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Lymphatic flow rates and first‐aid in simulated peripheral snake or spider envenomation
Author(s) -
Howarth Douglas M,
Southee Andrew E,
Whyte Ian M
Publication year - 1994
Publication title -
medical journal of australia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 131
eISSN - 1326-5377
pISSN - 0025-729X
DOI - 10.5694/j.1326-5377.1994.tb126923.x
Subject(s) - bandage , medicine , lymphatic system , surgery , upper limb , anesthesia , pathology
Objectives To demonstrate and define normal lymphatic transit times by lymphoscintigraphy and to evaluate the efficacy of the currently recommended first‐aid measures for the management of snake or spider envenomation. Setting The nuclear medicine department of a major teaching hospital. Participants and design Twenty‐four subjects received either intra‐dermal or subcutaneous injections of “technetium antimony sulfur colloid (0.1 mL) in both hands/forearms and feet/legs. This simulated a snake or spider bite. Fifteen of the subjects had first‐aid in the form of firm bandages and splints applied to an upper and a lower limb immediately after injection. Main outcome measures The progress of the radiotracer was followed with a large field of view gamma camera. If no egress of radiotracer was seen in the bandaged limbs, the subject walked until radioactivity was detected. Results The mean (± SEM) periphery‐to‐systemic circulation transit time after subcutaneous injection was 58 (± 7) minutes. The first‐aid was found to be very effective when applied with bandage pressures ranging from 40 to 70mmHg (5.3‐9.3kPa) in the upper limb and 55 to 70 mmHg (7.3‐9.3 kPa) in the lower limb. Lower and higher bandage pressures were ineffective. However, despite first‐aid measures, egress of radiotracer, even in the upper limbs, was seen in all subjects who walked for 10 minutes or more. Conclusions Firm pressure bandaging is an effective means of restricting the lymphatic flow of toxins after envenomation, provided the bandage is applied within the defined pressure range. Strict limb immobilisation is necessary to minimise lymphatic flow, and walking after upper or lower limb envenomation will inevitably result in systemic envenomation despite first‐aid measures.