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Biomedical subjects

Andrew Y C Wong

Publications and source records attributed to Andrew Y C Wong.

4 recordsLinked to original sources

A comparison of pain on intravenous injection between two preparations of propofol.

Propofol is frequently used for sedation, induction, and maintenance of anesthesia. It is, however, associated with pain on injection. Propofol-Lipuro has an oil phase that allows a larger proportion of propofol to be dissolved in it and, thereby, apparently reduces pain. However, studies investigating this have had methodological limitations. We devised a randomized, double-blind, crossover study comparing pain on injection between two preparations of propofol, Diprivan and Propofol-Lipuro, in subanesthetic doses. Sixty healthy patients received the drugs in random order via the same injection site separated by 10 min and a 0.9% saline flush. Pain was assessed using a verbal rating score (VRS) during and at 1-min time points after injection. Differences in VRS between the two propofol preparations at different time points in each patient were analyzed. In patients who were given Diprivan first followed by Propofol-Lipuro (group D-P), pain was significantly reduced with Propofol-Lipuro compared with Diprivan during initial injection (median difference in VRS = 2 [interquartile range 0-2], P = 0.002) and at 1 min (3 [0-4], P < 0.001). In patients who were given Propofol-Lipuro first followed by Diprivan (group P-D), no significant differences in VRS were shown. Propofol-Lipuro is associated with reduced injection pain compared with Diprivan and also seems to attenuate subsequent injection pain of Diprivan when administered first. The mechanism is unknown, but may be related to a reduction in the concentration of propofol in the aqueous phase.

Adult↗

Anesthetic management of Cesarean delivery in a patient with hypoplastic anemia and severe pre-eclampsia.

PURPOSE: To describe the anesthetic management of Cesarean delivery in a patient with hypoplastic anemia and severe pre-eclampsia. CLINICAL FEATURES: A 28-yr-old parturient with a history of thrombocytopenia was admitted with signs of pre-eclampsia (blood pressure of 140/90 mmHg, heavy proteinuria and moderate bilateral ankle edema) at 25 weeks of gestation. Laboratory studies revealed pancy-topenia (hemoglobin 6.4 g.dL(-1), white cell count 3.43 x 10(9).L(-1), platelet count 20 x 10(9).L(-1)) and bone marrow biopsy showed hypoplastic anemia. As pre-eclampsia worsened, a Cesarean delivery was performed at 27 weeks with prophylactic platelet transfusion and meticulous blood pressure control. The procedure was uneventful, conducted under general anesthesia with an estimated blood loss of around 600 mL and a live female baby was delivered. Postoperatively her blood pressure and neurological symptoms improved but thrombocytopenia remained at discharge. CONCLUSIONS: Hypoplastic anemia is rare in pregnancy but it poses an increased risk for both mother and fetus. The mother is at risk of life-threatening episodes of bleeding and infection and a multidisciplinary team approach (obstetrician, anesthesiologist, hematologist and pediatrician) is essential. An accurate assessment of the hematological condition should be made and abnormalities corrected before surgery. Regional anesthesia may not be possible in this circumstance.

Adult↗

Desmopressin does not decrease blood loss and transfusion requirements in patients undergoing hepatectomy.

PURPOSE: To determine the effects of desmopressin on coagulation and blood loss in patients undergoing elective partial hepatectomy. METHODS: A randomized, controlled and double-blind study on 59 patients who received either 0.3 micro g x kg(-1) of desmopressin or an equal volume of normal saline (control) infused intravenously over 20 min after induction of general anesthesia. RESULTS: There was an increase in plasma levels of factors VIII and von Willebrand after the infusion of study drug in both groups (P < 0.001). The activated partial thromboplastin time was shortened in Group D whereas prothrombin time was prolonged in Group C; (P = 0.02). A large range of intraoperative blood loss (400-7128 mL) was observed, with no significant differences between groups. There were no changes in plasma electrolyte levels or osmolality. Transfusion requirements were similar in both groups. CONCLUSION: Desmopressin did not reduce intraoperative blood loss or transfusion requirements during hepatectomy despite raising clotting factor levels and improving tests of hemostasis.

Blood Coagulation Tests↗