Biomedical subjects

V Lischke

Publications and source records attributed to V Lischke.

At least 37 records · Page 2Linked to original sources

PubMed2000

Percutaneous tracheostomy: ciaglia blue rhino versus the basic ciaglia technique of percutaneous dilational tracheostomy.

UNLABELLED: Percutaneous dilational tracheostomy (PDT), according to Ciaglia's technique described in 1985, has become the most popular technique for percutaneous tracheostomy and is demonstrably as safe as surgical tracheostomy. In 1999, an extensively modified technique of PDT was introduced, the Ciaglia Blue Rhino (CBR; Cook Critical Care, Bloomington, IL), that consists of one-step dilation by means of a curved dilator with hydrophilic coating. To compare CBR with the basic technique of PDT, we performed a prospective, randomized trial in 50 critically ill adults. Twenty-five of these patients had PDT, and 25 had CBR. Average operating times were <3 min for CBR (range: 50-360 s) and <7 min for PDT (range: 4-20 min; P<0.0001). Tracheostomy was successfully completed in all patients. When CBR was performed, 11 minor, nonlife-threatening complications were noted: nine fractures of tracheal cartilage and two short periods of intraoperative oxygen desaturation. During PDT, seven complications occurred, of which three were potentially life-threatening: two injuries to the posterior tracheal wall, one pneumothorax, two tracheal cartilage fractures (P< 0.05 vs CBR), one case of bleeding, and one short episode of intraoperative oxygen desaturation. Regardless of whether PDT or CBR was performed, oxygenation was not significantly affected, and there was no infection of the tracheostoma. Based on our data, we conclude that new CBR is more practicable than PDT. No life-threatening complications occurred during CBR. IMPLICATIONS: To assess practicability and safety of the Ciaglia Blue Rhino (Cook Critical Care, Bloomington, IL)-an extensively modified technique of percutaneous dilatational tracheostomy-50 critically ill adults on long-term ventilation underwent either new Ciaglia Blue Rhino or percutaneous dilatational tracheostomy in a prospective, randomized clinical trial.

Adult↗

PubMed2000

Pharmacodynamics and tolerability of acetyl starch as a new plasma volume expander in patients undergoing elective surgery.

OBJECTIVE: Acetyl starch (ACS) is a new synthetic colloid solution for plasma volume expansion and is now undergoing phase II clinical trials. We compared the pharmacodynamics and tolerability of ACS with those ofhydroxyethyl starch (HES) in 32 patients (American Society of Anesthesiologists physical status I and II) undergoing elective surgery. SUBJECTS, MATERIAL AND METHODS: In this prospective, randomized, double-blind trial patients received either 15 ml/kg ACS 6% (average molecular weight (Mw) 200,000/molar substitution (MS) 0.5) or HES 6% (Mw 200,000/MS 0.5) i.v. up to a maximum dose of 1000 ml. Hemodynamic parameters, rheologic parameters, volume effect, acid-base status as well as effects on hemostasis were studied. RESULTS: After infusion of ACS and HES there was a similar increase in central venous pressure and mean arterial pressure in both groups. Acid-base status was not significantly altered after the end of the colloid infusions. After ACS infusion, plasma acetate concentration increased from 0.13+/-0.16 mg/dl to 2.87+/-1.13 mg/dl, however, after 24 h there was no significant difference in plasma acetate concentration compared to HES. The volume effect ranged from 104-116%(ACS) and from 88-118% (HES) of the colloid dose administered. These differences were not statistically significant. Partial thromboplastin time (aPTT) was only slightly increased after ACS infusion (from 38.6+/-5.7 sec to 41.4+/-5.1 sec), but was significantly increased after HES infusion (from 38.7+/-5.7 sec to 46.1+/-7.0 sec). CONCLUSION: ACS and HES are equally effective plasma volume expanders; ACS might be a new, alternative colloid solution with fewer coagulation side-effects than HES.

Adolescent↗

PubMed1999

[Occupational exposure in the hospital to laughing gas and the new inhalation anesthetics desflurane and sevoflurane].

BACKGROUND AND OBJECTIVE: There have been few studies of the occupational exposure of the new volatile anaesthetic agents desflurane and sevoflurane. Because a health risk through long-term exposure to these inhalants cannot as yet be definitely excluded, we undertook to measure the concentrations of these three anaesthetics in different parts of the Frankfurt University Medical Centre. Considering the results the relevance of exposure for surgical and anaesthesia personnel, possible consequences due to laws and possibilities of improvement were shown. METHODS: The concentration of the three anaesthetics was measured during and after 345 procedures under general anaesthesia, using photoacoustic infra-red-spectrometry every 90 sec in the breathing zone of the same operating room personnel or in the recovery room and the intensive care unit. RESULTS: Exposure of personnel in the air-conditioned operating rooms was very low, but in those rooms that were not or inadequately air conditioned was a times very high. The level of the concentrations was also significantly related to the anaesthesia system and the distance of the exposed person to the patient. The concentration of nitrous oxide was below the maximal working-place concentration (MWC) of 100 ppm, but it exceeded the threshold concentration of 0.1 MAC, as laid down in the "Maternal Protection Law" in the surgical intensive care unit and the recovery room. There are no limiting concentrations for desflurane and sevoflurane yet but their concentrations were clearly below the MWC laid down for isoflurane and enflurane. CONCLUSION: In principle the use of inhalation anaesthetics can be considered to be without occupational health risk under the present legally defined standards of air-conditioning and the requirements of a modern occupational protection law. Because of the increased concentrations in the recovery room and intensive care unit pregnant and breast-feeding women should not work in these areas.

Air Conditioning↗

PubMed1999

[Tracheostomy in intensive care].

Tracheostomy is one of the oldest surgical procedures and in the past decades has become the method of choice in the management of patients requiring long-term mechanical ventilation. At present, several alternatives exist to conventional surgical tracheostomy, such as the percutaneous dilatational techniques according to Ciaglia (PDT), Griggs (GWDF), and Schachner (Rapitrach). In particular, PDT according to Ciaglia which was introduced in 1985, has been recognized as an equally safe, but less expensive procedure than conventional tracheostomy. Fantoni's translaryngeal percutaneous technique is another new and safe procedure, which was first performed in 1996. Nonetheless, we believe that percutaneous procedures should only be performed by experienced physicians who are well-trained in both endotracheal intubation and mask ventilation. Furthermore, the capacity to perform surgical tracheostomy immediately in case of complications should be given. Only if the contraindications are carefully observed, will these new procedures retain their value and benefit in airway management of long-term ventilated patients.

Critical Care↗

PubMed1999

[Percutaneous tracheotomy in intensive care. Practicability and early complications of the translaryngeal Fantoni technique].

Tracheostomy is considered the airway management of choice in long-term ventilated ICU patients. In the last few years, percutaneous dilatational tracheostomy (PDT) has been established as an attractive and safe alternative to conventional open tracheostomy. Recently, there is another percutaneous technique according to Fantoni with translaryngeal airway access (TLT) available. Our study seeks to evaluate TLT in terms of complications and practicability. In 47 patients of our surgical ICU, elective TLT was performed. Mean operative time was 9.8 +/- 10.9 (range 6-27) minutes. Severe complications, such as bleeding, aspiration or infection of the tracheostoma have never been noted. A slight deterioration of arterial oxygen tension occurred in 25 patients intraoperatively, demanding to rise the concentration of inspired oxygen temporarily. However, no patient became hypoxic during the procedure. Since during the procedure gas exchange may worsen, TLT should not be employed in patients whose inspired oxygen concentration exceeds 80%. Despite the fact that severe complications associated with TLT have recently not yet been reported, physicians who perform TLT should be well-trained in the technique of conventional open tracheostomy, too. According to our present data, TLT seems to be an attractive and safe alternative to PDT. Nevertheless, for a definitive evaluation of TLT, further investigations in larger groups of patients and in the long term seem to be necessary.

Critical Care↗

PubMed1999

Tracheostomy in cardiosurgical patients: surgical tracheostomy versus ciaglia and fantoni methods.

BACKGROUND: Patients requiring prolonged mechanical ventilation are not uncommon in a cardiosurgical intensive care unit. Elective tracheostomy is considered the airway treatment of choice in these patients. METHODS: To evaluate different techniques for tracheostomy, we prospectively investigated 120 patients who had conventional open (n = 40), minimally invasive percutaneous dilatational (n = 40), or translaryngeal (n = 40) tracheostomy techniques. The main areas of investigation included oxygenation index (partial pressure of arterial oxygen divided by fraction of inspired oxygen), complications, infection, and cost. RESULTS: The oxygenation index decreased in almost every patient, regardless of the technique used, but the extent of decrease was significantly lower in both minimally invasive techniques compared with the conventional method. Overall complication rate was 12.5% both in open tracheostomy and in percutaneous dilatational tracheostomy, whereas no complications occurred in translaryngeal tracheostomy procedures. Bacterial contamination of the tracheostomy site was found in 35% of the open tracheostomies, whereas no infection was seen in percutaneous dilatational or translaryngeal tracheostomies. In terms of costs, PDT ($506) and TLT ($362) were both much cheaper than open tracheostomy ($699). CONCLUSIONS: Percutaneous dilatational and translaryngeal tracheostomies are safe and cost-effective procedures that can be done easily at the patient's bedside and thus are attractive alternatives to conventional surgical tracheostomy in long-term airway access in a cardiosurgical intensive care unit.

Adult↗

PubMed1999

Recovery and pharmacokinetic parameters of desflurane, sevoflurane, and isoflurane in patients undergoing urologic procedures.

STUDY OBJECTIVE: To compare the pharmacokinetics and the speed of recovery after inhalation anesthesia with desflurane, sevoflurane, and isoflurane in elective surgery. DESIGN: Prospective, randomized study. SETTING: University medical center. PATIENTS: 30 ASA physical status I and II adults presenting for elective surgery. INTERVENTIONS: Anesthesia was induced with etomidate and maintained with desflurane (n = 10), sevoflurane (n = 10), or isoflurane (n = 10) and nitrous oxide. The inhalation drugs were titrated until an adequate clinical depth of anesthesia was reached. At the end of anesthesia, the patients breathed oxygen via the endotracheal tube and after extubation via a face mask. MEASUREMENTS AND MAIN RESULTS: The groups were similar with respect to age, weight, duration of anesthesia, and mean arterial pressure. Mean end-tidal concentration (FA = FA0) at the end of anesthesia was 6.34 +/- 1.15% after desflurane, 1.85 +/- 0.42% after sevoflurane, and 1.10 +/- 0.24% after isoflurane. FA/FA0 decreased significantly faster with desflurane than with isoflurane, while there was little difference between desflurane and sevoflurane. As for the terminal half-life (t1/2), there were no differences among the groups (8.16 +/- 3.15 min after desflurane, 9.47 +/- 4.46 min after sevoflurane, and 10.0 +/- 5.57 min after isoflurane). The time until a command was followed for the first time was the same in all three groups (13.0 +/- 4.7 min after desflurane, 13.4 +/- 4.4 min after sevoflurane, and 13.6 +/- 3.4 min after isoflurane). There was no significant correlation between duration of anesthesia and the time until recovery. CONCLUSIONS: There are only minor differences with regard to the recovery phase in premedicated patients who receive clinically titrated inhalation anesthesia with desflurane, sevoflurane, or isoflurane.

Adolescent↗

PubMed1999

Percutaneous tracheostomy: a clinical comparison of dilatational (Ciaglia) and translaryngeal (Fantoni) techniques.

UNLABELLED: A number of percutaneous procedures for tracheostomy have been established within the last few years, among them a new technique by Fantoni using a translaryngeal approach for cannula placement. To compare the new translaryngeal tracheostomy (TLT) to the common percutaneous dilatational technique (PDT), we prospectively studied 90 patients who required elective tracheostomy. Tracheostomy was performed according to either the Ciaglia or the Fantoni technique in 45 patients at bedside. The overall complication rate was 11.1% (n = 5) in PDT, including aspiration of blood (n = 4) and severe bleeding requiring surgical intervention (n = 1). During TLT, there were technical difficulties involving guidewire placement in 31.1% (n = 14), and one patient required conversion to PDT. No other complications were noted in TLT. Regardless of the technique used, the postoperative PaO2/FIO2 ratio was slightly lower than preoperatively (P was not significant). When PDT and TLT were compared, the postoperative PaO2/FIO2 ratio was significantly lower in PDT than in TLT (P < 0.05), whereas the preoperative levels did not vary significantly between PDT and TLT. During TLT, the PaCO2 increased significantly, whereas it remained stable throughout PDT. No infection of the tracheostoma was noted in either the PDT or the TLT. We therefore consider both the PDT and the TLT equally safe and attractive techniques for establishing long-term airway access in critically ill patients. IMPLICATIONS: Elective tracheostomy is a widely accepted procedure for gaining long-term airway access. Two techniques for percutaneous tracheostomy-the established Ciaglia method and the new translaryngeal Fantoni technique-were prospectively studied for perioperative complications and practicability in 90 critically ill-patients.

Aged↗

PubMed1999

[Infection or SIRS--the problem of definition].

Despite the knowledge about sepsis for many years, the definition of sepsis is contested more than ever since the early 90th. Therefore, the comparability of many clinical investigations and scientific work in the past is still impaired. To define the entrance criteria for further clinical studies, in 1991 a consensus conference was held in the USA, but its recommendations have not found unequivocal acceptance. Therefore, these recommendations are presented and their meaning will be discussed.

Diagnosis, Differential↗

PubMed1998

The pharmacokinetics of acetyl starch as a plasma volume expander in patients undergoing elective surgery.

UNLABELLED: Acetyl starch (ACS) is a new synthetic colloid solution for plasma volume expansion and is now undergoing phase 2 clinical trials. We compared the pharmacokinetics of ACS with those of hydroxyethyl starch (HES) in 32 patients (ASA physical status I and II) undergoing elective surgery. In this randomized, double-blind trial, patients received either 15 mL/kg ACS 6% (average molecular weight [Mw] 200,000/molar substitution [MS] 0.5) or HES 6% (Mw 200,000/MS 0.5) i.v. up to a maximal dose of 1000 mL. Plasma colloid concentrations were measured by repetitive arterial blood sampling over 24.5 h. Plasma colloid concentrations were detected using a high-pressure liquid chromatography controlled enzymatic test. Standard pharmacokinetics were calculated, including initial half-life (t(1/2init)), i.e., the time required for a 50% decline of the maximal plasma colloid concentration at the end of drug infusion. Whereas HES was eliminated by second-order kinetics, ACS followed first-order characteristics. In the first hours after i.v. administration, t(1/2init) and clearances were similar in both groups. However, the terminal half-life of HES was significantly longer than that of ACS (9.29 +/- 1.43 h vs 4.37 +/- 1.06 h). After 16.5 and 24.5 h, ACS showed significantly lower plasma concentrations than HES, which indicates that the final degradation of ACS by esterases and amylase was significantly more rapid. ACS might be an alternative plasma volume expander, which avoids the accumulation of persisting macromolecules. IMPLICATIONS: We studied the pharmacokinetics of acetyl starch, a newly developed colloid solution for plasma volume substitution, compared with hydroxyethyl starch in 32 surgical patients undergoing elective major general surgical procedures. In contrast to hydroxyethyl starch, this new agent undergoes rapid and nearly complete enzymatic degradation.

Adolescent↗

PubMed1998

Thoracoscopic microsurgical technique for vertebral surgery--anesthetic considerations.

BACKGROUND: The thoracoscopic microsurgical technique (TMT) for vertebral and spinal cord surgery is associated with the benefits of reduced postoperative pain, accelerated return to physical activity and reduced complication rates. However, because of the surgeon's requirement of a non-ventilated lung, it confronts the anesthesiologist with the need for extremely long duration of single-lung ventilation (SLV). METHODS: We describe our experiences with 82 patients, whom we anesthetised from 1993 until 1996 for TMT. Because of the potential risk of depression of hypoxic pulmonary vasoconstriction during SLV by volatile anesthetics, we primarily used a total intravenous technique (55 patients). With more experience, we also used a combination of volatile and intravenous anesthetics (16 patients) and, finally, volatile anesthetics only (11 patients). Data from patients anesthetised for TMT were compared with data from 22 patients operated with open thoracotomy from 1984 until 1992. RESULTS: While the operating time (290.1 +/- 133.2 min for TMT vs. 312.3 +/- 113.6 for thoracotomy) and the anesthesia time (431.2 +/- 140.3 for TMT vs. 416.4 +/- 102.1 for thoracotomy) showed no significant differences, the TMT required an extremely long time of SLV (270.2 +/- 133.2 min) to gain access to the spine using left-sided double-lumen tubes. While the oxygenation index (PaO2/FiO2), as a marker for pulmonary oxygenation capacity, decreased significantly after initiation of SLV for TMT, it was markedly enhanced with increasing duration (270.2 +/- 133.2 min) of SLV. Oxygenation index showed no significant difference when comparing the different anesthetic techniques for TMT. CONCLUSION: We conclude that despite the long duration of SLV, TMT is a reasonable alternative to open thoracotomy for thoracic neurosurgical spine procedures because of the substantial clinical benefits of accelerated return to physical activity, reduced complication rates and reduced intensive care unit and hospital stay.

Activities of Daily Living↗

PubMed1998

[Exposure of recovery room personnel to inhalation anesthetics].

Both desflurane and sevoflurane have a favourable blood/gas distribution coefficient. There is concern, however, that environmental contamination is higher when these agents are employed since they must be used in relatively high concentrations. Our study seeks to determine the degree of exposure of recovery room staff to trace amounts of these two agents. Two hundred and seven surgical patients were included in the study. The recovery room studied had a volume of 243 cubic metres. The hourly fresh air supply for this room was 1,845 cubic metres, which results in 7.6 air exchanges per hour without air return. Measurements of trace concentrations of the inhalational agents were taken for 12 days. Concentrations of these anaesthetics were assessed in the recovery room with a real-time infrared spectrometer every 90 seconds. Mean exposure to nitrous oxide in the recovery room was 11.5 +/- 3.97 ppm and to isoflurane 1.4 +/- 0.31 ppm. All measured values were below the standard German threshold values. Trace concentrations of desflurane were 2.8 +/- 0.84 ppm and of sevoflurane 3.2 +/- 0.62 ppm. We conclude that the exposure to the inhalational anaesthetics in the climatised recovery room was low. The threshold values of 100 ppm for nitrous oxide and 10 ppm for isoflurane recommended by German law were not exceeded. When the new volatile anaesthetics are used, exposure of recovery room staff to trace concentrations of these agents is higher, but the concentrations do not exceed the levels allowed applicable German health regulations.

Air Pollutants, Occupational↗

PubMed1997

[Anesthetics and nitric oxide. Interactions and their importance for anesthesia].

Due to its important physiological and pathophysiological actions, the pluripotent signaling molecule nitric oxide (NO) is increasingly of interest in clinical medicine. Despite increasing use by anaesthetists in inhalational therapy for intensive care patients with respiratory distress syndrome, the potential interactions of anaesthetic agents and NO have thus far received little attention. The literature available to date on this topic is somewhat controversial, and highlights the need for additional research in this area. This review summarises the pertinent literature in this area for the anaesthetist and describes potential mechanisms by which anaesthetics may interfere with the synthesis and/or effects of NO in the human body.

Anesthesia↗

PubMed1997

Heparin-induced thrombocytopenia type II: perioperative management using danaparoid in a coronary artery bypass patient with renal failure.

An 84-year-old patient with heparin-induced thrombocytopenia (HIT), global cardiac decompensation, and acute renal failure underwent a cardiosurgical intervention using an extracorporeal circuit. For systemic anticoagulation danaparoid (Orgaran) was applied as a heparin substitute preoperatively and maintained for systemic anticoagulation during ECC despite it being eliminated by the kidney. The postoperative recovery was prolonged due to bleeding complications. During cardiopulmonary bypass (216 min) the target level of anti-factor Xa was 1.5 UI/ml. This required continuous infusion and an occasional bolus of danaparoid. Coagulation in the extracorporeal circuit was observed twice at plasma levels below 1.4 IU/ml. There were no thromboembolic or neurologic events. We did not retransfuse blood from the extracorporeal circuit or the cardiotomy reservoir after bypass, but because elimination of danaparoid was impaired in this patient and there is no neutraliser available antifactor Xa postoperatively exceeded 0.6 IU/ml for 30 hours. Diffuse bleeding with tamponade resulted. Weaning the patient from the respirator was achieved 12 hours after the last re-exploration. From the 4th postoperative day 750 IU of danaparoid were administered twice daily subcutaneously for thrombosis prevention. On the 6th postoperative day discharge from the ICU was possible. We conclude that the application of danaparoid for cardiopulmonary bypass in patients suffering from acute renal failure may be complicated by hemorrhage.

Acute Kidney Injury↗

PubMed1997

[Exposure of the pediatric surgeon to inhalation-anesthetic during pediatric bronchoscopy procedures].

BACKGROUND: General anaesthetic agents are frequently used for paediatric bronchoscopy. A disadvantage of this open system anaesthesia seems to be the contamination of the working environment. The aim of this study was to determine the exposure of the endoscopist during paediatric bronchoscopy under general anaesthesia in different working environments and to compare these measurements with the currently valid international threshold limit values. MATERIAL AND METHODS: 25 children (ASA I-III) scheduled for diagnostic bronchoscopy were included in the study. After inhalational induction all children were intubated with a nonflexible bronchoscope and manually ventilated through a side arm of the bronchoscope. Maintenance of anaesthesia was achieved with sevoflurane (2-3 vol%) in 80% oxygen. Trace concentrations were measured every 90 seconds in the breathing zones of the paediatrician by means of a highly sensitive direct-reading instrument (Brüel & Kjaer 1302). The lower detection limit was 0.02 ppm. The investigation was done in an OT with and without air conditioning and scavening system. RESULTS: The mean age of the children was 50.3 months (range: 3-109 months). Ventilation and oxygenation were stable throughout the bronchoscopic procedure. Mean exposure of the paediatrician without air-conditioning and scavening system to sevoflurane was over 50 ppm for the endoscopist. All international threshold limit values were exceeded. Peak concentrations higher than 100 ppm sevoflurane were detected repeatedly in 40% of anaesthesias. During bronchoscopy in the operating room equipped with laminar air flow (20.2 air exchanges per hour) and narcotic gas evacuation (30 l/min) the mean exposure of the paediatrician was 26.4 ppm sevoflurane. CONCLUSIONS: The main finding of the present study is that under inhalation anaesthesia with sevoflurane for paediatric bronchoscopy occupation exposure is higher than the limits stated in all known health regulation guidelines. Therefore, in case of such working conditions, the use of total intravenous anaesthesia is advocated also in very small infants.

Adult↗

PubMed1996

[Repeated addition of fentanyl to bupivacaine peridural analgesia in labor. Clinical action and fentanyl plasma level].

A combination of epidural opioids with local anaesthetics has been used to improve pain relief during labor and to reduce side effects, such as muscle weakness, usually seen when local anaesthetics are used alone. The addition of epidural fentanyl (F) produces highly effective analgesia, the only side effect being mild itching. Initial trials investigated the improvement in analgesia after a single administration of F during first- but not during second-stage labor. Even though pain perception during second-stage labor under epidural analgesia with local anaesthetics can be severe, the addition of opioids was avoided for fear of neonatal or maternal depression. A recent report found maternal and umbilical plasma concentrations following injection of 100 micrograms F to be safe and the investigators speculated that repeated addition of epidural/F to injection of local anaesthetic may prove beneficial for the parturient without exposing the mother or fetus to risk. We therefore studied maternal analgesia, maternal and umbilical plasma levels and associated side effects following repeated addition of 100 micrograms F to bupivacaine epidural analgesia during labor. METHODS. Following institutional and governmental approval 53 parturients were randomly assigned to receive either 8 ml bupivacaine 0.25% + 0.1 mg fentanyl (B + F group; n = 28) or 8 ml bupivacaine 0.25% + 2 ml saline (BUP group; n = 25) in an epidural catheter at L2/3. The same dose was reinjected upon the patients' request regardless of the degree of cervical dilatation. Blood pressure, heart rate, respiratory rate and the incidence of side effects were recorded before and following each epidural injection. Pain relief was determined at each injection and following cord clamping using the visual analogue pain scale (VAS; 0-100 mm). Maternal venous blood samples were collected to measure plasma F concentrations before and 20 and 40 min after each injection and at birth when umbilical venous and arterial blood was obtained. After centrifugation the samples were maintained at -20 degrees C and then analyzed by radioimmunoassay. At delivery, Apgar scores and umbilical venous and arterial blood gas values were determined. RESULTS. Both groups were comparable for age, weight, height, gestational age and parity. A total of 48 epidural injections were evaluated in the B + F group, 43 in the BUP group. No statistically significant group difference was found between the frequency of injections per delivery (B + F: 2.2; BUP: 1.8); regarding the time between the initial and the first top-up dose (B + F: 144 min; BUP: 140 min) or regarding the interval between the last injection and birth (B + F: 94 min; BUP; 90 min). However, the quality of pain relief during labor and particularly at birth was significantly improved by F (mean VAS in B + F group: 6 mm; mean VAS in BUP group: 42 mm). Mild itching was observed in 43% of patients receiving F, moderate shivering in 13% versus 40% in patients not receiving F. At control mean maternal F plasma levels were not zero but 0.25 ng/ml. After the initial injection and following the first and second top-up dose mean maximum maternal F plasma concentrations were 0.54 ng/ml (+/-0.32; +/-SD), 0.88 ng/ml (+/-0.62) and 1.06 ng/ml (+/-0.4) (range 0.18-2.76 ng/ml), respectively. The increase in maternal F concentrations with increasing injection frequency was statistically significant (P < 0.02). Mean umbilical venous and arterial F concentrations at birth were 0.72 ng/ml (+/-1.16) and 0.62 ng/ml (+/-0.52). No significant group differences were found regarding Apgar scores or umbilical blood gas analyses. In one newborn, radioimmunoassay resulted in unexplainably high umbilical F concentrations without any clinical signs of sedation, depressed vigilance and without any sequellae. DISCUSSION. Repeated addition of 100 micrograms F to epidural anaesthesia with bupivacaine significantly improves analgesia and provides pain relief not only during the fir

Adult↗

PubMed1996

Etomidate and thiopental inhibit the release of endothelium-derived hyperpolarizing factor in the human renal artery.

BACKGROUND: Endothelium-derived hyperpolarizing factor is thought to be a cytochrome P450-derived arachidonic acid metabolite that hyperpolarizes vascular smooth muscle cells by opening Ca(2+)-activated K+ channels (K+Ca channels). In the rabbit carotid artery both volatile and intravenous anesthetics inhibit the acetylcholine-stimulated release of endothelium-derived hyperpolarizing factor. Because the release of this factor may help to maintain vascular tone in humans under conditions of a failing nitric oxide synthesis, e.g., in atherosclerosis, the effects of two intravenous anesthetics, thiopental and etomidate, on the endothelium-derived hyperpolarizing factor-mediated relaxant response to acetylcholine were investigated in human isolated renal artery segments. METHODS: The segments were suspended in Krebs-Henseleit solution (37 degrees C) containing the cyclooxygenase inhibitor diclofenac (1 microM) and preconstricted with norepinephrine (6 microM). Relaxations caused by acetylcholine (1 microM) were compared in the presence and absence of the nitric oxide synthase inhibitor N(G)-nitro-L-arginine (0.1 mM) in control segments and in segments exposed to etomidate or thiopental (0.03-0.3 mM). In addition, the effects of the two anesthetics on the relaxant response to the nitric oxide donors glyceryl trinitrate (3 microM) and sodium nitroprusside (0.1 microM) were examined. RESULTS: The relaxant response to acetylcholine, which was resistant to both nitric oxide synthase and cyclooxygenase blockade, was markedly reduced by the K+Ca channel antagonist tetrabutyl ammonium (3 mM) and the cytochrome P450 inhibitor clotrimazole (30 microM). Both etomidate and thiopental, at a concentration of 0.3 mM, selectively attenuated the relaxant response to acetylcholine in N(G)-nitro-L-arginine-treated segments, but did not affect relaxations elicited by glyceryl trinitrate or sodium nitroprusside. CONCLUSIONS: Etomidate and thiopental inhibit the endothelium-derived hyperpolarizing factor-mediated relaxant response to acetylcholine in the human renal artery, an effect that appears to be attributable to the cytochrome P450-inhibiting properties of these anesthetics.

Anesthetics, Intravenous↗

PubMed1995

Volatile and intravenous anesthetics selectively attenuate the release of endothelium-derived hyperpolarizing factor elicited by bradykinin in the coronary microcirculation.

In addition to nitric oxide (NO) and prostacyclin (PGI2) another endothelium-derived factor, which hyperpolarizes vascular smooth muscle cell via activation of K+ channels, contributes to the vasorelaxant effect of bradykinin in different vascular beds. Preliminary findings suggest that this endothelium-derived hyperpolarizing factor (EDHF)-mediated vasodilatation is attenuated by both volatile and intravenous anesthetics. Since EDHF may play an important role in the coronary microcirculation, we investigated the effects of isoflurane (2 vol.% equivalent to approximately 250 microM), etomidate (30 and 100 microM), phenobarbital (100 microM) and thiopental (30 and 100 microM) on the EDHF-mediated dilator response to bradykinin and on the endothelium-independent dilatation evoked by sodium nitroprusside (SNP) in the isolated saline-perfused rat heart (Langendorff preparation). None of the anesthetics tested affected the dilator response to bradykinin or SNP under basal conditions. However, following inhibition of NO and PGI2 formation with NG-nitro-L-arginine (100 microM) and diclofenac (1 microM) respectively, isoflurane, etomidate and thiopental, but not phenobarbital, significantly attenuated the NO/PGI2-independent, i.e. EDHF-mediated dilator response to bradykinin, while the vasorelaxant effect of SNP remained unaffected. Isoflurane, etomidate and thiopental, but not phenobarbital, display cytochrome P450-inhibiting properties, suggesting that these anesthetics impair the cytochrome P450-dependent synthesis of EDHF in the coronary microcirculation.

Analysis of Variance↗