CONCEPTS
endotracheal tube whistle
E
ndotracheal Tube Whistle" An Adjunct to
Blind Nasotracheal Intubation
From the Department of Emergency
Scott Krishel, MD*
Medicine, Maricopa Medical
Ken Jackimczyk, MD, FACEP* Kendra Balazs, RN, CCRNt
Center;* and Medical Flight Services, Samaritan AirEvac, t Phoenix, Arizona. Receivedfor publication May 8, 1991. Acceptedfor publication August 13, 1991.
JANUARY 1992 2 1 : 1 ANNALS OF EMERGENOY MEDICINE
To perform blind nasotracheal intubation, the physician feels or listens for air movement through the endotracheal tube to facilitate the tube's passage into the trachea. The tube whistle is a device that attaches to the endotracheal tube adapter and produces whistle sounds of different pitches during inspiration and expiration, enhancing the detection of air movement and possibly allowing for easier intubation. This article describes the use of the whistle and presents information collected from a nine-month prospective study of the endotracheal tube whistle. [Krishel S, Jackimczyk K, Balazs K: Endotracheal tube whistle: An adjunct to blind nasotracheal intubation. Ann Emerg Med January 1992;21:33-36.]
33/45
I
ENDOTRACHEAL TUBE WHISTLE
Krishel, Jackimczyk & Balazs
INTRODUCTION Emergency physicians routinely use orotracheal intubation, nasotracheal intubation, and cricothyrotomy to actively secure airways in the emergency setting. Use of blind nasotracheal intubation has an advantage in that it can be performed on awake, spontaneously breathing patients without inducing paralysis. Blind nasotracheal intubation requires the physician to note air movement while inserting the tube into the trachea. Any device that improves the ability to note air movement has the potential to facilitate the procedure; the endotracheal tube whistle is such a device.
TECHNIQUE The endotracheal tube whistle is a plastic cylindrical device 2 cm in length and 2 cm in diameter that attaches easily to the 15mm endotracheal tube adapter (Figure 1). The proximal end of the whistle has inner and outer orifices that, depending on the direction of air movement, create sounds of different pitches, producing a biphasic whistling pattern during the inspirationexpiration cycle. To use the whistle, the patient is positioned and prepared for the intubation in standard fashion) The lubricated endotracheal tube is inserted into the nostril and advanced to the posterior nasopharynx. As air flows through the tube, a whistling sound is produced. As the tube approaches the larynx, the whistle becomes louder. The orifice design produces sounds of different pitches; the sounds are higher on inspiration and lower on expiration. When the tube is just above the vocal cords, the physician listens for the higher pitch associated with inspiration, signifying abducted vocal cords; the tube is then advanced into the trachea. If the tube deviates from the airway, immediate diminution or loss of the biphasic whistle sound will indicate the need to withdraw the tube and redirect it. Esophageal intubation results i n complete loss of the whistle sounds or the production of a onepitch whistle from air expelled from the stomach. 2
Figure 1. Beck Airway Airflow Monitor MARK IV endotracheal tube whistle.
46/34 ii
Once the tube has been placed, the whistle is removed, the endotracheal tube balloon is inflated, and the patient is ventilated. Correct tube placement is confirmed by standard methods. We conducted a nine-month prospective study of the use of the whistle during blind nasotracheal intubation with Samaritan AirEvac, Phoenix, Arizona. AirEvac is the primary emergency air service for Maricopa County, and conducts more than 7,000 combined rotor wing and fixed-wing flights each year. The air medical personnel had included the whistle as part of their standard equipment before this study, and all intubators had received an inservice on its use. The air medical personnel were instructed to use the whistle on all blind nasotracheal intubation attempts and then complete a qnestionnaire regarding the use of the whistle (Figure 2).
RESULTS Forty-seven blind nasotracheal intubation attempts were made using the whistle. Thirty-nine of the 47 attempts were successful, and correct endotracheal tube placement was verified by the emergency physician in all but four of the cases. These latter four endotracheal tubes were believed to be Correctly placed by the air medical personnell but there was no recording of ED verification. O f the eight unsuccessful intubations, five were missed because the patients had inadequate spontaneous respirations to allow blind nasotracheal intubation, even with the use of the whistle. One was missed because of a large amount of blood in the pharynx. Two were perceived to be correctly placed but were actually curled up in the posterior pharynx. Every intubator in this study who used the whistle perceived it as being helpful during the intubation and recommended its use. The loud sound of the whistle was perceived to have aided correct endotracheal tube placement in the noisy environment of the helicopter. The Use of the whistle allowed for rapid determination of the near-apneic states of the five patients whose blind nasotracheal intubations were missed due to inadequate respirations. Because the intubator does not need to lean close to the end of the tube to hear the whistle, contact with secretions is lessened. There appeared to be less contact with patients' expectorated sputum, vomitus, and blood when the whistle was in place. On some occasions, the whistle was placed on the endotracheal tube during helicopter flights to help confirm continued correct tube placement. The whistle was found to be easy to use, and although not quantified, users believed that the time required to intubate was decreased with use of the whistle. I~
ANNALS OF EMERGENCY MEBICINE
21:1
JANUARY1992
ENDOTRACHEALTUBE
WHISTLE
Krishel, Jackimczyk & Balazs
There were also some problems with the use of the whistle. Two of the missed attempts were due to the endotracheal tube curling up in the posterior pharynx, resulting in a loud biphasic whistling sound consistent with correct endotracheal tube placement when the tube was actually proximal to the vocal cords. In addition, some of the personnel may have relied on the biphasic whistle sound, without listening for equal breath sounds, to verify endotracheal tube placement. Figure 2.
Questionnaire. PLEASE COMPLETE THE FOLLOWING QUESTIONS: Date:
Flight Number:
1. The blind nasotracheal intubation using the BAAM-MARK IV whistle was successful.
2. The whistle
(
)Yes
(
) No
) helped the intubation. ) hindered the intubation. ) did not affect the intubation.
Please explain:
3. By using the whistle, the time needed to intubate was: Increased (
)
No Change (
)
Decreased (
Please explain:
4. Using the whistle may have placed the patient's health in jeopardy or contributed to a poor clinical outcome. I
) Yes
(
) No
If yes, please explain:
5. Correct endotracheal tube placement was confirmed by the physician in the emergency department. (
) Yes
(
) No
(
) I Don't Know
6. The whistle is easy to use and you would recommend it to other paramedics, (
) Yes
(
) No
Please explain:
DISCUSSION Nasotrachea] intubation offers several advantages over orotracheal intubation in the spontaneously breathing patient. 3 An awake, alert patient may be nasally intubated without inducing paralysis. Use of medication to induce paralysis can lead to increased morbidity in patients with central nervous system trauma, seizures, cerebrovascular accidents, poisoning, and metabolic abnormalities with increased risk of aspiration. 1 A wide variety of spontaneously breathing patients will not tolerate laryngoscopy and would require neuromuscular blockade or sedation to allow orotrachea] intubation. • Such patients include those who are alert; those with trismus secondary to infections, tetanus, or seizures; and those with temporomandibular joint dislocations. Paralyzing such a person to allow orotracheal intubation results in an apneic patient who requires immediate airway intervention. Another large group of patients who may not tolerate laryngoscopy are trauma patients with suspected cervical-spine injury, in whom neck movement may result in neurological damage. Nasotracheal intubation is referred to as "blind" when the tube is passed into the trachea without direct visualization of the vocal cords. The blind approach is feasible because air movement through open vocal cords can be detected as the endotracheal tube is being placed. Requirements for this procedure are spontaneous breathing by the patient to create the air movement and ability of the physician to detect that air movement. The use of a whistle to detect air movement and direction of air flow has the potential to facilitate nasotracheal intubation. The use of the whistle for blind nasotracheal intubation was suggested by Jantzen in 1985. s Since then, two other articles have briefly discussed its u s e . 6 ' 7 This article introduces the endotracheal tube whistle to emergency medicine literature. As the results from the questionnaire revealed, all of the personnel who used the whistle believed it to be helpful during blind nasotracheal intubation and recommended its use. It was easily audible in the helicopter's high-noise environment, allowed rapid detection of near-apneic states of patients, and appeared to lessen contact with patients' secretions. There also was the impression that the use of the whistle decreased the time required to intubate. Although there did not appear to be any complications due to the use of the whistle, this study demonstrated potential problems with relying solely on the whistle sound to verify correct endotracheal tube placement. Because the whistle can make the appropriate sound anywhere past the nasopharynx, the correct whistle sound does not rule out right main stem intubation •
JANUARY 1992
21:1
ANNALS OF EMERGENCY MEDICINE
35/47
I
ENDOTRACHEAL TUBE WHISTLE
Krishel, Jackimczyk & Balazs
and does not guarantee that the tube is in the trachea, distal to the vocal cords. The whistle sound must be correlated to the distance from the nares to the trachea, and correct tube placement must always be verified by standard methods, including chest auscultation and chest radiography. In addition, the whistle may not be useful when a very large amount of blood and secretions is present. This study was designed to demonstrate that the whistle can be used safely and that it may be beneficial to use during blind nasotracheal intubation. We believe the results from our questionnaire demonstrated both of these objectives. Future studies may be required to better define the exact success rate and time required to perform blind nasotracheal intubation using the whistle.
CONCLUSION The endotracheal tube whistle is an adjunct for use during blind nasotracheal intubation. In addition to possibly facilitating tube placement by enhancing the physician's ability to perceive air flow through the tube, it can be used to help confirm correct
48/36
I
position of a previously placed endotracheal tube by the production of a biphasic whistling pattern. Correct tube placement must always be confirmed by standard methods, including chest auscultation and chest radiography. The whistle's use may result in decreased contact with secretions. Both hospital physicians and prehospital care providers may find blind nasotracheal intubation easier to perform with this device. •
REFERENCES 1. Pointer J: Utilizing nasetracheat intubation to full potential. ERReports1982;3:143-148. 2. Beck GP: BeckAirway Aifflow Monitor MARK1[4Directionsfor Use. Donaldsenville, Louisiana, Great Plains Ballistics, Inc. 3. Iserson K: Blind nasetracheal intubatien. Ann EmergMed 1981;10:486. 4. Delaney K: Emergency flexible fibereptic nasetracheal intubatien: A report of 60 cases. Ann EmergMad 1988;17:919-926. 5. Jantzen J: Tracheal intubation - - Blind but net mute. AnesthAnalg 1985;64:651. 6. Cook R, Kurtz M, Cook R, Kurtz M: Air medical use ef the BAAM. Air Mad Trans1989;9:47. 7. Yaron M: Airway management in the resuscitation of trauma patients. Mad Instrum 1988;22:129-134.
Address for reprints: Ken Jackimczyk, MB, FACEP,Departmentof Emergency Medicine, Maricopa Medical Center,2601 East Roosevelt,Phoenix,Arizona85008.
ANNALS OF EMERGENCY MEDICINE
21:1
JANUARY 1992
endotracheal tube whistle
E
ndotracheal Tube Whistle" An Adjunct to
Blind Nasotracheal Intubation
From the Department of Emergency
Scott Krishel, MD*
Medicine, Maricopa Medical
Ken Jackimczyk, MD, FACEP* Kendra Balazs, RN, CCRNt
Center;* and Medical Flight Services, Samaritan AirEvac, t Phoenix, Arizona. Receivedfor publication May 8, 1991. Acceptedfor publication August 13, 1991.
JANUARY 1992 2 1 : 1 ANNALS OF EMERGENOY MEDICINE
To perform blind nasotracheal intubation, the physician feels or listens for air movement through the endotracheal tube to facilitate the tube's passage into the trachea. The tube whistle is a device that attaches to the endotracheal tube adapter and produces whistle sounds of different pitches during inspiration and expiration, enhancing the detection of air movement and possibly allowing for easier intubation. This article describes the use of the whistle and presents information collected from a nine-month prospective study of the endotracheal tube whistle. [Krishel S, Jackimczyk K, Balazs K: Endotracheal tube whistle: An adjunct to blind nasotracheal intubation. Ann Emerg Med January 1992;21:33-36.]
33/45
I
ENDOTRACHEAL TUBE WHISTLE
Krishel, Jackimczyk & Balazs
INTRODUCTION Emergency physicians routinely use orotracheal intubation, nasotracheal intubation, and cricothyrotomy to actively secure airways in the emergency setting. Use of blind nasotracheal intubation has an advantage in that it can be performed on awake, spontaneously breathing patients without inducing paralysis. Blind nasotracheal intubation requires the physician to note air movement while inserting the tube into the trachea. Any device that improves the ability to note air movement has the potential to facilitate the procedure; the endotracheal tube whistle is such a device.
TECHNIQUE The endotracheal tube whistle is a plastic cylindrical device 2 cm in length and 2 cm in diameter that attaches easily to the 15mm endotracheal tube adapter (Figure 1). The proximal end of the whistle has inner and outer orifices that, depending on the direction of air movement, create sounds of different pitches, producing a biphasic whistling pattern during the inspirationexpiration cycle. To use the whistle, the patient is positioned and prepared for the intubation in standard fashion) The lubricated endotracheal tube is inserted into the nostril and advanced to the posterior nasopharynx. As air flows through the tube, a whistling sound is produced. As the tube approaches the larynx, the whistle becomes louder. The orifice design produces sounds of different pitches; the sounds are higher on inspiration and lower on expiration. When the tube is just above the vocal cords, the physician listens for the higher pitch associated with inspiration, signifying abducted vocal cords; the tube is then advanced into the trachea. If the tube deviates from the airway, immediate diminution or loss of the biphasic whistle sound will indicate the need to withdraw the tube and redirect it. Esophageal intubation results i n complete loss of the whistle sounds or the production of a onepitch whistle from air expelled from the stomach. 2
Figure 1. Beck Airway Airflow Monitor MARK IV endotracheal tube whistle.
46/34 ii
Once the tube has been placed, the whistle is removed, the endotracheal tube balloon is inflated, and the patient is ventilated. Correct tube placement is confirmed by standard methods. We conducted a nine-month prospective study of the use of the whistle during blind nasotracheal intubation with Samaritan AirEvac, Phoenix, Arizona. AirEvac is the primary emergency air service for Maricopa County, and conducts more than 7,000 combined rotor wing and fixed-wing flights each year. The air medical personnel had included the whistle as part of their standard equipment before this study, and all intubators had received an inservice on its use. The air medical personnel were instructed to use the whistle on all blind nasotracheal intubation attempts and then complete a qnestionnaire regarding the use of the whistle (Figure 2).
RESULTS Forty-seven blind nasotracheal intubation attempts were made using the whistle. Thirty-nine of the 47 attempts were successful, and correct endotracheal tube placement was verified by the emergency physician in all but four of the cases. These latter four endotracheal tubes were believed to be Correctly placed by the air medical personnell but there was no recording of ED verification. O f the eight unsuccessful intubations, five were missed because the patients had inadequate spontaneous respirations to allow blind nasotracheal intubation, even with the use of the whistle. One was missed because of a large amount of blood in the pharynx. Two were perceived to be correctly placed but were actually curled up in the posterior pharynx. Every intubator in this study who used the whistle perceived it as being helpful during the intubation and recommended its use. The loud sound of the whistle was perceived to have aided correct endotracheal tube placement in the noisy environment of the helicopter. The Use of the whistle allowed for rapid determination of the near-apneic states of the five patients whose blind nasotracheal intubations were missed due to inadequate respirations. Because the intubator does not need to lean close to the end of the tube to hear the whistle, contact with secretions is lessened. There appeared to be less contact with patients' expectorated sputum, vomitus, and blood when the whistle was in place. On some occasions, the whistle was placed on the endotracheal tube during helicopter flights to help confirm continued correct tube placement. The whistle was found to be easy to use, and although not quantified, users believed that the time required to intubate was decreased with use of the whistle. I~
ANNALS OF EMERGENCY MEBICINE
21:1
JANUARY1992
ENDOTRACHEALTUBE
WHISTLE
Krishel, Jackimczyk & Balazs
There were also some problems with the use of the whistle. Two of the missed attempts were due to the endotracheal tube curling up in the posterior pharynx, resulting in a loud biphasic whistling sound consistent with correct endotracheal tube placement when the tube was actually proximal to the vocal cords. In addition, some of the personnel may have relied on the biphasic whistle sound, without listening for equal breath sounds, to verify endotracheal tube placement. Figure 2.
Questionnaire. PLEASE COMPLETE THE FOLLOWING QUESTIONS: Date:
Flight Number:
1. The blind nasotracheal intubation using the BAAM-MARK IV whistle was successful.
2. The whistle
(
)Yes
(
) No
) helped the intubation. ) hindered the intubation. ) did not affect the intubation.
Please explain:
3. By using the whistle, the time needed to intubate was: Increased (
)
No Change (
)
Decreased (
Please explain:
4. Using the whistle may have placed the patient's health in jeopardy or contributed to a poor clinical outcome. I
) Yes
(
) No
If yes, please explain:
5. Correct endotracheal tube placement was confirmed by the physician in the emergency department. (
) Yes
(
) No
(
) I Don't Know
6. The whistle is easy to use and you would recommend it to other paramedics, (
) Yes
(
) No
Please explain:
DISCUSSION Nasotrachea] intubation offers several advantages over orotracheal intubation in the spontaneously breathing patient. 3 An awake, alert patient may be nasally intubated without inducing paralysis. Use of medication to induce paralysis can lead to increased morbidity in patients with central nervous system trauma, seizures, cerebrovascular accidents, poisoning, and metabolic abnormalities with increased risk of aspiration. 1 A wide variety of spontaneously breathing patients will not tolerate laryngoscopy and would require neuromuscular blockade or sedation to allow orotrachea] intubation. • Such patients include those who are alert; those with trismus secondary to infections, tetanus, or seizures; and those with temporomandibular joint dislocations. Paralyzing such a person to allow orotracheal intubation results in an apneic patient who requires immediate airway intervention. Another large group of patients who may not tolerate laryngoscopy are trauma patients with suspected cervical-spine injury, in whom neck movement may result in neurological damage. Nasotracheal intubation is referred to as "blind" when the tube is passed into the trachea without direct visualization of the vocal cords. The blind approach is feasible because air movement through open vocal cords can be detected as the endotracheal tube is being placed. Requirements for this procedure are spontaneous breathing by the patient to create the air movement and ability of the physician to detect that air movement. The use of a whistle to detect air movement and direction of air flow has the potential to facilitate nasotracheal intubation. The use of the whistle for blind nasotracheal intubation was suggested by Jantzen in 1985. s Since then, two other articles have briefly discussed its u s e . 6 ' 7 This article introduces the endotracheal tube whistle to emergency medicine literature. As the results from the questionnaire revealed, all of the personnel who used the whistle believed it to be helpful during blind nasotracheal intubation and recommended its use. It was easily audible in the helicopter's high-noise environment, allowed rapid detection of near-apneic states of patients, and appeared to lessen contact with patients' secretions. There also was the impression that the use of the whistle decreased the time required to intubate. Although there did not appear to be any complications due to the use of the whistle, this study demonstrated potential problems with relying solely on the whistle sound to verify correct endotracheal tube placement. Because the whistle can make the appropriate sound anywhere past the nasopharynx, the correct whistle sound does not rule out right main stem intubation •
JANUARY 1992
21:1
ANNALS OF EMERGENCY MEDICINE
35/47
I
ENDOTRACHEAL TUBE WHISTLE
Krishel, Jackimczyk & Balazs
and does not guarantee that the tube is in the trachea, distal to the vocal cords. The whistle sound must be correlated to the distance from the nares to the trachea, and correct tube placement must always be verified by standard methods, including chest auscultation and chest radiography. In addition, the whistle may not be useful when a very large amount of blood and secretions is present. This study was designed to demonstrate that the whistle can be used safely and that it may be beneficial to use during blind nasotracheal intubation. We believe the results from our questionnaire demonstrated both of these objectives. Future studies may be required to better define the exact success rate and time required to perform blind nasotracheal intubation using the whistle.
CONCLUSION The endotracheal tube whistle is an adjunct for use during blind nasotracheal intubation. In addition to possibly facilitating tube placement by enhancing the physician's ability to perceive air flow through the tube, it can be used to help confirm correct
48/36
I
position of a previously placed endotracheal tube by the production of a biphasic whistling pattern. Correct tube placement must always be confirmed by standard methods, including chest auscultation and chest radiography. The whistle's use may result in decreased contact with secretions. Both hospital physicians and prehospital care providers may find blind nasotracheal intubation easier to perform with this device. •
REFERENCES 1. Pointer J: Utilizing nasetracheat intubation to full potential. ERReports1982;3:143-148. 2. Beck GP: BeckAirway Aifflow Monitor MARK1[4Directionsfor Use. Donaldsenville, Louisiana, Great Plains Ballistics, Inc. 3. Iserson K: Blind nasetracheal intubatien. Ann EmergMed 1981;10:486. 4. Delaney K: Emergency flexible fibereptic nasetracheal intubatien: A report of 60 cases. Ann EmergMad 1988;17:919-926. 5. Jantzen J: Tracheal intubation - - Blind but net mute. AnesthAnalg 1985;64:651. 6. Cook R, Kurtz M, Cook R, Kurtz M: Air medical use ef the BAAM. Air Mad Trans1989;9:47. 7. Yaron M: Airway management in the resuscitation of trauma patients. Mad Instrum 1988;22:129-134.
Address for reprints: Ken Jackimczyk, MB, FACEP,Departmentof Emergency Medicine, Maricopa Medical Center,2601 East Roosevelt,Phoenix,Arizona85008.
ANNALS OF EMERGENCY MEDICINE
21:1
JANUARY 1992
