Comparison of Hemodynamic and Oxygen Transport Effects of Dopamine and Dobutamine in Critically Ill Surgical Patients: Materials and Methods

Comparison of Hemodynamic and Oxygen Transport Effects of Dopamine and Dobutamine in Critically Ill Surgical Patients: Materials and MethodsClinical Series
The study was approved by the institutions Human Subjects Review Committee, and each patient or the next of kin signed an informed consent. Studies were performed on 25 critically ill general surgical patients; Table 1 summarizes the salient clinical features. Each patient was given dopamine and dobutamine; the allocation of the first drug was by randomized order; subsequently, the other drug was given. Each drug was given in dosages of 2.5μg/kg/min, 5μg/kg/min, 7.5μg/kg/min, and 10μg/kg/min as tolerated. A minimum of 30 minutes and a maximum of two hours was allowed for equilibration between doses; post-trial baseline values were obtained 30 minutes after discontinuance of the last dose in each trial. Therapy with the drug was stopped if the HR increased over 140 beats per minute or the arterial pressure increased or fell inappropriately (>20 mm Hg). Data from the 16 patients who were studied in the immediate (0 to 72 hours) postoperative period were compared with the data from nine patients studied in later stages; the latter group also had complications such as sepsis, respiratory failure, renal failure, or other problems contributing to their critical illness and delayed recovery.

Physiologic Measurements
We measured MAP, MPAP, CVP, PAWP, HR, cardiac output, arterial and mixed-venous blood gas levels, pH, oxyhemoglobin saturations, hematocrit reading, and core temperature. Calculations of LVSW, RVSW, LCW, RCW, SVRI, PVRI, Doa, Vo2, oxygen extraction, and Qsp/Qt were derived by standard formulas. All measurements of flow and volume were indexed by dividing by body surface area.
After one or two complete sets of measurements were obtained during a control period, patients were selected for study if they had not attained optimal therapeutic goals previously defined for high-risk postoperative patients. Then either dopamine or dobutamine was selected by a prearranged random-number table as the first agent to be given. Therapy with the drug was started at 2.5μg/kg/ min as a constant infusion, and after approximately 30 minutes of infusion, another complete set of measurements was taken. The dosage was increased to 5.0μg/kg/min, and after 20 to 30 minutes, an additional set of measurements was taken. Again, if blood pressure and HR were acceptable, dosages of 7.5μg/kg/min and subsequently 10μg/k^min were administered, and measurements again were obtained 20 to 30 minutes after each increase in dosage. The study was then repeated using the other drug; each patient received each drug in random order. At no time during these studies was fluid management, drug therapy, inspired oxygen concentration, or ventilatory settings changed. At least 30 minutes were allowed for equilibration between each change of dosage and between the last dose and the post-trial baseline measurements; stable baseline values were demonstrated for one to two hours before the second drug was started.
One patient given dobutamine had tachycardia with 7.5μg/kg/ min and four others with 10μg/kg/min; five patients given dopamine had hypertension with 5μg/kg/min, two others with 7.5μg/kg/min, and seven others with μg/kg/min.

Table 1—Clinical Data

Patient, Sex, Age (yr) Diagnosis* Operation AgentGivenFirst
1, F, 84 Fracture of femur; laceration of liver Open reduction; internal fixation Dopamine
2, M, 29 Multiple fractures of pelvis, bilateral femur; retroperitoneal hematoma Open reduction; internal fixation; exploratory laparotomy Dobutamine
3, M, 47 1st surgery: UGI bleed from duodenal ulcer; 2nd surgery: postoperative hemorrhage (1) Vagotomy, pyloroplasty, and suture ligation; (2) suture ligation of bleeder Dopamine
4, F, 44 Auto accident; perforated ileum Resection of ileal segment Dobutamine
5, M, 23 GSW of abdomen with perforated ileum; intrathoracic hemorrhage Exploratory laparotomy; ileal resection Dopamine
6, F, 84 Gangrene of foot Amputation Dobutamine
7, F, 95 Perforated peptic ulcer Repair of ulcer perforation Dobutamine
8, M, 25 GSW; hemothorax; laceration of diaphragm, pancreas, and jejunum Exploratory laparotomy; repair of jejunum, diaphragm, and pancreas Dopamine
9, M, 70 SW; laceration of stomach, duodenum, and gallbladder Exploratory laparotomy; repair of duodenum and stomach; cholecystectomy Dopamine
10, M, 36 GSW; neck; tracheal, and esophageal perforation Repair of trachea and esophagus Dopamine
11, F, 53 GSW; laceration of stomach; UGI bleeding Exploratory laparotomy; repair of gastric injury Dopamine
12, M, 20 GSW to abdomen; ileal perforation Exploratory laparotomy; resection of ileal segment Dobutamine
13, F, 58 Cholecystitis with cholelithiasis Exploratory laparotomy; cholecystectomy; common duct exploration; lysis of adhesions Dobutamine
14, F, 51 SW to abdomen; multiple ileal perforations Exploratory laparotomy; repair ileal lacerations Dobutamine
15, M, 53 Perforated diverticulitis Large-bowel resection; colostomy Dobutamine
16, M, 58 Pancreatic cancer Pancreatectomy (Whipple) Dobutamine
17, M, 63 Adenocarcinoma of esophagus Esophagogastrectomy Dopamine
18, F, 37 SW of chest and neck; cardiac tamponade Thoracotomy; neck exploration; pericardiotomy Dopamine
19, F, 41 Gangrenous gallbladder; ascending cholangitis Exploratory laparotomy; cholecystectomy; common duct exploration; T tube Dobutamine
20, F, 70 SW to chest, abdomen, and face; perforation of ileum and diaphragm Ileal resection; repair of diaphragm, right eye enucleation Dobutamine
21, M, 59 Perforation of duodenal ulcer Vagotomy; antrectomy Dopamine
22, M, 31 SGW; laceration of spleen, stomach, colon, ileus, and left kidney Exploratory laparotomy; repair of injuries Dopamine
23, F,86 Perforated, incarcerated inguinal hernia Exploratory laparotomy; repair of hernia Dobutamine
24, M, 34 Auto accident; liver laceration; cervical spine fracture Exploratory laparotomy; repair liver injury Dopamine
25, M, 57 1st surgery: spine fracture, necrotizing pancreatitis; 2nd surgery: wound dehiscence with perforation of ileum (1) Drainage of pancreas; (2) resection of ileal segment Dobutamine

Category: Surgical Patients

Tags: Cardiac Output, dobutamine, exploratory laparotomy, surgical patients