Operative site bacteriology as an indicator of postoperative infectious complications in elective colorectal surgery

Toward the completion of elective colorectal operations, 75 patients had qualitative aerobic and anaerobic cultures of specimens obtained from peritoneal irrigation fluid, anastomoses sites, and abdominal wound irrigation fluid to determine if a correlation exists between intraoperative flora and postoperative infectious complications. Patients enrolled in this prospective study received a mechanical bowel prep and a 12-18 hour course of perioperative intravenous antibiotics. Comparisons were made between the 60 (80%) patients who had no postoperative infections and the 15 (20%) who developed postoperative infectious complications (9 wound infections, 6 intraabdominal infections). There were significantly more low anterior resections in patients who developed postoperative infection compared to those who had no postoperative infection (26% vs 2%), while there were more colocolostomies in the group with no infections (38% vs 7%). Streptococcus spp., Bacteroides fragilis group, and Escherichia coli were the most commonly isolated organisms from each of the three sites sampled. Isolation of > or = 3 organisms from incisional wound cultures (P = 0.017) and < or = 4 organisms from peritoneal irrigation (P = 0.009) or anastomotic culture (P = 0.004) correlated with development of postoperative infectious complications. Thus, patients with infectious complications had significantly more isolates than those without infectious complications, and were more likely to have had a low anterior resection. These data suggest that future clinical studies should reexamine the duration of perioperative antimicrobials based on early laboratory reports of qualitative and quantitative operative site bacteriology.     

Right ventricular dysfunction in low output syndrome after cardiac operations: assessment by transesophageal echocardiography

BACKGROUND: Low output syndrome after cardiac operations is associated with high morbidity and mortality rates. The contribution of right ventricular dysfunction to this syndrome has not been fully characterized. The purpose of this study was to evaluate the utility of transesophageal echocardiography to identify the frequency and the in-hospital mortality from right ventricular dysfunction in patients with this syndrome. METHODS: Seventy-five consecutive patients undergoing transesophageal echocardiography for low output syndrome early after cardiac operations were evaluated. The findings from transesophageal echocardiography were correlated with the type of surgical procedure, cross-clamp time, right heart hemodynamics, and coronary angiography. RESULTS: Right ventricular systolic dysfunction occurred in 36 patients (42%); in 17 patients it was isolated and in 19 patients it occurred in combination with left ventricular dysfunction. Postoperative right ventricular dysfunction was not uniformly associated with important right coronary artery disease or with prolonged ischemic time during cardiopulmonary bypass. Hemodynamic data were not useful to distinguish the group with postoperative right ventricular dysfunction. Patients with right ventricular dysfunction had a high (44%) in-hospital mortality rate. CONCLUSIONS: Right ventricular dysfunction occurs frequently in patients with low output syndrome after cardiac operations and is associated with a high in-hospital mortality rate. Better understanding of the mechanisms causing postoperative right ventricular dysfunction may provide insight for preventing this complication.     

Recent Changes in the Near-Shore Phytoplankton of Lake Erie's Western Basin at Kingsville,Ontario

A weekly net phytoplankton monitoring programme begun in 1967 at the Union water treatment plant, Kingsville, Ontario, was expanded in 1976 to include weekly chemical analyses of western Lake Erie water samples. Data from the Union intake monitoring programme have been examined in light of the significant reductions, since 1971, in phosphorus loading from the Detroit River. Total phosphorus concentrations in the “raw water” declined to an average of 30-35 μg P/L during 1977-78 from a pre-P control average of 63 μg P/L during 1967-70. Average annual net phytoplankton density during the pre-P control years averaged about 5000 Areal Standard Units per mL (A.S.U./mL), decreased steadily between 1971 and 1976 to a low of 2900 A.S.U./mL, but then increased again to 4490 A.S.U./mL by 1978. The recent increase was attributed almost entirely to massive mid-summer development of Fragilaria crotonensis. Winter densities of net phytoplankton during 1977 and 1978 were the lowest on record for the 12-year period. Similarly, average densities of green and blue-green algae showed a pre-P control density regime which was clearly higher than the post 1971 densities. Annual average diatom density was negatively correlated with annual average lake levels over the 12-year period and recent anomalous increases in Fragilaria may have been related to the observed drop in lake level which influenced turbulence and resuspension of this diatom.     

Brain abscess and congenital heart disease

The clinical features and management of 18 patients with congenital heart disease and a brain abscess are reviewed. Except for one patient all had cyanosis. All abscesses were large, containing at least 50-60 ml of pus, and mostly unilocular. Bilocular and multilocular abscesses were also encountered. The organisms cultured from the pus had little relation to the mortality. Tapping may be the final investigation, and is also the treatment of choice. The high mortality (50%) is attributed to the delay in referral of these patients to a neurosurgical unit.     

Incorporation of 1,2-14C-ethanolamine into subfractions of rat liver phosphatidylethanolamines and phosphatidylcholines

The incorporation of 1,2-¹⁴C-ethanolamine into the liver phosphatidylethanolamines (PE) and phosphatidylcholines (PC) in female rats was studied. These phosphatides were fractionated according to their degrees of unsaturation and the specific activities of monoenoic, dienoic, tetraenoic and hexaenoic fractions were measured at intervals of 1, 20, 60 and 300 min after injection of the labeled precursor. Hexaenoic and dienoic PE incorporated and lost the label rapidly. Although the labeled precursor was incorporated into tetraene PE at a similar rate, this fraction attained a relatively low specific activity that remained essentially constant between 10 and 300 min after injection of the label. Hexaenoic PC had the highest specific activity among the PC fractions at all time periods. Estimations of the rate of loss of radioactivity in the hexaenoic PE fraction and its appearance in hexaenoic PC indicate that the docosahexaenoic acid is conserved, possibly by being reincorporated into PE after becoming a part of the hexaenoic PC species. The high rate of turnover of the hexaenoic PE also suggests that this fraction might have some special role in endogenous choline synthesis.     

Studies on the stress relaxation of polystyrenes in the rubbery-flow region

Relaxation modulus curves for narrow distribution and broad distribution polystyrenes are compared and the significant effect of molecular weight distribution on these curves is shown. An empirical three-parameter equation is shown to describe the stress relaxation behavior of narrow distribution polystyrenes. New data for high molecular weight, narrow distribution polystyrenes are presented and used to extend the applicability of previous quantitative relations for higher molecular weights. The stress relaxation technique is shown to be sensitive to the type of plasticizer used at low concentrations.     

Rating method for evaluating distribution-system odors compared with a control.

A new sensory method was developed and tested at a full-scale water treatment plant. The method evaluates changes in aesthetic water quality during transit in the distribution system. A paired comparison format is used to determine if the odor of a distribution-system sample is different from that of a control sample. The control sample represents the "ideal" water, such as treated water leaving the plant. The method can rapidly determine whether or not a problem exists in the distribution system, and, if one does exist, it allows for characterization of the problem. Over a three-month period a 4-member odor panel evaluated 118 distribution samples by this new procedure. Among the 118 samples tested, 39 samples yielded a consensus among the analysts as to the odor characteristics of the sample; 35 were rated "not different from the control" (about 90%), and only 4 were rated "different from control" (about 10%). The 79 samples for which no consensus was generated had only slight rating differences between analysts and for odor intensity. No taste-and-odor problems were reported by consumers during the time period for this study and the method indicated that no major odor problems existed in the distribution system.