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Biomedical subjects

David Parsons

Publications and source records attributed to David Parsons.

6 recordsLinked to original sources
PubMed2006

Comparison of direct and video-assisted views of the larynx during routine intubation.

OBJECTIVE: To compare the direct and indirect (video monitor) views of the glottic opening using a new Macintosh blade that is modified to provide a video image of airway structures during laryngoscopy. DESIGN: Prospective multicenter trial. SETTING: 11 university-affiliated hospitals. PATIENTS: 867 adults undergoing elective surgery requiring general anesthesia and tracheal intubation. INTERVENTIONS: Patients received general anesthesia and were paralyzed. Direct laryngoscopy was supervised by one of the investigators at each institution. The best possible view was obtained with a Macintosh video laryngoscope during direct vision using standard techniques such as external laryngeal manipulation and backward, upward, and rightward pressure, if necessary. The laryngoscopist then looked at the video monitor and performed any necessary maneuvers to obtain the best view on the video monitor. Thus, 2 assessments were made during the same laryngoscopy (direct naked-eye view vs video monitor view). Tracheal intubation was then performed using the monitor view. Glottic views were rated according to the Cormack-Lehane scoring system, as modified by Yentis and Lee. A questionnaire was completed for each patient. MEASUREMENTS AND MAIN RESULTS: Data from 865 patients were suitable for analysis. Visualization was considered easy (Cormack-Lehane score<3) in 737 patients and difficult (Cormack-Lehane score=3 or 4) in 21 for both direct and video-assisted views. In 7 patients, the view was considered easy during direct visualization yet difficult on the video monitor view. On the other hand, the view was considered difficult in 100 patients during direct visualization yet easy on the video monitor view (P<0.001). CONCLUSIONS: Video-assisted laryngoscopy provides an improved view of the larynx, as compared with direct visualization. This technique may be useful for cases of difficult intubation and reintubation as well as for teaching laryngoscopy and intubation.

Adult↗
PubMed2006

Silver deposition and tissue staining associated with wound dressings containing silver.

Argyria is the general term used to denote a clinical condition in which excessive administration and deposition of silver causes a permanent irreversible gray-blue discoloration of the skin or mucous membranes. The amount of discoloration usually depends on the route of silver delivery (ie, oral or topical administration) along with the body's ability to absorb and excrete the administered silver compound. Argyria is accepted as a rare dermatosis but once silver particles are deposited, they remain immobile and may accumulate during the aging process. Topical application of silver salts (eg, silver nitrate solution) may lead to transient skin staining. To investigate their potential to cause skin staining, two silver-containing dressings (Hydrofiber and nanocrystalline) were applied to human skin samples taken from electively amputated lower limbs. The potential for skin discoloration was assayed using atomic absorption spectroscopy. When the dressings were hydrated with water, a significantly higher amount of silver was released from the nanocrystalline dressing compared to the Hydrofiber dressing (P <0.005), which resulted in approximately 30 times more silver deposition. In contrast, when saline was used as the hydration medium, the release rates were low for both dressings and not significantly different (silver deposition was minimal). Controlling the amount of silver released from silver-containing dressings should help reduce excessive deposition of silver into wound tissue and minimize skin staining.

Administration, Cutaneous↗
PubMed2002

The effect of huffing and directed coughing on energy expenditure in young asymptomatic subjects.

Coughing and huffing have been shown to be effective airway clearance techniques and some authors have anecdotally reported that a huff requires less energy than a series of coughs commencing and finishing at the same lung volume. The aim of this study was to determine whether there is a difference in the energy expenditure between periods of huffing and directed voluntary coughing commencing from the same initial lung volume in young asymptomatic subjects. Energy expenditure was measured using open-circuit indirect calorimetry equipment. Twenty-four non-smoking asymptomatic subjects (12 male, 12 female, aged 18-24 years), without any form of disease and within 10% of their predicted pulmonary function, completed the study. Energy expenditure was measured over three 10min, randomly ordered sessions of huffing, directed coughing and rest. The forced expiratory sessions comprised a single huff or double-barrel cough (both starting at total lung capacity) at the end of every two minutes. Each session was separated by a 5min washout period. No significant difference in energy expenditure was found between the huffing and directed coughing periods (mean difference 0.003 mL/kg/min (95% CI -0.160 to 0.114) and both produced significantly greater energy expenditure than rest (rest and huff mean difference 0.309 mL/kg/min (95% CI 0.080 to 0.549) and rest and cough mean difference 0.306 mL/kg/min (95% CI 0.074 to 0.508)). The suggested benefits of huffing versus coughing in terms of energy conservation are yet to be shown.

Adolescent↗
PubMedDate not supplied

Controlling wound bioburden with a novel silver-containing Hydrofiber dressing.

Clinicians now recognize that both aerobic and anaerobic microorganisms have the ability to degrade or damage host tissue at a wound site through the production of a variety of enzymes and toxins. Silver-containing dressings offer one method for controlling this polymicrobial wound bioburden, and research efforts are currently ongoing to determine their efficacy against aerobic, anaerobic, and antibiotic-resistant microorganisms. The current study aimed to determine the antimicrobial activity of a new silver-containing Hydrofiber dressing (AQUACEL Ag) on both aerobic and anaerobic microorganisms, using the zone-of-inhibition method. This method provides a measure of the ability of the dressing to make available a sufficient concentration of silver to have an antimicrobial effect. To some extent this test mimics the clinical use of the dressing and predicts its microbicidal activity at the wound-dressing interface. The results show that the silver-containing dressing makes silver available at a dressing-agar interface at a concentration that is effective against a broad range of aerobic, anaerobic, and antibiotic-resistant microorganisms. In the context of wound healing, the results showing antimicrobial activity against antibiotic-resistant microorganisms are particularly important, as the control and eradication of these organisms is a major concern within the health care profession.

Administration, Topical↗