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Biomedical subjects

D Kettler

Publications and source records attributed to D Kettler.

At least 109 records · Page 6Linked to original sources
PubMed1989

[A case of bronchospasm under isoflurane anesthesia].

Isoflurane is generally considered to have little effect on bronchomotor tone. The following case report shows that isoflurane anesthesia can be associated with severe bronchospasm. A 9-year-old girl (35 kg, 140 cm) with no history of asthma or drug sensitivity was scheduled for emergency appendectomy. Anesthesia was induced with fentanyl, methohexital, and vecuronium. Breath sounds were normal prior to induction and after endotracheal intubation. Isoflurane was added to the gas mixture 5 min after the last injection. Almost immediately after isoflurane was added the mean inspiratory pressure increased from 15 to ca. 35 cm H2O, expiration was prolonged, and wheezing was heard on auscultation. End-expiratory CO2 increased from 5.1% to more than 8% (pCO2 ca. 60 mmHg). Halothane was substituted for isoflurane and theophylline was injected, i.v. shortly after which the inspiratory pressure decreased, the wheezing improved, and the end-expiratory CO2 returned to normal. The remaining course and postoperative period were uneventful. Isoflurane is considered to be the causative agent in this case. Other possible mechanisms are discussed and pertinent literature is reviewed.

Anesthesia↗
PubMed1989

Sufentanil does not block sympathetic responses to surgical stimuli in patients having coronary artery revascularization surgery.

The effects of a moderate dose of sufentanil (1 microgram.kg-1 + 0.015 micrograms.kg-1.min-1) plus nitrous oxide (30% O2/70% N2O) anesthesia (group I; n = 8) and of high-dose sufentanil/O2 anesthesia (10 micrograms.kg-1 + 0.15 micrograms.kg-1.min-1) without N2O (group II; n = 8) on cardiovascular dynamics, myocardial blood flow, myocardial oxygen consumption, myocardial lactate balance, and hypoxanthine release were studied in two groups of male patients scheduled for elective coronary artery bypass surgery. All patients were on maintenance doses of calcium channel blockers and nitrates with the last doses of medications given the morning of operation. All patients were premedicated with flunitrazepam (2 mg orally), piritramide (7.5 mg IM) and promethazine (25 mg IM). Measurements were performed before the induction of anesthesia with the patients premedicated but awake; 20 min after induction of anesthesia with sufentanil plus pancuronium 0.1 mg.kg-1 for muscle relaxation before surgery; and during sternotomy and sternal spread. Sufentanil at either dose decreased mean arterial pressure, as well as cardiac and stroke volume index while heart rate remained unchanged. Following the induction myocardial blood flow and myocardial oxygen consumption decreased 23% (79 ml.min-1.100 g-1 to 61 ml.min-1.100 g-1 and 28% (9.2 ml O2.min-1.100 g-1 to 6.6 ml O2.min-1.100 g-1) in group I and 14% (78 ml.min-1.100 g-1 to 67 ml.min-1.100 g-1 and 18% (8.7 ml O2.min-1.100 g-1 to 7.1 ml O2.min-1.100 g-1) in group II. Myocardial ischemia was seen in one patient of group II (patient No. 4), as indicated by a hypoxanthine release into the coronary sinus, when after the induction MAP decreased from 93 to 67 mm Hg and heart rate increased from 56 to 71 min-1. During sternotomy 8 of 16 patients (50%) developed hypertension and 9 of 16 patients (56%) showed signs of myocardial ischemia, i.e., a lactate and hypoxanthine release.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Opiate modulation of the stress-induced increase of vasoactive intestinal peptide (VIP) in plasma.

Vasoactive intestinal peptide (VIP) has a variety of extra-intestinal actions which are typical of the body's reaction to stress, such as lipolysis, glycogenolysis and modulation of anterior pituitary hormone secretion. Serial VIP plasma concentrations in patients undergoing major laparotomies were determined. The influence of the mu-receptor agonist, fentanyl, on intra-operative changes was investigated and compared to a control group receiving halothane anesthesia. Plasma levels of typical "stress hormones" cortisol and catecholamines were also monitored for additional information on the extent of perioperative stress. VIP levels increased intraoperatively in the halothane group from 5.9 +/- 4.6 to 15.3 +/- 5.3 pmol/l. Cortisol and catecholamine levels showed a similar increase. The intraoperative VIP increase in the fentanyl group was significantly smaller: 3.5 +/- 1.9 to 7.3 +/- 3.6 pmol/l. Anesthesia itself did not affect VIP concentrations as shown by constant levels during a 30 minute preoperative control period. The observed increases of VIP plasma concentration are thought to reflect a possible role for VIP in the hormonal metabolic response to stress. The attenuation of the increase by fentanyl might be due to a direct opiate action on VIP release.

Anesthesia, Inhalation↗
PubMed1988

[Relation of the inhibition of cortisol synthesis in vivo to plasma etomidate concentrations].

Young, healthy male patients undergoing body surface surgery under fentanyl-nitrous oxide-oxygen anesthesia were given an etomidate bolus for induction (0.3 mg/kg body weight) followed by a continuous infusion (0.36 mg.kg-1.h-1). The total etomidate dose was 63 +/- 6.4 mg (mean +/- standard error). Basal cortisol levels as well as the adrenocortical response to exogenous synthetic ACTH1-24 (0.25 mg i.m.) were determined preoperatively, at the end of anesthesia, and 6 and 20 h postoperatively. The reduction of the response to ACTH stimulation measured postoperatively as compared to preoperatively was calculated as percentage of the preoperative response. Plasma concentrations of etomidate were measured at the same sample times by gas chromatography. At the end of anesthesia the plasma level was 570 +/- 131 nM (mean +/- standard error). It decreased to 99 +/- 23 nM 6 h later and to 43 +/- 3 nM 20 h postoperatively. The plasma concentrations were plotted against the inhibition data. We found a sigmoid relationship between the relative inhibition and the log of the etomidate concentrations. We determined an EC50 for inhibition of 110 nM that agrees well with published data. We also found that the cortisol response was not completely suppressed at the concentrations measured here. This supports the results of a previous study in which we found that patients undergoing cardiovascular surgery still exhibited intra- and postoperative cortisol increases although they had been given large doses of etomidate. We conclude that the suppression of corticosteroid synthesis caused by etomidate is concentration-dependent. The suppression is negligible at concentrations lower than 40 nM.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Global and regional myocardial blood flow and metabolism during equipotent halothane and isoflurane anesthesia in patients with coronary artery disease.

Global and regional myocardial blood flow and metabolism were examined in 20 patients with coronary artery disease before surgical stimulation. Half were anesthetized with halothane (0.8%) and half with isoflurane (1.2%). Coronary perfusion pressure decreased similarly in both groups. During halothane anesthesia coronary sinus blood flow, an index of global perfusion, decreased from an awake value of 129 +/- 7 to 97 +/- 7 ml/min (P less than 0.05), and great cardiac vein blood flow, an index of regional perfusion, decreased from 60 +/- 8 to 44 +/- 5 ml/min (P less than 0.05). In contrast, during isoflurane anesthesia global coronary blood flow increased from 131 +/- 13 to 153 +/- 16 ml/min (P less than 0.05), while regional blood flow decreased from 68 +/- 7 to 56 +/- 6 ml/min (P less than 0.05). Thus, the ratio of great cardiac vein blood flow to coronary sinus blood flow was unchanged during halothane anesthesia but decreased significantly during isoflurane. Neither global nor regional coronary vascular resistance was altered by halothane, whereas isoflurane decreased global coronary vascular resistance without affecting regional coronary vascular resistance. All patients receiving halothane had net myocardial lactate extraction. In the isoflurane group, four patients showed global lactate production and three regional lactate production. All patients demonstrating lactate production also developed electrocardiographic evidence of myocardial ischemia, which was not present before induction. The authors conclude that halothane is a preferable anesthetic to isoflurane in patients with coronary artery disease because the latter has the propensity to induce maldistribution of the coronary circulation and myocardial ischemia.

Adult↗
PubMed1987

[Special problems of coronary patient: viewpoint of the anesthesiologist].

1) Patients with ischaemic heart disease have a substantial increased risk to develop perioperative myocardial infarction (reinfarction). 2) The incidence of cardiac complications increases when surgery is performed on the great vessels and in the intrathoracic and upper abdominal region. 3) The choice of the anaesthetic is of minor importance. However, isoflurane may be particularly susceptible to produce a coronary steal phenomenon and therefore should be used with caution in patients with IHD. 4) Experience and skill of the anaesthetist is of greater importance to avoid ischaemia. Invasive monitoring and aggressive treatment of haemodynamic disorders may reduce the risk of ischaemia. 5) During recovery patients with IDH must be controlled carefully at a recovery ward or ICU. 6) Preoperative evaluation of the individual risk and specific treatment of haemodynamic and metabolic disorders are mandatory. Psychologic guidance of the patients throughout the preoperative period is important.

Anesthesia, General↗
PubMed1987

Endocrinological changes following etomidate, midazolam, or methohexital for minor surgery.

Etomidate is known to inhibit adrenocorticosteroid synthesis. The extent and duration of the effects of etomidate (63 +/- 6.4 mg) on spontaneous and stimulated corticosteroid levels, as well as on plasma concentrations of ACTH, beta-endorphin, and catecholamines were examined and compared to those following administration of the new benzodiazepine, midazolam, or of methohexital. Twenty-nine healthy, young, male orthopedic patients were randomized into three groups receiving either etomidate/fentanyl (n = 12), midazolam/fentanyl (n = 8), or methohexital/fentanyl (n = 9). Etomidate caused cortisol levels to decrease from 12.5 +/- 1.2 micrograms/dl preoperatively to 5.9 +/- 0.8 micrograms/dl after operation (P less than 0.001), compared to an increase from 12.0 +/- 1.9 micrograms/dl to 18.5 +/- 2.9 micrograms/dl in the group receiving methohexital. At 6 and 20 h postoperatively, all cortisol levels were normal. The cortisol decrease from 12.5 +/- 1.7 to 7.6 +/- 1.5 caused by midazolam was similar to that following etomidate, but the response to exogenous ACTH was significantly impaired in patients receiving etomidate as compared to those receiving midazolam. ACTH and beta-endorphin levels increased in patients receiving etomidate, presumably as a result of the interruption of negative feedback due to cortisol synthesis inhibition. Midazolam on the other hand prevented the increase of ACTH and beta-endorphin levels. Etomidate completely suppressed spontaneous aldosterone levels (from 33 +/- 6.7 to 7 +/- 2.1 pg/ml), as well as the response to stimulation with exogenous ACTH without affecting serum electrolytes. Etomidate had no influence on plasma catecholamines, but midazolam attenuated the stress-related epinephrine increase.

Adrenocorticotropic Hormone↗
PubMed1987

[Changes in expression of lymphocyte surface markers following administration of etomidate, midazolam or methohexital].

Stress alters cellular immunity, affecting lymphocyte function, total lymphocyte count, and the frequency distribution of the lymphocyte subpopulations. Cortisol may mediate these stress-related changes, and drugs affecting cortisol levels might therefore alter lymphocyte patterns. Etomidate and midazolam both prevent the normal perioperative cortisol increase in minor surgery, but the mechanisms by which they do this are not identical: etomidate inhibits steroid synthesis in the adrenal cortex, leading to low cortisol and high ACTH levels, whereas midazolam primarily prevents ACTH increases. Methohexital has little or no influence on cortisol levels. By comparing the effects of these three drugs on the expression of lymphocyte surface markers and the interleukin-2 (Il-2) receptor, we hoped to gain further information on the effects of perioperative cortisol changes on cellular immunity. METHODS. Healthy, young male patients scheduled for routine body surface operations were premedicated with 2 mg flunitrazepam the evening before surgery and 50 mg promethazine and 15 mg piritramide i.m. 1 h before arrival in the operating room. Anaesthesia was induced with 0.2-0.3 mg fentanyl, 2 mg pancuronium, and either etomidate (0.3 mg/kg body wt.), midazolam (0.2 mg/kg body wt.), or methohexital (1.5 mg/kg body wt.). The induction bolus was followed by an infusion at the rate of 0.36 mg/kg/h for etomidate, 0.09 mg/kg/h for midazolam, and no infusion for methohexital. Intubation was facilitated with 100 mg succinylcholine. The patients were ventilated to normocapnia with 66% nitrous oxide in oxygen. Fentanyl was given as 0.1 mg bolus injections whenever necessary.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1986

Effects of propofol on cardiovascular dynamics, myocardial blood flow and myocardial metabolism in patients with coronary artery disease.

The effects of propofol (emulsion formulation) on cardiovascular dynamics, myocardial blood flow and myocardial metabolism were studied in 12 patients scheduled for elective coronary artery bypass surgery. Measurements were performed with the patient awake, during steady-state maintenance anaesthesia with propofol 200 micrograms kg-1 min-1 at rest, and during sternotomy when the propofol was supplemented with fentanyl 10 micrograms kg-1. Propofol alone decreased mean arterial pressure and cardiac index; heart rate was increased. Myocardial blood flow and myocardial oxygen consumption were decreased by 26% and 31%, respectively. Myocardial lactate production was seen in one patient during this period. Surgical stimulation, under propofol-fentanyl anaesthesia, led to the return of arterial pressure and heart rate towards baseline; cardiac index decreased further. Myocardial blood flow and oxygen consumption increased such that they almost achieved their baseline values. Myocardial lactate production was seen in one patient. These results suggest that propofol may on occasions, lead to myocardial ischaemia in patients with coronary artery disease, but that it is able to block the sympathetic responses to surgical stimulation when combined with a suitable analgesic.

Adult↗
PubMed1985

[Complications of continuous arteriovenous hemofiltration].

Among annually 10 treatments with continuous arteriovenous haemofiltration (CAVH) during the last years there were some individual instances of severe complications: occluding thrombus in the femoral artery, infection at the site where the arterial catheter was inserted and disconnection in the extracorporeal shunt. When choosing the method for compensating renal failure, the possibility of these complications must be considered. Patients who will tolerate intermittent hyperhydration between two dialysis sessions should be treated discontinuously with a technique not-employing arterial cannulation rather than with CAVH.

Blood Physiological Phenomena↗
PubMed1984

[Rewarming from moderate to deep hypothermia: plasma catecholamine content, metabolism and circulatory function. 2 case reports].

Two patients were rewarmed from hypothermia (esophageal temperature 27.2 degrees C, 27.5 degrees C respectively). The first case suffered from head-injury after alcohol ingestion and was deeply comatose. A metabolic or cardiovascular regulatory response to cold was not observed in this patient. The relationship between esophageal temperature and whole-body-oxygen consumption was quantified with a Q10 of 2.75 during rewarming (27.2-37.2 degrees C). His epinephrine levels were greatly elevated to 1,000 pg/ml whereas norepinephrine levels were only moderately increased to 250 pg/ml. Premature ventricular contractions (PVCs) during intubation or from the pulmonary artery catheter were not observed. The second patient was a 87 year old man with accidental hypothermia. He exhibited shivering at an esophageal temperature of 27.5 degrees C which indicated persistent thermoregulation. In contrast to the first case his norepinephrine levels were elevated to 1,500 pg/ml and his epinephrine levels only to 450 pg/ml. After onset of surface rewarming an additional increase in norepinephrine levels was observed and an increasing rate of PVC's (15/min) recorded, which ceased when temperature returned to normal. Our observations indicate that part of the cardiac complications during rewarming from deep hypothermia may result from thermoregulation and additional catecholamine liberation.

Adult↗
PubMed1982

Myocardial blood flow and oxygen consumption during high-dose fentanyl anesthesia in patients with coronary artery disease.

The effects of high-dose fentanyl-oxygen anesthesia (100 micrograms/kg) on myocardial blood flow (argon washin), myocardial oxygen consumption, myocardial lactate balance, and cardiovascular dynamics were studied in nine patients undergoing three-vessel coronary artery bypass operations. All patients had been on maintenance doses of a beta-receptor blocker (pindolol). Except for pindolol all medication had been discontinued 48 hours prior to the study. Measurements were performed in the awake state, after 10 micrograms/kg fentanyl, after 100 micrograms/kg fentanyl, and during sternotomy. Moderate doses of fentanyl (10 micrograms/kg) produced minimal changes in myocardial blood flow, myocardial oxygen consumption, and cardiovascular dynamics; myocardial oxygen balance as well maintained. Large doses of fentanyl (100 micrograms/kg) produced a 16 per cent decrease in mean aortic pressure, cardiac index did not change significantly, while stroke volume index decreased by 23 per cent. Myocardial oxygen consumption decreased by 14 per cent and myocardial blood flow by 10 per cent. Myocardial lactate production was observed in five patients, indicating myocardial ischemia. During sternotomy arterial pressure and heart rate increased 8 per cent and 29 per cent, respectively, resulting in an increase in myocardial work, as reflected by a 38 per cent increase in myocardial oxygen consumption and by a 54 per cent increase in myocardial blood flow. Myocardial lactate production was observed in seven of nine patients. Our data demonstrate that in patients on maintenance doses of beta-receptor blockers, large doses of fentanyl as the sole "anesthetic" produce incomplete anesthesia and fail to protect the myocardium from ischemia due to noxious stimuli during coronary artery surgery.

Adult↗
PubMed1981

[The effect of midazolam on general hemodynamics and cerebral blood flow in animals and man (author's transl)].

8-Chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a] [1,4]benzodiazepine (midazolam Ro 21-3981, Dormicum) has a number of useful properties--including good tolerance on i.v. injection, and short duration of action--which make it a valuable substance in anesthesiology. The present study deals in particular with the general, coronary and cerebral hemodynamics. Observed hemodynamic effects lasted no more than 10 min, which renders midazolam a drug of good controllability.

Anesthetics↗