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Endotracheal tube position in the infant
June, 1971 T h e Journal of P E D I A T R I C S
99I
Endotracbeal tube position in the infant The locations of endotracheal tubes were assessed radiographicaUy in 36 of 52 intubated infants during a 1 ~ year period. In 18 of the 36 patients for whom there were radiographs, the endotracheal tubes were in one of the bronchi. Eleven of these 18 patients developed atelectasis. The effects of head motion and respiration on the position of the tube were also evaluated. Suggestions are given to ensure proper placement of an endotracheal tube and for maintenance of the tube in the trachea.
Lawrence R. Kuhns, M.D., * and Andrew K. Poznanski, M.D. ANN
ARBOR,
I N T U B A T I O N
MICI-I.
during emergency r e s u s -
is fraught with many hazards. The endotracheal tube may be placed outside of the trachea in the esophagus (Fig. 1), or it may become occluded during passage through the nose or trachea by blood and mucus? Probably the most common complication of emergency endotracheal tube placement is lodgment of the tube tip in a main bronchus. This may lead to hypoaeration of certain lobes of the lung and overexpansion of others. 2, a In series of adult patients, this complication has occurred in 10 to 50 per cent of patients intubated. ~, 5 At the C. S. Mott Children's Hospital auscultation of the chest is routine after endotracheal tube placement. However, auscultation is said to be deceptive in positioning the endotracheal tube2 Chest radiography is the only certain way of demonstrating its position. To our knowledge, until now, no systematic study has been performed regarding the incidence of improper location citation
From the Department of Radiology, The University of Michigan. *Address: Divls~on o[ Pediatric Radiology, C. S. Mott Children's Hospital, Ann Arbor, Mich. 48104.
of the endotracheal tube in the pediatric age group. MATERIALS AND METHODS Most of the emergency intubations in the C. S. Mott Children's Hospital are performed on children less than one year of age; the present study was restricted to this age group. Every attempt is made to obtain radiographs as soon as possible after intubation. All pre- and postintubation radiographs were evaluated during the period from January 1, 1969, to June 30, 1970. During this time 847 patients were admitted to the infant ward and 52 (6.1 per cent) received emergency intubadon. Two patients were intubated with Cole (Smith's Industries, Inc., Woburn, Mass.) tubes and the others with Portex (Foregger Hospital Equipment, Smithtown, N. Y.) tubes varying in diameter from 3 to 6 ram. All intubations were performed by pediatric interns and residents on infants with life-threatening respiratory emergencies. Auscultation of the chest was routinely performed after each intubation in order to ascertain that both lungs were aerated. Sixteen infants did not receive postVol. 78, No. 6, pp. 991-996
99 2
Kuhns and Poznanski
intubation radiographs; of these, 9 were pronounced dead within minutes of the start of resuscitation, 3 were resuscitated and the tube was immediately withdrawn, and 2 were taken immediately to surgery. In 3 infants, the effect of head movement
The Journal o[ Pediatrics June 1971
on position of the endotracheal tube tip was evaluated radiographically. In 3 other patients the movement of the carina in relation to the tip of the endotracheal tube during all phases of respiration was assessed during venous angiocardiography. RESULTS
Fig. 1. Endotracheal tube in esophagus, posterior to tracheal air shadow (tube tip marked by black line).
Fifty-two infants were intubated during the time of the study. Most received orotracheal tubes and a few had nasotracheal tubes. Thirty-six had postintubation radiographs within 15 minutes to several hours after intubation and daily follow-up films. In 18 infants for whom there were chest radiographs, the endotracheal tube was located beyond the carina. In 14 the tip of the endotracheal tube was shown to be within the right main bronchus or the bronchus intermedius by the first film after intubation (Fig. 2). In 3 patients, serial chest radiographs showed progressive descent of orotracheal tubes over several days into the right main bronchus. In only one was the tube in the left main bronchus (Fig. 3). In this instance a curved stylet had been used to help insert the tube. (Since the time of this study,
Fig. 2. Endotracheal tube with tip 2 era. beyond the carina (tip marked by black line). Atelectasis of left lung and right upper lobe occurred after intubation.
Volume 78
Endotracheal tube position
Number 6
99 3
2 hours, 2 89 hours, and 2 days, respectively. In 8 instances the atelectatic lung never re-expanded despite withdrawal of the tubes into the trachea. There was no significant difference in the survival of the patients with endobronchial intubation as compared to that of those with endotracheal intubation (Table I I ) . No pneumothorax was observed
we have witnessed an additional left bronchial intubation; this one was also associated with the use of a stylet.) No endotracheal tube was found to be in the esophagus during this study. Rapid radiologic interpretation of all emergency bedside chest films was given to the ward pediatrician so that he usually knew the exact position of the endotracheal tube within minutes after radiography. There was no significant difference in the ages of the patients in whom the tip of the tube was in the trachea as compared to those in whom the tube was in a bronchus. The average width of the endotracheal tubes located in the trachea did not differ statistically from the width of those located in a bronchus. A 5 mm. tube was able to descend into the bronchus of a premature infant. Atelectasis occurred in 11 of the 18 patients following endobronchial intubation; the site is shown in Table I. Atelectasis developed only in patients in whom the tube extended more than ~ cm. into the bronchus. Following withdrawal of the tube to a level above the carina, the atelectatic lung re-expanded completely in 3 patients within
Table I. Relationship of endotracheal tube placement to site of atelectasis Tube tip In trachea Barely in right main bronchus Greater than 89 cm. into right main bronchus
No. of patients 18 7 10
Ateleetasis None after intubation None Entire left lung (5) Left upper lobe (2) Right upper lobe
(1) Combinations of above (2) Left main stem bronchus
1
Entire right lung
!
1192768 Fig. 3. Endotracheal tube lodged in left main bronchus with loss of volume of right lung and overexpansion of leftlung (tip marked by black line).
9 9 4 Kuhns and Poznanskl
The Journal o[ Pediatrics June 1971
A
B
C
Fig. 4. A, Endotracheal tube in the trachea and head in neutral position. Note relationship of tube tip (marked by short line) to the sixth vertebral body (marked by long line). B, Head in maximum flexion. The endotracheal tube tip has descended in the trachea. C, Position of the tube tip with the head turned maximally to one side. Note that the tube tip has moved eephalad. The endotracheal tube had been securely fastened to the head and did not move in relation to the head during these maneuvers.
Table II. Survival related to endotracheal tube position
Position
ISurvivedl Died I T o t a l
Tube in bronchus 5 Tube in trachea 8 Total 13 Xz = 188. P < 0.2: no significantdifference.
13 10 23
18 18 36
relation to the thoracic spine. During flexion of the neck, the tip of the tube advanced caudad a m a x i m u m of 0.5 cm., and when the head was turned to the side the tip was pulled u p w a r d a m a x i m u m of 1.2 em. as compared to the neutral position (Fig. 4). These observations extend those of a previously reported study. 8 DISCUSSION
in the hyperexpanded lung of the patients with endobronchial intubation. During venous angiocardiography on 3 infants, tile carina was seen to move 0.5 to 2.0 cm. in relation to the tip of the endotracheal tube during respiration. I n 3 neonates, movement of the infant's head with the endotracheal tube in place altered the position of the tip of the tube in
This study documents the end result of tube position at the time of radiography in 36 infants receiving emergency intubation. I n one half of these infants the tube was in a bronchus at the time of the initial radiograph. T h e distance from the larynx to the carina of only 5.7 cm. in the average living neonate 6 allows little margin of error in placing the tube. T h e tip of the tube should
Volume 78 Number 6
Endotracheal tube position
995
Fig. 5. Note 9 cm. mark on the intubator's left index finger by which the correct endotracheal tube length can be quickly determined just before intubation.
be at least 1.2 cm. below the vocal cords with the head in neutral position so that it will not be pulled out of the trachea during head turning. It should not be within 2 cm. of the carina as it may enter a bronchus during expiration. Thus only a 2.5 cm. "safety zone" for the tube tip exists in the trachea of the newborn infant. The tendency is for the endotracheal tube to be located too distally. After an endotracheal tube is placed through the mouth, it may gradually descend into a bronchus, as it did in 3 of our patients, because it is difficult to adequately secure it. When the tube is in a bronchus, some ventilation of the side opposite the tube tip may occur by air escaping around the endotracheal tube so that breath sounds may be heard over the lung of the unobstructed bronchus. T h e lung opposite the endotracheal tube may, however, become atelectatic because of hypoventilation or accumulation of secretions. Charts are available for determining proper lengths of nasotracheal tul~es for use in neonates; they are probably adequate for orotracheal intubafion. ~ However, during emergency intubation there is seldom time to calculate the length of tube which must be
inserted. In 12 of our patients, the head in neutral position was included in the lateral radiograph of the chest which was taken at a 40 inch tube-film distance with the patient lying directly on the film cassette. Using a magnification factor of 6 per cent, measurements of the distances along the tubes from the lips to 2 cm. above the carina on the lateral chest radiographs indicate that a tube length of 9 cm. would have been appropriate in 10 of the 12 infants. In one, a 29-week-old premature infant, a length of 7 cm. would have been appropriate; in the other one, a 9-month-old infant, a 12.0 cm. tube would have been optimal. T h e point 2 cm. above the carina was chosen as the m a x i m u m distance to which the endotracheal tube should be inserted because of the tube-carina relationships during respiration. A tube length of 9 cm. for a near-term infant would place the tip of the tube well beyond the laryngeal cords so that the tube would not be pulled out of the trachea by head motion. We think that manufacturers of endotracheal tubes should place centimeter markings on all endotracheal tubes. To our knowledge, no tubes have this type of marking. If the pediatrician will learn to recognize a 9
99 6
Kuhns and Poznanski
cm. landmark on his finger (Fig. 5), he can quickly mark this distance on the endotracheal tube just before emergency intubation to determine the distance it should be inserted for the term infant. For the very small premature infant, 2 cm. can be subtracted, and for the one-year-old infant 2 cm. can be added to this distance. The lettering on endotraeheal tubes should not be relied upon to gauge distance from the tip of the tube. The position of the lettering with respect to the tip varies in tubes of different width. Chest radiographs at the bedside should be obtained routinely immediateIy after intubation and daily thereafter to determine the position of the tube, and the report of each radiograph should reach the pediatrician as soon as possible. The chests of patients who are intubated should be auscultated frequently to detect subtle changes in ventilation. In this way the endotracheal tube can be placed in good position with certainty, and ateleetasis with its complications can be avoided. The authors wish to thank Dr. William Oliver, Chairman of the Department of Pediatrics and
The Journal of Pediatrics June 1971
Communicable Diseases, and Dr. Walter Whitehouse, Chairman of the Department of Radiology, for reviewing the manuscript and for their constructive suggestions. REFERENCES
1. Bamforth, B. J.: Complications during endotracheal anesthesia, Anesth. Analg. 42: 727, 1963. 2. Twlgg, H. L., and Buekley, C. E.: Complications of endotracheal intubation, Amer. J. Roentgen. 109: 452, 1970. 3. Tisi, G. M., Twigg, H. L., and Moser, K. M.: Collapse of left lung induced by artificial airway, Lancet 1: 791, 1968. 4. Bergstrom, J.: Intubation and tracheotomy in barbiturate poisoning, in Johansen, S. H., editor: International Anesthesiology Clinic, Barbiturate poisoning and tetanus, vol. 4, No. 2, Boston, 1966, Little, Brown & Company. 5. Heinonen, J., Takki, S., and Tammisto, T.: Effect of the Trendelenburg tiIt and other procedures on the position of endotracheal tubes, Lancet 1: 850, 1969. 6. Fearon, B., and Whalen, J. S.: Tracheal dimensions in the living infant: Preliminary report, Ann. Otol. 76: 964, 1967. 7. Coldiron, J. S.: Estimation of nasotracheal tube length in neonates, Pediatrics 41: 823, 1968. 8. Alberti, J., Hanafee, W., Wilson, G., and Bethune, R.: Unsuspected pulmonary collapse during neuroradiologlcal procedures, Radiology 89: 316, 1967.
99I
Endotracbeal tube position in the infant The locations of endotracheal tubes were assessed radiographicaUy in 36 of 52 intubated infants during a 1 ~ year period. In 18 of the 36 patients for whom there were radiographs, the endotracheal tubes were in one of the bronchi. Eleven of these 18 patients developed atelectasis. The effects of head motion and respiration on the position of the tube were also evaluated. Suggestions are given to ensure proper placement of an endotracheal tube and for maintenance of the tube in the trachea.
Lawrence R. Kuhns, M.D., * and Andrew K. Poznanski, M.D. ANN
ARBOR,
I N T U B A T I O N
MICI-I.
during emergency r e s u s -
is fraught with many hazards. The endotracheal tube may be placed outside of the trachea in the esophagus (Fig. 1), or it may become occluded during passage through the nose or trachea by blood and mucus? Probably the most common complication of emergency endotracheal tube placement is lodgment of the tube tip in a main bronchus. This may lead to hypoaeration of certain lobes of the lung and overexpansion of others. 2, a In series of adult patients, this complication has occurred in 10 to 50 per cent of patients intubated. ~, 5 At the C. S. Mott Children's Hospital auscultation of the chest is routine after endotracheal tube placement. However, auscultation is said to be deceptive in positioning the endotracheal tube2 Chest radiography is the only certain way of demonstrating its position. To our knowledge, until now, no systematic study has been performed regarding the incidence of improper location citation
From the Department of Radiology, The University of Michigan. *Address: Divls~on o[ Pediatric Radiology, C. S. Mott Children's Hospital, Ann Arbor, Mich. 48104.
of the endotracheal tube in the pediatric age group. MATERIALS AND METHODS Most of the emergency intubations in the C. S. Mott Children's Hospital are performed on children less than one year of age; the present study was restricted to this age group. Every attempt is made to obtain radiographs as soon as possible after intubation. All pre- and postintubation radiographs were evaluated during the period from January 1, 1969, to June 30, 1970. During this time 847 patients were admitted to the infant ward and 52 (6.1 per cent) received emergency intubadon. Two patients were intubated with Cole (Smith's Industries, Inc., Woburn, Mass.) tubes and the others with Portex (Foregger Hospital Equipment, Smithtown, N. Y.) tubes varying in diameter from 3 to 6 ram. All intubations were performed by pediatric interns and residents on infants with life-threatening respiratory emergencies. Auscultation of the chest was routinely performed after each intubation in order to ascertain that both lungs were aerated. Sixteen infants did not receive postVol. 78, No. 6, pp. 991-996
99 2
Kuhns and Poznanski
intubation radiographs; of these, 9 were pronounced dead within minutes of the start of resuscitation, 3 were resuscitated and the tube was immediately withdrawn, and 2 were taken immediately to surgery. In 3 infants, the effect of head movement
The Journal o[ Pediatrics June 1971
on position of the endotracheal tube tip was evaluated radiographically. In 3 other patients the movement of the carina in relation to the tip of the endotracheal tube during all phases of respiration was assessed during venous angiocardiography. RESULTS
Fig. 1. Endotracheal tube in esophagus, posterior to tracheal air shadow (tube tip marked by black line).
Fifty-two infants were intubated during the time of the study. Most received orotracheal tubes and a few had nasotracheal tubes. Thirty-six had postintubation radiographs within 15 minutes to several hours after intubation and daily follow-up films. In 18 infants for whom there were chest radiographs, the endotracheal tube was located beyond the carina. In 14 the tip of the endotracheal tube was shown to be within the right main bronchus or the bronchus intermedius by the first film after intubation (Fig. 2). In 3 patients, serial chest radiographs showed progressive descent of orotracheal tubes over several days into the right main bronchus. In only one was the tube in the left main bronchus (Fig. 3). In this instance a curved stylet had been used to help insert the tube. (Since the time of this study,
Fig. 2. Endotracheal tube with tip 2 era. beyond the carina (tip marked by black line). Atelectasis of left lung and right upper lobe occurred after intubation.
Volume 78
Endotracheal tube position
Number 6
99 3
2 hours, 2 89 hours, and 2 days, respectively. In 8 instances the atelectatic lung never re-expanded despite withdrawal of the tubes into the trachea. There was no significant difference in the survival of the patients with endobronchial intubation as compared to that of those with endotracheal intubation (Table I I ) . No pneumothorax was observed
we have witnessed an additional left bronchial intubation; this one was also associated with the use of a stylet.) No endotracheal tube was found to be in the esophagus during this study. Rapid radiologic interpretation of all emergency bedside chest films was given to the ward pediatrician so that he usually knew the exact position of the endotracheal tube within minutes after radiography. There was no significant difference in the ages of the patients in whom the tip of the tube was in the trachea as compared to those in whom the tube was in a bronchus. The average width of the endotracheal tubes located in the trachea did not differ statistically from the width of those located in a bronchus. A 5 mm. tube was able to descend into the bronchus of a premature infant. Atelectasis occurred in 11 of the 18 patients following endobronchial intubation; the site is shown in Table I. Atelectasis developed only in patients in whom the tube extended more than ~ cm. into the bronchus. Following withdrawal of the tube to a level above the carina, the atelectatic lung re-expanded completely in 3 patients within
Table I. Relationship of endotracheal tube placement to site of atelectasis Tube tip In trachea Barely in right main bronchus Greater than 89 cm. into right main bronchus
No. of patients 18 7 10
Ateleetasis None after intubation None Entire left lung (5) Left upper lobe (2) Right upper lobe
(1) Combinations of above (2) Left main stem bronchus
1
Entire right lung
!
1192768 Fig. 3. Endotracheal tube lodged in left main bronchus with loss of volume of right lung and overexpansion of leftlung (tip marked by black line).
9 9 4 Kuhns and Poznanskl
The Journal o[ Pediatrics June 1971
A
B
C
Fig. 4. A, Endotracheal tube in the trachea and head in neutral position. Note relationship of tube tip (marked by short line) to the sixth vertebral body (marked by long line). B, Head in maximum flexion. The endotracheal tube tip has descended in the trachea. C, Position of the tube tip with the head turned maximally to one side. Note that the tube tip has moved eephalad. The endotracheal tube had been securely fastened to the head and did not move in relation to the head during these maneuvers.
Table II. Survival related to endotracheal tube position
Position
ISurvivedl Died I T o t a l
Tube in bronchus 5 Tube in trachea 8 Total 13 Xz = 188. P < 0.2: no significantdifference.
13 10 23
18 18 36
relation to the thoracic spine. During flexion of the neck, the tip of the tube advanced caudad a m a x i m u m of 0.5 cm., and when the head was turned to the side the tip was pulled u p w a r d a m a x i m u m of 1.2 em. as compared to the neutral position (Fig. 4). These observations extend those of a previously reported study. 8 DISCUSSION
in the hyperexpanded lung of the patients with endobronchial intubation. During venous angiocardiography on 3 infants, tile carina was seen to move 0.5 to 2.0 cm. in relation to the tip of the endotracheal tube during respiration. I n 3 neonates, movement of the infant's head with the endotracheal tube in place altered the position of the tip of the tube in
This study documents the end result of tube position at the time of radiography in 36 infants receiving emergency intubation. I n one half of these infants the tube was in a bronchus at the time of the initial radiograph. T h e distance from the larynx to the carina of only 5.7 cm. in the average living neonate 6 allows little margin of error in placing the tube. T h e tip of the tube should
Volume 78 Number 6
Endotracheal tube position
995
Fig. 5. Note 9 cm. mark on the intubator's left index finger by which the correct endotracheal tube length can be quickly determined just before intubation.
be at least 1.2 cm. below the vocal cords with the head in neutral position so that it will not be pulled out of the trachea during head turning. It should not be within 2 cm. of the carina as it may enter a bronchus during expiration. Thus only a 2.5 cm. "safety zone" for the tube tip exists in the trachea of the newborn infant. The tendency is for the endotracheal tube to be located too distally. After an endotracheal tube is placed through the mouth, it may gradually descend into a bronchus, as it did in 3 of our patients, because it is difficult to adequately secure it. When the tube is in a bronchus, some ventilation of the side opposite the tube tip may occur by air escaping around the endotracheal tube so that breath sounds may be heard over the lung of the unobstructed bronchus. T h e lung opposite the endotracheal tube may, however, become atelectatic because of hypoventilation or accumulation of secretions. Charts are available for determining proper lengths of nasotracheal tul~es for use in neonates; they are probably adequate for orotracheal intubafion. ~ However, during emergency intubation there is seldom time to calculate the length of tube which must be
inserted. In 12 of our patients, the head in neutral position was included in the lateral radiograph of the chest which was taken at a 40 inch tube-film distance with the patient lying directly on the film cassette. Using a magnification factor of 6 per cent, measurements of the distances along the tubes from the lips to 2 cm. above the carina on the lateral chest radiographs indicate that a tube length of 9 cm. would have been appropriate in 10 of the 12 infants. In one, a 29-week-old premature infant, a length of 7 cm. would have been appropriate; in the other one, a 9-month-old infant, a 12.0 cm. tube would have been optimal. T h e point 2 cm. above the carina was chosen as the m a x i m u m distance to which the endotracheal tube should be inserted because of the tube-carina relationships during respiration. A tube length of 9 cm. for a near-term infant would place the tip of the tube well beyond the laryngeal cords so that the tube would not be pulled out of the trachea by head motion. We think that manufacturers of endotracheal tubes should place centimeter markings on all endotracheal tubes. To our knowledge, no tubes have this type of marking. If the pediatrician will learn to recognize a 9
99 6
Kuhns and Poznanski
cm. landmark on his finger (Fig. 5), he can quickly mark this distance on the endotracheal tube just before emergency intubation to determine the distance it should be inserted for the term infant. For the very small premature infant, 2 cm. can be subtracted, and for the one-year-old infant 2 cm. can be added to this distance. The lettering on endotraeheal tubes should not be relied upon to gauge distance from the tip of the tube. The position of the lettering with respect to the tip varies in tubes of different width. Chest radiographs at the bedside should be obtained routinely immediateIy after intubation and daily thereafter to determine the position of the tube, and the report of each radiograph should reach the pediatrician as soon as possible. The chests of patients who are intubated should be auscultated frequently to detect subtle changes in ventilation. In this way the endotracheal tube can be placed in good position with certainty, and ateleetasis with its complications can be avoided. The authors wish to thank Dr. William Oliver, Chairman of the Department of Pediatrics and
The Journal of Pediatrics June 1971
Communicable Diseases, and Dr. Walter Whitehouse, Chairman of the Department of Radiology, for reviewing the manuscript and for their constructive suggestions. REFERENCES
1. Bamforth, B. J.: Complications during endotracheal anesthesia, Anesth. Analg. 42: 727, 1963. 2. Twlgg, H. L., and Buekley, C. E.: Complications of endotracheal intubation, Amer. J. Roentgen. 109: 452, 1970. 3. Tisi, G. M., Twigg, H. L., and Moser, K. M.: Collapse of left lung induced by artificial airway, Lancet 1: 791, 1968. 4. Bergstrom, J.: Intubation and tracheotomy in barbiturate poisoning, in Johansen, S. H., editor: International Anesthesiology Clinic, Barbiturate poisoning and tetanus, vol. 4, No. 2, Boston, 1966, Little, Brown & Company. 5. Heinonen, J., Takki, S., and Tammisto, T.: Effect of the Trendelenburg tiIt and other procedures on the position of endotracheal tubes, Lancet 1: 850, 1969. 6. Fearon, B., and Whalen, J. S.: Tracheal dimensions in the living infant: Preliminary report, Ann. Otol. 76: 964, 1967. 7. Coldiron, J. S.: Estimation of nasotracheal tube length in neonates, Pediatrics 41: 823, 1968. 8. Alberti, J., Hanafee, W., Wilson, G., and Bethune, R.: Unsuspected pulmonary collapse during neuroradiologlcal procedures, Radiology 89: 316, 1967.