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Biomedical subjects

Thomas W Felbinger

Publications and source records attributed to Thomas W Felbinger.

18 recordsLinked to original sources
PubMed2005

Cardiac index measurements during rapid preload changes: a comparison of pulmonary artery thermodilution with arterial pulse contour analysis.

STUDY OBJECTIVE: To compare cardiac index (CI) values obtained by pulmonary artery thermodilution (CIPA), arterial thermodilution (CITD), and arterial pulse contour analysis (CIPC) during rapid fluid administration, as accurate and rapid detection of CI changes is critical during acute preload changes for guiding volume and vasopressor therapy in critically ill patients, and the accuracy of CIPC during acute changes in loading condition is currently unknown. DESIGN: Prospective clinical study. SETTING: Cardiac surgical intensive care unit of a university hospital. PATIENTS: Seventeen American Society of Anesthesiologists (ASA) physical status II and III patients, aged 32 to 76 years, with normal left ventricular function during the early postoperative period after elective coronary artery bypass graft surgery. MEASUREMENTS: After baseline determinations of CIPA, CIPC, and CITD were made, fluid loading was performed using 10 mL times body mass index of hydroxyethyl starch 6%. CIPA, CIPC, and CITD were determined, and changes in CI (DeltaCI) were calculated. Fluid load was repeated until no increase in stroke volume index (DeltaSVI <10%) was achieved. MAIN RESULTS: Regression analysis between CIPA/CIPC, CIPA/CITD, and CIPC/CITD revealed r2 = 0.92, r2 = 0.92, and r2 = 0.98. Regression analysis between DeltaCIPA/DeltaCIPC, DeltaCIPA/DeltaCITD, and DeltaCIPC/DeltaCITD revealed r2 = 0.57, r2 = 0.67, and r2 = 0.74, respectively. Bland-Altman analysis was used to determine accuracy and precision of the 3 methods compared. The mean differences (m) and SD between DeltaCIPA/DeltaCIPC, DeltaCIPA/DeltaCITD, and DeltaCIPC/DeltaCITD resulted in m = -1.01%, SD = 6.51%; m = -0.83%, SD = 5.80%; and m = -0.33%, SD = 4.65%, respectively. CONCLUSION: Compared with pulmonary artery thermodilution, arterial pulse contour analysis reflects relative changes in CI during rapid changes of preload with clinically acceptable accuracy.

Adult↗
PubMed2004

CXCL12 mediates CCR7-independent homing of central memory cells, but not naive T cells, in peripheral lymph nodes.

Central memory CD8(+) T cells (T(CM)) confer superior protective immunity against infections compared with other T cell subsets. T(CM) recirculate mainly through secondary lymphoid organs, including peripheral lymph nodes (PLNs). Here, we report that T(CM), unlike naive T cells, can home to PLNs in both a CCR7-dependent and -independent manner. Homing experiments in paucity of lymph node T cells (plt/plt) mice, which do not express CCR7 ligands in secondary lymphoid organs, revealed that T(CM) migrate to PLNs at approximately 20% of wild-type (WT) levels, whereas homing of naive T cells was reduced by 95%. Accordingly, a large fraction of endogenous CD8(+) T cells in plt/plt PLNs displayed a T(CM) phenotype. Intravital microscopy of plt/plt subiliac lymph nodes showed that T(CM) rolled and firmly adhered (sticking) in high endothelial venules (HEVs), whereas naive T cells were incapable of sticking. Sticking of T(CM) in plt/plt HEVs was pertussis toxin sensitive and was blocked by anti-CXCL12 (SDF-1alpha). Anti-CXCL12 also reduced homing of T(CM) to PLNs in WT animals by 20%, indicating a nonredundant role for this chemokine in the presence of physiologic CCR7 agonists. Together, these data distinguish naive T cells from T(CM), whereby only the latter display greater migratory flexibility by virtue of their increased responsiveness to both CCR7 ligands and CXCL12 during homing to PLN.

Animals↗
PubMed2004

Ketamine for long-term sedation and analgesia of a burn patient.

We present a case in which ketamine was used for long-term sedation and analgesia of a burn patient. Under escalating opiate dosages, the patient had developed persistent ileus as well as abdominal distension that caused respiratory compromise, without receiving sufficient analgesia. The opiate-sparing effect of the continuous ketamine infusion was more than 90%. The ileus resolved within 24 h. The quality of sedation also changed favorably. There were no obvious adverse effects of ketamine.

Adult↗
PubMed2003

The clearance mechanism of chilled blood platelets.

Platelet transfusion is a very common lifesaving medical procedure. Not widely known is the fact that platelets, unlike other blood cells, rapidly leave the circulation if refrigerated prior to transfusion. This peculiarity requires blood services to store platelets at room temperature, limiting platelet supplies for clinical needs. Here, we describe the mechanism of this clearance system, a longstanding mystery. Chilling platelets clusters their von Willebrand (vWf) receptors, eliciting recognition of mouse and human platelets by hepatic macrophage complement type 3 (CR3) receptors. CR3-expressing but not CR3-deficient mice exposed to cold rapidly decrease platelet counts. Cooling primes platelets for activation. We propose that platelets are thermosensors, primed at peripheral sites where most injuries occurred throughout evolution. Clearance prevents pathologic thrombosis by primed platelets. Chilled platelets bind vWf and function normally in vitro and ex vivo after transfusion into CR3-deficient mice. Therefore, GPIb modification might permit cold platelet storage.

Animals↗
PubMed2003

Usefulness of left ventricular stroke volume variation to assess fluid responsiveness in patients with reduced cardiac function.

OBJECTIVE: Stroke volume variation as measured by the analysis of the arterial pressure waveform enables prediction of volume responsiveness in ventilated patients with normal cardiac function. The aim of this study was to investigate the ability of monitoring stroke volume variation to predict volume responsiveness and to assess changes in preload in patients with reduced left ventricular function after cardiac surgery. DESIGN: Prospective study. SETTING: University hospital. PATIENTS: Fifteen mechanically ventilated patients with a left ventricular ejection fraction <0.35 (study group) and 15 patients with an ejection fraction >0.50 (control group) after coronary artery bypass grafting following admission to the intensive care unit. INTERVENTIONS: Volume loading with 10 mL of hetastarch 6% times body mass index. If stroke volume index increased >5%, successive volume loading was performed until no further increase in stroke volume index was reached. MEASUREMENTS AND MAIN RESULTS: Stroke volume variation, central venous pressure, pulmonary artery occlusion pressure (PAOP), and left ventricular end-diastolic area index (LVEDAI) were measured at baseline and immediately after each volume loading step. In both groups, stroke volume variation at baseline correlated significantly with changes in stroke volume index caused by volume loading (p <.01). Further, changes in stroke volume variation as a result of volume loading correlated significantly with the concomitant changes in stroke volume index in both groups (p <.01). Using receiver operating characteristic analysis, in the study group areas under the curve for stroke volume variation, PAOP, central venous pressure, and LVEDAI did not differ significantly. In the control group, the area under the curve for stroke volume variation was statistically larger than for PAOP, central venous pressure, and LVEDAI. CONCLUSIONS: Continuous and real-time monitoring of stroke volume variation by pulse contour analysis can predict volume responsiveness and allows real-time assessment of the hemodynamic effect of volume expansion in patients with reduced left ventricular function after cardiac surgery.

Aged↗
PubMed2003

Penetration of intravenous hydroxyethyl starch into the cerebrospinal fluid in patients with impaired blood-brain barrier function.

UNLABELLED: Hypovolemic patients with impairment of the blood-brain barrier may receive IV hydroxyethyl starch (HES) to stabilize cardiovascular function and to increase cerebral perfusion pressure. It is not known whether HES can penetrate into the cerebrospinal fluid (CSF) under those conditions. We investigated plasma and CSF levels of HES after IV infusion in patients with suspected disturbance of the blood-brain barrier. Eight adult patients were studied who were being treated for head trauma or subarachnoid hemorrhage, with an external CSF drain in place. All patients exhibited radiographic signs of blood-brain barrier impairment diagnosed by cerebral computed tomography. After IV infusion of 500 to 1000 mL of HES 200,000/0.5, plasma HES levels were measured. Additionally, all CSF that was drained within 8 h after the HES infusion was collected, and HES concentrations were measured. All patients had detectable HES plasma concentrations (3.41 to 9.95 mg/mL). In contrast, no HES could be detected in the CSF of any patient. These data indicate that IV HES 200,000/0.5 does not penetrate into the CSF in patients with disturbed blood-brain barrier function after subarachnoid hemorrhage or head trauma. Further study is required to determine whether HES penetrates into the intracranial interstitium, despite the absence of HES in the CSF. IMPLICATIONS: Patients may receive IV hydroxyethyl starch (HES) after head trauma or subarachnoid hemorrhage. The results of the present study indicate that in patients with suspected blood-brain barrier impairment, HES does not penetrate from the plasma into the cerebrospinal fluid.

Adult↗
PubMed2002

Stroke volume variations for assessment of cardiac responsiveness to volume loading in mechanically ventilated patients after cardiac surgery.

OBJECTIVE: We hypothesized that measuring stroke volume variation (SVV) during mechanical ventilation by continuous arterial pulse contour analysis allows the accurate prediction and monitoring of changes in cardiac index (CI) in response to volume administration. DESIGN AND SETTING: Prospective study in an university hospital. PATIENTS: Twenty mechanically ventilated patients following cardiac surgery. INTERVENTIONS: Volume loading with oxypolygelatin (3.5%) 20 ml x body mass index over 10 min. MEASUREMENTS AND RESULTS: SVV, central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP), left ventricular end-diastolic area index (LVEDAI) by transesophageal echocardiography, intrathoracic blood volume index (ITBVI) by transpulmonary thermodilution and CI were determined immediately before and after volume loading. SVV decreased, while CI, CVP, PAOP, ITBVI, and LVEDAI increased significantly. Percentage changes in CI were significantly correlated to percentage changes in SVV (r(2)=-0.59, p<0.001), ITBVI (r(2)=0.79, p<0.001), and PAOP (r(2)=0.33, p<0.05) and to baseline values of SVV (r(2)=0.55, p<0.05) and LVEDAI (r(2)=-0.68, p<0.001). CONCLUSIONS: SVV may help to determine the preload condition of ventilated patients following cardiac surgery and to predict and continuously monitor effects of volume administered as part of their hemodynamic management.

Aged↗
PubMed2002

Comparison of pulmonary arterial thermodilution and arterial pulse contour analysis: evaluation of a new algorithm.

STUDY OBJECTIVE: To compare cardiac index (CI) measurement by arterial pulse contour analysis using two different algorithms (CI(PC), CI(PCnew)) with pulmonary arterial thermodilution values (CI(PA)) so as to evaluate the difference between the conventional algorithm, CI(PC), and a new algorithm, CI(PCnew), that accounts for patients' individual aortic compliance. DESIGN: Prospective, clinical study. SETTING: Intensive care unit of a university hospital. PATIENTS: 20 ASA physical status II and III patients following elective cardiac surgery. MEASUREMENTS AND MAIN RESULTS: 360 parallel triplicate determinations of CI (CI(PA), CI(PC), CI(PCnew)) were performed within a 90-minute period during the immediate postoperative period. Prior to the start of the study period, CI(PC) as well as CI(PCnew) were calibrated by triplicate femoral arterial thermodilution measurements. Regression analysis of CI(PA) and CI(PC), as well as CI(PA) and CI(PCnew), revealed r = 0.89, p < 0.001, and r = 0.93, p < 0.001, respectively. Bland-Altman analysis was used for determining the accuracy and precision of CI(PC) and CI(PCnew) compared with CI(PA). The mean differences (m) and standard deviation (SD) between CI(PA) and CI(PC,) as well as CI(PA) and CI(PCnew), resulted in m = -0.312 L/min/m(2), SD = 0.456 L/min/m(2), and m = - 0.140 L/min/m(2), SD = 0.328 L/min/m(2), respectively. CONCLUSION: Arterial pulse contour analysis measurement of CI using either algorithm correlates well with CI values derived by pulmonary arterial thermodilution. However, the algorithm introduced in this study proved to be a more accurate predictor of values as derived by pulmonary artery catheter.

Algorithms↗
PubMed2002

Intrathoracic blood volume index measured by thermodilution for preload monitoring after cardiac surgery.

OBJECTIVE: To investigate the accuracy of measurement of intrathoracic blood volume index by single thermodilution (ITBVI*) and its sensitivity to detect changes in preload after cardiac surgery compared with conventional transpulmonary arterial dye dilution ITBVI and with conventional monitoring (central venous pressure [CVP] and left ventricular end-diastolic area index [EDAI] by transesophageal echocardiography). DESIGN: Prospective clinical study. SETTING: University hospital. PARTICIPANTS: Nineteen patients immediately after cardiac surgery. INTERVENTIONS: Volume loading was administered with 20 mL of oxypoligelatine (Haemaccel [Behringwerke Aktiengesellschaft Corp, Marburg, Germany]) 3.5% times body mass index over 10 minutes. MEASUREMENTS AND MAIN RESULTS: Intrathoracic blood volume index was measured by dye dilution (ITBVI) and thermodilution (ITBVI*) immediately before and after volume loading. Measurements of ITBVI and ITBVI* correlated closely (r = 0.94; p < 0.0001). With volume loading, ITBVI and ITBVI* increased significantly from 877 +/- 195 mL/m(2) to 967 +/- 180 mL/m(2) and from 889 +/- 195 mL/m(2) to 954 +/- 185 mL/m(2). Percent changes in ITBVI (deltaITBVI) and ITBVI* (deltaITBVI*) did not differ significantly and correlated closely (r = 0.90; p < 0.0001). Percent changes in cardiac index (CI) as a result of volume loading (deltaCI) revealed significant correlation to deltaITBVI (r = 0.85; p < 0.0001) and to deltaITBVI* (r = 0.76; p < 0.0005). No significant correlation could be found between deltaCI and deltaEDAI or deltaCVP. CONCLUSION: In patients undergoing cardiac surgery, determination of ITBVI* revealed close agreement with measurements derived by ITBVI. Enhancement in cardiac preload was adequately detected by ITBVI*.

Blood Volume↗
PubMed2002

The effect of remifentanil or fentanyl on postoperative vomiting and pain in children undergoing strabismus surgery.

UNLABELLED: Postoperative vomiting (POV) after strabismus surgery in children results in discomfort and prolonged hospital stays. Opioids increase the incidence of POV. Remifentanil has a context-sensitive half-life of 3 to 4 min, and how this short half-life influences POV in those patients is unknown. We conducted a prospective, double-blinded study in 81 ASA status I or II children from 2 to 12 yr of age undergoing elective strabismus surgery under general anesthesia. Patients were randomized to receive either remifentanil (bolus 1 microg/kg; infusion 0.1-0.2 microg x kg(-1) x min(-1)) or fentanyl (2 microg/kg, and 1 microg/kg every 45 min). POV episodes were recorded for 25 h. Pain scores were obtained by using an objective pain scale for 60 min during recovery. The number of patients who experienced POV did not differ significantly between groups (49% vs 48%). However, in the Remifentanil group, POV episodes were significantly less frequent (0.95 vs 2.2 episodes). In contrast, fentanyl was associated with lower pain scores during the first 30 min of recovery. We conclude that children undergoing strabismus surgery under balanced anesthesia with remifentanil, compared with fentanyl, showed less frequent POV. However, early postoperative analgesia was better with fentanyl. IMPLICATIONS: Opioids increase the incidence of postoperative vomiting (POV). Remifentanil is characterized by the shortest half-life of all opioids used in anesthetic practice. Therefore, we studied the effect of remifentanil on POV compared with the longer-acting opioid fentanyl in children undergoing strabismus surgery.

Analgesics, Opioid↗
PubMedDate not supplied

ICAM-1 and beta2 integrin deficiency impairs fat oxidation and insulin metabolism during fasting.

Intercellular adhesion molecule 1 (ICAM-1) and beta2 integrins play critical roles in immune responses. ICAM-1 may also participate in regulation of energy balance because ICAM-1-deficient mice become obese on a high-fat diet. We show that mice deficient in these adhesion receptors are unable to respond to fasting by up-regulation of fatty acid oxidation. Normal mice, when fasted, exhibit reduced circulating neutrophil counts and increased ICAM-1 expression and neutrophil recruitment in liver. Mice lacking ICAM-1 or beta2 integrins fail to show these responses--instead they become hypoglycemic with steatotic livers. Fasting ICAM-1-deficient mice reduce insulin more slowly than wild-type mice. This produces fasting hyperinsulinemia that prevents activation of adenosine mono-phosphate (AMP)-activated protein kinase in muscles and liver, which results in decreased import of long chain fatty acids into mitochondria. Thus, we show a new role for immune cells and their adhesion receptors in regulating metabolic response to fasting.

Animals↗