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Biomedical subjects

K F Klotz

Publications and source records attributed to K F Klotz.

At least 19 recordsLinked to original sources
PubMed2006

The Na+/H+ exchange inhibitor cariporide is washed out of the myocardium by crystalloid cardioplegia.

BACKGROUND: Inhibition of the Na (+)/H (+) exchanger (NHE) is cardioprotective, but dosage and timing of NHE-inhibitors are critical for their efficacy. We studied the effect of a new dosing regime of the NHE-inhibitor cariporide on myocardial function and damage after cardioplegic arrest (CPA) and determined its myocardial and serum concentrations. METHODS: 3 pigs received a bolus of 180 mg cariporide intravenously (i. v.) and were sacrificed shortly thereafter to allow measurement of the myocardial concentrations of cariporide. Subsequently, 10 pigs were randomized to receive either i. v. cariporide (bolus followed by an infusion of 40 mg/h) or placebo. Cardiopulmonary bypass was initiated, and the heart was arrested for 60 minutes by infusion of St. Thomas Hospital solution. Left ventricular (LV) function was studied using microsonometry. Myocardial damage was assessed by troponin T. Serum concentrations of cariporide were measured throughout the study, and myocardial concentrations were measured before the end of CPA and 180 minutes thereafter. RESULTS: Cariporide was present in all myocardial specimens (median: 1.4 ng/mg) studied previously. In the main study, LV function or myocardial damage did not differ significantly between the groups at any time point. Stable serum cariporide concentrations were achieved (3.4 +/- 0.5 microg/ml). Cariporide was detectable in only one of the myocardial biopsies obtained before the end of CPA, but 180 minutes thereafter, the myocardial cariporide concentration was 2.5 +/- 0.3 ng/mg. CONCLUSION: We observed no effect of i. v. cariporide on LV function or myocardial damage after cardioplegic arrest. Our data suggest that cariporide is washed out of the myocardium by repeated application of crystalloid cardioplegia. Thus, the mode of delivery also appears to be critical for cardioprotection with NHE-inhibitors.

Analysis of Variance↗
PubMed2004

Detection of causal relationships between factors influencing adverse side-effects from anaesthesia and convalescence following surgery: a path analytical approach.

BACKGROUND AND OBJECTIVE: The anaesthesiologist's preoperative interview with the patient is important in preparing the patient for surgery. Its potential protective influence on adverse side-effects from anaesthesia and convalescence is rarely investigated within the context of other perioperative factors. Structural equation modelling allows detection and quantification of all causal relationships and mediator effects in multivariate models. Therefore, this method is presented as a tool and applied to discover the influence of the preoperative interview within socio-demographic variables and duration of surgery on complaints and recovery after anaesthesia. METHODS: The influence of individual satisfaction with the anaesthesiologist's preoperative interview on postoperative events such as nausea/vomiting, difficulties in recovering from anaesthesia, experience of postoperative pain, physical discomfort and satisfaction with convalescence expressed by the patient was analysed by means of structural equation modelling. The variables gender, age and duration of surgery were also included as predictors in the analyses. The model in the total sample of 710 patients was then analysed for structural differences between groups treated either with propofol (n = 204) or with isoflurane + nitrous oxide (n = 267) for maintenance of anaesthesia. RESULTS: The model revealed that the anaesthesiologist's preoperative interview in combination with associated mediating side-effects explains 45% of the variance of 'feeling physical discomfort' and 18% of the variance of 'satisfaction with convalescence'. The same model could be fitted in the propofol and the isoflurane + nitrous oxide group. Moreover, the structure and the strength of causal relations between variables were identical in the two groups. CONCLUSIONS: The anaesthesiologist's efforts to improve the interview with the patient by more reassuring and proper information will result in less side-effects from anaesthesia and better recovery from surgery. It could be demonstrated that structural equation modelling is a powerful tool for detection of causal relationships and mediator effects in perioperative medicine.

Adolescent↗
PubMed2001

The effect of moderate hypovolaemia on microcirculation in healthy older blood donors.

Compensation for acute blood loss requires cardiovascular integrity. In older people, asymptomatic cardiovascular impairment is common. In these subjects, even moderate blood loss is often treated by external volume replacement although its benefits are not clear. We investigated the effect of 450 ml of blood loss on the microcirculation and compensatory mechanisms in healthy older blood donors. Red blood cell count, plasma viscosity and protein concentration were measured. Plasma volume replacement was calculated using haematocrit. We measured microcirculation tissue perfusion by laser Doppler fluxmetry prior to, during and after blood donation. Blood loss was immediately accompanied by a median rapid water shift of 208 ml (interquartile range 134-298 ml). Haemodilution led to a decrease in haematocrit, protein and plasma viscosity. We observed no changes in cutaneous microcirculation. Moderate blood loss is tolerated in older cardiovascularly asymptomatic patients without having an impact on microcirculation. This may reduce the need for external volume replacement.

Aged↗
PubMed2001

Effects of isoflurane, enflurane, and halothane on skeletal muscle microcirculation in the endotoxemic rat.

PURPOSE: The cardiovascular effects of volatile anesthetics during sepsis sets patients at high risk for hemodynamic deterioration. We compared the microcirculatory alterations in skeletal muscle under anesthesia with isoflurane, enflurane, and halothane in an endotoxemic rat preparation. MATERIALS AND METHODS: Twenty-one Sprague-Dawley rats under continuous hemodynamic monitoring and intravital microscopy of the spinotrapezius muscle were studied during two level lipopolysaccharide (0.2 mg/kg and 2 mg/kg) induced sepsis. The effects of equianesthetic concentrations (1.5 minimum alveolar concentration [MAC]) of either isoflurane [n:7], enflurane [n:7], or halothane [n:7] on microcirculatory vasoregulation were measured and histopathologic changes were evaluated. RESULTS: During low-dose endotoxemia, arteriolar vasodilation under isoflurane was nearly abolished (P < .05). At high-dose endotoxemia, this lack of vasodilatory effect was similar (P < .05). Animals receiving 1.5 MAC of enflurane during low-dose endotoxin presented a significant decrease in arteriolar diameter by -11.3 (+/-2.9%), this response was less during high-dose endotoxemia (-7.0, +/-2.9%). Halothane caused pronounced vasoconstriction by -20 (+/-3.7%) during low-dose endotoxemia and moderate but significant constriction during high-dose endotoxemia (-7.9, +/-2.6%). CONCLUSIONS: Isoflurane, enflurane, and halothane exert significantly different effects on vasoregulation of skeletal muscle arterioles in the endotoxemic rat.

Anesthetics, Inhalation↗
PubMed2000

[Rating the perioperative period by patients. First evaluation of a new questionnaire].

OBJECTIVE: There is an increasing demand for internal clinical quality assurance. For this reason methods for the assessment of patients' satisfaction and postoperative symptoms and complaints are needed. This article describes a new questionnaire for the measurement of these aspects. METHODS: The questionnaire consists of two parts. Part 1 assesses the intensity of symptoms related to the postoperative periods "recovery room", "first hours on ward" and "current state". Part 2 measures patients' satisfaction with anesthesiological care, unspecific perioperative care and postoperative convalescence. 431 patients completed the questionnaire after an elective operation. RESULTS: Results demonstrate a plausible difference in patients' symptoms between the three postoperative periods. The difference between the remembered complaints in the "recovery room" and the "first hours on ward" is of small degree. Related to the period immediately after anesthesia, women describe a worse state of health than men. Male and female patients do not differ in their satisfaction with anesthesiological care. Older patients describe greater satisfaction with perioperative care than younger ones. There are only a few significant correlations between the intensity of symptoms in the "recovery room" and data from anesthesiological documentation. CONCLUSIONS: The new questionnaire is sensitive for the change of symptoms in the course of postoperative time. Considering the results, a modification of the questionnaire ist suggested. This instrument is to be used in a greater and representative sample of patients now.

Adult↗
PubMed2000

Changes of interstitial fluid volume in superficial tissues detected by a miniature ultrasound device.

We evaluated the changes of tissue layer thickness in circumscribed superficial tissue areas with a 10-MHz A-mode and a 20-MHz B-mode ultrasound device under alterations in body posture and plasma volume to detect fluid shifts between the different compartments. In 20 male volunteers, we measured tissue thickness by A mode and corium and subcutis thickness by B mode at the forehead before and 30 min after three procedures: change from upright to supine position (P1); change from upright to 30 degrees head-down-tilt position (P2); infusion of 10 ml/kg body wt of Ringer solution (P3). We found a significant correlation between baseline tissue thickness and the sum of corium and subcutis thicknesses (r = 0.75, P < 0.01). The changes of body posture and plasma volume resulted in significant increases of tissue thickness (P1, 2.9%; P2, 11.6%; P3, 5.8%) and corium thickness (P1, 4.7%; P2, 8.1%; P3, 9.1%) but not of the sum of chorium and subcutis thicknesses. We conclude that fluid shifts from the intravascular to the extravascular compartment are detectable by evaluating corium thickness with a B-mode, or more easily tissue thickness with an A-mode, ultrasound device.

Adult↗
PubMed2000

Measurement of fluid volume shifts during hemodialysis by A-mode ultrasonography.

BACKGROUND: The rate of intercompartmental fluid volume changes during hemodialysis (HD) is a major determinant of dialysis-induced hypotension and lacks direct monitoring. The aim of the study was to evaluate the feasibility of tissue thickness (TT) measurement in monitoring the mobilization of interstitial fluids during HD. METHODS: We studied the intradialytic changes in forehead TT and inferior vena cava diameter (IVCD) in 20 patients. Plasma refilling was calculated from changes in hematocrit (Hct) and ultrafiltration rates. RESULTS: During ultrafiltration of 2,437 +/- 117 ml (mean +/- SEM), Hct increased significantly from 27.9 +/- 0.7 to 30.0 +/- 0.9%. IVCD decreased significantly from 9.7 +/- 0.2 to 6.1 +/- 0.4 mm/m(2). We found a simultaneously pronounced reduction in TT from 4. 46 +/- 0.12 to 3.78 +/- 0.12 mm (> or =15.3%) with a significant correlation to plasma refilling (0.613). CONCLUSION: Volume changes in the peripheral shell tissues during HD can be monitored directly and noninvasively by A-mode ultrasound.

Adult↗
PubMed1999

[Diagnosis, procedures and conservative therapy of a bronchial rupture after intubation with double-lumen tube].

Bronchial rupture is a rare but severe complication of intubation with a double-lumen tube. Cardinal symptoms are mediastinal and subcutaneous emphysema as well as pneumothorax. Larger injuries result in an air leak and the endtidal carbon dioxide decreases. The gas exchange may worsen drastically when mucosal prolapse or bronchial haemorrhagia lead to bronchial occlusion. Mediastinitis or sepsis can be the sequel of the opened mediastinum. If bronchial injury is suspected probably fibreoptic bronchoscopy is indicated. We report on a case of bronchial rupture due to overinflation of the endobronchial cuff or movement of the inflated cuff when repositioning the patient. The conservative therapy was successful in spite of the fact that surgical intervention is recommended in the literature following bronchial rupture. To avoid tracheobronchial injuries an adequate tubus size must be selected. The more flexible polyvinylchloride (PVC) tubes without a carinal hook should be preferred to the Carlens tube. An atraumatic intubation is promoted by leaving the stylet inside after the tip of the tube has passed the vocal cords. To identify the minimum occlusive pressure of the endobronchial cuff for lung isolation different methods are described and should be used. The cuff has to be deflated when the patient is repositioned and when one-lung-ventilation is not required. Tumours of the tracheobronchial tree and weakness of the bronchial wall caused by steroid hormone therapy or COPD may increase the risk of tracheobronchial laceration.

Adenocarcinoma↗
PubMed1999

Measurement of peripheral tissue thickness by ultrasound during the perioperative period.

We have studied changes in peripheral tissue thickness with a novel hand-held ultrasound device during the perioperative course of 60 healthy surgical patients in three different intraoperative body positions. The nil-by-mouth period led to a significant decrease in forehead tissue thickness. Standardized infusion therapy with Ringer's solution at a rate of 8 ml kg-1 h-1 resulted in a gradual increase in tissue thickness, which was significantly different from preoperative baseline values after 90 min. Packed cell volume decreased significantly after the start of infusion and remained low over the rest of the observation time. Different body positions did not influence changes in tissue thickness. We conclude that changes in perioperative tissue thickness in healthy patients can be detected easily by ultrasound, independent of body position. This method may prove useful for the non-invasive assessment of fluid balance state.

Adult↗
PubMed1998

Perioperative tissue thickness measurement by a new miniature ultrasound device.

INTRODUCTION: A recently developed mini ultrasound device for measurement of peripheral tissue thickness is now available for use in clinical practice. Whether this device allows a better guidance of perioperative fluid therapy has to be investigated. Therefore, it is necessary to get basic data on the parameter tissue thickness in otherwise healthy patients during surgery. The aim of the present study was to evaluate differences in tissue thickness change between patients in supine and head down position with a novel handheld ultrasound device during the perioperative course of healthy surgical patients under a standardized fluid regimen. METHODS: After obtaining ethics committee approval and informed consent we studied 19 ASA 1-2 female patients undergoing gynecological procedures in supine (SUP, n = 11) or in 30 degrees head down position (HD, n = 8) in general anesthesia. Preoperative NPO status was comparable in both groups. Lactated Ringer's solution (LR) was continuously infused at a rate of 8 ml/kg b.w./h over 90 min and tissue thickness (TT) was determined by ultrasound before induction (t0) and in 30 min intervals (t30, t60, t90) at the forehead. Simultaneously plasma viscosity (PV) was evaluated. RESULTS: Group SUP presented at t0 a forehead TT of 5.3 mm (SD +/- 0.5), at t30 TT was unchanged. At t60 mean TT increased significantly to 5.6 mm, (+/- 0.6). At t90 mean TT remained stable at 5.7 mm (+/- 0.5). Group HD presented at t0 a mean TT of 4.6 mm (+/- 0.7), at t30 mean TT was 4.9 mm (+/- 0.7) and at t60 mean TT of the forehead skin was measured as 5.3 mm (+/- 0.6). Significance to t0 was reached at t90 with a mean TT of 5.4 mm (+/- 0.7). Group HD showed a steeper increase and a parallel stabilization phase at the end. Differences between t0 and t90 have been significant. Mean PV in the SUP group at t0 (1.361 mPa*s, SD: +/- 0.045) decreased under the infusion therapy to 1.276 mPa*s (+/- 0.04) at t90. Mean PV in the HD group was determined 1.351 mPa*s (+/- 0.06) at t0 and declined to 1.274 mPa*s (+/- 0.03) at t90. CONCLUSIONS: The findings suggest that fluid replacement after an NPO period and the expected changes of forehead TT due to positioning of the patient are detectable by this new ultrasound device.

Adult↗
PubMed1998

Effects of propofol vs isoflurane on respiratory gas exchange during laparoscopic cholecystectomy.

BACKGROUND: Respiratory function and pulmonary gas exchange are affected in laparoscopic procedures where a pneumoperitoneum is introduced using CO2. Previous studies have shown differing results concerning pulmonary gas exchange during laparoscopic procedures: Whereas in patients undergoing isoflurane anaesthesia decreases in PaO2 are demonstrated, this factor remains unchanged in patients undergoing propofol anaesthesia. In the present study, the effects of propofol on pulmonary gas exchange were compared with those of isoflurane in patients undergoing elective laparoscopic cholecystectomy in a prospective randomised manner. METHODS: Twenty ASA patients with physical status I and II were divided randomly between isoflurane (IG) and propofol groups (PG). After induction of anaesthesia patients were moderately hyperventilated. Respirator settings remained unchanged during pneumoperitoneum (PP) until 10 min after deflation of the peritoneal cavity. Blood gas analyses were performed at 5 time points: 15 min after induction of anaesthesia (giving pre-PP values), immediately before carbon dioxide insufflation (0 min PP), after both 30 and 60 min of PP and 10 min post PP. Inspiration plateau pressure (Pplat), compliance of the respiratory system, and both ins- and expiratory gas concentrations were continuously recorded by an Ultima V monitor (Datex Corp., Helsinki, Finland). The difference between arterial and end-tidal CO2 partial pressure (P(a-et)CO2) was calculated so as to allow assessment of physiological dead space by the modified Bohr equation. RESULTS: Pulmonary gas exchange differed significantly after 30 min of PP between the IG and the PG. At this time, PaO2 was 19.5 +/- 2.9 kPa (mean +/- SD) in the IG and 23.1 +/- 1.8 kPa in the PG (P < 0.01), whereas PaCO2 was 5.5 +/- 0.37 kPa in the IG and 4.9 +/- 0.27 kPa in the PG (P < 0.01). These discrepancies remained until after carbon dioxide desufflation. At 10 min post PP, PaO2 was 18.3 +/- 2.6 kPa in the isoflurane group and 21.9 +/- 2.2 kPa in the propofol group (P < 0.01), whereas PaCO2 was 5.4 +/- 0.46 kPa in the IG and 4.8 +/- 0.22 kPa in the PG (P < 0.01). During carbon dioxide insufflation the P(a-et)CO2 increased significantly in the IG from 0.47 +/- 0.13 kPa to 0.76 +/- 0.37 kPa (P < 0.05), while the values in the PG remained constant. CONCLUSION: This study demonstrates that pulmonary gas exchange in patients with laparoscopic cholecystectomy is affected by the choice of anaesthetic procedure. During and after laparoscopic cholecystectomy using isoflurane as the anaesthetic, the PaCO2 is significantly higher and the PaO2 significantly lower than they are with propofol.

Adult↗