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Biomedical subjects

H Sehgal

Publications and source records attributed to H Sehgal.

At least 19 recordsLinked to original sources
PubMed1997

Clinical utility of human polymerized hemoglobin as a blood substitute after acute trauma and urgent surgery.

We have previously documented the safety of 1 unit (50 gram) of human polymerized hemoglobin (Poly SFH-P) in healthy volunteers. This report describes the first patient trial to assess the therapeutic benefit of Poly SFH-P in acute blood loss. Thirty-nine patients received 1 (n = 14), 2 (n = 2), 3 (n = 15), or 6 (n = 8) units of Poly SFH-P instead of red cells as part of their blood replacement after trauma and urgent surgery. There were no safety issues related to the infusion of Poly SFH-P. The plasma hemoglobin concentration ([Hb]) after the infusion of 6 units (300 gram) of Poly SFH-P was 4.8 +/- 0.8 g/dL (mean +/- SD). Although the red cell [Hb] fell to 2.9 +/- 1.2 g/dL, the total [Hb] was maintained at 7.5 +/- 1.2 g/dL. Poly SFH-P maintained total [Hb], despite the marked fall in red cell [Hb] due to blood loss. The utilization of O2 (extraction ratio) was 27 +/- 16% from the red cells and 37 +/- 13% from the Poly SFH-P. Twenty-three patients (59%) avoided allogeneic transfusions during the first 24 hours after blood loss. Poly SFH-P effectively loads and unloads O2 and maintains total hemoglobin in lieu of red cells after acute blood loss, thereby reducing allogeneic transfusions. Poly SFH-P seems to be a clinically useful blood substitute.

Adult↗
PubMed1990

Physiologic effects of acute anemia: implications for a reduced transfusion trigger.

The risks of transfusion-associated infectious disease have led to a reassessment of transfusion practice, which in turn has resulted in a trend toward the reduction of homologous transfusion. This reduction is primarily due to the initiation of hemotherapy at more severe levels of anemia. The optimum threshold for the initiation of transfusion therapy, or the transfusion trigger (TT), is unknown. The purpose of this study is to evaluate the effects of withholding transfusion or lowering the TT to a hematocrit (Hct) of 15 percent in unanesthetized animals. Nineteen adult baboons underwent a laparotomy to simulate surgical stress. Upon their recovery from anesthesia, hemodynamic measurements were obtained, and the animals underwent an exchange transfusion (ET) with 6-percent hetastarch to a final Hct of 15 percent. After ET, hemodynamic measurements were repeated, and the animals were followed for 2 months. There was no morbidity after ET or during the 2-month observation period. After ET, there was a significant increase in both the cardiac output (3.3 vs. 2.5 L/min, p less than 0.001) and the oxygen extraction ratio (59.9 vs. 38.2%, p less than 0.0001). Oxygen delivery fell after ET (18.9 vs. 11.1 cc/kg/min, p less than 0.001), but there was no significant change in oxygen consumption after ET. The unanesthetized animals adapted well to severe anemia and experienced no adverse effects on their long-term survival in this setting, which suggests that the reduction of the TT to a Hct of 15 percent in normal animals is safe. Adoption of this TT could result in a significant reduction in the requirements for homologous transfusion with its attendant risks.

Acute Disease↗
PubMed1990

Accelerated erythropoiesis: the hidden benefit of autologous donation.

The risks associated with the administration of blood products have increased efforts to avoid homologous transfusions. Preoperative autologous donation has received renewed interest as a method of decreasing homologous transfusion requirements. Autologous donations may also stimulate postoperative erythropoiesis. The purpose of this study is to evaluate the effect of an aggressive autologous donation program on postoperative erythropoiesis. Ten adult male baboons were divided into two groups. The autologous group (n = 5) donated an average of 2 units of blood per week for 5 weeks before operation. The control group (n = 5) had no preoperative treatment. All animals then underwent a laparotomy and exchange transfusion with hetastarch to a final hematocrit of 15 percent. The time required to recover to hematocrits of 20 percent (3.3 vs. 5.7 days, p less than 0.01), 25 percent (7.0 vs. 8.8 days, p less than 0.05), and 30 percent (11.1 vs. 17.7 days, p less than 0.01) was shorter in the autologous group. The autologous group had more intense reticulocytosis during the first 4 postoperative days (p less than 0.03). The data show that participation in an aggressive autologous donation program improves the erythropoietic response to anemia in the postoperative setting. This represents a hidden benefit of preoperative autologous donations and suggests that more aggressive donation schedules may be clinically beneficial. Recognition of that acceleration of erythropoiesis by autologous donation could further reduce the need for transfusion of homologous blood.

Animals↗
PubMed1990

New dimensions to poliomyelitis.

About 22% of persons who suffer from acute paralytic poliomyelitis 20 to 30 years ago and were fully rehabilitated with maximal functional recovery began to experience new symptoms termed "Post-polio Sequelae" (PPS). These include unaccustomed fatigue, weakness in muscles previously affected or apparently unaffected, new joint pains, respiratory difficulties and intolerance to cold. Predictors for PPS are development of acute attack of paralytic polio before 10 years of age, involvement of all four limbs and having needed a ventilator during acute stage. The functional decompensation in PPS is presumed to be due to loss of normal neurones by aging and by metabolic fatigue of stressed neurones over passing years. Joint deformities due to muscular imbalance are also responsible for some of the symptoms. Treatment consists of reassurance and use of assistive devices and assistive exercises. The extent of problem of PPS is not known in India.

Humans↗
PubMed1982

Fluorocarbon emulsions: methodology to assess efficacy.

The fluorocarbon emulsion Fluosol-DA (20%) is an acellular O2 carrier that has potential as a red cell substitute. Clinical evaluation of efficacy requires knowledge of the ability of the perfluorochemical (pfc) phase to both load and unload O2. A method is described to measure the oxygen dissolved in the pfc and aqueous phases, and the oxygen chemically bound to hemoglobin, during use of this drug. These O2 contents are used to calculate the contribution of the pfc phase to total O2 delivery and O2 consumption (VO2) and the fractional extraction of O2 in the pfc phase. The technique requires a blood gas analyzer, a microhematocrit centrifuge, and a standard co-oximeter found in many blood gas laboratories. This technique appears to be simple and reliable, and should facilitate the evaluation of efficacy of fluorocarbon emulsions.

Animals↗