1260 
MONITORING 
food is discontinued. Water fast begins at 12 to 
24 hours. 
Anesthesia and Surgery 
We have recently chosen intravenous 
ketamine^ (Ketalar) ** for the induction (12-16 
mg/kg) and maintenance (6-8 mg/kg given 
slowly every 15-20 minutes) of anesthesia. 
Succinyl choline (100 mgm) is given together 
with the initial ketamine dose to facilitate 
endotracheal intubation since the latter drug 
preserves pharyngeal reflexes. Using ketamine, 
induction was seen within 30-40 seconds and 
the long post-operative sedation period inherent 
with the use of barbituates (12 hours or more) , 
fluothane or fluothane and nitrous oxide mix- 
tures (3-4 hours) was avoided. Ketamine has 
also negated the need for additional and ex- 
pensive anesthesia equipment, such as absorber 
circuits and a recirculation apparatus which are 
necessary with volatile anesthetics. In addition, 
an anesthetist is not required. To date, hypo- 
tension or respiratory depression has not been 
observed with this agent. 
Endotrachael intubation was accomplished 
with a Size 44F endotrachael tube and a long 
bladed laryngoscope. Adequate cuff inflation 
was checked by manual compression of the 
lower thoracic cage and diaphragm. Ventilation 
was maintained via a pressure cycled respirator 
(Bird Mark VII or VIII) at an average inspira- 
tory pressure of 20-22 cm of water (range 
18-30). Compressed air or various oxygen-air 
mixtures was adequate for these purposes. Peri- 
odic sighing was utilized during thoractomy 
and closure to minimize atelectasis. Blood PO2, 
pCOo and pH were checked throughout the op- 
erative procedure to aid in their maintenance in 
the physiological range.^ 
Succinylcholine (Anectine) * blockade was 
used during the incision of the thoracic muscu- 
lature. An intravenous bolus injection (40 mg) 
or drip (600 mg/500 cc saline) has been found 
adequate for these purposes. 
Pre-operative hematocrit and central venous 
pressure via the jugular vein were obtained as a 
guide to subsequent fluid replacement. A liter of 
* Burroughs Wellcome. 
** Parke-Davis, Detroit, Michigan. 
normal saline or Ringer's lactate containing 5 
million units of penicillin was routinely given 
during each case. Blood replacement was rarely 
necessary; however, when needed, unmatched 
donor blood from adult cattle has been used 
without reaction. 
In the right recumbent position with the neck 
and left chest shaved and prepped using stand- 
ard procedures, the jugular vein was isolated 
and cannulated and the chest entered through 
the fifth intercostal space. When more extensive 
exposure was necessary, the fifth rib was re- 
sected. The toleration to resection has been 
quite satisfactory. Once in the chest, the peri- 
cardium is incised and the following instrumen- 
tation implanted. The specific characteristics 
and care of each device will be discussed subse- 
quently. 
Instrumentation (see Figure 1). (a) A Teflon 
catheter (#8F with length fixed at surgery) 
was inserted via the internal mammary artery 
and advanced to the central aortic region (bra- 
FiGUKE 1. — Diagrammatic representation of instru- 
mented calf heart. Included are aortic root flow 
probe (AoQ) ; left main (LM) and left anterior de- 
scending (LAD) flow probes; and left anterior de- 
scending and left circumflex (LC) occluders. In ad- 
dition, left ventricular pressure transducer cable 
(LFP), and brachiocephalic pressure catheter (AP) 
are shown. (Printed with permission of the author 
from "Left ventricular failure and cardiogenic shock 
following acute myocardial infarction: A correlation 
of clinical and experimental observations." Confer- 
ence on Research Animals in Medicine, 1972.) 
