Local Nerve Block Anesthesia for Peroral Endoscopy

Transcription

1 Local Nerve Block Anesthesia for Peroral Endoscopy Tom R. DeMeester, M.D., David B. Skinner, M.D., Richard H. Evans, M.D., and Donald W. Benson, M.D. ABSTRACT Local glossopharyngeal and superior laryngeal nerve block anesthesia for peroral endoscopy was performed on 500 patients (313 bronchoscopies, 162 esophagoscopies, 25 combined bronchoesophagcnscopies). The technique allows easy insertion of rigid and flexible scopes or awake tracheal intubation of conscious patients. Glossopharyngeal nerve block causes temporary abolition of the gag reflex and loss of tactile sensation over the posterior third of the tongue and the lateral and postenor wall of the oropharynx and hypopharynx. Superior laryngeal nerve block results in loss of tactile sensation over the posterior surface of the epiglottis and the mucosa of the larynx and upper trachea. Ten of the 500 patients (2%) had an inadequate glossopharyngeal block, and 4 of the 313 patients who had a bronchoscopic examination had an inadequate superior laryngeal block. In the remaining patients, excellent anesthesia was obtained with good patient acceptance and minimal morbidity. Topical local anesthesia is currently the technique of choice for peroral endoscopy. For esophagoscopy, a topical anesthetic agent is applied to the mucosa of the oropharynx and hypopharynx. For bronchoscopy, a topical transmucosal block of the internal branch of the superior laryngeal nerve is performed by placing anesthetic-soaked applicators in the pirifonn sinuses. The anesthetic agent is dripped onto the vocal cords and laryngeal mucosa using indirect visualization. These procedures are not only time consuming and uncomfortable for the patient, but they fail to fully eliminate the gag reflex, which arises from two modes of From the Departments of Surgery and Anesthesiology, the University of Chicago Pritzker School of Medicine, Chicago, IL. Presented at the Thirteenth Annual Meeting of The Society of Thoracic Surgeons, Jan 24-26, 1977, San Francisco, CA. Address reprint requests to Dr. DeMeester, Department of Surgery, The University of Chicago, 950 E 59th St, Chicago, IL peripheral stimulation, those of touch and pressure [ll. The topically administered anesthetics, while blocking the tactile receptors in the mucosa, are unable to block the deeper pressure receptors in the posterior third of the tongue. These pressure receptors can still initiate the gag reflex upon insertion of endoscopic instruments. Although the advent of fiberoptic endoscopy has made the endoscopic procedure more comfortable for the patient, topical anesthesia is still required, and patient gagging can be troublesome. Four years ago one of us, during attempts to measure differential oxygen uptake by bronchospirometry in awake and nonmedicated patients, accidentally discovered an anesthetic technique for tracheal intubation. A local anesthetic agent was injected into the posterior pharynx of these patients in a manner similar to what one would do in removing the tonsils under local anesthesia. To our surprise, the gag reflex, which previously had been a problem, was temporarily abolished. A search in the medical literature revealed that we were making use of the little-known glossopharyngeal nerve block [ll. With some modification in our original technique, we have used this glossopharyngeal nerve block for rigid and fiberoptic esophagoscopy, and in combination with superior laryngeal nerve block [2] for rigid and fiberoptic bronchoscopy. Over the past 30 months we have used these blocks in more than 500 patients and have found them to be safe and extremely helpful in making the peroral endoscopic examination a comfortable experience. Technique The patient receives no medication before entry into the endoscopy unit. On arrival, the patient is placed on the endoscopic table in a sitting position similar to that assumed while in a dental chair. A mixture of 25 to 50 mg of meperidine and 1 to 1.5 mg of diazepam is slowly adminis- 278

2 279 DeMeester et al: Local Anesthesia for Peroral Endoscopy Glossopharyngeal Nerve. Fig 1. Sagittal view showing the location of the injection site in the lateral oropharyngeal wall 0.5 cm behind the midportion of the posterior tonsillar pillar. tered intravenously through a scalp vein infusion set. Atropine (0.4 mg) is given intravenously to those patients who have excessive tracheal secretions. The electrocardiogram is monitored routinely during the endoscopic procedure. The glossopharyngeal nerve block is performed using a finger-controlled 10 cc syringe and an angled 23-gauge tonsil needle with 1 cm of the shaft exposed at its tip.* Five milliliters of 1% lidocaine is injected into the lateral oropharyngeal wall at a point 0.5 cm behind the midportion of the posterior tonsillar pillar, which is recognized as the posterolateral continuation of the soft palate (Fig 1). This can be done easily, after a 5% cocaine spray to the back of the throat, by using a tongue blade in one hand to expose the posterior tonsillar pillar and injecting the lidocaine with the other hand using the finger-controlled syringe. The needle is inserted laterally and slightly posteriorly until the 1 cm shaft is buried in the lateral pharyngeal *Available from Becton-Dickinson and Company, Rutherford, NJ wall. At this point, the tip is adjacent to the glossopharyngeal nerve. An attempt to aspirate blood is made prior to slow injection. If blood is aspirated, the needle is withdrawn and reinserted at an adjacent point. If the patient complains of headache during the injection, it should be stopped immediately. The same procedure is repeated on the opposite side. Patients frequently complain at this point of inabiiity to swallow, but when instructed to do so, they are readily able. If only esophagoscopy is to be performed, no additional anesthesia is necessary. If bronchoscopy is required, the superior laryngeal nerve is also blocked. To perform this block, the index finger is placed between the hyoid bone and the easily palpable posterior superior border of the thyroid cartilage. The carotid pulsation can be felt immediately underneath the finger when properly placed. With the finger in this position, the internal branch Q the superior laryngeal nerve pierces the thyrohyoid membrane just anterior to the fingertip (Fig 2). A 22-gauge needle penetrates the skin just above the fingertip and is advanced medially in a slightly posteroinferior direction on a plane aimost parallel with the ciavicle, through the thyrohyoid membrane, and into the larynx. Entrance into the larynx usually occurs at a depth of 1 to 1.5 cm and is signified by the ability to aspirate air. The needle is then withdrawn until air can no longer be aspirated, and 2 ml of 1% lidocaine is injected. The same procedure is repeated on the opposite side. If air cannot be aspirated, the local anesthetic should not be injected since this may cause swelling of the mucous membrane around the orifice of the larynx, making observation of the inlet to the larynx difficult. If difficulty in aspirating air is encountered, the procedure may be modified by introducing a needle so as to contact the thyroid cartilage. Using this as a depth guide, the needle is moved up and over the superior margin of the cartirage and advanced in a posteromedial direction through the thyrohyoid membrane and into the larynx. With the patient in the recumbent position and the neck flexed, a laryngoscope can be inserted with ease and comfort to provide a direct view of the piriform sinus, laryngeal opening, and vocal cords, and the trachea. Both rigid and

3 280 The Annals of Thoracic Surgery Vol 24 No 3 September 1977 f Internal Branch of Superior Laryngeal Nerve Fig2. Position of the indexfinger and point of needle insertion in performing the superior laryngeal nerve block. flexible bronchoscopes can be passed with equal ease. The only additional anesthesia necessary is occasional administration through the bronchoscope of a topical agent (5% cocaine) to the mucosa of the distal bronchial tree to alleviate the cough reflex. The majority of the blocks were performed by one of our surgical residents, so the results obtained should be reproducible by any physician endowed with average technical skill and are not due to the ability of any one endoscopist. Results Five hundred endoscopic examinations were performed with local nerve block anesthesia; 162 patients had esophagoscopy using only glossopharyngeal nerve block, 313 had bronchoscopy using glossopharyngeal nerve block in combination with superior laryngeal nerve block, and 25 had combined bronchoesophagoscopy using both nerve blocks. Esophagoscopy was performed with either the rigid or fiberoptic scope; in 17 patients both were used. Bronchoscopy was performed with either the rigid or fiberoptic scope; in 55 patients, both were used. Glossopharyngeal nerve block caused tempo- rary and complete obliteration of the gag reflex and loss of tactile sensation over the lateral and posterior wall of the oropharynx, the hypopharynx, and the posterior third of the tongue. The superior laryngeal nerve block caused loss of tactile sensation Over the posterior surface of the epiglottis, the mucosa of the larynx proper, and the upper trachea (Fig 3). Both blocks lasted for approximately 45 to 60 minutes. Failure of adequate glossopharyngeal block occurred in 10 of the 500 patients (2%). In all 10 patients, we were unable to perform the examination due to continued gagging on attempts to insert the endoscope despite what was considered to be adequate glossopharyngeal nerve block. In 8 patients, anxiety secondary to insufficient sedation may have caused these failures. In 2 patients, marked spasm or narrowing of the cricopharyngeal muscles added to the difficulty of inserting the esophagoscope. Four of the 313 patients who had bronchoscopy (1.2%) experienced excessive discomfort on insertion of the bronchoscope, indicating inadequate superior laryngeal nerve block. The only complications due to blocking the glossopharyngeal nerve were related to the potential for intravascular injection and the consequences of blocking the afferent nerve fibers from the carotid sinus. In 6 patients, blood was aspirated prior to injection of the local anesthetic. In this situation, the needle was removed

4 281 DeMeester et al: Local Anesthesia for Peroral Endoscopy iny. Only 1 of the arrhythmias, a tachycardia, required temporary treatment with propranolol. No infections occurred even though the injection was made through the contaminated field of the oropharynx. A total of 11 complications from glossopharyngeal block were observed, resulting in an overall complication rate of 2%. There were no complications secondary to superior laryngeal nerve block. Eight patients (1.6%) had a complication related to the endoscopy procedure itself, and not to the local nerve block anesthesia. A tooth was broken in 2 patients. One patient experienced an asthma attack during the procedure, which necessitated its termination. Five patients with markedly limited pulmonary function had a respiratory arrest during the procedure; they were adequately resuscitated. Fig3. Sagittalview showing the area of anesthesia obtained with a glossopharyngeal and superior laryngeal nerve block. and reinserted in an adjacent area. In all 6 instances, no local hemorrhage occurred. Four additional patients (0.8%) complained of headache during and following the glossopharyngeal nerve block. The headache was unilateral, confined to the supraorbital, temporal, and parietal areas of the skull, and persisted for approximately two hours after the block. In 1 patient the headache persisted for three days and required relief with pain medication. The headache is thought to have been due to an unrecognized partial intraarterial injection of local anesthetic, since it occurred simultaneously with the injection. Two patients (0.04%) had a seizure during the endoscopic examination; 1 episode was associated with hypoxia, and the second occurred in a patient who had a known seizure disorder. Although it is possible that the seizures were due to intraarterial injection of lidocaine, the timing of the seizures in relation to administration of the block makes it unlikely. Five patients (1%) developed an arrhythmia following glossopharyngeal nerve block; 4 had supraventricular tachycardia and 1 had bigem- Comments The importance of glossopharyngeal nerve block is that in addition to blocking tactile receptors in the mucosa, it abolishes the troublesome gag reflex arising from pressure-sensitive receptors in the posterior third of the tongue. The contribution of tactile receptors to the gag reflex has long been recognized by endoscopists, and these receptors are controlled easily with topically administered anesthetics. Peripheral blocking of the glossopharyngeal nerve interrupts both the tactile and pressure stimuli of the gag reflex without affecting adjacent vagal motor nerve fibers, since the patients continue to swallow on command. Clinically, we are impressed by the ease with which a laryngoscope can be used to view the larynx or insert an oral or nasotracheal tube in patients under a glossopharyngeal nerve block. Both rigid and flexible bronchial and esophageal scopes can be inserted with surprisingly little difficulty. This allows interchanging between flexible and rigid scopes during the same examination, and is a distinct advantage when large biopsy specimens are desired and are within reach of a rigid scope. The use of both the glossopharyngeal and superior laryngeal nerve blocks has reduced our need for preoperative medication. All patients arrive at the endoscopy unit without medication, and only a small intravenous injection of

5 282 The Annals of Thoracic Surgery Vol 24 No 3 September 1977 meperidine and diazepam is given prior to performing the blocks to combat apprehension. The combined block is also useful when a patient requires awake nasotracheal intubation for respiratory support or preanesthetic orotracheal intubation. In the former situation, internasal anesthesia is obtained in addition to the blocks using 5% cocaine nasal packs. The effective elimination of gagging while the nasotracheal tube is passed allows direct visualization of the larynx if necessary, and provides additional safety against vomiting and aspiration, known hazards of awake intubation. There was a 2.4% complication rate with the use of glossopharyngeal nerve block due to either simultaneous blocking of the carotid sinus nerve, which gave rise to arrhythmias, or to intraarterial injection, signified by the presence of an immediate headache. It is unlikely that the arrhythmias were due to vagal blockade, since all the patients were able to phonate. Intraarterial injection is the most dangerous potential complication of performing a glossopharyngeal nerve block. Our experience shows that if care is taken to aspirate sufficiently prior to slow injection of the anesthetic agent, the possibility of intraarterial injection is rare. If the patient complains of headache, the injection should be aborted immediately. The possibilities of introducing an infection by means of an injection through a necessarily contaminated field are real, but no such complication was encountered. We believe that if care is taken to aspirate prior to the injection of a local anesthetic, the benefits of the glossopharyngeal nerve block outweigh the risk to the patient. At superior laryngeal nerve block was performed in addition to the glossopharyngeal nerve bloclk in those patients who had tracheal intubation for fiberoptic endoscopy or rigid bronchoscopy. It was used as a means of effectively anesthetizing the mucosa of the posterior surface of the epiglottis, the larynx proper, and the upper trachea. Of the two blocks used for bronchoscopy, the superior laryngeal is the most difficult due to the occasional problem experienced in placing the needle within the larynx. With practice, this becomes easier and one gains an appreciation for how well this block complements the glossopharyngeal block in bronchoscopy. We have elected to perform fiberoptic bronchoscopy through an indwelling endotracheal tube in patients with compromised pulmonary function or excessive secretions. This allows easy reinsertion of the scope when the lens needs cleaning and provides a route for assisted ventilation when necessary. The presence of an indwelling endotracheal tube was extremely helpful in the resuscitation of 5 patients who had a respiratory arrest during the procedure, and reflects the safety of its use, particularly in patients who have marginal respiratory function. References 1. Barton S, Williams JD: Glossopharyngeal nerve block. Arch Otolaryngol93:186, Gaskill JR, Gillies DR: Local anesthesia for peroral endoscopy. Arch Otolaryngol84:654, 1966 Discussion DR. L. PENFIELD FABER (Chicago, IL): I compliment Dr. DeMeester on his presentation, but I cannot compliment him on his method of anesthesia. Anesthesia for endoscopy can be accomplished by several methods, the most popular being topical application of the anesthetic and methods of general anesthesia. Superior laryngeal nerve block has been known for many years, having been described in Pitkin s text of conduction anesthesia in It has never been popular as a major form of anesthesia for peroral endoscopy. This is probably related to reluctance of physicians to utilize needle injections into the throat and mouth, which may render some patients apprehensive and, at the same time, be difficult to accomplish. We have used topical anesthesia for flexible and rigid tube endoscopy in several thousand cases at Presbyterian-St. Luke s Medical Center in Chicago. We rarely resort to general anesthesia for endoscopy, and the majority of our procedures are done with a flexible fiberoptic bronchoscope. The pharynx is sprayed with 2% Xylocaine; 5 to 7 ml of 4% Xylocaine is then instilled on and through the vocal chords, utilizing indirect mirror laryngoscopy. This method offers a panoramic view of the larynx and vocal chords. Small nodules or lesions on the vocal chords can be readily recognized and true vocal chord motility is assessed pri9r to instillation of the anesthetic agent. Comparable examination by Dr. DeMeester s technique requires a Hopkins laryngoscope or careful assessment with the flexible bronchoscope. I could well foresee that small or peripheral lesions might be missed. Complications with topical Xylocaine are rare, and if the endoscopist utilizes a measured dose, reactions will be almost nonexistent. After observing Dr. DeMeester and the nerve block technique, I have utilized the method in4 patients. In

6 283 DeMeester et al: Local Anesthesia for Peroral Endoscopy 2, hypopharyngeal swelling partially obscured the vocal chords and made insertion of the scope difficult; minor bleeding occurred in 1. The latter could be confusing in a patient with hemoptysis. Placement of the endotracheal tube does cause some bucking on the tube in both Dr. DeMeester s hands and mine until additional topical agent is instilled. This method affords greater depth of anesthesia, and the patient tolerates the rigid bronchoscope well. The technique is accomplished rapidly, which can be helpful when several patients are being examined. Any method of local anesthesia has the potential for systemic reaction, but needle injection into the highly vascular neck or accidental intravascular injection will increase morbidity. Fiberoptic esophagoscopy is easily done using Tessalon pearls or viscous Xylocaine, and needle injection is not necessary for this procedure. A 5% morbidity, headache, and arrhythmia unassociated with hypoxia are not problems of topical anesthesia. Local nerve block is faster and provides greater depth of anesthesia. I would recommend that anyone who is unhappy with his present method of anesthesia attempt Dr. DeMeester s method. It will have no advantages for those who are currently satisfied. After trying the procedure myself, I will continue to use topical anesthesia. DR. ROBERT GINSBERG (Toronto, Ont, Canada): I agree that the simple method of topical anesthesia is quite sufficient for bronchoscopy and esophagoscopy. A further simple technique other than spray is that of having the patient gargle with less than 10 ml of 4% Xylocaine. This produces total anesthesia of the pharynx, and on insertion of the fiberoptic scope, another 1 ml on the chords and upper trachea produces anesthesia there. The possible complications of needles are avoided, and this method provides complete anesthesia in all cases. I would advocate topical anesthesia rather than injection of local anesthetic. DR. DEMEESTER: The point of the glossopharyngeal nerve block is that it obliterates the gag reflex, which is the most uncomfortable aspect of endoscopy. In actual fact, the gag reflex generates from two afferent stimuli, those of touch and pressure. A topical anesthetic will get rid of the tactile sensation but not the pressure stimulus, which a glossopharyngeal nerve block does. We were pleased to have Dr. Faber observe two of these nerve block procedures prior to discussing this paper. Unbeknownst to him, 1 of the patients was a referral from Presbyterian-St. Luke s Medical Center where he works. The patient came to us with the complaint that the endoscopy he had experienced was very unnerving, and he had morbid dread of going through the procedure again. Unfortunately, Dr. Faber left before we could do the second case, so I can understand why he had trouble with his first 4 patients [laughter].