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ABSTRACT: More than 50% of amputees report experiencing significant stump or phantom pain. Stump pain is often attributed to the formation of a neuroma at the amputation site. Experimental evidence shows that catecholamines and alpha-adrenoceptors play a role in the mechanisms of pain associated with neuromas. We investigated whether administration of physiological doses of norepinephrine (NE) in the distal stump in the region of a probable neuroma evoked pain and if local administration of phentolamine attenuated NE-evoked pain in patients with postamputation stump pain.
Twenty patients with postamputation stump pain participated in the study. In 15 patients, 0.2 mL of saline and NE (10(-7), 10(-6), and 10(-5) molar concentrations) were administered sequentially in a single blinded fashion in the region of maximal tenderness and Tinel sign, a probable site of a neuroma. In 12 of these 15 patients, pain evoked by 0.2 mL of 10(-5) M NE was examined before and after the injection of 0.2 mL phentolamine 10(-4) M. Patients rated their pain using a computer-based visual analog scale. The area under the curve was calculated for pain evoked by each injection and the scores were normalized to the first saline injection.
The perineuronal administration of NE had a dose-dependent increase in pain (P=0.005). In contrast, repeated saline injections did not result in increased evoked pain. There was a partial reversal of the pain evoked by 10(-5) M NE after pretreatment with phentolamine (NE 10(-5) M prephentolamine versus normal saline P=0.02, NE 10(-5) M postphentolamine versus normal saline P=0.054).
Our data suggest that alpha-adrenoceptor mechanisms contribute to stump pain, possibly associated with neuromas in amputees. Sympathectomy and adrenergic blockade should be explored in controlled clinical trials as therapeutic options in patients with postamputation pain.
Clinical Journal of Pain 07/2006; 22(5):482-6. · 2.81 Impact Factor
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ABSTRACT: The authors performed a meta-analysis and found that epidural analgesia overall provided superior postoperative analgesia compared with intravenous patient-controlled analgesia. For all types of surgery and pain assessments, all forms of epidural analgesia (both continuous epidural infusion and patient-controlled epidural analgesia) provided significantly superior postoperative analgesia compared with intravenous patient-controlled analgesia, with the exception of hydrophilic opioid-only epidural regimens. Continuous epidural infusion provided statistically significantly superior analgesia versus patient-controlled epidural analgesia for overall pain, pain at rest, and pain with activity; however, patients receiving continuous epidural infusion had a significantly higher incidence of nausea-vomiting and motor block but lower incidence of pruritus. In summary, almost without exception, epidural analgesia, regardless of analgesic agent, epidural regimen, and type and time of pain assessment, provided superior postoperative analgesia compared to intravenous patient-controlled analgesia.
Anesthesiology 12/2005; 103(5):1079-88; quiz 1109-10. · 5.36 Impact Factor
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Haematologica 05/2005; 90(4):441-4. · 6.42 Impact Factor
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ABSTRACT: Pulmonary hypertension is one of the leading causes of death in adult sickle cell patients, with a prevalence of 20% to 40%. Although these patients have lower pulmonary pressures than patients with primary pulmonary hypertension, both groups suffer high 2-year mortality rates. Pulmonary hypertension may go undetected until the disease is advanced. Therefore, all adult patients with sickle cell disease should be screened with transthoracic Doppler echocardiogram and the tricuspid regurgitant jet (TRJ) velocity measured to estimate pulmonary artery pressures. A regurgitant jet (RJ) velocity of 2.5 m/s or higher establishes diagnosis and suggests a high risk of death (rate ratio of 10.1; CI= 2.2-47). Basic and epidemiologic studies suggest that pulmonary hypertension in sickle cell disease is mechanistically linked to chronic hemolytic anemia. Hemolysis results in the release of hemoglobin and arginase from the erythrocyte, increasing the consumption and decreasing the production of nitric oxide (NO), respectively. NO is a critical regulator of vasodilation and vascular homeostasis whose inactivation produces vasoconstriction and proliferative vasculopathy. Finally, we review suggested therapies including the established treatments and new pulmonary vasodilator and remodeling agents in the management of pulmonary hypertension in hemolytic anemias.
Current hematology reports 04/2005; 4(2):117-25.
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ABSTRACT: Although the addition of a background infusion for intravenous patient-controlled analgesia (IV-PCA) has been identified as a risk factor for the development of respiratory depression, this has not clearly been examined in a systematic fashion. The authors undertook a systematic review and meta-analysis of available randomized controlled trials (RCTs) to examine whether the addition of a background or continuous infusion to an IV-PCA regimen would be associated with an increased risk of respiratory depression.
Studies were identified by searching the National Library of Medicine's PubMed database (1966 to November 30, 2008). Inclusion criteria were a clearly defined analgesic technique of demand-only IV-PCA versus IV-PCA utilizing both a demand dose and background infusion, opioid medication used, and randomized trials. Data were abstracted and analyzed with the RevMan 4.2.7 (The Cochrane Collaboration, 2004).
The search yielded 687 abstracts from which the original articles were obtained and data abstracted with a total of 14 articles analyzed. There were 402 subjects in the continuous IV-PCA with demand group versus the 394 subjects in the demand-only IV-PCA group. Addition of a background infusion to the demand dose for IV-PCA with opioids was associated with a significant increased risk for respiratory depression (odds ratio [OR] = 4.68, 95% confidence interval [CI]: 1.20-18.21). Subgroup analysis revealed that this increased risk was seen in adult but not in pediatric patients.
Our meta-analysis indicates that the addition of a continuous or background infusion to the demand dose for IV-PCA is associated with a higher incidence of respiratory events than demand IV-PCA alone in adult but not in pediatric patients; however, our overall results should be interpreted with caution due to the relatively small sample size and the wide range of definitions for respiratory depression in studies examined.
Journal of opioid management 6(1):47-54.
