Can passive leg raising be used to guide fluid administration?

Predicting fluid responsiveness has become a topic of major interest. Measurements of intravascular pressures and volumes often fail to predict the response to fluids, even though very low values are usually associated with a positive response to fluids. Dynamic indices reflecting respiratory-induced variations in stroke volume have been developed; however, these cannot be used in patients with arrhythmia or with spontaneous respiratory movements. The passive leg raising (PLR) test has been suggested to predict fluid responsiveness. PLR induces an abrupt increase in preload due to autotransfusion of blood contained in capacitance veins of the legs, which leads to an increase in cardiac output in preload-dependent patients. This commentary discusses some of the technical issues related to this test.     

Can tap water be used to irrigate wounds in A&E?

After critiquing the seven selected articles, it seems likely that tap water can be used as an irrigant and cleansing agent for soft-tissue wounds. However, the current research on tap water has involved human and rat wound studies and tap water culture studies (Dire, 1990; Riyat and Quinton, 1997; Moscati, 1998). The research is strong, but limitations in current research remain an issue for practice (Towler, 2000). The use of tap water is a cost and practicality issue, and changing current practice is always difficult, as it would seem that the use normal saline is more of a ritualistic process rather than one based on hard evidence (Glover, 1999). Two key conclusions could be drawn from the available research: The tap water tested was generally agreed to be safe from harmful bacteria and had no contaminating bacteria; Human and rat models showed a clear benefit in using tap water to cleanse soft tissue wounds, thus concluding tap water is safe for use on wounds (Towler, 2000). The financial benefits were also stated in the studies; tap water can have huge cost-saving potential for A&E departments. In an increasingly cost-conscious NHS this could be a major driving factor for changing practice. However, there were limitations in the methodologies of the selected articles in this critique. Most of the studies measured wound infection rates, but the various researchers did not take into account other factors affecting the likelihood of infection rates and wound progress which would ultimately affect wound infection rates by killing any bacteria in vivo.     

Can administrative data be used to compare postoperative complication rates across hospitals?

BACKGROUND: Several quality assessment systems use administrative data to identify postoperative complications, with uncertain validity. OBJECTIVES: To determine how accurately postoperative complications are reported in administrative data, whether accuracy varies systematically across hospitals, and whether serious complications are more consistently reported. DESIGN: Retrospective cohort. SUBJECTS: Nine hundred ninety-one randomly sampled adults who underwent elective lumbar diskectomies at 30 nonfederal acute care hospitals in California in 1990 to 1991. Hospitals with especially low or high risk-adjusted complication rates, and patients who experienced complications, were over sampled. MEASURES: Postoperative complications were specified by reviewing medical literature and consulting clinical experts; each complication was mapped to ICD-9-CM. Hospital-reported complications were compared with our independent recoding of the same records. RESULTS: The weighted sensitivity, specificity, and positive and negative predictive values for reported complications were 35%, 98%, 82%, and 84%, respectively. The weighted sensitivity was 30% for serious, 40% for minor, and 10% for questionable complications. It varied from 21% among hospitals with fewer complications than expected to 45% among hospitals with more complications than expected. Only reoperation, bacteremia/sepsis, postoperative infection, and deep vein thrombosis were reported with at least 60% sensitivity. Half of the difference in risk-adjusted complication rates between low and high outlier hospitals was attributable to reporting variation. CONCLUSIONS: ICD-9-CM complications were underreported among diskectomy patients, especially at hospitals with low risk-adjusted complication rates. The validity of using coded complications to compare provider performance is questionable, even with careful efforts to identify serious events, although these results must be confirmed using more recent data.     

Can the Internet be used as a medium to evaluate knee angle?

Telemedicine promises to revolutionize medical care delivery in rural and remote areas. The ability to accurately evaluate physical impairment via the Internet is important to the possible future provision of Internet-based physiotherapy. This study evaluated the reliability and validity of assessing knee range of motion via the Internet. Two therapists evaluated knee angle on a single subject via two methods of assessment: the Internet and the traditional method (face-to-face). Nine random positions of the knee were chosen with the principal examiner performing 20 face-to-face and two sets of 20 Internet measures in each position (n=540). The secondary therapist performed Internet assessments only. The Internet connection was established at a readily available speed of 17 kbit/s. The Internet-based goniometer was found to be a valid tool for measuring both knee flexion and extension angles. It was shown to possess both high intra and inter-rater reliability. Difference average plots of the scores verified the consistency of measurement between both modes of assessment. The successful evaluation of the physical outcome measure of knee range of motion via the Internet assists the further development of Internet-based physiotherapy applications.     

Can the rasp be used to predict intra-operatively the primary stability that can be achieved by press-fitting the stem in cementless hip arthroplasty?

BACKGROUND: Success of cementless hip stems implantation depends mainly on primary stability which, in turn, depends on the degree of press-fitting achieved, and optimal medullary canal filling by the selected stem size. Stem size, based on templating and pre-operative planning software, only partially avoids stem mis-sizing. Mis-sizing can produce implant instability and/or wasting the wrong-sized stem. METHODS: An intra-operative device was designed that enabled real-time measurement of rasp-bone micromotions by applying torque manually. Rasp stability was assessed in vitro in seven femurs after femoral canal preparation when the rasp was fully seated. Then, primary implant stability was assessed with the stem press-fitted in the position indicated as optimal by the surgeon. Torque-micromotion curves were compared for the rasp and the stem. Finally, the protocol was applied to two hip patients. FINDINGS: Rasp stability micromotions were successfully measured in all in vitro specimens and all patients. The slope of the initial part of the rasp torque-micromotion curve was correlated with the slope of the stem curve (correlation coefficient=0.798, P-value=0.001). The entire procedure for measuring rasp stability added less than two minutes to the 75-80-min operating time. INTERPRETATION: This study indicates that the rasp stability can be used to predict the maximal primary stability that can eventually be achieved by the selected stem size. Early prediction of stem stability enables correcting the stem size, if necessary, before the press-fitting procedure is initiated, thus saving operating time and the cost of a new stem.     

Can external and subjective information ever be used to reduce the size of randomised controlled trials?

In the design of randomised trials in rare cancers, a Bayesian approach has been advocated, which allows for external and subjective information to be formally incorporated. We explore whether this can be extended more generally to allow for smaller trials to be conducted using a case study involving a trial of nasopharyngeal carcinoma. The external information available at various points during the trial is first summarised in the form of 'prior distributions'. Each of these is then combined with the accumulated data from the trial at that point in time to form 'posterior distributions', from which conclusions are drawn. We have argued that such a framework for the design, analysis and interpretation of a randomised trial in the light of external evidence is particularly useful in situations such as trials in rare cancers. But more generally, it may potentially also allow for smaller trials to be conducted. Although, at this point in time, we are hesitant to recommend the full implementation of the Bayesian methodology to modify the (conventionally) planned trial size we submit that a formal synthesis of the external evidence bearing on the question of concern is a valuable exercise in itself.     

Can MDIs be used effectively by extubated ICU patients?

Metered-dose inhaler (MDI) therapy can be an effective, cost-efficient means of managing chronic airway obstruction in many patients in medical or surgical intensive care units who have recently been extubated. Because medication is delivered directly to the airways through an MDI, a relatively low dosage may be effective, and few adverse effects may be encountered. Candidates for MDI therapy should have a vital capacity of at least 900 mL, be able to hold their breath for at least 5 seconds, and have a respiratory rate of under 25 breaths per minute. The majority of patients who meet these criteria are able to convert to MDI therapy within 24 hours of extubation.     

Can the Hospital Anxiety and Depression Scale be used in patients with schizophrenia?

Rationale, aims, objectives The Hospital Anxiety and Depression Scale (HADS) was developed explicitly for use in non‐psychotic populations, yet is routinely used for screening patients with psychotic illness. The utility of the HADS as a screening instrument for use in patients with schizophrenia was investigated. Method Exploratory factor analysis and confirmatory factor analysis were conducted on the HADS to determine its psychometric properties in 100 patients with a primary ICD‐10 diagnosis of schizophrenia. Results Three distinct factors were identified within the HADS. Support was found for the clinical use of the HADS anxiety subscale to assess anxiety in patients with schizophrenia; however, evidence was also found that the HADS depression subscale may not be a unidimensional measure of depression in this clinical group. Conclusions Caution should be used when using the HADS depression subscale in this clinical group. The direction of future research in this area is indicated, in particular comparison of HADS anxiety and depression measures to determine further the validity or otherwise of these subscale domains.     

Can the LANSS scale be used to classify pain in chronic cancer pain trials?

Purpose

The Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) scale was developed to differentiate pain of predominantly neuropathic or nociceptive origin. The aim of this study was to determine whether the LANSS scale was an appropriate tool to classify pain in a trial of patients with advanced cancer and chronic refractory pain.

Methods

Clinician assessment of pain type (neuropathic or nociceptive) was used to determine the sensitivity and specificity of LANSS scores in 112 trial participants. Those classified as "mixed" or of uncertain aetiology were excluded. We undertook several analyses in an attempt to improve the LANSS scale and better diagnose pain type for our specific dataset.

Results

There was strong association between the LANSS score and a diagnosis of neuropathic versus nociceptive pain, p?<?0.001. When the clinical assessment was compared with the LANSS scale, the overall accuracy was 94 % (79/84). The 5 false negatives and no false positives resulted in a sensitivity of 0.86 (0.70, 0.95), specificity of 1 (0.93, 1), positive predictive value of 1 (0.88, 1) and negative predictive value of 0.91 (0.80, 0.97). The negative likelihood ratio was 0.14 (0, 0.32). The scale had good discriminant and construct validity. Reliability was assessed via internal consistency with Cronbach's α?=?0.76, similar to that of the original validation study (α?=?0.74). None of the new scales developed was better at differentiating pain type.

Conclusions

The LANSS scale predicted well for pain type in a cancer population and is a useful tool for classifying pain in cancer pain trials.     

Can MR elastography be used to measure liver stiffness in patients with iron overload?

Untreated hepatic iron overload causes hepatic fibrosis and cirrhosis and can predispose to hepatocellular carcinoma. MR elastography (MRE) provides a non-invasive means to measure liver stiffness, which correlates with liver fibrosis but standard gradient recalled echo (GRE)-based MRE techniques fail in patients with high iron due to very low hepatic signal. Short echo time (TE) 2D spin echo echoplanar imaging (SE-EPI)-based MRE may allow measurement of stiffness in the iron loaded liver. The purpose of this study was to describe the use of such an MRE sequence in patients undergoing liver iron quantification by MRI. In our preliminary study of 43 patients with mean LIC of 9.3 mg/g (range 1.8–21.5 mg/g), liver stiffness measurements could be made in 77% (33/43) of patients with a short TE, SE-EPI based MRE sequence. On average, mean LIC in patients with failed MRE was higher than in those with successful MRE (15.9 mg/g dry weight vs. 7.3 mg/g), but a cut-off value for successful MRE could not be established. Seven patients (21% of those with successful MRE) had liver stiffness values suggestive of the presence of significant fibrosis (> 2.49 kPa). A short TE, SE-EPI based MR elastography sequence allows successful measurement of liver stiffness in a majority of patients with liver iron loading, potentially allowing non-invasive screening for fibrosis.