Brack A. Bivins

Patient-controlled analgesia: a new concept of postoperative pain relief.

This report concerns evaluation of patient-controlled analgesia (PCA) in the form of two preliminary investigations. In the first study, the patient-controlled analgesia device, which consists of a pump linked to a timer so that patients can activate intravenous administration of morphine sulfate to themselves during the postoperative period, was used in seven morbidly obese patients. The amount of morphine used during the first 36 hours was found to vary between 32 and 185 mg, with a significant difference in drug usage when related to weight as well as to body surface area. In the second study, morbidly obese patients undergoing gastric bypass operations were prospectively randomized into 12 patients who used the PCA device in the postoperative period and 12 patients who were given standard intramuscular dosages of morphine sulfate. An analgesia and sedation scale was then used to compare the two groups. The patients in the PCA group were able to maintain a state of adequate analgesia without sleep with a significantly greater frequency than were those in the intramuscular injection group. On the basis of answers to a questionnaire given to the patient after 60 hours of morphine analgesia, it was apparent that the PCA group was much more satisfied with that form of postoperative analgesia. It would appear that PCA is an efficacious and safe method of providing for postoperative pain relief.

High Protein Enteral Feedings: A Means of Achieving Positive Nitrogen Balance in Head Injured Patients

In an attempt to improve early enteral nitrogen replacement, nitrogen status was compared in two groups of head injured patients receiving enteral regimens of 38 to 51 kcal/kg/day with different protein concentrations. Eleven control patients received 1.5 g protein/kg/day and 10 study patients received 2.2 g protein/kg/day. Daily nitrogen excretion, corrected nitrogen balance, blood urea nitrogen changes, and enteral formula tolerance were compared between groups over a 10-day period. Those receiving 2.2 g protein/kg/day had significantly higher daily and cumulative nitrogen balances despite their higher nitrogen excretion levels. Over 10 days, the study group retained 9.2 g nitrogen. By comparison, the control group sustained a cumulative loss of 31.2 g nitrogen over 10 days, despite a mean intake of 109 g protein/day. In both groups, full strength, full rate feedings were not possible until day 10 postinjury. These data indicate that once enteral formulas are tolerated high nitrogen regimens are required to achieve positive nitrogen balance in acute severe head injury patients.

Coagulopathy and Intraoperative Blood Salvage (ibs)

The use of potentially contaminated shed blood and the contribution of autotransfused blood to coagulopathy are controversial issues associated with intraoperative blood salvage (IBS) in trauma patients. Intraoperative blood salvage was used in 154 trauma patients and resulted in reinfusion of 7.97 units per patient. Moderate to severe abnormalities of the prothrombin time (PT) and partial thromboplastin time (PTT) occurred in 39 patients (31%). Prolongation of the PT and PTT occurred with increasing transfusion. Coagulopathy was seen in patients receiving greater than 15 IBS units and in patients receiving greater than 50 combined units of blood. Of the 66 patients with bowel injury, 58 patients received shed blood. Patients with bowel injury showed no increase in infection but did develop prolongation of PT and PTT at lower levels of IBS transfusion. Based on the results of this study, patients receiving greater than 15 units of IBS transfusion require careful monitoring and factor replacement, and IBS transfusion should be limited to less than 10 units in patients with bowel injury.

Carcinoembryonic antigen (CEA) levels and tumor histology in colon cancer.

The demonstration of a tumor specific antigen (carcinoembryonic antigen) in 1965 raised the hope that the long-sought after “blood test for cancer” had been found [ 11, 121. Early optimistic reports suggested that the serum carcinoembryonic antigen (CEA) would be elevated or positive in as high as 90% of patients with colon cancer [9,24,27]. This original promise of CEA has not been fulfilled due to (1) a high incidence of false negatives in early lesions, (2) positive titers associated with malignancies outside the G.I. tract, (3) a significant number of false positives in patients with benign inflammatory disease [6, 9, 16, 20, 231. Despite these shortcomings, the CEA titer is elevated in over 70% of patients with carcinoma of the colon [5, 20, 251. During the past 5 years many investigators have tried to assess the role of CEA in cancer diagnosis, management and prognosis [2,20,21]. A number of studies have shown the plasma CEA may not be directly related to the size and extent of the colon cancer [ 1, 16,261. Recently we posed the question: Is the tumor associated with a high CEA titer histologically different from the tumor associated with a low CEA titer? In this study an attempt is made to answer that question by examining independently tumor

Pancreatic Exocrine Response to Parenteral Nutrition

Animal experimental data concerning pancreatic exocrine secretory response to parenteral nutrition is contradictory. We have studied the pancreatic exocrine output in a patient with a pure pancreatic fistula. In this patient, parenteral nutrition with hypertonic glucose, amino acids and fat emulsion was not associated with increases in fistula volume or protein output. Enteral protein and fat in this patient caused rapid increases in both fistula volume and protein output. This study supports the use of parenteral nutrition as a means of maintaining the pancreas at rest.

The Influence of Dose Frequency and Agent Toxicity on the Cost of Parenteral Antibiotic Therapy

The influence of the number of daily doses on the overall cost of antibiotic therapy is examined in a general surgery patient population. Patients receiving a single first-generation cephalosporin are compared with patients receiving two or three antibiotics (including an aminoglycoside) in terms of (1) the cost of the drug and the supplies, (2) time required for nursing and pharmacy personnel to prepare and administer the doses, and (3) the influence of agent toxicity (renal function) on physician-ordered laboratory tests. On the whole, combination therapy including an aminoglycoside was four times as expensive as single-agent (first-generation cephalosporin) therapy. If future studies demonstrate that single-agent antibiotic therapy is as effective as traditional combination therapy for specific infectious diseases, the influence of the number of daily doses of drug and agent toxicity may support the cost-effective use of the newer agents.

Parenteral safflower oil emulsion (Liposyn 10%): safety and effectiveness in treating or preventing essential fatty acid deficiency in surgical patients.

The safety and effectiveness of a 10% safflower oil emulsion in treating or preventing essential fatty acid deficiency was tested in a prospective study of 15 surgical patients requiring total parenteral nutrition for two to four weeks. Three dosage regimens were evaluated including: Group I: 4% of calories as linoleate daily (five patients), Group II: 4% of calories as linoleate every other day (two patients), and Group III: 8% of calories every other day (eight patients). Patients were monitored for laboratory changes from baseline specifically in those areas where previous fat emulsions have caused serious deviations. No significant changes were noted in hematologie parameters, coagulation studies, cholesterol and triglyceride serum levels. Although there were sporadic mild deviations in liver function changes in several patients, no clinically significant adverse effects could be directly attributed to infusion of the fat emulsion. Three patients had baseline triene/tetraene ratios of 0.4 or greater, indicative of essential fatty acid deficiency, and these ratios dropped to less than 0.4 within eight days of beginning therapy with the parenteral fat emulsion. The remaining 12 patients maintained a normal triene/tetraene ratio of less than 0.4 throughout the 28 day study period. All three dosage regimens were considered effective for treatment and prevention of essential fatty acid deficiency.

Inflammatory potential of foreign particulates in parenteral drugs.

Particulate and bacterial contamination of IV fluids and drugs have been implicated in venous thrombosis, infusion phlebitis, suppurative thrombophlebitis, pyrogenic reactions, and systemic sepsis. In a study of the inflammatory potential of the filterable residue of sodium cephalothin, we have found a tissue-specific reaction with venous endothelium but not with cutaneous or subcutaneous tissues. In a controlled animal model, removal of particulates from an infusion by use of a 0.45 μ in-line membrane filter reduces the incidence and severity of infusion phlebitis.

Patient-Controlled Analgesia: A Review of Effectiveness of Therapy and an Evaluation of Currently Available Devices

Patient-controlled analgesia (PCA) is a major advance in the management of pain in postoperative and cancer patients. The success of PCA has resulted in a proliferation of marketed devices to administer small bolus doses of parenteral pain-control drugs at fixed intervals controlled by the patient with the push of a button. Because patients demonstrate marked individual variation in pain medication requirements, PCA devices should be able to accommodate rapidly changing requirements for drugs with a minimum amount of effort on behalf of health care personnel. Crude electronic devices were developed in the late 1960s and the early 1970s and usually consisted of a syringe pump connected to some sort of timing device. Most modern PCA devices marketed in the past five years are much more sophisticated devices that are microprocessor based and some newer devices even generate hard copy for a permanent record of drug administration. Although many such devices are available (including a totally disposable PCA device), few have undergone extensive clinical evaluation. A review of the literature shows many devices are available for use without a single publication to document the safety and utility of the device in the routine patient care situation. Use of the PCA method of pain control will grow, and all hospital-based health care personnel should become familiar with their use and limitations.

Failure of nonprotein calories to mediate protein conservation in brain-injured patients.

Nitrogen balance in response to varying caloric intake was studied in 17 non-steroid-treated patients with isolated severe head injury (Glasgow Coma Scores, 4-9). Nitrogen excretion was found to remain relatively stable or to rise in response to protein intake over a wide range of nonprotein calorie intakes. Urine urea nitrogen excretion was not related to caloric intake, but was correlated (p less than 0.04) with nitrogen intake. In this study protein conservation was not achieved by increasing caloric intake up to and beyond two times the basal energy expenditure in the brain-injured patient. In these patients nitrogen balance could only be achieved by nitrogen intakes in excess of the high protein catabolic rate. These findings argue for a central control mechanism for protein catabolism that is independent of the magnitude of peripheral tissue injury.Nitrogen balance in response to varying caloric intake was studied in 17 non-steroid-treated patients with isolated severe head injury (Glasgow Coma Scores, 4-9). Nitrogen excretion was found to remain relatively stable or to rise in response to protein intake over a wide range of nonprotein calorie intakes. Urine urea nitrogen excretion was not related to caloric intake, but was correlated (p less than 0.04) with nitrogen intake. In this study protein conservation was not achieved by increasing caloric intake up to and beyond two times the basal energy expenditure in the brain-injured patient. In these patients nitrogen balance could only be achieved by nitrogen intakes in excess of the high protein catabolic rate. These findings argue for a central control mechanism for protein catabolism that is independent of the magnitude of peripheral tissue injury.