Laparoscopic partial pancreatectomy of the left limb using a harmonic scalpel in nine cats.

OBJECTIVE: To describe a laparoscopic technique and outcome for partial pancreatectomy in cats. STUDY DESIGN: Prospective cohort study. ANIMALS: Nine cats. METHODS: Laparoscopic pancreatectomy was performed using a single incision laparoscopic surgery port and an additional 5.5 mm port. The left pancreatic limb was dissected, sealed and divided at the level of the splenic vein insertion to the portal vein using a harmonic device. Surgical time and complications were recorded. The weight and length of the resected pancreatic limb was recorded. Pre- and postoperative trypsin-like immunoreactivity (TLI), pancreatic lipase immunoreactivity (PLI), and hemoglobin A1C were documented. RESULTS: Laparoscopic partial pancreatectomy was performed successfully in all cats. One grade 1 intraoperative complication occurred (1/9; 11%) resulting in minor hemorrhage from a caudal splenic vein branch. A grade 2 postoperative complication occurred within 3 days after surgery in one cat (1/9; 11%), involving localized, sterile peritonitis in the region of the pancreatic angle. Signs resolved with conservative management. No cats exhibited signs of pancreatitis postoperatively. Long-term, mean TLI decreased by 37% ± 38% (p = .03) following partial pancreatectomy, while PLI and A1C were unchanged. All cats were alive and clinically well at last follow-up 250 to 446 days following surgery. CONCLUSIONS: Laparoscopic partial pancreatectomy using a harmonic device is effective in cats, and offers a minimally-invasive alternative to open surgical pancreatectomy techniques. Laparoscopic pancreatectomy of the left limb results in adequate exocrine and endocrine function in the long-term.

Radiographic and ultrasonographic appearance of a jejunal torsion-volvulus in a dog.

A 1.5-year-old male neutered, 5 kg, Dachshund was referred for anorexia and vomiting for several days' duration. Radiographs revealed concern for a small intestinal obstruction. Ultrasonography revealed a severely distended segment of jejunum containing echogenic fluid that abruptly narrowed, twisted, and transitioned into normal jejunum, along with the presence of a distinct "whirl sign" that resulted from the intestinal segments twisting around themselves. This, in addition to the absence of flow on power Doppler interrogation, was compatible with a focal jejunal torsion-volvulus. The torsion-volvulus was surgically confirmed, a resection and anastomosis was performed, and the dog recovered uneventfully.

Assessment of Burnout, Professional Fulfillment, and Strategies for Improvement in Veterinary Faculty at a Large Academic Department.

Retention and recruitment of clinical faculty is crucial for the success of quality veterinary education. Clinical faculty in busy teaching hospital environments have the potential to experience significant burnout, though few studies have focused on identifying stressors in this group. The objective of this study was to measure burnout and professional fulfillment in clinical faculty using a recently validated instrument, the Stanford Professional Fulfillment Index (PFI). The survey was distributed to faculty in July 2020, a time that coincided with the COVID-19 pandemic. The survey was completed by 80% (52/65) of survey recipients. Scores for Overall Burnout were significantly higher (p = .027) and Professional Fulfillment scores significantly lower (p < .001) for veterinary faculty when compared with a reference group of academic physicians; 61.7% (29/47) of the faculty met the criteria for burnout, and 20.4% (10/49) met the criteria for professional fulfillment. Overall Burnout and Professional Fulfillment scores were not affected by faculty rank or gender, although interpersonal disengagement was greater in faculty who had worked > 6 years at the institution (p = .032). Responses indicated that faculty valued their work and their patients but faced an excessive workload and lacked autonomy to make changes. Faculty proposed improving efficiency, increasing staffing, and distributing work to technical staff. The PFI is a brief, no-cost instrument validated for measuring burnout and fulfillment in health care workers that can be used to assess well-being among veterinary faculty. Involving faculty in suggesting interventions may yield a variety of creative and actionable options.

Cross-Sectional Assessment of the Emotional Intelligence of Fourth-Year Veterinary Students and Veterinary House Officers in a Teaching Hospital.

Emotional intelligence (EI) is the recognition and management of emotions. This skill set is important to work relationships and professional success. In this cross-sectional, observational study, we investigated EI scores of 4th-year veterinary students, interns, and residents in a teaching hospital, using a psychometric tool with professional population norms. Participants' EI scores were compared with professional norms and between the sample groups. Scores were examined on the basis of demographics and residency program type. Twenty-four 4th-year students and 43 interns and residents completed the survey. Total, composite, and subscale scores for all groups were lower than professional means. We noted no statistically significant differences in EI scores between training levels, but evaluation of effect sizes showed a medium negative effect of higher training levels on Self-Perception Composite, Self-Regard, Emotional Expression, Interpersonal Composite, Flexibility, and Optimism and a medium positive effect of higher training levels on Impulse Control. Medium effects for residency type were found for Stress Tolerance, Flexibility, and Stress Management, with higher scores for residencies with heavy inpatient loads. Medium effects for residency type were found on Flexibility scores, with higher scores for residents in disciplines with a perceived high stress level. We found that baseline EI scores of 4th-year veterinary students, interns, and residents at a teaching hospital were similar to, but uniformly lower than, those of other professionals and did not increase with training level. These results may be used to build on strengths and address weaknesses associated with EI of students and house officers at this institution.

Computed Tomography for the Diagnosis and Characterization of Dermoid Sinuses in Two Dogs.

A 6 mo old male castrated bloodhound-Rhodesian ridgeback mix (case 1) presented for a mass suspected to be a dermoid sinus in the thoracolumbar region, and a 2.5 yr old male castrated Rhodesian ridgeback (case 2) presented for a mass suspected to be a dorsal cervical dermoid sinus. Both dogs underwent single-phase contrast computed tomography (CT) to characterize the extent of the dermoid sinus prior to surgical excision. Soft tissue and bony abnormalities of the vertebral spine associated with the dermoid sinuses were confirmed in both dogs prior to surgery, demonstrating communication with the dura of the spinal cord. Surgical exploration and excision of the dermoid sinus was performed in each dog, including partial laminectomy. Both cases had resolution of the sinus and an uncomplicated recovery. These cases show that single-phase contrast CT was accurate in characterizing the extent of the dermoid sinus without adjunctive tests or more invasive diagnostics. Single-phase contrast CT should be considered as a preoperative method to characterize the extent of dermoid sinuses, avoiding the risks associated with myelography or fistulography and the expense of MRI. This is also the first report of a dermoid sinus in the thoracolumbar region and the first in a bloodhound and Rhodesian ridgeback mix.

Resolving Ethical Dilemmas in a Tertiary Care Veterinary Specialty Hospital: Adaptation of the Human Clinical Consultation Committee Model.

Technological advances in veterinary medicine have produced considerable progress in the diagnosis and treatment of numerous diseases in animals. At the same time, veterinarians, veterinary technicians, and owners of animals face increasingly complex situations that raise questions about goals of care and correct or reasonable courses of action. These dilemmas are frequently controversial and can generate conflicts between clients and health care providers. In many ways they resemble the ethical challenges confronted by human medicine and that spawned the creation of clinical ethics committees as a mechanism to analyze, discuss, and resolve disagreements. The staff of the North Carolina State University Veterinary Hospital, a specialty academic teaching institution, wanted to investigate whether similar success could be achieved in the tertiary care veterinary setting. We discuss the background and rationale for this method, as well as the approach that was taken to create a clinical ethics committee.

Duty hours restriction for our surgical trainees: An ethical obligation or a bad idea?

To ensure patient safety and protect the well-being of interns and residents, the Accreditation Council for Graduate Medical Education (ACGME) issued guidelines in 2003 limiting the working hours of physician trainees. Although many supported the goals of the ACGME, institutions struggled to restructure their programs and hire staff required by this unfunded mandate. Numerous studies have analyzed the effects of duty hours restrictions on patient outcomes and physician training over the past 15 years. Most agree that duty hours restrictions improved well-being of house officers, but these improvements came at the expense of continuity, and patient hand-offs led to medical errors. Effects on resident training are program specific, with duty hours restrictions having the most deleterious effects on surgical disciplines. Because veterinary specialists assume a similar role in providing 24-hour patient care, interns and residents face work-related stress as a result of extended working hours, on-call duty, and an increasingly complex caseload. The North Carolina State Veterinary Hospital is staffed by approximately 100 house officers representing almost every veterinary specialty group. We surveyed departing house officers regarding their quality of life and training experience. Sixty-six percent of interns and residents reported that they do not have time to take care of personal needs, and 57%-62% felt neutral or dissatisfied with their mental and physical well-being. Most trainees believed that decreased duty hours would improve learning, but 42% believed that decreased caseload would be detrimental to training. Veterinary educators must consider post-DVM veterinary training guidelines that maintain patient care with a good learning environment for interns and residents.

Hydrogen peroxide plasma sterilization of a waterproof, high-definition video camera case for intraoperative imaging in veterinary surgery.

OBJECTIVE: To evaluate the safety and usability of a wearable, waterproof high-definition camera/case for acquisition of surgical images by sterile personnel. STUDY DESIGN: An in vitro study to test the efficacy of biodecontamination of camera cases. Usability for intraoperative image acquisition was assessed in clinical procedures. METHODS: Two waterproof GoPro Hero4 Silver camera cases were inoculated by immersion in media containing Staphylococcus pseudointermedius or Escherichia coli at ≥5.50E+07 colony forming units/mL. Cases were biodecontaminated by manual washing and hydrogen peroxide plasma sterilization. Cultures were obtained by swab and by immersion in enrichment broth before and after each contamination/decontamination cycle (n = 4). The cameras were then applied by a surgeon in clinical procedures by using either a headband or handheld mode and were assessed for usability according to 5 user characteristics. RESULTS: Cultures of all poststerilization swabs were negative. One of 8 cultures was positive in enrichment broth, consistent with a low level of contamination in 1 sample. Usability of the camera was considered poor in headband mode, with limited battery life, inability to control camera functions, and lack of zoom function affecting image quality. Handheld operation of the camera by the primary surgeon improved usability, allowing close-up still and video intraoperative image acquisition. CONCLUSION: Vaporized hydrogen peroxide sterilization of this camera case was considered effective for biodecontamination. Handheld operation improved usability for intraoperative image acquisition. CLINICAL SIGNIFICANCE: Vaporized hydrogen peroxide sterilization and thorough manual washing of a waterproof camera may provide cost effective intraoperative image acquisition for documentation purposes.

Aldehyde dehydrogenase 1 a1 regulates energy metabolism in adipocytes from different species.

BACKGROUND: Survival and longevity of xenotransplants depend on immune function and ability to integrate energy metabolism between cells from different species. However, mechanisms for interspecies cross talk in energy metabolism are not well understood. White adipose tissue stores energy and is capable of mobilization and dissipation of energy as heat (thermogenesis) by adipocytes expressing uncoupling protein 1 (Ucp1). Both pathways are under the control of vitamin A metabolizing enzymes. Deficient retinoic acid production in aldehyde dehydrogenase 1 A1 (Aldh1a1) knockout adipocytes (KO) inhibits adipogenesis and increases thermogenesis. Here we test the role Aldh1a1 in regulation of lipid metabolism in xenocultures. METHODS: Murine wide-type (WT) and KO pre-adipocytes were encapsulated into a poly-L-lysine polymer that allows exchange of humoral factors <32kD via nanopores. Encapsulated murine adipocytes were co-incubated with primary differentiated canine adipocytes. Then, expression of adipogenic and thermogenic genes in differentiated canine adipocytes was detected by real-time polymerase chain reaction (PCR). The regulatory factors in WT and KO cells were identified by comparison of secretome using proteomics and in transcriptome by gene microarray. RESULTS: Co-culture of encapsulated mouse KO vs WT adipocytes increased expression of peroxisome proliferator-activated receptor gamma (Pparg), but reduced expression of its target genes fatty acid binding protein 4 (Fabp4), and adipose triglyceride lipase (Atgl) in canine adipocytes, suggesting inhibition of PPARγ activation. Co-culture with KO adipocytes also induced expression of Ucp1 in canine adipocytes compared to expression in WT adipocytes. Cumulatively, murine KO compared to WT adipocytes decreased lipid accumulation in canine adipocytes. Comparative proteomics revealed significantly higher levels of vitamin A carriers, retinol binding protein 4 (RBP4), and lipokalin 2 (LCN2) in KO vs WT adipocytes. CONCLUSIONS: Our data demonstrate the functional exchange of regulatory factors between adipocytes from different species for regulation of energy balance. RBP4 and LCN2 appear to be involved in the transport of retinoids for regulation of lipid accumulation and thermogenesis in xenocultures. While the rarity of thermogenic adipocytes in humans and dogs precludes their use for autologous transplantation, our study demonstrates that xenotransplantation of engineered cells could be a potential solution for the reduction in obesity in dogs and a strategy for translation to patients.

Radical Cystectomy and Cutaneous Ureterostomy in 4 Dogs with Trigonal Transitional Cell Carcinoma: Description of Technique and Case Series.

OBJECTIVE: To describe radical cystectomy followed by cutaneous ureterostomy as a treatment of invasive bladder neoplasia in dogs. STUDY DESIGN: Retrospective study. ANIMALS: Client-owned dogs with transitional cell carcinoma of the bladder trigone (n=4). METHODS: Perioperative complications and long-term outcomes of dogs that underwent cutaneous ureterostomy following radical cystectomy and lymphadenectomy for transitional cell carcinoma of the urinary bladder trigone were reviewed. Both ureters were transected and anastomosed to the ventral abdominal skin. Polyvinyl chloride catheters were placed in the ureteral stomas and maintained for 5 days. After catheter removal, dogs were managed with an absorbent diaper over the stomas. Long-term outcome and survival were documented by follow-up visits or phone contact. RESULTS: Median age at the time of surgery was 10.3 years (range, 8-12). Average procedural time was ∼4.7 hours (range, 3.8-6.1). Minor complications occurred in all dogs, including bleeding and edema of the ureterostomy site during the first 2-3 days after surgery. One dog developed urine scald that resolved with improved stoma care and hygiene. Median survival time after surgery was 278.6 days (range, 47-498). Distant metastases were documented in 2 dogs at 47 days (bone) and 369 days (lung) after surgery. CONCLUSION: Radical cystectomy with cutaneous ureterostomy is a viable salvage procedure for urinary diversion after cystectomy in dogs with invasive bladder neoplasia. Postoperative management and quality of life were considered acceptable by most owners. Future studies are warranted to evaluate survival time in a larger number of animals.

The Diabetic Dog as a Translational Model for Human Islet Transplantation.

The dog model has served as the primary method for early development of many diabetes therapies, including pancreatic islet transplantation techniques and immunosuppressive protocols. Recent trends towards the use of monoclonal antibody therapies for immunosuppression in human islet transplantation have led to the increasing use of primate models with induced diabetes. In addition to induced-disease models in large animals, scientists in many fields are considering the use of naturally-occurring disease models in client-owned pets. This article will review the applicability of naturally-occurring diabetes in dogs as a translational model for developing islet transplantation in the human diabetic patient.

Laparoscopic placement and urodynamic effects of an artificial urethral sphincter in cadaveric dogs.

OBJECTIVE: To describe a laparoscopic approach for placement of a percutaneously controlled artificial urethral sphincter (AUS) in female cadaver dogs and compare the change in urethral pressure and lumen diameter after filling the device. STUDY DESIGN: Experimental study. ANIMALS: Canine female cadavers (n = 10). METHODS: A laparoscopic technique was used to implant the AUS in 10 cadaver dogs. Maximum urethral closure pressure (MUCP), cystourethral leak point pressure (CLPP), and urethral luminal area were measured at 0, 25, 50, and 75% cuff inflation. Necropsy was performed after urethral pressure profilometry and cystoscopy data collection to assess for trauma caused by the procedure. RESULTS: Laparoscopic implantation was performed successfully in all 10 cadavers with no evidence of inadvertent trauma. Median MUCP at 0% AUS fill (48.9 cmH2 O) was significantly lower than 75% fill (243.5 cmH2 O). Median CLPP at 0% fill (5.0 cmH2 O) was significantly lower than 75% fill (23.2 cmH2 O). Significant differences were also found comparing urodynamic values 25 to 50%, 25 to 75%, and 50 to 75%. Cystoscopic evaluation revealed progressive decreases in urethral lumen area and significant differences between the urethral luminal area values as the AUS cuff was inflated. CONCLUSION: Laparoscopic placement of an AUS can be performed successfully in cadaver dogs, improved urethral pressure profile parameters, and visibly occluded the urethral lumen. Further studies of laparoscopic placement in clinical cases affected by urethral sphincter mechanism incompetence are warranted.

Suture-Free Ureterovesical Anastomosis Using a Microvascular Anastomosis System: Canine Cadaveric Study.

OBJECTIVE: To describe a suture-free ureterovesical anastomosis using a microvascular anastomotic system (MAS) and compare the surgical time and bursting pressure to a sutured ureterovesical anastomosis (SA) with and without an extravesical seromuscular tunnel (EVSMT). STUDY DESIGN: Randomized, unblocked design, ex vivo study. ANIMALS: Three canine cadavers. METHODS: For each cadaver, the ureters were sectioned into 3 equal lengths. The 6 sections were randomly assigned to receive either the MAS or end-side SA. The first cadaver (3 MAS, 3 SA) was used to refine the technique, and the remaining 2 cadavers were used for evaluation. Surgical time and bursting pressure of the anastomosis were compared between MAS and SA (n = 6 per technique). After bursting pressure testing of each anastomosis, an SMT was created over the anastomoses. Bursting pressures were again recorded and compared across techniques. RESULTS: The surgery time was significantly shorter for MAS (median 5.4 minutes) than SA (median 15.8 minutes; P = .002). The bursting pressure was significantly higher for MAS (median 189.5 cmH2 O) than SA (median 64 cmH2 O; P = .002). The bursting pressure for MAS-EVSMT (median 398.5 cmH2 O) was not significantly different from the SA-EVSMT (median 321 cmH2 O, P = .567); however, the creation of an SMT significantly increased the bursting pressure for both techniques (P = .028, respectively). CONCLUSION: This study demonstrated the feasibility of a suture-free ureterovesical anastomosis in the canine cadaver using a commercially available MAS. The MAS anastomosis was faster and resulted in higher bursting pressures than SA. The creation of an SMT improved the bursting resistance of both techniques but there was no difference between the techniques covered by an EVSMT.

Suture-free technique for canine ureteral resection-anastomosis using a microvascular anastomotic system: a cadaveric study.

OBJECTIVE: To describe a suture-free technique for canine ureteral resection-anastomosis using a microvascular anastomotic system (MAS) and to compare surgical time and burst pressure of hand-sewn (HS) ureteral end-to-end anastomosis with the MAS technique. STUDY DESIGN: Experimental ex vivo study. ANIMALS: Canine cadavers (n = 8). METHODS: For each cadaver, 1 ureter was randomly assigned to undergo HS anastomosis and the contralateral ureter had MAS anastomosis. The first 3 cadavers (6 ureters) were used to refine the MAS technique. In the other 5 dogs, surgical time and ureteral burst pressure were compared between groups (n = 5 ureters/group). RESULTS: Preliminary procedures showed that selective impaling of the mucosa and submucosa (without muscularis and adventitia) is necessary to allow complete mechanical interlock of the anastomotic rings for the MAS technique. Median anastomotic time was significantly shorter for MAS (7.6 min) than HS (16.6 min; p = .029) and burst pressure higher for MAS (393 cm H2 O) than HS (180 cm H2 O; p = .012). CONCLUSION: This study demonstrated the feasibility of a suture-free technique of canine ureteral resection-anastomosis using a commercially available MAS. The MAS anastomosis was faster and had higher burst strength compared with the HS anastomosis.

Pancreatic islet transplantation: from dogs to humans and back again.

Pancreatic islet transplantation is a cell-based therapy that provides a potential cure for type 1 diabetes mellitus. After the introduction of an automated method for islet isolation and steroid-free immunosuppressive protocols, reversal of diabetes by islet transplantation is now performed at major human medical centers around the world. Despite extensive use of animal models in islet transplantation research, practical concerns have slowed the introduction of the technique into clinical veterinary practice and only a small number of studies have reported results of transplantation in dogs with spontaneously occurring diabetes mellitus; however, recent advances in islet isolation and encapsulation may make it possible to perform islet transplantation without immunosuppression in companion animals. This review summarizes experimental and clinical studies of pancreatic islet transplantation in dogs, including future directions for cell therapy in animals with naturally occurring disease.

Isolation of feline islets of Langerhans by selective osmotic shock produces glucose responsive islets.

Introduction: Pancreatic islet isolation is essential for studying islet physiology, pathology, and transplantation, and feline islets could be an important model for human type II diabetes mellitus (T2D). Traditional isolation methods utilizing collagenases inflict damage and, in cats, may contribute to the difficulty in generating functional islets, as demonstrated by glucose-stimulated insulin secretion (GSIS). GLUT2 expression in ß cells may allow for adaptation to hyperosmolar glucose solutions while exocrine tissue is selectively disrupted. Methods: Here we developed a protocol for selective osmotic shock (SOS) for feline islet isolation and evaluated the effect of different hyperosmolar glucose concentrations (300 mmol/L and 600 mmol/L) and incubation times (20 min and 40 min) on purity, morphology, yield, and GSIS. Results: Across protocol treatments, islet yield was moderate and morphology excellent. The treatment of 600 mmol/L glucose solution with 20 min incubation resulted in the highest stimulation index by GSIS. Discussion: Glucose responsiveness was demonstrated, permitting future in vitro studies. This research opens avenues for understanding feline islet function and transplantation possibilities and enables an additional islet model for T2D.

Tunneling under the digastricus muscle increases salivary duct exposure and completeness of excision in mandibular and sublingual sialoadenectomy in dogs.

OBJECTIVE: To document the extent of rostral salivary duct and glandular tissue excision achieved through a conventional lateral approach before and after tunneling under the digastricus muscle. STUDY DESIGN: Experimental cadaveric study. ANIMALS: Dog cadavers (n = 8). METHODS: Bilateral mandibular and sublingual sialoadenectomy was performed in 8 cadavers using a conventional lateral approach and the point of proposed salivary duct transection was marked with Evans blue dye. Remaining salivary duct was then tunneled under the digastricus muscle and dissection continued rostrally. The most rostral point of the gland/duct complex was marked before transection of the salivary duct. Once removed, the distance between the 2 marks was measured and recorded. Completeness of glandular tissue excision was confirmed by dissection and gross examination. RESULTS: The tunneling technique improved rostral exposure and increased the median (IQR) length of salivary duct excision by 1.8 (0.35) cm. Residual polystomatic sublingual salivary tissue remained in all cadavers after simulated resection without tunneling under the digastricus muscle. After tunneling, complete removal of rostral salivary tissue was achieved in 13 of 15 procedures. CONCLUSIONS: Tunneling under the digastricus muscle increases the length of rostral salivary duct and glandular tissue that can be removed through a conventional lateral approach.

Outcome after placement of an artificial urethral sphincter in 27 dogs.

OBJECTIVE: To evaluate the safety and efficacy of an adjustable artificial urethral sphincter (AUS) in a population of dogs with acquired or congenital urinary incontinence. STUDY DESIGN: Case series. ANIMALS: Dogs (n = 27) with naturally occurring urinary incontinence. METHODS: Medical records (January 2009-July 2011) of dogs that had AUS implantation for treatment of urinary incontinence were reviewed and owners were interviewed by telephone to assess outcome. Continence was scored using a previously established analogue scale, with 1 representing constant leakage and 10 representing complete continence. RESULTS: Twenty-four female and 3 male dogs had AUS implantation. Causes of incontinence included urethral sphincter mechanism incompetence (n = 18), continued incontinence after ectopic ureter repair (6), and pelvic bladder (3). Medical therapy was unsuccessful in 25 dogs before AUS implantation. Surgery was performed without major complications in 25 dogs; 2 developed partial urethral obstruction after 5 and 9 months. Median (interquartile range) follow-up for the other 25 dogs was 12.5 (6-19) months. Continence scores were significantly improved (P < .0001) between the preoperative period (2 [1-4]) and last follow-up (9 [8-10]). Overall, 22 owners described themselves as very satisfied, 2 as satisfied, and 3 as unsatisfied. CONCLUSIONS: AUS implantation was successful in restoring continence in male and female dogs with both congenital and acquired urinary incontinence. Dogs that develop partial urethral obstruction may require AUS removal.

Assessment of the FreeStyle Libre 2 interstitial glucose monitor in hypo- and euglycemic cats.

BACKGROUND: Continuous glucose monitoring systems have been validated for eu- and hyperglycemic cats. The FreeStyle Libre 2 (FSL2) is sufficiently accurate in people during hypoglycemia to guide critical treatment decisions without confirmation of blood glucose concentration (BG). OBJECTIVES: Assess FSL2 accuracy in cats with hypoglycemia. ANIMALS: Nine healthy, purpose-bred cats. METHODS: Hyperinsulinemic-hypoglycemic clamps were performed by IV infusion of regular insulin (constant rate) and glucose (variable rate). Interstitial glucose concentration (IG), measured by FSL2, was compared to BG measured by AlphaTrak2. Data were analyzed for all paired measurements (n = 364) and separately during stable BG (≤1 mg/dL/min change over 10 minutes). Pearson's r test, Bland-Altman test, and Parkes Error Grid analysis respectively were used to determine correlation, bias, and clinical accuracy (P < .05 considered significant). RESULTS: Overall, BG and IG correlated strongly (r = 0.83, P < .0001) in stable glycemia and moderately at all rates of change (r = 0.69, P < .0001). Interstitial glucose concentration underestimated BG in euglycemia, but the BG-IG difference was progressively smaller as BG decreased (12.9 ± 12.2, 8.8 ± 11.2, -3.2 ± 7.4, and -7.8 ± 5.2 mg/dL in the ranges of 80-120 [n = 64], 60-79 [n = 29], 50-59 [n = 71], and 29-49 mg/dL [n = 53], respectively). CONCLUSIONS: Although IG underestimates BG throughout most of the hypo-euglycemic range, IG generally overestimates BG in marked hypoglycemia (<60 mg/dL). It is therefore imperative to evaluate FSL2 results in this critical range with caution.