Endotracheal Tube Depth Research Articles

Legal Briefs: Iatrogenesis: Prolapsed Umbilical Cord After Artificial Rupture of the Membranes and Unskilled Stabilization

* Abbreviations: AROM, : artificial rupture of the membrane ETT, : endotracheal tube FP, : family practitioner HR, : heart rate PPHN, : pulmonary hypertension of the newborn PPV, : positive pressure ventilation A 3,530-g term infant was delivered to a 22-year-old G1P0 mother who had an unremarkable prenatal course. She smoked during pregnancy and had a placenta previa that resolved by mid-gestation. A family practitioner (FP) was the treating physician during pregnancy. He decided at 39 1/2 weeks’ gestation to induce because of “uterine irritability.” When asked during the deposition why he induced labor, he said that the mother complained of abdominal discomfort, and she was at high risk because of her smoking. The plaintiff obstetrician was critical of the decision to induce because a valid reason was lacking, in his opinion. The defense obstetrician countered by saying 39 weeks is an acceptable gestation to induce. The plaintiff obstetrician said it was very unlikely that a successful induction would occur because the mother was a prima gravida, the fetus was large, and the cervix was unfavorable. Induction was by dinoprostone, followed by oxytocin (Pitocin®, JHP Pharmaceuticals, LLC, Rochester, MI) augmentation. When the cervix was 70% effaced and 2 cm dilated, and the fetus was at a −2 station, the FP decided to rupture the membranes. A few minutes after artificial rupture of the membranes (AROMs), multiple severe variable decelerations occurred, and 8 minutes after AROMs a prolapsed cord was discovered; the fetal heart rate (HR) became 50 beats per minute. The plaintiff obstetrician was critical of the decision to rupture the membranes because the fetal head was not engaged. The FP defendant said that the head was “well applied” to the cervix. The defense obstetrician said that because the FP said the head was well applied to the cervix, it was within standard of care to perform AROM even if the head was not technically engaged. All agreed that engagement of the head meant that in cephalic presentations …

Tracheal palpation to assess endotracheal tube depth: an exploratory study

Correct placement of the endotracheal tube (ETT) occurs when the distal tip is in mid-trachea. This study compares two techniques used to place the ETT at the correct depth during intubation: tracheal palpation vs placement at a fixed depth at the patient's teeth. With approval of the Research Ethics Board, we recruited American Society of Anesthesiologists physical status I-II patients scheduled for elective surgery with tracheal intubation. Clinicians performing the tracheal intubations were asked to "advance the tube slowly once the tip is through the cords". An investigator palpated the patient's trachea with three fingers spread over the trachea from the larynx to the sternal notch. When the ETT tip was felt in the sternal notch, the ETT was immobilized and its position was determined by fibreoptic bronchoscopy. The position of the ETT tip was compared with our hospital standard, which is a depth at the incisors or gums of 23 cm for men and 21 cm for women. The primary outcome was the incidence of correct placement. Correct placement of the ETT was defined as a tip > 2.5 cm from the carina and > 3.5 cm below the vocal cords. Movement of the ETT tip was readily palpable in 77 of 92 patients studied, and bronchoscopy was performed in 85 patients. Placement by tracheal palpation resulted in more correct placements (71 [77%]; 95% confidence interval [CI] 74 to 81) than hospital standard depth at the incisors or gums (57 [61%]; 95% CI 58 to 66) (P = 0.037). The mean (SD) placement of the ETT tip in palpable subjects was 4.1 (1.7) cm above the carina, 1.9 cm (1.5-2.3 cm) below the ideal mid-tracheal position. Tracheal palpation requires no special equipment, takes only a few seconds to perform, and may improve ETT placement at the correct depth. Further studies are warranted.

Optimal insertion depth of endotracheal tube among Japanese

To the Editor: A recent clinical trial from Austria recommended ‘‘the 20/22 cm rule’’ to determine the insertion depth of an endotracheal tube (ETT) to 20 cm in women and 22 cm in men, measured at the corner of the mouth [1]. In this study, we determined the insertion depth of ETT using the vocal cord marker, measured the distance between the distal tip of ETT and carina (T–C length), and compared the actual distance with the calculated distance if the insertion depth of ETT was determined by the 20/22 cm rule. This retrospective study was approved by the research ethics committee of Kyorin University Hospital, which granted a waiver of written informed consent. In 69 Japanese patients undergoing general anesthesia requiring oral endotracheal intubation, we decided the depth of ETT using the vocal cord marker during tracheal intubation. We measured the T–C length on a portable chest radiograph taken at the end of surgery (the T–C length by the vocal cord marker). In the same patients, we calculated the T–C length if the depth of ETT was determined by the 20/22 cm rule (the T–C length by the 20/22 cm rule). According to the T–C length, the insertion depth of ETT was defined as ‘‘appropriate’’ (2–6 cm), ‘‘shallow’’ ([6 cm), and ‘‘deep’’ (\2 cm). Figure 1 shows the T–C length by the vocal cord marker and by the 20/22 cm rule. No statistical difference in the T–C length was detected by paired t test, although these nonsignificant differences can be false negatives because of the limited sample size. However, three females shorter than 150 cm in height were supposed to get endobronchial intubation when the depth of ETT was determined by the 20/22 cm rule. In conclusion, when we apply the 20/22 cm rule to Japanese patients, caution is needed for females shorter than 150 cm.

Are anatomical landmark measurements accurate for predicting endotracheal tube depth?

Background: A traditional method for depth of intubation in adult patients is taping the endotracheal tube (ETT) at the upper incisors a distance of 21 or 23 cm for women and men respectively (21/23 method). A novel “topographical” measurement for estimating proper intubation depth has been suggested as a better depth predictor compared to the 21/23 method. Objectives: To compare the 21/23 method to topographical measurements. Methods: 100 ASA physical status I-II patients scheduled for elective surgery were enrolled. The 21/23 method was initially utilized for intubation and the ETT tip to carina distance was then fiberoptically measured. Anatomical (topographical) measurements were then obtained from each patient by adding the distance from the corner of the mouth to the mandibular angle to the distance from the mandibular angle to the center of the sternal notch and were recorded as the topographical intubation depth. Both measurements were assessed for percentage of ETTs that fell outside of our desired tip to carina range of 2-4 cm. Results: After the 21/23 method, 29% of ETTs fell outside our desired tip to carina range compared to 47% of ETTs with the topographical method (p=0.010). No correlation was found between the topographical measurements and airway length (upper incisors to vocal cords) (r=0.248). Conclusions: Topographical measurements were not re-confirmed as an accurate intubation method and were found to be less reliable than the 21/23 method. We maintain that regardless of ETT insertion method utilized, the gold standard to ensure accurate ETT placement is fiberoptic inspection.

In Reply

We read with great interest the letter from El-Ganzouri and Ads. They made helpful comments on our report.1It is unfortunate that we did not mention why the complications were developed.The infant at 33-weeks gestation who weighed 2,050 g was delivered at a private hospital. At birth, the baby was dyspneic, and tracheal intubation was attempted by a physician who lacked much experience in neonatal intubation. An endotracheal tube was inserted into the esophagus three times, resulting in marked abdominal distension. Tracheal intubation was successful on the fourth attempt. After 80 min of ventilator care, the baby was tachycardic with an oxygen saturation of 80–90%. He was transferred to our hospital.I agree that these complications were made more likely by the prior esophageal intubations by a less experienced clinician.However, all hospitals, especially private hospitals, don't have experts in airway management available at all times.The main message of our report remains that immediately after intubation, adequate placement and depth of the endotracheal tube should be confirmed using end-tidal carbon dioxide, auscultation, endotracheal tube depth, and chest x-ray.

Can Novice Sonographers Accurately Locate an Endotracheal Tube With a Saline‐filled Cuff in a Cadaver Model? A Pilot Study

No single confirmatory device can accurately distinguish between endotracheal, endobronchial, and esophageal intubation. Bedside ultrasound (US) shows promising potential for endotracheal tube (ETT) verification. Image acquisition depends on the approach used and the experience of the sonographer. Air within the trachea remains a challenge for interpretation of US images. Insufflation of the ETT cuff with saline helps overcome this difficulty and allows easy visualization of the cuff. This novel approach has not been studied in ETT verification among novice sonographers. The objective was to evaluate the accuracy of novice sonographers in identifying proper ETT location and depth using US visualization of a saline-filled cuff. Eight pediatric emergency medicine (PEM) fellows without prior training in airway bedside US participated in this prospective pilot study. Baseline US knowledge was assessed using a pretraining questionnaire. Fellows received a 20-minute didactic training session focused on airway US, followed by a 30-minute practice session. Using a linear US probe placed at the suprasternal notch, fellows identified the saline-filled cuff of an ETT in both the trachea and the esophagus. Following training, the ETT was placed in either the esophagus or the trachea of the cadaver model by the principal investigator. ETT depth (adequacy) was confirmed by chest radiograph. Each PEM fellow, blinded to the placement of the ETT, used bedside US to determine ETT location and depth. If placement was determined to be tracheal, the fellow was asked to comment on adequacy of tube placement. Adequate placement was defined as complete visualization of the ETT cuff within the trachea at the suprasternal notch. This was used as a surrogate for correct depth. This study sequence was repeated five times for each trainee, following varying placement of the ETT in the trachea or esophagus. The PEM fellows displayed limited baseline knowledge of US prior to receiving the training module (average score of 50% on pretest questionnaire). None had any prior airway bedside US experience. Following training, PEM fellows correctly identified ETT location in 39 of 40 scans, with a sensitivity of 96% (23 of 24) for identifying tracheal location. The tube depth was correctly identified in 22 of 23 scans identified as tracheal intubations. PEM fellows, lacking formal airway bedside US training, were able to identify the location and depth of a saline-filled ETT above or at the suprasternal notch in an adult cadaver model following a 50-minute teaching module. Filling the ETT cuff with saline allowed novice sonographers to accurately visualize the ETT within the trachea.

Tension pneumothorax after ultrasound guided internal jugular venous catheterization in an inadvertently endobronchially intubated patient with kyphosis

Tension pneumothorax after ultrasound guided internal jugular venous catheterization in an inadvertently endobronchially intubated patient with kyphosis

Endobronchial intubation detected by insertion depth of endotracheal tube, bilateral auscultation, or observation of chest movements: randomised trial

Endobronchial intubation detected by insertion depth of endotracheal tube, bilateral auscultation, or observation of chest movements: randomised trial

Two Complications of Tracheal Intubation in a Neonate

AN infant delivered in a private hospital after 33 weeks' gestation weighed 2,050 g, had persistent tachypnea, and had associated hypoxia requiring intubation. After three esophageal intubations, the neonate's trachea was successfully intubated. Despite mechanical ventilation, the infant had persistent tachycardia, hypoxemia (80–90% oxygen saturation) and a distended abdomen. A preoperative radiograph of this child shows the endotracheal tube tip in the right main bronchus (arrow A ), atelectasis of the entire left lung (arrow B ), pneumoperitoneum (white arrows ), and increased abdominal gas. At surgery, a 1.5-cm perforation of the anterior wall of the lesser curvature of the stomach was identified and repaired.The radiograph emphasizes critical complications that can occur during airway management of a neonate. Inadvertent esophageal intubation is one of the most common causes of neonatal intubation failure, which can lead to catastrophic consequences.1This condition can be rapidly detected by using end-tidal carbon dioxide monitoring, because it is the single most useful method in confirming endotracheal tube position.2In this neonate, gastric perforation likely occurred as a result of distension associated with positive pressure ventilation after esophageal intubation. Endobronchial intubation is another common problem associated with airway management in a neonate. This child's atelectasis likely developed after main stem intubation, when the endotracheal tube depth was noted to be 11 cm. As a guide to proper tracheal placement of an endotracheal tube, 1-, 2-, or 3-kg babies are intubated to a depth of 7, 8, or 9 cm, respectively.3These two complications reinforce the need for specialized training and experience in neonatal airway management.

Accuracy of 7-8-9 Rule for Endotracheal Tube Placement in Nepalese Neonates

Introduction: Neonatal intubation is done for cardiopulmonary resuscitation, hypoxemia, and hypercapnia, for surfactant therapy or for airway protection. When correctly placed, endotracheal tube (ETT) tip should be at mid tracheal position which is half way between the clavicles and the carina to prevent complications of ventilation. Objective: To assess the accuracy of 7-8-9 Rule in neonates at Kanti Children’s hospital. Methodology: Prospective observational study was conducted in neonates who required oral intubations from July 2009 to December 2009 at NICU of Kanti Children’s Hospital. The initial ETT depth of insertion was determined using admission weight in the 7-8-9 Rule calculation. This depth was compared to the midtracheal depth to determine clinical accuracy of the 7-8-9 Rule. Results: Mean gestation age of the 69 infants was 36.01 weeks (26 to 42 weeks) and weight was 2411 g( 900 g to 3800 g ). 7 (10.1%) neonates weighed 1000 g or less, 19 (27.5%) weighed between 1001 to 2000 g, 31 ( 44.9%) weighed between 2001 to 3000 g, 12(17.4%) weighed between 3001 to 4000 g. The accuracy of 7-8-9 rule in clinical setting with auscultation and Chest x-ray resulted in ETT depth 0.11 cm above midtracheal position. (-1.5 to 1.5 cm). Using this rule ET tube was placed 0.11 cm above the mid tracheal position. Conclusions: The 7-8-9 Rule appears to be an accurate clinical method for endotracheal tube placement in Nepalese neonates. Keywords: Intubation; Neonate; Mid Tracheal Position DOI: http://dx.doi.org/10.3126/jnps.v31i3.4299 J Nep Paedtr Soc 2011;31(3): 175-179

Appropriate depth of placement of oral endotracheal tube and its possible determinants in Indian adult patients

Background:Optimal depth of endotracheal tube (ET) placement has been a serious concern because of the complications associated with its malposition.Aims:To find the optimal depth of placement of oral ET in Indian adult patients and its possible determinants viz. height, weight, arm span and vertebral column length.Settings and Design:This study was conducted in 200 ASA I and II patients requiring general anaesthesia and orotracheal intubation.Methods:After placing the ET with the designated black mark at vocal cords, various airway distances were measured from the right angle of mouth using a fibre optic bronchoscope.Statistical Analysis:The power of the study is 0.9. Mean (SD) and median (range) of various parameters and Pearson correlation coefficient was calculated.Results:The mean (SD) lip-carina distance, i.e., total airway length was 24.32 (1.81) cm and 21.62 (1.34) cm in males and females, respectively. With black mark of ET between vocal cords, the mean (SD) ET tip-carina distance of 3.69 (1.65) cm in males and 2.28 (1.55) cm females was found to be considerably less than the recommended safe distance.Conclusions:Fixing the tube at recommended 23 cm in males and 21 cm in females will lead to carinal stimulation or endobronchial placement in many Indian patients. The lip to carina distance best correlates with patient's height. Positioning the ET tip 4 cm above carina as recommended will result in placement of tube cuff inside cricoid ring with currently available tubes. Optimal depth of ET placement can be estimated by the formula “(Height in cm/7)-2.5.”

Utilizing Nasal-Tragus Length to Estimate Optimal Endotracheal Tube Depth for Neonates in Taiwan

To assess the application of the nasal-tragus length (NTL) to predict the proper endotracheal tube (ETT) depth; also, as relatively thinner size of Asian than Caucasian, the fitness of using the NTL to estimate the optimal ETT depth for neonates in Taiwan was examined. The newborn infants who do need intubation orally were included. Those with midface dysmorphism, craniofacial anomalies, head trauma and/or facial injury in whom it was unable to measure NTL, were excluded. The data were collected after a satisfactory ETT tip position was confirmed on chest roentgenogram. Equations were established via the polynomial and the linear regression of the NTL and the actual ETT; simplified formulae as NTL+0.5 and NTL+1 were assumed accordingly. Paired t test was used to assess the coefficients. The 63 neonates, weighing 410 through 4,196 g and with gestation 21 through 41 weeks, were enrolled. No statistical difference was found between the actual ETT depth and the estimated ETT depth via the NTL+1 cm in neonates weighing ≤ 2,500 g (n=41, p=0.06), and also between the actual ETT depth and the estimated ETT depth via the NTL+0.5 cm in group weighing >2,500 g (n=22, p=0.171). Using the NTL to predict the optimal ETT depth with the formula, NTL plus 1 cm, was clinically practical for newborn infants in Taiwan weighing ≤ 2,500 g, and a modified formula, NTL plus 0.5 cm, was more suitable for neonates weighing >2,500 g.

Airway obstruction by extrinsic tracheal compression during spinal surgery under prone position -A case report-

Tracheal compression by vascular anomalies in adults is uncommon and most related reports are of children. A 79-year-old woman without any respiratory history underwent a lumbar spine surgery under general anesthesia. She suddenly developed airway obstruction after a position change from supine to prone. A fiberoptic bronchoscopy showed the obstruction of endotracheal tube. The obstruction was relieved after we changed the depth of endotracheal tube and supported the patient's neck with a cotton roll. The surgery ended without any other event and the patient recovered safely. A computed tomography revealed the rightward tracheal deviation and tortuous innominate artery contact with trachea. The patient didn't manifest any respiratory related symptoms during postoperative period, and she was discharged without any treatment.

Assessment of airway length of Korean adults and children for otolaryngology and ophthalmic surgery using a fiberoptic bronchoscope

BackgroundKnowledge regarding normal upper airway anatomy is essential for airway management and is required to prevent malpositioning of endotracheal tubes. We evaluated the length of the upper airway in Korean children and adults who had no abnormality of the upper airway using a fiberoptic bronchoscope.MethodsEighty seven patients aged 5 to 81 years undergoing noninvasive elective surgery were included in this study. After induction of anesthesia was complete, we measured the distance from the upper incisor to various components of the upper airway by fiberoptic bronchoscopy.ResultsIn adults, the mean length between the upper incisor and midtrachea was found to be 21.8 ± 1.8 cm in males and 19.9 ± 1.3 cm in females, while the mean length of the trachea was 10.1 ± 1.3 cm in males and 10.3 ± 1.6 cm in females. The length between the upper incisor and midtrachea (IT) were correlated with height both in children (IT [cm] = 2.531 + 0.109 × height [cm]) and adults (IT [cm] = 0.167 + 0.127 × height [cm]), which shows that they differ from the western standard (length of tube [cm] = 5 + 0.1 × height [cm]).ConclusionsIn adults and children, the length from the incisor to the midtrachea was significantly different when compared with western standards. Therefore, re-evaluation of the proper and precise depth of endotracheal tube in Koreans should be considered.

Endobronchial intubation detected by insertion depth of endotracheal tube, bilateral auscultation, or observation of chest movements: randomised trial

Objective To determine which bedside method of detecting inadvertent endobronchial intubation in adults has the highest sensitivity and specificity.Design Prospective randomised blinded study.Setting Department of anaesthesia in tertiary academic hospital.Participants...

Appropriate Endotracheal Tube Placement in Children: Don’t Throw Away Your Stethoscopes Yet!

We read with interest the recent article by Dr. Hunyady and colleagues.1While we acknowledge that mathematical formulae based on morphometric data may be useful guides, we caution against applying these formulae in lieu of clinical assessment. We conducted a randomized clinical trial to compare three common methods of endotracheal tube (ETT) placement: 1) deliberate mainstem intubation with subsequent withdrawal of the ETT 2 cm above the carina (“mainstem” method); 2) alignment of the double black line marker near the ETT tip at the vocal cords (“marker” method); or 3) placement of the ETT at a depth determined by the formula: ETT depth (cm) = 3 times ETT size (mmID) (“formula” method).2In our study, the formula method only placed the ETT at the appropriate depth 42% of the time. In addition, we retrospectively evaluated the efficacy of another formula, ETT depth (cm) = Age(yrs)/2 + 12,3but appropriate placement would have been achieved only 42% of the time as well. Identification of the carina via auscultation, the mainstem method, was the preferred technique (73%, P = 0.006 vs. the formula method).2Although our study did not specifically examine the efficacy of the Morgan and Steward formula,4neither did the study by Hunyady et al. 1The authors’ conclusion that the “.t.t.tMorgan formula provides good guidance for intubation in children .t.t.” is extrapolated based on their measurements and calculations.1The authors do not specify which technique was used to initially determine ETT depth in their study subjects or report the rates of correct versus incorrect placement for the actual placement methods used. Based on the estimates by Hunyady et al. , the Morgan and Steward formula would have placed the ETT tip on average at the 90thpercentile for front teeth-to-carina distance and < 0.5 cm from the carina in 13 of their youngest subjects.1This is concerning since, as the authors astutely point out, the ETT is subject to movement with neck flexion or extension which may result in inadvertent endobronchial ETT placement.5–7Auscultation methods have their limitations as well,2,3and no clinical technique results in 100% success. When ETT placement is in question or when accurate ETT depth is mandatory for a particular surgical procedure (i.e. , prone position or head and neck surgery), we recommend intraoperative chest radiography, fluoroscopy, or fiberoptic bronchoscopy.*University of California, San Diego Medical Center, San Diego, California. ermariano@ucsd.edu

Evaluation of Manual Cuff Palpation to Confirm Proper Endotracheal Tube Depth

In the prehospital setting, optimal endotracheal tube (ETT) depth may be approximated using the patient's sex or height, and assessed by auscultation. Even when using these methods, the ETTs still may be placed at inappropriate depths. This study assessed the inter-rater reliability and accuracy of manual cuff palpation (ballottement) at excluding an improperly placed ETT depth in adult patients. This is a prospective, observational, pilot study in a convenience sample of adults recently intubated in the prehospital, medical floor, intensive care unit, or emergency department settings of an urban, teaching hospital. Two physician participants separately performed ballottement on each intubated subject and rated the ballottement as none, weak, or strong prior to assessment of appropriate depth using a chest radiograph (CXR). Results were compared for simple agreement and compared to the CXR to estimate accuracy. Of 163 patients, 27 (17%) had an inappropriate ETT depth. Physician assessments of ballottement agreed in 79% of patients (95% CI = 72-85%). Chest radiograph assessment found the ETT in the "strong" ballottement group properly placed in 93%, as compared to 77% in the "weak", and 42% in the "none" groups. Combining "weak" and "strong" ballottement, the sensitivity was 96% (95% CI = 93-100%), specificity was 26% (95% CI = 9-43%), and accuracy was 85% (95% CI = 79-90%). Manual cuff palpation is a simple and reproducible technique that is sensitive, but nonspecific, in identifying intubations of appropriate depth.

Optimal Depth of NIM EMG Endotracheal Tube for Intraoperative Neuromonitoring of the Recurrent Laryngeal Nerve During Thyroidectomy

Malpositioning of the endotracheal surface electrodes can result in dysfunction of intraoperative neuromonitoring (IONM) and increase the risk of recurrent laryngeal nerve injury. The purpose of this study was to investigate the optimal depth of the nerve integrity monitor (NIM) EMG endotracheal tube. We enrolled 105 adult patients undergoing elective thyroidectomy. Each Medtronic Xomed NIM EMG endotracheal tube was placed with the middle of the exposed electrodes well in contact with the true vocal cords under direct laryngoscopy. Function of IONM was documented and the insertion depth was measured and analyzed. Ninety-nine (94.3%) patients had successful IONM with the initial endotracheal tube position. Six (5.7%) patients needed further tube depth adjustment under fiberoptic bronchoscopy. All patients were finally had successful IONM. The optimal mean depth was 20.6 +/- 0.97 cm in men and 19.6 +/- 1.0 cm in women (p < 0.01). There was the trend that taller subjects had a deeper tube depth (p < 0.05). We concluded that the mean depth of the NIM EMG tube would be a useful reference value for detecting the malposition of electrodes and adjusting the depth of tube during the operation.

An Observational Study of Anesthesia Record Completeness Using an Anesthesia Information Management System

Studies of the accuracy and completeness of handwritten anesthesia records demonstrate deficiencies in documentation, suggesting that the quality of anesthesia records can be improved. We reviewed all electronic anesthesia records generated during a 1-month period at our institution to ascertain completion rates for six clinical documentation elements: allergies, IV access, electrocardiogram rhythm, ease of mask ventilation, laryngoscopic grade of view, and insertion depth of the endotracheal tube. Of 2838 records, 64% had the necessary free text remark in the allergy element. The free text required to complete endotracheal tube depth documentation appeared in 538 of 918 cases in which the patient was tracheally intubated (59%). Free text documentation of the electrocardiogram rhythm diagnosis appeared at least once in 86% of records. Documentation of mask ventilation characteristics was entered by touch screen from a pick list and was expected in 781 records but appeared in 664 records (85%). Laryngoscopic grade of view documentation was also selected by touch screen and expected in 883 records but present in 811 cases (92%). Any notation of IV access appeared in 84% of records. We found that electronic clinical anesthesia documentation was often incomplete. Dependence on free text remarks and the record keeping system's inability to automatically present entries in logical sequences consistent with workflow were associated with incomplete data entry. Our results suggest that the user interface for data entry, and the logic that an electronic system uses for preventing omissions and inconsistencies, merit further study and development in order to facilitate clinically useful documentation.

Accuracy of the 7-8-9 Rule for endotracheal tube placement in the neonate

To determine accuracy of the 7-8-9 Rule in a cohort of neonates. This study was cross-sectional in design. Seventy-five consecutive neonates who required oral intubation from June 2004 to November 2004 for cardiopulmonary failure, respiratory distress, or surfactant administration were the subjects of this study. The initial endotracheal tube (ETT) depth of insertion was determined using either an estimated birth weight or actual weight in the 7-8-9 Rule calculation followed by auscultation and subsequent adjustment if necessary. Midtracheal position was identified as the point halfway between the inferior clavicle and carina on a chest radiograph. The initial depth was compared to the midtracheal depth to determine clinical accuracy of the 7-8-9 Rule. The depth predicted by the 7-8-9 Rule was also calculated using only actual weights. This predicted depth was compared to the midtracheal depth to determine true accuracy of the 7-8-9 Rule. Accuracy was determined using mean paired differences with 95% confidence intervals (CI) between initial or predicted depth and ideal, midtracheal ETT depth. Linear regression was used to adjust for confounding variables. Mean (range) gestational age was 32 weeks (23 to 44 weeks) and weight was 2001 g (490 to 4400 g). Eighteen (24%) infants weighed 1000 g or less, 20 (27%) weighed between 1001 and 2000 g, 21 (28%) weighed between 2001 and 3000 g, 15 (20%) weighed between 3001 and 4000 g, and one (1%) weighed more than 4000 g. Thirteen of the 18 extremely low birth weight infants weighed <750 g. The initial depth of insertion was 0.004 cm above midtracheal position (95% CI -0.13 to 0.14, P = 0.96). After controlling for head position, the initial depth did not significantly differ from the midtracheal position among weight groups. Predicted depth using the 7-8-9 Rule placed the ETT 0.12 cm above midtracheal position (95% CI -0.30 to 0.06, P = 0.20). However, after controlling for head position, the 7-8-9 Rule positioned the ETT significantly below midtracheal position in infants weighing <750 g (mean 0.62 cm; 95% CI 0.30 to 0.93, P=0.002). The 7-8-9 Rule appears to be an accurate clinical method for endotracheal tube placement in neonates weighing more than 750 g. When the 7-8-9 Rule is applied to infants weighing <750 g, caution is warranted. The current rule may lead to an overestimated depth of insertion and potentially result in clinically significant consequences.