Oliver Kimberger

Tissue oxygenation in obese and non-obese patients during laparoscopy

Background: Wound infection risk is inversely related to subcutaneous tissue oxygenation, which is reduced in obese patients and may be reduced even more during laparoscopic procedures. Methods: We evaluated subcutaneous tissue oxygenation (PsqO2) in 20 patients with a body mass index (BMI) ≥40 kg/m2 (obese group) and 15 patients with BMI <30 kg/m2 (non-obese group) undergoing laparoscopic surgery with standardized anaesthesia technique and fluid administration. Arterial oxygen tension was maintained near 150 mmHg. PsqO2 was measured from a surrogate wound on the upper arm. Results: A mean FIO2 of 51% (13%) was required in obese patients to reach an arterial oxygen tension of 150 mmHg; however, a mean FIO2 of only 40% (7%) was required to reach the same oxygen tension in non-obese patients (P=0.007). PsqO2 was significantly less in obese patients: 41 (10) vs 57 (15) mmHg (P<0.001). Conclusion: Obese patients having laparoscopic surgery require a significantly greater FIO2 to reach an arterial oxygen tension of about 150 mmHg than non-obese patients; they also have significantly lower subcutaneous oxygen tensions. Both factors probably contribute to an increased infection risk in obese patients.

Local warming and insertion of peripheral venous cannulas: single blinded prospective randomised controlled trial and single blinded randomised crossover trial

Abstract Objective: To determine whether local warming of the lower arm and hand facilitates peripheral venous cannulation. Design: Single blinded prospective randomised controlled trial and single blinded randomised crossover trial. Setting: Neurosurgical unit and haematology ward of university hospital. Participants: 100 neurosurgical patients and 40 patients with leukaemia who required chemotherapy. Interventions: Neurosurgical patients hands and forearms were covered for 15 minutes with a carbon fibre heating mitt. Patients were assigned randomly to active warming at 52°C or passive insulation (heater not activated). The same warming system was used for 10 minutes in patients with leukaemia. They were assigned randomly to active warming or passive insulation on day 1 and given alternative treatment during the subsequent visit. Main outcome measures: Primary: success rate for insertion of 18 gauge cannula into vein on back of hand. Secondary: time required for successful cannulation. Results: In neurosurgical patients, it took 36 seconds (95% confidence interval 31 to 40 seconds) to insert a cannula in the active warming group and 62 (50 to 74) seconds in the passive insulation group (P=0.002). Three (6%) first attempts failed in the active warming group compared with 14 (28%) in the passive insulation group (P=0.008). The crossover study in patients with leukaemia showed that insertion time was reduced by 20 seconds (8 to 32, P=0.013) with active warming and that failure rates at first attempt were 6% with warming and 30% with passive insulation (P<0.001). Conclusions: Local warming facilitates the insertion of peripheral venous cannulas, reducing both time and number of attempts required. This may decrease the time staff spend inserting cannulas, reduce supply costs, and improve patient satisfaction.

Nitrous oxide increases the incidence of bowel distension in patients undergoing elective colon resection

Background:u2002 Nitrous oxide rapidly inflates gas‐filled spaces such as the intestines; but whether the resulting bowel distension is clinically important remains unclear. We therefore tested the hypothesis that nitrous oxide produces clinically important bowel distension.

Women’s position during labour: influence on maternal and neonatal outcome

ZusammenfassungHintergrundZiel dieser Arbeit war es, den Einfluss einer aufrechten Geburtsposition im Vergleich zur Rückenlage auf mütterliche, perineale und kindliche Faktoren zu untersuchen.MethodikDiese Fall-Kontroll-Studie wurde an der Abteilung für Geburtshilfe und Gynäkologie der Universitäts-Frauenklinik Wien zwischen 1997 und 2002 durchgeführt. Insgesamt wurden 307 Frauen mit einer aufrechten Geburtsposition inkludiert, wobei als aufrechte oder auch alternative Geburtsposition die Hockgeburt definiert wurde. Die Kontrollgruppe bestand aus 307 paritätsgleichen Frauen mit spontaner vaginaler Geburt in Rückenlage. Unsere Analyse beschränkte sich auf Frauen mit einem Gestationsalter über der 37. Schwangerschaftswoche und einem normal großen Kind in Schädellage. Frauen mit medizinischen oder geburtshilflichen Risikofaktoren wurden von der Studie ausgeschlossen.ErgebnisseEs zeigte sich bei Frauen mit aufrechter Geburtsposition eine statistisch signifikante Abnahme des Schmerzmittel- und Oxytocingebrauchs (p=0,0001; p=0,001). Sowohl die Dauer der Eröffnungsphase als auch die Austreibungsphase zeigte keinen signifikanten Unterschied zwischen beiden Gruppen (p>0,05). Eine statistisch signifikant niedrigere Rate an Episiotomie wurde bei Frauen mit aufrechter Geburtsposition beobachtet (p=0,0001). Die Häufigkeit von Dammverletzungen, Vaginal- und Labialrissen unterschied sich jedoch nicht signifikant zwischen den beiden Gruppen (p>0,05). Auch bezüglich des mütterlichen Blutverlustes konnte kein Unterschied festgestellt werden (p>0,05). Weiters konnten wir keinen Unterschied bezüglich des 1- und 5-Minuten-APGAR-Wertes und des Nabelschnur-pH-Wertes entdecken (p>0,05).SchlussfolgerungDie Ergebnisse dieser Arbeit zeigen, dass die aufrechte Geburtsposition Vorteile wie eine niedrigere Episiotomierate, einen geringeren Schmerzmittel- und Oxytocingebrauch aufweist. Die beste Empfehlung wäre somit, jede Patientin mit niedrigem geburtshilflichen Risiko in der Geburtsposition entbinden zu lassen, die für sie die bequemste darstellt.SummaryAimTo assess the maternal, perineal and neonatal outcomes of an upright position compared with a supine position during vaginal delivery, in terms of defined outcome variables.MethodsThis case-control study was carried out at the Department of Obstetrics and Gynaecology of the University Hospital Vienna between 1997 and 2002. A total of 307 women who delivered in an upright position were enrolled in the study. Upright position was defined as free squatting and was also described as an alternative birth position. 307 controls, delivering in a supine position, were selected from the delivery database as the next parity-matched normal spontaneous vaginal delivery. Our analysis was restricted to a sample of women with a gestational age >37 weeks, a normal sized fetus and a pregnancy with cephalic presentation. Women with medical or obstetric risk factors were excluded.ResultsA statistically significant decrease for the use of medical analgesia (p=0.0001) and oxytocin (p=0.001) was observed in women using the upright birth position. The length of the first and second stages of labour did not significantly differ between the two groups (p>0.05). A significantly lower rate of episiotomy was detected in women who delivered in an upright position compared with women delivering supine (p=0.0001). The frequency of perineal tears, and vaginal and labial trauma did not differ between the two groups (p>0.05). When analysing maternal blood loss, no significant differences between the two groups were found (p>0.05). No differences in APGAR score <7 at 1 and 5 minutes or cord pH<7.1 were observed (p>0.05).ConclusionsThe data indicate that labouring and delivering in an upright position is associated with beneficial effects such as a lower rate of episiotomy, and a reduced use of medical analgesia and oxytocin. In our opinion, the best recommendation is to give low-risk maternity patients the option of bearing in the mode that is most comfortable for them.

Influence of the birth attendant on maternal and neonatal outcomes during normal vaginal delivery: a comparison between midwife and physician management.

SummaryBackgroundThe purpose of this study was to compare the obstetric outcome of low-risk maternity patients attended by certified midwives with that of low-risk maternity patients attended by obstetricians.Patients and methodsObstetric outcome of 1352 midwife patients was compared with that of 1352 age- and parity-matched physician patients with normal spontaneous vaginal delivery at the Department of Obstetrics and Gynecology of the University Hospital Vienna during the period from January 1997 to July 2002. Our analysis was restricted to a sample of low-risk pregnant women. Women with medical or obstetric risk factors were excluded.ResultsA significant decrease in the use of oxytocin (p=0.0001) was observed in women who selected a midwife as their primary birth attendant compared with women in the physician group. In both groups most women gave birth in a supine position; however, significantly more alternative birth positions were used by midwife patients (p=0.0001). Concerning perineal trauma, a significantly lower rate of episiotomies (p=0.0001) and perineal tears of all degrees (p=0.006) were found in midwife patients. When analyzing severe postpartum hemorrhage and postpartum infections, there were no significant differences between the two groups (p>0.05). Concerning neonatal outcome, there were no significant differences in APGAR score < 7 at 5 minutes (p>0.05).Our data clearly show the ability of certified midwives to successfully provide prenatal care and delivery to lowrisk maternity patients, with neonatal outcomes comparable to those of physician patients. The use of certified midwives supervised by obstetricians may provide the optimum model for perinatal care, particularly for those women who are low-risk maternity patients, leaving physicians free to attend to the high-risk elements of care.

Influence of labor induction on obstetric outcomes in patients with prolonged pregnancy: a comparison between elective labor induction and spontaneous onset of labor beyond term.

SummaryBACKGROUND: Prolonged pregnancy is the most frequent reason for induction of labor. This study aims to determine the effects of labor induction on delivery outcome and to quantify the risks of cesarean delivery associated with labor induction in post-date pregnancies. PATIENTS AND METHODS: This retrospective case-control study included a total of 205 women who reached 42 weeks’ gestation (41 weeks and 3 days) between January 2002 and April 2004 and who were scheduled for induction of labor with vaginal prostaglandins. These cases were matched for age and parity with controls in spontaneous labor beyond 41 weeks’ gestation. Women with any additional medical or obstetric risk factors were excluded from the study. Maternal, neonatal and delivery outcomes were the main variables of interest. RESULTS: During the study period the data of 410 women were available for analysis. Our data revealed that the use of amniotomy (p = 0.02), oxytocin (p = 0.006) and epidural analgesia (p = 0.001) was increased significantly in the induction group compared with the control group of women with spontaneous onset of labor beyond term. The frequency of cesarean delivery and vacuum extraction was also significantly higher in the induction group (p = 0.0001). The Bishop score before induction was an important factor that affected the delivery outcome, resulting in significantly higher rates of cesarean section and vacuum extraction when the score was unfavorable (p = 0.0001). A univariate regression model revealed induction per se (p = 0.0001), primiparity (p = 0.0001), increased maternal age (p = 0.006) and an unfavorable Bishop score (p = 0.0001) as statistically significant risk factors for cesarean section. In a multivariate logistic regression model, primiparity (p = 0.03), increased maternal age (p = 0.02) and an unfavorable Bishop score (p = 0.01) remained independent risk factors for cesarean section. High infant birth weight was also an independent risk factor (p = 0.03). CONCLUSIONS: Our data suggest that women undergoing labor induction because of prolonged pregnancy should be sufficiently informed regarding the risks of a cesarean section or a vacuum extraction. Furthermore, the option of elective cesarean section should be considered, particularly in primiparous women with an unfavorable cervix, higher age, and high estimated infant birth weight.ZusammenfassungHINTERGRUND: Den häufigsten Grund für eine Geburtseinleitung stellt die Terminüberschreitung dar. Ziel dieser Arbeit war es, die Auswirkungen der Geburtseinleitung bei Patientinnen mit Terminüberschreitung auf den Geburtsmodus und auf andere mütterliche und kindliche Faktoren zu untersuchen. METHODIK: Zwischen Jänner 2002 und April 2004 wurden insgesamt 205 Frauen, die aufgrund einer Terminüberschreitung (Termin + 10) mit Prostaglandinen eingeleitet wurden, in diese retrospektive Fall-Kontroll-Studie eingeschlossen. Die Kontrollgruppe bestand aus 205 alters- und paritätsgleichen Frauen, die einen spontanen Wehenbeginn nach der 41 Schwangerschaftswoche hatten. Frauen mit medizinischen oder geburtshilflichen Risikofaktoren wurden von der Studie ausgeschlossen. ERGEBNISSE: Unsere Ergebnisse zeigten in der Einleitungsgruppe eine statistisch signifikant höhere Rate an Amniotomien (p = 0,02), einen erhöhten Oxytocingebrauch (p = 0,006) und eine höhere Rate an Epiduralanalgesie (p = 0,0001). Eine statistisch signifikant höhere Sectiorate und Vakuumrate war bei den eingeleiteten Patientinnen im Vergleich zu Frauen mit spontanem Wehenbeginn und Terminüberschreitung zu verzeichnen (p = 0,0001). Der Zervixbefund (evaluiert durch den Bishop Score) vor der Einleitung hatte einen wichtigen Einfluss auf den Geburtsmodus, wobei bei einem ungünstigem Bishop Score sich eine statistisch signifikant höhere Rate an sekundären Sectiones und Vakuumextraktionen fand (p = 0,0001). In einem univariaten logistischen Regressionsmodell waren die Einleitung per se (p = 0,0001), die Primiparität (p = 0,0001), ein erhöhtes mütterliches Alter (p = 0,006) und ein ungünstiger Bishop Score (p = 0,0001) signifikante Risikofaktoren für eine Entbindung per sectionem. Im multivariaten logistischen Regressionsmodell blieben die Primiparität (p = 0,03), ein erhöhtes mütterliches Alter (p = 0,02) und ein ungünstiger Bishop Score (p = 0,01) unabhängige Risikofaktoren. Zusätzlich zeigte sich, dass ein hohes kindliches Geburtsgewicht (p = 0,03) ebenfalls einen unabhängigen Risikofaktor darstellte. SCHLUSSFOLGERUNG: Die Ergebnisse unserer Studie weisen darauf hin, dass Frauen, die aufgrund einer Terminüberschreitung eingeleitet werden, über das erhöhte Risiko einer sekundären Sectio oder einer vaginal-operativen Entbindungsart informiert werden sollten. Bei erstgebärenden Patientinnen mit unreifem Zervixbefund, einem geschätzten hohen kindlichen Geburtsgewicht sowie erhöhtem mütterlichen Alter sollte auch die Möglichkeit einer elektiven Sectio caesarea in Betracht gezogen werden.

The effect of epidural analgesia on the occurrence of obstetric lacerations and on the neonatal outcome during spontaneous vaginal delivery.

Abstractu2002The aim of this study was to determine if epidural analgesia is associated with increased risk of obstetric lacerations during spontaneous vaginal delivery. Furthermore we assessed the effect of epidural analgesia on maternal and neonatal parameters. This multicenter study consisted of an analysis of data from the delivery databases of the University Hospital of Vienna and the Semmelweis Women’s Hospital Vienna. This study was restricted to a sample that included all women with uncomplicated pregnancy, a gestational age >37th weeks and a pregnancy with cephalic presentation. Epidural analgesia was set during the first stage of labour. Techniques and management styles of epidural analgesia were the same in both hospitals. No statistically significant association was found between epidural analgesia and the occurrence of perineal tears (p=0.83), vaginal (p=0.37) or labial trauma (p=0.11). Furthermore the results demonstrated a statistically significant higher rate of primiparous women using epidural analgesia (p=0.001). A statistically significant prolonged second stage of labour was observed in women undergoing epidural analgesia (p=0.0001). Episiotomy was statistically significant more frequent in women requiring epidural analgesia (p=0.0001). Women who were treated with epidural analgesia were more likely to have labour augmented with oxytocin (p=0.001). No statistically significant differences in neonatal outcomes determined by APGAR score (p=0.84) and cord pH (p=0.23) were observed between the two groups. Women undergoing epidural analgesia demonstrated a prolonged second stage of labour, a higher rate of episiotomy and an increased use of oxytocin to augment labour. Some of these adverse effects might be caused by the higher rate of primiparous women using epidural analgesia. However, epidural analgesia showed no evidence of a detrimental effect on the integrity of the birth-canal in spontaneous vaginal delivery. In our opinion it is a save and effective method of pain relief during labour.

Influence of Hypotensive and Normotensive Anesthesia on Platelet Aggregability and Hemostatic Markers in Orthognathic Surgery

This prospective randomized study investigated the influence of normotensive and hypotensive general anesthesia on platelet aggregability, intraoperative blood loss and parameters of plasmatic coagulation during extensive orthognathic surgery. A total of 30 patients were randomly allocated for either normotensive anesthesia maintained by continuous infusion of propofol and remifentanil (NORMO, n=10) or hypotensive anesthesia, whereby hypotension was induced by increasing the infusion rate of remifentanil (HYPO-R, n=10) or by administration of nitroglycerin (HYPO-N, n=10). Whole blood platelet aggregability was significantly reduced during hypotension compared to normotensive anesthesia (P<.01, HYPO-N and HYPO-R vs. NORMO). Mean arterial blood pressure during hypotension correlated well with adenosinediphosphate- (R=.712, P<.001) and collagen-induced platelet aggregability (R=.685, P<.001). Within hypotensive study groups, postoperative fibrinogen levels were significantly different, whereas intraoperative platelet aggregability, postoperative platelet count, prothrombin time, activated partial thromboplastin time and antithrombin levels were not different. Normotensive anesthesia, however, caused significant decreases in platelet count (-29%), prothrombin time (-24%), fibrinogen (-41%) and antithrombin (-28%) and a significant prolongation in activated partial thromboplastin time (+21%) and thrombin time (+18%). There was a trend to reduced intraoperative blood loss in hypotensive study groups; however, differences were not significant. In conclusion, induced hypotension--independent of substances used for induction of hypotension--reduces intraoperative platelet aggregability, subsequently protecting the coagulation system against subclinical consumption coagulopathy. Induced hypotension-caused platelet dysfunction does not lead to an increased intraoperative blood loss, but quite on the contrary shows a trend to reduced intraoperative blood loss, possibly by preventing platelet-induced subclinical consumption coagulopathy.

The effect of epidural analgesia on obstetric lacerations and neonatal outcome during spontaneous vaginal delivery

Abstractu2002The aim of this study was to determine if epidural analgesia is associated with increased risk of obstetric lacerations during spontaneous vaginal delivery. We also assessed the effect of epidural analgesia on maternal and neonatal parameters. This multicenter study consisted of an analysis of data from the delivery databases of the University Hospital of Vienna and the Semmelweis Women’s Hospital Vienna. This study was restricted to a sample that included all women with uncomplicated pregnancy, a gestational age >37 weeks and a pregnancy with cephalic presentation. Epidural analgesia was started during the first stage of labour. Techniques and management styles of epidural analgesia were the same in both hospitals. We found thatwomen undergoing epidural analgesia had a prolonged second stage of labour, a higher rate of episiotomy and an increased use of oxytocin. Some of these adverse effects might be caused by the higher rate of primipara in the epidural group. However, epidural analgesia showed no evidence of a detrimental effect on the integrity of the birth-canal and on neonatal outcome during spontaneous vaginal delivery.

Lower flange modification improves performance of the Macintosh, but not the Miller laryngoscope blade

PurposeIn order to minimize the potential for dental damage and to improve laryngeal visualization during tracheal intubation, two commonly used laryngoscope blades were modified and compared in a clinical setting: the Miller laryngoscope blade and the Macintosh laryngoscope blade. Modified versions of both laryngoscope blades with a lowered heel (Callander modification) at the proximal end of the blade were compared to standard blades.MethodsForty patients scheduled for general anesthesia requiring endotracheal intubation were studied prospectively. Preoperatively, the patients’ airways were evaluated according to Mallampati score, thyromental distance and interincisor gap. After induction of anesthesia laryngoscopy was performed with the original laryngoscope and its modified counterpart in random order. A lateral x-ray of the neck was taken after the optimal view had been obtained, and blade-tooth distance, laryngeal view, blade-tooth contact and need for assistance were measured. Using angular calculations the laryngoscopes were analyzed at different insertion depths on graph paper, and the results were compared with data from the lateral x-rays.ResultsWith a modified Macintosh blade the blade-tooth distance was significantly greater in comparison to the original design (2.5 ± 2.1 cmvs 0.2 ± 0.1 cm,P < 0.01). Consequently the number of blade-tooth contacts was significantly lower (20%vs 75%,P < 0.05). The best laryngeal view could be obtained using a modified Macintosh laryngoscope. With a modified Miller laryngoscope laryngeal visibility was not improved and assistance was required more often to achieve adequate intubating conditions (35%vs 5%,P < 0.05).ConclusionA reduction of the proximal flange of a Miller blade decreases the blade’s effectiveness for laryngeal visualization, whereas a similar modification of a Macintosh blade increases blade-tooth distance, decreases the number of blade tooth contacts and provides a better laryngeal view.RésuméObjectifPour réduire le risque de dommage aux dents et pour améliorer la visualisation du larynx pendant ľintubation endotrachéale, deux lames de laryngoscope fréquemment utilisées ont été modifiées et comparées en situation clinique, celles des laryngoscopes Miller et Macintosh. Les versions modifiées des deux lames, munies ďun talon plus bas à ľextrémité proximale (modification Callander), ont été comparées aux lames régulières.MéthodeQuarante patients devant subir une anesthésie générale avec intubation endotrachéale ont fait ľobjet ďune étude prospective. Ľévaluation préopératoire des voies respiratoires selon le score de Mallampati a révélé la distance thyromentonnière et ľespace interincisive. Après ľinduction de ľanesthésie, la laryngoscopie a été réalisée avec le laryngoscope original et sa version modifiée suivant un ordre aléatoire. Une fois la vision optimale obtenue, une radiographie latérale du cou a été prise, puis la distance entre la lame et les dents, la vision laryngée, la présence de contact entre la lame et les dents et la nécessité ďune assistance ont été évaluées. D’après le calcul des angles, une analyse graphique des laryngoscopes a été faite pour différentes profondeurs ďinsertion et les résultats comparés avec les données de la radiographie latérale.RésultatsAvec la lame Macintosh modifiée, la distance dentlame a été significativement plus grande qu’avec la lame originale (2,5 ± 2,1 cm vs 0,2 ± 0,1 cm, P < 0,01). Le nombre de contacts dent-lame a donc été significativement plus bas (20 % vs 75 %, P < 0,05). La meilleure vision laryngée a pu être obtenue avec une lame Macintosh modifiée. Avec le laryngoscope Miller modifié, la visibilité du larynx n’était pas améliorée et une assistance a été plus souvent requise pour atteindre des conditions ďintubation adéquates (35 % vs 5 %, P < 0,05).ConclusionUne réduction du manche proximal de la lame Miller diminue la qualité de la visualisation laryngée obtenue tandis qu’une modification similaire de la lame Macintosh améliore la distance dent-lame, diminue le nombre de contacts dent-lame et fournit une meilleure vision du larynx.