Thomas Hamp

The effect of a bolus dose of intravenous lidocaine on the minimum alveolar concentration of sevoflurane: a prospective, randomized, double-blinded, placebo-controlled trial.

BACKGROUND: The anesthetic effect of volatile anesthetics can be quantified by the minimum alveolar concentration (MAC) of the drug that prevents movement in response to a noxious stimulus in 50% of patients. The underlying mechanism regarding how immobilization is achieved by volatile anesthetics is not thoroughly understood, but several drugs affect MAC. In this study, we investigated the effect of a single IV bolus dose of lidocaine on the MAC of sevoflurane in humans. METHODS: We determined the MAC for sevoflurane using the Dixon “up-and-down” method in 3 groups of patients, aged 30 to 65 years, who underwent elective surgery (30 patients per group). Study medication (placebo, 0.75 mg·kg−1 lidocaine or 1.5 mg·kg−1 lidocaine) was administered 3 minutes before skin incision after a 15-minute equilibration period and the response to skin incision was recorded (movement versus no movement). RESULTS: MAC was 1.86% ± 0.40% in the placebo and 1.87% ± 0.45% in the 0.75 mg·kg−1 lidocaine group (P = 1.00). MAC was 1.63% ± 0.24% in the 1.5 mg·kg−1 lidocaine group, which was significantly lower than that of the placebo group (mean difference of 0.23% sevoflurane [95% adjusted confidence interval {CI}, 0.03–0.43]; P = 0.022). No significant difference was observed between the 0.75 mg·kg−1 lidocaine and the placebo groups (mean difference of −0.01% sevoflurane [95% adjusted CI, −0.27 to 0.25]; P = 1). CONCLUSIONS: IV 1.5 mg·kg−1 lidocaine decreased the MAC by at least 0.03% sevoflurane (mean difference 0.23% sevoflurane [95% adjusted CI, 0.03–0.43]). We did not observe a significant reduction in the MAC of sevoflurane with the IV administration of 0.75 mg·kg−1 lidocaine.

Intravenous lidocaine increases the depth of anaesthesia of propofol for skin incision--a randomised controlled trial.

The anaesthetic potency of intravenous propofol is quantified by its Cp50 value, which is defined as the plasma concentration required to prevent movement response in 50% of patients to surgical stimuli. We hypothesised that, in addition to propofol anaesthesia, an intravenous bolus of lidocaine 1.5 mg/kg will decrease the Cp50 value of propofol during anaesthesia.

Increased plasma vaspin concentration in patients with sepsis: an exploratory examination

Introduction Vaspin (visceral adipose tissue-derived serpin) was first described as an insulin-sensitizing adipose tissue hormone. Recently its anti-inflammatory function has been demonstrated. Since no appropriate data is available yet, we sought to investigate the plasma concentrations of vaspin in sepsis. Materials and methods 57 patients in intensive care, fulfilling the ACCP/SCCM criteria for sepsis, were prospectively included in our exploratory study. The control group consisted of 48 critically ill patients, receiving intensive care after trauma or major surgery. Patients were matched by age, sex, weight and existence of diabetes before statistical analysis. Blood samples were collected on the day of diagnosis. Vaspin plasma concentrations were measured using a commercially available enzyme-linked immunosorbent assay. Results Vaspin concentrations were significantly higher in septic patients compared to the control group (0.3 (0.1-0.4) ng/mL vs. 0.1 (0.0-0.3) ng/mL, respectively; P < 0.001). Vaspin concentration showed weak positive correlation with concentration of C-reactive protein (CRP) (r = 0.31, P = 0.002) as well as with SAPS II (r = 0.34, P = 0.002) and maximum of SOFA (r = 0.39, P < 0.001) scoring systems, as tested for the overall study population. Conclusion In the sepsis group, vaspin plasma concentration was about three-fold as high as in the median surgical control group. We demonstrated a weak positive correlation between vaspin and CRP concentration, as well as with two scoring systems commonly used in intensive care settings. Although there seems to be some connection between vaspin and inflammation, its role in human sepsis needs to be evaluated further.

Gender and age-specific aspects of awareness and knowledge in basic life support

Background The ‘chain of survival’—including early call for help, early cardiopulmonary resuscitation (CPR) and early defibrillation—represents the most beneficial approach for favourable patient outcome after out-of-hospital cardiac arrest (OHCA). Despite increasing numbers of publicly accessible automated external defibrillators (AED) and interventions to increase public awareness for basic life support (BLS), the number of their use in real-life emergency situations remains low. Methods In this prospective population-based cross-sectional study, a total of 501 registered inhabitants of Vienna (Austria) were randomly approached via telephone calls between 08/2014 and 09/2014 and invited to answer a standardized questionnaire in order to identify public knowledge and awareness of BLS and AED-use. Results We found that more than 52 percent of participants would presume OHCA correctly and would properly initiate BLS attempts. Of alarming importance, only 33 percent reported that they would be willing to perform CPR and 50 percent would use an AED device. There was a significantly lower willingness to initiate BLS attempts (male: 40% vs. female: 25%; OR: 2.03 [95%CI: 1.39–2.98]; p<0.001) and to use an AED device (male: 58% vs. female: 44%; OR: 1.76 [95%CI: 1.26–2.53]; p = 0.002) in questioned female individuals compared to their male counterparts. Interestingly, we observed a strongly decreasing level of knowledge and willingness for BLS attempts (-14%; OR: 0.72 [95%CI: 0.57–0.92]; p = 0.027) and AED-use (-19%; OR: 0.68 [95%CI: 0.54–0.85]; p = 0.001) with increasing age. Conclusion We found an overall poor knowledge and awareness concerning BLS and the use of AEDs among the Viennese population. Both female and elderly participants reported the lowest willingness to perform BLS and use an AED in case of OHCA. Specially tailored programs to increase awareness and willingness among both the female and elderly community need to be considered for future educational interventions.

The impact of cardiopulmonary resuscitation (CPR) manikin chest stiffness on motivation and CPR performance measures in children undergoing CPR training—A prospective, randomized, single-blind, controlled trial

Background Cardio-pulmonary-resuscitation (CPR) training starting at the age of 12 years is recommended internationally. Training younger children is not recommended because young children lack the physical ability to perform adequate CPR and discouragement to perform CPR later is apprehended. The aim of this study was to answer the following questions: Are younger children discouraged after CPR training? Is discouragement caused by their lack in physical ability to perform adequate chest compressions on a standard manikin and would the use of manikins with a reduced resistance affect their motivation or performance? Methods We investigated the motivation and CPR performance of children aged 8–13 years after CPR training on manikins of different chest stiffness in a prospective, randomized, single-blind, controlled trial. 322 children underwent randomization and received 30 minutes CPR training in small groups at school. We used two optically identical resuscitation manikins with different compression resistances of 45kg and 30kg. Motivation was assessed with a self-administered questionnaire. Performance was measured with the Resusci®Anne SkillReporter™. Findings Motivation after the training was generally high and there was no difference between the two groups in any of the questionnaire items on motivation: Children had fun (98 vs. 99%; P = 0.32), were interested in the training (99 vs. 98%; P = 0.65), and were glad to train resuscitation again in the future (89 vs. 91%; P = 0.89). CPR performance was generally poor (median compression score (8, IQR 1–45 and 29, IQR 11–54; P<0.001) and the mean compression depth was lower in the 45kg-resistance than in the 30kg-resistance group (33±10mm vs. 41±9; P<0.001). Conclusions Compression resistances of manikins, though influencing CPR performance, did not discourage 8 to 13 year old children after CPR training. The findings refute the view that young children are discouraged when receiving CPR training even though they are physically not able to perform adequate CPR.

Effect of intravenous S-ketamine on the MAC of sevoflurane: a randomised, placebo-controlled, double-blinded clinical trial

Background: Ketamine is routinely used in operating theatres, emergency departments, ICUs, and even outpatient units. Despite the widespread use of ketamine, only basic aspects of its interactions with inhalation anaesthetic agents are known, and formal testing of interactions in humans is lacking. The minimum alveolar concentration (MAC) of inhalation anaesthetics is used to guide the depth of anaesthesia, and several drugs are known to influence the MAC. The aim of this study was to investigate whether intravenous application of ketamine influences the MAC of sevoflurane in humans. Methods: Adult patients undergoing elective surgery were included in this randomised, double‐blinded, placebo‐controlled study. Patients were assigned to one of three groups, each of which received a bolus of placebo, 0.5 mg kg−1 S‐ketamine, or 1 mg kg−1 S‐ketamine followed by an infusion of the same amount per hour after inhalation induction with sevoflurane was performed. The response to skin incision (movement vs non‐movement) was recorded. The MAC of sevoflurane was assessed using an up‐and‐down titration method. Results: Sixty patients aged 30–65 yr were included. Each group consisted of 20 patients. The MAC of sevoflurane was higher in the placebo group (2.1 (sd 0.1) %) than in the low‐dose ketamine group (0.9 (0.1)%, P<0.01) and the high‐dose ketamine group (0.5 (0.1)%, P<0.01). In addition, the MAC of sevoflurane was higher in the low‐dose ketamine group compared with the high‐dose ketamine group (P<0.01). Conclusions: The administration of S‐ketamine significantly and dose‐dependently reduced the MAC of sevoflurane in humans. Clinical trial number: EudraCT ref. no. 2012‐001908‐38.