Thermal feature-size enhancement in multiphoton photoresists

We demonstrate a new approach for decreasing the feature size in multiphoton absorption polymerization (MAP). Acrylic photoresists containing the photoinitiator KL68 (bis-[4-(diphenylamino) stryl]-1-(2-ethylhexyloxy), 4-(methoxy)benzene) exhibit a proportional velocity (PROVE) dependence, yielding smaller feature sizes at lower fabrication speeds. The feature size in this photoresist decreases substantially with a temperature increase of less than 10°C when all other fabrication parameters are kept constant, suggesting that the PROVE behavior results from local heating. Although higher temperatures have previously been associated with decreased feature sizes in MAP, the effect observed here is considerably stronger than in previous work, and is shown to be a property of the photoinitiator. This discovery opens the door to exploiting thermal gradients to improve resolution in MAP lithography.

Real-time and high-throughput Raman signal extraction and processing in CARS hyperspectral imaging

We present a new collection of processing techniques, collectively "factorized Kramers-Kronig and error correction" (fKK-EC), for (a) Raman signal extraction, (b) denoising, and (c) phase- and scale-error correction in coherent anti-Stokes Raman scattering (CARS) hyperspectral imaging and spectroscopy. These new methods are orders-of-magnitude faster than conventional methods and are capable of real-time performance, owing to the unique core concept: performing all processing on a small basis vector set and using matrix/vector multiplication afterwards for direct and fast transformation of the entire dataset. Experimentally, we demonstrate that a 703026 spectra image of chicken cartilage can be processed in 70 s (≈ 0.1 ms / spectrum), which is ≈ 70 times faster than with the conventional workflow (≈7.0 ms / spectrum). Additionally, we discuss how this method may be used for machine learning (ML) by re-using the transformed basis vector sets with new data. Using this ML paradigm, the same tissue image was processed (post-training) in ≈ 33 s, which is a speed-up of ≈ 150 times when compared with the conventional workflow.

The polarizability response of a glass-forming liquid reveals intrabasin motion and interbasin transitions on a potential energy landscape

Potential energy landscape (PEL) concepts have been useful in conceptualizing the effects of intermolecular interactions on dynamic and thermodynamic properties of liquids and glasses. "Basins", or regions of reduced potential energy associated with locally preferred molecular packing are important PEL features. The molecular configurations at the bottom of these basins are referred to as inherent structures (ISs). Experimental methods for directly characterizing PEL features such as these are rare, largely relegating PEL concepts to theory and simulation studies, and impeding their exploration in real systems. Recently, we showed that quasielastic neutron scattering (QENS) data from propylene carbonate (PC) exhibit signatures of picosecond timescale motion that are consistent with intrabasin motion and interbasin transitions [Cicerone et al., J. Chem. Phys., 2017, 146, 054502]. Here we present optically-heterodyne-detected optical Kerr effect (OHD-OKE) spectroscopy studies on PC. The data exhibit signatures of motion within and transitions between basins that agree quantitatively with and extend the QENS results. We show that the librational component of the OKE response corresponds to intrabasin dynamics, and the enigmatic intermediate OKE response corresponds to interbasin transition events. The OKE data extend the measurement range of these parameters and reveal their utility in characterizing PEL features of real systems.

Empirical Analysis of Optical Kerr Effect Spectra: A Case for Constraint

Ultrafast optical Kerr effect (OKE) spectroscopy is a widely used method for studying the depolarized, Raman-active intermolecular dynamics of liquids. Through appropriate manipulation of OKE data, it is possible to determine the reduced spectral density (RSD), which is the Bose-Einstein-corrected, low-frequency Raman spectrum with the contribution of diffusive reorientation removed. OKE RSDs for van der Waals liquids can often be fit well to an empirical function that is the sum of a Bucaro-Litovitz function and an antisymmetrized Gaussian (AG). Although these functions are not directly representative of specific intermolecular dynamics, the AG fit parameters can provide useful insights into the microscopic properties of liquids. Here we show that fits using the AG function are typically not well-determined, and that equally good results can be obtained with a wide range of fitting parameters. We propose the use of a physically motivated constraint on the amplitude of the AG function, and demonstrate that this constraint leads to more intuitive trends in the fit parameters for temperature-dependent RSDs in 1,3,5-trifluorobenzene and hexafluorobenzene.

How clean is the solvent you use to clean your optics? A vibrational sum-frequency-generation study

Solvents for cleaning optics often come into contact with plastic and/or rubber during storage and transfer. To explore the effects that exposure to these materials can have on solvents, we used vibrational sum-frequency-generation spectroscopy to study a silica optic following cleaning with solvents that had come into contact with either low-density polyethylene, high-density polyethylene, or rubber. Our studies show that even brief contact of acetone, methanol, or isopropanol with plastic or rubber can cause otherwise pure solvents to leave a persistent residue.

Erysipelothrix rhusiopathiae isolates recovered from fish, a harbour seal (Phoca vitulina) and the marine environment are capable of inducing characteristic cutaneous lesions in pigs

In order to determine the diversity and pathogenicity of Erysipelothrix spp. isolates recovered from marine fish, a harbour seal (Phoca vitulina) and the marine environment, 14 isolates were characterized by genotyping, serotyping, determination of the surface protective antigen (spa) gene type and assessment of virulence in a pig bioassay. All 14 isolates were Erysipelothrix rhusiopathiae. Isolates were determined to be of serotypes 2 (n = 3), 3 (n = 1), 4 (n = 1), 12 (n = 1), 15 (n = 1) or 21 (n = 6), and one isolate cross-reacted with serotypes 5 and 21. The spa gene analysis determined that 64.3% (n = 9) were spaA and 35.7% (n = 5) were spaB1. In pigs, 10/14 isolates induced small plaques to diamond-shaped cutaneous lesions consistent with Erysipelothrix spp. infection. The results of this study indicate that the marine E. rhusiopathiae isolates have greater genetic and antigenic diversity than pig isolates and are capable of inducing classical skin lesions in pigs.

Identification of surface protective antigen (spa) types in Erysipelothrix reference strains and diagnostic samples by spa multiplex real-time and conventional PCR assays

AIM

To develop spa multiplex real-time and conventional PCR assays to detect and differentiate between spaA, spaB and spaC genes within Erysipelothrix spp.

METHODS AND RESULTS

For evaluation of the assays, 28 Erysipelothrix spp. reference strains, 25 tissues from pigs inoculated with reference strains of serotypes 1, 2, 5, 10 or 18, and 15 diagnostic samples were used. SpaA was found to be present in Erysipelothrix rhusiopathiae serotypes 1a, 1b, 2, 5, 9, 12, 15, 16, 17, 23 and N; spaB was detected in E. rhusiopathiae serotypes 4, 6, 8, 11, 19 and 21 and spaC was detected in E. sp. strain 2 serotype 18. Spa-related genes were not detected in E. tonsillarum strains (serotypes 3, 7, 10, 14, 20, 22, 24, 25, 26) or E. sp. strain 1 (serotype 13). With the spa multiplex real-time PCR assay, it was also possible to further differentiate spaB into spaB1 (serotypes 4, 6, 8, 19 and 21) and spaB2 (serotype 11). Overall, spaA was detected in seven experimental tissue samples and six diagnostic tissue samples, and spaC in two experimental tissue samples. The detection limits were determined to be five colony-forming units (CFU) per reaction for the spa multiplex real-time PCR assay and 4000 CFU per reaction for the conventional PCR assay.

CONCLUSIONS

Both spa PCR assays were specific and reproducible in the identification of spa types in Erysipelothrix spp.

SIGNIFICANCE AND IMPACT OF THE STUDY

The described spa PCR assays may be useful tools for investigating spa prevalence among strains isolated from field tissues and to determine the role of the Spa proteins in vaccine protection and pathogenesis.

Rapid detection and differentiation of Erysipelothrix spp. by a novel multiplex real-time PCR assay

AIM

The aim of this study was to develop a multiplex real-time PCR assay for the identification and discrimination of Erysipelothrix rhusiopathiae, tonsillarum and Erysipelothrix sp. strain 2 for direct detection of Erysipelothrix spp. from animal specimens.

METHODS AND RESULTS

A primer set and three species-specific probes with different end labelling were designed from the noncoding region downstream of the 5S rRNA coding region. The sensitivity, specificity and repeatability of the assay were validated by analysing 27 Erysipelothrix spp. reference serotype strains and ten septicemia-associated non-Erysipelothrix spp. bacterial isolates. Cross-reactivity with Erysipelothrix sp. strain 1 was not observed with any of the primer probe combinations. The detection limit was determined to be <10 colony forming units and as low as one genome equivalent per PCR . Further evaluation of the Erysipelothrix spp. multiplex PCR was performed by comparing an enrichment isolation culture method and a conventional differential PCR on 15 samples from pigs experimentally inoculated with Erysipelothrix spp. and 22 samples from pigs with suspected natural infection.

CONCLUSION

The multiplex real-time PCR assay was found to be simple, rapid, reliable, specific and highly sensitive.

SIGNIFICANCE AND IMPACT OF THE STUDY

The developed real-time multiplex PCR assay does not require cumbersome and lengthy cultivation steps prior to DNA extraction, obtained comparable results to enrichment isolation, and will be useful in diagnostic laboratories for rapid detection of Erysipelothrix spp.

Novel rinse assay for the quantification of oral neutrophils and the monitoring of chronic periodontal disease

BACKGROUND AND OBJECTIVES

The aim of this study was to develop a single, rapid, noninvasive oral rinse assay to enable the accurate quantification of oral neutrophils. Products released by neutrophils are partly responsible for the destruction observed in periodontitis. Quantification of oral neutrophil levels is important for understanding their role in periodontal diseases. Previous studies have relied on time-consuming serial rinses and cumbersome counting techniques for the collection and quantification of oral neutrophils.

MATERIAL AND METHODS

Patients with chronic periodontal disease provided rinse samples before and after phase I periodontal treatment. Cells in the rinse samples were stained with acridine orange, and neutrophil counts were carried out using a fluorescence microscope and a hemocytometer.

RESULTS

This assay allowed us to detect a significant difference in pretreatment oral neutrophil counts between periodontal disease and healthy control groups (p < 0.001). Patients who responded favorably to phase I therapy demonstrated a 43% reduction in oral neutrophil counts compared with their pretreatment levels (p = 0.019). Patients who did not respond to phase I periodontal treatment showed no significant difference in oral neutrophil levels (p = 0.39).

CONCLUSION

Oral neutrophil levels, as determined by a rapid oral rinse, reflect the severity of periodontal disease and treatment response. A single, rapid, oral rinse assay is an effective means of collecting and quantifying oral neutrophil levels and may serve as an excellent research tool for further study of the role of neutrophils in periodontal diseases.

Laparoscopic surgery in older adults

This article provides an overview of the current role of laparoscopic surgery in older patients. A retrospective review and analysis of the recent English-language literature on laparoscopic procedures with special attention devoted to those articles focused on geriatric patients was performed. Laparoscopic surgery has rapidly become the fastest-growing discipline within the surgical arena and new applications for laparoscopy continue to be reported. The primary benefits to patients of these developments are smaller scars, decreased postoperative pain, and more-rapid return to normal activity. As society ages, more older patients will present with pathology amenable to laparoscopic intervention. Several aspects of laparoscopy impose unique physiologic stresses and, as such, may alter surgical risk to the geriatric patient. In addition, older patients often have delayed surgical interventions because of more-conservative medical management or unusual symptomatology, which may further complicate the laparoscopic approach. These limitations may alter the risk-to-benefit ratio of laparoscopic versus open procedures. Despite this lack of elucidation of full-risk profiles, laparoscopic approaches should be considered regardless of a patient's age.

Development of an anti-vitellin ELISA for the assessment of reproduction in the ridgeback shrimp, Sicyonia ingentis

To investigate the reproductive regulation of the ridgeback shrimp, Sicyonia ingentis, vitellin (Vn) synthesis was studied. Using gel filtration chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Vn was found to have a molecular mass of 322 kDa and to be composed of three subunits of 182, 91 and 85 kDa. Purified Vn was used to prepare anti-Vn antiserum, which was used to develop an enzyme-linked immunosorbent assay (ELISA) with a dynamic range of 0.3-300 ng. The ELISA was used to measure hemolymph levels of yolk proteins. The mean hemolymph concentrations in fresh caught animals ranged from 256 (+/-36.6 S.E.M.) to 1073 (+/-87.6 S.E.M.) mg/ml in stage 2 and 4 animals, respectively. The ELISA was also used to determine the effects of steroid hormone injections in adult non-reproductive female shrimp. One milligram injections of progesterone, 17alpha-hydroxyprogesterone or 17beta-estradiol were administered for three consecutive days to individual females. There were no changes in hemolymph vitellogenin levels during the successive 7-day period following the first injection of any steroid.

Hospital volume can serve as a surrogate for surgeon volume for achieving excellent outcomes in colorectal resection

OBJECTIVE

To examine the association of surgeon and hospital case volumes with the short-term outcomes of in-hospital death, total hospital charges, and length of stay for resection of colorectal carcinoma.

METHODS

The study design was a cross-sectional analysis of all adult patients who underwent resection for colorectal cancer using Maryland state discharge data from 1992 to 1996. Cases were divided into three groups based on annual surgeon case volume--low (< or =5), medium (5 to 10), and high (>10)--and hospital volume--low (<40), medium (40 to 70), and high (> or =70). Poisson and multiple linear regression analyses were used to identify differences in outcomes among volume groups while adjusting for variations in type of resections performed, cancer stage, patient comorbidities, urgency of admission, and patient demographic variables.

RESULTS

During the 5-year period, 9739 resections were performed by 812 surgeons at 50 hospitals. The majority of surgeons (81%) and hospitals (58%) were in the low-volume group. The low-volume surgeons operated on 3461 of the 9739 total patients (36%) at an average rate of 1.8 cases per year. Higher surgeon volume was associated with significant improvement in all three outcomes (in-hospital death, length of stay, and cost). Medium-volume surgeons achieved results equivalent to high-volume surgeons when they operated in high- or medium-volume hospitals.

CONCLUSIONS

A skewed distribution of case volumes by surgeon was found in this study of patients who underwent resection for large bowel cancer in Maryland. The majority of these surgeons performed very few operations for colorectal cancer per year, whereas a minority performed >10 cases per year. Medium-volume surgeons achieved excellent outcomes similar to high-volume surgeons when operating in medium-volume or high-volume hospitals, but not in low-volume hospitals. The results of low-volume surgeons improved with increasing hospital volume but never equaled those of the high-volume surgeons.

Utility of magnetic resonance cholangiography in the evaluation of biliary obstruction

BACKGROUND

Evaluation of suspected biliary obstruction has traditionally involved a variety of imaging modalities including ultrasound, CT, and invasive cholangiography. These techniques have limitations because of poor visualization of intraductal stones (ultrasound and CT) and the need for an invasive procedure (ERCP and percutaneous transhepatic cholangiography). Magnetic resonance cholangiography (MRC) is a noninvasive imaging modality that provides good visualization of the hepatobiliary system. The aim of the present study was to determine the utility of MRC in evaluating patients with suspected biliary obstruction.

STUDY DESIGN

One hundred forty-three patients were identified with suspected acute biliary obstruction and underwent MRC. Patient selection was based on clinical criteria including an elevation in serum liver chemistries or evidence of biliary ductal dilatation on conventional imaging. MRC was performed using a half-Fourier acquisition single-shot turbo spin-echo sequence involving single breath-hold rapid image acquisition. A final diagnosis was determined in each patient based on invasive cholangiography, findings at surgery, and clinical course.

RESULTS

Of the 143 patients, 73 had an obstructing biliary lesion. A malignant process was identified in 25 patients with final diagnoses of pancreatic cancer (n = 15), ampullary cancer (n = 4), cholangiocarcinoma (n = 3), and hepatic or nodal metastases (n = 3). MRC correctly identified biliary obstruction in all these patients and accurately identified the level of biliary obstruction in 24 of 25 patients. Based on the MRC images alone, a malignant process was suspected in 21 of the 25 patients. Forty patients were found to have common bile duct stones and eight patients had a benign distal bile duct stricture. MRC correctly identified common bile duct stones in 37 patients with one false-positive exam (sensitivity = 92%; specificity = 99%). MRC also correctly identified distal biliary strictures in eight patients. In the remaining 70 patients, no definite biliary obstruction was identified by MRC, and in all patients the absence of mechanical obstruction was confirmed by invasive cholangiography or overall clinical course.

CONCLUSIONS

This study demonstrates that MRC is able to accurately identify the level and cause of biliary obstruction in both malignant and benign disease. MRC may prove to be an important noninvasive tool in preoperative evaluation of patients with suspected biliary obstruction and identification of patients most likely to benefit from an invasive radiologic or surgical procedure.

The changing face of mesenteric infarction

Intestinal infarction remains a devastating event despite improvements in clinical recognition as well as diagnostic and therapeutic modalities. Recent changes in the etiology of this disease have not been examined. A retrospective review of 121 consecutive patients over a 6-year period was undertaken. Twenty-three patients died without operation, and mortality in the remaining 98 patients was 50 per cent. The only significant predictor of mortality was an elevated serum lactate at the time of diagnosis. Thirty-one patients (26%) developed infarction while hospitalized for another disease process; excluding patients with obstruction as the etiology of infarction caused this number to rise to 39 per cent. Nonocclusive mesenteric infarction was the most common disease process. The increased incidence of nonocclusive mesenteric infarction is likely due to the development of intestinal ischemia in already systemically ill patients. Nearly half of all cases of intestinal infarction due to nonobstructive causes develop in already hospitalized patients. The development of unexplained acidosis in a postoperative or critically ill patient should prompt a search for a reversible cause of mesenteric ischemia. Intestinal infarction may represent another example of the multisystem organ failure syndrome.

Transplantation of single and paired pediatric kidneys into adult recipients

BACKGROUND

The transplantation of kidneys from cadaveric donors < or = 5 years of age into adult recipients is controversial. The large disparity between donor renal mass and recipient body mass is feared to be problematic. Controversy also exists whether to transplant kidneys from these young donors individually or as a pair into a single recipient.

STUDY DESIGN

We retrospectively reviewed our experience from January 1991 to January 1995 with 22 adult renal transplantations using kidneys from cadaveric donors < or = 5 years of age. Ten patients received single allografts. Twelve received organs paired en bloc. Fifty-two adult recipients from cadaveric donors aged 18-55 years served as controls. All patients received cyclosporine-based immunosuppression. Recipient characteristics did not differ significantly between the groups.

RESULTS

Actuarial patient and graft survival rates were similar for the two groups. The incidence of urinary complications was higher in the recipients of pediatric kidneys than in the adult-donor group (18.2% versus 3.8%, respectively, p = not significant). No grafts were lost from urinary complications. Renal function, as determined by the calculated creatinine clearance, was significantly greater in the pediatric group (76.1 +/- 4.0 versus 61.4 +/- 23.2 mL/min, p = 0.035) by 6 months after transplantation. Recipients of paired pediatric kidneys initially had better renal function (63.9 +/- 21.4 mL/min) than those receiving single pediatric kidneys (38.2 +/- 11.6 mL/min) (p = 0.004), but by 6 months, no significant difference existed. At 2 years, renal function in the pediatric-donor group remained significantly better than in the adult-donor group. Hematocrit levels as a measure of erythropoiesis were similar for single pediatric, paired pediatric, and adult-donor recipients.

CONCLUSIONS

Kidneys from cadaveric donors < or = 5 years of age are suitable for transplantation into adults. Pediatric kidneys provide excellent renal function despite an initially tremendous disparity between renal mass and recipient body mass. Rapid true renal growth probably occurs. No appreciable advantage is achieved by using two pediatric kidneys for a single recipient.

Routine pulmonary artery catheterization does not reduce morbidity and mortality of elective vascular surgery: results of a prospective, randomized trial

OBJECTIVE

The authors determined whether the preoperative placement of a pulmonary artery catheter (PAC) with optimization of hemodynamics results in outcome improvement after elective vascular surgery.

SUMMARY BACKGROUND DATA

The PAC commonly is used not only in patients who are critically ill, but also perioperatively in major elective surgery. Few prospective studies exist documenting its usefulness.

METHODS

One hundred four consecutive patients were randomized to have a PAC placed the morning of operation (group I) or to have a PAC placed only if clinically indicated (group II). Group I patients were resuscitated to preestablished endpoints before surgery and kept at these points both intraoperatively and postoperatively. Group II patients received standard care.

RESULTS

There was one death in each group. An intraoperative or postoperative complication developed in 13 patients in group I versus 7 patients in group II (p = not significant). Group I patients received more fluid than did group II patients (5137 +/- 315 mL vs. 3789 +/- 306 mL; p < 0.003). There was no significant difference in either overall or surgical intensive care unit length of stay. Only one patient in group II required a postoperative PAC.

CONCLUSIONS

Routine PAC use in elective vascular surgery increases the volume of fluid given to patients without demonstrable improvement in morbidity or mortality.

Laparoscopic cholecystectomy: applicability in the geriatric population

Elderly patients with cholelithiasis are more likely than nonelderly patients to present with an acute complication of gallstone disease such as acute cholecystitis (AC), gallstone pancreatitis (GSP), or common bile duct stones (CBDS). These acute complications may make laparoscopic cholecystectomy (LC) more hazardous, with a potential increase in perioperative morbidity or need for open conversion. The applicability of LC in the geriatric population is, therefore, unclear. We reviewed 283 consecutive patients undergoing attempted LC. Patients were classified as presenting with complicated (AC, GSP, or CBDS) or uncomplicated gallstone disease. Elderly patients were significantly more likely than younger patients to present with AC (40% versus 18%), GSP (19% versus 6%), and CBDS (21% versus 5%) (all P < 0.05). Elderly patients with chronic, uncomplicated gallstone disease (n = 20) and nonelderly patients with uncomplicated disease (n = 159) had similar open conversion rates (5% and 7%, respectively). In contrast, the open conversion rate in elderly patients with complicated gallstone disease (n = 42) was significantly higher (50%) compared to nonelderly patients with complicated disease (n = 62; rate, 16%; P < 0.05). Perioperative morbidity and length of stay were also significantly increased in the elderly group, primarily due to the high percentage of elderly patients with complicated disease. These results suggest that elderly patients with uncomplicated gallstone disease appear to be excellent candidates for LC, and this should be considered before complicated disease develops. Conversely, early conversion or planned open cholecystectomy may be warranted in the elderly presenting with acute complications of cholelithiasis.

Quality and retrieval of obstetrical anaesthesia randomized controlled trials

PURPOSE

Randomized controlled trials (RCTs) are suitable for meta-analysis and systematic reviews provided they are of high quality and are easy to retrieve. We determined these attributes of RCTs in obstetrical anaesthesia in a sample of available journals that are indexed in MEDLINE.

SOURCE

Randomized controlled trials published between January 1985 and December 1994 in seven anaesthetic and three obstetric journals were identified by a MEDLINE search, and by handsearch of the same journals. Each RCT was assigned a quality score by a blinded rater using a reliable and validated scaled. The quality of each RCT was described and compared over time and by journal. The comparative yield of MEDLINE and hand-search was evaluated.

PRINCIPAL FINDINGS

Three hundred and forty RCTs were retrieved by MEDLINE and handsearch. Two hundred and twenty seven (65%) were identified by the MEDLINE search and 333 by the handsearch (98%). The median quality score was 3/5. There was no difference in score over time. Anesthesiology had the highest median score, Anaesthesia had the lowest (P < 0.05).

CONCLUSIONS

Care must be taken when reviewing obstetrical anaesthesia research. Strategies in addition to a MEDLINE search must be used to identify RCTs since more than one third were missed using MEDLINE alone. Poor quality RCTs are more likely to be biased in favour of a new treatment. Therefore, to increase the validity of reviews sensitivity analyses based on quality should be done.

General surgical care in the nursing home patient: results of a dedicated geriatric surgery consult service

BACKGROUND

Although recent interest has centered on diseases that require operation in the elderly, few data are available about the effects of surgical intervention on the frail nursing home patient.

STUDY DESIGN

A longitudinal study was conducted of the nature of illness requiring operation and intervention in residents of a geriatric center associated with a tertiary care medical center. A unique consult service for the patients was established and all referrals were prospectively followed up.

RESULTS

The actuarial 18-month survival of patients referred was 35 percent. Although maintenance care (e.g., decubitus ulcer, stoma, and enteral tube care) made up a substantial number of referrals (32.5 percent), common surgical diseases of the abdomen, breast, and vascular system were routinely encountered (55 percent). In patients undergoing surgery, the 30-day mortality rate was 8.5 percent, and the complication rate 9.4 percent. Although patients undergoing major abdominal and vascular procedures had a higher complication rate (17.6) percent than those undergoing lesser procedures (6.3 percent, p = 0.05), there was no difference in the 30-day mortality (9.8 compared with 6.3 percent, respectively) or 18-month actuarial survival (33 compared with 32 percent, respectively) rates. The overall actuarial survival was adversely affected by the presence of coronary artery disease (relative risk [RR], 3.27) and dementia (Mini-Mental State Examination score less than 24; RR, 2.39) and age older than 70 years (RR, 2.03). The overall survival was unaffected by the actual need for operation, the magnitude of the procedure performed, gender, the number of comorbid conditions, and the preoperative code (resuscitative) status.

CONCLUSIONS

Although nursing home patients referred for surgical intervention have poor survival rates, the use of surgical procedures does not adversely affect overall survival. This supports the idea that care for this patient population is not futile, and quality of life, patient dignity, and relief of suffering can provide a alternative to curative therapy.

Will stereotactic breast biopsy achieve results as good as current techniques?

Stereotactic procedures recently have been advocated to replace most needle localization and open biopsy procedures. In order to provide a baseline for comparison at our institution, a retrospective review of our results over the last 3 years was performed. During this time period, 496 biopsies were performed in 480 patients. Needle localization was done in 311 cases, whereas the remaining 185 biopsies were done for palpable masses. There were no significant differences in either the positive rate (19.0% vs 13.5%) or the infection rate (2.6% vs 1.6%) in the two groups. Follow-up of all patients has revealed no missed carcinomas and no referrals to a plastic surgeon for a poor cosmetic result. Current breast biopsy techniques yield good results, with acceptably low morbidity rates. Given that approximately one in five needle localization biopsies detects a malignancy, a negative result following a stereotactic biopsy may not preclude a needle localization procedure. It is therefore unlikely that stereotactic procedures will lead to an overall decrease in health care costs. Surgeon involvement will be crucial to assure best and most cost-effective results.

Transplantation of kidneys from expanded criteria donors

BACKGROUND

The critical shortage of organs for transplantation has resulted in a controversial expansion of the criteria used to define a suitable cadaveric organ donor. The shortage of kidneys has a particularly hard impact on those patients on the waiting list who have uncommon major histocompatibility antigens or who are highly immunized.

METHODS

To determine outcomes between patients receiving grafts from expanded criteria donors (ECDs) and others, a retrospective review of 105 consecutive kidney transplantations performed at a single institution during a 3 1/2 year period was conducted. A total of 44 (41.9%) patients received kidneys from ECDs, 45 (42.9%) from conventional cadaveric donors, and 16 (15.2%) from live donors. All patients were treated by the same physicians and received either triple or quadruple sequential immunosuppressive therapy. In general, high risk recipients did not receive kidneys from ECDs.

RESULTS

Actuarial graft survival, incidence of delayed function, length of stay, and hospital charges were not significantly different between the ECD and conventional cadaveric donor groups of recipients. A higher incidence of urinary complications occurred in the ECD group (p=0.03). This incidence was noted primarily in the recipients of kidneys from donors 5 years of age or younger. However, no allografts were lost as a result of urinary complications. ECD kidneys that were imported from outside the local catchment area accounted for approximately 25% of all cadaveric transplantations performed.

CONCLUSIONS

With appropriate selection of organs from ECDs, acceptable results can be obtained. ECD organs can serve to partially alleviate the extreme organ shortage. These organs should be procured and made available to those centers willing to use them.

Outcome following colon surgery in the octagenarian

The results of colon surgery in all individuals aged 80 years or greater at one teaching institution during the 1987-1993 time period were reviewed. Sixty patients, ranging in age from 80 to 92 years, underwent 41 elective operations and 21 emergency procedures. Emergency procedures resulted in death or a major complication in over one-half of patients, and only six were ultimately able to return home. Conversely, elective procedures were relatively well tolerated, and 31 of 37 survivors returned immediately to independent living (P = 0.006). Mortality was 33.3 per cent in emergency cases versus 9.8 per cent in elective operations (P < 0.03). The occurrence of a postoperative complication increased the length of stay by an average of 12 days. These data suggest that elective colon surgery in the elderly produces results little different from the population at large. Conversely, emergency operations are associated with a high morbidity and mortality rate. Age alone should not be a determining factor in who undergoes an elective colon operation. Greater efforts should be made to screen elderly individuals to limit emergency surgery.

Supraventricular tachyarrhythmias in the surgical intensive care unit: an under-recognized event

Over a 1-year period, 28 patients (13.6% of admissions to one surgical intensive care unit) developed the new onset of a supraventricular tachyarrhythmia requiring treatment. None was associated with intravascular catheter placement. There were 16 women and 12 men with an average age of 69.8 years (range 49-92). In nine of the patients, the diagnosis was made coincidental with or immediately before the onset of postoperative sepsis. Twenty-six patients responded to medication and two required cardioversion. Mortality was 28.6 per cent (8/28), but none as a direct result of the arrhythmia. One patient had a myocardial infarction secondary to the arrhythmia. Supraventricular tachyarrhythmias are a relatively common problem in the critically ill surgical patient. Surgeons who care for such individuals need to be familiar with the differential diagnosis and treatment of arrhythmias. The new onset of a supraventricular tachyarrhythmia in an otherwise stable patient should prompt a search for a treatable cause of sepsis.

Immediate laparoscopic cholecystectomy as definitive therapy for acute cholecystitis

The objective of this study was to determine the safety and efficacy of immediate laparoscopic cholecystectomy in the management of acute calculous cholecystitis. A prospective data collection was performed on all patients admitted to one surgical service over a 2-year period. The patients were managed by a uniform protocol consisting of (1) preoperative ERCP when common duct stones were suspected; (2) operation within 24 h of diagnosis; and (3) selective operative cholangiography. Previous surgery was not a contraindication to inclusion. The setting was an urban teaching hospital. There were 52 patients, 34 females and 18 males. Nineteen had undergone previous abdominal surgery. Five patients had preoperative ERCP and five had intraoperative cholangiography. The patients underwent laparoscopic cholecystectomy 0.8 +/- 0.4 days postadmission. Four (7.7%) were converted to open cholecystectomy. Fifty-eight percent had spillage of bile and/or stones. Patients went home 2.3 +/- 1.6 days postoperatively. There were no deaths and two complications: a subhepatic biloma and a superficial wound infection. Follow-up of all patients has revealed no late complications. We conclude: (1) Immediate laparoscopic cholecystectomy is safe and effective for acute cholecystitis even when complicated by previous surgery, inflammatory adhesions, and gangrene. (2) Intraoperative spillage of bile and stones does not lead to an increase in early complications. (3) Cholangiography is needed only when clinically indicated. (4) Laparoscopic cholecystectomy should be the treatment of choice for patients admitted for acute cholecystitis.

Malignancy is the most common cause of gastric outlet obstruction in the era of H2 blockers

OBJECTIVES

To determine the relative incidence of malignant and nonmalignant pathology in patients presenting with gastric outlet obstruction in the era of H2 blockers and to determine whether clinical features can differentiate between the two causes.

METHODS

The charts of 33 consecutive patients with gastric outlet obstruction admitted to one institution between July 1990 and November 1993 were reviewed to determine etiology, management, and outcome. The diagnosis of gastric outlet obstruction was based on clinical presentation, an upper gastrointestinal barium study, and/or an inability during upper endoscopy to intubate the second portion of the duodenum. Patients with gastroparesis or a previously known cancer were excluded.

RESULTS

Sixty-one percent (20 patients) had malignancy as the cause of their gastric outlet obstruction. Thirty-nine percent (13 patients) had benign disease. The patients with cancer tended to be older, and fewer had a history of peptic ulcer disease, although these factors were not statistically significant. The use of nonsteroidal anti-inflammatory drugs was not associated with gastric outlet obstruction. Four patients had malignancy that had not been suspected before operation despite numerous endoscopic and radiological studies.

CONCLUSION

The incidence of malignancy in patients presenting with gastric outlet obstruction is greater than 50%. The etiology of gastric outlet obstruction cannot be predicted by age, history of peptic ulcer disease, or nonsteroidal anti-inflammatory drug use. The endoscopic treatment of gastric outlet obstruction should be approached with caution because malignancy cannot be reliably excluded by endoscopic or radiological studies.

Cholecystectomy in the peritoneal dialysis patient. Unique advantages to the laparoscopic approach

Laparoscopic cholecystectomy has proven to be a safe and effective treatment for symptomatic gallstone disease. Several subsets of patients, however, may not be candidates for the laparoscopic approach, including patients with morbid obesity, acute cholecystitis, and previous abdominal surgery. Because of peritoneal thickening and abdominal adhesions secondary to peritoneal dialysis, the applicability of laparoscopic cholecystectomy in patients maintained on chronic peritoneal dialysis is also unclear. We performed laparoscopic cholecystectomy on three peritoneal dialysis patients without intraoperative complications. We have noted several unique advantages to laparoscopic surgery in this patient population and advocate this approach in peritoneal dialysis patients requiring cholecystectomy.

Acute abdomen in the hemodialysis patient population

BACKGROUND

The cause and frequency of the acute abdomen in patients undergoing hemodialysis are not well reported. Previous studies associate bowel infarction with hemodialysis, but dialysis generally is not implicated as a risk factor for mesenteric ischemia.

METHODS

The records of 567 patients undergoing long-term hemodialysis during the period from July 1988 to June 1993 were retrospectively reviewed.

RESULTS

Twelve patients (2.1% of the hemodialysis population) were admitted with acute abdominal pain or sepsis. They were demographically no different than their counterparts who did not have an acute abdomen. The final diagnoses were bowel infarction in 11 patients and acute pancreatitis in one. Principal areas of involvement were equally divided between large and small intestine and were due to nonocclusive mesenteric ischemia in all cases. Six patients had an occluded hemodialysis fistula on admission, suggesting hypotension and/or hypovolemia as a possible etiologic factor. Overall, mortality and major morbidity rates were 50% and 25%, respectively.

CONCLUSIONS

An acute abdomen is a relatively uncommon problem in the hemodialysis population but is associated with a high mortality. Mesenteric infarction is the most common cause and should be the presumptive diagnosis until proven otherwise.

Pseudocysts and pseudoaneurysms: surgical strategy

Eight patients over an 8-year period required operation for spontaneous hemorrhage as a complication of a pancreatic pseudocyst. Three patients presented with abdominal pain or jaundice and bled in hospital while undergoing work-up. Four patients were admitted with upper gastrointestinal bleeding and one with intraperitoneal bleeding. Five patients were managed by pancreatic resection (two of the head and three of the tail) and three were managed by arterial ligation and internal drainage. There was one death (mortality rate, 12.5%). The first four patients in the series had their operations delayed secondary to a perceived need for further work-up or an inability to make an exact diagnosis of the bleeding site. All rebled, necessitating an emergency operation. The last four patients underwent an expedited workup and operation. Successful treatment of bleeding pancreatic pseudocysts requires good surgical judgment, especially when nonoperative methods fail or aren't applicable. The risk of recurrent hemorrhage is high, suggesting the need for immediate intervention once the diagnosis is made. Resection provides definitive control, although selected patients with easily accessible vessels may be managed more conservatively with ligation and drainage.

Antrectomy. A safe and effective bypass for unresectable pancreatic cancer

BACKGROUND

Pancreatic cancer is most often diagnosed too late for curative resection. Operative therapy, therefore, involves relief of biliary obstruction and relief or prevention of gastric outlet obstruction. Previous studies show that gastrojejunostomy done either therapeutically or prophylactically often causes delayed gastric emptying.

OBJECTIVE

To describe the results of antrectomy with Billroth II reconstruction (A/BII) as the palliative operation for gastric outlet obstruction.

SUBJECTS

Fifty patients with unresectable pancreatic cancer underwent A/BII without vagotomy from 1987 through 1993. Of these patients, 42 underwent simultaneous biliary bypass; six had undergone biliary bypass from 3 weeks to 34 months previously; and two with cancer originating in the uncinate process had no biliary bypass.

RESULTS

One 87-year-old patient died on day 12 of azotemia and pulmonary insufficiency. The other 49 patients were discharged tolerating an oral diet an average of 11.3 days (range, 5 to 29 days) after A/BII. The length of stay following A/BII was not related to the extent of disease or to preoperative weight loss but was increased in older patients.

CONCLUSION

The A/BII is a safe and effective bypass in patients with unresectable pancreatic cancer.

Telerobotic assisted laparoscopic surgery: initial laboratory and clinical experience

OBJECTIVES

To assess the feasibility of telerobotic assisted surgery.

METHODS

In a laboratory model, a cholecystectomy, splenectomy, and nephrectomy were performed by an inexperienced surgeon who was being mentored by an experienced surgeon stationed at a remote site. The remote surgeon controlled the laparoscopic camera by utilizing a telerobotic system. In patients, laparoscopic cholecystectomy, varix ligation, and bladder suspension were performed by an experienced team utilizing a robotic system controlled by an experienced surgeon from a remote site.

RESULTS

In both the laboratory and clinical setting, all procedures were successfully completed without complications.

CONCLUSIONS

Current technology is available to successfully allow for telerobotic assisted surgery.

Bleeding gastroduodenal ulcers: improved outcome from a unified surgical approach

We have adopted a uniform, aggressive approach to the management of upper gastrointestinal hemorrhage. Our protocol consists of admission to a surgical service, endoscopy within 24 hours, and liberal use of intensive care monitoring. Urgent or emergency surgery is recommended for the following criteria: 1) presence of shock upon admission; 2) resuscitation requirements of greater than 4 units of blood; 3) age 65 years or older; 4) ulcer size greater than 2 cm or with stigmata of recent hemorrhage; or 5) history of a previous admission for an ulcer complication. During the period 1986-1990, 66 patients met the criteria for operation. There were 45 males and 21 females with an average age of 53.5 years (range, 29-84). Thirty-seven bled from a gastric ulcer and 29 from a duodenal ulcer. They were transfused an average of 5.0 units of blood (range, 0-13). There were no hospital deaths, but 11 patients (16.7%) had 12 postoperative complications. We conclude that a unified, single team approach to gastroduodenal hemorrhage with expedited work-up and early operation prevents death from this treatable condition.

Total abdominal colectomy: conditions defining outcome

Published conclusions that total abdominal colectomy is a safe procedure need to be qualified by analysis of specific risk groups. We reviewed the records of 87 consecutive patients undergoing total abdominal colectomy at our institution to determine the factors affecting morbidity and mortality. Underlying disease and urgency of operation were the primary determinants of outcome. Mortality was 5.9 per cent in the patient groups who had the procedure done non-emergently or for bleeding when transfusion requirements were less than 10 units. Mortality was 10-fold higher (55.6%) in the groups where the procedure was done either as an emergency for non-hemorrhagic reasons or when perioperative transfusion requirements reached 10 units (P < 0.001). Morbidity followed the same distribution. Death resulted primarily from shock, myocardial infarction, or sepsis from an anastomotic leak. Limiting transfusion needs to less than 10 units, by either more aggressive evaluation or earlier operation, and more liberal use of ileostomy were the only maneuvers identified that may decrease risk in the emergency setting. Elective operation before complications arise will likely result in improvement in morbidity and mortality rates.

Limited role of barium enema examination preceding colostomy closure in trauma patients

Whether trauma patients should undergo barium enema (BE) examination of the colon prior to colostomy closure has recently been questioned. To ascertain the utility of BE and its impact on postoperative course in this patient population, we reviewed 86 trauma patients who underwent colostomy closure during a 12-year period at our institution. There were 82 males and four females with an average age of 28 years. Ninety-five percent of the injuries were the result of penetrating trauma. Sixteen patients had rectal injuries. Fifteen of these had BE greater than 6 weeks post-trauma and all showed healing of the injury. Of the 70 patients with colonic injuries, 43 (group 1) had BE prior to colostomy closure. Ninety-eight percent (n = 42) of these studies were negative. The only positive finding did not affect the planned surgical procedure. Group 2 (n = 27) did not have a BE prior to colostomy closure. Overall complication rates were not significantly different between group 1 (18.6%) and group 2 (29.6%). We conclude that BE prior to colostomy closure for colonic injuries yields little useful information and does not affect the morbidity rate prior to colostomy closure. Its routine usage should be abandoned. The role of barium enema in assessing rectal injury status is less clear because of the small number in our series, but probably offers no advantage over proctoscopy.

The technique of visceral packing: recommended management of difficult fascial closure in trauma patients

Since 1986, we have cared for 17 patients whose abdomen could not be closed because of bowel edema and loss of abdominal wall compliance. These patients were managed by a technique of visceral packing with the intestines kept in place by a combination of rayon cloth, gauze packs, and retention sutures. This packing was changed in the operating room under general anesthesia until the edema was sufficiently resolved to allow for closure. Two patients died within 24 hours of operation from irreversible shock. The remaining 15 patients had their fascia successfully closed with an average of two additional anesthetics. There was one case of fasciitis associated with the development of an intra-abdominal abscess and one patient died of late sepsis. There was no early postoperative ventilatory compromise or acute oliguric renal failure. Other direct complications have been minor with no enterocutaneous fistulae, dehiscence, or incisional hernia. Visceral packing of posttraumatic abdominal wounds circumvents expected complications of intraperitoneal hypertension and enhances the chance for survival. Its ease and low morbidity also lends itself to a wide variety of other uses.

Morbidity and timing of colostomy closure in trauma patients

The reported morbidity of colostomy closure in trauma patients varies from 5 to 27 per cent. Low morbidity rates are cited as a factor favouring colostomy creation and against expanded indications for primary repair in the treatment of colonic injuries. In order to assess the morbidity of colostomy closure, we reviewed all colonic injuries from 1979 to 1991 at our institutions. In all, 86 trauma patients who underwent colostomy creation and closure were identified. There were 82 men and four women with an age range of 16 to 74 years (mean 28.1 years). Of these, 95 per cent (N = 82) resulted from penetrating trauma. Of the patients, 63 per cent (N = 54) received end colostomies and 81 per cent (N = 70) of the patients had associated injuries. Of the patients, 38 per cent (N = 33) had a complication with their initial operation. There were no deaths after colostomy closure, but a total morbidity of 24.4 per cent (N = 21) was noted. There were 11 anastomotic complications (two of which required repeat laparotomy) and nine wound infections. The average length of stay was 10.4 days. Morbidity was concentrated in the group who had complications at their initial hospitalization. This was especially true if these patients underwent closure earlier than 3 months after injury. Conversely, if the first operation was uncomplicated, waiting longer than 3 months to perform colostomy closure did not improve results further.

Improving outcome from extremity shotgun injury

The charts of 124 consecutive patients with extremity shotgun injuries managed over an 8-year period were reviewed to assess the results of a uniform protocol. This consisted of liberal use of arteriography, prompt exploration, wide debridement or fasciotomy, and frequent operating room dressing changes for large wounds. Thirty-three patients had arterial injuries and 16 had major venous injuries. Twenty patients had major soft tissue wounds and there were 15 significant long bone injuries. Results overall were excellent with over 95 per cent of patients retaining an intact and functional limb. Of the six limb amputations, three were done primarily and three were performed for late septic complications. Two of these late amputations were done following inadequate initial revascularization at referring hospitals. Early wound closure, liberal use of arteriography and fasciotomy, early fracture stabilization, and repair of all significant vascular injuries contribute to a successful outcome in patients with extremity shotgun wounds.

Use of the pulmonary artery catheter to reduce operative complications

Despite several prospective, randomized trials that demonstrated reductions in operative morbidity and mortality rates, routine use of invasive monitoring has not achieved widespread acceptance. This probably comes from skepticism about the validity of some of the studies along with known complications of the pulmonary artery catheter. The major studies are reviewed and a rational approach to monitoring is presented.

Surgical issues in the management of the HIV-infected patient

As of 1992, approximately 1,000,000 Americans are infected with HIV. The natural history of the illness includes a relatively long latent period (about 10 years) between infection and development of AIDS. Surgeons are called on to participate in the management of these patients, usually for diagnostic biopsies, supportive measures, or intraabdominal events. Precautions and safe surgical practices will minimize the risk of HIV transmission from patient to surgeon (or surgeon to patient).

The effects of hypothermia and injury severity on blood loss during trauma laparotomy

To assess the relationships between core temperature (T) and other factors relating to operating room (OR) blood loss and mortality following abdominal injury, the records of 122 patients undergoing laparotomy for trauma at Detroit Receiving Hospital over a 1-year period (1989) were reviewed. Most injuries were penetrating (86%) and the mortality rate was 8.2%. Overall, 57 of 122 (47%) had hypothermia (T < or = 35 degrees C) upon arrival in the OR. There was a significant correlation between admission blood pressure and lowest intraoperative temperature (r = 0.60; p < 0.001). Multiple regression analysis revealed that the patient's lowest temperature (p < 0.001) and Trauma Score (TS); p < 0.0015), but not Abdominal Injury Severity Score (AISS) (p = 0.25) correlated with OR blood loss. The 28 patients with high TS (15 or 16) and AISS > or = 9 had significantly less blood loss when the OR temperature was maintained above 35 degrees C versus 33 degrees-35 degrees C (540 +/- 580 mL vs. 1820 +/- 1160 mL; p < 0.003). This suggests that hypothermia may exacerbate OR blood loss independent of degree of physiologic or anatomic injury. Thus hypothermia is common in patients undergoing a laparotomy for trauma. Trauma scores and the presence of shock preoperatively correlate with the development of intraoperative hypothermia. Hypothermic patients with similar injury severity have greater blood loss. Prevention and rapid correction of hypothermia during resuscitation and surgery appear to be extremely important in reducing blood loss in this patient population.

Diagnostic laparoscopy in critically ill intensive-care-unit patients

The diagnosis of intraabdominal sepsis in critically ill intensive-care-unit patients remains a challenge. Diagnostic laparoscopy has been performed in seven such patients following admission for coronary artery bypass surgery, gram-negative sepsis, major burns, pneumonia, myocardial infarction, and post-pneumonectomy. Laparoscopy revealed acalculous cholecystitis in two patients (one removed laparoscopically), gangrenous colon in two, cirrhosis with liver infarction in one, and, in two patients, no pathology. Although five patients died postoperatively, none was related to the laparoscopy. There were no intraoperative complications and no known pathology was missed. Because of its ease and accuracy, diagnostic laparoscopy should be considered in all critically ill patients suspected of harboring intraabdominal pathology. Further studies are needed to fully establish its efficacy and safety.

Pseudoaneurysm of the gastroduodenal artery arising within a pancreatic pseudocyst

A case is presented of a 41-year-old man admitted for obstructive jaundice. Work-up revealed a pseudocyst of the pancreatic head which contained a large pseudoaneurysm of the gastroduodenal artery. After an unsuccessful attempt at embolization, the patient was treated with an uncomplicated pancreaticoduodenectomy.