[Update on point-of-care-based coagulation treatment : Systems, reagents, device-specific treatment algorithms]

Viscoelastic test (VET) procedures suitable for point-of-care (POC) testing are in widespread clinical use. Due to the expanded range of available devices and in particular due to the development of new test approaches and methods, the authors believe that an update of the current treatment algorithms is necessary. The aim of this article is to provide an overview of the currently available VET devices and the associated reagents. In addition, two treatment algorithms for the VET devices most commonly used in German-speaking countries are presented.

[Basic algorithm for Point-of-Care based hemotherapy: perioperative treatment of coagulopathic patients]

During perioperative treatment of coagulopathic patients the so-called Point-of-Care (POC) analyses enable more rapidly available and more comprehensive hemostatic analyses compared to routinely performed conventional coagulation testing, such as activated partial thromboplastin time (aPTT), international normalized ratio (INR), fibrinogen concentration and platelet count. In this review article a hemotherapy algorithm is presented which is based on viscoelastic and aggregometric POC measurements. The algorithm was designed double sided and consists of a general and a special part. The general part contains boxes and fields for sociodemographic data and gives general recommendations for coagulation management and therapy specifications for particular patient collectives and presents proposals for emergency reversal of anticoagulation therapy. The special part refers to basic physiological conditions for hemostasis and asks for measurement results of clot initiation, clot firmness, clot stability and platelet function analyses. Reference values were defined for each parameter and therapeutic options are presented. In cases of persistent coagulopathy despite algorithm-conform therapy, the algorithm could be run through once again. Finally, the algorithm presents therapeutic options for an ultima ratio therapy approach.

[Less pain on injection by a new formulation of propofol? A comparison with propofol LCT]

BACKGROUND

Pain on injection is a major disadvantage of propofol, experienced by the vast majority of patients. Since the traditional formulation has almost normal osmolality and pH, it is hypothesised that the concentration of free propofol in the aqueous phase of the emulsion is responsible for the pain and that reducing the amount of free propofol would also reduce the frequency and intensity of pain on injection. This study was designed to investigate whether pain on injection can be reduced in frequency and intensity by a new formulation of propofol.

METHODS

We performed a monocentre, controlled, randomised, double-blind study to compare the pain produced by intravenous injection of a new propofol preparation (propofol-MCT/LCT) with standard propofol in patients undergoing elective surgical procedures. A total of 184 non-premedicated patients received either 1% propofol prepared in a mixture of medium and long chain triglycerides (Propofol-MCT/LCT, Propofol- Lipuro, B. Braum Melsungen AG) or standard 1% propofol prepared exclusively in long chain triglycerides (Propofol-LCT; Disoprivan, AstraZeneca) into a vein of the dorsal hand for induction of anaesthesia. Anaesthesia was maintained by TIVA with propofol and remifentanil. Pain on injection was recorded and graded as none, mild, moderate or severe.

RESULTS

Patients receiving propofol-MCT/LCT had a significantly lower incidence of pain on injection compared to the standard propofol group (37% vs 64%) with the intensity of pain also being less severe. There were no differences between both groups in propofol dosage for induction (3.2 +/- 0.8 mg/kg vs 3.3 +/- 0.9 mg/kg) and maintenance of anaesthesia (3.4 +/- 0.6 mg/kg/h vs 3.2 +/- 0.5 mg/kg/h), remifentanil dosage (25 +/- 6 micrograms/kg/h vs. 24 +/- 6 micrograms/kg/h), intraoperative hemodynamics, recovery parameters and postoperative patient satisfaction. Postoperative thrombophlebitis at the injection site for propofol was not observed in any of the patients.

CONCLUSIONS

Propofol-MCT/LCT produced significantly less pain on injection when compared to standard propofol in ASA I and II patients undergoing elective surgery. Pain was also significantly less severe, with both effects presumably being due to the lower concentration of free propofol in the MCT/LCT-preparation. With regard to injection pain propofol-MCT/LCT offers significant a advantage over standard propofol.

[Remifentanil with propofol or isoflurane. A comparison of the recovery times after arthroscopic surgery]

OBJECTIVES

Due to its unique pharmacokinetics, the new esterase-metabolised opioid remifentanil results in rapid post-anesthesia recovery. The aim of this clinical investigation was to compare recovery times after remifentanil anaesthesia in combination with hypnotic concentrations of either propofol or isoflurane. Dosages used in the study protocol were based on recommendations by the pharmaceutical manufacturer.

METHODS

Patients (ASA status I-II) scheduled for elective arthroscopy were included in this trial. Without premedication in the morning, anaesthesia was induced identically in both groups: remifentanil bolus (1 microgram/kg), start of remifentanil-infusion (0.5 micrograms/kg/min), followed immediately by propofol (ca. 2 mg/kg). For maintenance of anaesthesia remifentanil (0.25 micrograms/kg/min) was combined with either a propofol infusion of 0.1 mg/kg/min or 0.5 MAC isoflurane (= 0.6 vol. %) in O2/air. Anaesthetic delivery was discontinued simultaneously with termination of surgery and recovery times were recorded.

RESULTS

A total of 40 patients were studied at random in two groups of 20 each with comparable demographic data and anaesthetic technique (Tables 1 and 2). In both groups emergence was very rapid. Recovery times were significantly shorter for remifentanil-isoflurane than for remifentanil-propofol (Table 3): spontaneous ventilation 5.1 vs 8.1 min (P < 0.05), extubation 5.5 vs 8.6 min (P < 0.02), post-anaesthesia recovery score > or = 9 of 10 points 6.2 vs 11.3 min (P < 0.01), and arrival at PACU 16.2 vs 19.2 min (P < 0.01). Mild to moderate shivering was noted in 40% of all patients (9 cases following isoflurane, 7 following propofol).

CONCLUSIONS

Using the manufacturer's recommended dosages, emergence after remifentanil anaesthesia is more rapid with 0.5 MAC isoflurane than with 0.1 mg/kg/min propofol. These results are most probably due to the different pharmacological properties of both co-anaesthetics, especially the applied dosages, and to different interactions with remifentanil. Present clinical experience suggests that a further dose reduction, especially for propofol, is possible. For both remifentanil groups emergence was remarkably rapid between return of consciousness and the awake state (on-off phenomenon), which might contribute to post-anaesthesia safety.