Kokila Thenuwara

Effect of Mannitol and Furosemide on Plasma Osmolality and Brain Water

Background Mannitol and furosemide are used to reduce increased intracranial pressure (ICP) and to reduce brain bulk during neurosurgery. One mechanism by which these changes might occur is via a reduction in brain water content. Although mannitol and furosemide are commonly used in combination, there has been no formal evaluation of the interactive effects of these two drugs on brain water. The effect of mannitol and furosemide alone and in combination on water content of normal rat brain was examined. Methods The lungs of rats anesthetized with halothane were mechanically ventilated to maintain normal physiologic parameters. After baseline measurement of plasma osmolality, mannitol (1, 4, or 8 g/kg), furosemide (2, 4, or 8 mg/kg), or a combination of furosemide (8 mg/kg) and mannitol (1, 4, or 8 g/kg) was administered intravenously over approximately 15 min. One hour later, plasma osmolality was measured, the animals were killed, and brain water content was determined by wet and dry weight measurements. Results Mannitol produced a dose-dependent increase in plasma osmolality and reduction of brain water content. There was a linear relation between plasma osmolality and brain water content. Furosemide alone did not affect plasma osmolality or brain water at any dose. The combination of furosemide with mannitol resulted in a greater increase in plasma osmolality than seen with mannitol alone and a greater decrease in brain water at 4 and 8 g/kg of mannitol. Conclusions The doses of mannitol and furosemide utilized were much larger than clinically applicable doses and were selected to maximize the ability to detect effect on brain water. The combination of mannitol and furosemide resulted in greater reduction of brain water content than did mannitol alone. Furosemide enhanced the effect of mannitol on plasma osmolality, resulting in a greater reduction of brain water content. Potential interaction (if any) of smaller, clinically used doses of mannitol and furosemide cannot be surmised from the current study.

Mean operating room times differ by 50% among hospitals in different countries for laparoscopic cholecystectomy and lung lobectomy

We explored whether there were large differences in operating room (OR) times for two common procedures performed by multiple surgeons at each of several hospitals thousands of miles apart. Mean OR time, “wheels in” to “wheels out,” for ten consecutive cases of each of laparoscopic cholecystectomy and lung lobectomy were obtained for each of ten hospitals in eight countries from their OR logs. After log transformation, the OR times were analyzed by analysis of variance. Mean OR times differed significantly among hospitals (P = 0.006, laparoscopic cholecystectomy; P < 0.001, lung lobectomy). The second longest average OR time was 50% longer than the second shortest average OR time for both laparoscopic cholecystectomy and lung lobectomy. Differences in OR times among the hospitals we studied were large enough to affect the productivity of OR nurses and anesthesia providers. Thus, international benchmarking studies to understand differences in OR times worldwide may be beneficial.

The effect of a single intraoperative dose of intravenous dexamethasone 8 mg on post-cesarean delivery analgesia: a randomized controlled trial

BACKGROUND A single perioperative dose of dexamethasone has been shown to improve postoperative analgesia and reduce opioid consumption. However, this analgesic and opioid sparing effect has not been well assessed as part of a multimodal analgesic regimen in women post-cesarean delivery. METHODS Healthy women having cesarean delivery under spinal anesthesia were randomly assigned to receive intravenous dexamethasone 8 mg or placebo after delivery and clamping of the umbilical cord. The primary outcome variable was total opioid consumption in the 24 hours following cesarean delivery. We hypothesized that a single dose of intravenous dexamethasone, administered as part of a multimodal analgesia regimen after spinal anesthesia for cesarean delivery, would significantly reduce postoperative opioid consumption. RESULTS Fifty-two women were enrolled and randomized to two groups of 26 patients. The median (IQR) opioid consumption in the first 24 hours after cesarean delivery was 12 mg (5-20 mg) in the dexamethasone group compared to 15 mg (5-22 mg) in the placebo group. The median difference in opioid consumption at 24 hours (95% CI) was -3 mg (-12.2 to 5.7) and was not significantly different between groups (P=0.32). CONCLUSIONS The addition of intravenous dexamethasone 8 mg to a multimodal postoperative analgesic regimen that included intrathecal morphine, in women who had a cesarean delivery under spinal anesthesia, did not reduce 24 hour postoperative opioid consumption.

Use of hyperbaric oxygen therapy and PEGylated carboxyhemoglobin bovine in a Jehovah’s Witness with life-threatening anemia following postpartum hemorrhage

We present a case of a Jehovahs Witness patient who refused blood products, with the exception of albumin and clotting factors, and underwent cesarean section under spinal anesthesia complicated by postpartum hemorrhage. She was fluid resuscitated and treated with multiple uterotonics and internal iliac artery embolization. Because of agitation she required emergency tracheal intubation. Her hemoglobin concentration dropped from a preoperative value of 12mg/dL to 3mg/dL on postoperative day one. She was acidotic, requiring vasopressors for hemodynamic stability and remained ventilated and sedated. She was treated with daily erythropoietin, iron therapy and cyanocobalamin. Because of ongoing hemorrhage, continued acidemia and vasopressor requirements she was co-treated with PEGylated carboxyhemoglobin bovine and hyperbaric oxygen therapy to reverse her oxygen debt. On postoperative day eight her hemoglobin concentration was 7mg/dL, she was hemodynamically stable and vasopressors were discontinued. She was extubated and discharged from the intensive care unit on postoperative day eight. This report highlights the multiple modalities used in treating a severely anemic patient who refused blood, the use of an investigational new drug, the process of obtaining this drug via the United States Food and Drug Administration emergency expanded access regulation for single patient clinical treatment, and ethical dilemmas faced during treatment.

Central cord syndrome: a rare neurological complication following hypotension during general anesthesia in an elderly patient.

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