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A Trouwborst

Publications and source records attributed to A Trouwborst.

At least 19 recordsLinked to original sources
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

Systemic haemodynamics and oxygenation during haemodilution in children.

Transfusion of homologous blood should be avoided when possible, and one technique that diminishes perioperative requirement for donor blood is haemodilution. In children its effects on systemic haemodynamics and systemic oxygenation have not been reported. Six children aged 4-12 yr were anaesthetised for major surgery and blood was withdrawn to reduce packed cell volume to 25%. Cardiac index increased from 3.1 (SD 0.5) L min-1 m-2 at baseline to 4.4 (0.5) L min-1 m-2 at the end of surgery, when packed cell volume was 16 (1)%; this change, compensating for the decline in oxygen carrying capacity, was associated with a fall in systemic vascular resistance and a rise in stroke volume. Oxygen extraction from haemoglobin rose from 0.22 (0.05) to 0.33 (0.06). Perioperative blood loss was 40% of circulating blood volume; however, owing to reinfusion of autologous blood (and use of a cell saver in three patients), the haemoglobin one day after operation was only 19% lower than preoperatively (9.9 [1.5] vs 12.5 [2.5] g/dL). In this study, children seemed at least as able as adults to compensate for the effects of haemodilution, which allowed major surgery without transfusion of homologous blood.

Anesthesia↗
PubMed1994

Transesophageal echocardiographic monitoring of preoperative acute hypervolemic hemodilution.

BACKGROUND: Preoperative acute hypervolemic hemodilution is used in anesthesia to reduce the loss of blood cells during intraoperative bleeding. Indications for use of the technique might be broadened if it can be shown to be safe in older as well as younger patients. Few data are available describing heart function in humans subjected to hypervolemic hemodilution. METHODS: Nineteen anesthetized Jehovah's Witnesses (ages 22-70 yr) without evidence of heart disease had hypervolemic hemodilution before surgery in three stages, each consisting of an infusion of 500 ml dextran 40 (50 g/l) and 500 ml Ringer's lactate over a 10-min period. After each stage, the size and function of the left ventricle were recorded by transesophageal cross-sectional echocardiography in the short-axis view. Simultaneously heart rate, arterial blood pressure, pulmonary arterial and wedge pressures and cardiac output were recorded, to compare the echocardiographic and hemodynamic data. RESULTS: No complications occurred. Hypervolemic hemodilution resulted in an increased cardiac output by increasing the stroke volume from 48 ml in basal conditions to 67, 71, and 72 ml over the three stages, whereas heart rate did not increase. There was an initial increase in end-diastolic volume of the left ventricle, as assessed from the cross-sectional end-diastolic area from 12.9 to 15.5, 16.6, and 16.9 cm2 followed by a decrease in the in cross-sectional end-systolic area from 6.3 to 6.8, 6.0, and 5.7 cm2. The increase in wedge pressures (from 5.9 to 12.4, 17.9, and 22.6 mmHg) did not lead to progressive cardiac dilation. There was a curvilinear relation between wedge pressure and cross-sectional end-diastolic area. Stroke volume did not decrease, nor did cross-sectional end-systolic area increase; instead, a decrease in end-systolic area was a common observation. CONCLUSIONS: The described regimen of acute hypervolemic hemodilution is well tolerated during anesthesia by patients without heart disease and does not lead to cardiac failure. It leads to an increase in stroke volume that is generated initially from an increase in end-diastolic volume, followed in many patients by a decrease in end-systolic volume, the mechanism of which is as yet unclear.

Adult↗
PubMed1992

Catecholamines and regional hemodynamics during isovolemic hemodilution in anesthetized pigs.

The effects of stepwise isovolemic hemodilution on systemic and regional hemodynamics, oxygen flux, and circulating catecholamines were studied in six pigs anesthetized with midazolam and fentanyl. Reduction of the hematocrit from 28 to 9% resulted in doubling of the cardiac output, mainly due to an increase in stroke volume. Regional blood flows, measured using the radioactive microsphere technique, showed an increase in blood flow to all organs except liver (hepatic artery fraction) and adrenals, with a redistribution of cardiac output in favor of heart and brain (increase in blood flow 420 and 170%, respectively). Oxygen flux to most organs did not decrease until hematocrit decreased to 9%, while total body oxygen consumption was well maintained. Left ventricular oxygen consumption increased, but because left ventricular blood flow also increased, left ventricular extraction ratio did not increase. Circulating catecholamines did not play any role in these regulatory mechanisms.

Anesthesia↗
PubMed1991

Accuracy of a mixed venous saturation catheter during acutely induced changes in hematocrit in humans.

OBJECTIVE: To determine the accuracy of in vivo mixed venous hemoglobin saturation (Svo2) measurements with a fiber optic thermodilution catheter during acute changes in hematocrit. DESIGN: Comparison of fiberoptic in vivo Svo2 values with in vitro Svo2 values obtained with a multiwavelength spectrophotometer. SETTING: Operating room in a university hospital. PATIENTS: Six consecutive patients who are Jehovah's Witnesses. MEASUREMENTS AND MAIN RESULTS: Before and after each step of hypervolemic hemodilution and after every 500 mL of blood loss, blood gases were analyzed and hemodynamic, hemoglobin, hematocrit, and in vitro and in vivo Svo2 measurements were made. Hematocrit values were measured in the range of 40% to 18%. Plotting all in vivo Svo2 values (n = 74) against the in vitro Svo2 measurements obtained during the entire study period gives r2 = .86. The accuracy of in vivo Svo2 measurements was not affected by changes in hematocrit or cardiac output. The Svo2 catheter value at the beginning of the study differed from the in vitro Svo2 value by -0.86 +/- 2.56% and at the end of the study period of 8 to 10 hrs by 0.71 +/- 3.04%. CONCLUSIONS: The accuracy of the studied fiberoptic continuous measuring Svo2 system was not affected by changes in hematocrit or cardiac output. No significant drift in the in vitro Svo2 measurements was observed.

Adult↗
PubMed1990

Acute hypervolaemic haemodilution to avoid blood transfusion during major surgery.

16 patients underwent acute hypervolaemic haemodilution with dextran 40 and Ringers lactate, to see whether this procedure could avoid preoperative blood transfusion. Packed cell volume (PCV) and oxygen extraction decreased, and cardiac index and pulmonary wedge pressure increased, although end-systolic area was unchanged. PCV was not significantly different between patients who lost less than or greater than 20% of their initial blood volume. This preoperative manoeuvre, which reduces loss of red blood cells, allowed major surgery to be completed safely without blood transfusion.

Adult↗
PubMed1990

Safety and efficacy of xenon in routine use as an inhalational anaesthetic.

40 patients (24 male, 16 female, aged 21-59 years) of American Society of Anesthesiologists class I or II who were undergoing routine surgery took part in a randomised, double-blind comparison of the anaesthetic efficacy and potency of xenon and nitrous oxide and their effects on the circulatory and respiratory systems. During anaesthesia, for each rise in blood pressure of more than 20% of the preanaesthetic (baseline) value, the patient received 0.1 mg fentanyl. The total amount of fentanyl required per patient was used as an index of the anaesthetic potency of the study gases. Patients in the xenon group required on average only 0.05 mg fentanyl, whereas those in the nitrous oxide group required 0.24 mg fentanyl; the duration of anaesthesia was similar in the two groups. Changes in blood pressure were significantly greater throughout the study in the nitrous oxide than in the xenon group. Thorax-lung compliance fell during the study period in the nitrous oxide group but not in the xenon group. Thus, xenon is a potent and effective anaesthetic which can be safely used under routine conditions.

Adult↗
PubMed1990

Cardiovascular responses, hemodynamics and oxygen transport to tissue during moderate isovolemic hemodilution in pigs.

In conclusion, in contrast to many reports obtained from dogs, in pigs the rise in CO during moderate isovolemic hemodilution is, besides the increased venous return, more induced by increased work performance of the heart and less by a decreased SVR. The rise in CO did not compensate for the decrease in oxygen transport capacity. Our results confirm most of the reported findings in humans at the same stage of hemodilution. Besides changes in hemodynamics, in our study a gradual decreased oxygen affinity of hemoglobin could be observed. That the pig animal model for studying hemodilution and oxygen transport to the tissue is more appropriate than the dog model is open to discussion.

Animals↗
PubMed1990

Hypervolaemic haemodilution in an anaemic Jehovah's Witness.

We report the effects of acute hypervolaemic haemodilution, induced before operation, on haemodynamics and systemic oxygenation. Major surgery in an anaemic Jehovah's Witness patient was facilitated with this technique. Some hours after operation, a perioperative decrease in haemoglobin concentration of less than 5% was observed, in spite of a blood loss of nearly 50% of the calculated blood volume.

Adult↗
PubMed1990

Blood gas analysis of mixed venous blood during normoxic acute isovolemic hemodilution in pigs.

Mixed venous oxygen saturation of hemoglobin (SvO2) and mixed venous oxygen tension (PvO2) may reflect the overall balance between oxygen consumption and delivery. Because of the potential value of monitoring SvO2 and PvO2 as indications of the state of tissue oxygenation, the aim of this study was to determine, during normoxic acute isovolemic hemodilution in pigs, the critical PvO2, critical SvO2, and critical oxygen extraction ratio (ER) at which oxygen uptake starts to decline during further induced hemodilution. During stepwise induced isovolemic hemodilution, a gradual decline in SvO2 and PvO2 was observed in all animals. The mean +/- SD of the critical PvO2 of six animals was 32.3 +/- 3.1 mm Hg. The mean +/- SD of the critical SvO2 was 44.2% +/- 7.9%. The ER increased gradually. At an ER of 0.57 +/- 0.08, oxygen uptake started to decline. A significant correlation was found between changes in SvO2 and changes in ER. These degrees of hemodilution were accompanied by an increase in cardiac index, pulmonary wedge pressure, heart rate, and left ventricular stroke work index. Only a slight decrease in systemic vascular resistance was observed. We conclude that measurements of PvO2 and SvO2 can be used as indicators of the critical point of hemodilution and that the SvO2 during hemodilution reflects the overall balance between oxygen uptake and oxygen delivery, confirmed by the strong correlation found between SvO2 and oxygen extraction ratio.

Animals↗