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Biomedical subjects

U Kreimeier

Publications and source records attributed to U Kreimeier.

At least 19 recordsLinked to original sources
PubMed2004

[Priority-oriented shock trauma room management with the integration of multiple-view spiral computed tomography].

In major trauma it is essential to immediately recognize and treat life-threatening problems and conditions. Most trauma protocols reserve the use of computed tomography for the secondary survey, as patients cannot be attended to during the examination and must be transferred from the emergency room to the CT suite. The relevant reduction in the scanning time of multidetector computed tomography (MDCT) or multislice computed tomography (MSCT) justifies its use as the major diagnostic adjunct for primary trauma survey and initial resuscitation. According to our ATLS((R))-based trauma algorithm, the multidetector scanner situated in the emergency department is utilized immediately after the correction of respiratory problems to detect causes of bleeding or intracranial hematomas. In a prospective series a total of 125 consecutive major trauma patients were evaluated. After focused sonography in trauma (FAST) and plain chest films in intubated patients, whole body MDCT was performed. By retrieving data from our trauma registry and a picture archiving and communication system (PACS), time from trauma room admission to the end of head CT scan for the entire MDCT study and calculation of multiplanar reconstruction (MPR) was analyzed. Additionally, relevant complications such as untreated tension pneumothorax or circulatory arrest during MDCT examination were recorded. The time from admission to the trauma room until completion of head CT scan without contrast was 21:12 min (median, IQR 18:13-27:52). The entire contrast-enhanced MDCT study, including pilot scan and contrast application, required 6:08 min (median, IQR 4:33-8:14) with a total scanning time of 0:59 min (median, IQR 0:55-1:03). MPR calculation of the spine and bony pelvis was performed in 11:37 min (median, IQR 8:03-16:41). A relevant life-threatening complication due to CT scanning during primary trauma survey was not observed in the 125 cases (0/125 CI 95% 0%-3%). Complete diagnostic imaging can be performed within 30 min after trauma room admission by using MDCT. During the primary survey, treatment of the patient is interrupted just for the few minutes of the CT scan and contrast application. An adequate survey of injuries can be achieved earlier and a targeted therapy can be initiated ahead of time. Integration of MDCT scanners in the primary trauma survey provides a high standard of imaging in a very short time without endangering the patient. When dealing with multiple casualties, MDCT could be used also as an accurate and time-efficient means of hospital triage to diagnose and prioritize patients and to plan further surgical interventions and intensive care.

Critical Care↗
PubMed2002

[Permissive hypotension in severe trauma].

Hemodynamic instability in the polytraumatized patient is a predominant feature and most commonly secondary to blood loss accompanying injury. In these patients restoration of intravascular volume attempting to achieve normal systemic pressure faces the risk of increasing blood loss and thereby potentially affecting mortality. Due to the lack of controlled clinical trials in this field, the growing evidence that "hypotensive resuscitation" results in improved long-term survival and improved neurologic outcome, mainly stems from experimental studies in animals. In patient care, several concepts exist for the reduction of blood loss in conjunction with systemic hypotension: these involve "deliberate hypotension" (synonym "controlled hypotension", used intraoperatively under conditions of normovolemia and stable hemodynamics), "delayed resuscitation" (where the hypotensive period is intentionally prolonged until operative intervention), and "permissive hypotension" (synonym "hypotensive resuscitation", where all kinds of therapy are commenced including fluid therapy, thereby increasing systemic pressure without, however, reaching normotension). In this review the concept of "permissive hypotension" is delineated on the basis of macro- and microcirculatory changes secondary to hypovolemia and low driving pressure, and potential indications as well as limitations for the care of the traumatized patient are discussed.

Blood Pressure↗
PubMed2002

Microvascular changes during anesthesia: sevoflurane compared with propofol.

BACKGROUND: We have developed a non-invasive computer-assisted venous congestion plethysmograph to measure the microvascular parameters in the lower limbs. This enables the assessment of microvascular changes following the induction of standardized anesthesia with either sevoflurane or propofol. METHODS: In a prospective randomized trial we measured the capillary filtration coefficient (CFC), isovolumetric venous pressure (Pvi), an index of the balance of Starling forces, and limb blood flow 24 h preoperatively, immediately after induction of anesthesia and on the 1st and 2nd postoperative day. Anesthesia was maintained with either 1.0% sevoflurane and 5 microg/kg/h remifentanil or propofol (3 mg/kg/h), and 5 microg/kg/h remifentanil in 20 female patients undergoing breast surgery. RESULTS: Preoperatively we found no significant differences between the mean CFC values of the sevoflurane group (3.7+/-0.3 ml/min 100 ml tissue/mmHg x 10-3=CFCU) and the propofol group (3.5+/-0.3 CFCU). In the sevoflurane group CFC decreased significantly to 2.9+/-0.2 CFCU, whereas it was unchanged in the propofol group. Both groups revealed a significant reduction in Pvi during steady-state anesthesia. Limb blood flow remained unchanged. There was an overall significant positive correlation between the perioperative fluid substitution and the difference between the preoperative and intraoperative CFC values (r = 0.64, P<0.01). CONCLUSION: The decreased CFC in response to sevoflurane may result in less extravasation of fluids into the interstitial space, thereby reducing intraoperative fluid requirements. These data suggest that sevoflurane may be the preferred anesthetic agent in subjects susceptible to large intraoperative fluid shifts.

Adult↗
PubMed2001

[Changes in blood volume during acute normovolemic hemodilution with 5% albumin or 6% hydroxyethylstarch and intraoperative retransfusion].

QUESTION: What is the impact of acute preoperative normovolemic hemodilution (ANH) on blood volume, intravascular colloid, and loss of red cells in the perioperative period? METHODS: In 20 patients undergoing radical hysterectomy, preoperative ANH was performed to a hematocrit of 22% using 5% albumin (albumin group; n = 10) or 6% hydroxyethylstarch solution (HES group; n = 10). Intraoperative retransfusion of ANH blood was started at a hematocrit of 18%. Plasma volume (indocyanine green-dilution technique), hematocrit, and plasma protein concentration were measured before and after ANH, before retransfusion, and postoperatively. Red cell volume (labelling erythrocytes with fluorescein) was determined before and after ANH and postoperatively. In the HES group hydroxyethylstarch concentrations were measured in plasma and urine. RESULTS: After removal of about 1,500 ml of blood and replacement with 15% more colloid solution, the blood volume was maintained in both groups after ANH. After a mean blood loss of about 1,800 ml, an average of 150 ml of red cells were saved due to ANH in both groups. CONCLUSIONS: Double label measurements of blood volume demonstrated that with the colloids used a surplus of 15% of colloid infusion in relation to blood removal was necessary to generate isovolemia after ANH.

Adult↗
PubMed2001

Changes in blood volume and hematocrit during acute preoperative volume loading with 5% albumin or 6% hetastarch solutions in patients before radical hysterectomy.

BACKGROUND: The impact of acute preoperative volume loading with colloids on blood volume has not been investigated sufficiently. METHODS: Before surgery, in 20 patients undergoing major gynecologic procedures, volume loading was performed during anesthesia by infusing approximately 20 ml/kg of colloid at a rate of 90 ml/min (group I: 5% albumin solution; group II: 6% hetastarch solution; n = 10 each). Plasma volume (indocyanine green dilution technique), erythrocyte volume (labeling erythrocytes with fluorescein), hematocrit, total protein, and hetastarch plasma concentrations (group II) were measured before and 30 min after the end of infusion. RESULTS: More than 1,350 ml of colloid (approximately 50% of the baseline plasma volume) were infused within 15 min. Thirty minutes after the infusion had been completed, blood volume was only 524 +/- 328 ml (group I) and 603 +/- 314 ml (group II) higher than before volume loading. The large vessel hematocrit (measured by centrifugation) dropped more than the whole body hematocrit, which was derived from double-label measurements of blood volume. CONCLUSIONS: The double-label measurements of blood volume performed showed that 30 min after the infusion of approximately 20 ml/kg of 5% albumin or 6% hetastarch solution (within 15 min), only mean 38 +/- 21% and 43 +/- 26%, respectively, of the volume applied remained in the intravascular space. Different, i.e., earlier or later, measuring points, different infusion volumes, infusion rates, plasma substitutes, or possibly different tracers for plasma volume measurement might lead to different results concerning the kinetics of fluid or colloid extravasation.

Adult↗
PubMed2001

Effects of hypertonic saline on expression of human polymorphonuclear leukocyte adhesion molecules.

Hypertonic saline prevents vascular adherence of neutrophils and ameliorates ischemic tissue injury. We hypothesized that hypertonic saline attenuates N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated expression of adhesion molecules on human polymorphonuclear leukocytes (PMNLs). fMLP-stimulated up-regulation of beta2-integrins was diminished by hypertonic saline but not by hypertonic choline chloride-, mannitol-, or sucrose-modified Hanks' buffered salt solution. Shedding of L-selectin was decreased by hypertonic saline and choline chloride but not by hypertonic mannitol or sucrose. When the effects of hypertonic sodium chloride- and choline chloride-modified media were compared, neither solution affected fMLP-receptor binding but both equally inhibited fMLP-stimulated increase in intracellular calcium, ionophore A23187, and phorbol myristate acetate (PMA)-stimulated numerical up-regulation of beta2-integrins. Analysis of mitogen-activated protein (MAP) kinases p38 and p44/42 for phosphorylation revealed that hypertonic solutions did not differ in preventing fMLP-stimulated increases in phospho-p38 and phospho-p44/42. Resting PMNLs shrunk by hypertonic saline increased their volume during incubation and further during chemotactic stimulation. Addition of amiloride further enhanced inhibition of up-regulation of beta2-integrins. No fMLP-stimulated volume changes occurred in PMNLs exposed to hypertonic choline chloride, resulting in significant cell shrinkage. Results suggest a sodium-specific inhibitory effect on up-regulation of beta2-integrins of fMLP-stimulated PMNLs, which is unlikely to be caused by alterations of fMLP receptor binding, decrease in cytosolic calcium, attenuation of calcium or protein kinase C-dependent pathways, suppression of p38- or p44/42 MAP kinase-dependent pathways, or cellular ability to increase or decrease volumes.

CD18 Antigens↗
PubMed2000

Permissive hypotension.

In trauma patients restoration of intravascular volume in an attempt to achieve normal systemic pressure faces the risk of increasing blood loss and thereby potentially affecting mortality. Due to the lack of controlled clinical trials in this field, the growing evidence that hypotensive resuscitation results in improved long-term survival mainly stems from experimental studies in animals. The main differences between concepts for the reduction of blood loss in systemic hypotension are between "deliberate hypotension" (synonym "controlled hypotension", used intraoperatively), "delayed resuscitation" (where the hypotensive period is intentionally prolonged until operative intervention) and "permissive hypotension" (where restrictive fluid therapy increases systemic pressure without reaching normotension). In this review the concept of "permissive hypotension" is delineated on the basis of macro- and microcirculatory changes secondary to hypovolaemia and low driving pressure, and the potential indications and limitations are discussed.

Humans↗
PubMed2000

Pathophysiology of fluid imbalance.

Fluid imbalance can arise due to hypovolemia, normovolemia with maldistribution of fluid, and hypervolemia. Trauma is among the most frequent causes of hypovolemia, with its often profuse attendant blood loss. Another common cause is dehydration, which primarily entails loss of plasma rather than whole blood. The consequences of hypovolemia include reduction in circulating blood volume, lower venous return and, in profound cases, arterial hypotension. Myocardial failure may result from increased myocardial oxygen demand in conjunction with reduced tissue perfusion. Finally, anaerobic metabolism due to reduced perfusion may produce acidosis and, together with myocardial dysfunction, precipitate multi-organ failure. The splanchnic organs are particularly susceptible to the deleterious effects of hypotension and hypovolemic shock, and these effects, depending upon their duration and severity, may be irreversible despite restoration of normovolemia by fluid administration. Patient monitoring in the intensive care unit typically relies upon central venous pressure devices, whereas the primary focus in the operating theater is blood volume deficit estimated from suction devices. However, estimates of intraoperative blood loss can be inaccurate, potentially leading to inappropriate fluid management. Normovolemia with maldistribution of fluid can be encountered in shock-specific microcirculatory disorders secondary to hypovolemia, as well as pain and stress. Consequent vasoconstriction and reduced tissue driving pressure, as well as leukocyte and platelet adhesion, and liberation of humoral and cellular mediators, may impair or abolish blood flow in certain areas. The localized perfusion deficit may contribute to multi-organ failure. Choice of resuscitation fluid may be important in this context, since some evidence suggests that at least certain colloids might be helpful in diminishing post-ischemic microvascular leukocyte adherence. Excessive volume administration may lead to fluid overload and associated impairment of pulmonary function. However, entry of fluid into the lungs may also be facilitated by increased vascular permeability in certain pathologic conditions, especially sepsis and endotoxemia, even in the absence of substantially rising hydrostatic pressure. Another condition associated with elevated vascular permeability is systemic capillary leak syndrome. The chief goal of fluid management, based upon current understanding of the pathophysiology of fluid imbalance, should be to ensure adequate oxygen delivery by optimizing blood oxygenation, perfusion pressure, and circulating volume.

Capillary Permeability↗
PubMed2000

Changes in intravascular volume during acute normovolemic hemodilution and intraoperative retransfusion in patients with radical hysterectomy.

BACKGROUND: Changes in blood volume during acute normovolemic hemodilution (ANH) and their consequences for the perioperative period have not been investigated sufficiently. METHODS: In 15 patients undergoing radical hysterectomy, preoperative ANH to a hematocrit of 24% was performed using 5% albumin solution. Intraoperatively, saline 0.9% solution was used for volume substitution, and intraoperative retransfusion was started at a hematocrit of 20%. Plasma volume (indocyanine green dilution technique), hematocrit, and plasma protein concentration were measured before and after ANH, before retransfusion, and postoperatively. Red cell volume (labeling erythrocytes with fluorescein) was determined before and after ANH and postoperatively. RESULTS: Mean normal plasma volumes (1,514 +/- 143 ml/m2) and reduced red cell volumes (707 +/- 79 ml/m2) were measured preoperatively. Blood (1,150 +/- 196 ml) was removed and replaced with 1,333 +/- 204 ml of colloid. Blood volume before and after ANH was equal and amounted to 3,740 ml. Intraoperatively, plasma volume did not increase until retransfusion despite infusing 3,389 +/- 1,021 ml of crystalloid (corrected for urine output) to compensate for an estimated surgical blood loss of 727 +/- 726 mi. Postoperatively, after retransfusion of all autologous blood, blood volume was 255 +/- 424 ml higher than preoperatively before ANH. Despite mean calculated blood loss of 1,256 +/- 892 ml, only one patient received allogeneic blood. CONCLUSIONS: During ANH, normovolemia was exactly maintained. After surgical blood loss of 1,256 +/- 892 ml, crystalloid and colloid supplies of 5,752 +/- 1,462 ml and 1,667 +/- 548 ml, respectively, and complete intraoperative retransfusions of autologous blood in every patient, mean blood volume was 250 ml higher than preoperatively before ANH.

Adult↗
PubMed2000

Acid-base changes caused by 5% albumin versus 6% hydroxyethyl starch solution in patients undergoing acute normovolemic hemodilution: a randomized prospective study.

BACKGROUND: Preoperative acute normovolemic hemodilution (ANH) is an excellent model for evaluating the effects of different colloid solutions that are free of bicarbonate but have large chloride concentrations on acid-base equilibrium. METHODS: In 20 patients undergoing gynecologic surgery, ANH to a hematocrit of 22% was performed. Two groups of 10 patients each were randomly assigned to receive either 5% albumin or 6% hydroxyethyl starch solutions containing chloride concentrations of 150 and 154 mm, respectively, during ANH. Blood volume (double label measurement of plasma and red cell volumes), pH, Paco2, and serum concentrations of sodium, potassium, chloride, lactate, ionized calcium, phosphate, albumin, and total protein were measured before and 20 min after completion of ANH. Strong ion difference was calculated as serum sodium plus serum potassium minus serum chloride minus serum lactate. The amount of weak plasma acid was calculated using a computer program. RESULTS: After ANH, blood volume was well maintained in both groups. ANH caused slight metabolic acidosis with hyperchloremia and a concomitant decrease in strong ion difference. Plasma albumin concentration decreased after hemodilution with 6% hydroxyethyl starch solution and increased after hemodilution with 5% albumin solution. Despite a three-times larger decrease in strong ion difference after ANH with 6% hydroxyethyl starch solution, the decrease in pH was nearly the same in both groups. CONCLUSIONS: ANH with 5% albumin or 6% hydroxyethyl starch solutions led to metabolic acidosis. A dilution of extracellular bicarbonate or changes in strong ion difference and albumin concentration offer explanations for this type of acidosis.

Acid-Base Equilibrium↗
PubMed1998

Group A streptococcal toxic shock syndrome with severe necrotizing fasciitis following hysterectomy--a case report.

In the last 10 years an increasing number of cases of group A streptococcal toxic shock syndrome have appeared in various clinical settings. The manifestation of this syndrome includes rapidly progressive multiorgan failure and soft-tissue necrosis. This report presents a case of streptococcal toxic shock syndrome caused by Streptococcus pyogenes with severe necrotizing fasciitis of the abdominal wall following hysterectomy. Aggressive surgical intervention with debridement of all necrotic tissue necessitated resection of the complete abdominal wall (skin, subcutaneous tissue, muscle and peritoneum). The abdominal wall defect was covered with free myocutaneous flaps and split-skin grafts. Optimal treatment, including adequate antibiotic therapy and radical surgical intervention, is an indispensable prerequisite of successful outcome.

Fasciitis, Necrotizing↗
PubMed1998

First clinical implications of perioperative red cell volume measurement with a nonradioactive marker (sodium fluorescein).

UNLABELLED: We measured red cell volume (RCV) with the nonradioactive marker sodium fluorescein (SoF) in 30 patients undergoing gynecological operations. Sixteen patients underwent preoperative isovolemic hemodilution (PIHD). RCV measurements were performed before and after PIHD and at the end of the operation. All RCVs were related to corresponding hematocrit (hct) levels. We report a simplified method for its clinical application by reducing the number of blood samples required. To validate our method, we compared RCV within the PIHD bags (bag RCV) with the difference of the patients' RCV before and after PIHD. Bag RCV obtained during PIHD (mean 399+/-81 mL) was measured with a precision of 4.2% by using SoF. There was a significant difference (mean 286+/-401 mL; P < 0.05) between intraoperatively estimated and measured blood loss. The blood loss tended to be underestimated and, in some cases, was underestimated or overestimated substantially. Preoperative and postoperative hct values only offered an imprecise estimation of the patients' RCV. We conclude that RCV measurement using SoF is a precise method for monitoring changes in RCV during PIHD and surgical operation. IMPLICATIONS: We measured red cell volume changes of 30 patients with the nonradioactive marker sodium fluorescein before and after hemodilution and postoperatively with a high precision. We frequently found large differences between intraoperatively estimated and measured blood loss. Preoperative hematocrit values offered an imprecise estimation of the patients' red cell volume.

Adult↗
PubMed1998

Effects of adenosine on cardiopulmonary functions and oxygen-derived variables during endotoxemia.

OBJECTIVES: To determine the effects of a prophylactic intravenous infusion of adenosine on cardiopulmonary functions and oxygen-derived variables in a porcine model of endotoxemia. DESIGN: Prospective, randomized, placebo-controlled, unblinded study. SETTING: University research laboratory. SUBJECTS: Thirty country bred pigs, aged 6 to 7 wks, weighing 24.9 +/- 0.65 (SEM) kg body weight. INTERVENTIONS: Pigs were anesthetized by i.v. pentobarbital and fentanyl, intratracheally intubated, and mechanically normoventilated with a gas mixture of nitrous oxide/oxygen = 1:1. Intravascular catheters were inserted to allow for determination of arterial, central venous blood pressure, pulmonary artery occlusion pressure, cardiac output, and sampling of blood for gas analyses. Group 1 (n = 10) received a 330-min intravenous infusion of Salmonella abortus equi endotoxin (5 microg/kg body weight x hr). Group 2 (n = 10) received an additional intravenous infusion of adenosine (150 microg/kg body weight x min), started 30 mins before the infusion of endotoxin. Control groups 3 and 4 (n = 5 for both groups) received adenosine or physiologic saline, respectively. MEASUREMENTS AND MAIN RESULTS: Parameters of cardiopulmonary function and oxygen-derived variables were calculated from pulmonary artery catheter measurements and blood gas analyses using standard formula. Plasma concentrations of purine compounds (adenosine, inosine, hypoxanthine) were determined by high-performance liquid chromatography. Since tumor necrosis factor-alpha plays a central role in the development of endotoxic shock, concentrations of this cytokine were determined in serum by enzyme-linked immunosorbent assay. Infusion of adenosine before the beginning of the infusion of endotoxin increased plasma concentrations of the nucleoside from 193 +/- 72 to 553 +/- 65 nmol/L and decreased the systemic vascular resistance by 50%. Although acting as a potent vasodilator under control conditions, adenosine did not aggravate the arterial hypotension elicited by endotoxemia but significantly increased cardiac output by a comparably small decrease in systemic vascular resistance, prevention of pulmonary vasoconstriction, and improvement of left ventricular performance. Despite significant pulmonary vasodilation, gas exchange was not worsened but slightly improved by adenosine. With the increase in cardiac output and arterial oxygenation, systemic oxygen delivery almost doubled. This adenosine-induced oxygen flux was not a surplus but was most likely utilized by tissues, as suggested by the much earlier beginning of the increase in the systemic oxygen consumption and the attenuation of the decrease in the gastric mucosal pHi. No effects of adenosine were observed on the endotoxin-induced increase in serum concentrations of tumor necrosis factor-alpha. CONCLUSIONS: Infusion of adenosine might be useful to improve flow-dependent oxygen delivery and tissue oxygenation during endotoxic shock without the induction of adverse cardiopulmonary side effects. The beneficial hemodynamic effects of adenosine appear not to be mediated by the inhibition of the release of tumor necrosis factor-alpha.

Adenosine↗
PubMed1998

Buflomedil hydrochloride reduces systemic activation of polymorphonuclear leukocytes during hyperdynamic endotoxemia.

The purpose of the study was to examine the effects of buflomedil hydrochloride (BFL) on the expression of adhesion molecules (beta2-integrins) and oxygen radical production of circulating and emigrated intra-abdominal polymorphonuclear leukocytes (PMNL) in a standardized porcine model of hyperdynamic endotoxemia. A total of 20 anesthetized pigs were randomly assigned to one of the following groups: endotoxin group (endotoxin 5 microg / kg x h, intravenously (i.v.), n = 7), BFL group (BFL (3 mg/kg initial i.v. bolus followed by a continuous infusion (.1 mg / kg x h) and endotoxin 5 microg / kg x h, i.v., n = 7), and control group (NaCl .9%; n = 6). Experiments were terminated at 330 min. Infusion of endotoxin alone resulted in the activation of circulating and emigrated PMNL as evidenced by neutropenia, functional and numerical up-regulation of beta2-integrins, and enhanced oxygen radical production. BFL was able to attenuate functional and numerical up-regulation of beta2-integrins as well as oxygen radical production of circulating and emigrated PMNL. An unexpected decrease in the plasma concentration of BFL during the experiments was associated with an increase in the oxygen radical production of PMNL at the end of the experiments. In addition, BFL attenuated the fall in the intramucosal pH and the increase in plasma concentration of lactate observed in the late phase of endotoxemia. These findings suggest that BFL is able to decrease systemic activation of PMNL and to improve local tissue oxygenation during endotoxemia.

Animals↗