Efficacy of One Dose of Laxative on Postoperative Constipation Following Total Knee Arthroplasty.

Postoperative constipation is a common problem among orthopaedic surgical patients leading to discomfort, increased length of stay, and other complications. The primary purpose of this study was to determine the effectiveness of polyethylene glycol compared with docusate sodium for the prevention of constipation, after total knee arthroplasty. The secondary purpose was to examine the effectiveness of polyethylene glycol on pain and strain with bowel movement. A two-group nonequivalent cohort design was used to evaluate the effect of one 17-g dose of polyethylene glycol by mouth on postoperative day 1 compared with usual care with docusate sodium 100 mg starting the day of surgery and continued twice daily at home. There was no significant difference in the rate of constipation between the two cohorts in the 3 days after surgery. There was no difference in reported pain and strain. Future research should focus on the use of pharmacologic and nursing interventions together for prevention of postoperative constipation in patients with arthroplasty surgery.

Ethylmethanesulfonate saturation mutagenesis in Arabidopsis to determine frequency of herbicide resistance.

Plant resistance to glyphosate has been reported far less frequently than resistance to sulfonylurea and imidazolinone herbicides. However, these studies tend to be anecdotal, without side by side comparisons for a single species or natural isolate. In this study, we tested the frequencies of resistance of three herbicides in a controlled ethylmethanesulfonate (EMS) saturation mutagenesis experiment, allowing a direct comparison of the frequencies at which resistant mutant plants arise. The 100% growth inhibition dose rates of glyphosate, chlorsulfuron (a sulfonylurea herbicide), and imazethapyr (an imidazolinone herbicide) were determined for Arabidopsis. Populations of EMS-mutagenized M(2) seedlings were sprayed with twice the 100% growth inhibition dose of glyphosate, chlorsulfuron, or imazethapyr, and herbicide-resistant mutants were identified. Although there were no glyphosate-resistant mutants among M(2) progeny of 125,000 Columbia and 125,000 Landsberg erecta M(1) lines, chlorsulfuron resistance and imazethapyr resistance each appeared at frequencies of 3.2 x 10(-5). Given the observed frequency of herbicide resistance mutations, we calculate that there are at least 700 mutations in each EMS-mutagenized Arabidopsis line and that fewer than 50,000 M(1) lines are needed to have a 95% chance of finding a mutation in any given G:C base pair in the genome. As part of this study, two previously unreported Arabidopsis mutations conferring resistance to imidazolinone herbicides, csr1-5 (Ala-122-Thr) and csr1-6 (Ala-205-Val), were discovered. Neither of these mutations caused enhanced resistance to chlorsulfuron in Arabidopsis.

Peripheral nerve blocks for postoperative analgesia.

Peripheral nerve blocks are used as part of a preemptive and multimodal analgesic technique to provide safe and effective postoperative pain management with minimal side effects. They are used for a variety of surgical procedures in both inpatient and outpatient settings. Peripheral nerve blocks have resulted in shorter recovery times, decreased anesthesia-related complications, and better postoperative pain management. Peripheral nerve blocks, as part of a multimodal analgesic regimen, have decreased recovery times by lessening side effects (e.g., nausea, vomiting, drowsiness). Nerve blocks have allowed procedures previously performed only in hospitals to be performed on an outpatient basis by providing extended surgical area analgesia. The use of peripheral nerve blocks, however, requires skilled and knowledgeable clinicians. This article discusses the mechanism of action and the role of peripheral nerve blocks in multimodal analgesia, as well as perioperative nursing implications and management for upper and lower extremity peripheral nerve blocks.