Combining the EndoFlex tube with fiberoptic bronchoscopy in difficult intubation.

We applied a combination technique using the EndoFlex tube with fiberoptic bronchoscopy for a 69-year-old man presenting with limited mouth opening and neck movement. Awake nasotracheal intubation was performed under conscious sedation with propofol and fentanyl. After positioning the tip of the EndoFlex tube in the oropharynx, the fiberoptic bronchoscope was inserted into the tube until the tip reached the bevel of the tube. Anterior flexion of the distal tip of the EndoFlex tube facilitated uncomplicated insertion of the tube into the trachea without impingement on the arytenoids. Fiberoptic visualization confirmed that the distal-tip flexing mechanism of the EndoFlex tube corrected the direction of the tube tip anteriorly, allowing entry into the trachea. We present a case where this technique proved valuable for tracheal intubation in a patient with limitations of mouth opening and neck movement.

Accumulated oropharyngeal water increases coughing during dental treatment with intravenous sedation.

In dental procedures performed under intravenous sedation in patients with intellectual disabilities, procedures are sometimes interrupted by the cough reflex, which may be triggered by intraoral use of water and/or increased secretion stimulating the pharyngeal/laryngeal mucosa, or by those irritating the tracheal mucosa directly through anesthetics-induced impairment of the laryngeal closure reflex. We investigated relationships between frequency of coughing episodes and intraoral use of water, water remaining in the oropharyngeal space, and mean infusion rate of propofol during dental treatments performed under intravenous sedation with midazolam and propofol. Twenty-one intellectually disabled patients were enrolled. After induction, a 14 Fr. suction catheter was inserted nasally, which was fixed where oropharyngeal suction could be done most effectively. Patients were divided into three groups according to the amount of intraoral use of water, amount of oropharyngeal suction and mean infusion rate of propofol. The amount of oropharyngeal suction significantly correlated with intraoral use of water. Frequency of coughing episodes significantly correlated with amount of oropharyngeal suction per minute. However, coughing episodes correlated neither with intraoral use of water nor with infusion rate of propofol. These findings suggested that accumulation of water in the oropharynx increased vulnerability to the cough reflex in dental treatments performed under intravenous sedation.

Intravenous sedation for dental patients with intellectual disability.

BACKGROUND: The poor quality of oral health care for people with intellectual disability (ID) has been recognized, and the strong fears about dental treatment suggested as a major reason for disturbances of visits to dentists by such patients. Intravenous sedation is a useful method for relieving the anxiety and fear of such patients about dental treatment, and is frequently essential for ID patients undergoing dental treatment. However, decision regarding the dose of sedative required to be administered for an adequate level of sedation is difficult because the effect of sedation cannot be adequately assessed in patients with severe ID. As an appropriate sedative dose for dental patients with ID has not been fully established, we investigated sedative doses required and the effect of sedation in patients with ID, compared with other dental patients. METHODS: We reviewed the anaesthetic records of dental patients with ID (73 cases) and other dental patients (19 cases) aged between 20 and 29 years who had undergone intravenous sedation with midazolam and propofol in Okayama University Dental Hospital, from January 2000 to December 2000. Intravenous sedation was induced with a bolus intravenous administration of midazolam (2-3 mg) and maintained with a continuous infusion of propofol. The dose of propofol was titrated to achieve an adequate level of sedation: asleep but responding to painful stimulation. The efficacy of sedation, the required doses of propofol, and the wake-up times were investigated for all subjects. The efficacy of sedation was evaluated by judging whether the patient became cooperative and allowed the dental treatment to be carried out or not. The complications induced by intravenous sedation were also evaluated in each subject. Differences in variables between subjects with ID and other subjects were analysed using the Mann-Whitney U-test. RESULTS: Intravenous sedation was effective for dental treatment in all subjects with or without ID. The required dose of propofol in subjects with ID was 4.74 mg/kg/h (2.63-10.33 mg/kg/h), significantly higher than that required for other subjects (3.31, 1.72-4.80 mg/kg/h). Wake-up times of subjects with ID were similar to those of the other subjects. Severe complications were not seen during or after intravenous sedation. CONCLUSION: The results of this study show that intravenous sedation is a useful method for dental patients with ID as well as for other dental patients, but indicate that dental patients with ID need higher doses of sedative to obtain an adequate level of sedation.

Subcutaneous epinephrine administration decreases lower oesophageal sphincter pressure and gastro-oesophageal pressure gradient in children under general anaesthesia.

BACKGROUND AND OBJECTIVE: Children are vulnerable to regurgitation with a relatively high incidence of aspiration during general anaesthesia which is attributed to the high intragastric pressure, a short oesophagus, an immature laryngeal reflex and incomplete lower oesophageal sphincter muscle function. Subcutaneous administration of epinephrine is generally used in surgery to decrease bleeding due to local vasoconstriction. The effect of epinephrine on the sphincter muscle tone was investigated during general anaesthesia in children. METHODS: Ten children scheduled for skin graft or plastic surgery of the ear were studied. A gastrointestinal pressure sensor was inserted nasally, and the intraluminal pressures of the lower oesophagus, lower oesophageal sphincter and stomach were monitored under sevoflurane, nitrous oxide anaesthesia. The effect of epinephrine on the lower oesophageal sphincter muscle tone was measured. RESULTS: The resting pressure of the lower oesophageal sphincter muscle tone significantly decreased from 4.56 +/- 1.85 to 3.79 +/- 1.11 kPa after 3 microg kg(-1) epinephrine for 4 min. The barrier pressure is the difference between the lower oesophageal sphincter and intragastric pressure, and that decreased to 1.23 +/- 1.17 kPa from the 2.07 +/- 1.77 kPa resting level. The observations implied that epinephrine had a long-lasting relaxing effect on lower oesophageal sphincter muscle in children. CONCLUSIONS: The observations may give some explanation about the mechanism of gastro-oesophageal reflux during general anaesthesia, especially in the participation of the adrenergic receptors.

Effect of midazolam on interleukin-6 mRNA expression in human peripheral blood mononuclear cells in the absence of lipopolysaccharide.

Midazolam, a benzodiazepine, has an hypnotic effect via benzodiazepine receptors and is widely used as an anaesthetic. Recently, it has been suggested that benzodiazepines modulate cytokine responses. The purpose of the present study was to evaluate the effect of midazolam on interleukin-6 (IL-6) response by observing mRNA expression levels in human peripheral blood mononuclear cells (PBMCs) in the absence of lipopolysaccharide (LPS). PBMCs were isolated from healthy volunteers in endotoxin-free 0.9% sodium chloride solution. The cells were incubated for 2 h at 37 degrees C immediately after isolation. IL-6 mRNA expression levels in the cells were quantified using reverse transcription and competitive polymerase chain reaction. It was found that midazolam time-dependently inhibited the IL-6 mRNA expression in PBMCs in the absence of LPS, and significantly inhibited the IL-6 mRNA expression at 1 microg/ml (P<0.05) or 10 microg/ml (P<0.01) in the absence of LPS. However, neither a specific agonist of peripheral-type benzodiazepine receptors, Ro5-4864, nor a specific agonist of central-type benzodiazepine receptors, clonazepam, inhibited IL-6 mRNA expression. These findings indicated a suppression of the IL-6 response in human PBMCs by midazolam in the absence of LPS, and suggests that midazolam has its effect not via benzodiazepine receptors, but by another mechanism.

Intravenous anesthetics inhibit nonadrenergic noncholinergic lower esophageal sphincter relaxation via nitric oxide-cyclic guanosine monophosphate pathway modulation in rabbits.

BACKGROUND: Nonadrenergic noncholinergic (NANC) nerves have important roles in the regulation of the lower esophageal sphincter (LES) motility and function. The effects of thiopental, ketamine, and midazolam on NANC LES relaxation were investigated. METHODS: The isometric tension of circular muscle strips from Japanese White rabbits was examined. The NANC relaxation was induced by KCl (30 mM) in the presence of atropine (3 x 10(-6) M) and guanethidine (3 x 10(-6) M). The modifications of the NANC and sodium nitroprusside (SNP; 10(-5) M)-induced relaxation by the anesthetics were examined. The content of 3',5'-cyclic guanosine monophosphate (cGMP) was measured by radioimmunoassay. RESULTS: The KCl-induced relaxation was abolished by pretreating with tetrodotoxin (10(-6) M). The NANC relaxation was inhibited in the presence of N(G)-nitro-L-arginine (L-NNA; 3 x 10(-5) M), methylene blue (10(-6) M), apamin (10(-7) M), and glibenclamide (10(-5) M). The SNP-induced relaxation was inhibited by methylene blue but was not affected by tetrodotoxin, L-NNA, apamin, or glibenclamide. Ketamine (EC50 = 8.8 x 10(-5) M) and midazolam (EC50 = 4.8 x 10(-6) M) suppressed the NANC response in a concentration-dependent manner, leaving SNP-induced response unchanged. Thiopental altered neither of the relaxations. cGMP content was decreased in the presence of ketamine and midazolam. CONCLUSION: The NANC relaxation was mediated by nitric oxide and by low-conductance calcium- and adenosine triphosphate-sensitive potassium channels of smooth muscle. The modulation of the nitric oxide-cGMP pathway was related, at least in part, to the inhibitory actions of ketamine and midazolam on the NANC LES relaxation.

Incidence of deep fascial space infection after surgical removal of the mandibular third molars.

Nine hundred and ninety-three patients who underwent surgical removal of the mandibular third molars with oral antibiotic prophylaxis were examined to determine the incidence of postoperative deep fascial space infection and its background factors. Postoperative deep fascial space infection was observed in 8 of the patients (0.8%; 4 males and 4 females), and submandibular spaces were involved in all infected patients. Only 1 of these 8 patients was an immune compromised host. Patients aged 30 years or more had a significantly higher incidence of deep fascial space infection than those aged under 30. Five patients had partial bony impactions and 3 had complete bony impactions. However, the incidence of infection according to the molar positions was not significantly different between partial bony impaction and complete bony impaction. The 8 patients had not had pericoronitis preoperatively. The clinical courses of all were favorable after antibiotics were administered intravenously. In conclusion, the incidence of deep fascial space infection after removal of the mandibular third molars was low, at 0.8%. However, it may be desirable to remove the molars, if applicable, at a younger age because of the higher incidence of infection in patients aged over 30. The results of this study also offer information that will be useful as a basis for obtaining informed consent from patients whose mandibular third molars are to be removed.

A patient whose cerebral aneurysm ruptured soon after an operation to remove a maxillary cyst.

A hypertensive woman complained of a headache soon after an operation to remove a maxillary cyst. A computed tomogram showed evidence of subarachnoid haemorrhage and on angiogram an aneurysm of an anterior cerebral artery. The aneurysm was treated by clipping and the patient recovered.

Subdural empyema after tooth extraction in which Capnocytophaga species was isolated.

We describe a patient with meningitis and a subdural empyema arising from an infection after teeth extraction in which Capnocytophaga species was detected. The patient was a 54-y-old man without any underlying diseases. A computerized tomography scan showed a subdural empyema 21 d after the extraction.

Effects of sevoflurane and enflurane on lower esophageal sphincter pressure and gastroesophageal pressure gradient in children.

PURPOSE: The effects of sevoflurane and enflurane on the intraluminal pressure of the lower esophagus (LE), lower esophageal sphincter (LES), and stomach were investigated in paralyzed and mechanically ventilated children under general anesthesia. METHODS: A total of 14 children, ASA physical status class I without risk factors for regurgitation, scheduled for orthopedic surgery were studied. After induction of anesthesia, we inserted a gastrointestinal pressure sensor nasally and monitored the intraluminal pressure of the LE, LES, and stomach under various concentrations of sevoflurane or enflurane with 66% nitrous oxide in oxygen prior to surgical incision. The barrier pressure (BrP), which is the difference between LES pressure and intragastric pressure, was calculated. RESULTS: Sevoflurane at 2.0 and 2.5 minimum alveolar concentration (MAC) decreased LES pressure, and enflurane at 2.0 and 2.5 MAC decreased both LES pressure and BrP in anesthetized children. The intraluminal pressure of the LE and stomach were not altered in either group. CONCLUSION: Sevoflurane and enflurane have an inhibitory effect on LES smooth muscle in anesthetized children. However, since the reduction was relatively low, even at high concentrations, these inhalation anesthetics are unlikely to influence gastroesophageal reflux during anesthesia.

The relaxing effect of ketamine on isolated rabbit lower esophageal sphincter.

We used ketamine to investigate the effects and intracellular mechanisms of several anesthetics on strips of lower esophageal sphincter (LES) from rabbits. Ketamine induced dose-dependent relaxation of LES preparations. It increased the content of 3',5'-cyclic adenosine monophosphate (cAMP) dose-dependently, but decreased that of 3',5'-cyclic guanosine monophosphate (cGMP). Pretreatment with nicotinic acid, an inhibitor of adenylate cyclase, along with atropine to block neurogenic effects, antagonized ketamine-induced relaxation. Pretreatment with N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride (H-89), a selective antagonist for cAMP-dependent protein kinase, similarly antagonized the relaxant effect of ketamine. Cholera toxin and dibutyryl cAMP induced LES relaxation. However, dibutyryl cGMP induced little LES relaxation, and pretreatment with NG-nitro-L-arginine or methylene blue did not alter the relaxant effect. Atropine, propranolol, phentolamine, vasoactive intestinal peptide (VIP) antagonist, and tetrodotoxin did not affect the ketamine-induced relaxation. This response, however, was potentiated in the presence of indomethacin or diphenhydramine. Ketamine-induced relaxation was inhibited in the presence of verapamil. These findings suggest that ketamine induces relaxation of LES, in part, by modulating the activity of adenylate cyclase and in part by inhibiting transmembrane influx of Ca2+.

Effects of various peptides on isolated rabbit lower esophageal sphincter.

Strips of lower esophageal sphincter (LES) from rabbits were tested for their responses to several peptides, and to electrical field stimulation (EFS) under the presence of some peptides. Substance P (SP), motilin, and bombesin induced contraction, and vasoactive intestinal peptide (VIP) induced relaxation. SP- and bombesin-induced contractions were antagonized by SP antagonist. VIP-induced relaxation was antagonized by phentolamine and VIP antagonist. Pretreatment with atropine, phentolamine, and diphenhydramine antagonized the motilin- and bombesin-induced contraction. Pretreatment with tetrodotoxin (TTX) attenuated the motilin- and bombesin-induced contraction, but not the SP-induced contraction and VIP-induced relaxation. EFS induced contraction, which was attenuated by TTX. Calcitonin gene-related peptide and neuropeptide Y had no effect on LES; however, they attenuated EFS-induced contraction. These findings suggest some characteristic peptidergic involvement in rabbit LES smooth muscle.