Development of an Emergency Department Surge Plan Based on the NEDOCS score.

Context: Emergency Department (ED) overcrowding is a significant problem worldwide. Many factors contribute to ED overcrowding, including staffing shortages, diagnostic testing delays, and inadequate inpatient beds to meet the demand. ED overcrowding results in patient safety issues like higher inpatient mortality and other negative impacts, such as an increased length of stay (LOS) and an increased trend of leaving the ED before undergoing an evaluation and treatment. The National emergency department overcrowding study (NEDOCS) is a scoring system to detect ED overcrowding objectively. Objective: To determine the impact of implementing an ED adult surge plan on ED throughput. Study Design: Prospective single-site study of adults presenting to the ED from January to April 2023. Setting or Dataset: Academic medical center. Population studied: Adult ED patients. Outcome Measures: Mean adult ED hold times, mean ED LOS, left without seen rate, mean door-to-doctor exam time, mean NEDOCS scores. Results: This analysis included 16,701 ED visits and 12,269 patients. During this time, 3,751 (22.5%) patients were admitted to inpatient status, and 1,413 (8.5%) were admitted to observation status. Pre-implementation, the mean ED hold time was 9.9 hours which decreased to 5.7 hours post-implementation (p=0.03). Pre-implementation, the mean ED LOS was 15.4 hours which decreased to 14.1 hours post-implementation (p=ns). Pre-implementation, the left without being seen rate was 4.8%, which decreased to 4.0% post-implementation (p=ns). Pre-implementation, the mean door-to-doctor exam time was 57.6 minutes which decreased to 54.0 minutes postimplementation (p=ns). Pre-implementation, the mean NEDOCS score was 186.2, which decreased to 131.2 post-implementation (p<0.0001). Conclusions: Our study suggests that implementing an ED adult surge plan can significantly improve ED hold hours and NEDOCS scores. However, it is important to note that other important ED throughput metrics (mean ED LOS, left without seen rate, mean door-to-doctor exam time) did not significantly improve. Further research may be necessary to understand the factors contributing to these outcomes and identify additional interventions that may improve ED throughput.

Clinical Outcomes of a Newly Instituted Hospital at Home Program During the COVID19 Pandemic.

Context: The COVID19 pandemic stressed U.S. health systems beyond their capacity and created worsening clinical outcomes. Hospital a Home (HaH) programs were utilized infrequently prior to pandemic. The Acute Care at Home Waiver was introduced in 2020 to facilitate the creation of HaH programs with a goal of promoting treatment in the home setting. A potential alternative approach to creating rapid inpatient level health system capacity is providing hospital-level care at home to substitute for inpatient hospitalization. The overall impact on clinical outcomes of a HaH program in patients with COVID19 is not well understood. Objective: To compare clinical outcomes of a HaH program versus usual hospital care for patients admitted for COVID19. Study Design: Matched case-control retrospective chart review. Setting or Dataset: Academic medical center. Population studied: Patients admitted with COVID19 and subsequently enrolled into the HaH program from February 1, 2021 to January 31, 2022. Patients aged <18 were excluded from consideration for enrollment. A case-control sample was matched on age, gender, and severity of illness. A total of 200 patients (100 HaH and 100 control) were included for analysis. Outcome Measures: Primary outcome: 30-day readmissions, Secondary outcomes: Inpatient length of stay (iLOS) defined as length of stay in the physical hospital, total length of stay (tLOS) (sum of iLOS and HaH program days), time to readmission, and 30-day emergency department visits. Results: Analysis included 200 patents. The mean age was 50.4. The sample was 55% female. 48.5% were black, 43.5% were white, and 8% were other races. Compared with usual care patients, HaH patients had no difference in 30-day readmissions (11% vs. 14%, p=0.648), mean days to readmission (9.0 vs. 11.8, p=0.201), or return ED visits (17% vs. 20%, p=0.701). Inpatient LOS (5.7 vs. 9.4 days, p=0.005) was shorter in the HaH group. Total LOS (13.0 vs. 9.4 days, p<0. 001) was longer in the HaH group. Conclusions: The HaH program was associated with no difference in readmissions, time to readmission, or return ED visits compared to usual hospital care. HaH programs were associated with shorter inpatient length of stays, but longer total length of stays. In surge times, HaH programs could potentially reduce iLOS and increase bed capacity. Future studies should look to evaluate the economic impact of HaH programs and investigate the drivers of the increased tLOS.

The Use of the Abdominal Aortic and Junctional Tourniquet Versus Combat Gauze in a Porcine Hemicorporectomy Model.

BACKGROUND: Junctional hemorrhage is a potentially preventable cause of death. The Abdominal Aortic and Junctional Tourniquet (AAJT) compresses major vascular structures and arrests blood flow in exsanguinating hemorrhage. In a human model, the AAJT was effective in stopping blood flow in the femoral arteries via compression of the distal aorta. This study compares the ability of AAJT and Combat Gauze (CG) to stop hemorrhagic bleeding from a hemicorporectomy in a swine model. METHOD: Six anesthetized swine were used. Carotid arterial catheters were placed for continuous mean arterial pressure (MAP) readings. A hemicorporectomy was accomplished with a blade lever device by cutting the animal through both femoral heads transecting the proximal iliac arteries and veins. Hemorrhage control was attempted with the AAJT and regular Kerlix gauze or CG packing and direct pressure followed by Kerlix gauze placed over the CG. The primary outcome measure was survival at 60 minutes. RESULTS: The 60-minute survival was 100% for the AAJT and 0% for the CG group. During the 60-minute monitoring period, only one CG animal achieved hemostasis. For the AAJT group, the mean time to hemostasis was 30 seconds. Initial MAP was higher in the AAJT group (mean, 87mmHg) than the CG group (mean, 70mmHg). The mean 60-minute MAP was 73mmHg for the AAJT group. Mean blood loss at 5 minutes and mean total blood loss were greater in the CG group than in the AAJT group. CONCLUSION: AAJT is superior to CG in controlling hemorrhage in a junctional wound in a swine model.

Transfer of real-time ultrasound video of FAST examinations from a simulated disaster scene via a mobile phone.

OBJECTIVE: Disaster management is a complex and difficult undertaking that may involve limited health care resources and evaluation of multiple victims. The objectives of this study were to evaluate the feasibility of real-time ultrasound video transmission from a simulated disaster triage location via commercially available video mobile phones and assess the ability of emergency physicians to accurately interpret the transmitted video of Focused Assessment with Sonography for Trauma (FAST) ultrasound examinations. METHODS: This was a prospective, observational study that took place at a simulated disaster scene put on for an Advanced Disaster Life Support (ADLS) course. The second component occurred at a Level I academic urban emergency department (ED) with an annual census of 78,000. Nineteen subjects at a simulated disaster scene were scanned using a SonoSite Titan ultrasound system (Bothell, Washington USA). An off-the-shelf, basic, video-capable mobile phone was used to record each ultrasound examination; and then immediately transmit the videos to another mobile phone approximately 170 miles away. The transmitted video was received by three emergency physicians with hospital credentialing in emergency ultrasound. Each FAST examination video was assessed for pathology, such as free fluid. The reviewers graded the image quality and documented the overall confidence level regarding whether or not a complete and adequate examination was visualized. Spearman's rank correlation coefficient was used to examine the agreement between the reviewers and the sonologist who performed the ultrasound examinations. RESULTS: A total of 19 videos were transmitted. The median time for transmission of a video was 82.5 seconds (95% CI, 67.7 seconds-97.3 seconds). No video failed to transmit correctly on the first attempt. The image quality ratings for the three reviewers were 7.7, 7.5, and 7.4 on a 10-point Likert scale. There was a moderate agreement between the reviewers and sonologist in image quality rating and overall confidence level scores (rho = 0.6). CONCLUSIONS: Real-time portable ultrasound video transmission via commercially available video mobile phones from a simulated disaster triage location is feasible and emergency physicians were able to accurately interpret video of FAST ultrasound examinations.

Use of a novel abdominal aortic tourniquet to reduce or eliminate flow in the common femoral artery in human subjects.

BACKGROUND: Penetrating injuries of proximal femoral and iliac vessels are a common cause of death on the battlefield. Previous studies have shown that by applying 80 lb to 140 lb of pressure externally over the distal abdominal aorta, flow can be ceased in the common femoral artery (CFA). It has also been demonstrated that in a porcine model, an externally applied pneumatic abdominal aortic tourniquet (AAT) can occlude the aorta and inferior vena cava for 60 minutes without bowel injury or significant potassium elevations.The objectives of this study were (1) determine if AAT use in humans results in flow cessation in the CFA, (2) measure the pressure required to cease flow in the CFA, and (3) measure discomfort associated with application of the AAT. METHODS: Pulse wave Doppler measurements were taken in supine volunteers at the right CFA. The AAT was placed just above the iliac crests over the anterior abdomen. The AAT was inflated using a hand pump with an integrated manometer. Measurements were taken every 30 mm Hg. Discomfort was measured using a 10-point pain scale. RESULTS: In all subjects, flow was reduced in the CFA. Flow ceased in seven of nine subjects at a median pressure of 180 mm Hg (150-230 mm Hg). Median discomfort at ceasing of flow was 7 (3-10), returning to 0 after device removal. CONCLUSION: The AAT device was effective at reducing flow in the CFA and ceased flow in most of the subjects. Application of the device was associated with discomfort varying from moderate to severe and resolving with device removal.

M-mode ultrasound for the detection of pneumothorax during helicopter transport.

BACKGROUND: The presence of the sonographic sliding lung sign (SLS) is a sensitive indicator for the absence of a pneumothorax. The addition of M-mode ultrasound (US) can be a useful adjunct in detecting the SLS. OBJECTIVE: The objective of this study is to determine the feasibility of using M-mode US in evaluating the SLS during helicopter transport. METHODS: A model simulating human lung was used during image acquisition. M-mode images of the SLS were obtained during 3 distinct phases of transport: without rotor rotation, with rotor rotation while on the ground, and at level flight. Four US-credentialed emergency physicians evaluated M-mode US tracings of the model along with examples from human lungs, both with and without pneumothorax, in random fashion. RESULTS: A total of 104 images were reviewed (26 images per reviewer). All of the M-mode images were correctly identified. Motion artifact was noted on the M-mode tracings taken during rotor rotation, which was greatest during level flight. The rotor artifact was not felt to affect the diagnostic utility of the M-mode US tracing. CONCLUSION: M-mode US may be used successfully to detect the SLS during helicopter transport.

Ultrasound detection of the sliding lung sign by prehospital critical care providers.

BACKGROUND: The presence of the sonographic sliding lung sign (SLS) is a sensitive indicator for the absence of a pneumothorax. OBJECTIVE: The aim of this study was to determine if prehospital critical care providers (PHCPs) can acquire and maintain the necessary skills to determine the presence or absence of the SLS following a brief tutorial. METHODS: This was a blinded randomized observational trial using a cadaveric model. The model was randomized to esophageal intubation (negative SLS) or tracheal intubation (positive SLS), and a SonoSite 180 plus (Bothel, WA) machine was used for the examination. After a 9-month period, the PHCPs were reevaluated without additional instruction. RESULTS: There were 8 PHCPs. A total of 6 intubations were performed yielding a total of 48 trials. The presence or absence of the SLS was correctly identified in 46 of the 48 trials, resulting in a sensitivity and specificity of 96.9% (95% confidence interval [CI], 89.6%-99.1%) and 93.8% (95% CI, 93.8%-79.3%), respectively. At the 9-month follow-up, 7 of the original PHCPs were available to participate. A total of 8 intubations were performed yielding a total of 56 trials. The presence or absence of the SLS was correctly identified in all 56 trials, resulting in a sensitivity and specificity of 100% (95% CI, 93.6%-100%). CONCLUSION: Prehospital critical care providers can accurately determine the presence or absence of the sonographic SLS following a brief tutorial and retain the skill set following a 9-month interval.

Comparison of two packable hemostatic Gauze dressings in a porcine hemorrhage model.

BACKGROUND: Uncontrolled hemorrhage remains the primary cause of preventable battlefield mortality and a significant cause of domestic civilian mortality. Rapid hemorrhage control is crucial for survival. ChitoGauze and Combat Gauze are commercially available products marketed for rapid hemorrhage control. These products were selected because they are packable gauze that work via differing mechanisms of action (tissue adhesion versus procoagulant). OBJECTIVE: To compare the effectiveness of ChitoGauze and Combat Gauze in controlling arterial hemorrhage in a swine model. METHODS: Fourteen swine were studied. Following inguinal dissection and after achieving minimum hemodynamic parameters (mean arterial pressure [MAP] ≥ 70 mmHg), a femoral arterial injury was created using a 6-mm vascular punch. Free bleeding was allowed for 45 seconds, and then the wound was packed alternatively with ChitoGauze or Combat Gauze. Direct pressure was applied to the wound for 2 minutes, followed by a three-hour monitoring period. Resuscitation fluids were administered to maintain an MAP of ≥ 65 mmHg. Time to hemostasis, hemodynamic parameters, total blood loss, and amount of resuscitation fluid were recorded every 15 minutes. Data were analyzed using the Wilcoxon rank sum test. Histologic sections of the vessels were examined using regular and polarized light. RESULTS: No statistically significant differences were found between the groups regarding any measured end point. Data trends, however, favor ChitoGauze over Combat Gauze for time to hemostasis, fluid requirements, and blood loss. There was no evidence of retained foreign material on histologic analysis. CONCLUSION: ChitoGauze and Combat Gauze appear to be equally efficacious in their hemostatic properties, as demonstrated in a porcine hemorrhage model.

Prospective comparison of emergency physician-performed venous ultrasound and CT venography for deep venous thrombosis.

BACKGROUND: Venous thromboembolic disease is a major cause of mortality and morbidity. OBJECTIVES: The aim of this study is to compare emergency physician-performed ultrasound (EPPU) of the lower extremities with CT venography (CTV) in emergency department (ED) patients undergoing workup for pulmonary embolism (PE). METHODS: This was a prospective study performed at a busy academic ED. Adult patients (>18) undergoing workup for PE were eligible for the study; enrollment was based on a convenience sample, during hours worked by the investigators. Study patients underwent EPPU of the lower extremities followed by CT angiogram (CTA) of the chest and CTV of the lower extremities. Sensitivity and specificity of the ultrasound examination were calculated using CTV as the gold standard. RESULTS: A total of 61 patients were enrolled. Of 61 patients, 50 (82%; 95% confidence interval [CI], 72%-91%) had negative workups; 11 (18%; 95% CI, 8%-27%) were noted to have PE on CTA; 6 (10%; 95% CI, 2%-17%) were noted to have lower extremity deep venous thrombosis (DVT) on both EPPU and CTV evaluation; whereas 1 patient was found to have an external iliac DVT on CTV, which was not noted on EPPU. All patients with DVT (by either EPPU or CTV) were found to have PE on CTA. Sensitivity and specificity of EPPU when compared to CTV in the diagnosis of DVT was 86% (95% CI, 42%-99%) and 100% (95% CI, 91%-100%), respectively. CONCLUSIONS: Emergency physician-performed ultrasound produces results consistent with CTV in the diagnosis of femoropopliteal DVT. More proximal clots are not evaluated with EPPU and thus may result in a false negative.

Urethral obstruction due to the passage of a retained projectile into the genitounrinary system.

Urethral foreign bodies are relatively rare. When seen, they are usually the result of entry via the urethral meatus. Several reports in the literature have documented the passage of retained bullets into the genitourinary system. The vast majority of these were ultimately expelled spontaneously via the urethra. Very few cases of urethral obstruction and accompanying urinary retention due to bullet migration have been described. The presented case details distal urethral obstruction due to the migration of a retained firearm projectile presenting 1 month after initial gunshot wound. No such case exists in the emergency medicine literature.

Unusual presentation of acute ovarian torsion in an adolescent.

Ovarian torsion occurs when an ovary twists about its vascular pedicle. The process causes abdominal pain and will result in ovarian tissue loss if not diagnosed and managed expeditiously. Acute ovarian torsion is an uncommon cause of abdominal pain in adolescents, and, as a result, it is often mistaken for other processes. We present a case of ovarian torsion in an adolescent female who presented with abdominal pain and marked abdominal distension, which was initially suggestive of a gravid abdomen. She was ultimately found to have a very large cystic teratoma of the right ovary with concomitant ovarian torsion. There are no reported cases of ovarian cystic teratoma with acute torsion presenting with an abdominal mass suggestive of a gravid abdomen.

Acute lower extremity pain in an adult patient secondary to bilateral popliteal cysts.

Lower leg and calf pain is a common presenting complaint in the Emergency Department and may involve a variety of etiologies, including musculoskeletal and vascular pathology such as deep venous thrombosis. Baker's cysts are a periodic finding in patients suspected of having deep venous thrombosis. As more emergency physicians perform their own lower extremity ultrasound examinations, they encounter Baker's cysts as the cause of unilateral leg pain or swelling. Bilateral Baker's cysts are very rare and may present a diagnostic challenge in the Emergency Department if bedside ultrasound is not available. We present a case of bilateral Baker's cysts in a young dancer who presented complaining of bilateral lower extremity pain and upper calf swelling. The bilateral cysts were diagnosed on bedside ultrasound by the treating emergency physician and a disposition quickly made.

A prospective comparison of ultrasound-guided and blindly placed radial arterial catheters.

BACKGROUND: Arterial cannulation for continuous blood-pressure measurement and frequent arterial-blood sampling commonly are required in critically ill patients. OBJECTIVES: To compare ultrasound (US)-guided versus traditional palpation placement of arterial lines for time to placement, number of attempts, sites used, and complications. METHODS: This was a prospective, randomized interventional study at a Level 1 academic urban emergency department with an annual census of 78,000 patients. Patients were randomized to either palpation or US-guided groups. Inclusion criteria were any adult patient who required an arterial line according to the treating attending. Patients who had previous attempts at an arterial line during the visit, or who could not be randomized because of time constraints, were excluded. Enrollment was on a convenience basis, during hours worked by researchers over a six-month period. Patients in either group who had three failed attempts were rescued with the other technique for patient comfort. Statistical analysis included Fisher's exact, Mann-Whitney, and Student's t-tests. RESULTS: Sixty patients were enrolled, with 30 patients randomized to each group. Patients randomized to the US group had a shorter time required for arterial line placement (107 vs. 314 seconds; difference, 207 seconds; p = 0.0004), fewer placement attempts (1.2 vs. 2.2; difference, 1; p = 0.001), and fewer sites required for successful line placement (1.1 vs. 1.6; difference, 0.5; p = 0.001), as compared with the palpation group. CONCLUSIONS: In this study, US guidance for arterial cannulation was successful more frequently and it took less time to establish the arterial line as compared with the palpation method.

Control of hemorrhage in critical femoral or inguinal penetrating wounds--an ultrasound evaluation.

INTRODUCTION: Exsanguination from a femoral artery wound can occur in seconds and may be encountered more often due to increased use of body armor. Some military physicians teach compression of the distal abdominal aorta (AA) with a knee or a fist as a temporizing measure. OBJECTIVE: The objective of this study was to evaluate if complete collapse of the AA was feasible and with what weight it occurs. METHODS: This was a prospective, interventional study at a Level-I, academic, urban, emergency department with an annual census of 80,000 patients. Written, informed consent was obtained from nine male volunteers after Institutional Research Board approval. Any patient who presented with abdominal pain or had undergone previous abdominal surgery was excluded from the study. Subjects were placed supine on the floor to simulate an injured soldier. Various dumbbells of increasing weight were placed over the distal AA, and pulsed-wave Doppler measurements were taken at the right common femoral artery (CFA). Dumbbells were placed on top of a tightly bundled towel roughly the surface area of an adult knee. Flow measurements at the CFA were taken at increments of 20 pounds. This was repeated with weight over the proximal right artery iliac and distal right iliac artery to evaluate alternate sites. Descriptive statistics were utilized to evaluate the data. RESULTS: The mean velocity through the CFA was 75.8 cm/sec at 0 pounds. Compression of the AA ranging 80 to 140 pounds resulted in no flow in the CFA. A steady decrease in mean flow velocity was seen starting with 20 pounds. Flow velocity decreased more rapidly with compression of the proximal right iliac artery, and stopped in all nine volunteers by 120 pounds of pressure. For all nine volunteers, up to 80 pounds of pressure over the distal iliac artery failed to decrease CFA flow velocity, and no subject was able to tolerate more weight at that location. CONCLUSION: Flow to the CFA can be stopped completely with pressure over the distal AA or proximal iliac artery in catastrophic wounds. Compression over the proximal iliac artery worked best, but a first responder still may need to apply upward of 120 pounds of pressure to stop exsanguination.

Detection of metallic ocular foreign bodies with handheld sonography in a porcine model.

OBJECTIVE: Eye conditions are common in emergency departments. Intraocular foreign bodies (IOFBs) are a frequent concern. Orbital computed tomography (CT) is traditionally used for evaluation. We sought to evaluate bedside ocular sonography for detecting metallic IOFBs. METHODS: A pig model was chosen. A micrometer was used to create 3 precise metallic fragments: 0.012 x 0.012 x 0.012, 0.025 x 0.025 x 0.012, and 0.05 x 0.05 x 0.012 in. Individual eyes were randomized to the presence or absence of a foreign body. Randomization was also used to determine the specific size of any given IOFB. A standard 18-gauge spinal needle was used to puncture the sclera and introduce the IOFB into the vitreous. Each eye was then evaluated by 2 sonologists for the presence or absence of an IOFB. RESULTS: A total of 28 eyes were used; 12 (43%) were randomized to no IOFB and 16 (57%) to the presence of an IOFB. Of the 16 eyes that received IOFBs, 8 (50%) were 0.012 x 0.012 x 0.012 in; 5 (31%) were 0.025 x 0.025 x 0.012 in; and 3 (19%) were 0.05 x 0.05 x 0.012 in. Sensitivity was 87.5% and specificity 95.8%. Positive predictive value (PPV) and negative predictive value (NPV) were 96.5% and 85.2%, respectively. CONCLUSIONS: Bedside sonography may identify the presence of metallic IOFBs. The PPV allows a high degree of certainty that an IOFB is actually present if seen and may negate the need for uninfused orbital CT. The NPV was 85.2%. Given the potential grave consequences of a missed IOFB, sonography cannot be used as the definitive test to rule out the presence of a metallic IOFB. In the presence of negative findings, further imaging is warranted.

Intraoperative imprint cytology for evaluation of sentinel lymph nodes from visceral malignancies.

Although originally described for breast cancer and melanoma, sentinel lymph node (SLN) mapping techniques are being investigated in the treatment of visceral malignancies. There is no literature evaluating intraoperative analysis of SLNs from visceral sites. We evaluated the utility of touch preparation intraoperative imprint cytology (IIC) in evaluating SLNs harvested in the setting of visceral malignancy. SLN mapping procedures involving 50 cases of visceral malignancy (37 colon, 12 gastric, and 1 small bowel), from February 1999 through August 2001, were studied. In each case, subserosal injections of isosulfan blue were used to identify the SLN. The SLNs were then sent fresh to the pathology laboratory for evaluation by IIC. A standard lymphadenectomy was performed in all cases. Postoperatively, the SLNs were evaluated by means of using hematoxylin and eosin staining. If these stains were normal, immunohistochemical analyses using carcinoembryonic antigen and cytokeratin were subsequently performed. SLNs were successfully identified in 46 cases (92%), and a total of 95 SLNs were harvested. The average number of SLNs was 1.9 with a range of one to six. More SLNs were found with gastric than with colonic lesions (2.8 vs. 1.8; P=.017). Evaluable IIC in 41 cases revealed metastatic disease in 10 SLNs, representing seven patients. Of the 34 patients with normal IIC, five were found to have positive SLNs on hematoxylin and eosin staining. An additional three patients were found to have positive SLNs only on immunohistochemical analysis. The overall sensitivity and specificity of IIC was 64% and 100%, respectively. This resulted in a positive predictive value of 100% and a negative predictive value of 86%. The use of IIC to evaluate SLNs from visceral malignancies is clearly feasible. When the IIC of the SLN is positive, the surgeon may feel confident that disease is actually present in the SLN. If there is a negative result, the technique may miss disease that is present on subsequent permanent sections. We do not recommend routine use of IIC; however, it may be of use in clinical trials.

Intraoperative analysis of sentinel lymph nodes by imprint cytology for cancer of the breast.

BACKGROUND: The utilization of lymphatic mapping techniques for breast carcinoma has made intraoperative evaluation of sentinel lymph nodes (SLN) attractive, because axillary lymph node dissection can be performed during the initial surgery if the SLN is positive. The optimal technique for rapid SLN assessment has not been determined. Both frozen sectioning and imprint cytology are used for rapid intraoperative SLN evaluation. METHODS: A retrospective review of the intraoperative imprint cytology results of 133 SLN mapping procedures from 132 breast carcinoma patients was performed. SLN were evaluated intraoperatively by bisecting the lymph node and making imprints of each cut surface. Imprints were stained with hematoxylin and eosin (H&E) and Diff-Quik. Permanent sections were evaluated with up to four H&E stained levels and cytokeratin immunohistochemistry. Imprint cytology results were compared with final histologic results. RESULTS: Sensitivity and specificity of imprint cytology were 56% and 100%, respectively, producing a 100% positive predictive value and 88% negative predictive value. Imprint cytology was significantly more sensitive for macrometastasis than micrometastasis 87% versus 22% (P = 0.00007). Of 13 total false negatives, 11 were found to be due to sampling error and 2 due to errors in intraoperative interpretation. Both intraoperative interpretation errors involved a diagnosis of lobular breast carcinoma. CONCLUSIONS: The sensitivity and specificity of imprint cytology are similar to that of frozen section evaluation. Imprint cytology is therefore a viable alternative to frozen sectioning when intraoperative evaluation is required. If SLN micrometastasis is used to determine the need for further lymphadenectomy, more sensitive intraoperative methods will be needed to avoid a second operation.