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Biomedical subjects

Joachim Boldt

Publications and source records attributed to Joachim Boldt.

At least 19 recordsLinked to original sources
PubMed2006

Noninvasive assessment of cardiac output using thoracic electrical bioimpedance in hemodynamically stable and unstable patients after cardiac surgery: a comparison with pulmonary artery thermodilution.

OBJECTIVE: To compare noninvasive cardiac output (CO)measurement obtained with a new thoracic electrical bioimpedance (TEB) device, using a proprietary modification of the impedance equation, with invasive measurement obtained via pulmonary artery thermodilution. DESIGN: Prospective, observational study. SETTING: Surgical intensive care unit (ICU) of a university-affiliated community hospital. PATIENTS AND PARTICIPANTS: Seventy-four adult patients undergoing elective cardiac surgery with routine pulmonary artery catheter placement. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Simultaneous paired CO and cardiac index (CI) measurements by TEB and thermodilution were obtained in mechanically ventilated patients upon admission to the ICU. For analysis of CI data the patients were subdivided into a hemodynamically stable group and a hemodynamically unstable group. The groups were analyzed using linear regression and tests of bias and precision. We found a significant correlation between thermodilution and TEB (r = 0.83; n < 0.001), accompanied by a bias of -0.01 l/min/m(2) and a precision of +/-0.57 l/min/m(2) for all CI data pairs. Correlation, bias, and precision were not influenced by stratification of the data. The correlation coefficient, bias, and precision for CI were 0.86 (n< 0.001), 0.03 l/min/m(2), and +/-0.47 l/min/m(2) in hemodynamically stable patients and 0.79 (n< 0.001), 0.06 l/min/m(2), and +/-0.68 l/min/m(2) in hemodynamically unstable patients. CONCLUSIONS: Our results demonstrate a close correlation and clinically acceptable agreement and precision between CO measurements obtained with impedance cardiography using a new algorithm to calculate CO from variations in TEB, and those obtained with the clinical standard of care, pulmonary artery thermodilution, in hemodynamically stable and unstable patients after cardiac surgery.

Aged↗
PubMed2006

Do plasma substitutes have additional properties beyond correcting volume deficits?

The best strategy for volume therapy has been the focus of debate and there are still no unique accepted guidelines. There is increasing evidence that some plasma substitutes possess additional effects on organ perfusion, microcirculation, tissue oxygenation, inflammation, endothelial activation, capillary leakage, and tissue edema that are beyond their volume replacing properties. Whether the different plasma substitutes differ with regard this additional effects was reviewed. The additional effects of plasma substitutes have mostly been studied experimentally or in animals, much less results are available in humans. The results are not uniform ranging from beneficial to even detrimental effects of a certain volume replacement strategy. Some important results from the literature are not reflected in the actual recommendations for treating volume deficits in the critically ill: although crystalloids have been shown to have considerable negative effects on microcirculation, organ perfusion, tissue oxygenation, and endothelial integrity, they are still often recommended as first choice volume replacement strategy. In several experimental studies hypertonic solutions have been shown to have various beneficial effects, they have not been, however, translated into humans. In future, the choice of the ideal volume replacement regimen should not only be focused on its volume restoring properties, but additional effects (e.g. on organ perfusion on, tissue oxygenation, inflammation, endothelial activation, capillary leakage) should also be taken into account when treating hypovolemia in the critically ill.

Animals↗
PubMed2006

Desflurane anesthesia after sevoflurane inhaled induction reduces severity of emergence agitation in children undergoing minor ear-nose-throat surgery compared with sevoflurane induction and maintenance.

Emergence agitation may occur after general anesthesia with volatile anesthetics in children. We designed this study to examine the emergence behavior of children undergoing ear-nose-throat surgery after sevoflurane induction and desflurane maintenance versus both sevoflurane induction and maintenance using a recently published Pediatric Anesthesia Emergence Delirium (PAED) scale. In 38 premedicated children aged 12 mo to 7 yr mask induction with sevoflurane was performed and they were randomly assigned to receive either sevoflurane (n = 19) or desflurane (n = 19) for maintenance of general anesthesia. Time to tracheal extubation, modified Aldrete score, emergence behavior, recovery complications, and pain scores were assessed. The PAED scale showed a significant advantage for desflurane (6 [0-15] versus 12 [2-20], maximum total score of 20 for severe agitation). Time to extubation was significantly shorter with desflurane than with sevoflurane (5.4 +/- 1.4 versus 13.4 +/- 1.8 min). The modified Aldrete score on arrival in the postanesthesia care unit (PACU) was significantly lower in children receiving sevoflurane for maintenance. Time to discharge from PACU to normal ward and the incidence of adverse effects were not significantly different between the groups. In conclusion, the use of desflurane for maintenance of anesthesia after sevoflurane induction in children is associated with less severe emergence agitation and faster emergence times.

Anesthesia Recovery Period↗
PubMed2006

The value of an albumin-based intravascular volume replacement strategy in elderly patients undergoing major abdominal surgery.

The value of human albumin (HA) for treating hypovolemia is controversial. Less expensive alternatives such as hydroxyethyl starch (HES) are sometimes refused because of unwanted side effects. We prospectively randomized 50 patients older than 70 years old undergoing major abdominal surgery to receive either 5% HA (n = 25) or a third generation HES preparation (6% HES 130/0.4; n = 25) when mean arterial blood pressure was <60 mm Hg and central venous pressure was <10 mm Hg. Hemodynamics, inflammation (interleukin-6), endothelial activation-integrity (adhesion molecules), coagulation (thrombelastography), and renal function (including kidney-specific proteins) were monitored after the induction of anesthesia, after surgery, 5 h in the intensive care unit, and on the first postoperative day. HA patients received 3960 +/- 590 mL of HA and 5070 +/- 1030 mL of Ringer's lactate solution, and HES patients received 3500 +/- 530 mL of HES and 4550 +/- 880 mL of Ringer's lactate solution. Total protein remained normal only in the HA-treated patients. No significant differences (P > 0.1) between the groups were seen with regard to hemodynamics, coagulation, and kidney function. Plasma levels of interleukin-6 and soluble adhesion molecules were significantly (P < 0.05) higher in the HA- than in the HES-treated patients. We conclude that HA in elderly patients undergoing major abdominal surgery can easily be replaced by a modern HES preparation. Because of the decreased inflammatory response and endothelial activation-injury, HES 130/0.4 seems to be the more appropriate fluid strategy for these patients.

Abdomen↗
PubMed2006

Total intravenous anesthesia with propofol and remifentanil is associated with a nearly twofold higher incidence in postanesthetic shivering than desflurane-fentanyl anesthesia.

BACKGROUND: Postanesthetic shivering (PAS) is a frequent side effect of general anesthesia. Previous reports on the incidence of PAS of propofol for the induction or maintenance of anesthesia have been controversial, but have not been studied in detail. The aim of the present study was to evaluate the incidence and severity of PAS in total intravenous anesthesia (TIVA) with propofol and remifentanil compared with an inhalative anesthesia. MATERIAL/METHODS: After ethics committee approval and written informed consent from the patients, 53 patients scheduled for urologic, gynecologic, or surgical operations were studied for shivering postoperatively using a five-point rating scale. They received desflurane-fentanyl based anesthesia (n=27) or TIVA with propofol and remifentanil (n=26). Hemodynamics and temperature were measured after induction of anesthesia (T0), and 5 min (T1), 15 min (T2), 30 min (T3), and 60 min (T4) after reaching the postanesthetic care unit (PACU). RESULTS: In the TIVA group, 18/26 (69.2%) patients suffered from PAS compared with 10/27 (37%) in the desflurane-fentanyl group (P<0.02). The severity of shivering was significantly higher with TIVA than with desflurane (P<0.02), whereas temperature showed no significant difference between the study groups. CONCLUSIONS: Postanesthetic shivering appears significantly more frequently and intensively after TIVA with propofol and remifentanil compared with an inhalative anesthesia with fentanyl and desflurane.

Aged↗
PubMed2005

Advanced sternal closure to prevent dehiscence in obese patients.

Sternal dehiscence is a frequent complication after cardiac surgical procedures. The objective was to evaluate a novel method for advanced sternal closure compared with standard techniques for preventing sternal dehiscence. Our investigation comprised 100 patients with a body mass index above 32. Patients were randomly assigned to receive either advanced sternal closure with three stainless steel double wires or standard techniques with stainless steel single wires. The incidence of sternal refixation was 6 of 50 patients in the standard techniques group and 1 of 50 in the advanced sternal closure group during a follow-up period of 6 months.

Aged↗
PubMed2005

Continuous intra- and postoperative thoracic epidural analgesia attenuates brain natriuretic peptide release after major abdominal surgery.

We investigated whether blocking afferent nociceptive inputs by continuous intra- and postoperative thoracic epidural analgesia (TEA) would decrease plasma concentrations of brain natriuretic peptide (BNP) in patients who were at risk for, or had, coronary artery disease. Twenty-eight patients undergoing major abdominal surgery received either general anesthesia supplemented with a continuous thoracic epidural infusion of 1.25 mg/mL bupivacaine and 1 microg/mL sufentanil (n = 14; TEA) or general anesthesia followed by IV patient-controlled analgesia (n = 14; IV PCA). Visual analog scale pain scores, hemodynamics, plasma catecholamines, cardiac troponin T, atrial natriuretic peptide (ANP), and BNP were serially measured preoperatively, 90 min after skin incision, at arrival in the intensive care unit, and in the morning of the first, second, and third postoperative day. Dynamic visual analog scale scores were significantly less in the TEA group. TEA reduced the postoperative heart rate without affecting other hemodynamic variables. Plasma epinephrine increased perioperatively in both groups but was significantly lower in the TEA group. Baseline ANP and BNP concentrations were similar between groups (TEA 3.4 +/- 1.8 and 27.0 +/- 12.3 pg/mL; IV PCA 3.1 +/- 2.0 and 25.9 +/- 13.0 pg/mL, respectively). ANP and BNP increased perioperatively in both groups, with significantly lower postoperative BNP levels in TEA patients (TEA 92.1 +/- 31.9 pg/mL; IV PCA 161.2 +/- 44.7 pg/mL). No such difference was observed in plasma ANP concentrations. Plasma cardiac troponin T concentrations were within normal limits in both groups at all times. We conclude that continuous perioperative TEA using local anesthetics and opioids attenuated the release of BNP in patients undergoing major abdominal surgery who were at risk for, or had, coronary artery disease.

Abdomen↗
PubMed2004

Levosimendan in patients with cardiogenic shock undergoing surgical revascularization: a case series.

BACKGROUND: Levosimendan is a new calcium sensitizer, which enhances myocardial contractility while simultaneously having vasodilatory and cardioprotective effects. These properties could be advantageous in patients with myocardial ischemia requiring inotropic support. MATERIAL/METHODS: 10 patients with acute myocardial ischemia, cardiogenic shock, and/or cardiopulmonary resuscitation undergoing emergency surgical revascularization were treated with levosimendan (bolus 6 microg.kg(-1), continuous infusion 0.2 microg.kg(-1).min(-1)) in addition to catecholamines. RESULTS: All patients treated with levosimendan and catecholamines were weaned successfully from CPB on the 1st attempt. All patients needed additional norepinephrine because of vasodilation. In 4 patients, levosimendan was stopped in the early postoperative period. 2 patients died, 8 patients survived without any multiorgan failure. Only 2 patients needed an additional intra-aortic balloon pump. In the surviving patients, postoperative ventilation lasted for 8-72 hours. CONCLUSIONS: Levosimendan may have exerted positive inotropic and cardioprotective effects in these high risk patients with acute myocardial ischemia. However, these preliminary results supporting the use of levosimendan as an inoprotective drug need to be confirmed by a large randomized prospective trial.

Adult↗
PubMed2004

[Hydroxyethylstarch (HES)].

Adequate volume replacement therapy is a mainstay of managing the critically ill. The ideal kind of volume replacement in this situation still remains a challenge. In spite of an immense number of contributions to this problem there is still no definite answer. The ideal volume replacement strategy should not only aim at maintaining stable systemic hemodynamics, organ perfusion and microcirculation should be guaranteed or even improved as well. Due to its excellent efficacy, hydroxyethylstarch (HES) preparations are widely used to treat hypovolemia. The different physico-chemical properties of the available HES solutions, however, should be taken into account. Anphylactoid reactions as well as negative effects on coagulation, kidney/liver function and on the immune system are frequently used arguments against the administration of HES, but they can virtually be neglected when using modern HES preparations to correct hypovolemia. There are, however, still open questions concerning the use of HES in children, pregnant patients, patients with altered kidney function and in burn patients.

Anaphylaxis↗
PubMed2004

Influence of different volume replacement strategies on inflammation and endothelial activation in the elderly undergoing major abdominal surgery.

OBJECTIVE: Adequate restoration of intravascular volume remains an important maneuver in the management of the surgical patient. Influence of different volume replacement regimens on inflammation/endothelial activation in elderly surgical patients was assessed. DESIGN: Prospective, randomized study. SETTING: Surgical intensive care unit of a university-affiliated hospital. PATIENTS: Sixty-six patients >65 years undergoing major abdominal surgery. INTERVENTIONS: Ringer's lactate (RL; n=22), normal saline solution (NS; n=22) or a low-molecular HES (mean molecular weight 130 kD) with a low degree of substitution (0.4; HES 130/0.4; n=22) were administered after induction of anesthesia until the 1st postoperative day (POD) to keep central venous pressure between 8-12 mmHg. MEASUREMENTS AND RESULTS: C-reactive protein, interleukins (IL-6, IL-8), adhesion molecules [endothelial leukocyte adhesion molecule-1 (ELAM-1) and intercellular adhesion molecule-1 (ICAM-1)] were measured prior to volume therapy at the end of surgery, 5 h after surgery and at the morning of the 1st POD. RL patients received 10,150+/-1,660 ml of RL, NS patients 10,220+/-1,770 ml of NS and the HES-treated group 2,850+/-300 ml of HES 130/0.4 and 2,810+/-350 ml of RL. Hemodynamics were similar in all groups. CRP, IL-6 and IL-8 plasma levels increased significantly higher in both crystalloid groups (IL-6 in the NS group: increase to 407+/-33 pg/ml; RL: increase to 377+/-35 pg/dl) than in the HES-130 treated group (IL-6: increase to 197+/-20 pg/dl). Plasma levels of ELAM-1 and ICAM remained almost unchanged in the HES 130-, but significantly increased in the RL- and NS-treated patients. CONCLUSIONS: In elderly patients, markers of inflammation and endothelial injury and activation were significantly higher after crystalloid- than after HES 130/0.4-based volume replacement regimens.

Abdomen↗
PubMed2004

Fluid choice for resuscitation of the trauma patient: a review of the physiological, pharmacological, and clinical evidence.

PURPOSE: Volume replacement regimens are discussed very emotionally. Interpretation of the literature is difficult due to variations in study design, patient population, target for volume replacement, endpoints, and type of fluids. Meta-analyses may not be very helpful because all kinds of patients and very old studies are included. The principles and options for volume replacement were reviewed exclusively in trauma patients and studies from the literature focusing on this problem were analyzed. SOURCE: Using a MEDLINE search, volume replacement therapy in adult trauma patients published in the English language from 1985 to the end of 2002 were identified and analyzed. Studies on prehospital volume replacement, volume replacement in the emergency area or in the operating room, and volume therapy in trauma intensive care unit patients were included. PRINCIPLE FINDINGS: The age-old crystalloid/colloid controvery has still not been resolved but has been enlarged to a colloid/colloid debate. It is now widely accepted that human albumin could easily be replaced by synthetic colloids for volume replacement in trauma patients. No superiority of a specific volume replacement strategy with regard to outcome was found. However, in several studies outcome was not the major endpoint. Although showing some promising results, the importance of hypertonic solutions for volume replacement in the trauma patient is not yet defined. CONCLUSION: The choice of fluid therapy in trauma patients engenders the most controversy and an examination of the body of literature on this subject results in confusion. It is imperative to continue the search for substances that are effective in avoiding the development of post-trauma multi-organ dysfunction syndrome without detrimental side-effects.

Blood Volume↗
PubMed2004

Natriuretic peptide system: physiology and clinical utility.

PURPOSE OF REVIEW: This review discusses the physiology of natriuretic peptides as a group and brain natriuretic peptide (BNP) in more detail. It will also highlight implications for the use of the natriuretic peptides in the diagnosis and treatment of patients with cardiovascular disease. RECENT FINDINGS: The heart secretes two major natriuretic peptides: atrial natriuretic peptide (ANP), which is synthesized in the atrial myocardium, and BNP, which is synthesized in the ventricular myocardium. Both ANP and BNP are released in response to atrial and ventricular stretch, respectively, and will cause balanced vasodilation, natriuresis, and inhibition of the sympathetic nervous system and the renin-angiotensin-aldosterone axis. BNP is reported to be the biochemical marker of choice for evaluating the acute risk of patients with cardiovascular disease states ranging from heart failure to myocardial ischemia. Increased blood BNP concentrations are highly predictive of the short- and long-term risk of cardiac death across the entire spectrum of acute coronary syndromes and in patients with decompensated congestive heart failure. Synthetic recombinant human BNP, which mimics the actions of endogenous BNP, has emerged as an important new therapeutic agent in patients with acute heart failure. SUMMARY: Current data suggest that single and serial plasma measurement of BNP concentrations is a useful tool in the diagnosis and risk stratification of patients with heart disease. Nesiritide, the human recombinant form of BNP, is a new promising parenteral treatment in decompensated heart failure.

Amino Acid Sequence↗