Hospital at night: an organizational design that provides safer care at night

The reduction in the working hours of doctors represents a challenge to the delivery of medical care to acutely sick patients 24 hours a day. Increasing the number of doctors to support multiple specialty rosters is not the solution for economic or organizational reasons. This paper outlines an alternative, economically viable multidisciplinary solution that has been shown to improve patient outcomes and provides organizational consistency. The change requires strong clinical leadership, with organizational commitment to both cultural and structural change. Careful attention to ensuring the teams possess the appropriate competencies, implementing a reliable process to identify the sickest patients and escalate their care, and structuring rotas efficiently are essential features of success.     

Conchotome and needle percutaneous biopsy of skeletal muscle.

Percutaneous muscle biopsy is an important and acceptable technique in the study of conditions involving human skeletal muscle. A review of 436 conchotome and needle muscle biopsies obtained over 18 months in this centre is presented.     

Radiation doses to children during modified barium swallow studies

Background There are minimal data on radiation doses to infants and children undergoing a modified barium swallow (MBS) study. Objective To document screening times, dose area product (DAP) and effective doses to children undergoing MBS and to determine factors associated with increased screening times and effective dose. Materials and methods Fluoroscopic data (screening time, DAP, kVp) for 90 consecutive MBS studies using pulse fluoroscopy were prospectively recorded; effective dose was calculated and data were analyzed for effects of behavior, number of swallow presentations, swallowing dysfunction and medical problems. Results Mean effective dose for the entire group was 0.0826 ± 0.0544 mSv, screening time 2.48 ± 0.81 min, and DAP 28.79 ± 41.72 cGy cm². Significant differences were found across three age groups (≤1.0, >1.0–3.0 and >3.0 years) for effective dose (mean 0.1188, 0.0651 and 0.0529 mSv, respectively; P  <  0.001), but not for screening time or DAP. Effective dose was correlated with screening time (P = 0.007), DAP (P < 0.001), number of swallow presentations (P = 0.007), lower age (P = 0.017), female gender (P = 0.004), and height (P < 0.001). Screening time was correlated with total number of swallow presentations (P < 0.001) and DAP (P < 0.001). Conclusion Screening times, DAP, effective dose, and child and procedural factors associated with higher effective doses are presented for children undergoing MBS studies. This work was supported by the Royal Children’s Hospital Foundation, Brisbane.     

Assessing Human Immunodeficiency Virus Type 1 Tropism: Comparison of Assays Using Replication-Competent Virus versus Plasma-Derived Pseudotyped Virions

Detection of CXCR4-using human immunodeficiency virus by the Trofile assay was compared to that by assays using virus isolates or replication-competent recombinants. Concordance with the Trofile assay was good, but assays using replicating viruses did not increase substantially the ability to detect the presence of CXCR4-using virus.Human immunodeficiency virus type 1 (HIV-1) can be assigned to one of three classes based on its ability to utilize the CCR5 and CXCR4 coreceptors: viruses that use CCR5 but not CXCR4 (R5 virus), those that use CXCR4 but not CCR5 (X4 virus), and those that can use either coreceptor (dualtropic virus). HIV-1 also can be classified according to its ability to replicate and induce syncytia in MT-2 cells (8, 12). The use of CXCR4 is a defining feature of syncytium-inducing (SI) viruses in MT-2 cells; most but not all non-SI (NSI) viruses are R5 (1, 13, 16).Testing to determine coreceptor usage of HIV-1 isolates is essential to identify patients who are suitable candidates for treatment with CCR5 antagonists. The tropism assay (Trofile; Monogram BioSciences, South San Francisco, CA) used in clinical trials of CCR5 antagonists to date is a validated single-cycle assay performed in a Clinical Laboratory Improvement Amendments/College of American Pathologists-certified laboratory; the assay is based on pseudotyped virus and sensitively detects the presence of CXCR4-using virus (14). However, up to 10% of subjects identified as having exclusively R5 virus at screening had evidence of dualtropic or mixed-tropic (D/M) virus at the time treatment with maraviroc or vicriviroc (VCV) was begun (3, 4). To test the hypothesis that the sensitivity of tropism testing could be improved by use of replicating viruses instead of pseudotyped viruses, we compared the results of tropism testing with the Trofile assay to those of assays using replication-competent viruses using clinical samples from AIDS Clinical Trials Group (ACTG) protocol A5211, a phase 2b trial of the investigational CCR5 antagonist VCV (SCH-D; SCH417690; Schering-Plough, Kenilworth, NJ) (4).(This work was presented in part at the 14th Conference on Retroviruses and Opportunistic Infections, Los Angeles, CA, 25-28 February 2007 [5a].)     

Diversity of domain V of 23S rRNA gene sequence in different Enterococcus species

The highly conserved central loop of domain V of 23S RNA (nucleotides 2042 to 2628; Escherichia coli numbering) is implicated in peptidyltransferase activity and represents one of the target sites for macrolide, lincosamide, and streptogramin B antibiotics. DNA encoding domain V (590 bp) of several species of Enterococcus was amplified by PCR. Twenty enterococcal isolates were tested, including Enterococcus faecium (six isolates), Enterococcus faecalis, Enterococcus avium, Enterococcus durans, Enterococcus gallinarum, Enterococcus casseliflavus (two isolates of each), and Enterococcus raffinosus, Enterococcus mundtii, Enterococcus malodoratus, and Enterococcus hirae (one isolate of each). For all isolates, species identification by biochemical testing was corroborated by 16S rRNA gene sequencing. The sequence of domain V of the 23S rRNA gene from E. faecium and E. faecalis differed from those of all other enterococci. The domain V sequences of E. durans and E. hirae were identical. This was also true for E. gallinarum and E. casseliflavus. E. avium differed from E. casseliflavus by 23 bases, from E. durans by 16 bases, and from E. malodoratus by 2 bases. E. avium differed from E. raffinosus by one base. Despite the fact that domain V is considered to be highly conserved, substantial differences were identified between several enterococcal species.     

Clinical relevance of retrograde inferior vena cava or hepatic vein opacification during contrast-enhanced CT

OBJECTIVE: The purpose of this investigation was to explore the clinical relevance of retrograde inferior vena cava or hepatic vein opacification during contrast-enhanced CT. MATERIALS AND METHODS: We retrospectively identified 127 patients who underwent contemporaneous contrast-enhanced CT of the chest or abdomen and echocardiography. On CT, the presence of retrograde inferior vena cava or hepatic vein opacification and the rate of IV contrast injection (> 3 mL/sec, high; < or = 3 mL/sec, low) were recorded. On echocardiography, the presence of tricuspid regurgitation, pulmonary hypertension, or right ventricular systolic dysfunction was recorded. RESULTS: Retrograde inferior vena cava or hepatic vein opacification was more common in studies performed with a high rather than a low contrast injection rate (28/56 vs 6/71 patients, respectively; p < 0.01). This finding was 31% sensitive (5/16) and 98% specific (54/55) for right-sided heart disease at low contrast injection rates, and 81% sensitive (17/21) and 69% specific (24/35) at high injection rates. Multivariate logistic regression models showed that high injection rate, tricuspid regurgitation, pulmonary hypertension, and right ventricular systolic dysfunction were independent predictors of retrograde inferior vena cava or hepatic vein opacification (p < 0.05 for each). CONCLUSION: Retrograde opacification of the inferior vena cava or hepatic veins on CT is a specific but insensitive sign of right-sided heart disease at low contrast injection rates, but the usefulness of this classic sign decreases with high injection rates. This realization is important because many centers increasingly use high-injection-rate CT.     

Atypical cases of gallstone ileus evaluated with multidetector computed tomography

OBJECTIVE: To describe the multidetector computed tomography (CT) findings in 3 patients with atypical gallstone ileus. METHODS: We retrospectively evaluated computed radiography and CT images from three cases of surgically proven gallstone ileus. Two radiologists evaluated by consensus all images for the presence of ectopic gallstone, small bowel obstruction, intrahepatic pneumobilia, cholecystic pneumobilia. One author recorded whether diagnosis of gallstone ileus was made prospectively on radiologic reports and correlated findings to pathology. RESULTS: All cases of gallstone ileus were atypical in that one patient had porcelain gallbladder, one had recurrent pyogenic cholangitis, and one was only 35 years of age. Prospective clinical diagnosis of gallstone ileus was made in only 1 patient at computed radiography and all 3 patients at CT. Retrospectively, small bowel obstruction and cholecystic pneumobilia were identified retrospectively in all 3 patients at both computed radiography and MDCT, and an ectopic gallstone, intrahepatic pneumobilia, and choledochoduodenal fistula was seen in 2, 1, and 0 patients at computed radiography and 3, 2, and 3 patients at CT respectively. CONCLUSION: Multidetector CT is an accurate means to diagnose gallstone ileus, even in patients with atypical features. In particular, multidetector CT is useful for identifying the ectopic gallstone at the transition point between dilated and decompressed bowel.