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PubMed2002

[Diagnosis and therapy of diseases of the larynx in the history of medicine].

BACKGROUND: FIRST CLINICAL APPROACHES. Bozzini in Frankfurt, Germany, in 1806 constructed the first endoscope, by which cavities of the human body could be inspected through a tube, but he was hardly able to demonstrate the larynx. His attempts were continued by Avery in London in 1840 with special view to the larynx but were not successful. Babington in London in 1829 constructed a glottiscope combining an angled mirror with a depressor for the tongue. He will probably have been able to inspect the larynx in some cases, but he did not continue these studies. Liston in London in 1837 reported that he had seen pathological findings of the larynx in a few cases by means of an angled mirror. FIELD OF RESEARCH: PHYSIOLOGY OF THE VOICE. Ferrein in Paris in 1741 was the first to carry out experiments on human larynges. These were continued in a systematic way by the physiologist Johannes Müller in Berlin in 1837 analysing the movements of the vocal cords. Manuel Garcia, a Spanish singing teacher, first in Paris, later in London, had studied the anatomy of the larynx very carefully, especially the muscle fibres. In 1855 he succeeded in inspecting his own larynx by means of an angled mirror and observed and described the movements of the vocal cords in great detail. At first his discovery did not arouse great attention, but later he was honoured very much as the inventor of laryngoscopy. SYNTHESIS OF PHYSIOLOGY AND CLINIC: Vienna 1857/58: The physiologist Carl Ludwig was preparing the second edition of his textbook on physiology, in which he extensively referred to Garcia's technique of laryngoscopy. His collegue Ernst Brücke was working on the physiological basis of phonetics. Johann Nepomuk Czermak, also a physiologist, was a guest of Brücke's and Ludwig's in Vienna during the winter 1857/58 and was inspired by the research work of his hosts. The neurologist Ludwig Türck had made experiments to visualize the human larynx in bodies and patients without knowing of Garcia's achievements. Since he used sun light only he had interrupted his studies in autumn 1857 and had lent his instrument, a mirror similar to that used by Garcia, to Czermak. Czermak used artificial light and the perforated concave mirror that had recently been introduced into ophthalmology. He was at once successful in inspecting his own larynx. He reported on this as early as March 1858 without informing Türck, although he mentioned him and the mirror that he had lent him. There was a public dispute about the priority between Türck and Czermak which drew wide attention to the invention of laryngoscopy which now was readily introduced in practical medicine forming the new discipline of laryngology. This development is delineated with many anecdotal details.

Europe↗

PubMed1998

[History of diaphanoscopy. Pictures from the history of otorhinolaryngology, illustrated by instruments from the collection of the Ingolstadt German Medical History Museum].

BACKGROUND: In 1854 the Spanish singing teacher Manuel Garcia succeeded in inspecting his own larynx. In 1857 the neurologist Ludwig Türck in Vienna, without knowledge of Garcia's achievement, had been experimenting on laryngoscopy with his patients using a small mirror and sunlight. When in the winter of 1857-1858 he had to suspend his experiments for lack of sunlight, he lent his mirror to physiologist Johann Czermak in Budapest. Czermak, using artificial light reflected by a perforated mirror, developed modern laryngoscopy within a few weeks and made it a clinically valuable method. He described it in March 1858 as his own invention. This was the beginning of a an embittered fight with Türck about whose development had priority. DIAPHANOSCOPY OF THE LARYNX: During his very first studies on laryngoscopy Czermak noticed that the interior of the larynx could be inspected very well when the neck was illuminated by a strong light from without and the mirror was held in the dark pharynx. The tissue would then appear transilluminated in a glowing deep red. When sufficiently bright electric lamps became available in 1889, Rudolph Voltolini in Breslau, Germany, took up the transillumination of the larynx and even carried out some minor intralaryngeal operations using this method. Although suitable diaphanoscopes were soon on the market this technique was not widely adopted. It was ony used once in 1954 (Pellnitz et al.) for diagnosing early stages of laryngeal cancer. DIAPHANOSCOPY OF THE PARANASAL SINUSES: Voltolini in Breslau and Cozzolino in Naples experimented independently of each other with small electric lamps with the aim of finding new techniques of rhinoscopy. Both of them placed their lamp in the nasopharynx and performed anterior rhinoscopy using an ordinary speculum. However, it was only Voltolini who noticed the transillumination of the maxillary sinuses when the lamp was placed in the oral cavity. On October 29, 1888, in Breslau he demonstrated diaphanoscopy of the maxillary sinus for the first time. Cozzolino claimed that he had introduced this technique prior to Voltolini. Voltolini had died in 1889 and could not comment on this. A careful study of the original publications, however, shows that Cozzolino had only inspected the nasal cavity with retronasal illumination, but had not demonstrated the maxillary sinus by transillumination. The diaphanoscopy of the paranal sinuses was very soon elaborated to perfection: Vohse in 1890 applied it to the frontal sinuses, Gerber in 1900 invented a double diaphanoscope for examining both frontal sinuses simultaneously. Although the shortcomings of diaphanoscopy soon became apparent, the method was widely used for about half a century, but in the end could not compete with modern techniques of radiography and ultrasound. The history is related in detail and illustrated with numerous figures.

Germany↗

PubMed1998

Management of meconium-stained neonates.

We examined the use of a new scoring system for the meconium-stained infant, which was designed to help the neonatologist decide on the appropriate therapeutic approach in the delivery room. Eighty meconium-stained infants were scored for: presence of fetal distress; meconium quality; performance of nasopharyngeal suctioning before the first breath and clinical condition in the first minute of life. Management consisted of gentle oropharyngeal suctioning or intubation and tracheal suctioning. Clinical outcome was compared with that of 100 meconium-stained infants born a year earlier. All babies in the control group underwent laryngoscopy and 30% were subsequently intubated. Universal laryngoscopy was not performed in the study group, and only 22.5% of these infants were intubated. The clinical outcome of the studied babies was identical to that of the newborns treated by the standard procedure. The use of the meconium intubation score eliminated the need for universal delivery room laryngoscopy for meconium-stained infants and significantly reduced the number of intubations performed.

Journal Article↗

PubMed1988

Anterior fontanelle pressure responses to tracheal intubation in the awake and anaesthetized infant.

In order to define the changes in intracranial pressure which occur during tracheal intubation in young infants, a Ladd transducer was used to monitor anterior fontanelle pressure (AFP) non-invasively in awake (group 1, n = 14) and anaesthetized (group 2, n = 10) infants during intubation of the trachea. Heart rate and systolic arterial pressure were also recorded. In quiet, undisturbed infants, AFP (mean +/- SEM) was similar in groups 1 (9.6 +/- 0.5 mm Hg) and 2 (8.7 +/- 0.8 mm Hg); with crying, AFP increased significantly in both groups. During laryngoscopy in group 1, AFP increased to 33.5 +/- 3.6 mm Hg, which was significantly greater than in the quiet infant, but did not differ significantly from measurements in the crying infant. In group 2, AFP increased significantly to 15.8 +/- 18 mm Hg during laryngoscopy. This increase was significantly less than the group 1 response. Neither heart rate nor systolic arterial pressure changed significantly in either group during laryngoscopy--when compared with measurements in the quiet state. It was concluded that AFP increases significantly during intubation and during crying in the infant. The response to intubation is only partially attenuated by the prior administration of general anaesthesia.

Anesthesia, General↗

PubMed2001

Use of angulated video-intubation laryngoscope in children undergoing manual in-line neck stabilization.

Laryngeal views obtained during direct laryngoscopy with and without manual in-line neck stabilization (MILNS) and during video-assisted intubation with MILNS using the angulated video-intubation laryngoscope were assessed in 100 paediatric patients (aged 0.25-17.3 yr). Visualization of the larynx (Cormack and Lehane score) as well as time taken for video-assisted tracheal intubation by six nurses and four resident anaesthetists not experienced in the technique were recorded. Cormack and Lehane scores were significantly worse during direct laryngoscopy when MILNS was applied. Video-assisted visualization of the larynx during MILNS produced scores, which were as good or better than those observed during direct laryngoscopy alone. Intubation times ranged from 19-75 s (mean 35 (SD 13.4); median 32).

Adolescent↗

PubMed1986

Effects of clonidine on narcotic requirements and hemodynamic response during induction of fentanyl anesthesia and endotracheal intubation.

The effects of clonidine, a centrally acting alpha 2-adrenergic receptor agonist, on depth of fentanyl anesthesia and on cardiovascular response to laryngoscopy and intubation were studied. Twenty-four patients undergoing aortocoronary bypass surgery (ACBS) with a history of arterial hypertension, coronary artery disease (NYHA class 3-4), and well-preserved left ventricular function were assigned randomly to either Group 1 (n = 12), who received standard premedication, or Group 2 (n = 12), who received clonidine 5 micrograms X kg-1 po in addition to standard premedication 90 min before estimated induction time. Depth of anesthesia was assessed by on-line aperiodic computerized analysis of the electroencephalogram (Lifescan EEG Monitor). Fentanyl was administered in 250-micrograms increments to shift the EEG to the 0.5-3-Hz frequency range (delta activity) in all subjects. In both groups, the anesthetic regimen effectively prevented hyperdynamic cardiovascular responses to laryngoscopy and intubation. No significant differences in measured or derived hemodynamic variables were observed between the two groups during the awake control period, except for stroke volume index (SVI), which was significantly greater in Group 1, 44 +/- 9 ml X beat-1 X m-2 compared with Group 2, 35 +/- 3.3 ml X beat-1 X m-2 (P less than 0.05). By contrast, fentanyl requirements in Group 2 were significantly reduced by 45% when compared with Group 1, i.e., from 110 +/- 23 to 61 +/- 19 micrograms X kg-1 (P less than 0.001). The authors conclude that at a similar anesthetic depth, as assessed by the EEG shift into the lower frequency range (0.5-3 Hz), a markedly reduced fentanyl dose effectively prevented the hyperdynamic cardiovascular response to laryngoscopy and intubation in the group of patients premedicated with clonidine. This is likely explained by the known synergistic inhibitory action of opiates and alpha 2-adrenoceptor agonists on central sympathetic outflow.

Adult↗

PubMed2003

Teaching with a video system improves the training period but not subsequent success of tracheal intubation with the Bullard laryngoscope.

BACKGROUND: The Bullard laryngoscope is useful for the management of a variety of airway management scenarios. Without the aid of a video system, teaching laryngoscopy skills occurs with indirect feedback to the instructor. The purpose of this study was to determine if use of a video system would speed the process of learning the Bullard laryngoscope or improve the performance (speed or success) of its use. METHODS: Thirty-six anesthesia providers with no previous Bullard laryngoscope experience were randomly divided into two groups: initial training (first 15 intubations) with looking directly through the eyepiece (n = 20), or with the display of the scope on a video monitor (n = 16). The subjects each then performed 15 Bullard intubations by looking directly through the eyepiece. RESULTS: There was not an overall significant difference in laryngoscopy or intubation times between the groups. When only the first 15 intubations were considered, the laryngoscopy time was shorter in the video group (26 +/- 24) than in the nonvideo group (32 +/- 34; P< 0.04). In the first 15 patients, there were fewer single attempts at intubation (67.9% vs 80.3%; P< 0.002) and more failed intubations (17.2% vs 6.0%; P< 0.0001) in the nonvideo group. CONCLUSIONS: In conclusion, the authors have shown that use of a video camera decreases time for laryngoscopic view and improves success rate when the Bullard laryngoscope is first being taught to experienced clinicians. However, these benefits are not evident as more experience with the Bullard laryngoscope is achieved, such that no difference in skill with the Bullard laryngoscope is discernible after 15 intubations whether a video system was used to teach this technique.

Female↗

PubMed2004

Anesthetic concerns of external maxillary distraction osteogenesis.

BACKGROUND: External maxillary distractions present additional anesthetic concerns to the existing complexity of the patient with craniofacial disorder. The distraction hardware is rigidly fixed to the cranium and projects in the frontofacial midline, thus limiting oronasal airway access. METHODS: A review of 16 patients (10 male, 6 female) having external maxillary distraction was done. Patients with patent tracheostomies were excluded. In all cases, the same type of external distraction device was used (R.E.D., K.L.S. Martin, Jacksonville, FL, USA). Perioperative records were reviewed for medical history; operative diagnosis, presence of airway disease, tracheostomy, laryngoscopy grade, use of fiberoptic bronchoscope, procedure, operative time, use of intraoperative steroid, day of postoperative extubation, and need for reintubation were documented. RESULTS: The study group was subdivided into two diagnostic categories: those with syndromic craniosynostosis (n = 9) and those with cleft lip/palate (CLP) (n = 7). Patients in the craniosynostotic group had grade 1 laryngoscopy views, with the exception of a single patient with Crouzon syndrome who had a grade 3 view. This was the only patient who required fiberoptic intubation. One patient with Apert syndrome required reintubation (48 hours after surgery); successful extubation was done 96 hours later. In the cleft lip/palate group, all patients had grade 1 laryngoscopic views, except one with a grade 3 view; no patient required fiberoptic intubation. Six of the seven patients were extubated immediately after surgery, with one patient extubated the next day. No patient experienced failure of extubation. CONCLUSIONS: External maxillary distraction minimally affects anesthetic management provided certain safeguards are observed. The vertical bar can be left attached to the cranial portion of the distractor, or it can be removed for extubation or reintubation. Removal of the vertical bar allows unobstructed direct laryngoscopy. This emphasizes the importance for the emergent availability of the appropriate screwdrivers and wire cutters to remove the vertical bar and trained personnel to perform the removal.

Adolescent↗

PubMed1981

Experience with a modified laryngoscope in sick infants.

critically ill infants receiving supplemental oxygen for their hypoxemia may become significantly compromised by hypoxemia and bradycardia when supplemental oxygenation is interrupted to carry out laryngoscopy and tracheal intubation. It would, therefore, be desirable to devise a means of maintaining supplemental oxygenation during the procedure. A modified laryngoscope blade achieved this objective simply and efficiently. A study was performed on 8 newborn infants with hyaline membrane disease(HMD) who required laryngoscopy and tracheal intubation for progressive hypoxemia. All infants were hypoxemic during the procedure of laryngoscopy, breathing room air (mean PaO2 43 torr). The procedure was repeated with the modified blade (mean PaO2 87 torr). No significant bradycardia was noted. The procedure of intubation was less stressful both to the patient and to the operator. It would seem appropriate to use the modified laryngoscope blade in all situations where hypoxemia threatens. It would seem to have a particular place in intubation of the difficult airway.

Humans↗

PubMed1984

Physiologic changes associated with endotracheal intubation in preterm infants.

Physiologic changes associated with endotracheal intubation were examined in 10 preterm infants. Laryngoscopy was associated with apnea and minor abnormalities in cardiac rhythm in 2 infants. Three infants had nasal airflow recordings which demonstrated obstructed breaths during laryngoscopy. Systolic blood pressure (BP) increased 47% when the trachea was intubated, whereas heart rate and transcutaneous oxygen tension (PtcO2) decreased. Because endotracheal intubation is a physiologically stressful procedure, personnel who intubate preterm infants must be skilled and experienced to minimize the duration of laryngoscopy and the number of intubation attempts.

Blood Pressure↗

PubMed1997

Multicenter, randomized, prospective trial of early tracheostomy.

OBJECTIVES: Determine the effect of early (days 3-5) or late (days 10-14) tracheostomy on intensive care unit length of stay (ICU LOS), frequency of pneumonia, and mortality, and evidence of short-term or long-term pharyngeal, laryngeal, or tracheal injury in head trauma, non-head trauma, and critically ill nontrauma patients. STUDY DESIGN: Randomized, prospective. SETTING: Five Level I trauma centers. METHODS: Data were obtained prospectively and included Acute Physiology and Chronic Health Evaluation III score (AIII), Glasgow Coma Scale score, Emergency Room Trauma Score, Injury Severity Score, Acute Injury Score, type of endotracheal tube or tracheostomy, level of positive end-expiratory pressure, and peak inspiratory pressure. Patients were to undergo laryngoscopy for detection of injury according to the Lindholm criteria at the time of endotracheal tube or tracheostomy removal and be reevaluated at 3 to 5 months after discharge. RESULTS: One hundred fifty-seven patients were entered, 127 to early randomization (3-5 days) and 28 to late randomization (10-14 days); however, only 112 patients with early and 14 with late randomization had completed data forms for the primary study goals. An additional 22 patients from the early entry groups were rerandomized late. Early randomization data: the AIII score was higher (p < 0.05) in the head trauma tracheostomy (65 +/- 4) than in the nontracheostomy group (51 +/- 4) and in the nontrauma tracheostomy (92 +/- 6) than in the nontracheostomy group (68 +/- 7), but was equivalent in the non-head trauma group. Glasgow Coma Scale score, Emergency Room Trauma Score, Injury Severity Score, Acute Injury Score, positive end-expiratory pressure, and peak inspiratory pressure were not significantly different in any of the groups. There were no significant differences in ICU LOS, frequency of pneumonia, or death in any of the groups after either early or late tracheostomy compared with continued endotracheal intubation. Only 83 patients underwent postextubation laryngoscopy. There were no significant differences between the groups; however, there were trends to more vocal cord ulceration and subglottic inflammation in the continued intubation group. No patient was seen in this study with late vocal cord or laryngeal stenosis; there were no tracheal-innominate artery fistulae. Seven of the patients with abnormal findings at extubation had normal 3- to 5-month postextubation laryngoscopy. CONCLUSION: Physician bias limited patient entry into the study. Although there were higher AIII scores in the head trauma early tracheostomy patients, there were no differences in the primary end points of ICU LOS, pneumonia, or death in any of the groups studied. Long-term endoscopic follow-up was poor, but no known late tracheal stenosis was seen.

APACHE↗

PubMed1987

Intranasal nitroglycerine attenuates pressor response to tracheal intubation in beta-blocker treated hypertensive patients.

The effect of intranasal nitroglycerine on the pressor response to laryngoscopy and tracheal intubation was studied in 40 adult hypertensive patients treated with beta-blocking drugs. Nitroglycerine 0.75 mg, administered intranasally 30 seconds before induction of anaesthesia, was compared with a placebo solution of saline. Haemodynamic variables were measured for 10 minutes after laryngoscopy and tracheal intubation. Heart rate did not change significantly in either group. Systolic as well as mean arterial blood pressure increased significantly for the first 5 minutes in the control group, whereas patients in the nitroglycerine group showed a decrease in systolic as well as in mean arterial pressure. No patient in the nitroglycerine group showed a decrease in systolic arterial pressure greater than 20 mmHg. In conclusion, intranasal nitroglycerine ameliorates the pressor response to laryngoscopy and tracheal intubation in beta-blocked patients.

Administration, Intranasal↗

PubMed1991

A comparative study of five different techniques to reduce left ventricular dysfunction during endotracheal intubation.

Thirty-five non-selected, consenting patients were studied during induction of anesthesia before coronary artery bypass grafting. Anesthesia was induced with diazepam, thiopentone and fentanyl, followed by pancuronium. Before induction, 200 MBq Tc 99 m - HSA was given i.v. and ejection fraction (EF) of the left ventricle was measured with a collimated single-crystal probe. The patients were allocated to five groups (seven patients in each) treated with: Group A: nitroglycerin i.v. bolus 4 micrograms x kg-1 given 30-60 s before laryngoscopy; Group B: nitroglycerin i.v. in continuous infusion, 1 micrograms x kg-1 x min-1 started before induction; Group C: two-stage topical anesthesia of the vallecula region and larynx with lidocain; Group D: a combination of nitroglycerin and topical anesthesia (as in Group B and C); and Group E: propranolol i.v. 0.01 mg x kg-1 given 5 min before intubation. All groups reacted in the same way during induction of anesthesia up to the point of laryngoscopy. End-diastolic volume and systemic arterial pressure decreased while cardiac index remained unchanged and EF increased. During laryngoscopy and intubation, however, differences between the groups were evident. Nitroglycerin i.v. as a bolus effectively prevented a reduction in EF and an increase in left ventricular volume. In addition to these beneficial hemodynamic effects, there was a moderate increase in heart rate and a reduction of stroke index. Continuous infusion of nitroglycerin and propranolol i.v. had no effect, since EF fell and left ventricular volume increased. Patients receiving topical anesthesia demonstrated a blunted response to endotracheal intubation with a moderate decrease in EF and an unchanged (Group C) or slightly increased (Group D) left ventricular volume.

Adult↗

PubMed1992

Does alfentanil preserve left ventricular pump function during rapid sequence induction of anaesthesia?

A double-blind, randomised trial was conducted in 24 patients without cardiopulmonary disorders (20-43 years), to assess the effect of an intravenous bolus of alfentanil on the circulatory and catecholamine responses to rapid sequence induction of general anaesthesia. Induction included injection of thiopentone 5 mg/kg and suxamethonium 1.5 mg/kg in rapid succession, followed by laryngoscopy and intubation. Half of the patients received alfentanil 100 micrograms/kg immediately before thiopentone. The other half received saline. Blood pressure, heart rate, and plasma catecholamine concentrations were measured repeatedly, together with left ventricular ejection fraction assessed by radionuclide angiocardiography. The responses following laryngoscopy and intubation were completely different in the saline vs. the alfentanil group: rate pressure product +76% vs. -32%, mean arterial blood pressure +46% vs. -25%, heart +46% vs. no change, noradrenaline +117% vs. -25%, adrenaline +50% vs. -53%, and left ventricular ejection fraction -32% vs. no change. In conclusion, during rapid sequence induction of anaesthesia with thiopentone and suxamethonium, an intravenous bolus of alfentanil 100 micrograms/kg 1 min before laryngoscopy and intubation completely prevents hypertension, tachycardia, decrease in left ventricular ejection fraction, and activation of plasma catecholamines, though at the expense of moderate hypotension.

Adult↗

PubMed2002

Role of GERD in chronic resistant sinusitis: a prospective, open label, pilot trial.

OBJECTIVE: The objective of this study was to determine whether aggressive medical therapy of gastroesophageal reflux disease (GERD) could improve both subjective and objective features of chronic resistant sinusitis (CRS). METHODS: Consecutive patients with CRS underwent assessment of GERD and sinus symptoms, esophageal motility testing, dual-channel esophageal pH testing, and laryngoscopy and nasal endoscopy at baseline. The results were compared to those of a group of GERD patients without sinus problems. The CRS patients alone then received omeprazole 20 mg b.i.d. for 3 months with symptom follow-up at monthly intervals. Laryngoscopy and nasal endoscopy were repeated at 3 months. RESULTS: Eleven patients with CRS and 19 GERD patients participated. Eight CRS patients experienced heartburn at least once weekly. Esophageal manometry and pH test results were similar between the two groups. Nine CRS patients had an abnormal pH test. All 11 CRS patients completed the 3-month course of omeprazole. Individual sinus symptoms (nasal congestion, nasal drainage, sinus pressure, facial headache, malaise) and global satisfaction were modestly improved in 25-89% and 91%, respectively, at 12 wk. Resolution of symptoms occurred infrequently. We identified no baseline variable that could predict symptom improvement. Although laryngoscopy and nasal endoscopy were abnormal in most CRS patients at baseline and improved in some after treatment, these changes did not parallel symptom improvement. CONCLUSION: In this small, prospective, open label study, we demonstrated a high prevalence of GERD in patients with CRS, many of whom experienced modest sinus symptom improvement after using omeprazole b.i.d. for 3 months. These findings warrant further randomized, controlled study in a larger patient population.

Adult↗

PubMedDate not supplied

Venturi jet ventilation through the metal endotracheal tube: a nonflammable system.

In an effort to design a fireproof and reliable method of ventilation during CO2 laser laryngoscopies, a new Venturi jet endotracheal tube coupler has been designed. This allows microdirect laryngoscopy. Its design features are described. Sixteen clinical cases of various laryngeal pathologies treated with direct laryngoscopy and laser excision are ventilated using this system. The clinical data and experiences are discussed. The arterial blood gases done at 20 minutes after muscular paralysis showed a median value of pH 7.45/PO2 252/PCO2 36. No complications or adverse effects were noted. The Venturi jet endotracheal tube coupler allows for jet ventilation through a metal endotracheal tube with reliable ventilation. This is an alternate, reliable, and fire-safe method during laser use.

Adult↗

PubMedDate not supplied

Effects of diazoxide on the cardiovascular response to tracheal intubation.

The efficacy of 2 or 3 mg/kg diazoxide given 2.5 min before laryngoscopy in attenuating the cardiovascular responses to laryngoscopy and intubation was studied in 30 patients undergoing elective surgery. Data were compared with those from 10 control patients receiving saline. Anaesthesia was induced using 5 mg/kg thiopentone given intravenously and tracheal intubation was facilitated with 0.2 mg/kg vecuronium bromide. Patients receiving saline showed a significant increase in mean arterial pressure and rate-pressure product associated with tracheal intubation. The increases following tracheal intubation were significantly reduced (P less than 0.05) in diazoxide-treated patients compared with those in the control group, but there were no significant differences in heart rate following tracheal intubation among the three groups. Data suggest that diazoxide can be used as a supplement during induction of anaesthesia to attenuate the hypertensive response associated with laryngoscopy and tracheal intubation.

Adult↗

PubMed1993

Attenuation of the cardiovascular and catecholamine responses to tracheal intubation with oral guanabenz.

We conducted a randomized, placebo-controlled, and double-blind study to evaluate the efficacy of oral guanabenz, an alpha 2-adrenergic agonist, in attenuating the cardiovascular and catecholamine responses to laryngoscopy and tracheal intubation in 30 normotensive (ASA physical status 1) patients undergoing elective surgery. They were allocated to one of three groups (n = 10 for each): placebo, 4 mg, or 6 mg of guanabenz groups. These tablets were administered 2 h before the induction of anesthesia. Anesthesia was induced with thiopental 5.0 mg/kg intravenously (IV), and tracheal intubation was facilitated by the administration of vecuronium, 0.2 mg/kg IV. During anesthesia, ventilation was assisted or controlled with 1% enflurane and 50% nitrous oxide in oxygen. Laryngoscopy lasting 30 s was attempted 2 min after the administration of thiopental and vecuronium. Patients receiving placebo showed a significant increase in mean arterial blood pressure, heart rate, and plasma catecholamine concentrations in response to tracheal intubation. These changes were significantly smaller in patients receiving either dose of guanabenz (P < 0.05). Oral administration of guanabenz before induction of anesthesia is a simple and effective method for attenuating the pressor and tachycardic responses to laryngoscopy and tracheal intubation with the drug acting at least partly via inhibition of the increases in plasma catecholamines concentrations.

Administration, Oral↗