Value of sonography in obstructive jaundice. Limitations of bile duct caliber as an index of obstruction

Development and validation of a sample entropy-based method to identify complex patient-ventilator interactions during mechanical ventilation

Patient-ventilator asynchronies can be detected by close monitoring of ventilator screens by clinicians or through automated algorithms. However, detecting complex patient-ventilator interactions (CP-VI), consisting of changes in the respiratory rate and/or clusters of asynchronies, is a challenge. Sample Entropy (SE) of airway flow (SE-Flow) and airway pressure (SE-Paw) waveforms obtained from 27 critically ill patients was used to develop and validate an automated algorithm for detecting CP-VI. The algorithm's performance was compared versus the gold standard (the ventilator's waveform recordings for CP-VI were scored visually by three experts; Fleiss' kappa = 0.90 (0.87-0.93)). A repeated holdout cross-validation procedure using the Matthews correlation coefficient (MCC) as a measure of effectiveness was used for optimization of different combinations of SE settings (embedding dimension, m, and tolerance value, r), derived SE features (mean and maximum values), and the thresholds of change (Th) from patient's own baseline SE value. The most accurate results were obtained using the maximum values of SE-Flow (m = 2, r = 0.2, Th = 25%) and SE-Paw (m = 4, r = 0.2, Th = 30%) which report MCCs of 0.85 (0.78-0.86) and 0.78 (0.78-0.85), and accuracies of 0.93 (0.89-0.93) and 0.89 (0.89-0.93), respectively. This approach promises an improvement in the accurate detection of CP-VI, and future study of their clinical implications.

Ultrasonography in gastroenterology

Ultrasonography (US) is a safe and available real-time, high-resolution imaging method, which during the last decades has been increasingly integrated as a clinical tool in gastroenterology. New US applications have emerged with enforced data software and new technical solutions, including strain evaluation, three-dimensional imaging and use of ultrasound contrast agents. Specific gastroenterologic applications have been developed by combining US with other diagnostic or therapeutic methods, such as endoscopy, manometry, puncture needles, diathermy and stents. US provides detailed structural information about visceral organs without hazard to the patients and can play an important clinical role by reducing the need for invasive procedures. This paper presents different aspects of US in gastroenterology, with a special emphasis on the contribution from Nordic scientists in developing clinical applications.

Ultrasound versus liver function tests for diagnosis of common bile duct stones

BACKGROUND

Ultrasound and liver function tests (serum bilirubin and serum alkaline phosphatase) are used as screening tests for the diagnosis of common bile duct stones in people suspected of having common bile duct stones. There has been no systematic review of the diagnostic accuracy of ultrasound and liver function tests.

OBJECTIVES

To determine and compare the accuracy of ultrasound versus liver function tests for the diagnosis of common bile duct stones.

SEARCH METHODS

We searched MEDLINE, EMBASE, Science Citation Index Expanded, BIOSIS, and Clinicaltrials.gov to September 2012. We searched the references of included studies to identify further studies and systematic reviews identified from various databases (Database of Abstracts of Reviews of Effects, Health Technology Assessment, Medion, and ARIF (Aggressive Research Intelligence Facility)). We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We included studies that provided the number of true positives, false positives, false negatives, and true negatives for ultrasound, serum bilirubin, or serum alkaline phosphatase. We only accepted studies that confirmed the presence of common bile duct stones by extraction of the stones (irrespective of whether this was done by surgical or endoscopic methods) for a positive test result, and absence of common bile duct stones by surgical or endoscopic negative exploration of the common bile duct, or symptom-free follow-up for at least six months for a negative test result as the reference standard in people suspected of having common bile duct stones. We included participants with or without prior diagnosis of cholelithiasis; with or without symptoms and complications of common bile duct stones, with or without prior treatment for common bile duct stones; and before or after cholecystectomy. At least two authors screened abstracts and selected studies for inclusion independently.

DATA COLLECTION AND ANALYSIS

Two authors independently collected data from each study. Where meta-analysis was possible, we used the bivariate model to summarise sensitivity and specificity.

MAIN RESULTS

Five studies including 523 participants reported the diagnostic accuracy of ultrasound. One studies (262 participants) compared the accuracy of ultrasound, serum bilirubin and serum alkaline phosphatase in the same participants. All the studies included people with symptoms. One study included only participants without previous cholecystectomy but this information was not available from the remaining studies. All the studies were of poor methodological quality. The sensitivities for ultrasound ranged from 0.32 to 1.00, and the specificities ranged from 0.77 to 0.97. The summary sensitivity was 0.73 (95% CI 0.44 to 0.90) and the specificity was 0.91 (95% CI 0.84 to 0.95). At the median pre-test probability of common bile duct stones of 0.408, the post-test probability (95% CI) associated with positive ultrasound tests was 0.85 (95% CI 0.75 to 0.91), and negative ultrasound tests was 0.17 (95% CI 0.08 to 0.33).The single study of liver function tests reported diagnostic accuracy at two cut-offs for bilirubin (greater than 22.23 μmol/L and greater than twice the normal limit) and two cut-offs for alkaline phosphatase (greater than 125 IU/L and greater than twice the normal limit). This study also assessed ultrasound and reported higher sensitivities for bilirubin and alkaline phosphatase at both cut-offs but the specificities of the markers were higher at only the greater than twice the normal limit cut-off. The sensitivity for ultrasound was 0.32 (95% CI 0.15 to 0.54), bilirubin (cut-off greater than 22.23 μmol/L) was 0.84 (95% CI 0.64 to 0.95), and alkaline phosphatase (cut-off greater than 125 IU/L) was 0.92 (95% CI 0.74 to 0.99). The specificity for ultrasound was 0.95 (95% CI 0.91 to 0.97), bilirubin (cut-off greater than 22.23 μmol/L) was 0.91 (95% CI 0.86 to 0.94), and alkaline phosphatase (cut-off greater than 125 IU/L) was 0.79 (95% CI 0.74 to 0.84). No study reported the diagnostic accuracy of a combination of bilirubin and alkaline phosphatase, or combinations with ultrasound.

AUTHORS' CONCLUSIONS

Many people may have common bile duct stones in spite of having a negative ultrasound or liver function test. Such people may have to be re-tested with other modalities if the clinical suspicion of common bile duct stones is very high because of their symptoms. False-positive results are also possible and further non-invasive testing is recommended to confirm common bile duct stones to avoid the risks of invasive testing.It should be noted that these results were based on few studies of poor methodological quality and the results for ultrasound varied considerably between studies. Therefore, the results should be interpreted with caution. Further studies of high methodological quality are necessary to determine the diagnostic accuracy of ultrasound and liver function tests.

Results of treatment of patients with gallstone disease and ductal calculi by single-stage laparoscopic cholecystectomy and bile duct exploration

INTRODUCTION

Choledocholithiasis is the most common cause of obstructive jaundice. Common bile duct stones are observed in 10-14% of patients diagnosed with gall bladder stones. In the case of gall bladder and common bile duct stones the procedure involves not only performing cholecystectomy but also removing the stones from bile ducts.

AIM

To compare the results of the treatment of patients with gallstone disease and ductal calculi by one-stage laparoscopic cholecystectomy and common bile duct exploration with two other methods: one-stage open cholecystectomy and common bile duct exploration, and a two-stage procedure involving endoscopic retrograde cholangiopancreatography (ERCP) followed by laparoscopic cholecystectomy.

MATERIAL AND METHODS

Between 2004 and 2011 three groups of 100 patients were treated for obstructive jaundice caused by choledocholithiasis. The first group of 42 patients underwent ERCP followed by laparoscopic cholecystectomy. The second group of 23 patients underwent open cholecystectomy and common bile duct exploration, whereas the third group of 35 patients underwent laparoscopic cholecystectomy with common bile duct exploration. The data were analysed prospectively. The methods were compared according to complete execution, bile duct clearance and complication rate. Complications were analysed according to Clavien's Classification of Surgical Complications. The results were compared using the ANOVA statistical test and Student's t-test in Statistica. Value of p was calculated statistically. A p-value less than 0.05 (p < 0.05) signified that groups differed statistically, whereas a p-value more than 0.05 (p > 0.05) suggested no statistically significant differences between the groups.

RESULTS

The procedure could not be performed in 11.9% of patients in the first group and in 14.3% of patients in the third group. Residual stones were found in 13.5% of the patients in the first group, in 4.3% of the patients in the second group and in 6.7% of the patients in the third group. According to Clavien's classification of complications grade II and III, we can assign the range in the first group at 21.6% for grade II and 0% for grade III, in the second group at 21.4% and 3.6% and in the third group at 6.7% and 3.3% respectively.

CONCLUSIONS

The use of all three methods of treatment gives similar results. One-stage laparoscopic cholecystectomy with common bile duct exploration is after all the least invasive, safer and more effective procedure.

Pre-ERCP imaging of the bile duct and gallbladder

Advances in biliary imaging have improved making accurate diagnoses of the presence and causes of biliary obstruction. Abdominal ultrasound is a useful screening tool because it is highly specific for choledocholithiasis. New developments in CT and MRI have also been useful in the diagnosis of biliary disease. Although diagnosis of biliary disease can be achieved in a noninvasive manner, there are limitations to modern MRI and CT cholangiographic techniques; their use may not be necessary or cost effective. MRI and CT imaging of the biliary tract provides opportunities for less-invasive diagnostic techniques but should be used judiciously before interventional endoscopy.

Advances in the investigation of obstructive jaundice

The causes of obstructive jaundice are varied, and timely, accurate methods of investigation are essential to avoid the development of complications. Imaging, invasive or non-invasive, should be carefully selected depending on the suspected underlying pathology in order to determine the degree and level of obstruction along with tissue acquisition and staging where relevant. Several imaging techniques will also allow subsequent therapeutic interventions to be carried out. This article reviews advances in the investigation of obstructive jaundice, highlighting recent developments, many of which at present remain restricted to large centres of expertise, but are likely to become more widespread in use as research progresses and local experience continues to improve.

Diagnostic accuracy of endoscopic ultrasonography in patients with inconclusive magnetic resonance imaging diagnosis of biliopancreatic abnormalities

AIM

To determine the sensitivity and specificity of endoscopic ultrasonography (EUS) in patients with inconclusive magnetic resonance imaging/magnetic resonance cholangiopancreatography (MRI/MRCP) in pancreatobiliary abnormalities.

METHODS

During 10 months, patients with pancreatobiliary diseases referred to endoscopic retrograde cholangiopancreatography (ERCP) because of inconclusive MRI/MRCP diagnosis were scheduled to undergo endoscopic ultrasonography. Patients were divided into four major groups: patients with (i) resectable periampullary neoplasms who were referred to a surgeon, (ii) unresectable periampullary cancer who underwent ERCP for biliary stenting, (iii) bile duct stone who were referred to ERCP for stone extraction, and (iv) normal pancreatobiliary tract. Reference standards for comparison were ERCP, surgery, a biopsy confirming malignancy, or the clinical course during follow up (at least 12 months) in cases without evidences of malignancy.

RESULTS

One hundred and seven patients (51 men; mean [SD] age 60.0 [15.5]) were included in the study. Final diagnoses were common bile duct (CBD) stone (n = 24), periampullary neoplasms (n = 46), others (n = 23) and no pathologic findings (n = 14). EUS determined the staging for clinical decision-making in 47 patients with neoplasms which showed that tumors in 34 patients (79.1%) were unresectable (advanced stage). After EUS, 47 patients (43.9%) did not require ERCP. The accuracy of EUS for the diagnosis of CBD stone and periampullary neoplasms were 96.3% and 99.1%, respectively.

CONCLUSIONS

EUS is a useful modality in cases of inconclusive MRI/MRCP indicating pancreatobiliary disorders.

Long-term follow-up of common bile duct diameter after endoscopic sphincterotomy in patients with common bile duct stones

BACKGROUND AND AIMS

To determine the time to normalization of common bile duct (CBD) diameter after endoscopic sphincterotomy and stone extraction in patients with choledocholithiasis.

METHODS

Patients with CBD dilation due to choledocholithiasis were enrolled. CBD diameter was measured by transabdominal ultrasonography before, and repeated after one, three, six and twelve months after endoscopic sphincterotomy and stone extraction, until normalization of CBD diameter.

RESULTS

Of 115 cases enrolled over a 36-month period, CBD diameter reversed to normal in 71 (61.7%) patients after one month. Of the remaining 44 patients, CBD diameter reversed to normal in 36 patients (including 3 in whom repeat ERCP revealed choledocholithiasis) at the end of three months. CBD diameter had not reversed to normal diameter in 8 (18.2%) patients; none of these patients had symptoms. Two of them had asymptomatic dilated CBD after 6 months with no abnormal liver function tests (LFT); the duct reversed to normal at the last follow-up (month 12).

CONCLUSIONS

Asymptomatic CBD dilation may persist in a minority of patients (18% at the end of 3 months) after removal of CBD stones. A dilated CBD can be attributed to retained choledocholithiasis within the first month, if it is associated with symptoms and abnormal LFT.

The hospitalized patient with abnormal liver function tests

Evaluation of abnormal liver function tests (LFTs) in the hospitalized patient is typically more urgent than the outpatient setting. This process is best organized into four steps. The first step is to determine whether the abnormal LFTs are associated with the illness resulting in the admission to the hospital or preceded the present illness. The second is to determine the etiology of the underlying liver disease. The third step is to evaluate the severity of the liver dysfunction and determine if acute liver failure (ALF) or acute decompensation of chronic liver failure is present. The final step is to look for the presence of associated complications-either those of ALF or chronic liver failure as appropriate.

Endoscopic ultrasonograpy for choledocholithiasis and biliary malignancy

Endoscopic ultrasound (EUS) is a valuable tool in gastrointestinal endoscopy, with various applications such as diagnosis, staging, and evaluation of the pancreaticobiliary system. EUS has comparable sensitivity to magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography (ERCP) for detection of choledocholithiasis. EUS may be considered for evaluation for choledocholithiasis as prelude to ERCP when there is a low to intermediate suspicion for common bile duct stones or when there is an increased risk for complications from ERCP. Endosonography may also be useful in the evaluation of cholangiocarcinoma. Intraductal ultrasound within the bile duct may help differentiate malignant from benign strictures. EUS-guided fine needle aspiration can be helpful in the diagnosis of cholangiocarcinoma, especially in the region of the hilum.

Ultrasound examination in jaundiced patients. Is computer-assisted preclassification helpful?

In this study we attempted to determine the diagnostic accuracy and reproducibility of ultrasonography (US) for jaundice and to see how US can best be combined with preliminary clinical-biochemical diagnoses to plan the invasive work-up. US proved reproducible in two diagnostic departments (127 agreements in 135 cases). But, since obstruction was underdiagnosed (15 double-false negatives), the predictive value of a negative result was only 0.83. By adding a term which represents the US conclusion, obstruction or not, to the Copenhagen pocket diagnostic chart score (based on the logistic model) we found that an obstructive conclusion increases the odds of obstruction by a factor of 25, and a non-obstructive conclusion decreases the odds by a factor of only 1.9. We conclude that the preliminary diagnosis is frequently sufficiently certain to be unalterable by US. This leaves only 40% of the jaundice cases in which US is necessary to plan invasive work-up. The US workload can even, it appears, be reduced to about 22% without appreciable penalty in terms of unrewarding invasive procedures. Using these strict indications, four US examinations seem to suffice to avoid one such error. Relying on either US or clinical-biochemical data alone is inferior to the combined strategy.