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Biomedical subjects

C P Henny

Publications and source records attributed to C P Henny.

At least 19 recordsLinked to original sources
PubMed2001

The effect of the transfusion of stored RBCs on intestinal microvascular oxygenation in the rat.

BACKGROUND: Although it is known that the transfusion of stored RBCs does not always improve tissue O(2) consumption under conditions of limited tissue oxygenation, the efficiency of O(2) delivery to the microcirculation by stored RBCs has never been determined. STUDY DESIGN AND METHODS: In a rat hemorrhagic shock model, the effects of resuscitation with fresh or 28-day-old RBCs stored in CPD plasma, saline-adenine-glucose-mannitol, and CPDA-1 plasma were investigated. Systemic hemodynamic and intestinal oxygenation measures were monitored. Intestinal microvascular PO(2) was determined with the O(2)-dependent quenching of palladium-porphyrin phosphorescence, and the RBC deformability was measured with a Laser-assisted optic rotational cell analyzer. RESULTS: Hemodynamic and oxygenation measures were significantly decreased during hemorrhagic shock. Intestinal oxygen consumption and mesenteric venous pO(2) were restored with the transfusion of both fresh and stored RBCs, except for CPD-stored RBCs. The intestinal microvascular pO(2) improved only with the transfusion of fresh RBCs. Deformability of the stored RBCs was significantly decreased. CONCLUSION: In contrast to that of fresh RBCs, the transfusion of stored RBCs did not restore the microcirculatory oxygenation, possibly because of impaired O(2) unloading, but, except for CPD-stored RBCs, the storage-induced changes were not enough to impair intestinal VO(2) and mesenteric venous pO(2).

Animals↗
PubMed2001

Critical hematocrit in intestinal tissue oxygenation during severe normovolemic hemodilution.

BACKGROUND: A critical point in oxygen supply for microvascular oxygenation during normovolemic hemodilution has not been identified. The relation between organ microvascular oxygen partial pressure (microPO2) and organ oxygen consumption (VO2) during a decreasing oxygen delivery (DO2) is not well understood. The present study was designed to determine the systemic hematocrit and organ DO2 values below which organ microPO2 and VO2 cannot be preserved by regulatory mechanisms during normovolemic hemodilution. METHODS: Eighteen male Wistar rats were randomized between an experimental group (n = 12), in which normovolemic hemodilution was performed with pasteurized protein solution (PPS), and a control group (n = 6). Systemic hemodynamic and intestinal oxygenation parameters were monitored. Intestinal microPO2 was measured using the oxygen-dependent quenching of palladium-porphyrin phosphorescence. RESULTS: Baseline values in hemodilution and control group were similar. Hemodilution decreased hematocrit to 6.2 +/- 0.8% (mean +/- SD). Constant central venous pressure measurements suggested maintenance of isovolemia. Despite an increasing mesenteric blood flow, intestinal DO2 decreased immediately. Initially, microPO2 was preserved, whereas mesenteric venous PO2 (P(mv)O2) decreased; below a hematocrit of 15%, microPO2 decreased significantly below P(mv)O2. Critical DO2 was 1.5 +/- 0.5 ml x kg(-1) x min(-1) for VO2, and 1.6 +/- 0.5 ml x kg(-1) x min(-1) for microPO2. Critical hematocrit values for VO2 and microPO2 were 15.8 +/- 4.6% and 16.0 +/- 3.5%, respectively. CONCLUSIONS: Intestinal microPO2 and VO2 were limited by a critical decrease in DO2 and hematocrit at the same time. Beyond these critical points not only shunting of oxygen from the microcirculation could be demonstrated, but also a significant correlation between intestinal microPO2 and VO2.

Analysis of Variance↗
PubMed2000

Are there simple measures to reduce the risk of HIV infection through blood transfusion in a Zambian district hospital?

OBJECTIVE: To quantify the potential impact of simple measures to reduce the risk of iatrogenic HIV infection through blood transfusion in a Zambian district hospital. METHODS: Three studies were conducted at St. Francis' Hospital, Katete, Zambia: (1) From 1991 to 1995 HIV seroprevalence among all listed blood donors and the impact of proper subgroup selection were studied retrospectively; (2) the sensitivity of locally used rapid antibody assays (HIV-spot/Wellcozyme HIV 1 & 2) for the detection of HIV in donor blood and the influence of the expiration date of the tests on this sensitivity were determined prospectively from June 1993 until March 1994 by screening all consecutive surgical patients and blood donors; (3) the number of unnecessary blood transfusions was determined retrospectively from January 1995 through January 1996 and prospectively from February 1996 through March 1996, and possibilities to reduce the total number of blood transfusions were considered. RESULTS: (1) Excluding prisoners, who have an HIV seroprevalence of 19-25%, from the donor population significantly reduces the overall HIV seroprevalence from 13-16% to 8-9% (P < 0. 01). (2) Under local circumstances the sensitivity of the used rapid antibody assays was 6.8-17.9% lower than claimed by the manufacturer. Usage of non-expired tests increased the sensitivity significantly from 88.2% to 91.7% (P < 0.05). (3) None of the 294 studied blood transfusions can be classified as inappropriate according to international standards. CONCLUSIONS: Simple measures such as proper subgroup selection among blood donors and correct use of non-expired tests may decrease the risk of iatrogenic HIV transmission. Stricter indications for blood transfusions will not substantially reduce the number of transfusions.

Blood Donors↗
PubMed2000

Preservation of intestinal microvascular Po2 during normovolemic hemodilution in a rat model.

The effect of hemodilution on the intestinal microcirculatory oxygenation is not clear. The aim of this study was to determine the effect of moderate normovolemic hemodilution on intestinal microvascular partial oxygen pressure (Po2) and its relation to the mesenteric venous Po2 (Pmvo2). Normovolemic hemodilution was performed in 13 anesthetized male Wistar rats. Systemic hemodynamic and intestinal oxygenation parameters were monitored. Intestinal microvascular Po2 was measured by using the oxygen-dependent quenching of palladium-porphyrin phosphorescence. Hemodilution decreased systemic hematocrit from 45.0% +/- 0.1% (average +/- SEM) to 24.6% +/- 1.6%. The mesenteric blood flow did not change from baseline values, resulting in a linear decrease in intestinal oxygen delivery (from 2.77 +/- 0.15 to 1.42 +/- 0.11 mLxkg(-1)xmin(-1)). The intestinal oxygen extraction ratio increased significantly from 24% +/- 1% to 42% +/- 4%. Pmvo2 decreased significantly (from 57 +/- 2 to 41 +/- 2 mm Hg), but intestinal oxygen consumption and microvascular Po2 remained unaffected. As a result, the difference between microvascular Po2 and Pmvo2 increased significantly during hemodilution. Intestinal microvascular Po2 and oxygen consumption were well preserved during moderate normovolemic hemodilution. These results might be explained by the notion of others that hemodilution induces recruitment of capillaries, resulting in redistribution of the intestinal blood flow in favor of the microcirculation, which allows a more efficient extraction of oxygen. These findings further indicate that the use of venous Po2 values as indicators of microvascular oxygenation may be misleading.

Animals↗
PubMed2000

The effect of the administration of recombinant activated factor VII (NovoSeven) on perioperative blood loss in patients undergoing transabdominal retropubic prostatectomy: the PROSE study.

Transabdominal retropubic prostatectomy is associated with significant perioperative blood loss, often requiring blood transfusion. However, the administration of allogeneic blood and blood products may induce serious immunological or infectious complications. Several studies show that recombinant activated factor VII (rFVIIa; NovoSeven, Novo Nordisk A/S, Bagsvaerd, Denmark) induces short-term local hemostasis. This ongoing study will evaluate the safety and efficacy of rFVIIa on blood loss in patients with normal coagulation undergoing retropubic prostatectomy. Thirty-six patients will be randomized to three different dose levels and receive either rFVIIa as a single intravenous bolus dose or saline. Perioperative blood loss will be assessed from blood-volume suction containers and drains. Blood sample analysis, physical examination and electrocardiography will be performed postoperatively. Eighteen patients have enrolled in the study. Blood loss was 630-4455 ml (mean = 1698 ml), while the number of red cell transfusions varied between 0 and 4 units (mean = 0.9 units). None of the patients developed venous thromboembolism. An independent committee performed an interim analysis after patient 12 and identified a positive trend between treatment groups (not statistically significant). Although a single bolus injection of rFVIIa appears to decrease perioperative blood loss safely and effectively, definite conclusions must await study completion.

Blood Loss, Surgical↗
PubMed1998

[Excess mortality in critically ill patients after treatment with human albumin].

According to the results of a systematic review of randomized clinical studies administration of human albumin to critically ill patients is associated with excess mortality, compared with withholding albumin or administration of crystalloid fluids. The study appears to be well done. Also, there are various explanatory pathophysiological mechanisms supporting the association. However, a favourable effect of albumin in certain patient groups cannot be excluded. Alternatives to albumin are available in most clinical situations, but unfortunately, they are not completely without drawbacks. The use of albumin has to be limited; it might only be abolished when a better effect of other fluids, such as synthetic solutions, is demonstrated.

Albumins↗
PubMed1996

Differences in peripheral arterial and venous hemorheologic parameters.

To evaluate the comparability of hemorheologic parameters in arterial and venous blood, we measured hematocrit, whole blood viscosity, plasma viscosity, erythrocyte deformability, erythrocyte aggregation, and erythrocyte indices in both arterial and venous blood from 20 consecutive patients scheduled for coronary artery surgery and/or valve replacement surgery. Hematocrit, whole blood viscosity at three shear rates (0.05 s-1, 0.5 s-1, and 70 s-1), plasma viscosity, and erythrocyte aggregation factor were statistically significantly higher in venous blood than in arterial blood. The differences may be explained by the difference in hematocrit. Erythrocyte deformability did not differ significantly. With the availability of more precise rheological measurement techniques, differences such as those encountered in this study may be of importance in clinical studies. It is concluded that arterial and venous blood samples are not entirely rheologically comparable.

Aged↗
PubMed1996

The routine use of fresh frozen plasma in operations with cardiopulmonary bypass is not justified.

BACKGROUND: The negative influence of cardiopulmonary bypass on hemostasis has been documented. Although abnormalities in platelet function are reported as the major cause of postoperative blood loss related to this hemostasis defect, fresh frozen plasma is often used in operations with cardiopulmonary bypass because it is thought to contribute to the reduction of postoperative bleeding complications. This study was designed to evaluate the effect of the administration of fresh frozen plasma after cardiopulmonary bypass on blood loss, transfusion requirements, and a number of coagulation parameters. METHODS: In a prospective, randomized, double-blind clinical trial 50 patients (mean age 63 years; 35 men/15 women) undergoing elective operation with cardiopulmonary bypass were randomly assigned to one of two groups: group I (n = 24) received 3 units of fresh frozen plasma after operation and group II (n = 26) received an equal amount of Gelofusine plasma substitute. At seven points before, during, and after operation hemoglobin concentration, hematocrit level, thrombocyte count, and coagulation parameters were analyzed. Study endpoints were the volume of blood loss and the transfusion requirement. RESULTS: There were no significant differences between the two study groups in blood loss, transfusion requirement, coagulation parameters, or thrombocyte counts. CONCLUSION: The routine use of fresh frozen plasma in operations with cardiopulmonary bypass cannot be recommended.

Aged↗
PubMed1996

A pilot study of the effects of a perflubron emulsion, AF 0104, on mixed venous oxygen tension in anesthetized surgical patients.

A pilot study of a perfluorochemical (PFC) emulsion was undertaken to determine whether administration of a perflubron emulsion could result in measurable changes in mixed venous oxygen tension. Seven adult surgical patients received a 0.9-g PFC/kg intravenous dose of perflubron emulsion after acute normovolemic hemodilution (ANH). Hemodynamic and oxygen transport data were collected before and after ANH, immediately after PFC infusion, and at approximate 15-min intervals throughout the surgical period. There were no clinically significant hemodynamic changes associated with the administration of the PFC emulsion. There was a significant increase in mixed venous oxygen tension (PVO2) after the PFC infusion, while cardiac output and oxygen consumption were unchanged. As surgery progressed, the hemoglobin concentration decreased with ongoing blood loss while PVO2 values remained at or above predosing levels. Peak perflubron blood levels were 0.8 g/dL immediately postinfusion, and approximately 0.3 g/dL at 1 h. This pilot study demonstrates that administration of perflubron emulsion results in measurable changes in mixed venous oxygen tension during intraoperative ANH.

Aged↗
PubMed1995

Hemorrheological changes associated with brain death and their implications for potential organ donors.

Successful transplantation of donor organs from brain-dead patients requires adequate maintenance of hemodynamic parameters. Blood flow and tissue perfusion are highly dependent upon hemorrheology. The aim of the present study was to evaluate hemorrheological parameters in potential organ donors compared to healthy volunteers. Whole blood-, plasma- and corrected blood viscosity, hematocrit, erythrocyte deformability, and erythrocyte aggregation were obtained in ten consecutive brain-dead patients and ten matched volunteers. Compared to controls, hematocrit and whole blood viscosity at high and medium shear rates and erythrocyte deformability were significantly decreased. Plasma viscosity was significantly increased in all patients. In the same group, a highly significant increase was observed at all shear rates when viscosity was corrected for hematocrit. Definite rheological abnormalities were found in the blood of brain-dead patients, something which might lead to impaired organ function after transplantation. Therefore, optimizing such parameters by special fluid management may be of importance in potential organ donors.

Adolescent↗
PubMed1994

Red blood cell velocity in nailfold capillaries during hyperbaric oxygenation.

Microcirculatory hemodynamics of the skin during hyperbaric oxygenation were assessed by determination of nailfold capillary red blood cell velocity (Vrbc). Under hyperbaric conditions a continuous increase in Vrbc was found. Control values, 0.43 +/- 0.12 mm. sec-1 (mean +/- sem), were significantly (P < 0.05) lower compared with Vrbc at the end of hyperbaric oxygenation (0.62 +/- 0.16 mm.sec-1).

Adult↗
PubMed1993

Cytomegalovirus infection in the pregnant women.

Cytomegaloviruses (CMV) commonly infect man but overt disease only occurs in few patients; in the vast majority the infection is subclinical. We report on a HIV-negative pregnant woman. She suffered from a life-threatening ulcerating colitis due to CMV infection for which laparotomy was indicated. The case history is presented and suggestions are given for the surgical treatment of gastrointestinal complications such as haemorrhage, toxic colitis and perforation. Although CMV disease usually occurs in immunocompromised patients such as AIDS patients and transplant recipients, one should always keep the possibility of CMV infection in mind. The gastrointestinal tract is one of the sites of infection where the colon and terminal ileum are most frequently involved in complications such as bleeding and perforation. Gastrointestinal complications of CMV infection, although rare, can be life threatening and often require extensive surgery.

Adult↗
PubMed1993

The effects of propofol compared to high-dose fentanyl anesthesia on rheologic parameters in coronary artery surgery.

Propofol has previously been found to decrease hematocrit values. Because hematocrit is an important determinant of blood viscosity, lower hematocrits may cause a decrease in blood viscosity, improving blood flow and oxygen delivery. This phenomenon may be beneficial in certain intraoperative situations. To study the influence of two anesthetic techniques on a variety of rheologic parameters, 32 patients scheduled for coronary artery bypass grafting (CABG) were divided into two groups. Group I (n = 18) was induced with high-dose fentanyl anesthesia (100 micrograms/kg), and group II (n = 16) with a combination of propofol and fentanyl anesthesia (1 to 1.5 mg/kg and 35 to 50 micrograms/kg, respectively). Maintenance anesthesia continued with infusions of the same drugs. Blood and plasma viscosity, hematocrit, erythrocyte aggregation factor, and erythrocyte deformability were measured preoperatively, intraoperatively, and up to 48 hours postoperatively. Whole blood viscosity was corrected to a standard hematocrit of 0.45. The two groups were comparable with respect to age, bypass duration, blood loss, urine output, transfusions, and fluid management. Erythrocyte deformability did not decrease during or after cardiopulmonary bypass (CPB). In both groups, hematocrit and blood and plasma were decreased significantly during and after CPB (P < 0.01) and returned to baseline levels 48 hours after surgery. After induction and before CPB, blood viscosity was only decreased in group II. However, the corrected blood viscosity was significantly elevated at all shear rates in group II compared to group I at 24 and 48 hours postoperatively (P < 0.01). In group II at these sampling times, this parameter was also significantly elevated compared to preoperative values.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Skeletal muscle PO2 in anaerobic soft tissue infections during hyperbaric oxygen therapy.

In the present study skeletal muscle PO2 measurements were performed in patients with gas gangrene and anaerobic soft tissue infections before, during and after hyperbaric oxygen therapy. Polarographic PO2 needle electrodes appeared to be suitable for application during different ambient pressures. We found that patients with gas gangrene revealed higher skeletal muscle PO2 values than patients with an anaerobic soft tissue infection. This may be explained by a higher metabolic rate within the anaerobically infected soft tissues. The higher PO2 values in gas gangrene may be caused by alpha toxins, affecting cellular and intracellular membranes thus destroying PO2 diffusion barriers.

Bacteria, Anaerobic↗