A closed loop microprocessor controller for treatment of hypertension after cardiac surgery

Hypertension after cardiac surgery is common and requires accurate control by carefully regulated infusions of drugs such as sodium nitroprusside. A microprocessor-based controller has been designed to close the loop between the blood pressure response and the infusion rate of a hypotensive drug. This system has been refined by computer simulation of the blood pressure response to sodium nitroprusside and by experience gained in using the controller in eleven patients in the early recovery period after cardiac surgery. The controller was able automatically to maintain blood pressure within 10% of a specified value. Provision of sophisticated safety features in automatic drug infusion controllers is essential for patient protection.     

Reepithelialization of experimental scalds effected by topically applied superoxide dismutase: controlled animal studies

Highly reactive metabolites, such as oxygen free radicals, initiate a cascade of inflammatory processes in thermally damaged skin, leading to enhanced tissue loss and delayed wound healing. The extent of tissue necrosis in the zone of stasis is of prognostic significance in the wound healing process. In this study, the effect of oxygen free radical removal by recombinant human-Cu/Zn-superoxide dismutase, given in three different formulations during the inflammatory postburn phase and wound repair, was examined. Recombinant human superoxide dismutase was either injected directly into the lesions, spread as enzyme-containing gel onto the burned tissue, or encapsulated into liposomes consisting of 1,2 dipalmitoy-sn-glycero-3-phosphocholine, cholesterol and stearylamine, suspended into a hydrophilic gel and administered to burned animals immediately after trauma. Controls were treated with plain gel or kept untreated. Edema formation, size of lesions, deepening of necrosis, and reepithelialization were examined. Results indicate that superoxide dismutase treatment resulted in reduced and faster recruitment of edema formation, smaller wound sizes, and minor tissue necrosis compared to the controls, thus resulting in significantly faster reepithelialization after 3 weeks. These animal studies on the efficacy of liposomal oxygen free radical scavenger showed accelerated wound healing in all parameters tested.     

Microsurgical medialis pedis flaps for reconstruction of soft-tissue defects in the hand.

The medialis pedis flap (MPF) has been used for the reconstruction of soft-tissue defects in the hand since 1990. From January 1997 through January 2000, 19 patients (15 male, 4 female) with hand injuries underwent microsurgical MDF reconstruction at Chang Gung Memorial Hospital. There were finger injuries in 16 patients and palm defects in 3 patients. The mean patient age was 32.6 years (age range, 16-58 years). Flap size ranged from 4.5 x 2 cm to 7 x 6 cm (mean, 6 x 2.8 cm). Only one flap had partial loss. The donor site was closed primarily in 9 patients, and was closed using a split-thickness skin graft in 9 patients and a full-thickness skin graft in 1 patient. At a mean follow-up of 13 months, the protective sensation was 16 mm using the static two-point discrimination test and was 10 mm using the moving two-point discrimination test. Based on this retrospective study the authors conclude that (1) the MPF has the advantages of thin and glabrous skin, (2) the size of pedicle is compatible with the recipient vessel in the hand, (3) there is low donor site morbidity, and (4) achieving protective sensation is possible.     

The Environmental Context of Patient Safety and Medical Errors

The environmental context of patient safety and medical errors was explored with specific interest in rural settings. Special attention was paid to unique features of rural: healthcare organizations and their environment that relate to the patient safety issue and medical errors (including the distribution of patients, types of adverse events associated with learning, information flows, triage and transfer decisions, and culture of safety). Relevant organizational theories and strategies fo medical error reduction and prevention in rural health care settings were identified. Financial and technical assistance are needed to support the systematic collection of data from rural hospitals and other entities and to enhance relevant patient safety practices for rural America.     

Resorption rate and biocompatibility characteristics of two polyester ventilation tubes in a guinea pig model

OBJECTIVES: Determine the resorption rate and biocompatibility characteristics of 2 polyester ventilation tubes, and to determine whether soap and water exposure accelerates polyester tube degradation. STUDY DESIGN AND SETTING: 50/50 poly (D, L-lactide-co-glycolide; PLGA-50) and poly (L-lactide; PLA) polymers were placed into the tympanic membranes of Hartley pigmented guinea pigs. Integrity of the tubes was determined by weekly otoscopic examination. Biocompatibility was assessed by comparing auditory brainstem response (ABR) thresholds and by examining tympanic membrane changes following tube resorption. Shah minigrommet ventilation tubes were used as controls. In the second portion of this study, implanted PLGA-50 and PLA tubes were exposed weekly to a mixture of soap and water (1:5) until complete resorption was observed. Biocompatibility was assessed by periodic ABR testing and tympanic membrane examination. RESULTS: The PLA tubes remained in the tympanic membrane for a longer period (63.2 +/- 19.3 days) than the PLGA-50 (18.8 +/- 8.1 days). The tympanic membrane and resorbable tube interface demonstrated equivalent findings for auditory thresholds and tissue histopathology at the implant site compared to nonresorbable controls. The resorption behavior was not altered by exposure to soap and water. Tympanic membranes of all animals following tube degradation and soap water exposure were intact with minimal scarring and no signs of persistent foreign body response. The histological analysis showed that implantation of resorbable tubes was not accompanied by secondary infection with otorrhea through the tube, did not result in a permanent perforation or dislocation of the tube into the middle ear cavity, and was not followed by excess tympanosclerosis or localized or diffuse membrane atrophy. CONCLUSIONS AND SIGNIFICANCE: Resorbable polyester pressure equalization tubes demonstrate predictable resorption behavior and similar biocompatibility characteristics when compared with nonresorbable Shah minigrommet ventilation tubes. Exposure to soap water does not accelerate polyester tube degradation nor change the host tissue response during the indwelling period or after complete resorption. The data suggests that resorbable ventilation tubes are substantially equivalent to other FDA-approved tympanostomy devices with regard to safety and biocompatibility in the guinea pig model examined and may provide improved clinical performance by combining this approach with sustained release technology. EBM RATING: B-2.     

湿润烧伤膏治疗外伤性末节指(趾)骨外露体会

目的：探讨MEBO治疗骨外露的临床疗效。方法：对2005年10月至2006年2月处置外伤性指（趾）骨外露3例采用MEBO治疗。结果：3例创面全部愈合,时间均为3周。结论：MEBO治疗外伤性末节指（趾）骨外露简便,实用,疗效可靠,不影响美观。