Gabriele Noeldge-Schomburg

Comparison of invasive and less-invasive techniques of cardiac output measurement under different haemodynamic conditions in a pig model.

Background and objective: Despite the introduction of various less‐invasive concepts of cardiac output measurement, pulmonary arterial thermodilution is still the most common measurement technique. Methods: This prospective controlled study was designed to compare different methods of cardiac output measurement simultaneously. Pulmonary arterial thermodilution, transpulmonary thermodilution (PiCCO™), trans‐oesophageal echo‐Doppler probe (HemoSonic™) and partial carbon dioxide rebreathing technique (NICO™ monitor) were evaluated against a peri‐aortic transit‐time flow‐probe as reference method in a clinically relevant animal model. After approval from the Local Ethics Committee on Animal Research, the investigations were conducted in nine anesthetized domestic pigs. Systemic haemodynamics were modulated systematically by the application of catecholamines, caval occlusion and exsanguination. Statistical analysis was performed with Bland‐Altman and linear regression. Results: A total of 366 paired cardiac output measurements were carried out at a reference cardiac output between 0.5 and 7 L min−1. The correlation coefficients for pulmonary arterial and transpulmonary thermodilution against reference were 0.93 and 0.95, for trans‐oesophageal Doppler and partial rebreathing technique 0.84 and 0.77. Pulmonary arterial thermodilution and transpulmonary thermodilution showed comparable bias and limits of agreement. Where HemoSonic™ showed an overestimation of cardiac output at a higher precision, NICO™ overestimated low and underestimated higher cardiac output values. Conclusions: Our data suggest that pulmonary arterial thermodilution and PiCCO™ may be interchangeably used for cardiac output measurement even under acute haemodynamic changes. The method described by Bland and Altman demonstrated an overestimation of cardiac output for both thermodilution methods. HemoSonic™ and NICO™ offer non‐invasive alternatives and complementary monitoring tools in numerous clinical situations. Trend monitoring and haemodynamic optimizing can be applied sufficiently, when absolute measures are judged critically in a clinical context. The use of the NICO™ system seems to be limited during acute circulatory changes.

Does the timing of tracheal intubation based on neuromuscular monitoring decrease laryngeal injury? A randomized, prospective, controlled trial

Vocal cord injuries (VCI) and postoperative hoarseness (PH) are common complications after general anesthesia. Poor muscle relaxation at the moment of tracheal intubation may result in VCI. There is a large interindividual variation in neuromuscular depression after administration of neuromuscular blocking drugs. Therefore, the optimal individual timing of tracheal intubation based on neuromuscular monitoring (monitoring) may decrease VCI. In this prospective trial, 60 patients were randomized into 2 groups: Monitoring group: tracheal intubation at maximum block based on monitoring after atracurium 0.5 mg/kg and 2-min group: tracheal intubation 2 min after injection of atracurium 0.5 mg/kg. Intubating conditions were evaluated with the Copenhagen score. VCI were examined by stroboscopy before and 24 and 72 h after surgery. PH was assessed at 24, 48, and 72 h after surgery by a standardized interview. Excellent intubating conditions were significantly increased in the monitoring group compared with the 2-min group: 8 versus 2 patients, respectively (P = 0.036). The incidence of PH between the study groups was comparable: 7 (monitoring) versus 8 patients (2-min) (P = 0.860). Similar findings were observed for VCI: 9 versus 5 patients; respectively (P = 0.268); type of VCI: thickening of the vocal cords: 8 (monitoring) versus 5 (2-min) patients (P = 0.423), hematomas: 2 patients in each group (not significant). The present study demonstrated that neuromuscular monitoring improved endotracheal intubating conditions. However, tracheal intubation at maximum intensity of neuromuscular block was not associated with a decrease in vocal cord injuries.

The influence of residual neuromuscular block on the incidence of critical respiratory events. A randomised, prospective, placebo-controlled trial.

Context Residual paralysis is associated with post-operative pulmonary complications, including critical respiratory events. Objective We determined the incidence of critical respiratory events, such as hypoxaemia, in patients with minimal residual neuromuscular blockade and compared these data with those from patients with full recovery of blockade. Design Randomised, prospective, placebo-controlled trial. Setting Single centre; Rostock, Germany, from January 2007 to February 2008. Patients One hundred and thirty-two adult patients, aged 18–80 years, with the American Society of Anesthesiology I–III physical status, undergoing orthopaedic surgery under general anaesthesia, including rocuronium to produce neuromuscular blockade; 114 patients were randomised to one of two groups: neostigmine group (neostigmine 20 &mgr;g kg−1) or placebo group (saline). Interventions In the patients in the neostigmine group, the tracheal tube was removed at a train-of-four (TOF) ratio of 1.0; in the patients in the placebo group, the trachea was extubated at a TOF ratio less than 1.0, but without fade in TOF and double-burst stimulation (DBS). Neuromuscular monitoring was assessed simultaneously with qualitative TOF/DBS monitoring, and with quantitative calibrated acceleromyography. Critical respiratory events, such as hypoxaemia, were assessed in the post-anaesthesia care unit. Main outcome measures Forty-five patients (39.5%) became hypoxaemic (SaO2 < 93%); there was a significant difference between the groups (29 patients in the placebo group versus 16 in the neostigmine group; P = 0.021). Results In the neostigmine group, all patients were extubated at a TOF ratio of 1.0. In the placebo group, the median TOF ratio was 0.7 (range: 0.46–0.9; P < 0.001). The median time for spontaneous recovery in the placebo group was 16 min (range 3–49 min). Neostigmine 20 &mgr;g kg−1 was effective in antagonising rocuronium-induced blockade without fade in TOF and DBS. Conclusion In this randomised, prospective, placebo-controlled trial, minimal residual block was associated with hypoxaemia in the post-anaesthesia care unit. Neostigmine 20 &mgr;g kg−1 was effective in antagonising rocuronium-induced (minimal) blockade.

Rocuronium is not associated with more vocal cord injuries than succinylcholine after rapid-sequence induction: a randomized, prospective, controlled trial.

Postoperative hoarseness (PH), sore throat (ST), and vocal cord injuries (VCI) are common complications after general anesthesia. Excellent endotracheal intubating conditions are associated with less laryngeal morbidity than good or poor intubating conditions. Thus, we tested the hypothesis that a rapid-sequence induction (RSI) with succinylcholine would lead to less PH and VCI than with rocuronium. In this prospective trial, 160 patients were randomized in 2 groups to receive thiopental 5.0 mg/kg, fentanyl 3.0 &mgr;g/kg, succinylcholine 1.0 mg/kg, or rocuronium 0.6 mg/kg during RSI. PH and ST were assessed at 24, 48, and 72 h after surgery, VCI were examined by stroboscopy in those patients who had PH >3 days. Excellent and clinically acceptable intubating conditions were significantly increased in the succinylcholine group compared with the rocuronium group: 57% versus 21% and 89% versus 59%, respectively (P < 0.001). The incidence and severity of PH, and VCI between the succinylcholine and the rocuronium groups did not differ significantly: PH: 50% versus 51% (P = 0.99) and VCI: 3% versus 1% (P = 0.98), respectively. Similar findings were found for ST, 39% versus 28% (P = 0.22), and postoperative myalgia, 39% versus 29% (P = 0.25), respectively. Intubating conditions were significantly better in the succinylcholine group compared with the rocuronium group. The incidence and severity of ST and myalgia were not increased in the patients receiving succinylcholine. However, the rate of PH and VCI was similar to the rocuronium group.

Clinical evaluation of a simultaneous closed-loop anaesthesia control system for depth of anaesthesia and neuromuscular blockade*.

We developed a closed‐loop system to control the depth of anaesthesia and neuromuscular blockade using the bispectral index and the electromyogram simultaneously and evaluated the clinical performance of this combined system for general anaesthesia. Twenty‐two adult patients were included in this study. Anaesthesia was induced by a continuous infusion of remifentanil at 0.4 μg.kg−1.min−1 (induction dose) and then 0.25 μg.kg−1.min−1 (maintenance dose) and propofol at 2 mg.kg−1 3 min later. The combined automatic control was started 2 min after tracheal intubation. The depth of anaesthesia was recorded using bispectral index monitoring using a target value of 40. The target value of neuromuscular blockade, using mivacurium, was a T1/T10 twitch height of 10%. The precision of the system was calculated using internationally defined performance parameters. Twenty patients were included in the data analysis. The mean (SD) duration of simultaneous control was 129 (69) min. No human intervention was necessary during the computer‐controlled administration of propofol and mivacurium. All patients assessed the quality of anaesthesia as ‘good’ to ‘very good’; there were no episodes of awareness. The mean (SD) median performance error, median absolute performance error and wobble for the control of depth of anaesthesia and for neuromuscular blockade were −0.31 (1.78), 6.76 (3.45), 6.32 (2.93) and −0.38 (1.68), 3.75 (4.83), 3.63 (4.69), respectively. The simultaneous closed‐loop system using propofol and mivacurium was able to maintain the target values with a high level of precision in a clinical setting.

Thoratec left ventricular assist device for bridging to recovery in fulminant acute myocarditis.

Fulminant acute myocarditis can be the cause of rapid cardiac decompensation that is resistant to maximal medical therapy. Successful weaning from left ventricular mechanical support is very rare in fulminant myocarditis. We report the case of a young patient with viral myocarditis who was successfully weaned from a Thoratec left ventricular assist device with full recovery of myocardial function.

Sevoflurane at 1.0 MAC together with remifentanil and propofol produces clinically acceptable intubation conditions at the vocal cords: A prospective randomized study:

Objective The overall intubation conditions after tracheal intubation with remifentanil, propofol, and sevoflurane at 1.0 minimum alveolar concentration (MAC) are worse than with rocuronium at 0.45 mg/kg. Therefore, we compared the intubation conditions and laryngeal morbidity (vocal cord injuries, hoarseness, and sore throat) with sevoflurane at 1.2 and 1.4 MAC versus 1.0 MAC. Methods In this prospective clinical trial, 90 patients were randomized to 3 groups: the sevoflurane 1.0, 1.2, and 1.4 MAC groups. At 3 min, tracheal intubation was performed and the patients’ intubation conditions were assessed. The vocal cords were examined for injury by videolaryngoscopy. Additionally, the incidence and severity of laryngeal morbidity were compared between women and men. Results Acceptable intubation conditions were seen in 72% of the patients without significant differences between the groups. Overall, vocal cord injuries (oedema) occurred in three (4%) patients. Women reported sore throat more often than men (51% vs. 21%, respectively). Conclusions Intubation conditions were not improved with higher sevoflurane concentrations. The incidence and severity of sore throat were greater in women than men. Trial registration: ClinicalTrials.Gov: NCT 01896245

Gender differences in the intubating conditions of rocuronium: A-451

Department of Anaesthesia and Intensive Care, University of Rostock, Rostock, Germany Background and Goals: There is increasing evidence for sex differences in the pharmacodynamics (PD) of anaesthetic drugs and neuromuscular blocking agents (NMBA), e.g. rocuronium (Roc; 1). The sensitivity of women to Roc was higher compared with men, requiring 30% less of the drug to achieve the same degree of neuromuscular block (2) and onset times were shorter. However, whether gender influences the intubating con-ditions (IntCond) after Roc and leads to an improvement of the IntCond in female patients (Pat) is unclear. Materials and Methods: After Ethics Committee approval and informed consent, 60 female and 60 male Pat were randomised each in 2 groups (Gr) to receive Roc 0.6 mg/kg or succinylcholine (Sux; Control-Gr) 1.0 mg/kg. Induction: thiopentone (5 mg/kg), fentanyl (3mg/kg), Roc (Roc-Gr) or Sux (SuxGr). 60s later, endotracheal intuba-tion(Int) was performed. Time of Int, difficulty of intubation (Cormack), and IntCond (3) were assessed. Stat: x2 test. Results and Discussion: Men were significantly larger and heavier (p 0.001) than women, but the body mass index was comparable (n.s.). Int time, and Cormack grades were comparable (n.s.). However, clinically acceptable (Clin accept; excellent and good) IntCond after Roc were significantly increased in the Female Gr compared to the Male Roc Gr: 80% vs. 47%, respectively; p 0.05.