Takanori Murayama

Effect of N -methyl-d-aspartate Receptor ε1Subunit Gene Disruption of the Action of General Anesthetic Drugs in Mice

Background:Recent molecular strategies demonstrated that the N-methyl-d-aspartate (NMDA) receptor is a major target site of anesthetic agents. In a previous article, the authors showed that knocking out the NMDA receptor &egr;1 subunit gene markedly reduced the hypnotic effect of ketamine in mice. In the current study, the authors examined the in vivo contribution of the NMDA receptor &egr;1 subunit to the action of other anesthetic drugs. Methods:The authors determined the anesthetic effects of nitrous oxide on sevoflurane potency in NMDA receptor &egr;1 subunit knockout mice compared with those in wild-type mice. They then tested the hypnotic effect of &ggr;-aminobutyric acid–mediated agents, such as propofol, pentobarbital, diazepam, and midazolam, in knockout mice and wild-type mice. Results:The anesthetic action of sevoflurane itself was unaffected by the abrogation of the NMDA receptor &egr;1 subunit. Adding nitrous oxide reduced the required concentration of sevoflurane to induce anesthesia in wild-type mice, whereas this sparing effect was diminished in knockout mice. Furthermore, propofol, pentobarbital, diazepam, and midazolam also had markedly attenuated effects in knockout mice. Conclusions:Although it has been demonstrated that knocking out the expression of receptors may induce changes in the composition of the subunits, the network circuitry, or both, the current findings show consistently that the NMDA receptor &egr;1 subunit mediates nitrous oxide but not sevoflurane anesthesia. Furthermore, the attenuated anesthetic impact of propofol, pentobarbital, diazepam, and midazolam as well as ketamine in knockout mice suggests that the NMDA receptor &egr;1 subunit could be indirectly involved in the hypnotic action of these drugs in vivo.

Arytenoid adduction combined with medialization laryngoplasty under general anesthesia using a laryngeal mask airway

PURPOSE Laryngeal framework surgery is usually performed under local anesthesia but cannot be tolerated by some patients. To develop a new procedure for these patients, we evaluated voice outcomes after arytenoid adduction combined with medialization laryngoplasty under general anesthesia using a laryngeal mask airway (LMA) for unilateral vocal cord paralysis. MATERIALS AND METHODS Eleven consecutive patients with severe unilateral vocal cord paralysis, with a maximum phonation time of less than 5 seconds, underwent arytenoid adduction combined with medialization laryngoplasty under general anesthesia using an LMA. Each paralyzed vocal cord was observed by intraoperative videolaryngoscopy. The vocal cord was moved to the position where the best vocal outcome could be expected, according to 3 parameters obtained from glottal images. RESULTS All patients achieved a maximum phonation time of more than 11 seconds. The mean airflow rate, which ranged from 550 to 1000 mL/s before surgery, improved to less than 390 mL/s. Perceptual evaluation using the grade, roughness, breathiness, asthenia and strain scale also improved significantly. CONCLUSIONS These results were equivalent to those of previous reports of surgeries performed under local anesthesia. Intraoperative endoscopic vocal cord observation through the LMA may have contributed to the positive results.

Effects of low-dose atrial natriuretic peptide infusion on cardiac surgery–associated acute kidney injury: A multicenter randomized controlled trial

Purpose: To evaluate the effects of atrial natriuretic peptide (ANP) on renal function and medical costs in patients with acute kidney injury (AKI) associated with cardiac surgery. Materials and methods: The Japanese trial for AKI in Post‐cardiovascular surgery patients by ANP (JAPAN) was a prospective, multicenter, randomized, double‐blind, placebo‐controlled study conducted in 11 hospitals in Japan. Acute kidney injury was defined as an increase in serum creatinine of at least 0.3 mg/dL within 48 hours. The patients were randomly assigned to receive ANP (0.02 &mgr;g kg−1 min−1) or placebo. The primary end point was a change in renal function. The secondary end points were a need for renal replacement therapy, the lengths of intensive care unit and hospital stays, and medical costs incurred over the 90‐day follow‐up. Results: Of the 77 randomized patients, 37 were in the ANP group and 40 were in the placebo group. Although ANP significantly (P = .018) increased urine output, it did not significantly improve renal function compared with placebo. There were no significant differences between the groups in the renal replacement therapy rate, the lengths of the intensive care unit and hospital stays, or medical costs. Conclusion: Atrial natriuretic peptide infusion did not show a renoprotective effect or cost‐saving effect in the treatment of cardiac surgery–associated AKI. HighlightsANP was administered in patients with AKI associated with cardiac surgery.ANP significantly increased urine output.ANP did not significantly improve renal function.ANP did not significantly reduce the renal replacement therapy rate or medical costs.

Epidural spinal cord stimulation for neurogenic bladder.

Epidural spinal cord stimulation (ESCS) with a percutaneously inserted catheter electrode has produced symptomatic relief of deafferentation pain and vasculopathic pain as well as pain produced by spinal cord trauma, damage to nerve roots or peripheral nerves, and failed back surgery. Other applications of ESCS include urinary incontinence and occipital neuralgia [1]. We present a case in which ESCS was used successfully for the treatment of a neurogenic bladder.

Dislocation of a detached electrode from a pacing Swan–Ganz catheter in the hepatic vasculature

To the Editor: The pacing pulmonary artery catheter (PAC) is very efficacious in some cases, but it can be associated with a rare complication specifically associated with its placement. Here we describe the case of an electrode that became detached from the pacing PAC, only to be visualized later in the liver of the patient on the postoperative computed tomography (CT) images. An 80-year-old, 35-kg woman presented for valve replacement for aortic stenosis, mitral regurgitation and annuloplasty for tricuspid regurgitation. Under general anesthesia, the right internal jugular vein (RIJV) of the patient was cannulated with a central venous catheter (8.5French AVA 3Xi multi-lumen sheath introducer catheter; Edwards Lifesciences, Irvine, CA) with two infusion lumens and an introducer. A pacing PAC (model D205HF7; Edwards Lifesciences), which had five built-in electrodes integrated for atrial and/or ventricular pacing, was inserted through the introducer. Repeated attempts to advance the PAC blindly failed. When the operator withdrew the PAC through the introducer, he felt light resistance and shortly thereafter noticed that the second electrode from the top for ventricular pacing was missing from the PAC (Fig. 1a, b). The introducer was immediately examined to determine the cause(s) of the detachment, but no cause was identified. A second pacing PAC was inserted again through the introducer from the RIJV under mobile C-arm fluoroscopic guidance. Thereafter the patient successfully underwent the surgical procedure. The patient had an uneventful postoperative course, and subsequent CT imaging revealed that the metallic tip of the first pacing PAC was in the posterior region of the hepatic right lobe (Fig. 1c). The patient did not suffer from liver dysfunction during the postoperative course, and liver function has remained normal . The electrode consists of elgiloy alloy (Co–Cr–Ni alloy) that is characterized by its high strength, ductility, corrosion resistance and excellent fatigue life over a wide temperature range. It is used widely to construct clips for cerebrovascular aneurysms, carotid arterial stents, among others. The dimensions of the electrode are 2 9 2 mm. At the time of detachment, catheter intervention would have been almost impossible because the electrode was caught in a fragment of the vein that was too small. We therefore chose medical observation and would have, if necessary, performed hepatectomy with its associated surgical risk. A literature search of the PubMed databases revealed only two case reports comparable to our case [1, 2]. In these two reported cases, the three detached electrodes that remained in the body had gone into the pulmonary vasculature; in one case report, two electrodes were retrieved from within the introducer. In our case, the fragment was H. Aoyama (&) Y. Otsuka K. Asaka T. Murayama Department of Anesthesiology and Critical Care Medicine, Jichi Medical University, Saitama Medical Center, Amanuma-cho 1-847, Omiya-ku, Saitama 330-8503, Japan e-mail: h.aoyama@omiya.jichi.ac.jp

Syncope after therapeutic caudal epidural block: report of two cases.

an L1 level sensory block was achieved 30 min after the injection. The second patient was a 77-year-old woman (152 cm, 43 kg) who, at her initial visit to our clinic, had complaints of lumbago and melalgia. Her medical history was unremarkable except for osteoporosis and severe diffuse spondylosis. A caudal epidural block was performed, with the patient in the left lateral decubitus position. Anatomical landmarks were easily identified, and 20 ml of 0.5% mepivacaine, mixed with 125 mg methylprednisolone was injected through the sacral hiatus with a 3.2-cm 22-gauge needle. As soon as the injection was completed, the patient complained of headache and nausea. Within 2 min, the patient became unconscious, and hypertensive (systolic blood pressure was 220mmHg), and showed bradycardia (60 bpm). A few minutes later, her mental status improved, and she was taken to have brain computed tomography (CT). No convulsion was noted throughout this syncopal episode, and an adequate sensory block was achieved. The brain CT was negative. Both patients were discharged home without any sequelae after a 2-h stay in the recovery unit. A few cases of syncopal episodes after caudal epidural injections have been reported in the past [7,9]. In one report [9], a huge volume (60 ml) was injected into the epidural space, while in another [10], the patients had brain tumors and increased ICP. In old patients with spondylosis, the escape routes from the epidural space are considerably narrow, and the epidural compliance is considered to be low [2,5]. Although the injection volume in our practice was modest, there is no doubt that our technique triggered the transient syncopal attacks in the present two patients with severe spondylosis. Therefore, one could assume that the injection into the lowcompliant extradural space triggered an increase in ICP, a decrease in CBF, and the altered mental status. In future practice, the speed and volume of caudal epidural injections should be specifically tailored for older patients with severe spondylosis.

Relationship between symptoms of ischemic heart disease and upper abdominal digestive organ disease.

We previously reported that percutaneous trans-arterial coronary angioplasty (PTCA) seemed to decrease cardiac complications in patients with ischemic heart disease (IHD) who underwent abdominal surgery. After the report, 1293 PTCAs were performed for patients with IHD in our institute. Of these 1293 patients, 6 patients underwent abdominal surgery under general anesthesia within 14–150 days after successful PTCA. We observed the relationship between symptoms of IHD and upper abdominal digestive organ disease (ADOD), which sometimes occurs concomitantly in IHD patients. In conclusion, the present study identified some features of the chief complaints and symptoms of IHD patients with concomitant upper ADOD. This information should prove useful for making a differential diagnosis and deciding treatment.

Diagnostic value of bronchoalveolar lavage in fat embolism syndrome: Report of a case

Fat embolism syndrome is a rare disorder that is commonly associated with traumatic fractures of the long bones and/or pelvis. Gurds criteria have been widely used in diagnosis, and several other criteria have been advocated [l-3]. All of these criteria are based on nonspecific clinical and biochemical features. Recently, fat staining of cells recovered by bronchoalveolar lavage has been introduced as a rapid and specific diagnostic method [4]. We present a case of fat embolism syndrome in which bronchoalveolar lavage and fiberoptic bronchoscopy were performed early in the patients clinical course.