Thorax: first published as 10.1136/thx.16.4.325 on 1 December 1961. Downloaded from Thorax (1961), 16, 325. THE TECHNIQUE OF HYPOTHERMIC PERFUSION BY P. J. MOLLOY* AND R. I. LINDFIELD From the Thoracic Surgical Unit, Guy's Hospital, London (RECEIVED FOR PUBLICATION OCTOBER, 1961) This report is to describe the machine for extra- drilled with two holes, one I in. in diameter connected corporeal circulation in use at Guy's Hospital, to to the coronary suction reservoir and one I in. in discuss the technique of preparing and assembling diameter connected to the venous return lead from the circuit, and to indicate the method of hypo- the patient. The connexions are stainless steel and are sealed by 0 rings which are compressed by flanges thermic perfusion. engaging in lugs on the under surface of the cover plate. All blood from the patient is returned to the THE MACHINE AND EXTRACORPOREAL CIRCUIT circuit and blood loss is kept to a minimum. The The machine described is in commercial production upper cover plate has a 3/16 in. hole for placing the although the perfusions, to date, were performed with thermometer to monitor mixed venous blood tempera- the prototype described by Ross (1960a). The extra- ture, a I in. hole to receive the left atrial vent, and copyright. corporeal circuit is mounted on the front of the a 5/16 in. hole to prevent pressure build-up in the machine (Fig. 1) under the vision of the perfusionist venous reservoir. and comprises: Blood is returned to this reservoir by gravity Coronary suction reservoir (A) into which all drainage, the patient being 14 in. above the machine blood level. This reservoir acts as a debubbling wound and coronary sinus blood is returned by chamber and its level is maintained above the top suction from a horizontally mounted de Bakey pump http://thorax.bmj.com/ (B). This reservoir contains a filter of six coarse of the entry port into the oxygenating chamber to steel meshes and one fine mesh separated by which it is clamped, a blood-tight seal being effected stainless an 0 a recess on the I in. nylon spacers, mounted on a central rod over ring seated in oxygenator suspended from the cap of the reservoir. This filter end plate. is to defoam blood and trap any particles of tissue, The oxygenator chamber (G) is a cylinder of clear fat, or calcium which may return to the circuit. The Perspex 12 cm. in diameter and 50.7 cm. long, closed meshes are coated with silicone antifoam (MS " A "), by two removable end plates bolted together outside the only place in the circuit where this substance is the cylinder. The end plates are drilled centrally to used. On the cover of the reservoir is an entry port support a nylon bearing which is itself drilled 2 mm. for the recirculating lead (C) which is used for mixing eccentrically to support the spindle on which the discs on September 24, 2021 by guest. Protected drugs and maintaining blood temperature during are mounted. This allows more of the disc surface to periods of circulatory arrest. There are four 3/16 in. enter the blood without increasing the priming holes drilled in this disc to receive the giving set volume. The venous end plate is drilled at its lower nozzles used for priming the circuit. The bottom edge to receive the venous reservoir as described disc is pierced by a I in. hole to receive a lead of above. Blood flows into the chamber, is picked up X in. " tygon " (D) connecting to the venous reservoir as a film on the discs, and oxygenated. The discs (E). This lead is interrupted by a Y piece connected rotate at 120 or 40 revolutions per minute, the slower to an ancillary circuit (F) to bleed the machine should speed being employed during preparation and periods return become embarrassingly profuse. of circulatory arrest to minimize blood traumna. Pro- vision is made for a bracket on which a scond The venous reservoir (E) is a cylinder of clear oxygenator can be mounted in parallel to pr'ide Perspex 7 cm. in internal diameter with removable sufficient oxygenating surface for full normotmic top and bottom cover plates which are approximated flows. by rubber 0 rings, rigid rods, and bolts. This makes for ease in cleaning and removes crevices where stale The arterial end plate has two 3/16 in. holes drilled blood may remain and give rise to pyrogenic reactions to receive the oxygen leads, two hollow rods which in subsequent patients. The lower cover plate is traverse the full length of the chamber and have multiple perforations. Oxygen is supplied by a lead *Leverhulme research fellow. from the cylinders (H) after bubbling through saline. Thorax: first published as 10.1136/thx.16.4.325 on 1 December 1961. Downloaded from 326 P. J. MOLLOY and R. 1. LINDFIELD axb Eve E r} .... [# 4 : = t;1nt .S.. ... |S _ _ copyright. _ _I .^_ http://thorax.bmj.com/ 1. 1,. t.si:' ., ft9- * H .k, on September 24, 2021 by guest. Protected 4 .sb.f S u1 oX mF1 K s AL _/'} \e s! tj; > L2 - ! L ON Thorax: first published as 10.1136/thx.16.4.325 on 1 December 1961. Downloaded from THE TECHNIQUE OF HYPOTHERMIC PERFUSION 327 II copyright. -M FIG. I (3) http://thorax.bmj.com/ FIG. 1.-This figure shows the machine from different aspects. (1) From perfusionist's side. (2) From arterial pump end. (3) 'From reservoir end. A, Coronary suction reservoir; B, suction pump of de Bakey type; C, recirculating lead; D, connecting tube; E, venous reservoir; F, ancillary bleeding-off lead; G, oxygenator chamber; H, oxygen supply; J, arterial pump of de Bakey type; K, heat exchanger; L1-L2, inlet and outlet leads for heat exchanger fluid; M, filter chamber. The discs are flat, stainless steel plates 10.8 cm. in heads have been abandoned as it is thought a high diameter and 1 mm. thick. They are separated from pressure channel may be forced into the V between each other by 4 mm. nylon spacers. There are 100 the heads and give rise to haemolysis. The heads discs in an adult lung and 60 in the smaller cylinder sweep more than half the diameter of the pump used for children. When 2.4 cm. of disc perimeter is casing, thus ensuring constant occlusiveness. dipping in the blood 126.7 sq. cm. of surface is From the pump blood enters the heat exchanger on September 24, 2021 by guest. Protected exposed to the chamber atmosphere per revolution, (K) at the bottom through a I in. steel tube. Inside i.e., at 120 r.p.m. 152 sq. metres is exposed per the cap is a space above which the blood enters 19 minute. Although the discs are precision made, care 5 mm. tubes which traverse the lumen of a water is taken to ensure they are wettable; no silicone or jacket which itself is completely discrete from the antifoam is used nor is a high polish felt desirable. blood (Fig. 2). Tubes (Li and L2) connect the jacket The centre spindle is connected by a pulley and belt to the cooling and heating units mounted under the drive to a small motor mounted under cover at the chassis. The exchange inflow and output are at 180° arterial end of the chassis. to each other to improve exchanger efficiency by Blood leaves the oxygenator by a I in. hole drilled reducing streaming effects. Blood re-collects into a in the cylinder at its most dependent point. A stainless single stream above the tubes and enters the filter steel connector sealed by an 0 ring and held by chamber (M). This consists of a central obturator flanges secured under lugs is joined to a 25 in. length drilled from below with a Y passage, surrounding of " esco " tubing of I in. internal diameter which which is a stainless steel fine mesh filter plate. This passes through the arterial pump (J) to the heat is contained by a stainless steel jacket with coarse exchanger (K). The pump is a de Bakey roller type perforations. The whole filter assembly is enclosed with a double arm. The heads are set to be occlusive in an outer casing perforated laterally by two holes. by a central, variable wedge adjuster which is then The upper screw cap, perforated by a 3 in. steel tube, fixed by two bolts seating on to slots in the roller completes the assembly. This upper take-off connects arms. The heads are single, 2.7 cm. in width. Twin to the recirculating lead (C). The lateral holes, 3 in. Thorax: first published as 10.1136/thx.16.4.325 on 1 December 1961. Downloaded from 328 P. J. MOLLOY and R. l. LINDFIELD in diameter, provide exit ports for the arterial and coronary artery perfusion leads. The arterial lead is j in. " tygon " and connects to a stainless steel cannula in the patient's external iliac artery. The coronary -1e1 D Li t t artery perfusion lead is connected via a I in.-t in. breakdown to a i in. length of "portex " tubing to which is attached a fine cannula. The volume of : c ki rI flow through this lead is controlled by a gate clip. ii Ri The control panels on the other side of the machine Heir3 Xct wig8" are as shown (Fig. 3). The arterial pump unit and I I suction pump units are interchangeable and have a Ii l :I ...