The HemoCue®, a point of care B-hemoglobin photometer, measures hemoglobin concentrations accurately when mixedin vitro with canine plasma and three hemoglobin-based oxygen carriers (HBOC)

PURPOSE: Accuracy of measurement of low hemoglobin concentrations using the HemoCue, a B-hemoglobin photometer (HemoCue AB, Angelholm, Sweden) may exhibit significant variability. Infusion of hemoglobin-based oxygen carriers (HBOC) results in low concentrations of plasma hemoglobin. Our study assessed B-hemoglobin photometer measurement accuracy of three HBOC: (hemoglobin glutamer-200 (bovine; Oxyglobin, Biopure Corp., Cambridge, MA, USA); hemoglobin glutamer-250 (bovine; Hemopure, Biopure Corp, Cambridge, MA, USA), and hemoglobin-raffimer, (human; Hemolink, Hemosol, Inc., Toronto, Ontario, Canada). METHODS: In the laboratory, 45 split canine plasma samples were mixed with hemoglobin glutamer-200 (8.13, 16.25, 32.5 g x L(-1) concentrations), 45 samples were mixed with hemoglobin glutamer-250 (8.13, 16.25, 32.5 g x L(-1) concentrations), 45 with hemoglobin-raffimer (12.5, 25.0, 50.0 g x L(-1) concentrations), and measured. Plasma samples without HBOC served as control. Hemoglobin concentration was determined by a laboratory analyzer (Coulter Corporation, Hiafeah, FL, USA) and B-hemoglobin photometer (HemoCue, Angelholm, Sweden). Two independent technicians performed blinded sample measurements and randomly tested each sample five times. Results were analyzed according to Bland and Altman analysis. RESULTS: B-hemoglobin photometer demonstrated high repeatability for all three HBOCs. Repeatability coefficients were 0.37 g x L(-1) and 0.48 g x L(-1) for hemoglobin glutamer-200, 0.39 g x L(-1) and 0.4 g x L(-1) for hemoglobin glutamer-250 and 1.07 g x L(-1) and 0.85 g x L(-1) for hemoglobin-raffimer. An acceptable agreement was found between the B-hemoglobin photometer and the laboratory analyzer for all three HBOCs tested. CONCLUSION: The B-hemoglobin photometer accurately determined the concentration of three HBOC solutions dissolved in canine plasma.     

Reproducibility of ultrasound scan in the assessment of volume flow in the veins of the lower extremities

PURPOSE: The purpose of this study was the identification of the optimal settings of ultrasound scan flow measurement in the veins and the determination of whether the standardization of these settings can provide acceptable reproducibility of the venous flow measurements in individual segments of the lower extremity veins. METHODS: The venous cross-sectional area, the time average mean velocity, and the venous volume flow of 25 healthy volunteers were examined with duplex ultrasound scanning. Reproducibility was examined with different measurement settings. Doppler scan sample volume size, ultrasound scan beam incident angle, and time interval of measurement were varied across a spectrum for arrival at the setting for highest reproducibility of the flow volume measurements. Test-retest reproducibility of venous flow volume measurements then was investigated with optimized settings. RESULTS: The highest repeatability of volume flow measurements was achieved when the full lumen of the vein was insonated (coefficient of repeatability [CR] = 1.88 cm/s), the ultrasound scan beam incident angle was equal to 60 degrees (CR = 1.56 cm/s), and the measurement time was more than 40 seconds (CR = 1.64 cm/s). The mean values of volume flow were 360 mL/min in the common femoral vein, 147 mL/min in the superficial femoral vein, 86 mL/min in the profunda femoral vein, and 38 mL/min in the greater saphenous vein. Test-retest repeatability coefficients were 96.9 mL/min for the common femoral vein, 70.2 mL/min for the superficial femoral vein, 40.8 mL/min for the profunda femoral vein, and 16.8 mL/min for the greater saphenous vein. CONCLUSION: The reproducibility of ultrasound scan measurements of volume flow in veins is optimized with the use of sampling volumes that cover the entire venous lumen, with an incident angle of 60 degrees and measuring for 40-second intervals or longer. With these defined variables, volumetric measurements are sufficiently repeatable. the values of flow volume measured with duplex ultrasound scanning were comparable to those with thermodilution techniques that were reported previously.     

Postoperative nausea and vomiting: comparison of the effect of postoperative meperidine or morphine in gynecologic surgery patients

STUDY OBJECTIVE: To evaluate the incidence and severity of postoperative nausea and vomiting in women receiving postoperative intravenous morphine or meperidine following gynecologic surgery. DESIGN: Prospective, double-blind, randomized study. SETTING: Tertiary-care academic medical center. PATIENTS: 200 ASA physical status I, II, and III patients scheduled for elective gynecologic surgery. INTERVENTIONS: Patients received either postoperative IV morphine (n = 100) or meperidine (n = 100) following gynecologic surgery. MEASUREMENTS: We compared pain scores, sedation scores, nausea scores, well-being scores, vomiting rate, and patient satisfaction in both groups 15, 30, 60, and 120 minutes after arrival in the postoperative anesthesia care unit. MAIN RESULTS : The vomiting rate was 8/100 versus 7/100 (at 15 min), 4/100 versus 26/100 (at 30 min) (p < 0.05), 3/100 versus 23/100 (at 60 min) (p < 0.05), and 0/100 versus 0/100 (at 120 min) in the morphine or meperidine groups, respectively. The pain and sedation scores were similar in both groups. No major complications were noted in either group. CONCLUSION: Our study demonstrates an advantage of the use of morphine rather than meperidine for pain control in the immediate postoperative period following gynecologic surgery.     

Bisphosphonate-induced Osteonecrosis of the Jaws: Review, Clinical Implications and Case Report

The introduction of bisphosphonates has increased in the last decade following their indication for metastatic bone diseases, osteoporosis, hypercalcaemia of malignancy and Paget’s disease. Although bisphosphonates have been used clinically for more than three decades there have been no documented long-term complications of their effects on the jaws until recently, where there is now growing evidence of the influence of bisphosphonates on osteonecrosis of the jaws. The aim of this paper is to report a case of this newly described complication, to review this phenomenon, including the clinical implications and to reiterate current clinical guidelines for management of patients in which bisphosphonate therapy is indicated. To the best of our knowledge this is the first reported case of bisphosphonate-induced necrosis of the jaw in South Africa.     

Retrolisthesis and lumbar disc herniation: a preoperative assessment of patient function.

BACKGROUND CONTEXT: Retrolisthesis is relatively rare but when present has been associated with increased back pain and impaired back function. Neither the prevalence of this condition in individuals with lumbar disc herniations nor its possible relation to preoperative back pain and dysfunction has been well studied. PURPOSE: The purposes of this study were as follows: (1) to determine the prevalence of retrolisthesis (alone or in combination with other degenerative conditions) in individuals with confirmed L5-S1 disc herniation who later underwent lumbar discectomy; (2) to determine if there is any association between retrolisthesis and degenerative changes within the same vertebral motion segment; and (3) to determine the relation between retrolisthesis (alone or in combination with other degenerative conditions) and preoperative low back pain, physical function, and quality of life. STUDY DESIGN/SETTING: Cross-sectional study. PATIENT SAMPLE: A total of 125 individuals were identified for incorporation into this study. All patients had confirmed L5-S1 disc herniation on magnetic resonance imaging (MRI) and later underwent L5-S1 discectomy. All patients were enrolled in the Spine Patient Outcomes Research Trial (SPORT) study; data were obtained from the multi-institutional database comprised of SPORT patients from across the United States. OUTCOME MEASURES: Retrolisthesis, degenerative change on MRI, and Modic changes. METHODS: MRI scans of the lumbar spine were assessed at spinal level L5-S1 for all 125 patients. Retrolisthesis was defined as posterior subluxation of 8% or more. Disc degeneration was defined as any loss of disc signal on T2 imaging. Modic changes were graded 1 to 3 and collectively classified as vertebral endplate degenerative changes. The presence of facet arthropathy and ligamentum flavum hypertrophy was classified jointly as posterior degenerative changes. RESULTS: The overall incidence of retrolisthesis at L5-S1 in our study was 23.2%. Retrolisthesis combined with posterior degenerative changes, degenerative disc disease, or vertebral endplate changes had incidences of 4.8%, 16%, and 4.8% respectively. The prevalence of retrolisthesis did not vary by sex, age, race, smoking status, or education level when compared with individuals with normal sagittal alignment. However, individuals with retrolisthesis were more likely to be receiving workers' compensation than those without retrolisthesis. Increased age was found to be associated with individuals having vertebral endplate degenerative changes (both alone and in conjunction with retrolisthesis) and degenerative disc disease. Individuals who had retrolisthesis with concomitant vertebral endplate degenerative changes were more often smokers and had no insurance. The presence of retrolisthesis was not associated with an increased incidence of having degenerative disc disease, posterior degenerative changes, or vertebral endplate changes. No statistical significance was found between the presence of retrolisthesis on the degree of patient preoperative low back pain and physical function. Patients with degenerative disc disease were found to have increased leg pain compared with those patients without degenerative disc changes. CONCLUSIONS: We found no significant relationship between retrolisthesis in patients with L5-S1 disc herniation and worse baseline pain or function. It is possible that the contribution of pain or dysfunction related to retrolisthesis was far overshadowed by the presence of symptoms caused by the concomitant disc herniation. It remains to be seen whether retrolisthesis will affect outcome after discectomy in these patients.     

The effects of positive end-expiratory pressure during active compression decompression cardiopulmonary resuscitation with the inspiratory threshold valve

The use of an inspiratory impedance threshold valve (ITV) during active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) improves perfusion pressures, and vital organ blood flow. We evaluated the effects of positive end-expiratory pressure (PEEP) on gas exchange, and coronary perfusion pressure gradients during ACD + ITV CPR in a porcine cardiac arrest model. All animals received pure oxygen intermittent positive pressure ventilation (IPPV) at a 5:1 compression-ventilation ratio during ACD + ITV CPR. After 8 min, pigs were randomized to further IPPV alone (n = 8), or IPPV with increasing levels of PEEP (n = 8) of 2.5, 5.0, 7.5, and 10 cm H(2)O for 4 consecutive min each, respectively. Mean +/- SEM arterial oxygen partial pressure decreased in the IPPV group from 150 +/- 30 at baseline after 8 min of CPR to 110 +/- 25 torr at 24 min, but increased in the PEEP group from 115 +/- 15 to 170 +/- 25 torr with increasing levels of PEEP (P <0.02 for comparisons within groups). Mean +/- SEM diastolic aortic minus diastolic left ventricular pressure gradient was significantly (P < 0.001) higher after the administration of PEEP (24 +/- 0 vs 17 +/- 1 mm Hg with 5 cm H(2)O of PEEP, and 26 +/- 0 vs 17 +/- 1 mm Hg with 10 cm H(2)O of PEEP), whereas the diastolic aortic minus right atrial pressure gradient (coronary perfusion pressure) was comparable between groups. Furthermore, systolic aortic pressures were significantly (P < 0.05) higher with 10 cm H(2)O of PEEP when compared with IPPV alone (68 +/- 0 vs 59 +/- 2 mm Hg). In conclusion, when CPR was performed with devices designed to improve venous return to the chest, increasing PEEP levels improved oxygenation. Moreover, PEEP significantly increased the diastolic aortic minus left ventricular gradient and did not affect the decompression phase aortic minus right atrial pressure gradient. These data suggest that PEEP reduces alveolar collapse during ACD + ITV CPR, thus leading to an increase in indirect myocardial compression. IMPLICATIONS: Inspiratory impedance during active compression-decompression cardiopulmonary resuscitation improves perfusion pressures, and vital organ blood flow during cardiac arrest. Increasing levels of positive end-expiratory pressure during performance of active compression-decompression cardiopulmonary resuscitation with an inspiratory impedance valve improves oxygenation, and increases the diastolic aortic-left ventricular pressure gradient and systolic arterial blood pressure.     

A novel approach to measuring circulating blood volume: the use of a hemoglobin-based oxygen carrier in a rabbit model

Hemoglobin-based oxygen carriers (HBOC) may be ideal for monitoring circulating plasma volume (CV-P) and circulating blood volume (CV-B). We used an HBOC (Hemoglobin glutamer-200 [bovine], Oxyglobin; Biopure, Cambridge, MA) as an indicator for relative CV-B in the rabbit model. Accuracy of the technique was determined by comparison with the Evans blue dye (EBD) dilution technique in 19 anesthetized female New Zealand rabbits weighing 2.0 to 10.6 kg. The measurements were performed at baseline, after hemorrhage (1/3 of CV-B), normovolemic hemodilution (replacement of 1/3 CV-B by Hextend; Abbot Laboratories, North Chicago, IL), and hypervolemic hemodilution (additional infusion of Hextend(R) in a volume equal to 1/3 of CV-B). Hemoglobin concentration was measured by using a HemoCue photometer (HemoCue AB, Angelholm, Sweden). EBD concentration was analyzed by using linear regression to estimate Time 0 concentration; Time 0 was defined as EBD injection time. The difference between CV-P values determined by EBD and HBOC dilution was independent from the magnitude of the CV-P value. The relative bias was 1.29 mL, and the precision (one SD) was 2.82 mL. The difference did not reach statistical significance. IMPLICATIONS: Circulating plasma and blood volumes can be accurately estimated by plasma hemoglobin concentration measurements by using hemoglobin-based oxygen carrier infusion.     

Elevated carcinoembryonic antigen levels and biliary tract obstruction.

Circulating carcinoembryonic antigen (CEA) levels and their relation to liver function test values were studied in 29 jaundiced patients with benign extrahepatic biliary tract obstruction and inflammation. During the obstructive and inflammatory phase, 15 (52%) of the patients had CEA levels greater than 2.5 ng/ml. Elevated CEA levels were associated more frequently with common bile duct stones (and cholangitis) than with gallbladder stones (and cholecystitis) alone, although this difference was not statistically significant. The former often had values greater than 5.0 ng/ml. The highest values were found in two patients with liver abscesses. T'HE CEA levels returned to normal following relief of obstruction in seven of ten patients and increased in two patients who had progressive inflammation. Serum alkaline phosphatase and bilirubin levels were significantly higher in the patients with elevated CEA levels (p smaller than .05). Serum alkaline phosphatase levels showed a significant positive correlation with CEA levels (p smaller than .02). Patients with obstructive jaundice and elevated CEA levels do not necessarily have cancer.     

Giant-cell tumour in the cervical spine: a case report

A forty-six-year-old man presented with a two-month history of increasing neck pain of insidious onset. He received treatment from his familty doctor and chiropractor consisting of analgesics and manipulation respectively, both of which did not offer relief. The patient presented to University Hospital where plain radiographs and CT showed a pathological fracture of the C4 vertebral body. A neoplasm was suspected and surgical excision revealed a giant-cell tumour of bone. This type of neoplasm is rare in the spine and difficult to manage in this site. This case highlights some of the problems encountered in the treatment of giant-cell tumour of the spine.