Evaluation of the predictive performance of nutritional indicators by receiver-operating characteristic curve analysis

Four hundred twenty-two cancer patients who underwent major surgery were studied. At admission, nutritional status was evaluated in all patients by assessing serum albumin (SA), total iron-binding capacity (TIBC), total lymphocyte count (TLC), serum cholinesterase activity (CHE), and weight loss (WL). All patients received perioperative short-term antibiotic prophylaxis and postoperative total parenteral nutrition. Prognostic ability of nutritional indicators was assessed by receiver-operating characteristic (ROC) curve analysis. The area beneath the ROC curve (Az) is an index of predictor performance when its value ranges from 0.5 (chance performance) to 1 (perfect prediction). Specificity, sensitivity, Youden index, and predictive values were determined for each nutritional parameter within a wide range of potential threshold values. Postoperative septic complications were observed in 85 (20.14%) patients. The Az values for the considered nutritional parameters ranged from 0.52 to 0.57 and that showed the low predictive ability of the parameters. When sensitivity and specificity for each nutritional parameter were examined at different thresholds, a clearly more predictive cutpoint was not observed, but ranges of values with a similar predictivity were observed. Significant ranges of predictivity were found for SA (33 to 35 g/L), for TIBC (2200 to 2300 micrograms/L), for TLC (2100 to 2200 million/L), for CHE (1700 to 1900 U/L), and for WL (7% to 12%). The higher values of Youden index were as follows: 1.183 for WL (cutoff 11%), 1.150 for TLC (cutoff 2100 million/L), and 1.145 for SA (cutoff 35 g/L). In conclusion, ROC curve analysis showed that the nutritional parameters had a low predictive ability.(ABSTRACT TRUNCATED AT 250 WORDS)

Distribution and survival of Escherichia coli translocating from the intestine after thermal injury

The present investigation was performed to study the kinetics of tissue distribution and deposition of Escherichia coli and endotoxin translocating from the intestine after thermal injury. Escherichia coli was grown in the presence of 14C glucose and both labeled bacteria and endotoxin prepared from the labeled bacteria were used as translocation probes. Escherichia coli (10(8) to 10(10) bacteria) and E. coli endotoxin (100 micrograms per animal) were gavaged into the stomach immediately before a 30% burn injury was inflicted in mice. Animals were killed 1, 4 and 24 hours after burn injury. Translocation occurred extensively within 1 hour after burn injury. Expressed as amount of radioactivity per gram of tissue, translocation was greatest in the mesenteric lymph node (MLN) followed by spleen, lung, and liver. Translocation of endotoxin was similar to translocation of intact bacteria, with the exception that less radioactivity could be found in the peritoneal cavity and more in the liver. Both intact E. coli and endotoxin translocated directly through the intact bowel wall. Killing of bacteria was greatest in the MLN and spleen, approximating 95% to more than 99% of translocating bacteria. Killing efficiency was lowest in the lungs. It is concluded that estimation of translocation by viable bacterial counts in tissues grossly underestimates the extent of translocation of bacteria and ignores the extent of translocation of endotoxin. Translocation of endotoxin may have biologic significance that is independent of and in addition to translocation of intact bacteria.

Effectiveness of perioperative short-term antibiotic prophylaxis in reducing surgical risk induced by malnutrition and anergy

The ability of perioperative short-term antibiotic prophylaxis to reduce the predictive significance of nutritional indicators for postoperative infections was evaluated in 162 patients undergoing major surgery for gastric or colorectal cancer. All patients were randomly assigned to a group receiving such prophylaxis or a group with postoperative antibiotic treatment. Preoperative serum albumin, total iron-binding capacity and weight loss were the nutritional indicators, and the evaluation included delayed hypersensitivity response. Postoperative infections occurred in 29% of the total series, with highest incidence in the group with postoperative antibiotics (p less than 0.001) and in anergic patients (p less than 0.05). Increased risk of postoperative infection was related also to the number of altered nutritional indicators (p less than 0.005). Multiple logistic analyses showed that the short-term prophylaxis independently contributed to fall in the infection rate and reduced the prognostic importance of nutritional and immunologic factors. Indeed, heightened incidence of postoperative infection was found only when all three nutritional factors were altered.

The process of microbial translocation

The process of microbial translocation was studied using Candida albicans, Escherichia coli, or endotoxin instilled into Thiry-Vella loops of thermally injured guinea pigs and rats. Translocation of C. albicans occurred by direct penetration of enterocytes by a unique process different from classical phagocytosis. Translocation between enterocytes was not observed. Internalization was associated with a disturbance of the plasma membrane and brush border, but most internalized organisms were not surrounded by a plasma membrane. Passage of the candida into the lamina propria appeared to be associated with disruption of the basal membrane with extrusion of cytoplasm of the cell and candida. Organisms in the lamina propria were commonly phagocytized by macrophages but also were found free in lymphatics and blood vessels. Translocation of E. coli and endotoxin also occurred directly through enterocytes rather than between them, but translocated endotoxin diffused through the lamina propria and muscular wall of the bowel wall by passing between rather than through the myocytes. These descriptive phenomena provide new insight into the role of the enterocyte and intestinal immune cells in the translocation process.

Prognostic ability of nutritional assessment methods in surgical cancer patients

To identify patients at high-risk for post-operative infections, several methods have been proposed, including prognostic nutritional index (PNI), instant nutritional assessment (INA) and nutritional assessment (NA). Weight loss (WL) has also been related to post-operative morbidity. We have evaluated the prognostic ability of PNI, INA, NA and WL in a prospective study carried out in 94 patients affected by gastro-intestinal malignancy, who underwent major surgery. Post-operative infections occurred in 26 (27.7%) patients. PNI, INA and NA identified classes of patients with a progressive risk of septic complications. To determine the prognostic ability of PNI, INA, NA and WL, sensitivity, specificity, Youden index and predictive values were evaluated. All methods had a Youden index greater than one, with a positive predictive value ranging from 0.33 to 0.36. Since all the methods studied showed a similar predictive ability, it seems reasonable to identify the high-risk surgical patient by using weight loss in association with those nutritional parameters derived from routine hospital laboratory tests.

Vasodilators and primary pulmonary hypertension. Variability of long-term response

Long-term response to vasodilator therapy was assessed in six patients with PPH. Following an acute trial, each patient was restudied after (1) two months of drug administration, (2) one month of abstinence from therapy, and (3) an additional two months of therapy. Three of six patients had no long-term reduction of PVR after treatment; one showed a progressive increase. Of the three patients whose PVR was still reduced at the end of the second therapy period none showed a return of PVR to baseline during the abstinence phase, which may suggest that long-term reduction of pulmonary vascular tone may modify the vasoconstrictive component of this disease. The heterogeneous response of this small number of patients to sequential drug administration and withdrawal demonstrates the difficulty of interpreting previously reported clinical trials and underscores the need for a well-designed controlled study of vasodilator administration in these patients.

Comparison of sustained-release theophylline scheduled conventionally (twice-daily, equal interval in equal amount) versus once-daily mornings or evenings on circadian pattern of bronchial patency in asthmatics

The effects of differently timed, but equivalent TheoDur (Key Pharmaceutical Co.) dosage schedules--twice-daily equally divided 12 hr (BID), once-daily evening (OD-PM) and once-daily morning (OD-AM)--were compared under steady-state conditions in 10 adult asthmatics with a documented history of nocturnal dyspnea. Assessments of airways function by spirometry were done every 3-hr over one complete 24-hr dosing interval for each dosage schedule under carefully controlled conditions. The different TheoDur regimens did not affect the 24-hr group average FEV1.0, PEF, MMEF or FVC. However, statistically significant circadian variation in airways function existed irrespective of the drug dosing schedule. Airways patency and FVC were least overnight (0200-0500 hr) and best during the morning or afternoon. With regard to FEV1.0 and PEF, which evidenced group circadian change for BID and OD-PM regimen by Cosinor analysis, the peak-to-trough (double amplitude) difference expressed as a percentage of the 24-hr average was rather large, being greatest for the OD-PM schedule (20.5% for FEV1.0 and 24.3% for PEF). The data for the 10 participants revealed individual differences in the effectiveness of the 3 studied theophylline dosing regimens when assessed in terms of the mean level and stability of airways function over the 24 hr. Based on the findings, neither the BID, OD-PM nor the OD-AM regimen effectively moderated the nocturnal deterioration of pulmonary function suggesting theophylline as dosed and timed may not be as efficacious as desired for patients with a history of strictly nighttime dyspnea. Thus, the schedule and prescription of TheoDur must take into account differences between patients, including the time when asthma symptoms are most likely to be experienced by each.

Noninvasive assessment of hemodynamic improvement during chronic vasodilator therapy in obliterative pulmonary hypertension

The ability to treat selected patients with obliterative pulmonary hypertension (OPH) with vasodilator therapy has been clearly demonstrated. However, the dangers involved in their use in patients who fail to have a beneficial response have also been well documented. A major problem in the management of these patients has been the lack of an easily measurable, noninvasive index of alterations in cardiopulmonary status that could be used at relatively frequent intervals to monitor the response to therapy. We have studied the utility of changes in noninvasively assessed exercise performance to predict changes in pulmonary vascular tone. In 10 patients with OPH, we compared symptom-limited oxygen consumption (Vo2ex) and oxygen pulse (Vo2/heart rate) at Vo2ex (O2 Pex) determined during progressive treadmill exercise with invasive measurements of cardiovascular function during steady-state supine bicycle submaximal exercise prior to and 8 wk after initiation of vasodilator therapy with nifedipine or diltiazem. After vasodilator therapy, total pulmonary vascular resistance decreased at rest and during exercise in 6 patients. At the same time, changes in Vo2ex ranged from -33 to 47% and in O2Pex from -26 to 57%. There was an excellent relationship between the magnitude of the change in exercise and resting total pulmonary vascular resistance and the change in both Vo2ex and O2Pex. We suggest that changes in Vo2ex and O2Pex may be a useful means of following the ability of vasodilators to improve cardiovascular function in patients with OPH.

Further studies on the hypernoradrenergic state of treated hypertensives: effect of captopril

We investigated the effect of captopril on plasma norepinephrine concentration and blood pressure in two groups of hypertensive patients. One group consisted of five severely hypertensive patients rendered hypernoradrenergic by administration of a minoxidil-propranolol-diuretic regimen. The other group was ten untreated mildly hypertensive patients. Two hours after 12.5mg of captopril, blood pressure was lowered (p less than .05) in four of the five hypernoradrenergic patients from 180 +/- 8/102 +/- 8 to 132 +/- 7/77 +/- 8 mmHg. Chronic administration of 100-150mg of captopril tid caused no further blood pressure reduction. Precaptopril plasma norepinephrine concentration was 925 +/- 206 and two hours after the 12.5mg dose was 807 +/- 80 pg/ml. Three months later having advanced the dose to 300-450 mg/day it was lower (p less than .05) at 752 pg/ml. The acute blood pressure response correlated (r = -0.72, p less than .001) with the precaptopril plasma norepinephrine. Precaptopril blood pressure in the mild hypertensive patients was 146 +/- 4/98 +/- 1, after a 25-100mg dose it was 137 +/- 6/91 +/- 2 (diastolic p less than .05) and at two months with the same captopril dose bid it was 141 +/- 8/88 +/- 4 mmHg (diastolic p less than .01). Corresponding initial PNE was 425 +/- 72, two hours after captopril 405 +/- 47 and 310 +/- 63 pg/ml (p less than .05) with chronic administration. Thus, captopril lowers blood pressure in both hypernoradrenergic and eunoradrenergic hypertensive patients without increasing plasma norepinephrine suggesting some unique dampening effect of this drug on the sympathetic nervous system. Also, addition of captopril to triple therapy lowered blood pressure in proportion to plasma norepinephrine levels suggesting importance to its action on this sympathetic nervous system effector.