Effect of dopamine infusion (3-30 microg/kg/min) on hepatic hemodynamics.

BACKGROUND: While dopamine produces well-characterized dose-dependent effects on systemic hemodynamics, there is a paucity of information regarding its effects on hepatic hemodynamics. Infusion rates above 10 microg/kg/min are reported to produce significant vasoconstriction and impair organ perfusion. Therefore, donors are sometimes considered unsuitable when higher doses of dopamine are in use. The aim of this study was to determine the effect of increasing doses of dopamine on hepatic hemodynamics in a nonanesthetized swine model. MATERIALS AND METHODS: Sixteen pigs were instrumented with indwelling catheters in a peripheral artery, peripheral vein, portal vein, and hepatic vein and flow probes around the portal vein and hepatic artery. After recovery, the following variables were measured 10 +/- 1 days postinstrumentation: hepatic arterial flow (HAF), portal venous flow (PVF), mean systemic arterial pressure (MAP), central venous pressure (CVP), portal venous pressure (PVP), hepatic venous pressure (HVP), heart rate (HR). Recordings were obtained at baseline and subsequently when dopamine was infused at rates of 3, 6, 12, 15, 21, and 30 microg/kg/min increasing at 1-h intervals. RESULTS: HAF and PVF increased linearly over the entire infusion range, to 69 and 13% over baseline, respectively (P < 0.001, P < 0.05). Total hepatic blood flow rose 23% over baseline at the 30 microg/kg/min dosage (P < 0.01). MAP increased linearly 13% over the range 12 to 30 microg/kg/min (P < 0.001). CVP, HVP, and PVP did not change significantly. HR decreased from 12 to 15 microg/kg/min (P < 0.01), then increased from 15 to 30 microg/kg/min (P < 0.05). CONCLUSION: These data show that dopamine infused at dosages of 3-30 microg/kg/min augments HAF, PVF, and THBF and that this effect is linear. These results suggest high-dose dopamine infusion does not disqualify a potential donor liver for transplantation.

A model for the extended studies of hepatic hemodynamics and metabolism in swine.

To our knowledge postoperative hepatic hemodynamics and hepatic metabolism have not been fully studied on a long-term basis. Our goal was to develop a large animal model that would permit the measurement of hepatic blood flow (BF), perihepatic pressures (P), and hepatic metabolism in a long-term setting. Catheters were inserted into the jugular vein, carotid artery, pulmonary artery, hepatic vein, and portal vein (PV) of 27 commercially bred pigs; ultrasonic transit time flowmeter probes were placed around the hepatic artery and PV. Daily postoperative measurements of jugular vein P, carotid artery P, pulmonary artery P, hepatic vein P, and PVP, as well as hepatic artery BF and PVBF, were recorded for 20 days. Hepatic carbohydrate metabolism was assessed by arteriovenous difference techniques. Jugular vein P, pulmonary artery P, hepatic vein P, PVP, and heart rate reached steady-state values during the first week, with a mean +/- SEM of 1.0 +/- 0.3 mm Hg for jugular vein P, 21.4 +/- 2.1 mm Hg for pulmonary artery P, 4.3 +/- 0.4 mm Hg for HVP, 7.8 +/- 0.5 mm Hg for PVP, and 116 +/- 4 beats per minute for heart rate. Mean carotid artery P increased from 65 +/- 3 mm Hg during surgery to 94 +/- 2 mm Hg on postoperative day 1 (P < 0.001) and to a mean 101 +/- 2 mm Hg thereafter. Total hepatic BF reached a steady-state value of 1,132 +/- 187 ml/min by postoperative day 7 (P = 0.19). Over week 1 hepatic artery BF measured as a percentage of total hepatic BF decreased from 35.0 +/- 3.0% to 15.5 +/- 2.7%, and PVBF increased from 65.0 +/- 3.0% to 84.5 +/- 2.7% (P < 0.005); both variables were steady thereafter. In the hemodynamic steady state the net hepatic balances of glucose, lactate, glycerol, and alanine in 5 pigs were 9.9 +/- 4.0, -4.2 +/- 0.4, -2.3 +/- 1.1, and -0.68 +/- 0.22 micromol/kg per min respectively. The net gut (portal-drained viscera) balances of glucose, lactate, alanine, and glycerol were -2.0 +/- 2.5, 1.1 +/- 0.5, 0.73 +/- 0.18, and -0.69 +/- 0.19 micromol/kg per min respectively. Thus, a reliable large animal model was developed to study acute and chronic hepatic hemodynamics and metabolism.

Freezing Points and Milk Adulteration.

The freezing point study of raw and retail milk samples as reported in the Journal of Milk and Food Technology (July, 1976) has continued for retail samples. The Pennsylvania Department of Agriculture adopted a regulation which considers milk with a freezing point of above -0.525 C to be adulterated. A list of causes of added water was prepared and distributed to producer and processor groups in Pennsylvania.

Handling Perishable Foods.

Food service industry management has been interested in help to meet sanitary regulations, reduce food spoilage, lengthen keeping quality, and prevent foodborne illness. Materials were developed for 1-day workshops to provide practical suggestions for handling perishable and preserved foods. Products included were meats, poultry and eggs, milk and dairy products, delicatessen, fruits, vegetables and seafood. A 200-page reference book and 12 sets of slides or filmstrips were used to outline spoilage, food poisoning, personal hygiene, equipment sanitation, and proper food handling practices. A program has been conducted at 16 locations in Pennsylvania. Participants have been supervisors from stores, schools, hospitals, nursing homes, restaurants, vending companies, and fast food operations. Educational materials and programs will train food service personnel how to handle perishable foods.