Distribution assessment comparing continuous and periodic wound instillation in conjunction with negative pressure wound therapy using an agar-based model.

Negative pressure wound therapy (NPWT) is a widely accepted and effective treatment for various wound types, including complex wounds. Negative pressure with instillation was initially used as a gravity-fed system whereby reticulated, open-cell foam in the wound bed was periodically exposed to cycles of soaking with instillation solution followed by NPWT. Recent publications have alluded to positive outcomes with continuous instillation, where fluid is delivered simultaneously with negative pressure. To evaluate the distribution of instillation solutions to wound beds in conjunction with negative pressure, agar-based models were developed and exposed to coloured instillation solutions to identify exposure intensity via agar staining. This model allowed comparison of continuous- versus periodic-instillation therapy with negative pressure. Continuous instillation at a rate of 30 cc/hour with negative pressure showed isolated exposure of instillation fluid to wound beds in agar wound models with and without undermining and tunnelling. In contrast, periodic instillation illustrated uniform exposure of the additive to the entire wound bed including undermined and tunnel areas, with increased staining with each instillation cycle. These findings suggest that periodic instillation facilitates more uniform exposure throughout the wound, including tunnels and undermining, to instillation solutions, thereby providing therapy consistent with the clinician-ordered treatment.

Negative Pressure Wound Therapy With Controlled Saline Instillation (NPWTi): Dressing Properties and Granulation Response In Vivo.

Negative pressure wound therapy (NPWT) with reticulated open-cell foam (ROCF) dressings (ROCF G, V.A.C.® GranuFoamTM Dress- ing, KCI USA, Inc, San Antonio, TX) creates a healing environment that removes wound exudates, reduces edema, and promotes perfusion and granulation tissue formation. Controlled instillation of saline dur- ing NPWT (NPWTi) may further enhance healing by facilitating auto- matic and contained volumetric wound irrigation and cleansing. A new ROCF dressing (ROCF-V, V.A.C. VeraFloTM Dressing, KCI USA, Inc, San Antonio, TX) has been developed for use with NPWTi; benchtop and in vivo tests compared the properties and performance of both ROCF-G and ROCF-V. Pore size and density (contributors to microdeformation) are similar for both ROCF-G and ROCF-V, while mechanical testing demonstrates ROCF-V is stronger than ROCF-G under both tensile and tear loading. ROCF-V surface energy is higher than ROCF-G, making ROCF-V less hydrophobic. Under wet conditions ROCF-V wicks more fluid and shows less pressure drop than ROCF-G, suggesting ROCF-V may be better suited for NPWTi. After 7 days of therapy in a porcine full-thickness excisional wound model, NPWTi with ROCF-V resulted in a 43% increase (P < 0.05) in granulation tissue thickness compared to NPWT with ROCF-G. These data suggest NPWTi with ROCF-V creates a wound healing environment that provides enhanced granulation tissue formation compared to standard NPWT with ROCF-G. .

The effect of supporting a surgeon's wrist on their hand tremor.

BACKGROUND: Operative tremor can greatly influence the outcome of certain, precise, microsurgical operations. Reducing a surgeons tremor may not only improve the operative results but decrease the operative time. Previous studies have only measured uni or bi directional tremor and therefore have been unable to calculate both the overall tremor amplitude and the tremor reduction by resting the wrists. MATERIALS AND METHODS: We measured the tremor of 21 neurologically normal volunteers while performing a micromanipulation task, with and without wrist support. Measurements were acquired in three dimensions using three accelerometers attached to the hand, allowing an overall tremor amplitude to be calculated. RESULTS: Resting the wrist on a gelled surface decreases an individuals tremor by a factor of 2.67 (P = 0). CONCLUSIONS: Supporting the wrists significantly decreases the amplitude of the tremor. Surgeons should consider using wrist supports when performing parts of operations which necessitate a high degree of accuracy.

The effect of operating time on surgeon's hand tremor.

The objective of this prospective study, performed at two tertiary referral centers in the West Midlands, was to determine if operating has an effect on a surgeon's baseline tremor. A total of 10 head and neck surgery consultants, 2 ENT registrars and 19 normal controls participated in the study. The interventions were preoperative and postoperative tremor measurements for surgeons and pre and post-days' desk work for controls, with the main outcomes measure being the percentage change in tremor. No difference in baseline tremor was determined between consultants and registrars. Operating led to an increase in hand tremor in all subjects. Tremor increases in all subjects were directly proportional to the length of the time spent in operating. Operating compared to a normal day's desk work increased tremor by a factor of 8.4. In conclusion, surgeons should be aware that their tremor will increase as an operation progresses. More complex parts should be performed as early in the day as possible, or, in the case of a very long operation, a change of surgeons may occasionally be necessary.