway suctioning procedure, the clinician must maintain an environment that protects both the patient and the clinician from pathogens. However, questions arise with regard to whether the procedure should be a clean procedure, one that is free from visually obvious contamination, or a sterile procedure, one that is free from bacteria or microorganisms. Some clinicians argue that the sterility of the clinician is irrelevant because the open suction catheter will pass through a non-sterile field, and subsequent passes of the catheter will no longer be sterile.⁷⁶

This systematic review of the literature found no studies focused on patient outcomes when comparing the clean versus sterile open suctioning procedure. Past CPG¹ have evaluated this research question. The Centers for Disease Control and Prevention 2003 Guidelines for Preventing Health-Care Associated Pneumonia⁷⁷ recognized that tracheal suctioning does increase the opportunity for cross-contamination and that the risk of cross-contamination can be reduced by using an aseptic (sterile) technique. However, the committee was unable to make a recommendation for using a sterile rather than a clean technique when performing endotracheal suctioning. The 2010 AARC CPG¹ was also unable to make a recommendation, although it did state that the clinician is encouraged to use the sterile technique throughout the suctioning procedure.

There is a gap in the literature with regard to clinically relevant outcome differences between clean and sterile technique for artificial airway suctioning. However, it is potentially unethical to recommend that further research be conducted to address this gap because the potential for harm with a less-than-sterile environment is a distinct possibility. Therefore, based on committee experience, it is recommended that the clinician use a sterile procedure, when possible, for open suctioning events to protect the patient from potential cross-contamination (evidence level C, all the committee members rated the appropriateness score at 7). At a minimum, in addition to performing hand hygiene on entering and leaving a patient’s room or area, the clinician should perform hand hygiene immediately before performing open suctioning to minimize the risk of introducing any new pathogens into the artificial airway.

Suction Catheter Size and Applied Vacuum Pressure

Research that evaluated the safety and effectiveness of various catheter sizes and applied vacuum pressures is scarce. In a within-subjects repeated-measures study, Javadi et al⁷⁸ evaluated the impact of different sizes of suction catheters on various outcomes such as heart rate, blood pressure, , secretion amount, and pain in adult subjects. In their study, all the subjects were intubated with a size 7.5 inner diameter ETT and were suctioned with both 12 French and 14 French suction catheters randomly assigned according to study protocol. All the subjects were suctioned with both catheter sizes. They reported a significant increase in heart rate, systolic blood pressure, pain, and secretion amount with the use of the larger catheter.

Yousefi et al⁷⁹ conducted a randomized trial that evaluated the impact of 2 levels of applied vacuum pressure (–100 and –200 mm Hg) on physiologic indices in adult subjects. They noted that and heart rate was significantly different before, during, and 5 min and 20 min after suctioning, but there was no difference between the 2 groups. In a prospective study by Singh et al,⁸⁰ the effect of suction catheter outer diameter size in reference to the ETT inner diameter size (small, 0.4; medium, 0.7; and large, 0.9) and vacuum pressures (80, 100, and 120 mm Hg) on various physiologic indices were assessed in pediatric subjects. They found that all suction catheter sizes at varying pressures similarly influenced the physiologic indices.

Based on the available evidence, it seems that various suction catheter sizes and vacuum pressures can cause physiologic alterations. That said, the optimal suction catheter outer diameter size to artificial airway inner diameter size ratio is not known at this time. The optimal applied vacuum pressure that is both safe and effective at clearing secretions is also not known. The 2010 AARC CPG¹ recommended that suction catheters should occlude < 50% of the ETT lumen in pediatric and adult patients, and < 70% in neonates. No new evidence convincingly refutes this recommendation (evidence level C, all the committee members rated the appropriateness score at 7).

There was no formal recommendation on applied vacuum pressure in the previous guideline due to the overall lack of data to support a recommendation.¹ There is minimal evidence that suction pressures should be kept below –200 mm Hg in adults and between –80 and –100 mm Hg in neonates (evidence level C, all the committee members rated the appropriateness score at 7). Efforts to set the suction pressure as low as possible to effectively clear secretions should be made (evidence level C, all committee members rated the appropriateness score at 9).

Duration of the Artificial Airway Suctioning Procedure

Limiting the duration of each session is an intuitive strategy to mitigate the potential complications and/or hazards of artificial airway suctioning. This limitation could apply to either the amount of time the suction catheter is introduced into the artificial airway or the amount of time that suction is applied. Unfortunately, this review of the literature did not find studies that compared patient outcomes with varying lengths of time the catheter is introduced into the airway and/or suction is applied. Most sources, predominantly previous CPG,¹ editorials,^76,81 and textbook chapters,⁸² recommend limiting the duration of the procedure to ≤15 s. The committee’s experience is commensurate with these sources, and the committee recommends keeping each suctioning event as brief as possible and no longer than 15 s (evidence level C, all the committee members rated the appropriateness score at 7).

Shallow Versus Deep Artificial Airway Suctioning Procedure

Research that evaluated the safety and effectiveness of shallow versus deep artificial airway suctioning techniques is limited. Two methodologically similar articles^83,84 were published that compared the effects of shallow and deep ETT suctioning on physiologic indices. Abbasinia et al⁸³ evaluated the 2 techniques on changes to breathing frequency and . In this randomized trial, both the shallow suctioning and deep suctioning groups were preoxygenated and suctioned at the same vacuum pressure (–120 mm Hg) a maximum of 3 times, each for 15 s.⁸³ The diameter of the suction catheter in both groups was half the inner diameter of the ETT; the suction catheter was inserted no further than the end of the ETT in the shallow suction group.⁸³ In the deep suction group, the catheter was passed through the ETT until resistance was met, then pulled back 1 cm before suctioning was performed.⁸³ They noted that breathing frequency and changes were similar between the groups.⁸³ The subjects in the deep suction group required suctioning less frequently.⁸³ Irajpour et al⁸⁴ reported the effects of shallow and deep suctioning techniques on heart rate, systolic blood pressure, diastolic blood pressure, and mean arterial pressure. The changes were similar; however, the investigators did report a slight increase in heart rate and blood pressure measures with deep suctioning.⁸⁴ They noted that increases in each, even to a small degree, could have adverse effects on some patients and that monitoring is necessary during suctioning, particularly during deep suctioning.⁸⁴

In a parallel randomized controlled trial, Shamali et al⁸⁵ compared what they called routine ETT suctioning with a minimally invasive ETT suctioning technique. The routine ETT suctioning technique consisted of manual hyperinflation and preoxygenation for 1 min, and instillation of 8 mL of sterile saline solution.⁸⁵ The suction catheter was advanced down the ETT until resistance was met and withdrawn 1 cm; suctioning was then performed by using a vacuum pressure of –100 to –200 mm Hg for a maximum of 10 s.⁸⁵ The minimally invasive ETT suctioning technique consisted of preoxygenation by the mechanical ventilator for 1 min. The suction catheter was advanced to the distal end of the ETT; suctioning was then performed by using a vacuum pressure of –80 to –120 mm Hg for a maximum of 10 s.⁸⁵ The study investigators noted that the minimally invasive ETT suctioning group had statistically fewer alterations in systolic blood pressure, diastolic blood pressure, mean arterial pressure, and but not in heart rate.⁸⁵ Although it seems that a less-invasive method of suctioning may be warranted to reduce alterations in some physiologic measures due to less physical stimulation, it is unclear which component(s) of routine ETT suctioning (normal saline solution, manual hyperinflation, deep suctioning) impacted these results. In an experimental within-subject designed study that evaluated shallow and deep suctioning techniques on infants at high risk, Ahn and Hwang⁸⁶ noted that deep suctioning did not guarantee the removal of lower airway secretions in neonatal subjects. In fact, they reported that it caused more-direct airway trauma, as evidenced by epithelial damage noted in respiratory aspirates.⁸⁶

Based on the available evidence, it seems that both shallow and deep suctioning techniques cause similar alterations in physiologic indices. Although deep suctioning may result in less-frequent suctioning events, it may be associated with airway trauma. The 2010 AARC CPG¹ recommended the shallow suction technique, citing no definitive benefit of deep suctioning. Since that guideline, no new evidence convincingly impacts this recommendation. It seems that the shallow suctioning technique should be used routinely to avoid potential airway trauma (evidence level B, median appropriateness score 7.7, range 7 - 8). Deep suctioning should generally be used only when shallow suctioning is ineffective with consideration of the potential for airway trauma and the negative impact on physiologic indices (evidence level B, median appropriateness score 7.2, range 7–8).

Bronchoscopy Versus Artificial Airway Suctioning

Bronchoscopy has historically been used for diagnostic purposes or to obtain secretions from specific areas of the lung but not for routine use to clear secretions. A review of the literature yielded 1 study related to routine bronchoscopy use.⁸⁷ Qiao et al⁸⁷ conducted a trial in which 73 adult subjects with a COPD exacerbation were randomized to either routine artificial airway suctioning by using bronchoscopy in conjunction with conventional artificial airway suctioning or conventional artificial airway suctioning alone. The investigators found that there were significantly better outcomes in terms of appearance of the pulmonary infection control window, days of invasive mechanical ventilation, total days of mechanical ventilation, hospital LOS, weaning success, incidence of VAP, and mortality with routine bronchoscopy use in conjunction with conventional artificial airway suctioning. The 2010 AARC CPG¹ did not address bronchoscopy use for routine secretion removal because only 1 study⁸⁷ relevant to this topic has been published to date and that study had limited scope, this committee felt that the routine use of bronchoscopy for secretion removal cannot be recommended (evidence level C, all the committee members rated the appropriateness score at 9).

Artificial Airway (Tube) Scraping Devices

Various devices have been developed for the purpose of clearing ETTs of secretions and biofilm that might increase R_aw and peak inspiratory pressure, and ultimately result in complete airway obstruction. These devices are used in addition to standard suction catheters to maintain the inner diameter of ETTs. A review of the literature resulted in 4 studies^88-91 that assessed changes in R_aw when these devices were used in adult subjects. In separate studies of subjects who required mechanical ventilation, Conti et al⁸⁸ and Scott et al⁸⁹ noted significant reductions in R_aw after the use of experimental obstruction removal devices. In a laboratory study, Adi et al⁹⁰ found that a device designed to clear ETTs of secretions was able to restore inspiratory R_aw of ETTs removed from subjects to levels comparable with that of unused ETTs. In another ex vivo study, by Waters et al,⁹¹ an ETT cleaning device was effective at reducing luminal biofilm secretions and improving pressure drop (an indicator of R_aw) in size 7.5 mm and 8.0 mm ETTs. Of note, the device was not effective at clearing secretions to the level of unused ETTs. Two randomized controlled trials^92,93 found these devices to be effective at reducing mucus accumulation, overall ETT occlusion, maximal ETT occlusion, and biofilm thickness when compared with standard blind suctioning alone. However, these studies did not show improvement in outcomes such as mechanical ventilation days, days in ICU, or days of intubation.^92,93 Evidence supports the use of devices used to clear ETTs when an increase in R_aw and peak inspiratory pressure due to secretion accumulation is suspected (evidence level B, median appropriateness score 8.5, range 8–9). It is not known if these devices should be used intermittently or as part of routine airway management.