Angiostomy Cannulae for the Study of Pulmonary Circulation. ∗ †

London(1) used angiostomy cannulae for the purpose of directing hypodermic needles into the larger thoracic vessels. Daly(2) reported the measurement of pulmonary arterial pressure in the unanesthetized dog by means of the London Type cannulae. Johnson, Hamilton. Katz and Weinstein(3) in the same year studied the dynamics of pulmonary circulation by means of hypodermic manometers, the needles being placed in the aorta, pulmonary artery and pulmonary vein. Hamilton, Woodbury and Vogt(4) studied differential pressures in the lesser circulation of the unanesthetized dogs using angiostomy cannulae and hypodermic manometers. Katz and Steinitz(5) developed a modification of the angiostomy cannulae used by Hamilton, and used their cannulae in measuring pulmonary arterial pressures.

The purpose of this paper is to report the development of a technic permitting direct access to the atria and large thoracic vessels of unanesthetized dogs under conditions which may be compared to normal.

Methods. Two varieties of cannulae were developed and used. The first variety, shown in Fig. 1, a., consists of silver tubes (3 mm outside diameter) fitted with perforated silver plates, one type of which is trough-shaped, to fit over the left pulmonary artery. A second type is flat and oval in shape, suitable for attachment to the left atrium. The length of each silver tube is such that its distal end, the heart serving as reference point, will lie immediately under the skin of the chest wall. The perforated silver plates are made from 2 mm silver stock. The plate attachment that is fitted over the left pulmonary artery is 8 mm long and of sufficient width so that when bent in a semicircle of the correct radius it extends over half the circumference of the vessel. The oval plate for attachment to the left auricle measures 15 mn1 by 10 mm. The cannula tube is fixed in an opening 5 mm from one end of the oval plate.