Shinichiro Miyazaki

Muscle relaxant effects on insertion efficacy of the laryngeal mask ProSeal® in anesthetized patients: a prospective randomized controlled trial

BackgroundAnesthesiologists often encounter LMA-ProSeal® (ProSeal) insertion difficulty due to its large cuff size. We performed a randomized clinical trial to examine how insertion efficacy and sealing pressure of ProSeal are affected by muscle relaxant administration in anesthetized patients.MethodsOur adult patients were either administered rocuronium (0.9xa0mgxa0kg−1) as a muscle relaxant (R group; 40 patients) or not (C group; 40 patients). Anesthesia was induced with propofol and fentanyl. We compared the two groups with regard to the number of attempts required for successful insertion, sealing pressure, and subjective difficulty for insertion.ResultsTotal insertion attempts required for successful ventilation in the two groups were one (R group, 38 patients; C group, 28 patients), two (R group, one patient; C group, seven patients), and three (R group, one patient; C group, five patients), revealing a significant difference between groups (pxa0<xa00.001). Sealing pressure was significantly higher in the R group than in the C group (R group, 27.4xa0±xa05.4xa0cmH2O; C group, 21.2xa0±xa05.2xa0cmH2O; pxa0<xa00.001). Leakage volume by mechanical ventilation was significantly smaller in the R group than in the C group (R group, 17.4xa0±xa029.1xa0ml; C group, 46.8xa0±xa045.5xa0ml; pxa0<xa00.001). Subjective difficulty of insertion was significantly lower in the R group than in the C group (R group, 12.3xa0±xa023.1xa0mm; C group, 39.4xa0±xa031.9xa0mm; pxa0<xa00.001).ConclusionsMuscle relaxation appears to facilitate ProSeal insertion efficacy by enabling higher successful insertion rates, higher sealing pressure, lower leakage volume, and lower subjective difficulty of insertion in anesthetized patients.

SHIFTS IN ENDOTRACHEAL TUBE POSITION DUE TO CHEST COMPRESSIONS: A SIMULATION COMPARISON BY FIXATION METHOD

BACKGROUNDnEndotracheal tube placement during resuscitation is important for definite tracheal protection. Accidental extubation due to endotracheal tube displacement is a rare event that can result in severe complications.nnnOBJECTIVEnThis study evaluated how endotracheal tube displacement is affected by tape vs. tube holder fixation using a manikin and auto-chest compression machine simulation.nnnMETHODSnThe endotracheal tube was placed in either a shallow or a deep position, with the tube cuff at the center of the glottis or 26 cm from the incisors in an advanced lifesaving simulator. Trials were performed five times in each setting with: no fixation; Durapore® tape fixation; Multipore® tape fixation; and Thomas tube holder® fixation. After 10 min of automated chest compressions, endotracheal tube shift was measured. Statistical analysis was performed with one-way repeated analysis of variance or χ(2) test, with p < 0.05 considered significant.nnnRESULTSnIn the shallow setting, endotracheal tube extubation occurred in all trials with no fixation, Durapore, and Multipore. In contrast, no extubation occurred in the Tube holder trials (p < 0.05). In the deep setting, no extubation was confirmed in any trial. Relative to no fixation (0.56 ± 0.11 cm), endotracheal tube shift was significantly less in the Durapore tape, Multipore tape, and Tube holder groups (p < 0.05). Of the three fixation methods, Tube holder (0.04 ± 0.05 cm) showed significantly less shift (p < 0.05) relative to Durapore (0.28 ± 0.04 cm) and Multipore (0.32 ± 0.08 cm).nnnCONCLUSIONnEndotracheal tube displacement occurs less with Tube holder fixation than with Durapore tape or Multipore tape during simulation of continuous chest compressions.

Comparison of fluid leakage from four different cuffed pediatric endotracheal tubes using a pediatric airway simulation model.

This study used an airway model to compare the ability of a pediatric endotracheal tube with a taper‐shaped cuff to prevent microaspiration relative to endotracheal tubes with conventional cuffs. Four different types of 5.0‐mm inner diameter cuffed pediatric endotracheal tubes (taper‐shaped cuff [Taper], high‐volume low‐pressure [Hi‐Lo], middle‐volume low‐pressure [Intermediate], and low‐volume low‐profile [Lo‐Pro]) were fixed within vertically placed acrylic tubes. The cuffs were maintained at 10, 20, or 30 cmH2O pressure and 3u2009mL of simulated stomach contents was added to the top of the cuffs. The volume of leakage around the cuffs after 5u2009min and 4u2009h was measured. After 5u2009min, the volume of leakage was significantly lower with the Taper than with the Hi‐Lo, Intermediate, or Lo‐Pro at all pressure settings. After 4u2009h, leakage was significantly lower with the Taper than with the other three tubes regardless of initial cuff pressure (P < 0.05).

Proteomic analysis of cerebrospinal fluid before and after intrathecal injection of steroid into patients with postherpetic pain.

Postherpetic neuralgia (PHN) is the most frequent complication of herpes zoster, and the risk of it increases with age. By comparing proteomes of the cerebrospinal fluid (CSF) before and after the treatment, it may be possible to identify proteins that play a role in PHN and to predict responses to various treatments. To address this issue, we enrolled eight outpatients with PHN over 55 years of age and treated them with intrathecal methylprednisolone and lidocaine four times every week, collecting CSF samples before the treatment at each visit. We used 2D DIGE to investigate differentially expressed proteins in the CSF before and after repetitive treatments individually. Of 145 differentially expressed spots, the levels of nine proteins were decreased by the treatment including lipocalin‐type prostaglandin D synthase (L‐PGDS), and five were increased by it. The time course of alterations in the L‐PGDS concentration in the CSF of each patient, detected by a pairwise and sandwich ELISA by SPR constructed here was well correlated with that by 1DE Western blots with anti‐L‐PGDS antibody, but was not related with that of the pain relief. The present study demonstrates that the real‐time ELISA was precise and sensitive enough to measure L‐PGDS in the CSF and that the steroid treatment decreased the L‐PGDS concentration in CSF.

The action site of the synthetic kainoid (2S,3R,4R)-3-carboxymethyl-4-(4-methylphenylthio)pyrrolidine-2-carboxylic acid (PSPA-4), an analogue of Japanese mushroom poison acromelic acid, for allodynia (tactile pain).

We previously demonstrated that intrathecal (i.t.) administration of acromelic acid A (Acro-A) induced allodynia in mice and that simultaneous administration of (2S,3R,4R)-3-carboxymethyl-4-(phenylthio)pyrrolidine-2-carboxylic acid (PSPA-1), an Acro-A analogue, attenuated the Acro-A-induced allodynia. To clarify a mechanism of PSPA-1, we attached methyl radical to PSPA-1 and synthesized (2S,3R,4R)-3-carboxymethyl-4-(4-methylphenylthio) pyrrolidine-2-carboxylic acid (PSPA-4) and [(11)C]PSPA-4 for behavioral and autoradiography studies. Although PSPA-4 inhibited the Acro-A-induced allodynia in a dose-dependent manner from 1 to 10 fg/mouse, PSPA-4 itself induced allodynia at 10 to 100 pg/mouse. In vitro autoradiography, [(11)C]PSPA-4 was specifically bound to the rat brain and spinal cord, and the binding was significantly displaced by PSPA-1 and kainic acid, but not by AMPA and antagonists of NMDA, AMPA and kainate receptors. Conversely, [(3)H]kainate was specifically bound to the rat brain and the dorsal horn of spinal cord, and the binding was significantly displaced by PSPA-1 and PSPA-4. The PSPA-4-induced allodynia was blocked by the AMPA/kainate antagonist GYKI53655, but not by kainate antagonists NS102 and UBP296. PSPA-4 increased intracellular Ca(2+) concentration in 27.9% of cultured dorsal root ganglion neurons responding to glutamate, much higher than kainate in 10.9% of them. Taken together, these results suggest that PSPA-4 attenuated the Acro-A-induced allodynia at low doses and induced allodynia at high doses via a binding site different from known kainate antagonists. The development of a radio-labeled PSPA-4 will enable us to promote the understanding of the action mechanism not only of Acro-A, but also of pain transmission in the periphery and central nervous system.

Cerebrospinal fluid of postherpetic neuralgia patients induced interleukin-6 release in human glial cell-line T98G

Chronic intractable pain caused by postherpetic neuralgia (PHN) can be alleviated by intrathecal (i.t.) steroid therapy. We investigated the possibility that interleukin-6 (IL-6) release in an in vitro system could be a potential marker for evaluating the effectiveness of i.t. steroid therapy in PHN patients. We studied 32 patients who received a course of i.t. injection of water-soluble dexamethasone. Their therapeutic index was calculated as such: ((Pain score before treatment - Pain score after treatment)÷Pain score before treatment)×100%, and they were divided into two groups, therapy effective (index>50%) and ineffective (index<50%). Cerebrospinal fluid (CSF) from the patients was used to stimulate cultures of T98G glioblastoma cells, and the subsequent IL-6 release was measured by enzyme-linked immunosorbent assay (ELISA). Our results showed that the CSF triggered IL-6 release from T98G cells in a volume-dependent manner. IL-6 release was significantly lower when using CSF from the therapy effective patient group (p<0.001) compared to the therapy ineffective group. In particular, therapy effective patients had less IL-6 release even before treatment as compared to therapy ineffective patients. In the therapy effective group, in vitro steroid treatment suppressed the CSFs IL-6 releasing effect almost completely, whereas in the therapy ineffective group, the IL-6 release was significantly reduced but remained detectable. These in vitro tests may provide an objective evaluation on the efficacy of i.t. steroid therapy administered to PHN patients.

Comparison of mechanisms of allodynia induced by acromelic acid A between early and late phases

We previously showed that intrathecal administration of acromelic acid A (ACRO-A) provoked tactile allodynia in mice. As well, recent studies have demonstrated that the activation of NMDA glutamate receptor-neuronal nitric oxide synthase (nNOS) pathway and glia play crucial roles in the development and maintenance of neuropathic pain. In order to clarify their involvement in ACRO-A-induced allodynia, we investigated the effects of various agents on two mouse models at early and late-phase allodynia. The agents employed were Ca(2+) channel α2δ ligands, NMDA and AMPA receptor antagonists, nNOS, and Ca(2+)/calmodulin kinase II inhibitors. When injected simultaneously with ACRO-A, all of these agents blocked allodynia in the early-phase group; however, they did not block allodynia when injected 7 days after the administration of ACRO-A in the late-phase group. In order to block glial activation, astrocytic inhibitor L-α-aminoadipate (LAA) or microglial inhibitor minocycline was administrated, and allodynia was examined on day 7. Activations of nNOS and glia in the spinal cord were histochemically examined at 1 h or 1 week after injection of ACRO-A. We found that nNOS activity increased 1 h after ACRO-A injection; however, it did not increase 1 week after ACRO-A injection. Conversely, microglial activation was observed 1 week after ACRO-A injection and was significantly inhibited with minocycline treatment. Moreover, only LAA was found to inhibit late-phase allodynia. In this study, we demonstrate that NMDA receptor activation is involved only in ACRO-A-induced tactile allodynia in the early phase, and that spinal astrocytic activation contributes to allodynia in the late phase.

Intraoperative transesophageal echocardiography enables characterization of coronary artery fistula in coexistence with multiple giant coronary artery aneurysms.

A 35-yr-old healthy woman was admitted for evaluation of an abnormal cardiac mass on twodimensional transthoracic echocardiography (TTE). TTE demonstrated an abnormal giant mass dorsad to the right atrium and right ventricle. Although color Doppler TTE revealed abnormal blood flow within the left atrium (LA), the mass was not well visualized. Coronary angiography revealed a normal left coronary artery and an 80-mm internal diameter (ID) aneurysm at the proximal portion of right coronary artery (RCA). The giant aneurysm did not allow the distal part of RCA to be visualized. Meanwhile, threedimensional computed tomography (3-D CT) revealed three giant coronary artery aneurysms (CAAs) (Fig. 1). To avoid the risk of aneurysm rupture, surgery was planned.

Aortic Papillary Fibroelastoma Detected by Transesophageal Echocardiography

We report a case of papillary fibroelastoma (PFE) detected by transesophageal echocardiography (TEE) that was not pointed out preoperatively by transthoracic echocardiography (TTE). A 59-year-old woman underwent open mitral commissurotomy for mitral stenosis in 1979. In 2005, she complained of exertional dyspnea, and follow-up TTE showed mitral valve restenosis and tricuspid regurgitation. In the laboratory findings on admission, the complete blood count showed no abnormalities, and the C-reactive protein was normal. Then, mitral valve replacement was performed. During the operation, TEE showed severe mitral stenosis, moderate tricuspid regurgitation, and a mobile mass of the aortic valve. In the midesophageal aortic valve long-axis view, a mobile pediculate tumor with a homogenous echodense mass (diameter approximately 6 mm) could be seen and was attached to the right coronary cusp of the aortic valve (Fig 1). The movement of the aortic valve was normal. The resection of the tumor was performed without aortic valve replacement, and the histopathologic diagnosis was PFE (Fig 2).