[Successful fiberoptic tracheal intubation guided by Airwayscope with a thin Intlock blade in a patient with severe rheumatoid arthritis]

We present a case of anticipated difficult airway with severe rheumatoid arthritis in which intubation with fiberoptic bronchoscope (FOB) assisted by Pentax-AWS Airwayscope with the thin Intlock (AWS T) was effective. A 69-year-old woman was scheduled to undergo laparoscopic cholecystectomy for acute cholecystitis in a previous hospital. Tracheal intubation with Glidescope or nasal intubation was unsuccessful and abandoned due to mucosal injury and bleeding. Ventilation via several supraglottic airway devices was unsatisfactory, while mask ventilation was easy after induction of anesthesia. She was referred to our hospital for application of veno-arterial extracorporeal life support in case of 'cannot ventilate and cannot intubate'. We planned to perform tracheal intubation preserving spontaneous breathing under intravenous administration of dexmedetomidine and fentanyl. We could visualize the epiglottis, but could not set the target mark to the invisible glottis with AWS-T. Finally, we could accomplish uneventful tracheal intubation with FOB along with the Intlock's guides of AWS-T.

Suspected migration of cervical epidural catheter into the brainstem after a difficult catheter insertion

We report a case of diplopia during continuous epidural injection presumably caused by catheter migration. A 61-year-old woman underwent shoulder surgery under general anesthesia with cervical epidural anesthesia. The epidural catheter was placed in the C6-C7 epidural space with some difficulty before general anesthesia. The depth of the catheter placed under the skin was 10 cm. On POD 2, the patient noticed diplopia and developed dysarthria despite of good pain control so far. She complained of sudden headache after the rate of continuous epidural infusion was increased to relieve postoperative pain. Computed tomography and T2-weighted cerebral magnetic resonance imaging revealed an air image and surrounding edema in the pons. Diplopia and dysarthria disappeared after ceasing continuous epidural injection. A 15-cm-long mark under the skin and leak of colorless clear fluid from the puncture site were noted at removal of the catheter. On POD 13, diplopia recurred, which improved gradually. On the 9-month radiologic follow-up, we considered that the symptoms on POD 2 were caused by migration of the epidural catheter into the pons and that her later diplopia was induced by intracranial hypotension syndrome. One should be aware that such an unexpected migration of the catheter can occur following a difficult insertion.

[General anesthesia in a orthopedic case with the Kommerell's diverticulum of right-sided aortic arch diagnosed on preoperative examination]

Kommerell's diverticulum is a rare anomaly of the aortic arch. A 59-year-old man was scheduled for open reduction and internal fixation of his right proximal tibial fracture under general anesthesia. We diagnosed right-sided aortic arch by the chest X-ray and thoracic computed tomography. His trachea and esophagus were compressed by the aortic arch. He had complained of no dyspnea or dysphagia. Respiratory difficulty might be caused by muscle relaxants, intermittent positive pressure ventilation, change of intrathoracic pressure, postural change and overloaded infusion during general anesthesia in a case of right-sided aortic arch. We performed lumbar epidural anesthesia and inserted an i-gel after general anesthesia induction preserving spontaneous respiration in preparation for controlled ventilation or tracheal intubation via an i-gel. We could accomplish the operation uneventfully and he was discharged on POD 53. A supraglottic airway such as an i-gel was a useful device in the present case of right-sided aortic arch with Kommerell's diverticulum.

Effects of head-neck extension on abnormality of laryngeal mask airway function resulting from opening the mouth

PURPOSE

This study investigated the effects of head-neck extension on abnormalities of laryngeal mask airway (LMA) function resulting from opening the mouth.

PATIENTS AND METHODS

A single, experienced LMA user inserted the LMA in 15 patients scheduled for elective oral surgery. Oropharyngeal leak pressure and intracuff pressure were sequentially documented in 5 mouth conditions in order (0 minutes, mouth closed plus 0° extension; 3 minutes, mouth open plus 0° extension; 6 minutes, mouth open plus 15° extension; 9 minutes, mouth open plus 30° extension; and 12 minutes, mouth open plus 45° extension).

RESULTS

Oropharyngeal leak pressures with the mouth open plus 0° extension (30.7 ± 5.6 cm H(2)O, P < .001), mouth open plus 15° extension (29.1 ± 6.8 cm H(2)O, P < .001), and mouth open plus 30° extension (25.7 ± 6.1 cm H(2)O, P < .001) were significantly higher than with the mouth closed plus 0° extension (19.7 ± 2.8 cm H(2)O). Compared with the position with the mouth closed plus 0° extension (60.0 ± 0 cm H(2)O), intracuff pressures were also higher with the mouth open plus 0° extension (84.5 ± 14.1 cm H(2)O, P < .001), mouth open plus 15° extension (77.4 ± 11.0 cm H(2)O, P < .001), and mouth open plus 30° extension (73.6 ± 9.6 cm H(2)O, P < .001). Both measurement values returned to control levels when the position with the mouth open plus 45° extension was assumed (oropharyngeal leak pressure, 64.5 ± 6.5 cm H(2)O [P = .212]; intracuff pressure, 20.2 ± 4.9 cm H(2)O [P = .969]).

CONCLUSIONS

In procedures requiring the patient to have an open mouth under general anesthesia using LMA, 45° head-neck extension achieves acceptable airway conditions.

Optimal degree of mouth opening for laryngeal mask airway function during oral surgery

PURPOSE

This study was performed to determine the optimal degree of mouth opening in anesthetized patients requiring laryngeal mask airway (LMA) during oral surgery.

PATIENTS AND METHODS

A single, experienced LMA user inserted the LMA in 15 patients who were scheduled for elective oral surgery. Oropharyngeal leak pressure, intracuff pressure, and fiberoptic assessment of the LMA position were sequentially documented in 5 mouth conditions-opening of 1.4 (neutral position), 2, 3, 4, and 5 cm-and any resulting ventilatory difficulties were recorded.

RESULTS

Oropharyngeal leak pressure with the mouth open 4 cm (21.8 ± 3.2 cm H(2)O, P = .025) and 5 cm (27.3 ± 7.2 cm H(2)O, P < .001) was significantly higher than in the neutral position (18.1 ± 1.5 cm H(2)O), as was intracuff pressure (neutral position, 60.0 ± 0 cm H(2)O; 4 cm, 72.6 ± 5.1 cm H(2)O [P < .001]; and 5 cm, 86.9 ± 14.4 cm H(2)O [P < .001]). LMA position, observed by fiberoptic bronchoscopy, was unchanged by mouth opening, being similar in the 5 mouth conditions (P = .999). In addition, ventilation difficulties (abnormal capnograph curves or inadequate tidal volume) occurred in 2 of 15 patients (13%) and 7 of 15 patients (53%) (P < .001) with the mouth opening of 4 and 5 cm, respectively.

CONCLUSIONS

This study showed that a mouth opening over 4 cm led to substantial increases in oropharyngeal leak pressure and intracuff pressure of the LMA, warranting caution, because gastric insufflation, sore throat, and ventilation difficulties may occur. A mouth opening of 3 cm achieves acceptable airway conditions for anesthetized patients requiring LMA.

The influence of mouth opening on oropharyngeal leak pressure, intracuff pressure, and cuff position with the laryngeal mask airway

PURPOSE

The aim of this study was to investigate the influence of mouth opening on oropharyngeal leak pressure, intracuff pressure, and cuff position of the laryngeal mask airway (LMA).

PATIENTS AND METHODS

Fifteen patients who were scheduled for elective oral surgery were recruited into this study. A single, experienced LMA user inserted the LMA according to the manufacturer's recommended technique. Oropharyngeal leak pressure, intracuff pressure, and fiberoptic assessment of the LMA position were documented under 3 mouth conditions: neutral position (1.4-cm distance between upper and lower incisors), mouth open (5- to 6-cm distance between upper and lower incisors), and return to the neutral position. Any ventilation difficulties under the 3 mouth conditions were recorded.

RESULTS

Oropharyngeal leak pressure with the mouth open was higher than in the neutral position (P < .001). Compared with the neutral position, intracuff pressure was also higher with the mouth open (P < .001). Both measurement values returned to control levels when the neutral position was once again assumed. The LMA position observed by fiberoptic bronchoscopy was unchanged by mouth opening and was similar in the 3 mouth conditions (P = .998). Although ventilatory difficulties occurred after mouth opening in 8 of 15 patients (P < .001), it did not occur when the neutral position was reassumed.

CONCLUSIONS

This study showed that mouth opening led to substantial increases in oropharyngeal leak pressure and intracuff pressure of the LMA, warranting caution because gastric insufflation, sore throat, and ventilation difficulties may occur.

[Successful fiberoptic tracheal intubation via Cobra PLA in a patient with an epiglottic tumor]

A 59-year-old woman with an epiglottic tumor was scheduled for the total removal of the mass by laryngomicrosurgery. The patient had no preoperative respiratory symptoms. During the induction of anesthesia, the mask ventilation was easily accomplished; however, when rigid laryngoscopy was attempted, an epiglottic tumor prevented exposure of the vocal cords. After a size 3 Cobra PLA had been placed, a size 6.5 mm reinforced tube was threaded over a fiberoptic bronchoscope through the Cobra PLA into the trachea. Post-extubation course was uneventful. The Cobra PLA can be a good alternative supraglottic airway device allowing easy tracheal intubation for difficult airway.

[Anesthetic management for high-intensity focused ultrasound (HIFU) therapy in prostate cancer patients]

HIFU therapy is one of epoch-making, low-invasive treatments for prostate cancer. We investigated 71 patients who had undergone HIFU therapy from June 2004 through September 2005. We mainly gave a single spinal injection followed by epidural catheterization with a combined spinal-epidural anesthesia kit. Three patients received general anesthesia because of various problems such as allergy for local anesthetics, ankylosing spondylitis and severe spinal deformity causing difficulty in lumbar puncture. Spinal anesthesia was successfully achieved in most patients. Twelve patients with insufficient anesthetic levels required additional local anesthetics via epidural catheters. We found no serious perioperative complications.

Selective brain hypothermia suppresses noxious-evoked movement in canines

Systemic hypothermia suppresses noxious-evoked movement, but its main site of action is unknown. We examined the effect of hypothermia in the brain on noxious-evoked movement by selectively cooling the brain. Sixteen beagles were randomly divided into two groups and anesthetized with isoflurane/oxygen. After being deeply anesthetized, the dogs' lungs were artificially ventilated, and several major vessels were cannulated for perfusion and monitoring. Cold lactate Ringer's solution was infused into the right vertebral artery to cool the brain while maintaining the trunk temperature relatively warmer. When the brain temperature decreased to 20 degrees C or 25 degrees C, isoflurane administration was discontinued; the trunk temperatures at this stage were approximately 34.7 degrees C and 34.6 degrees C, respectively. After the end-tidal isoflurane concentration reached 0%, the base of the tail was stimulated with an electric current through 2 25-gauge needles. None of the dogs reacted to tail stimulation when the brain temperature was at 20 degrees C, whereas 7 of 8 reacted at 25 degrees C. These results indicate that selective brain hypothermia (20 degrees C) results in suppressing noxious-evoked movement in canines.

[Sixty percent lidocaine tape alleviates pain on injection of propofol after diminishing venipuncture pain]

We evaluated the efficacy of the 60% lidocaine tape in alleviating pain associated with intravenous propofol administration in 71 gynecological patients. Thirty-eight women had the tape applied for 2.5 h before venipuncture, with the remaining patients acting as the control. A 20 gauge cannula was inserted into the cephalic vein. Propofol at room temperature was injected at a rate of 1200 ml.hr-1. The statistical significance of differences was established with the Mann-Whitney's U test and the chi 2 test. The median level of pain intensity resulting from venipuncture among the patients treated with the tape was smaller than that in the control group (16.5, vs 34, P = 0.006). Thereafter, cannulation was successfully achieved with reduced or no pain (VAS at cannulation < or = 25, n = 39), and only 16% of the treatment group complained of pain on injection as compared with 53.8% of the control group (P = 0.02). Moreover, the pain intensity was decreased with lidocaine tape (P = 0.006). The cost of the lidocaine tape is covered by medical insurance for reducing pain on venipuncture. Thus, as the tape also alleviates the pain on injection of propofol through its anesthetic action, it can be a safe, easy and cost-effective method as "it kills two pains with one tape".

[The relief of postoperative pain by suppositories of buprenorphine or NSAID]

We evaluated the effects of suppositories of buprenorphine (BN) or NSAID (supp.) preoperatively administered for postoperative pain relief in patients who underwent elective gynecological surgeries. Fifty six patients were randomized into four groups: group B; 0.4 mg BN supp., group B+I; 0.4 mg BN supp. and 50 mg indomethacine (IND) supp., group B+D; 0.4 mg BN supp. and 50 mg diclofenac supp., group C; no supp. given as control. They were administered rectally after induction of general anesthesia. In all the supp. groups the patients had good pain relief during the first 24 hrs after the administration of supp. Group B+I seemed to have better pain relief, but, there was no statistical significance among the 3 groups. Nausea and vomiting were observed more frequently in group B and in control group C than in NSAIDs combined groups. The difference in the incidence rates was not significant. In conclusion, the simultaneous administration of BN and IND supp. was considered to be useful for postoperative pain relief without producing major side effects.

Effect of NMDA receptor antagonists on prostaglandin E2-induced hyperalgesia in conscious mice

Intrathecal (i.t.) injection of prostaglandin E2 (PGE2) to conscious mice produced a hyperalgesic action over a wide range of dosages with two apparent peaks at 100 pg and 10 ng per mouse, which may be mediated through EP3 and EP2 subtypes of the PGE receptor. In the present study, the effects of NMDA receptor antagonists on hyperalgesia induced by PGE2 were evaluated by the hot plate test at 30 min after i.t. injection. Hyperalgesia induced by a higher dose of PGE2 (10 ng/mouse) was relieved by D-AP5 (a competitive antagonist), 7-Cl-KynA (a glycine site antagonist), and ketamine and MK801 (non-competitive channel blockers). Intrathecal injection of butaprost (10 ng/mouse), an EP2 agonist, induced hyperalgesia, and this hyperalgesia was blocked by D-AP5, 7-Cl-KynA, ketamine, and MK801, similar to that induced by 10 ng of PGE2. On the other hand, hyperalgesia induced by a lower dose of PGE2 (100 pg/mouse) was blocked by D-AP5 and 7-Cl-KynA, but not by ketamine and MK801. Intrathecal injection of sulprostone (100 pg/mouse), an EP1 and EP3 agonist, induced hyperalgesia, and this hyperalgesia was blocked by D-AP5 and 7-Cl-KynA, but not by ketamine and MK801, similar to that induced by 100 pg of PGE2. These results first demonstrate that the NMDA receptor is involved in the PGE2-induced hyperalgesia and suggest that the hyperalgesic action by lower and higher doses of PGE2 may be mediated through EP3 and EP2 subtypes, respectively.

Characterization of EP-receptor subtypes involved in allodynia and hyperalgesia induced by intrathecal administration of prostaglandin E2 to mice

1. Intrathecal (i.t.) administration of prostaglandin E2 (PGE2) to conscious mice induced allodynia, a state of discomfort and pain evoked by innocuous tactile stimuli, and hyperalgesia as assessed by the hot plate test. We characterized prostaglandin E receptor subtypes (EP1-3) involved in these sensory disorders by use of 7 synthetic prostanoid analogues. 2. Sulprostone (EP1 < EP3) induced allodynia over a wide range of dosages from 50 pg to 5 micrograms kg-1. The maximal allodynic effect was observed at 5 min after i.t. injection, and the response gradually decreased over the experimental period of 50 min. This sulprostone-induced allodynia showed a time course similar to that induced by PGE2. 3. 17-Phenyl-omega-trinor PGE2 (EP1 > EP3) and 16,16-dimethyl PGE2 (EP1 = EP2 = EP3) were as potent as PGE2 in inducing allodynia, and more potent than sulprostone. Butaprost (EP2), 11-deoxy PGE1 (EP2 = EP3), MB 28767 (EP3), and cicaprost (prostaglandin I2 (IP-) receptor) induced allodynia, but with much lower scores. 13,14-Dihydro-15-keto PGE2, a metabolite of PGE2, did not induce allodynia. 4. 16,16-Dimethyl PGE2 as well as PGE2 induced hyperalgesia over a wide range of dosages (16,16-dimethyl PGE2: 5 pg-0.5 micrograms kg-1 PGE2: 50 pg-0.5 micrograms kg-1) with two apparent peaks at 0.5 ng kg-1 and 0.5 micrograms kg-1. Sulprostone (EP1 < EP3) and 17-phenyl-omega-trinor PGE2 (EP1 > EP3) showed a bell-shaped hyperalgesia at lower doses of 5 pg-5 ng kg-1 and 50 pg-50 ng kg-1, respectively. MB28767 (EP3)showed a monophasic hyperalgesic action over a wide range of dosages at 50 pg-S5 Microg kg-1. Butaprost(EP2) induced hyperalgesia at doses higher than 50 ng kg-1.5. These results demonstrate that PGE2 may exert allodynia through the EP1-receptor and hyperalgesia through EP2- and EP3-receptors in the mouse spinal cord.

Allodynia evoked by intrathecal administration of prostaglandin E2 to conscious mice

We recently reported that intrathecal (i.t) administration of prostaglandin (PG) F2 alpha to conscious mice induced allodynia that was elicited by non-noxious brushing of the flanks. In the presents study, we demonstrate that i.t. administration of PGD2 and PGE2 to conscious mice also results in allodynia. Dose dependency of PGD2 for allodynia showed a skewed bell-shaped pattern (0.1 ng-2.5 micrograms/mouse), and the maximal allodynic effect was observed with 1.0 microgram at 15 min after intrathecal injection. PGD2-induced allodynia showed a time course and dose dependency similar to that induced by PGF2 alpha, but with lower scores. On the other hand, dose dependency of PGE2 for allodynia showed a bell-shaped pattern over a wide range of dosage from 10 fg to 2.0 micrograms/mouse. The maximal allodynic effect was observed with 0.01-0.1 microgram at 5 min after i.t. injection, and the response gradually decreased over the experimental period of 50 min. Intrathecally administered strychnine and the GABAA antagonist bicuculline also induced allodynia in conscious mice. The time courses of allodynia evoked by strychnine and bicuculline coincided with those by PGE2 and PGF2 alpha, respectively. PGE2-induced allodynia was dose-dependently relieved by the strychnine-sensitive glycine receptor agonist taurine, the NMDA receptor antagonist ketamine, and a high dose of the alpha 2-adrenergic agonist clonidine, but not by the GABAA agonist muscimol or by the GABAB agonist baclofen. In contrast, PGF2-induced allodynia was dramatically inhibited by clonidine and baclofen, but not by taurine, ketamine or muscimol.(ABSTRACT TRUNCATED AT 250 WORDS)

Involvement of glutamate receptors in allodynia induced by prostaglandins E2 and F2 alpha injected into conscious mice

In order to investigate the involvement of glutamate receptor systems in allodynia induced by prostaglandin (PG) E2 or F2 alpha, we co-administered antagonists for N-methyl-D-aspartate (NMDA), non-NMDA, or metabotropic glutamate receptors intrathecally with PGE2 or PGF2 alpha and examined their effects on the allodynia evoked in conscious mice by non-noxious brushing of the flanks. MK-801, a non-competitive NMDA receptor channel blocker, and D-AP-5, a selective NMDA receptor antagonist, dose-dependently blocked PGE2-induced allodynia with an IC50 of 1.60 and 0.52 microgram/mouse, respectively. A glycine binding-site antagonist for the NMDA receptor, 7-Cl-KYNA, did not influence it. None of these NMDA receptor antagonists inhibited PGF2 alpha-evoked allodynia. Non-NMDA receptor antagonists GAMS and CNQX inhibited both PGE2- and PGF2 alpha-induced allodynia. On the other hand, L-AP-3 and L-AP-4, putative metabotropic glutamate receptor antagonists, dose-dependently antagonized the allodynia induced by PGF2 alpha with an IC50 of 0.92 and 3.26 ng/mouse, respectively, but not that induced by PGE2. Intrathecal administration of L-glutamate produced allodynia over a wide range of low doses from 0.1 pg to 0.1 microgram/mouse, and the maximal effect was observed at 1 ng. Similar to allodynia induced by prostaglandins, the response lasted over a 50-min experimental period. These results demonstrate that both PGE2- and PGF2 alpha-evoked allodynia are mediated through a pathway that includes the glutamate receptor system but that subtypes of glutamate receptors involved and sites of action in the spinal cord may be different between them.

Allodynia evoked by intrathecal administration of prostaglandin F2 alpha to conscious mice

The intrathecal administration of prostaglandin F2 alpha to conscious mice resulted in spontaneous agitation and touch-evoked agitation (allodynia) in the animals. The maximum allodynia induced by prostaglandin F2 alpha was observed at 10-15 min after intrathecal injection, and the response did not disappear by 120 min. Prostaglandin F2 alpha produced allodynia over a wide range of dosage from 0.1 pg to 2.5 micrograms/mouse. Dose dependency of prostaglandin F2 alpha for allodynia showed a skewed bell-shaped pattern, and the maximal allodynic effect was observed at 1.0 microgram. This allodynia was dose-dependently relieved by alpha 1-adrenergic (methoxamine), alpha 2-adrenergic (clonidine), and A1-adenosine (RPIA) agonists. Clonidine was 1.5 orders of magnitude more potent than methoxamine in blocking prostaglandin F2 alpha-induced allodynia. The blockade by clonidine was dose-dependently reversed by the alpha 2-adrenergic antagonist yohimbine but not by the alpha 1-adrenergic antagonist prazosin. These results demonstrate that prostaglandin F2 alpha administered intrathecally induces allodynia in conscious mice and that the allodynia involves the alpha 2-adrenergic and A1-adenosine systems. Because this allodynia has a clear resemblance to the characteristics of chronic pain in patients with causalgia and reflex sympathetic dystrophy, prostaglandin F2 alpha may be involved in allodynia observed with these disorders.

Nociceptive effects induced by intrathecal administration of prostaglandin D2, E2, or F2 alpha to conscious mice

The effects of intrathecal administration of prostaglandins on pain responses in conscious mice were evaluated by using hot plate and acetic acid writhing tests. Prostaglandin D2 (0.5-3 ng/mouse) had a hyperalgesic action on the response to a hot plate during a 3-60 min period after injection. Prostaglandin E2 showed a hyperalgesic effect at doses of 1 pg to 10 ng/mouse, but the effect lasted shorter (3-30 min) than that of prostaglandin D2. Similar results were obtained by acetic acid writhing tests. The hyperalgesic effect of prostaglandin D2 was blocked by simultaneous injection of a substance P antagonist (greater than or equal to 100 ng) but not by AH6809, a prostanoid EP1-receptor antagonist. Conversely, prostaglandin E2-induced hyperalgesia was blocked by AH6809 (greater than or equal to 500 ng) but not by the substance P antagonist. Prostaglandin F2 alpha had little effect on pain responses. These results demonstrate that both prostaglandin D2 and prostaglandin E2 exert hyperalgesia in the spinal cord, but in different ways.