Management der oberen Atemwege beim spontan atmenden Kind: Eine Herausforderung für den Anästhesisten

Zusammenfassung: Partielle und totale Atemwegsobstruktionen treten bei spontan atmenden, bewusstlosen oder anästhesierten Kindern häufig auf und können eine adäquate Sauerstoffversorgung gefährden. Das Offenhalten der oberen Atemwege ist daher die wichtigste und effektivste Maßnahme in dieser Situation: Kinn hochheben ("chin lift"), Unterkiefer nach vorne verschieben ("jaw thrust", Esmarch-Handgriff) und kontinuierlich positiver Atemwegsdruck ("continuous positive airway pressure", CPAP) öffnen nachgewiesenermaßen den Atemweg. Neben diesen einfachen Atemwegsmanövern führen auch verschiedene Lagerungstechniken (Seitenlage oder Rückenlage unter Einnahme der "Schnüffelposition") zu einer besseren Öffnung und Stabilität des oberen Atemweg

Effect of obesity and thoracic epidural analgesia on perioperative spirometry

Background. Lung volumes in obese patients are reduced significantly in the postoperative period. As the effect of different analgesic regimes on perioperative spirometric tests in obese patients has not yet been studied, we investigated the effect of thoracic epidural analgesia and conventional opioid-based analgesia on perioperative lung volumes measured by spirometry. Methods. Eighty-four patients having midline laparotomy for gynaecological procedures successfully completed the study. Premedication, anaesthesia and analgesia were standardized. The patients were given a free choice between epidural analgesia (EDA) (n=42) or opioids (n=42) for postoperative analgesia. We performed spirometry to measure vital capacity (VC), forced vital capacity, peak expiratory flow, mid-expiratory flow and forced expiratory volume in 1 s at preoperative assessment, 30-60 min after premedication and 20 min, 1 h, 3 h and 6 h after extubation. Results. Baseline values were all within the normal range. All perioperative spirometric values decreased significantly with increasing body mass index (BMI). The greatest reduction in VC occurred directly after extubation, but was less in the EDA group than in the opioid group: mean of −23(sd 8)% versus −30(12)% (P30) the difference in VC was significantly more pronounced than in patients of normal weight (BMI<25): −45(10)% versus −33(4)% (P<0.001). Recovery of spirometric values was significantly quicker in patients receiving EDA, particularly in obese patients. Conclusion. We conclude that EDA should be considered in obese patients undergoing midline laparotomy to improve postoperative spirometr

Effect of obesity and site of surgery on perioperative lung volumes

Background. Although obese patients are thought to be susceptible to postoperative pulmonary complications, there are only limited data on the relationship between obesity and lung volumes after surgery. We studied how surgery and obesity affect lung volumes measured by spirometry. Methods. We prospectively studied 161 patients having either breast surgery (Group A, n=80) or lower abdominal laparotomy (Group B, n=81). Premedication and general anaesthesia were standardized. Spirometry was measured with the patient supine, in a 30° head‐up position. We measured vital capacity (VC), forced vital capacity, peak expiratory flow and forced expiratory volume in 1 s at preoperative assessment (baseline), after premedication (before induction of anaesthesia) and 10-20 min, 1 h and 3 h after extubation. Results. Baseline spirometric values were all within the normal range. All perioperative values decreased significantly with increasing body mass index (BMI). The greatest reduction of mean VC (expressed as percentage of baseline values) occurred after extubation, and was more marked after laparotomy than after breast surgery (23 (sd 14)% vs 20 (14)%). Considering patients according to BMI (30), VC decreased after surgery by 12 (7)%, 24 (8)% and 40 (10)%, respectively. VC recovered more rapidly in Group A. Conclusion. Postoperative reduction in spirometric volumes was related to BMI. Obesity had more effect on VC than the site of surgery. Br J Anaesth 2004; 92: 202-

Impact of depth of propofol anaesthesia on functional residual capacity and ventilation distribution in healthy preschool children

Background Propofol is commonly used in children undergoing diagnostic interventions under anaesthesia or deep sedation. Because hypoxaemia is the most common cause of critical deterioration during anaesthesia and sedation, improved understanding of the effects of anaesthetics on pulmonary function is essential. The aim of this study was to determine the effect of different levels of propofol anaesthesia on functional residual capacity (FRC) and ventilation distribution. Methods In 20 children without cardiopulmonary disease mean age (sd) 49.75 (13.3) months and mean weight (sd) 17.5 (3.9)kg, anaesthesia was induced by a bolus of i.v. propofol 2mgkg−1 followed by an infusion of propofol 120µgkg−1min−1 (level I). Then, a bolus of propofol 1mgkg−1 was given followed by a propofol infusion at 240µgkg−1min−1 (level II). FRC and lung clearance index (LCI) were calculated at each level of anaesthesia using multibreath analysis. Results The FRC mean (sd) decreased from 20.7 (3.3)mlkg−1 at anaesthesia level I to 17.7 (3.9)mlkg−1 at level II (P < 0.0001). At the same time, mean (sd) LCI increased from 10.4 (1.1) to 11.9 (2.2) (P = 0.0038), whereas bispectral index score values decreased from mean (sd) 57.5 (7.2) to 35.5 (5.9) (P < 0.0001). Conclusions Propofol elicited a deeper level of anaesthesia that led to a significant decrease of the FRC whereas at the same time the LCI, an index for ventilation distribution, increased indicating an increased vulnerability to hypoxaemi

Export Production, Hedging Exchange Rate Risk: The Duopoly Case

This paper studies a Cournot duopoly in international trade so that the firms are exposed to exchange rate risk. A hedging opportunity is introduced by a forward market where the foreign currency can be traded on. We investigate two settings: First we assume that hedging and output decisions are taken simultaneously. We show that hedging is just done for risk managing reasons as it is not possible to use hedging strategically. In this setting the well-known separation result of the competitive firm holds if both firms have the hedging opportunity. In the second setting the hedging decisions are made before the output decisions. We show that hedging is used not only to manage the risk exposure but also as a strategic device. Furthermore we find that no separation result can be stated