Claudia Höhne

Opioide in der Anästhesie bei Leber- und Niereninsuffizienz

ZusammenfassungDie Pharmakokinetik der in Anästhesie und Intensivmedizin verwendeten Opioide ist bei eingeschränkter Leber- und Nierenfunktion verändert. Fentanyl, Sufentanil, Alfentanil und Piritramid unterliegen der hepatischen Metabolisierung, ihre extrahepatische Metabolisierung ist bei Leberfunktionsstörung bedeutsam. Nach Einzeldosen von Fentanyl und Sufentanil ist deren Pharmakokinetik bei Leber- oder Nierenfunktionsstörungen nicht verändert. Dagegen kann die kontinuierliche Gabe von Fentanyl zur Akkumulation und Wirkungsverlängerung bei Niereninsuffizienz führen. Alfentanil hat eine eingeschränkte Clearance und Elimination bei Lebererkrankung und sollte daher bei Leberinsuffizienz vermieden werden. Bei Nierenerkrankungen ist hingegen keine Dosisanpassung von Alfentanil erforderlich. Remifentanil kann bei Leber- und Niereninsuffizienz ohne Dosisanpassung verwendet werden. Die Clearance von Morphin ist bei schweren Lebererkrankungen deutlich reduziert, bei ausgeprägter Nierenfunktionsstörung kommt es zur Akkumulation der Metabolite. Es empfiehlt sich daher der Verzicht der Substanz bei Leber- und Niereninsuffizienz. Piritramid muss bei Leberinsuffizienz dosisangepasst werden.AbstractThe pharmacokinetics of opioids are impaired in patients with liver and renal failure. Fentanyl, sufentanil, and alfentanil are metabolized in the liver. The extrahepatic metabolism by renal enzymes is gaining more importance in patients with severe liver disease. Pharmacokinetic effects of single doses of fentanyl and sufentanil are not affected in liver and renal failure; however, continuous infusion of fentanyl may result in accumulation and prolonged opioid effects. Plasma clearance and elimination of alfentanil are reduced in patients with liver failure and its clinical use can therefore not be recommended. A reduction in alfentanil dosing is not necessary in patients with renal failure. Remifentanil is the opioid of choice in patients with liver and renal failure. The clearance of morphine is reduced in liver failure. In renal failure an accumulation of morphine metabolites has been demonstrated, and thus, application of morphine is not recommended in patients with liver and renal failure. A reduction in piritramide dosing is necessary in patients with liver failure.

Ultrasound‐guided central venous cannulation in a very small preterm neonate

Percutaneous central venous cannulation of small infants is a challenging procedure. The use of ultrasound guidance has been shown to increase the success rate generally in children and to decrease the incidence of associated complications. To demonstrate that this technique is also suitable in very small infants we describe the case of a preterm neonate of 850 g body weight (BW), in which percutaneous central venous cannulation was performed successfully using ultrasound imaging for guidance.

ACE inhibition does not exaggerate the blood pressure decrease in the early phase of spinal anaesthesia

Background:  This study investigates whether long‐term treatment with an angiotensin converting enzyme inhibitor (ACEI) impairs the hemodynamic regulation during the early phase of spinal anaesthesia.

The haemodynamic and catecholamine response to xenon/remifentanil anaesthesia in Beagle dogs

The noble gas xenon seems to have minimal cardiovascular side-effects and so may be an ideal anaesthetic agent when investigating cardiovascular physiology. In comparison with standard modern anaesthetics, we investigated the haemodynamic and hormonal effects of xenon in Beagle dogs. After a 30 min baseline period, anaesthesia was induced with propofol and maintained with either (1) 1.2% isoflurane/70% nitrous oxide (N2O), (2) 0.8% isoflurane/0.5 µg/kg/min remifentanil or (3) 63% xenon/0.5 µg/kg/min remifentanil (n = 6 per group). Haemodynamics were recorded and blood samples taken before and 60 min after induction. Mean arterial blood pressure (MAP) was higher in conscious dogs than during isoflurane/N2O (86 ± 2 vs. 65 ± 2 mmHg, mean ± SEM) and isoflurane/remifentanil anaesthesia (95 ± 2 vs. 67 ± 3 mmHg), whereas MAP did not decrease significantly in response to xenon/remifentanil anaesthesia (96 ± 4 vs. 85 ± 6 mmHg). Bradycardia was present during isoflurane/remifentanil (54 ± 2/min) and xenon/remifentanil (40 ± 3/min), but not during isoflurane/N2O anaesthesia (98 ± 3/min, P < 0.05). Xenon/remifentanil anaesthesia induced the highest reduction in cardiac output (CO) (–61%), and the highest increase in systemic vascular resistance (+120%) among all treatment groups (P < 0.05). A simultaneous increase in endogenous adrenaline and noradrenaline concentrations could only be observed in the xenon/remifentanil group, whereas angiotensin II and vasopressin concentrations increased in all groups. In conclusion, xenon/remifentanil anaesthesia maintains MAP but reduces heart rate and CO and is associated with a considerable stimulation of vasopressor hormones in Beagle dogs. Therefore, xenon/remifentanil exerts a new quality of adverse haemodynamic effects different from volatile anaesthetics and may not perform better during studies of cardiovascular physiology.

Perioperative intravenous fluid therapy in children: guidelines from the Association of the Scientific Medical Societies in Germany

This consensus‐ based S1 Guideline for perioperative infusion therapy in children is focused on safety and efficacy. The objective is to maintain or re‐establish the childs normal physiological state (normovolemia, normal tissue perfusion, normal metabolic function, normal acid‐ base‐ electrolyte status). Therefore, the perioperative fasting times should be as short as possible to prevent patient discomfort, dehydration, and ketoacidosis. A physiologically composed balanced isotonic electrolyte solution (BS) with 1–2.5% glucose is recommended for the intraoperative background infusion to maintain normal glucose concentrations and to avoid hyponatremia, hyperchloremia, and lipolysis. Additional BS without glucose can be used in patients with circulatory instability until the desired effect is achieved. The additional use of colloids (albumin, gelatin, hydroxyethyl starch) is recommended to recover normovolemia and to avoid fluid overload when crystalloids alone are not sufficient and blood products are not indicated. Monitoring should be extended in cases with major surgery, and autotransfusion maneuvers should be performed to assess fluid responsiveness.

Detection of catecholamines and metanephrines by radio-immunoassay in canine plasma

This study investigated the applicability of two human radio-immunoassays (RIA) to detect epinephrine (EPI), norepinephrine (NE), and their O-methylated metabolites metanephrine (MN) and normetanephrine (NMN) in canine plasma. The analysis yielded a positive correlation between metabolites and their respective parent compounds: EPI and MN (r=0.63), NE and NMN (r=0.47), as well as between parent compounds, EPI and NE (r=0.48), and between metabolites MN and NMN (r=0.71). Moreover, EPI (r=0.99) and NE (r=0.77) concentrations determined by RIA did correlate positively with high pressure liquid chromatography (HPLC). However, there was limited agreement between both methods. It was concluded that complete validation tests for accuracy, precision and agreement are needed before this RIA can be applied to quantify catecholamines, metanephrine, and normetanephrine in canine plasma. The assay may prove to be a potential alternative to HPLC or tandem mass spectrometry in the work-up of pheochromocytoma and the detection of overall sympathetic activity in dogs.

Haemodynamic and hormonal changes during haemorrhage in conscious dogs treated with an endothelin-A receptor antagonist

This study compares the haemodynamic and hormonal responses during haemorrhage of conscious dogs pre-treated with an endothelin-A (ET-A) receptor inhibitor. The dogs were studied in two different randomized groups: the control group and a group that was given the ET-A receptor antagonist ABT-627 (as a bolus of 1 mg x kg of body weight(-1) followed by 0.01 mg x kg body weight(-1) x min(-1) intravenously). The time-course was the same for both groups: after a 1 h baseline period (pre-haemorrhage), blood (25 ml x kg of body weight(-1)) was withdrawn within 5 min. Haemodynamics were continuously recorded and hormone levels measured after 1 h (post-haemorrhage). Thereafter, the blood withdrawn was retransfused within 5 min and haemodynamics again observed for 1 h (post-retransfusion). In ABT-627-treated dogs, the decrease in mean arterial pressure from 87+/-3 to 64+/-3 mmHg (P<0.05 versus pre-haemorrhage), and cardiac output from 2.1+/-0.1 to 1.3+/-0.1 l x min(-1) (P<0.05 versus pre-haemorrhage) and the increase in systemic vascular resistance from 3286+/-174 to 4211+/-230 dyn.s.cm(-5) (P<0.05 versus pre-haemorrhage) during acute haemorrhage are comparable with controls. During haemorrhage in controls, vasopressin levels increased from 0+/-0 to 13+/-2 pg x ml(-1) (P<0.05 versus pre-haemorrhage), angiotensin II levels increased from 9+/-1 to 28+/-9 pg x ml(-1) (P<0.05 versus pre-haemorrhage) and adrenaline levels increased from 134+/-22 to 426+/-74 pg x ml(-1) (P<0.05 versus pre-haemorrhage) whereas noradrenaline levels did not change (approx. 200 pg x ml(-1)). In ABT-627-treated dogs, vasopressin levels increased from 0.2+/-0.0 to 22.2+/-6.1 pg x ml(-1) (P<0.05 versus pre-haemorrhage and P<0.05 versus control), angiotensin II levels increased from 8+/-1 to 37+/-8 pg x ml(-1) (P<0.05 versus pre-haemorrhage), noradrenaline levels increased from 147+/-16 to 405+/-116 pg x ml(-1) (P<0.05 versus pre-haemorrhage) and adrenaline levels did not change (200 pg x ml(-1)) during haemorrhage. We conclude from our results that dogs receiving the selective ET-A inhibitor ABT-627 seem to show a different hormonal response after haemorrhage compared with controls, displaying considerably higher noradrenaline concentrations. Independent of ET-A receptor inhibition, cardiac output during haemorrhage was maintained within the control range. This may indicate that the organism is defending blood flow (cardiac output) over blood pressure during haemorrhage, and that this defence strategy is not compromised by ET-A receptor inhibition.

Anesthesia in an infant with uncorrected tetralogy of Fallot for transanal pull-through for Hirschsprung's disease

1 Bordet F, Allaouchiche B, Lansiaux S et al. Risk factors for airway complications during general anaesthesia in paediatric patients. Paediatr Anaesth 2002; 12: 762–769. 2 Kuvaki Balkan B, Günenç F, Iyilikçi L et al. The laryngeal mask airway (LMA) in paediatric ophthalmic anaesthesia practice. Eur J Anaesthesiol (in press). 3 Tait AR, Pandit UA, Voepel-Lewis T et al. Use of the laryngeal mask airway in children with upper respiratory tract infections: a comparison with endotracheal intubation. Anesth Analg 1998; 86: 706–711. 4 Keller C, Brimacombe J. Bronchial mucus transport velocity in paralyzed anesthetized patients: a comparison of the laryngeal mask airway and cuffed tracheal tube. Anesth Analg 1998; 86: 1280–1282. 5 Gebhard R, Pivalizza EG, Nasri S et al. Bilateral intraoperative atelectasis in a child with latex allergy. Anesthesiology 2000; 93: 1147–1149. 6 Caudwell CB Induction, maintenance, and emergence. In: Gregory GA III, ed. Pediatric Anesthesia. New York: Churchill Livingstone, 1994: 227–260.

Pediatric resuscitation. Current guidelines and treatment recommendations

Cardiopulmonary resuscitation of a child is a rare, emotionally affective, challenging and potentially frightful event. Current guidelines have been largely simplified to facilitate teaching and retention, to encourage bystander resuscitation, and to improve the quality of resuscitation by healthcare professionals. This article is a practical approach to the current european guidelines (ERC), including basic and advanced life support algorithms, as well as recommendations on the post-resuscitation periode and parental presence.

The effect of intraoperative administration of dexamethasone for PONV prophylaxis on perioperative blood glucose level in obese and normal weight children.

Abstract Background: The incidence of postoperative nausea and vomiting (PONV) can be reduced by dexamethasone. Single-dose administration may cause elevated blood glucose levels in obese adults. No data are available for children. Objective: The aim was to evaluate perioperative blood glucose changes related to body weight in children who received dexamethasone. Patients and methods: This prospective observational study included 62 children. All patients received total intravenous anesthesia and a single dose of dexamethasone (0.15 mg/kg, maximum 8 mg). Blood glucose levels were measured up to 6 h. Standard deviation scores (SDS) were calculated using age- and gender-specific body mass index (BMI) percentiles, p<0.05. Results: A total of 62 children (11.5±2.9 years, median SDS 0.43, 29% overweight/obese) were included. Blood glucose levels increased from 5.52±0.52 to 6.74±0.84 mmol/L 6 h after dexamethasone without correlation to the BMI-SDS. Conclusions: This study showed an increase of perioperative blood glucose (normoglycemic ranges) after single dose of dexamethasone, but no BMI-dependent effect was observed in children. Therefore, low-dose dexamethasone may be used in obese children for PONV prophylaxis.