The effect of supine versus upright patient positioning on inferior vena cava metrics.

BACKGROUND: Ultrasound of the inferior vena cava (IVC) is a noninvasive and rapidly obtainable method of intravascular volume assessment; however not all patients can lie supine for this procedure. In this study we assess whether patient positioning affects IVC diameter metrics. METHODS: This was a prospective convenience sample of patients in an in-patient dialysis unit at an urban tertiary care center. IVC metrics taken in the supine patient, and then at 45o semi-upright position, pre and post dialysis. Measurements were taken in M-mode in longitudinal plane roughly 2 cm below the level of the diaphragm. IVC-maximum and IVC-minimum diameter measurements were used to determine the IVC collapse index (IVC Max - IVC Min)/IVC Max). Statistics such as means, frequencies and percentages, intraclass correlation coefficient and Bland Altman summary statistics were calculated. RESULTS: Forty-five patients were enrolled. Average age was 57 years, 69% were male, 73% were African American, 82% had hypertension, 42% had diabetes. There was good to excellent agreement between supine and upright IVC measurements. Both the IVC minimum and maximum measurements had similar coefficient correlation (ri) measurements (0.917 and 0.890 respectively), whereas agreement in the collapse index was lower (ri = 0.813). Bland Altman analysis demonstrated excellent agreement and small 95% limits of agreement (±6 mm) with minimal mean bias for both the minimum and maximum measurements. CONCLUSION: IVC metrics do not change significantly based on patient position. For those patients who are unable to lay completely supine, a semi-upright measurement of the IVC for volume status may be an accurate alternative.

Screening for Syphilis in Cases of Suspected Gonorrhea and Chlamydia Infections.

Background. In all cases of suspected sexually transmitted infections (STIs), it has been routine practice to screen for syphilis with a blood sample. The incidence of syphilis seems to be lower than that of commonly screened STIs. Objective. The objective of our study was to determine whether it is cost-effective to screen for syphilis with serological testing in cases of suspected gonorrhea and chlamydia infections. Hypothesis. Our hypothesis is that it is not cost-effective to screen for syphilis in cases of presumed gonorrhea and chlamydia infections. Methods. Our study is a New York Medical College institutional review board-approved retrospective study. During the period January 2004 to August 12, 2006, the laboratory work of all patients tested for gonorrhea and chlamydia in our emergency department was reviewed. The charts were reviewed for the following tests: gonorrhea DNA probe, chlamydia DNA probe, and syphilis IgG (immunoglobulin G)/RPR (rapid plasma reagin). The results of these tests were obtained and analyzed. Results. The total number of patients screened for gonorrhea and chlamydia during this period was 196. Seventy-eight patients tested positive for gonorrhea and chlamydia. All these 78 patients, tested negative for syphilis. The overall prevalence of positivity for STIs was 39.8% (78/196). The prevalence of chlamydia alone was 85.9% (67/78) and gonorrhea alone was 7.69% (6/78). The prevalence of combined both chlamydia and gonorrhea was 6.4% (5/78). Statistics. We used online SILICO 2 × 4 Fisher exact test. By comparing positive and negative results of serology RPR, GC, and chlamydia trap, the resultant 2-tailed P value is <.0001, which is statistically significant. Conclusions. Per our study, the yield of syphilis testing was negligible. It may not be cost-effective to screen for syphilis in cases of STIs such as gonorrhea and chlamydia.