Deep versus shallow suction of endotracheal tubes in ventilated neonates and young infants

Spence K, Gillies D, Waterworth L

Background - Methods - Results

Cover sheet

Title

Deep versus shallow suction of endotracheal tubes in ventilated neonates and young infants

Reviewers

Spence K, Gillies D, Waterworth L

Dates

Date edited: 28/05/2003
Date of last substantive update: 04/03/2003
Date of last minor update: / /
Date next stage expected 28/08/2004
Protocol first published: Issue 3, 2002
Review first published: Issue 3, 2003

Contact reviewer

A/Prof Kaye Spence
Clinical Nurse Consultant
Department of Neonatology
The Children's Hospital at Westmead
Locked Bag 4001
Westmead
NSW AUSTRALIA
2145
Telephone 1: 61 2 98452720
Facsimile: 61 2 98452251
E-mail: Kaye@chw.edu.au

Contribution of reviewers

Kaye Spence undertook search, wrote review
Donna Gillies undertook search, assisted in writing review
Lynne Waterworth instigated review, reviewed review

Internal sources of support

Department of Neonatology, The Children's Hospital at Westmead, AUSTRALIA
Centre for Research and Evidenced-based Nursing, The Children's Hospital at Westmead, AUSTRALIA
NETS, Western Sydney Area Health Service, AUSTRALIA

External sources of support

Neonatal Review Group Support Project funded by Department of Health and Aging, Australian Government, AUSTRALIA

What's new

Dates

Date review re-formatted: / /
Date new studies sought but none found: / /
Date new studies found but not yet included/excluded: / /
Date new studies found and included/excluded: / /
Date reviewers' conclusions section amended: / /
Date comment/criticism added: / /
Date response to comment/criticisms added: / /

Text of review

Synopsis

No evidence from trials about the optimum depth for catheter insertion when suctioning clear the endotracheal tube in babies in neonatal intensive care

Babies in neonatal intensive care often need mechanical ventilation to assist breathing. This involves inserting an endotracheal tube (ETT) down the baby's windpipe so that a machine ventilator can help the baby breathe. Lung secretions can build up in the tube and cause blockages. Buildup is minimized by suctioning the ETT clear with a catheter (small tube). One of the variations of technique possible for suctioning is depth of catheter insertion into the ETT. However, the review found no trials to show what depth of insertion of catheter into the endotracheal tube gains optimal clearance without damaging the baby's lungs.

Abstract

Background

Mechanical ventilation is commonly used in Neonatal Intensive Care Units to assist breathing in a variety of conditions. Mechanical ventilation is achieved through the placement of an endotracheal tube (ETT) which is left in-situ. The ETT is suctioned to prevent a build-up of secretions and therefore blockage of the airway. Methods of suctioning the endotracheal tube vary according to institutional practice and the individual clinician performing the task. The depth of suctioning is one of these variables. The catheter may be passed to the tip of the ETT or beyond the tip into the trachea or bronchi to facilitate removal of secretions. However, trauma to the lower airways may result from the suction catheter being passed into the airway beyond the tip of the endotracheal tube.

Objectives

To compare the effectiveness and complications of deep (catheter passed beyond the tip of the ETT) versus shallow (catheter passed to length of ETT only) suctioning of the endotracheal tube in ventilated infants.

Search strategy

Using text words and subject headings relevant to endotracheal suctioning, searches were made of the Oxford Database of Perinatal Trials, Cochrane Register of Controlled Trials (The Cochrane Library, Issue 3, 2002), MEDLINE (from January 1966 to December 2002, all languages), CINAHL (from 1982 to 2002). In addition, a call was placed on the list servers, NICU-NET and Neonatal-Talk for unpublished trials, conference presentations and current trials.

Selection criteria

Controlled trials using random or quasi-random allocation of neonates receiving ventilatory support via an endotracheal tube to either deep or shallow endotracheal suctioning.

Data collection & analysis

No studies were found meeting the criteria for inclusion in this review

Main results

No studies were found meeting the criteria for inclusion in this review

Reviewers' conclusions

There is no evidence from randomised controlled trials concerning the benefits or risks of deep versus shallow suctioning of endo-tracheal tubes in ventilated neonates and infants. Further high quality research would be required to conclusively establish whether there are any benefits to deep or shallow suctioning. However, as it may be considered unethical to conduct a trial of deep suctioning given anecdotal evidence regarding possible damage to the airway, it is proposed that a randomised controlled trial comparing deep with shallow suctioning may be considered in a NICU where the standard practice includes a deep suctioning technique.

Background

Mechanical ventilation is commonly used to assist breathing in a variety of conditions in the Neonatal Intensive Care Unit. Mechanical ventilation is achieved through the placement of an endotracheal tube that is left in-situ. There are a number of potential problems associated with this intervention. Tube blockage, discomfort, hypoxemia, hypercapnoea and lobar collapse are all possible complications associated with endotracheal tubes.

The presence of the endotracheal tube causes soft tissue irritation and increased secretions due to suppression of normal ciliary action. In addition, the infant is unable to cough (Sturges 1979), which reduces the ability to clear secretions. The aim of endotracheal suctioning is to reduce the problems resulting from a build-up of secretions and, therefore, possible tube obstruction. Documented complications associated with endotracheal suctioning include hypoxaemia, bradycardia, tachycardia, atelectasis, pneumonia, fluctuations in blood pressure and intracranial pressure, localised trauma to the airway, sepsis, tube blockage, and tube dislodgement (Boothroyd 1996; Simbruner 1981; Gunderson 1986; Brodsky 1987; Durand 1989; Shorten 1991).

Protocols for maintaining patency of the endotracheal tube vary widely among institutions and are not, in general, based on sound evidence (Tolles 1990; Copnell 1995). Potentially harmful suctioning techniques such as frequent and deep suctioning, head turning, and multiple catheter passes have been questioned (Wrightson 1999). However, much of the practice of suctioning endotracheal tubes appears to be based on ritual rather than a physiological rationale or reliable evidence. Endotracheal tube suctioning remains a routine practice in the neonatal intensive care unit (Cameron 2000) with different practices across NICU's. Therefore, it is important that methods of suctioning the endotracheal tube that minimise complications are identified and implemented into practice.

Concern about the inadequate removal of secretions and subsequent tube blockage has increased the practice of deep suctioning. Although Darlow 1997 in a comparative study found that the removal of secretions using a dry shallow technique was adequate for obtaining samples of mucous for research, some research had shown that deep suction into the bronchial tree increases the mucous obtained on suction (Bailey 1988). Trauma to the lower airways may result from deep suctioning due to the suction catheter being passed into the airway beyond the tip of the endotracheal tube (Miller 1981; Brodsky 1987; Bailey 1988) and from repeated insult from suction catheters (Grylack 1984). Diligent attention to the length of the suction catheter in relation to the endotracheal tube may prevent this trauma. It has been speculated that bradycardia during endotracheal suctioning results from a vagal reflex initiated by stimulation of the airway mucosa that occurs when the catheter is passed beyond the tip of the endotracheal tube. Therefore, some authors have recommended the catheter be passed no farther than the tip of the ETT (Bailey 1988; Runton 1992; Harling 2000) and have provided guidelines for the length of the catheter to be inserted based on the size of the tube.

Objectives

To compare the effectiveness and complications of deep (catheter passed beyond the tip of the ETT) versus shallow (catheter passed length of ETT only) suctioning of the endotracheal tube in ventilated infants.

Subgroup analyses are planned on the basis of endotracheal tube size (with five subgroups ranging from 2mm to 4mm) and the duration of tube placement (with two subgroups, less than or equal to 48 hours or greater than 48 hours).

Criteria for considering studies for this review

Types of studies

Controlled trials using random or quasi-random allocation of patients to either deep or shallow endotracheal suctioning

Types of participants

Neonates receiving ventilatory support via an endotracheal tube.

Types of interventions

Types of outcome measures

Primary
1. Tube removal (for suspected or actual blockage of the endotracheal tube)
2. Volume and consistency of secretions removed during suctioning procedure (mucous plugs, tenacious, minimal, copious, thin)
3. Tracheal or bronchial damage (ulceration, inflammation and/or ciliary damage)

Secondary
4. Level of oxygenation, absolute or percentage change after suctioning (measured by transcutaneous oxygenation, saturation or arterial blood gas).
5. Heart rate, absolute or percentage change after suctioning (measured on a cardio-respiratory monitor)
6. Atelectasis (lung collapse on chest x-ray)
7. Air leak (pneumothorax on chest x-ray)

Search strategy for identification of studies

The combined databases of the Neonatal Review Group were searched using terms relevant to endotracheal suctioning. This included searches of the Oxford Database of Perinatal Trials, Cochrane Register of Controlled Trials (The Cochrane Library, Issue 3, 2002), MEDLINE (from January 1966 to December 2002, all languages), CINAHL (from 1982 to 2002). The search terms used included MeSH headings, subjects, textwords, wild cards and/or keywords relevant to the following terms: newborn, neonate, infant, ventilation, mechanical ventilation, intubated, intubation, endotracheal, tracheal, endotracheal tube, endotracheal suction, tracheal suction, tracheal injury, bronchial injury, catheters, secretions, techniques. A call was placed on the list servers, NICU-NET and Neonatal-Talk for unpublished trials, conference presentations and current trials.

Methods of the review

The systematic review followed the method described in the Cochrane Collaboration Handbook. The three reviewers worked independently to search for and assess trials for inclusion and methodological quality. Studies were to be assessed for four major sources of potential bias and methods of avoidance as follows: 1. Selection bias - blinding of randomisation 2. Performance bias - blinding of intervention 3. Attrition bias - complete follow-up 4. Detection bias - blinding of outcome assessment. In the case of cross-over trials data from both periods were to be used for analysis if possible. The reviewers were to judge from the report of the trial whether each of the criteria for method of avoidance of bias was met. Each criterion was to be given a rating of either A (Adequate), B (Unclear), or C (Inadequate).

To measure the effect of the different methods of suctioning the relative risk (RR), risk difference (RD), number needed to treat (NNT), or number needed to harm (NNH) and 95% confidence intervals (CI) were to be calculated for bivariate outcomes. The weighted mean difference (WMD) and its 95% CI was to be calculated for continuous outcomes. The fixed effect model was to be used in the meta-analysis if there was no heterogeneity among studies. Subgroup analyses were to be performed as proposed if data permitted.

Description of studies

No eligible studies comparing deep with shallow suction were found that met the criteria for inclusion in this review.

Methodological quality of included studies

No studies were found that met the criteria for inclusion in this review

Results

No studies were found that met the criteria for inclusion in this review

Discussion

As there were no relevant RCTs found, this systematic review has failed to determine whether deep or shallow suctioning of the endo-tracheal tube is more effective or causes less harm for ventilated neonates and infants. Based on the evidence discussed in the Background, deep suctioning is potentially harmful to the trachea and bronchi in ventilated neonates. However, it must be kept in mind that there are methodological deficiencies in these studies that limit the validity of the findings.

Research describing the potential negative effects of deep suctioning has been reported dating back to the 1960s (Thambiran 1966). Insertion of suction catheters to the end of the endo-tracheal tube has been recommended based on findings from electron microscopy in young rabbits where there was an increase in the area of tracheal necrosis and inflammation when deep suctioning was performed (Bailey 1988). A study comparing uncontrolled deep suctioning to controlled shallow suctioning in low birth weight infants suggested there was more severe tracheal pathology at autopsy in the infants who received deep suctioning (Brodsky 1987). However, these findings were not statistically significant, and this study used historical controls with several confounding factors. In a series of case reports where granulation tissue in the bronchi of premature infants was identified, the authors postulated that these findings were a response to repeated mechanical trauma of endo-tracheal tube suctioning (Miller 1981). The recommendations resulting from all of these findings were for modifications to the suction procedure to avoid the catheter tip extending beyond the tip of the endo-tracheal tube (Bailey 1988; Brodsky 1987; Miller 1981). Despite these recommendations from the 1980s the practice of deep suctioning continues in some NICU's (Tolles 1990; Copnell 1995). This may be a deliberate practice due to the belief that deep suctioning works better at removing secretions and helps maintain tube patency. However, we could not find any evidence from randomised trials to support or refute this practice.

The practice of suctioning the endo-tracheal tube of ventilated neonates and infants continues without adequate evidence on the various techniques used. There have been many protocols and guidelines published to assist caregivers in determining the most appropriate method for suctioning endo-tracheal tubes in neonates (Hodge 1991; Runton 1992; Knox, 1993; Young 1995; Wrightson 1999; Pollard 2001). However, surveys from practice indicate that protocols vary widely and are not, in general, based on sound evidence (Tolles 1990; Copnell 1995).

Reviewers' conclusions

Implications for practice

There is no evidence from randomised controlled trials to refute or support the practice of deep or shallow suctioning of endo-tracheal tubes in ventilated neonates and infants. However, given the evidence from uncontrolled and observational studies which have compared the techniques, there appears to be a realistic concern regarding the practice of deep suctioning.

Implications for research

There is no evidence from randomised controlled trials concerning the benefits or risks of deep versus shallow suctioning of endo-tracheal tubes in ventilated neonates and infants. Further high quality research is required to conclusively establish whether there are any benefits to deep versus shallow suctioning. Given the reviewers' concern that a randomised controlled trial comparing deep with shallow suctioning may be considered unethical based on the available anecdotal evidence that deep suctioning results in trauma to the trachea, we would suggest a RCT may be possible in a NICU where the standard suctioning practice includes a deep suctioning technique.

Acknowledgements

Potential conflict of interest

None

Other references

Additional references

Bailey 1988

Bailey C, Kattwinkel J, Teja K, Buckley T. Shallow versus deep endotracheal suctioning in young rabbits: pathologic effects on the tracheobronchial wall. Pediatrics 1988;82:746-751.

Boothroyd 1996

Boothroyd AE, Murthey BV, Darbyshire A, Petros AJ. Endotracheal suctioning causes right upper lobe collapse in intubated children. Acta Paediatr 1996;85:1422-1425.

Brodsky 1987

Brodsky L, Reidy M, Stanievich JF. The effects of suctioning techniques on the distal mucosa in intubated low birth weight infants. Int J Pediatr Otorhinolaryngol 1987;14:1-4.

Cameron 2000

Cameron J, Haines J. Management of Respiratory Disorders. In: Boxwell G, editor(s). Neonatal Intensive Care Nursing. London: Routledge, 2000:96-124.

Copnell 1995

Copnell B, Fergusson D. Endotracheal suctioning: time-worn ritual or timely intervention? Am J Crit Care 1995;4:100-105.

Darlow 1997

Darlow BA, Sluis KB, Inder TE, Winterbourn CC. Endotracheal suctioning of the neonate: comparison of two methods as a source of mucous material for research. Pediatr Pulmonol 1997;23:217-221.

Durand 1989

Durand M, Sangha B, Cabal LA, Hoppenbrouwers T, Hodgman JE. Cardiopulmonary and intracranial pressure changes related to endotracheal suctioning in preterm infants. Crit Care Med 1989;17:506-510.

Grylack 1984

Grylack LJ, Anderson KD. Diagnosis and treatment of traumatic granuloma in tracheobronchial tree of newborn with history of chronic intubation. J Pediatr Surg 1984;19:200-201.

Gunderson 1986

Gunderson LP, McPhee AJ, Donovan EF. Partially ventilated endotracheal suction. Use in newborns with respiratory distress syndrome. Am J Dis Child 1986;140:462-465.

Harling 2000

Harling E. Diagnostic and Therapeutic Procedures. In: Boxwell G, editor(s). Neonatal Intensive Care Nursing. London: Routledge, 2000:285-314.

Hodge 1991

Hodge D. Endotracheal suctioning and the infant: a nursing care protocol to decrease complications. Neonatal Netw 1991;9:7-13.

Knox, 1993

Knox, AM. Performing endotracheal suction on children: a literature review and implications for nursing practice. Intensive Crit Care Nurs 1993;9:48-54.

Miller 1981

Miller KE, Edwards DK, Hilton S, Collins D, Lynch F, Williams R. Acquired lobar emphysema in premature infants with bronchopulmonary dysplasia: An iatrogenic disease? Radiology 1981;138:589-592.

Pollard 2001

Pollard C. Endotracheal suction in the infant with an artificial airway. Nurs Crit Care 2001;6:76-82.

Runton 1992

Runton N. Suctioning artificial airways in children: appropriate technique. Pediatr Nurs 1992;18:115-118.

Shorten 1991

Shorten DR, Byrne PJ, Jones RL. Infant responses to saline instillations and endotracheal suctioning. JOGNN 1991;20:464-469.

Simbruner 1981

Simbruner G, Coradello H, Foder M, Havelec L, Lubec G, Pollak A. Effect of tracheal suction on oxygenation, circulation, and lung mechanics in newborn infants. Arch Dis Child 1981;56:326-330.

Sturges 1979

Sturges JM. Mucous secretions in the respiratory tract. Pediatr Clin North Am 1979;26:481-501.

Thambiran 1966

Thambrian AK, Ripley SH. Observations on tracheal suction: an experimental study. Br J Anaesth 1966;38:459.

Tolles 1990

Tolles CL, Stone K. National survey of neonatal endotracheal suctioning procedures. Neonatal Netw 1990;9:7-14.

Wrightson 1999

Wrightson DD. Suctioning smarter: answers to eight common questions about endotracheal suctioning in neonates. Neonatal Netw 1999;18:51-55.

Young 1995

Young J. To help or hinder: endotracheal suction and the intubated neonate. J Neonat Nurs 1995;1:23-28.

Notes

Published notes

Amended sections

Cover sheet
Synopsis
Abstract
Background
Objectives
Criteria for considering studies for this review
Search strategy for identification of studies
Methods of the review
Description of studies
Methodological quality of included studies
Results
Discussion
Reviewers' conclusions
Other references

Contact details for co-reviewers

Dr Donna Gillies
Senior Research Fellow
Centre for Research and Evidenced-based Nursing
The Children's Hospital at Westmead
Locked Bag 4001
Westmead
NSW AUSTRALIA
2145
Telephone 1: +61-2-98453610

Ms Lynne Waterworth, RN
Registered Nurse
NSW Newborn and Pregnancy Emergency Transport Service
Western Sydney Area Health Service
AUSTRALIA

This review is published as a Cochrane review in The Cochrane Library 2003, Issue 3, 2003 (see www.CochraneLibrary.net for information).  Cochrane reviews are regularly updated as new evidence emerges and in response to comments and criticisms, and The Cochrane Library should be consulted for the most recent version of the Review.