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K Peter

Publications and source records attributed to K Peter.

At least 109 records · Page 6Linked to original sources
PubMed1997

Halothane, isoflurane, and sevoflurane reduce postischemic adhesion of neutrophils in the coronary system.

BACKGROUND: Polymorphonuclear neutrophils (PMNs) contribute to postischemic reperfusion damage in many organs and tissues, a prerequisite being adhesion of PMNs to vascular endothelial cells. Because adhesion processes involve orderly interactions of membrane proteins, it appeared possible that "membrane effects" of volatile anesthetics could interfere. We investigated the effects of halothane, isoflurane, and sevoflurane on postischemic adhesion of human PMNs in the intact coronary system of isolated perfused guinea pig hearts. METHODS: The hearts (n = 7-10 per group) were perfused in the "Langendorff" mode under conditions of constant flow (5 ml/min) using modified Krebs-Henseleit buffer equilibrated with 94.4% oxygen and 5.6% carbon dioxide. Global myocardial ischemia was induced by interrupting perfusion for 15 min. In the second minute of reperfusion (5 ml/min), a bolus dose of 6 x 10(5) PMNs was injected into the coronary system. The number of cells reemerging in the coronary effluent was expressed as a percentage of the total number of applied PMNs. Halothane, isoflurane, and sevoflurane, each at 1 and 2 minimal alveolar concentration (MAC), were vaporized in the gas mixture and applied from 14 min before ischemia until the end of the experiment. RESULTS: Under nonischemic conditions, 24.7 +/- 1.3% of the injected neutrophils did not reemerge from the perfused coronary system. Subjecting the hearts to global ischemia augmented retention (36.4 +/- 2.8%, P < .05). Application of halothane reduced adhesion of neutrophils to 22.6 +/- 2.1% and 24.2 +/- 1.8% at 1 and 2 MAC, respectively (P < .05). Exposure to 1 and 2 MAC isoflurane was similarly effective, whereas basal adhesion was not significantly influenced. Sevoflurane-treated hearts (1 and 2 MAC) also showed decreased adhesion of PMNs (23 +/- 2.3% and 24.8 +/- 1.8%, respectively; P < .05) and an identical reduction resulted when sevoflurane (1 MAC) was applied only with the onset of reperfusion. CONCLUSIONS: Although the mechanism of action of volatile anesthetics remains unclear in these preliminary studies, their inhibitory effect on ischemia-induced adhesion of PMNs may be beneficial for the heart during general anesthesia.

Anesthetics, Inhalation↗
PubMed1997

Hyperosmotic-hyperoncotic solutions during abdominal aortic aneurysm (AAA) resection.

A largely positive perioperative fluid balance during both elective and emergency abdominal aortic aneurysm repair (AAA) may put patients at risk of developing left ventricular failure and may thus contribute to morbidity. In the present paper we report on a prospective study using hyperosmotic-hyperonocotic solutions (HHS) infused during clamping of the aorta, for the prevention of declamping shock, and the associated reduction in perioperative fluid requirements. The major aim of this paper was to determine the efficacy of an HHS infusion when given over 20 minutes and to detect possible adverse effects of HHS. For perioperative fluid replacement 12 patients received crystalloid solutions with HHS [250 ml of 7.2% NaCl combined with either 6% Dextran (n = 3), 6% Hydroxyethylstarch (HES, n = 4) or 10% HES (n = 5)]. In 16 controls, crystalloids with 1000 ml of HES 10% were infused. Patients were invasively monitored and hemodynamic parameters frequently assessed during the operation, which were statistically analyzed in relation to the start of the fluid loading during clamping of the aorta. One patient showed an anaphylactoid reaction to HES, otherwise no side effects of HHS were observed during infusion (no hypotension, no pathological EKG changes). Plasma sodium and chloride concentration as well as osmolality rose resulting in an osmotic gradient and a desired intravascular volume expansion. Prior to declamping pulmonary capillary wedge pressure had increased to the desired value of > 13 mmHg and < 18 mmHg. Oxygen delivery was significantly elevated upon HHS and remained so post declamping, whereas no change was observed in controls. During clamping systemic vascular resistance was significantly decreased, but was unchanged in controls. The perioperative fluid balance of patients receiving HHS was 2471.0 +/- 948.6 ml, which was significantly less than + 3386.7 +/- 1247.9 ml of controls (P < 0.01). We suggest that HHS opens new perspectives in perioperative fluid management of both elective and emergency AAA repair, since hemodynamic parameters are improved and the overall fluid balance is less positive, thus decreasing the likelihood of edema formation. Moreover, the previously described positive microcirculatory effects of HHS may be particular beneficial in some high-risk patients.

Aged↗
PubMed1997

Effects of adenosine on the functions of circulating polymorphonuclear leukocytes during hyperdynamic endotoxemia.

Endotoxin-activated polymorphonuclear leukocytes (PMNL) adhere to the vascular endothelium and cause damage by the release of toxic superoxide anions (O2-). Because adenosine is a potent inhibitor of PMNL in vitro, the present study investigates the effects of this nucleoside on the functions of circulating PMNL in a standardized porcine model of hyperdynamic endotoxemia. Ten anesthesized pigs received an intravenous (i.v.) 330-min infusion of endotoxin (5 microg/kg of body weight per h). Another 10 pigs were also infused with endotoxin plus adenosine (150 microg/kg/min [i.v.]); this treatment was begun 30 min prior to the beginning of endotoxin treatment. Control groups (five animals per group) received either adenosine or physiological saline. Infusion of endotoxin caused severe neutropenia, shedding of L-selectin, upregulation of beta2-integrins, increased binding of C3-coated zymosan particles, and subsequent phagocytosis by PMNL. While phagocytosis-induced production of oxygen radicals appeared to decrease, extracellular release of superoxide anions was strongly enhanced. Infusion of adenosine during endotoxemia had no effect on neutropenia, expression of adhesion molecules, C3-induced adhesion, phagocytosis, or intracellular production of oxygen radicals, whereas extracellular release of O2- was strongly inhibited. Thus, i.v. infusion of adenosine during endotoxemia could be useful in protecting from O2(-)-mediated tissue injury without compromising the bactericidal mechanisms of PMNL.

2-Chloroadenosine↗
PubMed1997

Expression of beta 2-integrins and L-selectin on polymorphonuclear leukocytes in septic patients.

Adhesion molecules on polymorphonuclear leukocytes (PMNL) play an important role in nonspecific defense mechanisms directed at invading microorganisms. When local infection, however, cannot be controlled, a systemic inflammatory response syndrome (SIRS) ensues which may progress to septic shock and multiple organ failure, these being major determinants of the patient's outcome. In the present study, the expression of beta 2-integrins and L-selectin on blood PMNL was measured on subsequent days in patients with sepsis (n = 17) and in healthy volunteers (n = 15). beta 2-Integrins and L-selectin molecules were detected by flow cytometry, using the monoclonal antibodies IB4 (anti-CD18) and Dreg200 (anti-CD62L), respectively. Adhesion molecules were determined at baseline immediately after blood collection and also 45 min after incubation of cells in vitro at body temperature to allow for spontaneous regulation. In addition, PMNL were activated by receptor-dependent and receptor-independent stimuli to characterize stimulus-specific adhesion molecule expression. In parallel with the measurement of adhesion molecules, severity of sepsis was assessed by the Elebute score. The results demonstrate significant differences in the basal, spontaneous and stimulus-induced expression of adhesion molecules between healthy volunteers, survivors (n = 11) and nonsurvivors (n = 6). Moreover, when survivors and nonsurvivors with severe sepsis (Elebute score > 12) were compared, basal expressions of both beta 2-integrins and L-selectin were significantly lower in patients who did not survive. Thus, measurement of adhesion molecules on circulating PMNL may be useful to identify septic patients at high risk for lethal outcome.

Adult↗
PubMed1997

Circulating vascular cell adhesion molecule-1 correlates with the extent of human atherosclerosis in contrast to circulating intercellular adhesion molecule-1, E-selectin, P-selectin, and thrombomodulin.

Secondary prevention of atherosclerosis, especially before the onset of symptoms, appears desirable and could be possible with a serum marker detecting atherosclerosis. Circulating, shedded forms of adhesion molecules may serve as such because their expression is upregulated in atherosclerotic plaques. In 52 patients with peripheral arterial vascular disease (Fontaine class IIa, 7 patients; class IIb, 29 patients; and class III, 16 patients), the extent of atherosclerosis was evaluated on the basis of angiograms of a large portion of the arterial system. The area diseased by atherosclerosis was determined by the percentage of vessel wall irregularities of the following calculated segments: aorta (distal from the kidney arteries), common iliac artery, external iliac artery, common femoral artery, lateral circumflex femoral artery, and popliteal artery. The maximal surface area that could exhibit atherosclerotic changes was 250 cm2. The serum concentration of circulating vascular cell adhesion molecule-1 (VCAM-1) correlated with the extent of atherosclerosis (r = .8, P < .001). In contrast, circulating intercellular adhesion molecule-1, E-selectin, P-selectin, and thrombomodulin (as markers for endothelial cell damage) did not correlate with the extent of atherosclerosis. Furthermore, circulating VCAM-1 could be used to indicate stages of atherosclerosis with a high degree of statistical significance. The potential bias of factors such as age, diabetes mellitus, hypercholesterolemia, arterial hypertension, renal failure, and history of myocardial infarction on the correlation of circulating VCAM-1 with the extent of atherosclerosis could be excluded by multivariate analysis. These findings suggest an important role of VCAM-1 in atherosclerosis and may serve as the basis for further evaluation of circulating VCAM-1 as a potential serum marker for atherosclerosis.

Adult↗
PubMed1997

[The anesthetist in perioperative care].

Due to the recent development in operative medicine medical and organizational demands on perioperative patient care have changed significantly. Corresponding to the responsibility of the operative colleagues for therapy of the primary disease, anesthesiologists have to account for monitoring and treatment of vital functions throughout the perioperative period, starting from preoperative evaluation until postoperative care. The postanesthesia recovery unit has a key role in perioperative management. Beyond post-operative monitoring and stabilization of vital parameters it is increasingly used as a buffer and switch operating station, where patients are prepared and allocated to a normal ward, an observation or intensive care unit for subsequent postoperative care. The recovery unit has developed to a "multitasking" care center, which should be operational 24 h a day with an anesthesiologist present during working hours. The terminology should be changed in the future in order to better characterize the new task spectrum, e.g. in perioperative anaesthetic care unit (PACU) for medical and medicolegal reasons patient security must have absolute priority above economic aspects. Effective postoperative pain control using epidural or patient-controlled intravenous analgesia may increase patient comfort and reduce postoperative complications caused by sympathoadrenergic activation. Both method can be safely used on normal wards provided that close cooperation and training of ward personnel is guaranteed as well as continuous supervision by a specialized acute pain service.

Anesthesia↗
PubMed1997

[The Munich intensive care transport system. Patient transport and intensive care conditions].

In November 1990 a new program for transporting critically ill patients by a 24-h specialized intensive care transportation system at the Munich Hospital Grosshadern was established. All medical equipment similar to that in the ICU allows invasive and non-invasive monitoring, drug administration, and a sophisticated respiratory therapy, provided by a Siemens Servo 300 ventilator. Even extracorporal lung augmentation (ECLA) and cardiac pump assistance by special mobile devices are possible during the transport.

Aircraft↗
PubMed1996

Patency trials with reteplase (r-PA): what do they tell us?

Thrombolytic therapy has been shown to reduce mortality and morbidity after acute myocardial infarction. Therapeutic benefit seems to be directly correlated with completeness of reperfusion (Thrombolysis in Myocardial Infarction [TIMI] grade 3 flow) of the infarct-related coronary artery, as well as the timeliness of reperfusion. To determine which regimen of reteplase (r-PA), a deletion mutant of wild-type tissue plasminogen activator (t-PA), is most effective for clinical thrombolysis, several reteplase regimens were compared with the most successful standard regimens of recombinant t-PA (alteplase) in 2 large-scale, randomized studies. All patients received aspirin and intravenous heparin. In the Reteplase Angiographic Phase II International Dose Finding Trial (RAPID-1), results in 606 randomized patients showed that a 10 + 10 U double bolus of reteplase was more effective than a 15 U single bolus, a 10 + 5 double bolus, or conventional alteplase (100 mg over 3 hours). In the Reteplase versus Alteplase Patency Investigation During Acute Myocardial Infarction (RAPID-2) trial, results in 324 patients showed that significantly more patients achieved patency of the infarct-related artery (TIMI grade 2 or 3 flow) at 90 minutes with reteplase (10 + 10 U double bolus) than with accelerated alteplase (100 mg over 90 minutes): 83.4% versus 73.3%, respectively (p = 0.03). The incidence of complete patency (TIMI grade 3 flow) at 90 minutes was likewise greater with reteplase than with accelerated alteplase (59.9% vs 45.2%, respectively; p = 0.01). At 60 minutes, the incidence of TIMI grade 2 or 3 flow was also significantly higher with reteplase than with alteplase (81.8% vs 66.1%, respectively; p = 0.01), as was the incidence of TIMI grade 3 flow (51.2% vs 37.4%, respectively; p < 0.031). The 35-day mortality rate was 4.1% for reteplase and 8.4% for alteplase (p = not significant). Reteplase and alteplase did not differ significantly with regard to the occurrence of severe bleeding (12.4% vs 9.7%, respectively) or hemorrhagic stroke (1.2% vs 1.9%, respectively). The results of these trials show that reteplase, given as a 10 + 10 U double bolus, achieves significantly higher rates of early reperfusion of the infarct-related coronary artery and is associated with significantly fewer acute coronary interventions when compared with front-loaded alteplase. The benefits of reteplase are achieved without any apparent increased risk of complications.

Cerebral Hemorrhage↗
PubMed1996

Time discrete, near infrared photoplethysmography (NIRP) for non-invasive investigation of the volume pulse in man.

UNLABELLED: In pulse oximetry the principles of photoplethysmography are used for determination of heart rate and in some devices to also display the volume pulse. It has been suggested, that a more detailed analysis of the signal may allow quantitative analysis of peripheral hemodynamic events. We describe a new computer assisted time discrete analysis of the volume pulse, studying its reliability and the method s fundamental assumption of a linear relationship between changes in amplitude and changes in time sequences of the volume pulse. METHOD: In a finger clip two diodes emit near infrared (840 nm, NIR) and red light (640nm, RED) into the finger tip, where it is remitted mainly by the erythrocytes. 70 sec of recorded signal is filtered and the resulting volume pulse analysed off-line using a computer. On each volume pulse the time of the first (Tmax), the second maximum (time of dicrote, Td) and the duration of the volume pulse (Tp) are measured and the mean values displayed. In addition, the fundamental arterial oscillation Tag = Td - Tmax and all the above values in relation to Tp are calculated. Using NIRP, 54 healthy young volunteers (19 female, mean age 27.0 +/- 3.4 years) were studied and the individual mean values calculated from 960 measurements. The reliability during 10 repetitive measurements was investigated in 26 of the 54 volunteers. In 12 subjects 5 repetitive measurements were obtained from each finger and compared with each other. In 11 subjects the linear relationship between amplitude and time sequence was tested on > 30 000 single volume pulses. The finger clip photoelectrode was levelled with the right atrium in all measurements, skin close to the clip and room temperature were recorded. RESULTS: From the mean individual values the following time discrete values were calculated for the NIR signal (n = 41): Tp = 882.3 +/- 142.6 ms, Tmax = 214.8 +/- 28.3 ms, Td = 452.7 +/- 32.4 ms, Tdec = 667.4 +/- 133.6 ms, Tag = 237.9 +/- 36.3 ms, Tmax/Tdec = 0.34 +/- 0. 07, Td/Tdec = 0.7 +/- 0.11. For each parameter the individual standard deviation during 10 repetitive measurements (26 subjects) ranged between 2.2 and 6.1%. The time sequences found were not significantly different between the individual fingers. A linear relationship between changes in time sequence and changes in amplitude was found in all tested subjects (mean r = 0.96). CONCLUSION: These results show, that the values obtained with time discrete NIRP are highly reproducible and show an individual SD of less than 6.5% under steady state conditions. The linear relationship between time sequence and amplitude found in the present study has to be confirmed in further studies on patients with pathologies of the macro- and microcirculation.

Adult↗
PubMed1996

Effect of adenosine on the expression of beta(2) integrins and L-selectin of human polymorphonuclear leukocytes in vitro.

Adenosine has been shown to inhibit the adhesion of polymorphonuclear leukocytes (PMNL) to the vascular endothelium. Because the underlying molecular mechanisms have not been fully understood, the present study characterizes the effect of adenosine on the expression of adhesion molecules of human PMNL. When PMNL were activated by N-formyl-methionyl-leucyl-phenylalanine the number of cell surface beta2 integrins increased fivefold, whereas L-selectin molecules were completely shed. Activation-dependent numerical up-regulation Of beta2 integrins and shedding of L-selectin were inhibited by exogenously applied adenosine receptor agonists in a concentration-dependent fashion. The rank order of potencies of adenosine receptor agonists, measured by the agonists' half-maximal inhibitory concentrations, revealed that adenosine inhibited the numerical up-regulation of beta2 integrins and shedding of L-selectin most likely via an A2(a) receptor site. When extracellular concentrations of endogenously formed adenosine were enhanced by the nucleoside uptake inhibitor dipyridamole, up-regulation of beta2 integrins, and shedding of L-selectin was again inhibited. Both effects were reversed by the enzyme adenosine deaminase, which degrades active adenosine to inactive inosine, suggesting that endogenously formed adenosine may play an important role in the regulation of beta2 integrins and L-selectin of human PMNL.

2-Chloroadenosine↗
PubMed1996

A comparison of the adrenocortical response during septic shock and after complete recovery.

OBJECTIVE: To compare the adrenocortical response to corticotropin during septic shock and after complete recovery. DESIGN: Prospective clinical study. SETTING: Multidisciplinary intensive care unit in a university hospital. PATIENTS: 20 consecutive patients surviving septic shock. All patients met the American College of Chest Physicians/Society of Critical Care Medicine criteria for septic shock. In addition, the presence of high-output circulatory failure with a cardiac index > 41/min per m2 was a criterion for enrollment in the study. Complete recovery from septic shock was defined as discontinuation of any supportive therapies. Severity of illness during septic shock and after recovery was graded using the Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system. INTERVENTIONS: In each patient, two short corticotropin stimulation tests were done during septic shock and after recovery. MEASUREMENTS AND RESULTS: Basal cortisol levels recorded during septic shock and after recovery did not differ (medians: 18.8 vs 18.9 micrograms/dl). However, the response to corticotropin was significantly attenuated during septic shock when compared with the response after recovery (medians: 7.7 vs 14.7 micrograms/dl; p = 0.02). After recovery, patients' stress response was less, as indicated by a reduction in APACHE II scores (medians: 21 vs 5 points; p < 0.01). CONCLUSIONS: Adrenocortical response to corticotropin is attenuated in patients with septic shock and high-output circulatory failure compared to the response in the much less stressful condition after recovery. The attenuated adrenocortical responsiveness may be explained by effects of circulating mediators from the systemic inflammatory response.

APACHE↗
PubMed1996

[The role of polymorphonuclear neutrophilic leukocytes in the pathogenesis of acute respiratory distress syndrome (ARDS)].

Polymorphonuclear leukocytes (PM-NL) constitute the first line of defence in the protection of the host from invading microorganisms. PMNL also contribute to the removal of cellular debris from necrotic tissues during reparative processes. For these purposes PMNL are armed with highly efficient bactericidal mechanisms which, under certain pathophysiological conditions, can be turned against the host himself. A vast body of evidence indicates that PMNL are able to cause lung injury which may be followed by the development of acute respiratory distress syndrome (ARDS). Accordingly, in patients with ARDS blood concentrations of inflammatory activators of PMNL are elevated, cytotoxic mechanisms of PMNL are enhanced and sequestration of these cells has been demonstrated to be inversely proportional to gas exchange. The manifestation of ARDS in leukopenic patients, however, indicates the development of this clinical syndrome independently of the presence of PMNL. The ability to differentiate between PMNL-dependent and PMNL-independent pathways in the pathogenesis of this syndrome is not only of theoretical interest but also of therapeutic significance. Since the patient's systemic inflammatory response may vary according to the stage and type of the underlying disease, an exact qualitative and quantitative analysis of PMNL functions may provide the rationale for new anti-inflammatory drug regimens aimed at modifying the host's response without increasing the risk of infection.

Acute Disease↗
PubMed1996

[Awakening from anesthesia and recovery of cognitive function after desflurane or isoflurane].

UNLABELLED: Desflurane is a new volatile anaesthetic with an extremely low blood/gas partition coefficient of 0.42. This should provide a rapid recovery from anaesthesia. METHODS: We studied 100 adult patients, ASA class I or II, undergoing elective orthopaedic surgery randomly assigned to anaesthesia with desflurane (n = 50) or isoflurane (n = 50) supplemented by nitrous oxide in oxygen. Clorazepat was given for premedication, fentanyl and thiopental for induction of anaesthesia, followed by maintenance with desflurane or isoflurane as clinically appropriate. Emergence from anaesthesia was measured as well as return of cognitive functions (extended Aldrete score, digit symbol substitution test, and visual analogue scales [VAS]). RESULTS: While the demographic characteristics and administrated doses of fentanyl and thiopental were comparable, the recovery profiles in both groups were different. After discontinuation of the volatile anaesthetics, times to extubation and ability to follow simple commands were significantly shorter after desflurane than after isoflurane. Extended Aldrete scores, estimation of the patients' physical condition, results of the digit symbol substitution test, measuring cognitive functions, and rates of drowsiness and weakness on VAS showed better recovery with less impairment of cognitive function in the desflurane group than in isoflurane patients even 120 min after anaesthesia. VAS pain scores and doses of analgesic drugs given within the first 2 postoperative hours, however, showed no significant differences. Desflurane patients were also judged fit for discharge from the recovery room significantly faster. CONCLUSIONS: Our results demonstrate that desflurane anaesthesia, even when supplemented by premedication, intraoperative opioids, and nitrous oxide may offer clinical advantages over isoflurane as far as the post-anaesthetic recovery profile is concerned.

Adult↗
PubMed1996

[Serum protein binding of fentanyl. The effect of postoperative acute phase reaction with elevated alpha 1-acid glycoprotein and methodologic problems in determination by equilibrium dialysis].

Numerous basic drugs are extensively bound to alpha 1-acid glycoprotein. Fentanyl, with a pKa value of 8.43, is also a basic drug. Protein binding studies have yielded contradictory results concerning binding of fentanyl to alpha 1-acid glycoprotein. In this study we investigated time courses of serum protein concentrations and serum protein binding of fentanyl during postoperative acute phase reaction, assuming that an increase of alpha 1-acid glycoprotein is accompanied by an increase of serum protein binding, if fentanyl is extensively bound to alpha 1-acid glycoprotein. Fentanyl protein binding measurements using equilibrium dialysis can be affected by volume shifts and pH changes. Therefore, volume shifts from buffer to serum and the influence of various phosphate buffers on increasing pH due to loss of CO2 were also evaluated. METHODS. Thirteen patients with no history of renal or hepatic disease undergoing an operation with a significant acute phase reaction were studied. Preoperatively and on the first 3 postoperative days serum concentrations of alpha 1-acid glycoprotein, albumin, total protein and apolipoprotein A and B were determined by rocket immunoeolectrophoresis, biuret method and laser nephelometry, respectively. Corresponding serum protein binding of fentanyl was measured by adding 40 ng of fentanyl to 1 ml serum followed by equilibrium dialysis at 37 degrees C for 4 h. A 0.167 M phosphate buffer (pH 7.27), which gave a final pH of 7.40, was used. Volume shifts from buffer to serum were measured. Fentanyl concentration in serum before dialysis (FS) was determined by gas chromatography, and fentanyl concentration in buffer after dialysis (FB) was determined by radioimmunoassay. Serum protein binding (SPB) was calculated by the formula: SPB = (FS - FB - FB*c)/(FS - FB) where c is a correction factor. Ten randomly selected patient sera were dialyzed against four phosphate buffers of different pH values and molarities, and the serum pH at the end of equilibrium dialysis was measured. RESULTS. Postoperatively, the serum concentration of alpha 1-acid glycoprotein rose to 151% of the control value. In contrast, serum protein binding of fentanyl did not change significantly, with a slight decrease to 96% of control value. There was a significant decrease in serum concentrations of albumin (3rd postoperative day), total protein (2nd postoperative day) and apolipoprotein B (1st-3rd postoperative day) to 85%, 90% and 75% of control values, respectively. Changes in apolipoprotein A concentration were not significant. Protein binding of fentanyl did not correlate with alpha 1-acid glycoprotein and apolipoprotein A, but there was a positive linear relationship between protein binding of fentanyl and albumin, total protein and apolipoprotein B. At the end of equilibrium dialysis the mean volumes of the serum and buffer compartments were 1114 +/- 72 and 834 +/- 68 microliters, respectively. The two phosphate buffers, with pH 7.30 (0.15 M) and pH 7.27 (0.167 M), gave final serum pH of 7.42 and 7.40, respectively. CONCLUSIONS. Present findings suggest that in contrast to other basic drugs, fentanyl binding to alpha 1-acid glycoprotein is of minor importance. In agreement with the findings of former studies, protein binding of fentanyl depended on albumin, total protein and apolipoprotein B concentrations. Due to unspecific binding of fentanyl by hydrophobic interactions, a major role of albumin, which amounts to about 60% of total protein, seems to be evident. Determining fentanyl protein binding by equilibrium dialysis, volume shifts must be taken into account if calculation is based on fentanyl concentrations in plasma (serum) and buffer after dialysis, and an appropriate buffer must be used.

Acute-Phase Reaction↗
PubMed1996

[A comparative study of intravenous opioid analgesia. Sufentanil and alfentanil for extracorporeal shock-wave lithotripsy in urologic patients].

UNLABELLED: Extracorporeal shock-wave lithotripsy (ESWL) is the method of choice for the treatment of solitary stones in the kidney or ureter. Early lithotripters required prolonged immobility of the patient and caused considerable pain, necessitating general or epidural anaesthesia during the procedure. Modern lithotripters are quicker, but still require analgesia. Intravenous opioids are currently the drugs in favour. The opioids most commonly used are fentanyl and its shorter-acting analogue, alfentanil. The latter has a more rapid onset and, because of its reduced lipid solubility, is less cumulative. Sufentanil is a new opioid that is also of the phenylpiperidone group and has been recently licensed and introduced in Germany. Its pharmacokinetic and pharmacodynamic properties suggest an intermediate duration of action, high analgesic potency, and cardiovascular stability with diminished respiratory depression. In this prospective double-blind study, the effects of alfentanil and sufentanil on cardiovascular and respiratory parameters, the quality of analgesia, degree of sedation and the number and type of side-effects were compared. PATIENTS AND METHODS: After giving informed consent and with the approval of the hospital ethics committee, 62 patients (ASA I or II) were investigated. They were randomly allocated to two groups, either receiving sufentanil (n = 32) or alfentanil (n = 30) during ESWL. No premedication was given. Excluded were patients with pain prior to treatment, patients treated with a spasmolytic or analgesic drug and those who had undergone ESWL within the last 6 months. The loading dose was given as a 5-min infusion to each group. The heart rate, systolic and diastolic blood pressure, percutaneous oxygen saturation (SpO2), and the transcutaneous capillary carbon dioxide tension (PicCO2) were recorded prior to the procedure (i.e. before administration of opioid), after 1000 and after 2000 shock waves and then 1 and 2 h after the end of lithotripsy. After 1000 and 2000 shock waves, and 1 an 2 h after the treatment, the patients were asked to express their degree of tiredness and pain on a visual analogue scale (VAS). The occurrence of side-effects such as nausea, vomiting, pruritus or other unpleasant sensations were noted by an anaesthesia nurse. Simultaneously, the anaesthetist recorded his/her impression of the patient's tiredness and degree of pain, both by using the VAS. He was not allowed to question the patient, nor was he aware of the patient's own scores. At the end of the observation period both the patient and the anaesthetist related their overall satisfaction with the anaesthetic procedure, again by using the VAS. Data were analysed with the Mann-Whitney-U for comparisons between groups and with the Wilcoxon test within each group. The side-effects were analysed with the Chi-square test. RESULTS: The systolic and diastolic blood pressure remained stable in both groups during and after treatment. The mean heart rate was different between the two groups at the beginning, and after the end of the treatment it dropped in both groups, but no significant difference was seen between groups. The PicCO2 rose from an initial mean of 36.8 mm Hg to a maximum of 44.6 mm Hg after 1000 shock waves in the sufentanil group, and from 37.8 mm Hg to 46.0 mm Hg after 2000 shock waves in the alfentanil group. The differences were significant within groups until 1 h after the end of the treatment, but there was no significant difference between groups. The oxygen saturation SpO2 dropped slightly in both groups. The differences were not significant between groups. In the alfentanil group, one patient had a maximum carbon dioxide tension of 83 mm Hg after 2000 shock waves, whereas in the sufentanil treated group the oxygen saturation fell to 72% in one case. (ABSTRACT TRUNCATED)

Alfentanil↗