RESUMEN
High-flow nasal oxygen is increasingly used in complex head and neck surgical procedures and difficult airway management. We describe a case where an operating room fire occurred while using high-flow nasal oxygen during an awake tracheostomy for an obese patient in airway extremis due to supraglottitis. Shortly after the operation began, and before incision of the trachea, electrical diathermy applied to bleeding sub-cutaneous vessels ignited a small flame. This was extinguished without harm to the patient and the procedure was completed without further complication. Fire requires three components: fuel; heat; and an oxidiser. We speculate that high-flow oxygen channelled under the drapes and acted as the oxidiser; either tissue eschar or vapourised fat were the fuel; and the diathermy supplied a source of ignition to complete the fire triad. When using high flows of concentrated oxygen, practitioners should aim to minimise all of these factors and be alert for the risk of fire at every stage of the operation.
RESUMEN
Background Far-infrared-emitting garments have several biological properties including the capability to increase blood perfusion in irradiated tissues. Design The aim of the study was to evaluate whether far-infrared radiation increases exercise capacity and delays anaerobic metabolism in healthy subjects. Methods With a double-blind, crossover protocol, a maximal cardiopulmonary exercise test was performed in 20 volunteers, wearing far-infrared or common sport clothes, identical in texture and colour. Results Comparing far-infrared with placebo garments, higher oxygen uptake at peak of exercise and longer endurance time were observed (peak oxygen uptake 38.0 ± 8.9 vs. 36.2 ± 8.5 ml/kg/min, endurance time 592 ± 85 vs. 570 ± 71 seconds; P < 0.01); the anaerobic threshold was significantly delayed (anaerobic threshold time 461 ± 93 vs. 417 ± 103 seconds) and anaerobic threshold oxygen uptake and anaerobic threshold oxygen pulse were significantly higher (25.3 ± 6.4 vs. 20.9 ± 5.4 ml/kg/min and 13.3 ± 3.8 vs. 12.4 ± 3.3 ml/beat, respectively). In 10 subjects the blood lactate concentration was measured every 2 minutes during exercise and at peak; lower values were observed with far-infrared fabrics compared to placebo from the eighth minute of exercise, reaching a significant difference at 10 minutes (3.6 ± 0.83 vs. 4.4 ± 0.96 mmol/l; P = 0.02). Conclusions In healthy subjects, exercising with a far-infrared outfit is associated with an improvement in exercise performance and a delay in anaerobic metabolism. In consideration of the acknowledged non-thermic properties of functionalised clothes, these effects could be mediated by an increase in oxygen peripheral delivery secondary to muscular vasodilation. These data suggest the need for testing far-infrared-emitting garments in patients with exercise limitation or in chronic cardiovascular and respiratory patients engaged in rehabilitation programmes.