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R K Spence

Publications and source records attributed to R K Spence.

At least 37 records · Page 2Linked to original sources
PubMed1995

Perfluorocarbons in the twenty-first century: clinical applications as transfusion alternatives.

The risks of allogeneic transfusion are well known to physicians and have prompted a search for alternatives. Perfluorocarbons were introduced into clinical trials in the early 1980's with the hope that these products would develop into acceptable blood substitutes. Unfortunately, the limited potency, short half-life, and potential toxicity of these early formulations coupled with unrealistic expectations for efficacy prevented the perfluorocarbons from playing a significant role in transfusion medicine. Recent changes in formulation to improve efficacy and eliminate toxicity have stimulated renewed interest in perfluorocarbons as alternatives to allogeneic transfusion. Our recent work has focused on the role of perfluoroctylbromide (PFOB), a second generation perfluorocarbon, as an adjunct to autologous transfusion and acute normovolemic hemodilution (ANH), rather than as a total blood substitute. Initial animal experiments have shown the ability of small doses of PFOB to maintain oxygen delivery without the need for blood transfusion in the setting of hemodilution. Our presentation will focus on subsequent clinical work using PFOB as an alternative to both allogeneic and autologous blood transfusion during ANH. We believe that perfluorocarbons such as PFOB will have a significant role in the future as one of several, additive alternatives to blood transfusion.

Animals↗
PubMed1995

Practical nursing measures for vascular compromise in the lower leg.

Among the many factors that contribute to a nonhealing wound, circulatory compromise is a dominant variable. Regardless of whether the circulatory compromise is arterial or venous, the patient should be educated and supported in their efforts to quit smoking, minimize stress, achieve ideal body weight, limit fats in their diet, keep underlying disorders within check, and avoid a sedentary lifestyle. Patients with peripheral arterial disease (PAD) can maximize their tissue perfusion when nurses help them implement a few basic strategies into their lifestyles. Patients with chronic venous insufficiency (CVI) need to apply counterpressure and combat gravity to reduce venous hypertension, without which healing will not occur. When resources are limited, nurses can bridge the gap through coordination of care, patient teaching and support.

Humans↗
PubMed1995

Erythropoetin accelerates hematocrit recovery in post-surgical anemia.

UNLABELLED: We evaluated the role of recombinant human erythropoietin (RHE) for treatment of severe postsurgical anemia (Hct < 25%) in 40 Jehovah's Witness (JW) patients refusing transfusion. Twenty patients (group E) received RHE either at a loading dose of 300 U/kg iv 3 times/week for 1 week followed by 150 U/kg 3 times/week in accordance with an IRB approved protocol (N = 13), or at a dose of 100 U/kg 3 times/week for humanitarian reasons (N = 7). This group was compared to 20 similar JW patients who did not receive RHE (group C). All patients received iron restoration and nutritional support. Non-parametric analysis (Mann-Whitney) was used because of sample size. Entry hematocrit was similar for both groups: H(E)(0) = 15.8% +/- 1.1 SEM (8.5-23.4) vs HC (0) = 12.8% +/- 0.9 SEM (7.3-20.6), P = 0.09. After one week, hematocrit was significantly higher in group E (H(E)(1)) = 19.3 +/- 1.1 vs HC(1) = 12.5% +/- 0.9, P < 0.0005) as was the increase in hematocrit for group E (3.6% +/- 0.9 for E vs -0.4% +/- 0.8 for C, P < 0.005). Hematocrit change in Week 2 showed an increase for both groups (2.9 +/- 0.6 for E vs 4.9% +/- 1.2 for C, P = 0.12). CONCLUSIONS: Hct recovery shows a 1-week lag in severely anemic postsurgical patients treated without RHE. Exogenous RHE appears to accelerate hematocrit recovery in the first week. Use of RHE in the immediate postoperative period may help avoid or reduce homologous blood transfusion.

Anemia↗
PubMed1994

Preoperatively assessing and planning blood use for elective vascular surgery.

Few guidelines exist for determining transfusion needs and strategies, namely, the appropriate use of autologous versus homologous blood for elective vascular surgery. To address this deficiency, we have developed and used an algorithm based on an analysis of the procedure, maximum surgical blood ordering schedule, patient status, and patient suitability for autologous alternatives. Data were derived from consecutive major vascular procedures done at our hospital from 1991 to 1992. The algorithm helps the surgeon assess transfusion need and patient suitability for autologous predonation and aids in selecting appropriate transfusion alternatives. Using this algorithm during the past year with 120 patients, we simplified transfusion decisions, reduced homologous blood use (to only 4.2%), and reduced wasting of autologous blood to less than 5% of the units predonated. We believe that the use of this algorithm will aid the vascular surgeon in choosing appropriate alternatives to allogeneic blood transfusion, thereby reducing the patient's exposure to risk. The algorithm should also reduce wasting of autologous blood.

Adult↗
PubMed1994

Perfluorocarbons as blood substitutes: the early years. Experience with Fluosol DA-20% in the 1980s.

Clinical testing of perfluorocarbons (PFC) as blood substitutes began in the early 1980's in the form of Fluosol DA-20% (FDA), a mixture of perfluorodecalin and perfluorotripropylamine emulsified with Pluronic F68. We have treated 55 patients (Treatment (T) = 40; Control (C) = 15) with intravenous infusions of 30 cc/kg of FDA as part of either a randomized, clinical trial or a humanitarian protocol. All patients were Jehovah's Witnesses who refused blood transfusion and were severely anemic (mean hemoglobin = 4.6 g/d). FDA successfully increased dissolved or plasma oxygen content (P1O2 in ml/dl), but not overall oxygen content (T group: P1O2 baseline = 1.01 +/- .27, P1O2 12hrs = 1.58 +/- .47 [p = < .0001, t-test]; P1O2 12 hrs: T = 1.58 +/- .47, C = 1.00 +/- .31, p = < .0002, t-test). This effect persisted for only 12 hours post infusion, and had no apparent effect on survival. FDA is an ineffective blood substitute because of low concentration and short half-life. Improved emulsion design may resolve these problems, thereby producing a more effective agent. Our discussion will include a review of our data plus a summary of other reports of FDA efficacy as a blood substitute.

Anemia↗
PubMed1994

Improvement in circulatory and oxygenation status by perflubron emulsion (Oxygent HT) in a canine model of surgical hemodilution.

To examine the effect of a low dose of Oxygent HT on hemodynamics and oxygen transport variables in a canine model of profound surgical hemodilution, two groups of adult anesthetized splenectomized beagles were hemodiluted with Ringer's solution to Hb 7 g/dL. The treated group received 1 mL/kg Oxygent HT (90% w/v perflubron emulsion [perfluorooctyl bromide], Alliance Pharmaceutical Corp.) and both groups (7 controls and 10 treated) were further hemodiluted using 6% hydroxyethyl starch until cardiorespiratory decompensation occurred. Pulmonary artery catheterization data and oxygen transport variables were recorded at Hb decrements of 1 g/dL breathing room air. There was no difference among groups during initial hemodilution. However, in the Oxygent HT group there was a statistically significant improvement in mean arterial pressure, CVP, cardiac output, PvO2, SvO2, DO2, and pulmonary venous admixture shunt during profound hemodilution to Hb levels of 6, 5, and 4 g/dL. A low dose of Oxygent HT offered benefit in improving hemodynamics and oxygen transport parameters even under air breathing conditions in a model of surgical hemodilution. This effect was most apparent at lower levels of Hb.

Animals↗
PubMed1994

A survey of preferred approach to inguinal hernia repair: laparoscopic or inguinal incision?

The recent interest in laparoscopic surgery has raised some concerns that large numbers of surgeons were recommending this "minimally invasive" approach in procedures such as inguinal herniorrhaphy before the availability of adequate data regarding safety and benefits. To determine current experience and preference levels for laparoscopic inguinal herniorrhaphy (LH), we conducted a mail survey of New Jersey surgeons. Of 531 respondents, 430 (81%) preferred a traditional inguinal incision approach over a laparoscopic approach (8%). Of 344 general surgeon respondents, 227 (66%) had experience with laparoscopic cholecystectomy, but only 56 (16%) had experience with LH. This latter group had performed only an average of 9.2 laparoscopic herniorrhaphies, with a median of five cases. Most of these 56 surgeons with LH experience indicated a preference for inguinal incision herniorrhaphy although 19 surgeons who had performed 10 or more LH cases showed a slight preference for LH (11 to 8). The primary reasons for choosing LH included "less pain" and "quicker recovery." The primary reasons for choosing inguinal incision herniorrhaphy included having a "better known procedure" and avoiding general anesthesia. Our survey indicates that the laparoscopic approach to inguinal hernia repair has currently accumulated few proponents in the surgical community since many surgeons are waiting for more data on the procedure.

Hernia, Inguinal↗
PubMed1993

Transfusion and surgery.

In this survey of transfusion in surgery, we have attempted to provide the surgeon with an understanding of the problems associated with homologous transfusion and a practical knowledge of treatment strategies and alternatives designed to reduce homologous blood exposure. Such a review cannot be encyclopedic. Our hope is that it will serve the reader as a stimulus to examine his or her transfusion practices and as a guide for future self-learning.

Animals↗
PubMed1993

Safety of teaching laparoscopic cholecystectomy to surgical residents.

As laparoscopic cholecystectomy evolves into the "standard" method for gallbladder removal, it has become necessary for surgical residents to safely acquired the necessary skills to perform the procedure. To determine the safety of this procedure in the hands of residents, the authors evaluated the first 100 attempted laparoscopic cholecystectomies performed by a resident in the role of "surgeon." Ninety-one of the 100 procedures were successfully completed laparoscopically and 9 required conversion to laparotomy: 5 technically difficult cases, 2 common duct explorations, and 2 for intraoperative complications. At Cooper Hospital in New Jersey, essentially all patients requiring cholecystectomy are first attempted laparoscopically. Seventy-seven patients had chronic cholecystitis and 23 had acute disease. Twenty-two patients had intraoperative cholangiograms and two had laparoscopic common bile duct exploration. For the laparoscopically-completed procedures, average operative time was 91 min and showed a downward trend as each resident gained experience. Three (3%) major complications occurred: one colon laceration, one common bile duct injury, and one postoperative bile collection. For the 91 laparoscopically-completed procedures, 53 patients were discharged on postoperative day 1 and 20 on postoperative day 2. Average postoperative hospitalization was 1.7 days. Overall, these results were comparable to those reported in the literature by attending and private surgeons. The authors conclude that laparoscopic cholecystectomy can be performed safely by supervised residents acting as primary surgeon with outcomes similar to those obtained by trained attending surgeons.

Cholecystectomy, Laparoscopic↗
PubMed1993

Complications of anticoagulation for pulmonary embolism in low risk trauma patients.

Trauma patients are at significant risk for deep venous thrombosis (DVT) and pulmonary embolism (PE). Anticoagulation is standard therapy for DVT/PE, but may cause severe complications. We reviewed the course of 70 trauma ICU patients treated over a 28-month period. Thirty-six patients (51.4 percent) were treated by continuous IV heparin and/or oral warfarin. Of these, 13 patients (36 percent) developed complications requiring termination of anticoagulation. These included recurrent PE (four), subdural hematomas (three), hemothorax (two), heparin-induced thrombocytopenia (one), hemorrhagic pericardial effusion (one), retroperitoneal hematoma (one), and sudden unexplained drop in hemoglobin and shock (one). All patients with subdural hematomas had no prior evidence of head injury on brain computed tomography. All patients with recurrent PE received adequate anticoagulation therapy. Age > 55 was associated with increased risk of complications (8 of 13; p = .02:chi 2). Thirty-four other patients (48.6 percent) received inferior vena caval filters with no related complications or deaths. Anticoagulation for DVT/PE should be used selectively in trauma patients and avoided in elderly patients. Such patients should undergo early caval filter placement.

Adult↗