K-H Chen

Chang Gung Memorial Hospital, Taipei, Taipei, Taiwan

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Publications (6)9.84 Total impact

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    ABSTRACT: Tolerance to the analgesic effect of opioids complicates the management of persistent pain states. We tested whether the intrathecal infusion of small interfering RNA (siRNA) against β-arrestin 2 would reduce tolerance to chronic morphine use and the severity of precipitated morphine withdrawal. Intrathecal β-arrestin 2 (2 μg siRNA per 10 μl per rat) was injected once daily for 3 days. Rats then received a continuous intrathecal infusion of morphine (2 nmol h⁻¹) or saline for 7 days. Daily tail-flick (TF) and intrathecal morphine challenge tests were performed to assess the effect of intrathecal β-arrestin 2 siRNA on antinociception and tolerance to morphine. Naloxone withdrawal (2 mg kg⁻¹) was performed to assess morphine dependence. In the daily TF test, the antinociception of intrathecal morphine was increased and maintained in rats receiving β-arrestin 2 siRNA compared with the control group (morphine alone). In the probe response test, rats receiving morphine infusion with β-arrestin 2 siRNA treatment showed a significant left shift in their dose-response curve, as measured by per cent maximal possible effect (MPE), such that the AD₅₀ was significantly decreased by a factor of 5.6 when compared with that of morphine-infused rats. In the naloxone-induced withdrawal tests, rats receiving β-arrestin 2 siRNA injection with morphine infusion showed a significant reduction in four of the six signs of withdrawal. We show here that intrathecal β-arrestin 2 siRNA in rats enhances analgesia and attenuates naloxone-induced withdrawal symptoms. This may warrant further investigation in the context of long-term use of intrathecal opioids for controlling chronic pain.
    BJA British Journal of Anaesthesia 09/2011; 107(5):774-81. · 4.24 Impact Factor
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    ABSTRACT: Dantrolene is the drug of choice in treatment of malignant hyperthermia. However, dantrolene is hepatotoxic; thus prolonged use is not recommended in patients with active hepatic disease such as acute hepatitis or active cirrhosis because it may result in fatal hepatic failure. Use of dantrolene in a patient with end-stage liver disease undergoing liver transplantation (LTx) in whom suspected malignant hyperthermia developed has been reported rarely. Its effect on the liver allograft, which has sustained cold, warm, and reperfusion injuries, is currently unknown. We report a case in which low-dose dantrolene administered intravenously during LTx was effective in treating hyperthermia, hypercapnia, and hyperkalemia. Furthermore, its reported hepatotoxic effect seemed to not affect recovery of the allograft after LTx.
    Transplantation Proceedings 04/2010; 42(3):858-60. · 0.95 Impact Factor
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    ABSTRACT: Our aim was to present the case of a pediatric biliary atresia patient who experienced rhabdomyolysis with severe cardiac arrhythmias associated with hyperkalemia, metabolic acidosis, and myoglobulinemia during liver transplantation. A 5-year-old girl, weighing 16.5 kg, with end-stage liver disease due to biliary atresia underwent living donor liver transplantation. A sudden onset of atrial fibrillation with rapid ventricular response was noted during the transplantation. The cardiac arrhythmia was associated with hyperkalemia, metabolic acidosis, and myoglobulinemia. Rhabdomyolysis was suspected. Hyperkalemia and metabolic acidosis were not corrected despite treatment with 10 mL of 50% glucose plus 6 U of regular insulin in 4 succeeding boluses and 110 mEq sodium bicarbonate before sending the patient to the intensive care unit. A corresponding decrease and normalization in serum potassium and correction of metabolic acidosis were noted as responses to a single dose of intravenous (20 mg) dantrolene. The patient was extubated 5 days after transplantation. The kidney function remained within normal limits during the rhabdomyolysis and the entire hospital stay. The patient was discharged 7 weeks later and is surviving with the original liver graft and satisfactory kidney function to date.
    Transplantation Proceedings 11/2008; 40(8):2821-2. · 0.95 Impact Factor
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    ABSTRACT: We describe the anesthetic management in a 56-year old man with hepatocellular carcinoma and cirrhosis who underwent liver transplantation (LT). Pretransplantation workup showed a 3-cm wide by 10-cm long infrarenal abdominal aortic aneurysm (AAA) with chronic dissection. He subsequently underwent living donor LT. The total operative time was 12 hours. The systolic blood pressure was maintained at normal levels. Severe hypertension was not noted. Hypotension noted during the anhepatic phase was managed with increased volume infusion and small doses (0.1 mg) of intravenous phenylephrine. Metabolic acidosis and ionized hypocalcemia were corrected accordingly. Total blood loss was 460 mL. Blood or blood products were not given. The intravascular volume was replaced with 1400 mL of 5% albumin and 10,610 mL of crystalloid. Extubation was performed in the intensive care unit at 12 hours after the operation. The postoperative course was unremarkable. The patient is alive at 3 years after LT. Patients with AAA undergoing LT present a challenge to the anesthesiologist because among the risk factors for rupture, blood pressure is the only factor under his or her control during the operation. If blood loss can be kept to a minimum and hemodynamic stability achieved, a chronically small dissected AAA may not be a contraindication to LT.
    Transplantation Proceedings 11/2008; 40(8):2830-1. · 0.95 Impact Factor
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    ABSTRACT: The aims of the study were to determine the effects of denervation on the function of the liver transplantation as a blood reservoir and to define its vulnerability to ischemic-reperfusion (I/R) injury after hemorrhagic shock. Hemorrhagic shock with a mean arterial blood pressure (MAP) of 40 to 50 mm Hg was induced by withdrawing blood at a rate of approximately 1 mL/min among 10 posttransplant denervated rats and 10 sham rats for 1 hour. The rats were then resuscitated by retransfusing the drawn blood with sacrifice under deep anesthesia at 1 hour after resuscitation. The total amount of blood required to achieve hemorrhagic shock was compared between groups as well as the vulnerability and reactions of the posttransplant denervated liver to I/R injury after hemorrhagic shock as assessed by gene expressions of c-jun, c-fos, tumor necrosis factor (TNF)-alpha, interleukin (IL)6, IL-10, and heat-shock protein 70 (HSP70). The volume of blood that had to be drawn to reach a MAP of 40 to 50 mm Hg was not significantly different between the groups. One hour of hemorrhagic shock followed by resuscitation resulted in significant increases in the genes expression of c-fos, TNF-alpha, IL-6, IL-10, and HSP70 in comparison to the control values, but no difference was observed between experimental and sham groups. We suggest that the function of the liver as a blood reservoir and the gene expressions of c-fos and pro- and anti-inflammatory cytokines, as well as the protective protein HSP70 in response to I/R injury, were not altered by liver transplantation.
    Transplantation Proceedings 10/2008; 40(7):2175-7. · 0.95 Impact Factor
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    ABSTRACT: Pregnancy is often considered a contraindication to living related liver donation. There are serious medical and ethical considerations if a pregnant woman insists on undergoing partial hepatectomy to save her sick child. Herein we report a case of living related liver donation from a pregnant woman at 18 weeks of gestation to her 1-year-old child with decompensated cirrhosis due to biliary atresia. The left lateral segment of the liver was harvested for donation. Meticulous surgical technique and anesthetic management were mandatory in assuring a successful outcome. While this isolated case demonstrated that living related liver donation can be performed successfully with a pregnant donor, it should be undertaken only when there is absolutely no other donor and the recipient is in urgent need.
    International Journal of Obstetric Anesthesia 05/2006; 15(2):149-51. · 1.80 Impact Factor