Biomedical subjects

Richard M Langford

Publications and source records attributed to Richard M Langford.

5 recordsLinked to original sources

PubMed2006

Pain management today - what have we learned?

Pain is a leading cause of morbidity worldwide, with published data showing its prevalence as high as 50% for chronic pain in the European population. This prevalence is likely to continue to rise, particularly in elderly people with comorbid conditions and complex aetiologies of pain. There is thus a rapidly growing demand for safe and effective pain management. Management of mild-to-moderate pain has traditionally been based upon the use of non-steroidal anti-inflammatory drugs (NSAIDs) and the synthetic non-opioid analgesic paracetamol (acetaminophen), the latter of which acts centrally, inhibiting brain cyclo-oxygenase (COX) and nitric oxide synthase. Both the NSAIDs and paracetamol are effective for mild-to-moderate pain and are widely recommended and used. However, NSAIDs may not be tolerated due to gastrointestinal (GI) symptoms and can result in potentially fatal peptic ulceration and bleeding. Selective COX-2 inhibitors were developed to reduce the GI side effects and complications, but large-scale studies have highlighted another serious potential effect of anti-inflammatory drugs: cardiovascular events. Both the European Medicines Agency (EMEA) and the Food and Drugs Administration (FDA) in the US have issued advice to apply cautions and restrictions when prescribing COX-2 inhibitors, particularly for patients at increased cardiovascular risk and for long-term use. The FDA also applied cardiovascular warnings with regard to nonselective NSAIDs. Both the EMEA and the FDA have recommended using the lowest effective dose for the shortest duration. These concerns and warnings have left physicians seeking safe alternatives to anti-inflammatory drugs for both short- and long-term uses in many patients. These developments have generated a climate of uncertainty in the absence of official guidance on the selection of alternative analgesic regimens. Amongst the possible strategies, combinations of drugs that provide analgesic efficacy at reduced individual doses may confer the optimal risk-benefit ratio for pain management in the long term or in patients at increased cardiovascular risk. Weak opioids devoid of serious organ-damaging effects combined with paracetamol may well be safer for long-term therapy. Fixed-dose combinations of paracetamol with weak opioids, such as codeine, dextropropoxyphene or tramadol are currently available. Paracetamol plus tramadol is an effective and safe multimodal analgesic regimen for the management of both acute and chronic moderate-to-severe pain. Re-evaluating the role of weak opioids, such as tramadol, and combinations in pain management may prove a valuable option for prescribers seeking alternatives to anti-inflammatory drugs.

Analgesics↗

PubMed2006

Focused ion beams techniques for nanomaterials characterization.

Focused ion beam and dual platform systems have, over the last 10 years, become a main stay of sample preparation for material analysis. In this article the merits of using these systems are discussed and the three main techniques used to prepare cross-section specimens for transmission electron microscopy (TEM) are both discussed and compared with emphasis being placed on the tricks that users do to make the lamellae as thin as possible and with a minimum of damage at their sidewalls. Other techniques such as serial slicing for three-dimensional reconstruction and the preparation of plan-view specimens are also summarized.

Ions↗

PubMed2006

Safety and efficacy of the cyclooxygenase-2 inhibitors parecoxib and valdecoxib after noncardiac surgery.

BACKGROUND: Valdecoxib and its intravenous prodrug parecoxib are reported to increase thromboembolic risk after coronary artery bypass grafting. The authors conducted a randomized trial to examine their safety and analgesic efficacy in patients recovering from major noncardiac surgical procedures. METHODS: The trial was randomized and double-blind, with 10 days of treatment and 30 days of follow-up. Patients (n = 1,062) received either parenteral parecoxib for 3 days and oral valdecoxib for the rest of the treatment period or placebo medications throughout. The frequency of predefined adjudicated postrandomization adverse events, including cardiovascular thromboembolism, renal dysfunction, gastroduodenal ulceration, and wound-healing complications, was assessed in each group. Secondary efficacy endpoints included patients' pain ratings, opioid analgesic consumption (recorded as morphine equivalents), and reports of opioid-related adverse effects. RESULTS: Predefined adjudicated adverse events had similar frequencies among patients who received parecoxib and valdecoxib (2.7%) and placebo patients (3.2%) (P = 0.58), including cardiovascular thromboembolic events (1.0% in each group; P = 1.0). Placebo patients consumed more morphine equivalents (66.2 +/- 92.4 mg) than did patients receiving parecoxib and valdecoxib (43.2 +/- 65.7 mg) (P < 0.001). Placebo patients had higher mean pain ratings on each of study days 2-10 (P < 0.01) and reported more opioid-related symptom distress on days 2-6 (P < 0.01). CONCLUSIONS: Parecoxib and valdecoxib are useful adjuncts to opioids for the treatment of postoperative pain in noncardiac surgical patients. Further study will be required to determine the safety profile of parecoxib and valdecoxib administered to patients with known atherosclerotic disease after noncardiac surgery.

Adult↗

PubMed2005

Complications of the COX-2 inhibitors parecoxib and valdecoxib after cardiac surgery.

BACKGROUND: Valdecoxib and its intravenous prodrug parecoxib are used to treat postoperative pain but may involve risk after coronary-artery bypass grafting (CABG). We conducted a randomized trial to assess the safety of these drugs after CABG. METHODS: In this randomized, double-blind study involving 10 days of treatment and 30 days of follow-up, 1671 patients were randomly assigned to receive intravenous parecoxib for at least 3 days, followed by oral valdecoxib through day 10; intravenous placebo followed by oral valdecoxib; or placebo for 10 days. All patients had access to standard opioid medications. The primary end point was the frequency of predefined adverse events, including cardiovascular events, renal failure or dysfunction, gastroduodenal ulceration, and wound-healing complications. RESULTS: As compared with the group given placebo alone, both the group given parecoxib and valdecoxib and the group given placebo and valdecoxib had a higher proportion of patients with at least one confirmed adverse event (7.4 percent in each of these two groups vs. 4.0 percent in the placebo group; risk ratio for each comparison, 1.9; 95 percent confidence interval, 1.1 to 3.2; P=0.02 for each comparison with the placebo group). In particular, cardiovascular events (including myocardial infarction, cardiac arrest, stroke, and pulmonary embolism) were more frequent among the patients given parecoxib and valdecoxib than among those given placebo (2.0 percent vs. 0.5 percent; risk ratio, 3.7; 95 percent confidence interval, 1.0 to 13.5; P=0.03). CONCLUSIONS: The use of parecoxib and valdecoxib after CABG was associated with an increased incidence of cardiovascular events, arousing serious concern about the use of these drugs in such circumstances.

Administration, Oral↗

PubMed2002

Esophageal pulse oximetry utilizing reflectance photoplethysmography.

Peripheral perfusion is often poor and barely pulsatile in patients undergoing prolonged major surgery. Hence, the arterial blood oxygen saturation (SpO2) readings from commercial finger pulse oximeters can become unreliable or cease when they are most needed. To overcome this limitation, the esophagus has been investigated as an alternative measurement site, as perfusion may be preferentially preserved centrally. A reflectance esophageal pulse oximeter probe, and a processing system implemented in LabVIEW were developed. The system was evaluated in clinical measurements on 49 cardiothoracic surgery patients. The SpO2 values from the esophagus were in good agreement with arterial blood oxygen saturation (SaO2) values obtained from blood gas analysis and CO-oximetry. The means (+/-SD) of the differences between the esophageal SpO2 and SaO2 results from blood gas analysis and CO-oximetry were 0.02 +/- 0.88% and -0.73 +/- 0.72%, respectively. In five (10.2%) of the patients, the finger pulse oximeter failed for at least 10 min while the esophageal SpO2 readings remained reliable. The results confirm that the esophagus may be used as an alternative monitoring site for pulse oximetry even in patients with compromised peripheral perfusion.

Adult↗