Humidification and airway pressures during high-frequency jet ventilation delivered through the suction-biopsy channel of a flexible bronchofiberscope

The suction-biopsy channel (SBC) of a flexible bronchofiberscope was used to deliver gas into the trachea during high-frequency jet ventilation (HFJV) at a rate of 95 cycle/min and a tidal volume (VT) of 95 ml. A Portex epidural catheter inserted into the SBC was used to entrain water for humidification by the injector principle. Inspired humidity (IH) was regulated by adjusting the distance (D) between the injector and jet portals. Airway pressures, pulmonary gas exchange and IH levels were measured in 11 dogs. In addition, tracheal cytology scores (TCS, a sensitive index of tracheal epithelial damage caused by breathing dry gases) were assessed in 12 patients. The system maintained adequate pulmonary gas exchange in both dogs and humans. In dogs the mean tracheal pressure was 2.8 +/- 0.5 (SD) torr with a peak pressure of 3.8 +/- 0.5 torr. The upper-airway pressure was subatmospheric (-2 +/- 0.2 torr) during the first half of jet inspiration, but peaked synchronously with tracheal pressures during the second half. Both the upper airway and the trachea had a positive end-expiratory pressure (PEEP) of 1.8 +/- 0.2 torr. When D was 0.3 cm, the system delivered gas with an IH of 44 mg H2O/L (almost saturated at 37 degrees C). Human TCS did not change significantly after 2 h of humidified HFJV, suggesting efficient humidification.     

Relation of thyroid hormone secretion rate (TSR) in rats and fowl to hormone content of their thyroid glands

By the determination of thyroid hormone secretion rate (TSR), the amount of l-thyroxine (l-T₄) secreted each 24 hr has been estimated. An attempt has been made in this study to determine by bioassay the relation of the daily TSR to the amount of stored hormone (thyroglobulin) in the thyroid of the rat and chicken in terms of l-T₄ equivalents. The individual TSR of 28 rats and 36 chickens was determined. Two animals having the same TSR were grouped as the donor and recipient of the thyroid homogenate. To bioassay the l-T₄ equivalents of donor thyroids, recipient rats and chickens were injected with graded levels of the thyroid homogenate until release of thyroidal ¹³¹I was blocked according to the technique used in the estimation of TSR. Mean l-T₄ equivalents in the thyroids of donor rats and chickens were 13.9 and 154.4 μg with a daily secretion of 3.58 and 27.98 μg, respectively. The amount of l-T₄ equivalent in the thyroid homogenate was 3.82 ± 0.35 times the daily TSR in rats and 5.56 ± 0.23 times in chickens (P < 0.001). The data suggest that in rats and chickens there is a significant difference in the magnitude of bioassayable l-T₄ equivalents stored in the thyroid in terms of daily TSR.     

Obturator hernia

Four cases of strangulated obturator hernia are presented with a brief review of the literature up to 1980. All four patients were emaciated women over 50 years old and in all instances the hernia was on the left side. None of the cases was diagnosed preoperatively and all had Howship-Romberg's sign absent. A diagnosis of strangulated obturator hernia should always be considered in any elderly, thin female with clinical features of intestinal obstruction and without any history of previous abdominal operations. Three of the patients died due to delayed presentation, delayed operative interference and rupture of the gangrenous loop leading to septicaemia.