The authors describe 2 efficiency (planned missing data) designs for measurement: the 3-form design and the 2-method measurement design. The 3-form design, a kind of matrix sampling, allows researchers to leverage limited resources to collect data for 33% more survey questions than can be answered by any 1 respondent. Power tables for estimating correlation effects illustrate the benefit of this design. The 2-method measurement design involves a relatively cheap, less valid measure of a construct and an expensive, more valid measure of the same construct. The cost effectiveness of this design stems from the fact that few cases have both measures, and many cases have just the cheap measure. With 3 brief simulations involving structural equation models, the authors show that compared with the same-cost complete cases design, a 2-method measurement design yields lower standard errors and a higher effective sample size for testing important study parameters. With a large cost differential between cheap and expensive measures and small effect sizes, the benefits of the design can be enormous. Strategies for using these 2 designs are suggested.
The incidence of infection in ECMO patients at our institution has not increased significantly since our previous study. Cardiac patients have increased risk for nosocomial infection while on ECMO, which may be in part due to longer cannulation times, as well as increased likelihood of undergoing major procedures or having an open chest.
tatistical procedures for handling missing data are becoming increasingly common in a wide range of social research. Schafer's (1997) NORM software S for multiple imputation has been available for some time as a stand-alone Microsoft Windows application, and several articles and chapters have been written describing its use (Schafer
Outcomes of patients transported by an experienced extracorporeal membrane oxygenation team to a busy extracorporeal membrane oxygenation center are very comparable to outcomes of nontransported extracorporeal membrane oxygenation patients as reported in the Extracorporeal Life Support Organization registry. As has been previously reported, interhospital extracorporeal membrane oxygenation transport is feasible and can be accomplished safely. Other experienced extracorporeal membrane oxygenation centers may want to consider developing interhospital extracorporeal membrane oxygenation transport capabilities to better serve patients in different geographic regions.
Documentation of postoperative pain assessment and management in neonates was extremely variable among the participating hospitals. Pain assessment by physicians must be emphasized, in addition to developing evidence-based guidelines for postoperative care and educating professional staff to improve postoperative pain control in neonates.
Ultrasound (US)-guided transvaginal needle or catheter drainage was performed in 14 women for a variety of pelvic abscesses and fluid collections; tubo-ovarian abscesses and postoperative collections were most common. Diagnosis was achieved in all 14 patients (100%), including one patient with suspected ovarian carcinoma who underwent only diagnostic needle aspiration and no therapeutic drainage. Abscesses or fluid collections were evacuated in 13 of 13 patients (100%) with either needle (n = 7) or catheter (n = 6) drainage (with appropriate antibiotics). Twelve of the 14 patients (86%) were spared an operation; surgery was undertaken in two patients for a persistent tubo-ovarian phlegmon. No major complications were associated with drainage. Catheters were removed an average of 6.7 days after insertion. The success, safety, and advantages of US-guided transvaginal drainage in our early experience suggest its use as an alternative to standard percutaneous catheter procedures to diagnose and drain certain pelvic abscesses and fluid collections.
This study was conducted to determine if the resistive index (RI) could be used for the examination and follow-up of neonates with increased intracranial pressure. First, in a laboratory model with four mongrel dogs, RI was found to correlate linearly with cerebral perfusion pressure. Second, RI was studied in 57 healthy neonates and 285 neonates with abnormal clinical or head ultrasound findings. Average RI for healthy newborns was 75 +/- 10 and was inversely related to gestational age. RI in newborns with abnormal findings was uniformly elevated, but these values varied considerably and were not statistically different from normal values. Third, the RI was found to decrease significantly after patent ductus arteriosus ligation, tapping of subdural effusions, ventricular tapping (later cerebrospinal fluid shunting led to a further drop in RI), and ventriculoperitoneal shunting. Elevated RI indicates possible intra- or extracranial abnormality affecting cerebral blood flow. Doppler RI is valuable in following up neonates with abnormal or unstable conditions and in assessing the effectiveness of therapies to improve cerebral perfusion.
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