ORIGINAL CONTRIBUTION nasotracheal intubation
Nasotracheal Intubation Using a Flexible Lighted Stylet Nasotracheal intubation is an essential skill for clinicians involved in the care of acutely ill or injured patients. Unfortunately, it has the dangers and difficulties of any blind technique. Although usually performed in the awake patient, ,nasotracheaI intubation has also been used in the apneic patient. Tdansilluh~ination of the soft tissues of the neck with a lighted stylet has been shown to be a reliable method of orotracheai intubation. The usefulness of a longer, flexible lighted stylet as an aid to nasotracheal intubation in the apneic patient has been examined. Eighty patients, who were paralyzed, apneic, and about to undergo nasotracheal intubation for elective ear, nose, and throat or maxillofacial surgery were randomized to be nasotracheally intubated blindly or with a stylet by an emergency medicine resident or anesthesiologist. Sixty-three percent intubated in the lighted-stylet group and 41% in the blind nasotracheal intubation group were successfully intubated. There were no significant differences in the time needed to intubate or the number of attempts. There were notable differences in the success rates of individual intubators with each tech~ nique. Although not statistically significant, our results suggest a useful role for the lighted stylet in nasotracheal intubation in the apneic patient. [Verdile VP, Chiang J-L, Bedger R, Stewart RD, Kaplan R, Paris PM: Nasotracheal intubation using a flexible lighted stylet. Ann Emerg Med May 1990;19:506-510..
INTRODUCTION Endotracheal intubation is an essential skill for all emergency physicians. Because of the variety of ways in which patients present with airway compromise, it is essential for clinicians to be proficient in several different airway maneuvers. While the most common route of endotracheal tube placement is orotracheal by direct visualization, guiding the tube through the nose can offer significant advantages in selected patients. Success rates of 90% or more have been demonstrated with nasotracheal intubation (NTI) in the emergency patient. 1-3 The NTI technique practiced by most emergency physicians relies on the presence of the sound of air exchange in the oropharynx to guide the endotracheal tube through the glottic opening. Most physicians would, therefore, consider the presence of spontaneous respirations necessary before deciding on this method of intubation. Despite this patient selection, the procedure of NTI as it is presently practiced is essentially a blind technique. There arc several reports of blind NTI in apneic patients about to undergo surgical procedures. 4-6 Reported success rates for blind NTI in these patients are as high as 96%. 4 Although the spontaneously breathing patient is more likely to be chosen for NTI in the emergency department, apnea should not necessarily prevent the use of this technique. Transillumination of the soft tissues of the neck with a lighted stylet has been shown to be a reliable method of orotracheal intubation in both the prehospital setting 7 and the operating room. s-lo The design of a more flexible lighted stylet offers the possibility of using the transillumination method for NTI. The goal of this study was to compare the intubation success rate using the flexible lighted stylet in NTI with that of blind NTI in the apneic
19:5 May 1990
Annals of Emergency Medicine
Vincent P Verdile, MD* Juei-Ling Chiang, MDt Richard Bedger, MD1Pittsburgh, Pennsylvania Ronaid D Stewart, MD¢ Toronto, Ontario Richard Kaplan, MS§ Paul M Paris, MD* Pittsburgh, Pennsylvania From the Division of Emergency Medicine* and Department of Anesthesiology,¢ University of Pittsburgh School of Medicine; Center for Emergency Medicine,§ Pittsburgh, Pennsylvania; and the Departments of Surgery and Anesthesia, Sunnybrook/University of Toronto Medical Centre, Toronto, Ontario, Canada.¢ Received for publication December 21, 1988. Revision received September 25, 1989. Accepted for publication January 8, 1990. Presented at the University Association for Emergency Medicine Annual Meeting in Cincinnati, Ohio, May 1988. Address for reprints: Vincent P Verdile, MD, 230 McKee Place, Suite 500, Pittsburgh, Pennsylvania 15213.
506/39
NASOTRACHEAL INTUBATION Verdile et at
FIGURE 1. Nasal Rae ® endotracheal tube. FIGURE 2. Flexible nasotracheal lighted stylet.
patient. The study was designed to d e t e r m i n e w h e t h e r the use of a lighted stylet in NTI would facilitate endotracheal tube placement so that this technique might be expanded to include the apneic patient who can not be intubated by or has failed conventional intubation methods. It is the first such study examining the use of the lighted stylet in NTI in the apneic patient.
METHODS This randomized, prospective study was approved by the Institutional Review Board for-Biomedical Research of the University of Pittsburgh. The s t u d y p o p u l a t i o n included 80 patients, who were American Society of Anesthesiology (ASA) classes I through III and between the ages of 14 and 77 years. These patients were scheduled to undergo NTI for elective ear, nose, and throat or m a x i l l o f a c i a l surgery. Using a standard r a n d o m i z a t i o n chart, patients were randomized into either the lighted-stylet N T I group or the blind NTI group before intubation. All patients were paralyzed using a standard induction technique. The Nasal Rae ® endotracheal tube (Mallinckrodt Inc, Glens Falls, New York) was used for all intubations (Figure 1). The l i g h t e d - s t y l e t i n t u b a t i o n s were performed using a 33-cm TubeStat s NTI stylet (Concept Inc, Clearwater, Florida) (Figure 2). The lighted styler was placed inside of the Nasal Rae ® endotracheal tube before any intubation attempts. Two centimeters were cut from the proximal end of the endotracheal tube to allow the bulb at the end of the lighted stylet to reach the most distal aspect of the endotracheal tube without extending beyond the eyelet. In both groups of patients, the endotracheal tube was lubricated with a jelly lubricant before any intubation attempts. The intubations were performed by a PGY-III emergency medicine resident or one of two attending anesthesiologists. Each intubator was experienced in airway maneuvers and was oriented to the lighted stylet before beginning the study. Each patient 40/507
was intubated by only one intubator using one method. Each intubator was limited to three intubation att e m p t s to m i n i m i z e the r i s k of iatrogenic injury. After three unsuccessful attempts, patients were intubated with direct visualization using a laryngoscope and Magill forceps. Each patient included in the study had an a u t o m a t i c blood pressurerecording device (Dinamap ®, Critikon Corp, Tampa, Florida), a standard oscilloscopic monitor to monitor heart rate and rhythm, and a digital pulse oximetry monitor applied Annals of Emergency Medicine
before induction. An independent, nonphysician observer was responsible for recording the duration of each intubation attempt, dysrhythmias, vital sign changes, or oxygen desaturation. A 90-second time limit was allowed for each intubation attempt, and the p a t i e n t s were reoxygenated w i t h 100% oxygen between attempts. Endotracheal tube placement was assessed after each att e m p t by auscultation of the chest and epigastrium, checking oxygen saturation, and noting compliance with ventilation. 19:5 May 1990
FIGURE 3. Lighted stylet compared
with blind nasotracheal intubations.
100
FIGURE 4. Lighted stylet compared
with blind intubation success rate by intubator.
80
:i:ii:!:i~!i!i:ii:~:i!i!i:i!~!~!i!~!:!~!
The patients in the lighted-stylet group had the tube-stylet combination inserted through the nose, with the head in the neutral position. After advancing the tube-stylet combination into the hypopharynx, the operating room lights were dimmed. Indirect lighting from the hallways and radiographic viewboxes allowed for sufficient i l l u m i n a t i o n so that patients could be observed during the intubation. W h e n the characteristic bright midline glow of light through the soft tissues of the anterior neck was seen, the tube-stylet combination was advanced through the glottic opening, and the Nasal Rae ® tube was advanced off the stylet and into the trachea. T h e EPISTAT® c o m p u t e r software package was used for data analyses. x 2 analysis was applied for the statistical evaluation of the success rates between blind and lighted-stylet patient groups. The Wilcoxon rank-sum test was used for comparing the time required for successful intubation. P .05 was accepted as denoting statistical significance, and the calculated p-error was 0.8.
i......... !i!i:Z'Z!ZZ i!ilili:ii................ !i:ilili:!i!i!:!:!:!:!:!~!:~ Z.Z./
RESULTS
60 < -5 40 O O
iiiiiiiiiiiiiiiiiiii iiiiiiiiiiil iiiiiiiiii!iiiiii!ii ii!i
o') 20
•
[]
Lighted stylet
[]
Blind
3
100 ~ii!iiilii~iii~i¸iliiii!ilil
:! : :!:!:! i:i: i:i!:!: ~!~!i!ii:i:ii!ili
80
60 rr
8
i:iii Z I .........
40
09
C Z ............ :
. . . . . . Z?ZIZZI.I,?,I,TL
20
•
i:iiii:i:ii!i!:!!:!~!~!~!:~:
i!iiii!i!iiiii!i!ii!i'i i i!i!i i !!ii:i •::: ::::::
0
i~i~~ii~~i iii'~i!ii!i!ii!i:!i!i!iii!
iiiiiiiiiiiiiiiiiiiiiiiiiiiii!iiiiiii A2
A1
EM*
INTUBATOR []
Lighted stylet
[]
Blind
*EM, emergency medicine resident; A1, first anesthesiologist; A2, second anesthesiologist.
Patients intubated w i t h the blind nasotracheal technique were placed in the neutral position after induction, and every attempt was made to avoid gross manipulation of the head and neck during intubation. The Na19:5 May 1990
The two patient groups were similar in respect to ASA status, age, and gender. Of the 80 patients, 42 (53%) were intubated successfully. In the lighted-stylet group, 26 of 41 (63%) were successfully intubated compared with 16 of 39 (41%) in the blind group (Figure 3). This difference was n o t s t a t i s t i c a l l y s i g n i f i c a n t (P = .075). Patients in the lighted-stylet group required an average of 1.47 attempts for NTI compared with an average of 1.55 attempts for those in the blind N T I group. The mean time for successful i n t u b a t i o n in t h e lightedstylet group for all three intubators was 63.7 + 51.2 seconds. Similarly, the mean time for successful intubation in the blind group for all intubators was 45.8 _+ 24 seconds. This difference was not statistically significant (P > .05). The emergency medicine resident
sal Rae ® endotracheal tube, without a stylet, was passed through the nose in the standard fashion, w i t h chinlifting, Sellick's maneuver, or lateral displacement of the larynx to facilitate intratracheal placement. Annals of Emergency Medicine
508/41
NASOTRACHEAL INTUBATION Verdile et al
successfully intubated seven of 13 patients (54%} in the lighted-stylet group and three of ten patients (30%) in the blind group. Experience proved beneficial for the emergency medicine resident as six of seven lightedstylet intubations (86%1 occurred in the latter half of the study. T h e first a n e s t h e s i o l o g i s t successfully intubated 16 of 19 patients (84%) in the lighted-styler group and five of 13 (38%) in the blind group. The second anesthesiologist was less successful with the lighted stylet, intubating only three of nine patients (33%) in this group and eight of 16 patients (50%) in the blind group (Figure 4). Neither anesthesiologist demonstrated a similar trend of improved success rate in the latter half of the study. None of the patients was followed postoperatively. T h e only p a t i e n t complication noted was that of epistaxis in 18 patients (23%). DISCUSSION The impetus for this study was the successful N T I guided by lighted stylet in a trauma patient with maxillofacial injuries who was hypoventilating and could not be intubated by direct laryngoscopy. 1~ The lighted styler facilitated intratracheal placement of the endotracheal tube in this difficult intubation because of the visual clues gathered from the transi l l u m i n a t i o n of the anterior neck. Although there are m a n y descriptions and reports of aids to NTI, including rigid stylets, tongue extrusion techniques, and fiberoptic laryngoscopy, l~-17 it was hoped that the flexible, lighted stylet would offer a quick, inexpensive, and easily operated device t h a t w o u l d f a c i l i t a t e NTI. It would have been clinically relevant to turn the current procedure of b l i n d N T I in t h e s p o n t a n e o u s l y breathing patient into a guided procedure with the t r a n s i l l u m i n a t i o n method. In addition, it would have been useful to be able to expand the use of NTI to the hypoventilating or apneic patient who has failed conventional intubation methods or in w h o m NTI offers some distinct advantage. Lighted-stylet N T I could conceivably have further ensured the ability to intubate a patient after the administration of a neuromuscularblocking agent. There are several reports of successful NTI in apneic pa42/509
tients with success rates as high as 91% and 96%.4-6 Although a trend of improved success with lighted-stylet NTI was demonstrated, the relatively low success rate does not lend itself to recommending the routine use of the lighted stylet for all N T I and for NTI in the apneic patient in particular. N T I has the dangers and diffic u l t i e s of a n y b l i n d t e c h n i q u e . Esophageal placement of the endotracheal tube can delay definitive airway control and may be lethal if unrecognized. ~s-~l By using the transillumination method, the technique of lighted-stylet NTI might help prevent unrecognized esophageal intubations. Although we did not examine this specifically, it was our observation that endotracheal tubes placed in the esophagus with the blind technique could be suspected only after auscultation of the chest and epigastrium. The esophageal intubations in the lighted-stylet group were accompanied by the physical findings of either a diminished glow of light or a c o m p l e t e a b s e n c e of l i g h t through the soft tissues of the anterior neck. This has been observed in other reports that used the transillumination method.7, 22-z4 It would be a clear advantage to using the lighted stylet in NTI if esophageal intubations could be avoided or at least recognized sooner. This might be particularly advantageous for the patients urgently intubated through the nasotracheal route in the relatively uncontrolled setting of the ED or prehospital care area. 2°,2s,26 Our success rates for NTI in the apneic patient are lower than those achieved with awake patients, which have been reported as high as 96% in patients about to undergo surgery a7 and as high as 92% in ED patients.a, 3 Furthermore, our success rates for NTI are also lower than those of NTI in apneic patients, which have been reported to be as high as 96% .4-6 Several factors may have contributed to our limited success. First, the Nasal Rae ® e n d o t r a c h e a l t u b e does n o t have a directional tip or any other mechanism to manipulate the distal tip once it is in the oropharynx. A stylet or an endotracheal tube with a directional tip would have possibly enhanced our success rate in the apneic patient by enabling the light source at the end of the tube-stylet to be moved anteriorly and closer to the Annals of Emergency Medicine
glottic opening. The unusual configuration of the proximal end of the Nasal Rae ® tube made maneuvering awkward in both patient groups (Figure 1). Unfortunately, this particular endotracheal tube was the tube of choice by the maxillofacial surgeons. A second factor that limited our success rate was the fact that our study group included many patients with head and neck malignancies or p o s t - t r a u m a t i c d e f o r m i t i e s of the mouth or midface. The normal anatomic landmarks were often missing or disfigured, making any type of intubation potentially difficult. Lastly, the apneic patient is not the usual patient selected to undergo the procedure of NTI. Without the sound of air exchange and the evidence for c o n d e n s a t i o n in the e n d o t r a c h e a l tube as it advances toward the glottic opening, The passage of the endotracheal tube through the nasal route is truly blind. By selecting the apneic patient for this study, the potentially worst case scenario was simulated, that of an ED patient who after receiving a n e u r o m u s c u l a r - b l o c k i n g agent could not be intubated by conventional techniques short of a surgical airway. The mean times and standard deviations for s u c c e s s f u l N T I in the lighted-stylet group (63.7 +- 51.2 seconds) and in the blind N T I group (48.8 + 24 s e c o n d s ) s e e m inordinately long. The awkward configuration of the Nasal Rae ® tube, the patient's anatomic anomalies, and the fact that the patients were apneic all contributed to the prolonged times for successful intubation. If our NTI intubation times are compared with the NTI intubation times in studies with apneic patients, however, there does not appear to be such a gross discrepancy. Maltby et al reported a time for successful NTI between 70 and 180 seconds for the apneic patient; s our times for successful intubation in the apneic patient were comparable. Furthermore, our times for successful NTI in the apneic patient were comparable to the time for successful N T I in awake p a t i e n t s (mean time, 119.7 seconds) as reported by Fox et al. 9 It is difficult to explain why the second anesthesiologist seemed less proficient with the lighted stylet and had noticeably less success with it than the other two intubators. All three intubators were similarly inex19:5 May 1990
perienced in the use of the lighted stylet at the beginning of the study. Furthermore, the limited success of the second anesthesiologist was in contrast to that of the other, who had an 84% success rate in the lightedstylet group. CONCLUSION This study represents the first effort to demonstrate the use of a flexible, lighted stylet in NTI in the apneic patient. We have shown that blind NTI with the Nasal Rae ® endotracheal tube in apneic patients appears to have a success rate significantly lower than that of awake NTI and lower than the reported success rates for NTI in the apneic patient. A l t h o u g h our s u c c e s s rates for lighted-styler NTI in apneic patents are not as high as those achieved in awake NTI, our data suggest a useful r o l e for t h e t r a n s i l l u m i n a t i o n method. We were not able to demonstrate with statistical significance that lighted-stylet NTI was better than blind NTI in the apneic patient and, therefore, cannot recommend the use of the lighted stylet in the apneic patient for NTI. The early recognition or prevention of esophageal intubations may be the most important role for the lighted stylet in NTI; this warrants investigation. Future studies should use a directional-tip endotracheal tube and a patient population more characteristic of the general ED population requiring NTI. It would be particularly useful to study patients who are breathing spontaneously.
19:5 May 1990
REFERENCES 1. Tintinalli JE, Claffey J: Complications of nasotracheal intubation. Ann Emerg Med 1981; 10:142-144.
sotracheal intubation (letter). Anesth Analg 1987;66:283-284. 14. Davies JAH: Blind nasal intubation with propanidid. Br J Anaesth 1972;44:528-530.
2. Danzl DF, Thomas DM: Nasotracheal intubation in the emergency department. Grit Care Med 1980;8:677-682.
15. Adams AL, Cane RD, Shapiro BA: Tongue extrusion as an aid to blind nasal intubation. Crit Care Med 1982;10:335-336.
3. Iserson KV: Blind nasotracheal intubation. Ann Emerg Med 1981;10:468-471.
16. Berry FA: The use of a stylet in blind nasotracheal intubation. Anesthesiology 1984; 61:469-471.
4. Fassolt A: Blind nasal tracheal intubation in the muscle relaxed patient. Anaesthesist 1986; 35:505-508. 5. Mahby JR, Cassidy M, Nanji GM: Blind nasotracheal intubation using succinylcholine. Anesthesiology 1988;69:946-948 6. Gross JB, Hartigan ML, Schaffer DW: A suitable substitute for 4% cocaine before blind nasotracheal intubation: 3% lidocaine-0.25% p h e n y l e p h r i n e nasal spray. A n e s t h Analg 1984;63:915-918. 7. Vollmer TP, Stewart RD, Paris PM, et ah Use of a lighted styler for guided orotracheal intubation in the prehospita] setting. Ann Emerg Med 1985;14:324-328. 8. Ellis DG, Jakymec A, Kaplan RM, et ah Guided orotracheal intuhation in the operating room using a lighted stylet: A comparison with direct laryngoscopic technique. Anesthesiology 1986;64:823-826. 9. Fox DJ, Castro T, Rastrelli AJ: Comparison of intubation techniques in the awake patient: The flexi-lum surgical light (lightwand) versus blind nasal approach. Anesthesiology 1987; 66:69-71. 10. Ellis DG, Stewart RD, Kaplan RM, et ah Success rates of blind orotracheal intubation using a transillumination technique with a lighted stylet. Ann Emerg Med 1986;15:138-142. 11. Verdile VP, Heller MB, Paris PM, et ah Nasotracheal intubation in traumatic craniofacial dislocation: Use of the lighted stylet. A m J Emerg Med 1988;1:39-41. 12. Mishkel L, Wang JF, Gutierrez F, et ah Nasotracheal intubation by fiheroptic laryngoscope. South Med J 1981;74:1407-1409. 13. Donenfeld RF: A technique to aid blind na-
Annals of Emergency Medicine
17. Sleeman KW: An introducer to facilitate nasotracheal intubation. Anaesth Intens Care 1979;7:381-382. 18. Birmingham PK, Cheney FW, Ward RJ: Esophageal intubation: A review of detection techniques. Anesth Analg 1986;65:886-891. 19. Utting JE, Gray TC, Shelley FC: Human misadventure in anaesthesia. Can Anaesth Soc J 1979;26:472-478. 20. Stewart RD, Paris PM, Winter PM, et al: Field endotracheal intubation by paramedical personnel: Success rates and complications. Chest 1984~85:341-345. 21. Keenan RL, Boyan CPP: Cardiac arrest due to anesthesia: A study of incidence and causes. JAMA 1985;253:2372-2377. 22. Hammer M, Garry B: Transillumination of the trachea with flexilum (letter). Anesth Analg 1985;64:91-92. 23. Raybum RL: "Light wand" intubation (letter). Anaesthesia 1979;34:677-678. 24. Stewart RD, LaRosse A, Stoy WA, et ah Use of a lighted stylet to confirm correct endotracheal tube placement. Chest 1987;92: 900-903. 25. Stewart RD, Paris PM: Signs of endotracheal intubation in a field setting (letter). Ann Emerg Med 1985;14:t29-130. 26. Abarbanell NR: Esophageal placement of an endotracheal tube by paramedics: Problems with current management. A m J Emerg Med 1988;6:178-179. 27. Gold MI, Buechel DR: A method of blind nasal intubation for the conscious patient. Anesth Analg 1960;39:257-263.
510/43
Nasotracheal Intubation Using a Flexible Lighted Stylet Nasotracheal intubation is an essential skill for clinicians involved in the care of acutely ill or injured patients. Unfortunately, it has the dangers and difficulties of any blind technique. Although usually performed in the awake patient, ,nasotracheaI intubation has also been used in the apneic patient. Tdansilluh~ination of the soft tissues of the neck with a lighted stylet has been shown to be a reliable method of orotracheai intubation. The usefulness of a longer, flexible lighted stylet as an aid to nasotracheal intubation in the apneic patient has been examined. Eighty patients, who were paralyzed, apneic, and about to undergo nasotracheal intubation for elective ear, nose, and throat or maxillofacial surgery were randomized to be nasotracheally intubated blindly or with a stylet by an emergency medicine resident or anesthesiologist. Sixty-three percent intubated in the lighted-stylet group and 41% in the blind nasotracheal intubation group were successfully intubated. There were no significant differences in the time needed to intubate or the number of attempts. There were notable differences in the success rates of individual intubators with each tech~ nique. Although not statistically significant, our results suggest a useful role for the lighted stylet in nasotracheal intubation in the apneic patient. [Verdile VP, Chiang J-L, Bedger R, Stewart RD, Kaplan R, Paris PM: Nasotracheal intubation using a flexible lighted stylet. Ann Emerg Med May 1990;19:506-510..
INTRODUCTION Endotracheal intubation is an essential skill for all emergency physicians. Because of the variety of ways in which patients present with airway compromise, it is essential for clinicians to be proficient in several different airway maneuvers. While the most common route of endotracheal tube placement is orotracheal by direct visualization, guiding the tube through the nose can offer significant advantages in selected patients. Success rates of 90% or more have been demonstrated with nasotracheal intubation (NTI) in the emergency patient. 1-3 The NTI technique practiced by most emergency physicians relies on the presence of the sound of air exchange in the oropharynx to guide the endotracheal tube through the glottic opening. Most physicians would, therefore, consider the presence of spontaneous respirations necessary before deciding on this method of intubation. Despite this patient selection, the procedure of NTI as it is presently practiced is essentially a blind technique. There arc several reports of blind NTI in apneic patients about to undergo surgical procedures. 4-6 Reported success rates for blind NTI in these patients are as high as 96%. 4 Although the spontaneously breathing patient is more likely to be chosen for NTI in the emergency department, apnea should not necessarily prevent the use of this technique. Transillumination of the soft tissues of the neck with a lighted stylet has been shown to be a reliable method of orotracheal intubation in both the prehospital setting 7 and the operating room. s-lo The design of a more flexible lighted stylet offers the possibility of using the transillumination method for NTI. The goal of this study was to compare the intubation success rate using the flexible lighted stylet in NTI with that of blind NTI in the apneic
19:5 May 1990
Annals of Emergency Medicine
Vincent P Verdile, MD* Juei-Ling Chiang, MDt Richard Bedger, MD1Pittsburgh, Pennsylvania Ronaid D Stewart, MD¢ Toronto, Ontario Richard Kaplan, MS§ Paul M Paris, MD* Pittsburgh, Pennsylvania From the Division of Emergency Medicine* and Department of Anesthesiology,¢ University of Pittsburgh School of Medicine; Center for Emergency Medicine,§ Pittsburgh, Pennsylvania; and the Departments of Surgery and Anesthesia, Sunnybrook/University of Toronto Medical Centre, Toronto, Ontario, Canada.¢ Received for publication December 21, 1988. Revision received September 25, 1989. Accepted for publication January 8, 1990. Presented at the University Association for Emergency Medicine Annual Meeting in Cincinnati, Ohio, May 1988. Address for reprints: Vincent P Verdile, MD, 230 McKee Place, Suite 500, Pittsburgh, Pennsylvania 15213.
506/39
NASOTRACHEAL INTUBATION Verdile et at
FIGURE 1. Nasal Rae ® endotracheal tube. FIGURE 2. Flexible nasotracheal lighted stylet.
patient. The study was designed to d e t e r m i n e w h e t h e r the use of a lighted stylet in NTI would facilitate endotracheal tube placement so that this technique might be expanded to include the apneic patient who can not be intubated by or has failed conventional intubation methods. It is the first such study examining the use of the lighted stylet in NTI in the apneic patient.
METHODS This randomized, prospective study was approved by the Institutional Review Board for-Biomedical Research of the University of Pittsburgh. The s t u d y p o p u l a t i o n included 80 patients, who were American Society of Anesthesiology (ASA) classes I through III and between the ages of 14 and 77 years. These patients were scheduled to undergo NTI for elective ear, nose, and throat or m a x i l l o f a c i a l surgery. Using a standard r a n d o m i z a t i o n chart, patients were randomized into either the lighted-stylet N T I group or the blind NTI group before intubation. All patients were paralyzed using a standard induction technique. The Nasal Rae ® endotracheal tube (Mallinckrodt Inc, Glens Falls, New York) was used for all intubations (Figure 1). The l i g h t e d - s t y l e t i n t u b a t i o n s were performed using a 33-cm TubeStat s NTI stylet (Concept Inc, Clearwater, Florida) (Figure 2). The lighted styler was placed inside of the Nasal Rae ® endotracheal tube before any intubation attempts. Two centimeters were cut from the proximal end of the endotracheal tube to allow the bulb at the end of the lighted stylet to reach the most distal aspect of the endotracheal tube without extending beyond the eyelet. In both groups of patients, the endotracheal tube was lubricated with a jelly lubricant before any intubation attempts. The intubations were performed by a PGY-III emergency medicine resident or one of two attending anesthesiologists. Each intubator was experienced in airway maneuvers and was oriented to the lighted stylet before beginning the study. Each patient 40/507
was intubated by only one intubator using one method. Each intubator was limited to three intubation att e m p t s to m i n i m i z e the r i s k of iatrogenic injury. After three unsuccessful attempts, patients were intubated with direct visualization using a laryngoscope and Magill forceps. Each patient included in the study had an a u t o m a t i c blood pressurerecording device (Dinamap ®, Critikon Corp, Tampa, Florida), a standard oscilloscopic monitor to monitor heart rate and rhythm, and a digital pulse oximetry monitor applied Annals of Emergency Medicine
before induction. An independent, nonphysician observer was responsible for recording the duration of each intubation attempt, dysrhythmias, vital sign changes, or oxygen desaturation. A 90-second time limit was allowed for each intubation attempt, and the p a t i e n t s were reoxygenated w i t h 100% oxygen between attempts. Endotracheal tube placement was assessed after each att e m p t by auscultation of the chest and epigastrium, checking oxygen saturation, and noting compliance with ventilation. 19:5 May 1990
FIGURE 3. Lighted stylet compared
with blind nasotracheal intubations.
100
FIGURE 4. Lighted stylet compared
with blind intubation success rate by intubator.
80
:i:ii:!:i~!i!i:ii:~:i!i!i:i!~!~!i!~!:!~!
The patients in the lighted-stylet group had the tube-stylet combination inserted through the nose, with the head in the neutral position. After advancing the tube-stylet combination into the hypopharynx, the operating room lights were dimmed. Indirect lighting from the hallways and radiographic viewboxes allowed for sufficient i l l u m i n a t i o n so that patients could be observed during the intubation. W h e n the characteristic bright midline glow of light through the soft tissues of the anterior neck was seen, the tube-stylet combination was advanced through the glottic opening, and the Nasal Rae ® tube was advanced off the stylet and into the trachea. T h e EPISTAT® c o m p u t e r software package was used for data analyses. x 2 analysis was applied for the statistical evaluation of the success rates between blind and lighted-stylet patient groups. The Wilcoxon rank-sum test was used for comparing the time required for successful intubation. P .05 was accepted as denoting statistical significance, and the calculated p-error was 0.8.
i......... !i!i:Z'Z!ZZ i!ilili:ii................ !i:ilili:!i!i!:!:!:!:!:!~!:~ Z.Z./
RESULTS
60 < -5 40 O O
iiiiiiiiiiiiiiiiiiii iiiiiiiiiiil iiiiiiiiii!iiiiii!ii ii!i
o') 20
•
[]
Lighted stylet
[]
Blind
3
100 ~ii!iiilii~iii~i¸iliiii!ilil
:! : :!:!:! i:i: i:i!:!: ~!~!i!ii:i:ii!ili
80
60 rr
8
i:iii Z I .........
40
09
C Z ............ :
. . . . . . Z?ZIZZI.I,?,I,TL
20
•
i:iiii:i:ii!i!:!!:!~!~!~!:~:
i!iiii!i!iiiii!i!ii!i'i i i!i!i i !!ii:i •::: ::::::
0
i~i~~ii~~i iii'~i!ii!i!ii!i:!i!i!iii!
iiiiiiiiiiiiiiiiiiiiiiiiiiiii!iiiiiii A2
A1
EM*
INTUBATOR []
Lighted stylet
[]
Blind
*EM, emergency medicine resident; A1, first anesthesiologist; A2, second anesthesiologist.
Patients intubated w i t h the blind nasotracheal technique were placed in the neutral position after induction, and every attempt was made to avoid gross manipulation of the head and neck during intubation. The Na19:5 May 1990
The two patient groups were similar in respect to ASA status, age, and gender. Of the 80 patients, 42 (53%) were intubated successfully. In the lighted-stylet group, 26 of 41 (63%) were successfully intubated compared with 16 of 39 (41%) in the blind group (Figure 3). This difference was n o t s t a t i s t i c a l l y s i g n i f i c a n t (P = .075). Patients in the lighted-stylet group required an average of 1.47 attempts for NTI compared with an average of 1.55 attempts for those in the blind N T I group. The mean time for successful i n t u b a t i o n in t h e lightedstylet group for all three intubators was 63.7 + 51.2 seconds. Similarly, the mean time for successful intubation in the blind group for all intubators was 45.8 _+ 24 seconds. This difference was not statistically significant (P > .05). The emergency medicine resident
sal Rae ® endotracheal tube, without a stylet, was passed through the nose in the standard fashion, w i t h chinlifting, Sellick's maneuver, or lateral displacement of the larynx to facilitate intratracheal placement. Annals of Emergency Medicine
508/41
NASOTRACHEAL INTUBATION Verdile et al
successfully intubated seven of 13 patients (54%} in the lighted-stylet group and three of ten patients (30%) in the blind group. Experience proved beneficial for the emergency medicine resident as six of seven lightedstylet intubations (86%1 occurred in the latter half of the study. T h e first a n e s t h e s i o l o g i s t successfully intubated 16 of 19 patients (84%) in the lighted-styler group and five of 13 (38%) in the blind group. The second anesthesiologist was less successful with the lighted stylet, intubating only three of nine patients (33%) in this group and eight of 16 patients (50%) in the blind group (Figure 4). Neither anesthesiologist demonstrated a similar trend of improved success rate in the latter half of the study. None of the patients was followed postoperatively. T h e only p a t i e n t complication noted was that of epistaxis in 18 patients (23%). DISCUSSION The impetus for this study was the successful N T I guided by lighted stylet in a trauma patient with maxillofacial injuries who was hypoventilating and could not be intubated by direct laryngoscopy. 1~ The lighted styler facilitated intratracheal placement of the endotracheal tube in this difficult intubation because of the visual clues gathered from the transi l l u m i n a t i o n of the anterior neck. Although there are m a n y descriptions and reports of aids to NTI, including rigid stylets, tongue extrusion techniques, and fiberoptic laryngoscopy, l~-17 it was hoped that the flexible, lighted stylet would offer a quick, inexpensive, and easily operated device t h a t w o u l d f a c i l i t a t e NTI. It would have been clinically relevant to turn the current procedure of b l i n d N T I in t h e s p o n t a n e o u s l y breathing patient into a guided procedure with the t r a n s i l l u m i n a t i o n method. In addition, it would have been useful to be able to expand the use of NTI to the hypoventilating or apneic patient who has failed conventional intubation methods or in w h o m NTI offers some distinct advantage. Lighted-stylet N T I could conceivably have further ensured the ability to intubate a patient after the administration of a neuromuscularblocking agent. There are several reports of successful NTI in apneic pa42/509
tients with success rates as high as 91% and 96%.4-6 Although a trend of improved success with lighted-stylet NTI was demonstrated, the relatively low success rate does not lend itself to recommending the routine use of the lighted stylet for all N T I and for NTI in the apneic patient in particular. N T I has the dangers and diffic u l t i e s of a n y b l i n d t e c h n i q u e . Esophageal placement of the endotracheal tube can delay definitive airway control and may be lethal if unrecognized. ~s-~l By using the transillumination method, the technique of lighted-stylet NTI might help prevent unrecognized esophageal intubations. Although we did not examine this specifically, it was our observation that endotracheal tubes placed in the esophagus with the blind technique could be suspected only after auscultation of the chest and epigastrium. The esophageal intubations in the lighted-stylet group were accompanied by the physical findings of either a diminished glow of light or a c o m p l e t e a b s e n c e of l i g h t through the soft tissues of the anterior neck. This has been observed in other reports that used the transillumination method.7, 22-z4 It would be a clear advantage to using the lighted stylet in NTI if esophageal intubations could be avoided or at least recognized sooner. This might be particularly advantageous for the patients urgently intubated through the nasotracheal route in the relatively uncontrolled setting of the ED or prehospital care area. 2°,2s,26 Our success rates for NTI in the apneic patient are lower than those achieved with awake patients, which have been reported as high as 96% in patients about to undergo surgery a7 and as high as 92% in ED patients.a, 3 Furthermore, our success rates for NTI are also lower than those of NTI in apneic patients, which have been reported to be as high as 96% .4-6 Several factors may have contributed to our limited success. First, the Nasal Rae ® e n d o t r a c h e a l t u b e does n o t have a directional tip or any other mechanism to manipulate the distal tip once it is in the oropharynx. A stylet or an endotracheal tube with a directional tip would have possibly enhanced our success rate in the apneic patient by enabling the light source at the end of the tube-stylet to be moved anteriorly and closer to the Annals of Emergency Medicine
glottic opening. The unusual configuration of the proximal end of the Nasal Rae ® tube made maneuvering awkward in both patient groups (Figure 1). Unfortunately, this particular endotracheal tube was the tube of choice by the maxillofacial surgeons. A second factor that limited our success rate was the fact that our study group included many patients with head and neck malignancies or p o s t - t r a u m a t i c d e f o r m i t i e s of the mouth or midface. The normal anatomic landmarks were often missing or disfigured, making any type of intubation potentially difficult. Lastly, the apneic patient is not the usual patient selected to undergo the procedure of NTI. Without the sound of air exchange and the evidence for c o n d e n s a t i o n in the e n d o t r a c h e a l tube as it advances toward the glottic opening, The passage of the endotracheal tube through the nasal route is truly blind. By selecting the apneic patient for this study, the potentially worst case scenario was simulated, that of an ED patient who after receiving a n e u r o m u s c u l a r - b l o c k i n g agent could not be intubated by conventional techniques short of a surgical airway. The mean times and standard deviations for s u c c e s s f u l N T I in the lighted-stylet group (63.7 +- 51.2 seconds) and in the blind N T I group (48.8 + 24 s e c o n d s ) s e e m inordinately long. The awkward configuration of the Nasal Rae ® tube, the patient's anatomic anomalies, and the fact that the patients were apneic all contributed to the prolonged times for successful intubation. If our NTI intubation times are compared with the NTI intubation times in studies with apneic patients, however, there does not appear to be such a gross discrepancy. Maltby et al reported a time for successful NTI between 70 and 180 seconds for the apneic patient; s our times for successful intubation in the apneic patient were comparable. Furthermore, our times for successful NTI in the apneic patient were comparable to the time for successful N T I in awake p a t i e n t s (mean time, 119.7 seconds) as reported by Fox et al. 9 It is difficult to explain why the second anesthesiologist seemed less proficient with the lighted stylet and had noticeably less success with it than the other two intubators. All three intubators were similarly inex19:5 May 1990
perienced in the use of the lighted stylet at the beginning of the study. Furthermore, the limited success of the second anesthesiologist was in contrast to that of the other, who had an 84% success rate in the lightedstylet group. CONCLUSION This study represents the first effort to demonstrate the use of a flexible, lighted stylet in NTI in the apneic patient. We have shown that blind NTI with the Nasal Rae ® endotracheal tube in apneic patients appears to have a success rate significantly lower than that of awake NTI and lower than the reported success rates for NTI in the apneic patient. A l t h o u g h our s u c c e s s rates for lighted-styler NTI in apneic patents are not as high as those achieved in awake NTI, our data suggest a useful r o l e for t h e t r a n s i l l u m i n a t i o n method. We were not able to demonstrate with statistical significance that lighted-stylet NTI was better than blind NTI in the apneic patient and, therefore, cannot recommend the use of the lighted stylet in the apneic patient for NTI. The early recognition or prevention of esophageal intubations may be the most important role for the lighted stylet in NTI; this warrants investigation. Future studies should use a directional-tip endotracheal tube and a patient population more characteristic of the general ED population requiring NTI. It would be particularly useful to study patients who are breathing spontaneously.
19:5 May 1990
REFERENCES 1. Tintinalli JE, Claffey J: Complications of nasotracheal intubation. Ann Emerg Med 1981; 10:142-144.
sotracheal intubation (letter). Anesth Analg 1987;66:283-284. 14. Davies JAH: Blind nasal intubation with propanidid. Br J Anaesth 1972;44:528-530.
2. Danzl DF, Thomas DM: Nasotracheal intubation in the emergency department. Grit Care Med 1980;8:677-682.
15. Adams AL, Cane RD, Shapiro BA: Tongue extrusion as an aid to blind nasal intubation. Crit Care Med 1982;10:335-336.
3. Iserson KV: Blind nasotracheal intubation. Ann Emerg Med 1981;10:468-471.
16. Berry FA: The use of a stylet in blind nasotracheal intubation. Anesthesiology 1984; 61:469-471.
4. Fassolt A: Blind nasal tracheal intubation in the muscle relaxed patient. Anaesthesist 1986; 35:505-508. 5. Mahby JR, Cassidy M, Nanji GM: Blind nasotracheal intubation using succinylcholine. Anesthesiology 1988;69:946-948 6. Gross JB, Hartigan ML, Schaffer DW: A suitable substitute for 4% cocaine before blind nasotracheal intubation: 3% lidocaine-0.25% p h e n y l e p h r i n e nasal spray. A n e s t h Analg 1984;63:915-918. 7. Vollmer TP, Stewart RD, Paris PM, et ah Use of a lighted styler for guided orotracheal intubation in the prehospita] setting. Ann Emerg Med 1985;14:324-328. 8. Ellis DG, Jakymec A, Kaplan RM, et ah Guided orotracheal intuhation in the operating room using a lighted stylet: A comparison with direct laryngoscopic technique. Anesthesiology 1986;64:823-826. 9. Fox DJ, Castro T, Rastrelli AJ: Comparison of intubation techniques in the awake patient: The flexi-lum surgical light (lightwand) versus blind nasal approach. Anesthesiology 1987; 66:69-71. 10. Ellis DG, Stewart RD, Kaplan RM, et ah Success rates of blind orotracheal intubation using a transillumination technique with a lighted stylet. Ann Emerg Med 1986;15:138-142. 11. Verdile VP, Heller MB, Paris PM, et ah Nasotracheal intubation in traumatic craniofacial dislocation: Use of the lighted stylet. A m J Emerg Med 1988;1:39-41. 12. Mishkel L, Wang JF, Gutierrez F, et ah Nasotracheal intubation by fiheroptic laryngoscope. South Med J 1981;74:1407-1409. 13. Donenfeld RF: A technique to aid blind na-
Annals of Emergency Medicine
17. Sleeman KW: An introducer to facilitate nasotracheal intubation. Anaesth Intens Care 1979;7:381-382. 18. Birmingham PK, Cheney FW, Ward RJ: Esophageal intubation: A review of detection techniques. Anesth Analg 1986;65:886-891. 19. Utting JE, Gray TC, Shelley FC: Human misadventure in anaesthesia. Can Anaesth Soc J 1979;26:472-478. 20. Stewart RD, Paris PM, Winter PM, et al: Field endotracheal intubation by paramedical personnel: Success rates and complications. Chest 1984~85:341-345. 21. Keenan RL, Boyan CPP: Cardiac arrest due to anesthesia: A study of incidence and causes. JAMA 1985;253:2372-2377. 22. Hammer M, Garry B: Transillumination of the trachea with flexilum (letter). Anesth Analg 1985;64:91-92. 23. Raybum RL: "Light wand" intubation (letter). Anaesthesia 1979;34:677-678. 24. Stewart RD, LaRosse A, Stoy WA, et ah Use of a lighted stylet to confirm correct endotracheal tube placement. Chest 1987;92: 900-903. 25. Stewart RD, Paris PM: Signs of endotracheal intubation in a field setting (letter). Ann Emerg Med 1985;14:t29-130. 26. Abarbanell NR: Esophageal placement of an endotracheal tube by paramedics: Problems with current management. A m J Emerg Med 1988;6:178-179. 27. Gold MI, Buechel DR: A method of blind nasal intubation for the conscious patient. Anesth Analg 1960;39:257-263.
510/43
