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J M Bohnen

Publications and source records attributed to J M Bohnen.

36 records · Page 2Linked to original sources
PubMed1993

Antimicrobial prophylaxis for surgical wounds. Guidelines for clinical care.

Prophylactic administration of antibiotics can decrease postoperative morbidity, shorten hospitalization, and reduce the overall costs attributable to infections. Principles of prophylaxis include providing effective levels of antibiotics in the decisive interval, and, in most instances, limiting the course to intraoperative coverage only. Use in The National Research Council clean contaminated operations is appropriate and, in many instances, has been proven beneficial. Antibiotic prophylaxis is also indicated for clean operations, such as those involved with insertion of prosthetic devices, that are associated with low infection risk and high morbidity. Extension of antibiotic prophylaxis to other categories of clean wounds should be limited to patients with two or more risk factors established by criteria in the study of the efficacy of nosocomial infection control (SENIC) because the baseline infection rate in these patients is high enough to justify their use. Cefazolin (or cefoxitin when anaerobic coverage is necessary) remains the mainstay of prophylactic therapy. Selection of an alternate agent should be based on specific contraindications, local infection control surveillance data, and the results of clinical trials. Newer criteria for determining the risk of "site infection" (wound and intracavitary) are in evolution and may lead to modification of these recommendations over the next several years.

Anti-Bacterial Agents↗
PubMed1993

Distribution of free and liposome-encapsulated cefoxitin in experimental intra-abdominal sepsis in rats.

The distributions of radiolabelled free cefoxitin (FC) and liposome-encapsulated cefoxitin (LC) were compared in an animal model of intra-abdominal sepsis. Intraperitoneally administered LC was initially retained in the peritoneal cavity with subsequent preferential drug targeting to the liver (14% injected LC) and spleen (6% injected LC) by 3 h post-injection. Differing patterns of liposomal drug and lipid retention indicated that drug release from the liposome complex occurred within the peritoneum, liver and spleen. Intraperitoneal FC was rapidly taken up into the systemic circulation, with peak recovery in the blood (9% injected FC) and liver (5% injected FC) at 1 h post-injection. FC was also rapidly eliminated; 7% of the injected drug was recovered in the kidney 1 h post-injection. A negligible amount of FC was recovered in the spleen and very little FC or LC was found in the lungs of treated animals. Unlike FC, LC was found to provide a sustained bactericidal drug level (> 40 micrograms mL-1) in the peritoneal fluid for up to 5 h post-injection. LC also achieved significantly higher drug levels, compared with FC, within the liver at 3 and 5 h post-injection. Since severe intra-abdominal sepsis is often characterized by the presence of intraphagocytic bacteria in hepatic and splenic reticuloendothelial systems, the enhanced delivery of liposome-encapsulated anti-microbial agents, such as cefoxitin, to the liver and spleen may provide a more effective treatment for the septic condition.

Abdomen↗
PubMed1992

Guidelines for clinical care: anti-infective agents for intra-abdominal infection. A Surgical Infection Society policy statement.

Several antibiotics have been marketed for therapeutic use in intra-abdominal infection. Often, these agents do not provide a sufficient spectrum activity against both facultative and obligate anaerobic gram-negative organisms, or have certain toxic effects that would not otherwise support their use. Guidelines have been developed for selection of antibiotic therapy for intra-abdominal infections and are presented as a statement of the Surgical Infection Society endorsed by the Executive Council. These guidelines are restricted to infections derived from the gastrointestinal tract and deal with those microorganisms commonly seen in such infections. The recommendations are based on in vitro activity against enteric bacteria, experience in animal models, and documented efficacy in clinical trials. Other concerns regarding pharmacokinetics, mechanisms of action, microbial resistance, and safety were also used in the formation of these guidelines. For community-acquired infections of mild to moderate severity, single-agent therapy with cefoxitin, cefotetan, or cefmetazole or ticarcillin-clavulanic acid is recommended. For more severe infections, single-agent therapy with carbapenems (imipenem/cilastatin) or combination therapy with either a third-generation cephalosporin, a monobactam (aztreonam), or an aminoglycoside plus clindamycin or metronidazole is recommended. Regimens with little or no activity against facultative gram-negative rods or anaerobic gram-negative rods are not considered acceptable.

Abdomen↗
PubMed1992

Operative management of intra-abdominal infections.

Operation for intra-abdominal infection aims to prevent further contamination of the abdominal cavity, treat the underlying source of infection, and prevent residual or recurrent sepsis by cleaning the peritoneal cavity. Aggressive attempts at early diagnosis are warranted, even if laparotomy is occasionally required for diagnostic as well as therapeutic purposes. Conversely, the degree to which more aggressive methods of peritoneal debridement are helpful is the subject of great controversy that can be resolved only by prospective, randomized multicenter trials. Current standard treatment consists of closure, drainage, or excision of the source of contamination; intra-operative saline or antibiotic lavage of the peritoneal cavity; fascial closure; and secondary or delayed primary closure of the wound.

Abdomen↗
PubMed1991

Pneumonia complicating abdominal sepsis. An independent risk factor for mortality.

Nosocomial pneumonia (NP) is associated with a significant mortality, 66% in a previous retrospective study of NP complicating intra-abdominal sepsis (IAS). We prospectively compared the outcome of NP complicating IAS with that of recurrent IAS (R-IAS) in the absence of NP. Data were collected prospectively on 300 patients with IAS; 34 patients who presented with pneumonia were excluded from the analysis (44% mortality). One hundred seventy-one patients with no NP and no R-IAS (group 1) had a hospital mortality of 20% (34 patients); 36 without NP in whom R-IAS developed (group 2) had a 17% mortality (six patients); and 47 with NP but no R-IAS (group 3) had a 53% mortality (25 patients). Finally, 12 patients who had both NP and R-IAS suffered a 75% mortality (nine patients). We examined the relationships among the following putative risk factors and mortality: APACHE (acute physiology and chronic health evaluation) II score (at initial presentation with IAS), the need for mechanical ventilatory assistance following initial treatment for peritonitis, steroid requirement, generalized peritonitis vs abscess, and the need for surgical as opposed to percutaneous treatment. Using mortality as the dependent variable, group 2 vs 3 as the explanatory variable, and the risk factors as confounders, logistic regression analysis indicated that the group difference was significant after controlling for confounders. We conclude that NP complicating IAS is an independent risk factor associated with a significant mortality compared with R-IAS. These data challenge the notion that death in IAS is usually due to recurrent or persistent intra-abdominal infection.

Abdomen↗
PubMed1991

Antimicrobial prophylaxis in general surgery.

When used appropriately, antimicrobial prophylaxis is highly beneficial and cost effective. Antibiotics are not indicated for "clean procedures" such as hernia and breast surgery. A single preoperative dose will suffice, followed by an intraoperative dose if the operation takes more than 3 hours. For vascular (prosthesis or groin wound), head and neck (pharynx entered), thoracic (gastrointestinal or respiratory entrance) and high-risk gastroduodenal and biliary procedures, cefazolin, 1 g intravenously, is indicated. For procedures involving small intestine, appendix or penetrating abdominal trauma, cefoxitin or cefotetan, 2 g intravenously, is indicated. For colorectal procedures, either oral neomycin plus erythromycin or intravenous aminoglycoside plus clindamycin (or metronidazole) are effective. If valvular heart disease is present, endocarditis prophylaxis should be administered.

Anti-Bacterial Agents↗
PubMed1991

A critical look at scheduled relaparotomy for secondary bacterial peritonitis.

Scheduled relaparotomy is attracting interest as a means of treating intra-abdominal sepsis. It is the subject of several studies to evaluate its role in the management of peritoneal infection. However, indications for this procedure are not clear and current knowledge does not allow for adequate scientific evaluation. Many trials lack control groups and historical control groups cannot be evaluated on criteria, such as illness severity, concomitant health problems or even surgical technique. Indicators of outcome are generally described in insufficient detail; only death or survival are reported and important morbidity and resource utilization data are not included. A randomized, prospective, multicenter clinical trial using standardized techniques is necessary to determine the usefulness of scheduled relaparotomy performed on different patients.

Bacterial Infections↗
PubMed1989

Pathogenicity of enterococci in a rat model of fecal peritonitis.

The pathogenicity of enterococci in intraabdominal sepsis has not been clarified. Therefore, fecal-type peritonitis was induced in rats by intraperitoneal injection of barium sulfate along with a bacterial inoculum consisting of Escherichia coli, Bacteroides fragilis, and Clostridium perfringens with or without Streptococcus faecalis. Mortality at 19 d and characteristics of intraabdominal abscesses in survivors at 19 d were analyzed. The presence of S. faecalis in the original inoculum was significantly associated with death or large (greater than 20 mm) abscess formation when these two end points were examined together. S. faecalis may synergize with other bacteria in intraabdominal sepsis to augment morbidity and possibly mortality.

Abscess↗
PubMed1988

APACHE II score and abdominal sepsis. A prospective study.

Therapeutic trials for intra-abdominal sepsis require pretreatment stratification; physiologic scoring has been recently proposed for this purpose. We have prospectively tested the validity of one such scoring system, namely, the Acute Physiology and Chronic Health Evaluation (APACHE II). As part of a larger database, we correlated APACHE II scores with mortality in 100 patients hospitalized for generalized peritonitis or abdominal abscess. Use of steroids was recorded because of our suspicion that steroids increase mortality but blunt the physiologic response to sepsis. Thirty-one patients died, including 12 of 19 patients receiving steroids. Stepwise discriminant analysis revealed that the APACHE II score and steroid use were each independently associated with the rate of mortality. We report a prospective validation of pretreatment APACHE II scoring in abdominal sepsis. Steroid use is an independent risk factor.

Abscess↗
PubMed1988

Antibiotic efficacy in intraabdominal sepsis: a clinically relevant model.

We present preliminary data on the role of antibiotics in intraabdominal sepsis using a new, clinically relevant animal model. Peritoneal cavity infection was induced by ligation and perforation of the cecum in adult rats. Surviving rats were randomized to receive either saline or cefoxitin at the time of cecal excision and peritoneal lavage, 18 h after the onset of infection. This is different from previous models of abdominal sepsis (in which antibiotics are given within 4 h of peritoneal contamination) and mimics the clinical setting in which antibiotics are initiated much later, at the time of operation. Antibiotic-treated rats received 20 mg cefoxitin i.m. every 8 h for 7 days; controls received saline at similar times. Thirty-nine of 67 control rats died (58%) versus 20 of 64 (31%) that received cefoxitin (p less than 0.005). We conclude that even with delayed administration, antibiotics appear to improve the outcome of intraabdominal sepsis. With further characterization of this model we plan to use it as an in vivo assay to compare the efficacy of different antimicrobial agents in intraabdominal sepsis.

Animals↗
PubMed1987

C-reactive protein levels predict postoperative septic complications.

We studied 108 patients undergoing clean-contaminated and dirty surgical procedures to determine whether daily C-reactive protein (CRP) measurements for 14 days postoperatively could predict the occurrence of septic complications prior to clinical diagnosis. Diagnostic criteria for septic complications and positive CRP response were defined in advance of the study. The CRP assays were carried out using an automated laser nephelometer system after the patient's discharge from the hospital. Forty-six septic complications were diagnosed in 40 patients. These complications consisted of wound infection (23), urinary tract infection (11), pneumonia (six), upper respiratory tract infection (three), intra-abdominal abscess (one), and other (two). The CRP testing was found to have a positive predictive value of 69% and a negative predictive value of 78%. We conclude that serial CRP measurements may be a valuable adjunct to surgical care in patients at high risk of postoperative septic complications.

Adult↗
PubMed1987

Suppression of delayed cutaneous hypersensitivity and inflammatory cell delivery by sterile barium peritonitis.

We have previously shown that experimental peritonitis secondary to fecal bacteria plus barium sulfate suppresses delayed cutaneous hypersensitivity (DCH) in rats. We examined herein the role of barium sulfate. In a series of experiments presensitized rats were simultaneously skin tested with intradermal keyhole limpet hemocyanin and given an intraperitoneal injection of either (1) a mixture of four fecal bacteria in their nutrient broths, (2) bacteria and broths plus barium sulfate, (3) sterile broths plus barium, (4) sterile barium alone, (5) nutrient broths, or (6) saline. In rats given sterile barium we measured phagocyte delivery to subcutaneous polyvinyl alcohol sponges. We found that (1) the coadministration of barium sulfate was necessary for rats given bacteria to die (P = 0.03) or develop abdominal abscesses (P less than 0.005), (2) suppression of DCH occurred in 70% of rats receiving sterile barium sulfate vs 0% in saline controls (P = 0.0001), (3) early suppression of DCH was associated with subsequent death and abscess formation in rats given bacteria plus barium (P = 0.00002) and with intraabdominal barium collections in rats given barium alone (P less than 0.02), (4) barium sulfate administration caused suppression of phagocyte delivery to subcutaneous sponges: 23.2 X 10(6) cells/site vs 43.1 X 10(6) cells/site in saline controls (P less than 0.005). We conclude that barium sulfate itself has profound systemic effects in the rat model of intraabdominal sepsis. Early suppression of DCH is associated with a poor outcome in septic rats.

Animals↗
PubMed1987

Common pancreaticobiliary channels and their relationship to gallstone size in gallstone pancreatitis.

Bile reflux into the pancreatic duct after impaction of a stone in a common pancreaticobiliary channel has been suggested to be the initiating factor in gallstone pancreatitis. Such reflux would require that the impacted stone be smaller than the length of the common channel. The incidence of common channels was studied and gallstone size was compared with common channel length in patients with gallstone pancreatitis and those with cholelithiasis or choledocholithiasis without pancreatitis. Sixty-seven per cent of patients with gallstone pancreatitis had a common channel present on intraoperative cholangiography versus 32% of patients with cholelithiasis or choledocholithiasis without pancreatitis (p less than 0.005). Common channel length was greater than the diameter of the smallest stone in nine of 27 patients with gallstone pancreatitis and in 13 of 109 patients with cholelithiasis or choledocholithiasis without pancreatitis (p less than 0.025). In conclusion, common channels are more frequent in patients with gallstone pancreatitis than in patients with other biliary tract disease. Furthermore, gallstone pancreatitis is associated with stones that are smaller than the common channel, which favors obstruction of both pancreatic and bile ducts while allowing reflux of contents between them.

Cholangiography↗
PubMed1986

Campylobacter pyloridis is associated with acid-peptic disease in Toronto.

Campylobacter pyloridis has been associated with acid-peptic disease in centres outside Canada. The authors conducted a pilot study to see if this association existed in Toronto. Patients in whom esophagogastroscopy was indicated on clinical grounds were arbitrarily selected for determination of the presence of C. pyloridis. Included in the study were 100 patients who underwent 105 endoscopies. In 75 patients (80 endoscopies) there was some form of acid-peptic disease (inflammation or ulceration of stomach or duodenum). Of those with acid-peptic disease, 34% had C. pyloridis compared with 4% among patients without acid-peptic disease (p less than 0.01). Men with acid-peptic disease were more likely to harbour C. pyloridis than women (48% versus 16%, p less than 0.01). The organisms were curved gram-negative rods that appeared as small colonies after 4 days of incubation under microaerobic conditions. They were strongly urease positive. There was considerable heterogeneity of endoscopic diagnoses. Future clinical studies of C. pyloridis need careful endoscopic and histologic classification.

Adolescent↗
PubMed1985

Pseudomembranous colitis and wound infection following perioperative use of multiple antibiotics.

The prophylactic use of antibiotics in elective surgery of the colon is accepted practice, but it has inherent risks. The authors report the case of a 70-year-old woman who had wound infection and severe, relapsing pseudomembranous colitis due to Clostridium difficile after a short course of antibiotics given orally and parenterally at the time of elective resection of the colon. Perioperatively, she received erythromycin base and neomycin orally, plus netilmicin and metronidazole intravenously. Although the concomitant administration of parenteral antibiotics may enhance the benefit of antibiotics given orally before operation, this does not entirely prevent wound infection. Until the relation between the number of drugs and risk of antibiotic-associated colitis is more clearly defined, caution should be exercised in the use of multiple antibiotics in elective colonic surgery.

Aged↗
PubMed1984

Anergy secondary to sepsis in rats. Relation to outcome.

A rat model was developed to determine if delayed hypersensitivity skin tests during early peritonitis would predict outcome. Presensitized rats were simultaneously tested intradermally with keyhole-limpet hemocyanin and given four types of fecal bacteria and 10% barium sulfate intraperitoneally. Rats were divided into four groups according to inoculum dose. Skin tests were read at 24 hours in survivors and correlated with death and abscesses during the next 19 days. In the two groups with greatest mortality, 35% of anergic rats died, compared with 0% of reactive rats. In the three groups with most abscesses, anergic rats had more abscesses than those that reacted. Overall, 90% of anergic rats died or had abscesses v only 10% of reactors. We concluded that the outcome of untreated peritonitis is determined in the first 24 hours; anergy at that time predicts death or abscess formation.

Abscess↗
PubMed1984

Treatment of intra-abdominal sepsis.

Twenty-three surgeons at three McGill University hospitals were interviewed about their treatment of intra-abdominal sepsis. They described their use of antibiotics, operative practices and other treatment of generalized peritonitis and intra-abdominal abscesses. If more than 75% of respondents used a given method, its use was considered "uniform" unless substantial interhospital variation existed for that method. Treatment was variable in 18 situations. Only four of these involved systemic antibiotic use--drug regimens in appendicitis and intra-abdominal abscess, and duration of antibiotic therapy following appendicitis and perforated duodenal ulcer. The other 14 examples of variation were in operative management. In generalized peritonitis, they were: use of diagnostic paracentesis; abdominal lavage with saline alone versus saline plus antibiotic use; whether the peritoneum should ever be left open; the use or avoidance of drains; primary versus delayed wound closure in appendicitis, bowel perforation and trauma with gastrointestinal perforation and, finally, wound lavage with saline alone or with antibiotics. Treatment of intra-abdominal abscesses varied in regard to the diagnostic and therapeutic roles of percutaneous needle aspiration, the preferred route of drainage of a pelvic abscess, the use of an extra- or trans-serosal approach to a subphrenic abscess, local versus full abdominal exploration for a single abscess and the type of drain used. The authors conclude that operative management of intra-abdominal sepsis varies widely among surgeons. This fact invalidates many "controlled" trials of antibiotics and should focus attention less on drugs and more on surgical treatment.

Abdomen↗