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PubMed2005

Nalbuphine prevents haemodynamic response to endotracheal intubation.

OBJECTIVE: To determine the efficacy of nalbuphine in preventing the increase in heart rate and mean arterial pressure in response to laryngoscopy and orotracheal intubation. DESIGN: A comparative trial. PLACE AND DURATION OF STUDY: Department of Anaesthesia, Pakistan Naval Hospital Shifa, Karachi, Pakistan, from January 2001 to January 2002. PATIENTS AND METHODS: Forty healthy patients having general anaesthesia for elective surgery, were selected by convenient sampling to receive either saline [group I (control group); n= 20] or nalbuphine 0.2 mg/kg; (group II; n = 20) as a bolus dose, 5 minutes before laryngoscopy. Double blinding was done as the patient as well as the researcher was not aware of which study drug was being given. Heart rate (HR) and mean arterial pressure (MAP) were measured before induction of anaesthesia (time 1), just after intubation (time 2), then after every minute upto 5 minutes (time 3-7) and after 10 minutes of intubation (time 8). Twenty percent rise in heart rate (HR) and mean arterial pressure (MAP) was considered as significant. Data were analyzed by using SPSS version 10. Student's t-test was used for the significance of parameters at p < 0.05 and analysis of variance test (ANOVA) was interpreted for group analysis of the parameters. RESULTS: There was a significant increase (p <0.05) in heart rate (53.4%) in group I after intubation at time 2 compared with baseline at time 1, as compared to group II (15.5%). The HR gradually decreased during time 3 to 8 but still remained slightly higher than group II. MAP also increased significantly (p <0.05) in group I, at time 2 (43.6%) compared with baseline at time 1 as compared to group II (10.5%). The MAP also gradually decreased during time 3 to 8 but remained on slightly higher level than group II. CONCLUSION: Nalbuphine 0.2 mg/kg prevented a marked rise in heart rate and mean arterial pressure associated with laryngoscopy and orotracheal intubation.

Adult↗
PubMed1999

The effects of tramadol versus fentanyl in attenuating hemodynamic response following tracheal intubation.

BACKGROUND: Tramadol is a novel central acting analgesic. It has been used as a complement to general anesthesia and an effective agent for postoperative analgesia. However, the influence of tramadol on the hemodynamic response following laryngoscopy and tracheal intubation is less known. METHODS: Forty patients of both sexes, 16-50 year old, ASA physical status I or II, scheduled for elective surgery were randomly divided into equal groups in this prospective, double blind study. After obtaining the baseline data, the patient was given 3 micrograms/kg fentanyl (Group F) or 3 mg/kg tramadol (Group T). Then induction of anesthesia in a uniform and standardized manner was carried out by an anesthesiologist who was blind to the medication. The hemodynamic parameters were measured and recorded immediately after induction but prior to laryngoscopy, 3, 6, and 9 min after intubation, and before incision. We also observed any unusual effect in the postoperative care unit. Chi-square test, Student's t-test and paired t-test were used for statistical comparison. A P less than 0.05 was considered statistically significant. RESULTS: All patients had a successful induction and intubation. Differences in baseline values were not significant, nor were the differences in the values following induction. After laryngoscopy and intubation, heart rate increased significantly above the baseline level in both groups. The increase of heart rate was significantly more at 6 and 9 min (P < 0.05) and lasted longer in the tramadol group. After intubation, systolic, mean and diastolic arterial pressure (SAP, MAP, DAP) increased significantly above baseline in both groups too, except for DAP in fentanyl group. At 6 and 9 min, the MAP and DAP were significantly higher in tramadol than in fentanyl group (P < 0.05). Six patients in tramadol group had mild pain on injection of tramadol. CONCLUSIONS: When administered right before thiopental induction, 3 mg/kg tramadol did not display a better attenuation against the increase of hemodynamic profiles than did 3 micrograms/kg fentanyl following tracheal intubation.

Adolescent↗
PubMed2001

[Multicenter study on the usefulness of the NasOral system for the denitrogenation and apneic oxygenation in anesthesia].

OBJECTIVES: To study the usefulness of the NasOral system for denitrogenation prior to anesthetic induction for improving pulmonary oxygen storage that maintains SpO2 within the normal range during induced apnea and facilitates apneic oxygenation. MATERIAL AND METHODS: To establish the study population of 125, five hospitals of the Valencian Community (Spain) enrolled patients scheduled for elective procedures under general anesthesia. The patients were preoxygenated using the NasOral system (denitrogenation). For two minutes, the patients inhaled oxygen through the nose (FiO2 1) at a flow rate of 8-10 l/min (never less than the patient's own minute volume) and exhaled orally through a unidirectional valve. We measured time of apnea with SpO2 > or = 96% to assess the usefulness of the device for denitrogenation. We also measured PetCO2 after endotracheal intubation and after maximum time of apnea (< or = 10 minutes) to assess use of the device for apneic oxygenation during laryngoscopy. RESULTS: We found no significant differences with regard to age, sex, ASA or Mallampati classification among patient groups enrolled at the participating hospitals. Cox's regression analysis was used to determine relative risk of SpO2 < 96%. At 10 minutes post-apnea, 88.8% of all patients maintained SpO2 > or = 96%. However, SpO2 > 96% was maintained by 94.1% in the Mallampati I group and by 84.1% in the Mallampati II group. SpO2 fell below the cut-off (< 96%) in 33.3% of obese patients and in 7.5% of non-obese patients. Analysis of the likelihood of SpO2 < 96% associated with the variables of obesity, sex, age, ASA and Mallampati classification was significant only for obesity, for which a risk of 1.95 was calculated relative to non-obesity (95% CI 1.14-3.35). The NasOral system allows performance of direct laryngoscopy for oral tracheal intubation, maintaining oxygen flow through the permeable airway to facilitate apneic oxygenation. CONCLUSIONS: The NasOral system facilitates denitrogenation before induction of anesthesia in all patients with permeable nasal fossae as well as apneic oxygenation during laryngoscopy.

Adolescent↗
PubMed2001

Effectiveness and safety of rocuronium-hypnotic sequence for rapid-sequence induction.

BACKGROUND: Either succinylcholine or rocuronium administered after a hypnotic is the current technique for rapid-sequence induction. It is assumed that rocuronium administered before a hypnotic (Rocuronium-hypnotic sequence) may equally provide an acceptable intubation condition as well as a shorter period of apnea in rapid-sequence induction. We designed a prospective, randomized study to evaluate the effectiveness and safety of the technique in a similar rapid-sequence induction. METHODS: Ninety adult patients receiving elective surgeries were enrolled in this study. In all patients the procedure in the study began with i.v. injection of fentanyl 2 micrograms/kg, followed by preoxygenation with 100% O2 for 2 min. Afterward, the patients were randomly allocated to 3 groups with each group consisting of 30 patients. In Rocuronium-thiopental (Ro-Th) group the patients received rocuronium 0.6 mg/kg and then thiopental 5 mg/kg; in Th-Ro group the patients received thiopental 5 mg/kg and then rocuronium 0.6 mg/kg; and in Thiopental-Succinylcholine (Th-Sx) group, the control group, the patients received thiopental 5 mg/kg and then succinylcholine 1 mg/kg. Laryngoscopy and endotracheal intubation were performed 60 s after the injection of the muscle relaxant. The intubation condition, the apneal time before laryngoscopy, the intubation time, and total apneal time were investigated and compared. Presence of injection pain, sense of paralysis, SpO2 less than 95% during induction, and any unexpected adverse event were also recorded. RESULTS: Six patients (1 in Ro-Th group, 2 in Th-Ro group, and 3 in Th-Sx group, respectively) were excluded from the study. The intubation conditions were acceptable in all patients of three groups who completed the study, and as to excellent intubation condition there was no difference between the three groups. In Ro-Th group both the apneal time before laryngoscopy (32.4 +/- 5.4 s) and total apneal time (48.5 +/- 11.0 s) were the shortest. Th-Ro group (53.2 +/- 5.8 and 67.5 +/- 8.3 s, respectively) and Th-Sx group (54.4 +/- 5.8 and 68.4 +/- 7.7 s, respectively) were similar in both aspects. With respect to intubation time there was no significant difference among the three groups. Five patients in Ro-Th group and one patient in Th-Sx group felt mild injection pain. Three patients in Ro-Th group were noted to have diminished breathing during induction, which was not recalled during enquiry in the postoperative visit. One patient in Ro-Th group saw a fall of SpO2 down below 95% (94% the minimal) during the apnea period. CONCLUSIONS: Compared with traditional hypnotic-rocuronium or hypnotic-succinylcholine sequence, rocuronium (0.6 mg)-thiopental sequence can provide a similar intubation condition but cause a much shorter apneal period in rapid-sequence induction. In carrying out recuronium-thiopental sequence induction, maintaining a patent infusion line is essential to avoid drug precipitation and awareness of muscular weakness as a result of ill-timed action of thiopental.

Adult↗
PubMed2001

[Endotracheal intubation with a lighted stylet in a patient with difficult airway from the first and second brancheal arch syndrome].

A 28 year-old-woman with the first and second brancheal arch syndrome was scheduled for the lift of the inferior part of the right ear. Difficult intubation was expected because of the mandibular hypoplasia. We chose a lightwand stylet for tracheal intubation. Anesthesia was induced with sevoflurane slowly increased to 5% in nitrous oxide 3 l.min-1 with oxygen 3 l.min-1. A spiral tube with 6.5 mm inner diameter (Safety-Flex, Mallinckrodt Medical, Ireland) was attached to the lightwand stylet (Surch-Light, Aaron, U.S.A.) and shaped to fit to pharyngo-laryngeal curve. Under spontaneous breathing, the tube was successfully inserted without laryngoscopy. No traumatic events occurred. Usually fiberoptic laryngoscopy requires more skill, more expensive equipment, and more time to prepare than the lightwand stylet technique. Moreover profuse secretions or blood in the oropharynx sometimes inhibit clear vision by fiberoptic laryngoscopy. The lightwand stylet is simple and inexpensive and it is useful for tracheal intubation in patients with difficult airway from the first and second brancheal arch syndrome.

Abnormalities, Multiple↗
PubMed2006

Comparison of suxamethonium and priming with atracurium for rapid sequence orotracheal intubation in a Nigerian adult population.

OBJECTIVE: To compare suxamethonium with atracurium using the priming principle, for rapid sequence orotracheal intubation assessing onset time, time to successful laryngoscopy and intubation and quality of intubating conditions. PATIENTS AND METHODS: A prospective double-blind, randomised study was performed in 90 ASA physical status I and II patients aged between 18 and 64 years undergoing elective surgery requiring endotracheal intubation between October 2002 and June 2003 in a university teaching hospital . All patients were premedicated with 5-10mg oral diazepam and randomly assigned to one of two groups to receive either suxamethonium as a bolus dose (group A) or atracurium (priming with 0.05 mg/kg followed by 0.55 mg/kg after induction of anaesthesia) (group B). In both groups, the trachea was intubated when there was maximal muscle relaxation, determined clinically by jaw muscle relaxation. Muscle paralysis using a PNS, quality of intubating conditions, and occurrence of muscle weakness due to the priming dose of atracurium, time to laryngoscopy and onset time were all noted. RESULTS: Onset time was 87.1 +/- 25.60s and 135.8 +/- 46.23s in groups A and B respectively (P < 0.05). Group A had a laryngoscopy time of 73.6 +/- 25.22s compared to 107.7 +/- 41.32s in group B (P < 0.05). Intubating conditions were significantly better in group A compared to group B (P < 0.05). The frequency of muscle weakness from the priming dose of atracurium was 6.6%. CONCLUSION: Atracurium, using the priming principle, is an option in our environment for modified rapid sequence induction when suxamethonium is contraindicated.

Adult↗
PubMed1987

Ketanserin and the cardiovascular response to intubation: a preliminary report.

Several methods of attenuating the adverse cardiovascular effects of laryngoscopy and intubation are available. The obtunding effect of ketanserin 0.5 mg kg-1 versus that of a placebo, given 5 min prior to intubation, was investigated in a randomized double-blind trial in a group of 40 patients. Blood pressure (systolic, mean and diastolic) and pulse rate were measured at 1-min intervals with an Accutor blood pressure apparatus for 5 min before and 5 min after the injection of ketanserin or placebo, as well as for 6 min after a standardized induction (thiopentone and suxamethonium), laryngoscopy and intubation. The patients who had received ketanserin had a statistically significant lower systolic blood pressure (1 and 4 min), as well as significantly lower mean and diastolic blood pressures at 1, 2, 3 and 4 min. There were no unexpected untoward side-effects. Further investigations are suggested using ketanserin as part of a multi-faceted pharmacological approach to decrease the adverse effects of laryngoscopy and intubation.

Adult↗
PubMed1987

[The endocrine stress-reaction to orotracheal intubation and topical anesthesia with lidocaine].

The influence of laryngoscopy and intubation with or without topical lidocaine anesthesia on the endocrine stress response was investigated in six groups of 40 orthopedic surgery patients differing in premedication and technique of lidocaine application (one- or two-step method). Controls were included without lidocaine application. Plasma levels of catecholamines (by HPLC) were measured before induction and 1, 5, and 10 min after intubation, ADH-levels (by RIA) before induction and 5 and 10 min after intubation. In addition, mean arterial pressure (MAP, MAP), HR, and the incidence of coughing and cardiac arrhythmias were observed. The statistical evaluation (analysis of variance with repeated measures on one factor) considered P values of less than 0.05 significant. There was no influence of laryngoscopy and intubation on plasma catecholamine levels during the observation period. A continuous decrease in both levels of epinephrine and norepinephrine was significant. ADH levels showed no significant changes. Lidocaine had no influence on these endocrine parameters. MAP and HR increased after intubation in all groups studied. The increase in HR was less pronounced after lidocaine treatment. Coughing (4 patients) and ventricular dysrhythmia (2 patients) were observed only in patients without lidocaine treatment. In conclusion, no influence of different modes of treatment on the endocrine stress response during intubation became obvious. There was no indication that the cardiovascular symptoms during laryngoscopy and intubation are caused by systemic stress. An explanation may be a direct neural impulse via sympathetic efferents to the heart. On the other hand, topical application of lidocaine did prevent coughing and cardiac irritation, and the increase in HR was attenuated.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed1993

[A modified Macintosh blade for difficult intubation. The mirror blade].

Difficult intubations can occur in cases of anatomical or physiological abnormalities of the face and neck. They are frequently predictable when specific signs are evident preoperatively. There are still occasional unexpected difficulties during conventional laryngoscopy when common blades like the Macintosh and Foregger types are used. During the past 5 decades several authors have proposed many types of laryngoscopes and blades differing in length and shape, as well as various accessories such as guide-wires, prisms, and mirrors. METHOD. We modified a size 3 Macintosh blade by adding a mirror placed tangential to the external curve near the apex. This configuration allows both conventional direct visualisation of the vocal cords and non-direct viewing through the mirror. Insertion of the tube is facilitated using a specially shaped guide-wire. RESULTS. This equipment was used for orotracheal intubation in 20 patients with different degrees of direct laryngeal visibility prior to otolaryngologic endoscopy and surgery under general anaesthesia. Both methods of larynx visualisation were performed and compared. In 1 patient the mirror was not useful because it became fogged. In all the others we could avoid this problem by warming the blade in water. Only in 1 other case was the conventional view better and intubation seemed to be easier than when the mirror was used. In 15 patients the vocal cords were visualised better with the mirror, and intubation was performed by means of the guide-wire with the non-direct technique. In 2 of these cases difficult direct laryngoscopy of grades 3 and 4 according to the Cormack and Lehane classification was found. Four patients were difficult to intubate and neither type of laryngoscopy was ideal. It is notable that a satisfactory view was achieved in the mirror with much less effort. In particular, there was no need to introduce the blade as deeply or raise its apex as much as is usually done. CONCLUSION. The mirror-blade is a suitable device for management of unexpected difficult intubations. Because of its dual availability, it offers both direct and non-direct visualisation of the larynx. Handling of this mirror-blade can be practised extensively, which allows integration of this equipment in the "failed intubation drill". This should be an integral part of the teaching and training of anaesthesia personnel.

Adult↗
PubMed1995

The application of a modified mini-flexible-fiberoptic endoscopy in pediatric practice.

BACKGROUND: The application of bronchoscopy in infants and small children is still restricted in most institutions because of their limited airways. The purpose of this study was to evaluate the usefulness of a modified mini (2.1 mm OD) flexible fiberoptic endoscope (FFE) in diagnosis and therapy of suspected pediatric airway problems. METHODS: A prospective two-year study was carried out in a tertiary care neonatal/pediatric intensive care unit and general ward in a children medical center of a university-affiliated hospital. The employed mini-FFE (Machida ENT-30 F III, Tokyo, Japan) was modified with the addition of an external silastic catheter (0.5 mm inward diameter, 0.9 mm outward diameter) for suctioning, oxygen delivery, and medications during study. RESULTS: Totally, 247 laryngoscopies and 212 bronchoscopies were performed in 207 patients without significant morbidity or any associated mortality. The age of patients ranged from 1 day to 10 years. About one-fifth of the procedures (larngoscopy 21.5%, 53/247; bronchoscopy 19.8%, 42/212) were performed in patients under the age of one month. Patient's body weight ranged from 650 g to 40 kg. About fifty-five percent of the procedures (laryngoscopy 55.1% 136/247; bronchoscopy 55.2%, 117/212) were performed in patients weighing less than 5 kg. The most common path of either laryngoscopy (94.3%, 233/247) or bronchoscopy (94.8%, 201/212) was through the nasal route. In 102 patients who had been demonstrated to have upper airway problems, 16 patients (15.7%) also proved to ahve significant lesion(s) below the glottis. CONCLUSIONS: This modified FFE is a safe and a valuable instrument that can serve as an important aid in the diagnosis and therapy as well as a guide for surgical intervention of respiratory tract disorders in small infants and children.

Bronchoscopes↗
PubMed2003

Office-based lower airway endoscopy in pediatric patients.

BACKGROUND: Office-based evaluation of the lower airway in adults with only topical anesthetics has been well documented. This study was performed to assess the feasibility of performing office-based lower airway endoscopy in a pediatric population. DESIGN: One hundred five consecutive pediatric patients requiring flexible laryngoscopy were studied. All received only a topical anesthetic-decongestant applied nasally. After flexible laryngoscopy, the endoscope was passed below the vocal folds to visualize the subglottis, trachea, and carina. All evaluations were videotaped for later review. SETTING: Academic pediatric otolaryngology practice. MAIN OUTCOME MEASURES: All 105 patients were studied for complications and agreement between office endoscopy and operative endoscopy when necessary (performed in 20 patients). A subset of 24 consecutive patients were studied for ease of performing the lower airway evaluation, rated on a 3-point scale: 1, unable to perform; 2, performed with some difficulty; and 3, performed without difficulty. The ability to view the subglottis, trachea, and carina were also rated on a 3-point scale. RESULTS: There were no complications for any of the procedures. Office endoscopy correlated with operative endoscopy in all cases. In the subset of 24 patients, the mean score for ease of endoscopy was 2.83. The mean scores for visualizing the lower airway were 2.91 for the subglottis, 2.80 for the trachea, and 2.24 for the carina. CONCLUSION: With the use of only topical anesthesia, flexible endoscopy of the lower airway in children can be performed in the office setting and can be used effectively to evaluate abnormalities of the lower airway.

Chi-Square Distribution↗
PubMed1996

Laryngomalacia. The search for the second lesion.

OBJECTIVES: To determine the necessity of rigid endoscopy in the diagnosis and management of laryngomalacia and its associated synchronous airway lesions (SALs), to analyze the incidence of SALs associated with laryngomalacia and their significance, and to determine the need for epiglottoplasty in management of laryngomalacia. DESIGN: Retrospective medical chart review. SETTING: Tertiary care children's hospital. PATIENTS: Two hundred thirty-three patients with a primary diagnosis of laryngomalacia on flexible fiberoptic laryngoscopy treated at the Children's National Medical Center, Washington, DC, from January 1, 1984, to June 30, 1994. INTERVENTION: Evaluation and treatment of laryngomalacia and associated SAL by flexible fiberoptic laryngoscopy, radiographic studies, rigid endoscopy, and other surgical procedures. MAIN OUTCOME MEASURES: Resolution of airway symptoms from laryngomalacia and associated SAL. RESULTS: Ninety patients (38.6%) underwent rigid endoscopy, and 12 patients (5.2%) required epiglottoplasty. Synchronous airway lesions were discovered in 44 patients (18.9%). Eleven patients (4.7%) had SALs that wre considered clinically significant; nine (3.9%) of these required surgical intervention. CONCLUSIONS: Rigid endoscopy in evaluation of an infant with laryngomalacia is rarely necessary. Clinically significant SALs requiring surgical intervention are uncommon. Surgical intervention for laryngomalacia also is rarely necessary.

Airway Obstruction↗
PubMed1997

Pretherapeutic staging of hypopharyngeal carcinoma. Clinical findings, computed tomography, and magnetic resonance imaging compared with histopathologic evaluation.

OBJECTIVES: To assess the accuracy of preoperative computed tomography (CT), magnetic resonance imaging (MRI), and clinical and endoscopic tumor evaluation and to analyze the impact of these diagnostic modalities on pretherapeutic staging of hypopharyngeal carcinoma. DESIGNS: Prospective study of 44 consecutive patients with hypopharyngeal carcinoma undergoing surgical resection. SETTING: Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital, Bern, Switzerland. METHODS: All patients underwent contrast-enhanced CT, MRI at 1.5 T, indirect laryngoscopy, and direct laryngoscopy. The surgical specimens were cut in whole-organ slices parallel to the plane of the axial CT and MRI scans. The histologic findings were compared with the findings of the different diagnostic modalities. RESULTS: The main tumor site was misdiagnosed by endoscopy in 7 (16%) of 44 patients and by CT and MRI in 16 (36%) of 44 patients. Neoplastic invasion of cartilage was present in 21 (48%) of 44 laryngectomy specimens. Magnetic resonance imaging was more sensitive in detecting neoplastic invasion of cartilage than CT (97% vs 68%; P = .002). Magnetic resonance imaging was less specific than CT (62% vs 84%; P = .02), taking into account the thyroid and cricoid cartilages. There was no difference between the overall accuracy of CT and MRI in detecting neoplastic invasion of cartilage (78% vs 75%). Clinical and endoscopic evaluation failed to correctly stage 16 (36%) of 44 patients. Combined clinical and CT evaluation and combined clinical and MRI evaluation failed to correctly stage 12 and 13 of 44 patients, respectively. CONCLUSIONS: The assessment of tumor site is more accurate using endoscopic evaluation than CT or MRI. Magnetic resonance imaging is more sensitive in detecting neoplastic cartilage invasion than CT, whereas CT is more specific. Clinical and endoscopic evaluation of tumor stage alone fails to identify invasion of the laryngeal framework. Therefore, many tumors staged pT4 are clinically understaged. The preoperative staging accuracy was improved by combining the information gained using both clinical evaluation and CT or MRI. However, there was no difference in the staging accuracy between CT and MRI.

Adult↗
PubMed1992

Severe laryngotracheobronchitis complicating measles.

OBJECTIVE: To determine the incidence of severe measles-related laryngotracheobronchitis in patients hospitalized during a recent measles epidemic and to evaluate factors associated with severity of airway injury and its management. DESIGN: Clinical description of patient series. SETTING: Children's hospital and county general hospital, Houston, Tex. PATIENTS: One hundred twenty-four children (aged 1 month to 19 years) admitted with a diagnosis of measles. INTERVENTIONS: None. MEASUREMENTS/RESULTS: Twenty-seven patients had significant laryngotracheobronchitis, including 10 who had not received appropriate immunization. Six patients required endotracheal intubation for relief of upper airway obstruction. The median age of patients requiring intubation was 12 months (range, 4 to 24 months). Two patients died of complications of superinfection. Two patients survived but required prolonged intubation. Two patients underwent early diagnostic laryngoscopy and bronchoscopy and required shorter artificial airway maintenance. CONCLUSIONS: Severe laryngotracheobronchitis frequently occurs in patients younger than 2 years hospitalized with measles and may be related to bacterial or viral super-infection. Early diagnostic laryngoscopy and bronchoscopy for injury assessment and possible endotracheal tube exchange are recommended and, in some severe cases, tracheostomy should be considered to shorten artificial airway maintenance and decrease the incidence of airway complications.

Adolescent↗
PubMed1999

Anatomy of the internal branch of the superior laryngeal nerve.

The purpose of this study was to determine the length and distribution of the branches of the internal branch of the superior laryngeal nerve (ibSLN) and describe the initial afferent pathway for the laryngeal cough reflex (LCR). On 25 sides of 19 cadaver specimens, the ibSLN and its branches were dissected from the greater cornu of the hyoid to the mucosa of the larynx and laryngopharynx. The location of these terminal fibers were confirmed by direct observation and fiberoptic laryngoscopy. In 21 specimens, the ibSLN coursed 6.95+/-3.71 mm before piercing the thyrohyoid membrane and splitting into superior, middle, and inferior rami. Four specimens split proximal to the thyrohyoid membrane. The superior ramus distributed to the mucosa of the piriform recess. In this study the large, middle ramus was a new finding and distributed branches to the mucosa of the vestibule of the larynx, specifically the quadrangular membrane. The length of the ibSLN from the greater cornu to the end of the middle ramus at quadrangular membrane was 28.52+/-4.61 mm. The termination of these fibers were confirmed by observation and direct laryngoscopy. The middle ramus probably conveyed the afferent component of the laryngeal cough reflex. The inferior ramus did not distribute to the vestibular mucosa.

Afferent Pathways↗
PubMedDate not supplied

Computed tomography of the larynx: a clinical and pathologic study.

Recent interest in the application of computed tomography (CT) to the evaluation of laryngeal tumors, and the fact that the larynx offers the unique opportunity of whole organ study after total laryngectomy, led to a prospective study of laryngoscopy, conventional tomography, and CT in relation to pathologic findings. The results showed that CT gives an exact assessment of laryngeal anatomy and tumor involvement, particularly in the paracordal and pre-epiglottic spaces. The laryngeal cartilages, which are not well demonstrated by any other means, are accurately delineated by CT. There is also good demonstration of the laryngeal surface of the epiglottis, including the anterior commissure, which is poorly shown by other radiologic methods and is sometimes poorly seen on laryngoscopy. Because CT and conventional tomography present images at 2 different planes, at right angles to each other, we believe that CT is entirely complementary to conventional tomography.

Adult↗
PubMed2005

Exercise-induced stridor due to abnormal movement of the arytenoid area: videoendoscopic diagnosis and characterization of the "at risk" group.

We evaluated 4 patients who developed severe, symptomatic stridor during maximal cardiopulmonary exercise testing, all referred due to exercise-related dyspnea. All underwent resting, unsedated transnasal fiberoptic laryngoscopy and had normal findings. Four patients performed repeat maximal exercise testing with fiberoptic laryngoscopy, and they form the basis of this report. They had normal vocal cord motion during exercise, but developed abnormal anterior motion of the arytenoid and aryepiglottic folds only at peak exercise, leading to partial airway obstruction and severe stridor. This report details the workup and characterizes patients at risk for this unusual phenomenon.

Adolescent↗
PubMed1996

Computer simulation of cerebrovascular circulation: assessment of intracranial hemodynamics during induction of anesthesia.

OBJECTIVE: The purpose of this project was to develop a computer model of cerebrovascular hemodynamics interacting with a pharmacokinetic drug model to examine the effects of various stimuli on cerebral blood flow and intracranial pressure during anesthesia. METHODS: The mathematical model of intracranial hemodynamics is a seven-compartment, constant-volume system. A series of resistance relate blood and cerebrospinal fluid fluxes to pressure gradients between compartments. Arterial, venous, and tissue compliance are also included. Autoregulation is modeled by transmural pressure-dependent, arterial-arteriolar resistance. The effect of a drug (thiopental) on cerebrovascular circulation was simulated by a variable arteriolar-capillary resistance. Thiopental concentration was predicted by a three-compartment, pharmacokinetic model. The effect site compartment was included to account for a disequilibrium between drug plasma and biophase concentrations. The model was validated by comparing simulation results with available experimental observations. The simulation program is written in VisSim dynamic simulation language for an IBM-compatible PC. RESULTS: The model developed was used to calculate the cerebral blood flow and intracranial pressure changes that occur during the induction phase of general anesthesia. Responses to laryngoscopy and intubation were predicted for simulated patients with elevated intracranial pressure and non-autoregulated cerebral circulation. Simulation shows that the induction dose of thiopental reduces intracranial pressure up to 15%. The duration of this effect is limited to less than 3 minutes by rapid redistribution of thiopental and cerebral autoregulation. Subsequent laryngoscopy causes acute intracranial hypertension, exceeding the initial intracranial pressure. Further simulation predicts that this untoward effect can be minimized by an additional dose of thiopental administered immediately prior to intubation. CONCLUSION: The presented simulation allows comparison of various drug administration schedules to control intracranial pressure and preserve cerebral blood flow during induction of anesthesia. The model developed can be extended to analyze more complex intraoperative events by adding new submodels.

Anesthesia, General↗