Endotracheal intubation is a common procedure in the NICU and accurate positioning of the endotracheal tube (ETT) is essential to prevent associated morbidity. This is applied more so in cases of extremely premature babies where the trachea is much shorter, leaving little margin for error. Given that the difference between extubations and bronchial intubation can be less than a couple of centimeters, it is not surprising that the staff performing an emergency intubation are likely to insert the ETT deeper than required in order to avoid the risk of inadvertent extubations, especially during ETT taping; however this does give rise to an increased risk of right main stem intubation.
Many formulae have been proposed in an attempt to accurately estimate the depth of insertion of the ETT in order to place it at the mid-tracheal position. These are not always accurate, in particular at the extremes of low gestational age (ELGA) or in SGA infants when using body weight derived formulae. Compounding factors such as activity level, securing mechanisms, and route of intubation may impact the likelihood of malposition.
One study suggested gestational age based guidelines for ETT depth estimation and confirmed a significant reduction in the need for repositioning and incidence of uneven lung expansion [
We conducted this survey to examine the beliefs and current practices across Canada in regard to endotracheal tube placement and to understand the challenges faced by current practices. We hypothesized that there would be wide variability in practices in how to determine ETT placements across Canada. The majority would be using the weight based guidelines for ETT depth estimation and finding the estimation of depth of insertion challenging especially in infants with a birth weight <750 g. Medical practitioners are likely to insert ETT deeper than T2 to avoid the risk of extubations. Most respondents would also prefer frequent measurement markings on the ETT as a guide to correct placement. The results of the survey developed should act as a needs assessment and serve as the basis for future work in addressing issues related to ETT placement in neonates especially in the ELGA infant.
A cross-sectional survey of a sample of health care professionals involved in neonatal intubations across Canada was performed. Research Ethics Board approval was obtained from the Hospital for Sick Children. Clinical directors in the Canadian Neonatal Network affiliated NICUs and Neonatal-Perinatal Program Directors were invited to participate in and disseminate the survey invitation to their staff including neonatologists, neonatal fellows, registered respiratory therapists (RRTs), and nurse practitioners (NPs). Consent was implied by participation. Email reminders were sent at three and five weeks after initial email invitation.
The questionnaire was web based with 35 close ended questions requiring approximately 15 minutes to answer. It was devised using a modified Delphi process with input from a variety of health care professionals representing the participating disciplines. A pilot survey was administered to representatives of these stakeholder groups and modifications to the questionnaire were made based on this feedback. The questions are placed under 6 headings: personal experience, unit experience, challenges in depth estimation, positioning of ETT, challenges in positioning, and complications of malposition as shown in the Appendix. The results were analyzed using simple descriptive statistics.
The clinical directors were identified from Canadian Neonatal Network affiliated NICUs and Neonatal-Perinatal Programs across Canada. They were invited via email to participate in and disseminate the survey. A total of 207 responses were received of which 85.5% were completed.
The representation of the various professions within the respondents is outlined in Table
Representation of respondent.
Response | Percentage |
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Respiratory therapist | 47.2% |
Staff neonatologist | 18.0% |
Neonatology fellow | 21.3% |
Nurse practitioner | 13.5% |
The majority of respondents (87%) used “weight +6” formula and “aim to black line” to estimate the depth of insertion of an oral ETT. Most respondents reported that they found the estimation of depth of insertion challenging in ELBW infants. Very few (22%) believed that the gestation age based guidelines may give better estimation of the depth of ETT insertion. Although the respondents (92%) identified mid-trachea as the ideal ETT tip position (Table
Ideal position of the ETT.
Response | Percentage |
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Upper trachea | 3.9% |
Mid-trachea | 91.1% |
Lower trachea | 5.0% |
Ideal position on X-ray.
Response | Percentage |
---|---|
C7-T1 | 4.5% |
T1-T2 | 34.7% |
T2-T3 | 51.7% |
T3-T4 | 5.1% |
Unsure | 4% |
Preferred practices.
Oral intubation | Unit (45%) transport (59%) |
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Premedication for elective/planned intubation | Always or almost always (combined 93%) |
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Methods to secure ETTs | (i) Tapes only (40%) |
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Other methods used for securing ETT | NeoBar, tapes with NeoBar, and NeoBridge |
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Point of measurement for an oral ETT | Upper lip (70%) |
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Confirming the ETT position | (i) 69% use 1 view (AP view) |
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Reintubations (length same as before) | 94% would not get an X-ray |
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Position of the head during the CXR | Neutral or midline (62%) |
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Analgesia/sedation during mechanical ventilation | Sometimes (66%) |
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Accidental extubations were reported | Occasionally by 76% |
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Knowledge about the level of the vocal cords and carina | Marked differences |
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Effects of flexion and extension on the ETT position | Marked differences |
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Auscultation of the bilateral breath sounds was not believed to rule out endobronchial intubations | 70% agreed |
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Tube repositioning | (i) 81% felt the need to reposition the ETT sometimes |
Respondents felt that the most commonly seen complications of malpositioning were atelectasis (82%), differential air expansion (68%), unequal surfactant administration (61%), pneumothorax (29%), and PIE (14%).
Half of the respondents felt that more precise markings on the ETT would assist in better positioning of the ETT tip, although another 27% were unsure of the value. Most preferred markings every 5 mm.
We found significant variability in the ETT placement practices across Canada. A few of the practices utilized could be further enhanced by having markings on ETT every 5 mm.
Endotracheal intubation is often performed in an emergent situation utilizing the weight based guide (weight +6) to estimate the insertion length of the ETT in order to be positioned mid trachea. Weight is often not available at the time of intubation at birth and a rough estimate is used to determine the insertion length. This is supplemented with the aim to position the black line of the ETT at the level of the vocal cords and produce bilateral equal air entry to guide its optimal placement. This has also been the recommendations of the American Academy of Pediatrics Neonatal Resuscitation Program without addressing the babies with birth weight less than 1000 gms [
Accurate positioning of the endotracheal tube (ETT) is essential to prevent associated morbidities, more so in cases of extreme premature babies where the trachea is much shorter, which leaves the clinicians with little margin for error. Therefore, satisfactory positioning of the tip of ET tube on initial intubation is extremely important. Weight is not a good predictor of the upper airway distances as shown in a postmortem study on 24 infants ranging from 23-week gestation to term plus 8 weeks [
Within the neonatal literature, there is limited data regarding the ideal placement of the ETT tip within the trachea. Many have defined this level as the 1st or 2nd thoracic vertebrae [
The newborn larynx is positioned higher in the neck, it extends from C3 to C5 and carina is situated between T3 and T5 and most commonly at T4 [
Tracheal position is affected by both respiratory movements and changes in head position such that flexion of neck and expiration shortens the distance pushing the ETT tip towards the carina and extension of the neck and inspiration retracts the ETT tip away from the carina [
As the difference between extubations and bronchial intubation is only a matter of a couple of centimeters, more so in smaller babies, it is not surprising that the resident staff performing an emergency intubation are likely to insert the ETT deeper than required into the airway to avoid the risk of extubations with enhanced risk of right main stem intubation and/or atelectasis of right upper lobe of lung not to mention unilateral surfactant administration.
There has been no evidence to date that keeping the ETT tip between T1 and T2 is associated with the increase incidence of the unplanned extubations. On the contrary, T1-T2 has been reported as an ideal position for ETT tip [
The rule of 7-8-9 (weight +6) is universally followed to estimate the depth of an oral ETT to accurately place it at the mid-tracheal level. This rule was suggested by Tochen in 1979 who studied 40 neonates ranging from 26 to 44 weeks with the weight of 700–4100 grams and reference to T1-T2 as a mid-tracheal position. There were only ten babies under 1000 gms and none below 750 gms. They showed a linear relationship between tube length and weight with a correlation coefficient of 0.96 and assumed this even in babies <1000 gms [
These gestational age based guidelines [
Most of the respondents also acknowledged that more precise marking on the ETT may help in better positioning of the ETT tube and prefer at least 5 mm markings. We strongly support this idea and feel this should be considered by the manufacturing companies.
There are several limitations of this survey. The clinical directors and the Neonatal-Perinatal Program directors were approached to participate in and disseminate the survey to the specified groups working in their institute. We are unable to report the response rate as the exact number to whom the survey was sent out could not be ascertained and so the results may not represent all of the practices across Canada. However beliefs can form the basis of actions and the survey does highlight the issues related to challenges encountered in the ETT placement especially in the very preterm infant.
In conclusion, we noticed a wide variability in the beliefs related to ideal ETT placement across Canada. Our survey suggests that there is a real need for more research and consensus statement on the ideal position of the ETT with recognition that even a minor length difference may make a huge impact on the respiratory morbidity. Precise attention to ETT securing methods and need for regular review including chest X-ray should also be considered part of regular monitoring to ensure correct positioning once placement is verified. Industry should consider more frequent markings on the ETT to aid in better placement.
What is your occupation?
◯ Respiratory Therapist ◯ Staff Neonatologist ◯ Neonatology Fellow ◯ Nurse Practitioner
How many years of NICU experience do you have?
◯ <5 ◯ 5–9 years ◯ 10–14 years ◯ >15 years
On average how many intubations do you perform per year?
◯ <5 ◯ 5–14 ◯ 15–25 ◯ >25
What is the Level of your NICU?
□ Level 1 □ Level 2 □ level 2 (advanced) □ Level 3
Type of NICU?
□ Inborn □ Outborn □ Both
Who routinely performs intubations in the unit? (tick all that apply)
□ Resident □ Fellows □ Staff (consultant) □ Respiratory therapist □ Nurse Practitioners □ Other (specify) ______________________
What types of intubation are performed in your unit?
□ Predominantly oral □ Predominantly nasal □ Both
What type of intubations do you perform for neonatal transport?
□ Primarily oral □ Primarily nasal
Do you premedicate for elective/planned intubations (e.g., opioid and/or muscle relaxation)?
□ Always □ Almost always □ Sometimes □ Almost never □ Never
How often do you use analgesia and/or sedation during mechanical ventilation?
□ Always □ Almost always □ Sometimes □ Almost never □ Never
How do you secure your ETTs?
□ Tapes only □ Tape plus liquid adhesive (i.e., Mastisol). □ Tapes plus suture through ETT. □ Tapes, liquid adhesive (i.e., Mastisol) plus suture through ETT. □ Other – please specify ______________________
In my unit, unintentional extubations are seen?
□ Often □ Occasionally □ Almost never □ Never
How do you estimate the depth of insertion of an oral ETT? (tick all that apply)
□ Weight +6 cm □ Gestational age estimate □ Other weight estimate □ Aim to black line □ Other (specify) ______________________ □ Not applicable
How do you estimate depth of insertion for a nasal ETT? (tick all that apply)
□ Weight +7 cm □ Gestational age estimate □ Other weight estimate □ Aim to black line □ Other (specify) ______________________ □ Not applicable
I find estimating the depth of ETT insertion challenging in (tick all that apply)
□ Infants □ 750–999 g □ 1–1999 kg □ 2-3 kg □ >3 kg □ None of the above □ Unsure
Do you think narrower gestational age calculations may give better estimation of the depth of ETT tube?
□ Yes □ No □ Unsure
More precise weight adjusted calculations for ETT depth estimation may be useful in (tick all that apply)
□ Infants □ 750–999 g □ 1–1999 g □ 2-3 kg □ >3 kg □ None of above □ Unsure
From what point do you calculate the oral ETT measurement? □ Upper Gum □ Upper Lip □ Others ______________________ □ Not applicable
Which do you think is a better point for measurement of an oral ETT? □ Upper Gum □ Upper Lip □ Others ______________________ □ Not applicable
What in your opinion is the ideal position of the ETT tip in a neonate? □ Upper Trachea □ Mid Trachea □ Lower Trachea
The ideal position of the ETT tip on X-Ray is
□ C7-T1 □ T1-T2 □ T2-T3 □ T3-T4 □ Unsure
The Level of vocal cords in neonates is
□ C3-C4 □ C4-C5 □ C5-C6 □ C6-C7 □ C7-T1 □ Unsure
The level of carina in a neonate is. (Tick all that applies)
□ T3-T4 □ T4-T5 □ T3–T5 (mostly at T4) □ T5-T6 □ T4–T6 (mostly at T5) □ Unsure
Flexion of the neck
□ Pushes the ETT down □ Pulls the ETT up □ Does not impact □ Unsure
Extension of the neck
□ Pushes the ETT down □ Pulls the ETT up □ Does not impact □ Unsure
How do you confirm ETT position? (Tick all that applies)
□ Chest X-ray – 2 views (AP & Lateral) □ Chest X-ray – 1 view (AP only) □ Chest X-ray 1 view (Lateral only) □ Ultrasound □ Auscultation of breath sounds □ Other (specify) ______________________
How often do you perform a CXR after intubation?
□ Always □ Almost always □ Almost never □ Never
I do not perform a CXR post intubation if (tick all that apply)
□ Air entry sounds equal □ Improvement in clinical status □ Colour change with Co2 detector □ Measurement appropriate by weight +6/7 rule □ Measurement appropriate by gestational age estimates □ Previously intubated and ETT measurement same
Do you have specific head positional requirements for the infant during CXR
□ Yes □ No □ If yes, please specify ______________________
In my opinion auscultation of bilateral equal breath sounds rules out right mainbronchus intubation? □ Yes □ No □ Unsure
How often do you have to reposition your ETT after X-ray? □ Always □ Almost always □ Sometimes □ Almost never □ Never □ Unsure
I would reposition the ETT if on the chest X-Ray it is at (tick all that apply)
□ C7-T1 □ T1-T2 □ T2-T3 □ T3-T4 □ T5 and below
Do you think better positioning of the ETT tip could be achieved with more precise markings on ETT (current markings every 10 mm)
□ Yes □ No □ Unsure
If yes, what markings would you prefer to see?
□ Every 2 mm □ Every 5 mm □ Others, Please specify ______________________ □ Not applicable
Complications of ETT malpositioning I most commonly see are (tick all that apply)
□ Unequal surfactant administration □ Differential Air expansion □ Atelectasis □ Pneumothorax □ PIE □ Others ______________________
No external funding was secured. The authors have no financial relationships relevant to this paper and no conflict of interests to disclose.
The authors want to thank all the staff members of CNN NICUs who completed their survey.