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.

The influence of head and neck position on ventilation with the i-gel airway in paralysed, anaesthetised patients.

CONTEXT AND OBJECTIVE: We hypothesised that head and neck position could affect the effectiveness of ventilation with the i-gel airway. To test this hypothesis, we investigated the influence of different head and neck positions on oropharyngeal sealing pressures and ventilation scores during ventilation with i-gel. METHODS: A single, experienced supraglottic airway device user inserted the i-gel in 20 paralysed, anaesthetised patients who were scheduled for oral surgery. Oropharyngeal leak pressures and ventilation scores were measured with the head and neck in the neutral position, flexed, extended or rotated to the right. Ventilation was scored from 0 to 3 based on three criteria (no leakage with an airway pressure of 15 cmH2O, bilateral chest excursion and a square wave capnogram; each item scoring 0 or 1 point). RESULTS: Compared with the neutral position (25.8 ± 5.2 cmH2O), oropharyngeal leak pressure was significantly higher with flexion (28.5 ± 3.4 cmH2O, P=0.015) and lower with extension (23.0 ± 4.2 cmH2O, P=0.015), but similar with rotation (26.7 ± 5.1 cmH2O, P=0.667). Flexion of the head and neck [2 (1-3)] adversely affected the ventilation score compared with the neutral position [3 (2-3), P=0.004]. CONCLUSION: Effective ventilation with an i-gel can be performed in patients in whom the head and neck is extended or rotated, whereas flexion of the head and neck adversely affects ventilation. Clinically, flexion of the head and neck should be avoided during ventilation with the i-gel.

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.

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.