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221: Evaluation of Ectopic Pregnancy With Bedside Ultrasound by Emergency Physicians: A Meta-Analysis
Research Forum Abstracts
221
Evaluation of Ectopic Pregnancy With Bedside Ultrasound by Emergency Physicians: A MetaAnalysis
Stein JC, Wang R, Adler N, Goldstein R, McAlpine I, Won G, Jacoby V, Kohn M/ University of California, San Francisco, CA
Study Objectives: Early and accurate recognition of ectopic pregnancy (EP) is essential to avoid morbidity and mortality. Research and clinical practice have demonstrated a clear role for pelvic ultrasound examination in patients at risk for EP. Such evaluations have typically been performed by radiologist or OB/GYN consultants. Several studies have investigated the accuracy of pelvic ultrasound by emergency physicians. These studies have generally shown both high sensitivity and negative predictive value for ruling out EP. It has been demonstrated that this approach is cost effective, and decreases the time patients spend in the ED. However, these accuracy studies have been relatively small with wide confidence intervals around the performance estimates, perpetuating uncertainty regarding the appropriate role of this technology. In order to better assess overall test characteristics of the use of pelvic ultrasound by emergency physicians in the evaluation of EP, we conducted a systematic review and meta-analysis. Methods: A structured search was performed of both MEDLINE and EMBASE from 1966 through August 2008. The search string utilized the following subject terms and text words: “ectopic pregnancy,” “ultrasound or ultrasonography or sonography,” and “emergency.” The search was limited to human subjects, and included all languages. We conducted online bibliographic searches of abstract submissions to Annals of Emergency Medicine and Academic Emergency Medicine from 1990 through August 2008. Additionally, we searched through the bibliographies of studies that met relevance criteria for further articles on the subject. Two independent reviewers screened all abstracts and subsequent manuscripts for inclusion using the following criteria: 1) original research of female emergency department patients at risk for EP, 2) emergency physician performed and interpreted the initial pelvic ultrasound, 3) a gold standard follow-up criterion (formal radiology or clinical) was used for all patients. Two independent reviewers then extracted data from the included studies, and standardized the testing vocabulary such that a negative study for emergency physician was a definite intrauterine pregnancy (gestational sac plus yolk sac and/or fetal pole). Study quality was assessed utilizing a validated tool for quality assessment of diagnostic accuracy studies (QUADAS). Pooled data was analyzed with a random effects model. Results: The initial search yielded 576 publications. Abstract review yielded 57 with potential relevance. After full manuscript review, final inclusion yielded eight articles and one abstract for a total of 1987 patients (99% agreement, kappa 0.95). Our random effects model of the sensitivity demonstrated homogeneity and showed a pooled estimate of 99.3% (95% CI: 96.5 to 100). The model also demonstrated homogeneity for negative predictive value, with overall estimate of 99.96% (95% CI: 99.6 to 100). For both specificity and positive predictive value, there was significant heterogeneity. Overall, emergency physicians were able to rule out emergency physician in 63% of patients. Conclusions: This systematic review demonstrates that studies of the use of bedside ultrasound performed by emergency physicians consistently demonstrate excellent sensitivity and negative predictive value for ruling out ectopic pregnancy in a wide variety of clinical settings.
222
Nurse Utilization of Ultrasound Guidance for Peripheral IV Placement in the Emergency Department: Does It Change Over Time?
Lyon M, Sinex JE, Shiver SA, Bloch A, Flake M/Medical College of Georgia, Augusta, GA
Study Objectives: Nurse utilization of ultrasound (US) for peripheral intravenous (PIV) access has been increasing, particularly in academic medical centers. However, little is known about how the frequency of use of this technique changes over time following initial adoption within an institution. Our objective is to describe the utilization of US for PIV access over time in a well-developed nursing based program. Methods: This was a prospective observational trial performed in a Level I academic ED. Nurses, both RN and LPN, trained in US-guided PIV access recorded their use of and indications for the procedure for quality assurance purposes. A 5month sample period in 2008 was compared to a similar 5-month sample period in 2003. The data were evaluated using descriptive techniques. Results: ED volume was comparable between the two study periods (75,000 vs. 78,000, respectively), as was nurse staffing (105.6 vs. 120.4 FTE). During the 2003 time period, 10 nurses were trained (6.4%), and during the 2008 time period 30 nurses had
Volume , . : September
attended training (25%). The 2003 time period yielded 321 US-guided PIV access procedures by 7 nurses (70% of the trained staff ), and the 2008 time period yielded 217 US-guided PIV access procedures by 18 nurses (60% of the trained staff). In the most recent study period, 48.8% of US-guided PIV access procedures were performed by 2 nurses and 89.8% of procedures were performed by 7 nurses. During the 2003 time period, procedures were equally divided among the 7 users. The most common reasons given for using US during either time period were prior failed access (60.4%), need for large bore PIV access for IV contrast or resuscitation (24.4%), or a physical examination consistent with poor venous access (22.6%). Conclusion: US-guided PIV placement by nurses can be described as being performed by a relatively small core cadre of users who employ US relatively frequently, and a larger group who use it rarely. It was further observed that the overall number of procedures did not increase over time, though the number of nurses employing this technique did increase. Further research is needed to define the barriers to implementation of the technique after training.
223
Emergency Department Bedside Ultrasound Measurement of Caval Index as Non-Invasive Determination of Low Central Venous Pressure: A Multi-Center Validation of an Emergency Department Protocol
Hansen AV, Medak AJ, Campbell C, Nagdev A, Castillo EM/University of California - San Diego, San Diego, CA; Highland General Hospital, Oakland, CA
Study Objectives: An initial study has shown that among critically ill adult emergency department (ED) patients undergoing central venous catheterization, a greater than 50% decrease in the inferior vena cava (IVC) diameter measured by experienced emergency physician sonographers is a good predictor of low central venous pressure (CVP). This is preliminary data from a study that seeks to validate this protocol at an additional center among emergency physician sonographers of varying experience. Methods: Critically ill adult ED patients undergoing central venous catherization were enrolled in a prospective, observational study. Their maximal inspiratory (IVCi) and expiratory (IVCe) IVC diameters were measured by two-dimensional bedside ultrasound completed by emergency medicine residents and attendings of varying ED ultrasound experience. Prior to measurement of a transduced CVP, emergency physician sonographers were also asked to estimate the CVP as ⬎ or ⬍ 8mm Hg by visually estimating respiratory variation of the IVC diameter. The caval index (CI) was calculated as the relative decrease in IVC diameter over one respiratory cycle (IVCe–IVCi/IVCe). Linear regression was used to assess the association of CVP and CI. The sensitivity, specificity, positive (PPV) and negative (NPV) predictive values and 95% confidence intervals of a CI ⱖ 50% to predict a CVP ⬍ 8 mm Hg were estimated. These characteristics were also estimated for the emergency physician sonographer’s ability to predict a CVP ⬍ 8 mm Hg based on visual estimation of inspiratory collapse of the IVC. Results: 25 patients have been enrolled; however, 1 patient was excluded as the operator was unable to locate the IVC. 12.5% of operators were second year residents, 41.7% were third year residents, 16.7% were fourth year residents and 29.2% were attending emergency physicians. Of 24 patients, the median age was 56 and 58% were female. Mean time and fluid administered from ultrasound measurement to CVP determination was 18 minutes and 10 mL, respectively. 50% of the patients had had a measured CVP less than 8 mm Hg. The relationship between CI and CVP in an unadjusted linear regression model was : ⫺.12 (95% CI: ⫺0.23, ⫺.010). The sensitivity of a CI ⱖ 50% to predict a CVP ⬍ 8 mm Hg was 60% (24.7– 86.3%), specificity was 85.7% (56.2–97.5%), PPV was 75% (35.6 –95.5%), NPV was 75% (47.4 –91.7%). The sensitivity of emergency physician sonographer estimated CVP ⬍ 8 mm Hg to predict an actual CVP ⬍ 8 mm Hg was 90% (54.1–99.5%), specificity was 78.6% (48.8 –94.3%), PPV was 75% (42.8 ⫺93.3%), NPV was 91.6% (59.8 –99.6%). Conclusions: These preliminary data suggest that a protocol in which emergency physician bedside ultrasound measurement of CI ⱖ 50% has shown to be a good noninvasive predictor of low CVP may be validated when performed by emergency physician ultrasonographers of varying experience. In particular, clinician estimated CVP ⬍ 8 mm Hg based on bedside ultrasound appears to be a good predictor of a low CVP. Rapid, bedside measurements of CI could be a useful guide in the resuscitative management of critically ill patients.
Annals of Emergency Medicine S69
221
Evaluation of Ectopic Pregnancy With Bedside Ultrasound by Emergency Physicians: A MetaAnalysis
Stein JC, Wang R, Adler N, Goldstein R, McAlpine I, Won G, Jacoby V, Kohn M/ University of California, San Francisco, CA
Study Objectives: Early and accurate recognition of ectopic pregnancy (EP) is essential to avoid morbidity and mortality. Research and clinical practice have demonstrated a clear role for pelvic ultrasound examination in patients at risk for EP. Such evaluations have typically been performed by radiologist or OB/GYN consultants. Several studies have investigated the accuracy of pelvic ultrasound by emergency physicians. These studies have generally shown both high sensitivity and negative predictive value for ruling out EP. It has been demonstrated that this approach is cost effective, and decreases the time patients spend in the ED. However, these accuracy studies have been relatively small with wide confidence intervals around the performance estimates, perpetuating uncertainty regarding the appropriate role of this technology. In order to better assess overall test characteristics of the use of pelvic ultrasound by emergency physicians in the evaluation of EP, we conducted a systematic review and meta-analysis. Methods: A structured search was performed of both MEDLINE and EMBASE from 1966 through August 2008. The search string utilized the following subject terms and text words: “ectopic pregnancy,” “ultrasound or ultrasonography or sonography,” and “emergency.” The search was limited to human subjects, and included all languages. We conducted online bibliographic searches of abstract submissions to Annals of Emergency Medicine and Academic Emergency Medicine from 1990 through August 2008. Additionally, we searched through the bibliographies of studies that met relevance criteria for further articles on the subject. Two independent reviewers screened all abstracts and subsequent manuscripts for inclusion using the following criteria: 1) original research of female emergency department patients at risk for EP, 2) emergency physician performed and interpreted the initial pelvic ultrasound, 3) a gold standard follow-up criterion (formal radiology or clinical) was used for all patients. Two independent reviewers then extracted data from the included studies, and standardized the testing vocabulary such that a negative study for emergency physician was a definite intrauterine pregnancy (gestational sac plus yolk sac and/or fetal pole). Study quality was assessed utilizing a validated tool for quality assessment of diagnostic accuracy studies (QUADAS). Pooled data was analyzed with a random effects model. Results: The initial search yielded 576 publications. Abstract review yielded 57 with potential relevance. After full manuscript review, final inclusion yielded eight articles and one abstract for a total of 1987 patients (99% agreement, kappa 0.95). Our random effects model of the sensitivity demonstrated homogeneity and showed a pooled estimate of 99.3% (95% CI: 96.5 to 100). The model also demonstrated homogeneity for negative predictive value, with overall estimate of 99.96% (95% CI: 99.6 to 100). For both specificity and positive predictive value, there was significant heterogeneity. Overall, emergency physicians were able to rule out emergency physician in 63% of patients. Conclusions: This systematic review demonstrates that studies of the use of bedside ultrasound performed by emergency physicians consistently demonstrate excellent sensitivity and negative predictive value for ruling out ectopic pregnancy in a wide variety of clinical settings.
222
Nurse Utilization of Ultrasound Guidance for Peripheral IV Placement in the Emergency Department: Does It Change Over Time?
Lyon M, Sinex JE, Shiver SA, Bloch A, Flake M/Medical College of Georgia, Augusta, GA
Study Objectives: Nurse utilization of ultrasound (US) for peripheral intravenous (PIV) access has been increasing, particularly in academic medical centers. However, little is known about how the frequency of use of this technique changes over time following initial adoption within an institution. Our objective is to describe the utilization of US for PIV access over time in a well-developed nursing based program. Methods: This was a prospective observational trial performed in a Level I academic ED. Nurses, both RN and LPN, trained in US-guided PIV access recorded their use of and indications for the procedure for quality assurance purposes. A 5month sample period in 2008 was compared to a similar 5-month sample period in 2003. The data were evaluated using descriptive techniques. Results: ED volume was comparable between the two study periods (75,000 vs. 78,000, respectively), as was nurse staffing (105.6 vs. 120.4 FTE). During the 2003 time period, 10 nurses were trained (6.4%), and during the 2008 time period 30 nurses had
Volume , . : September
attended training (25%). The 2003 time period yielded 321 US-guided PIV access procedures by 7 nurses (70% of the trained staff ), and the 2008 time period yielded 217 US-guided PIV access procedures by 18 nurses (60% of the trained staff). In the most recent study period, 48.8% of US-guided PIV access procedures were performed by 2 nurses and 89.8% of procedures were performed by 7 nurses. During the 2003 time period, procedures were equally divided among the 7 users. The most common reasons given for using US during either time period were prior failed access (60.4%), need for large bore PIV access for IV contrast or resuscitation (24.4%), or a physical examination consistent with poor venous access (22.6%). Conclusion: US-guided PIV placement by nurses can be described as being performed by a relatively small core cadre of users who employ US relatively frequently, and a larger group who use it rarely. It was further observed that the overall number of procedures did not increase over time, though the number of nurses employing this technique did increase. Further research is needed to define the barriers to implementation of the technique after training.
223
Emergency Department Bedside Ultrasound Measurement of Caval Index as Non-Invasive Determination of Low Central Venous Pressure: A Multi-Center Validation of an Emergency Department Protocol
Hansen AV, Medak AJ, Campbell C, Nagdev A, Castillo EM/University of California - San Diego, San Diego, CA; Highland General Hospital, Oakland, CA
Study Objectives: An initial study has shown that among critically ill adult emergency department (ED) patients undergoing central venous catheterization, a greater than 50% decrease in the inferior vena cava (IVC) diameter measured by experienced emergency physician sonographers is a good predictor of low central venous pressure (CVP). This is preliminary data from a study that seeks to validate this protocol at an additional center among emergency physician sonographers of varying experience. Methods: Critically ill adult ED patients undergoing central venous catherization were enrolled in a prospective, observational study. Their maximal inspiratory (IVCi) and expiratory (IVCe) IVC diameters were measured by two-dimensional bedside ultrasound completed by emergency medicine residents and attendings of varying ED ultrasound experience. Prior to measurement of a transduced CVP, emergency physician sonographers were also asked to estimate the CVP as ⬎ or ⬍ 8mm Hg by visually estimating respiratory variation of the IVC diameter. The caval index (CI) was calculated as the relative decrease in IVC diameter over one respiratory cycle (IVCe–IVCi/IVCe). Linear regression was used to assess the association of CVP and CI. The sensitivity, specificity, positive (PPV) and negative (NPV) predictive values and 95% confidence intervals of a CI ⱖ 50% to predict a CVP ⬍ 8 mm Hg were estimated. These characteristics were also estimated for the emergency physician sonographer’s ability to predict a CVP ⬍ 8 mm Hg based on visual estimation of inspiratory collapse of the IVC. Results: 25 patients have been enrolled; however, 1 patient was excluded as the operator was unable to locate the IVC. 12.5% of operators were second year residents, 41.7% were third year residents, 16.7% were fourth year residents and 29.2% were attending emergency physicians. Of 24 patients, the median age was 56 and 58% were female. Mean time and fluid administered from ultrasound measurement to CVP determination was 18 minutes and 10 mL, respectively. 50% of the patients had had a measured CVP less than 8 mm Hg. The relationship between CI and CVP in an unadjusted linear regression model was : ⫺.12 (95% CI: ⫺0.23, ⫺.010). The sensitivity of a CI ⱖ 50% to predict a CVP ⬍ 8 mm Hg was 60% (24.7– 86.3%), specificity was 85.7% (56.2–97.5%), PPV was 75% (35.6 –95.5%), NPV was 75% (47.4 –91.7%). The sensitivity of emergency physician sonographer estimated CVP ⬍ 8 mm Hg to predict an actual CVP ⬍ 8 mm Hg was 90% (54.1–99.5%), specificity was 78.6% (48.8 –94.3%), PPV was 75% (42.8 ⫺93.3%), NPV was 91.6% (59.8 –99.6%). Conclusions: These preliminary data suggest that a protocol in which emergency physician bedside ultrasound measurement of CI ⱖ 50% has shown to be a good noninvasive predictor of low CVP may be validated when performed by emergency physician ultrasonographers of varying experience. In particular, clinician estimated CVP ⬍ 8 mm Hg based on bedside ultrasound appears to be a good predictor of a low CVP. Rapid, bedside measurements of CI could be a useful guide in the resuscitative management of critically ill patients.
Annals of Emergency Medicine S69