Prerequisites of a functional haemostasis

Abstract

A coagulopathy is an independent predictor of perioperative mortality. Therefore, maintenance of a functional coagulation system is an essential precondition to reduce morbidity and mortality in the perioperative setting. Sound coagulability also depends on prerequisites such as body temperature, acid-base balance, plasma calcium concentration and haematocrit. Severe trauma or perioperative bleeding can gravely influence these factors and boost the blood loss. Common global tests of coagulation are not helpful in this setting because they are conducted on plasma with a normalised temperature of 37 degrees C, an excess of calcium and a stabile acid-base balance. Hence, knowledge of the effects of altered prerequisites is a premise to avoid a possibly lethal coagulopathy. According to the current literature, an increased risk for clinically significant coagulopathy exists with a body temperature <or=34 degrees C, an acidosis <or=7.15, ionised calcium under 0.9 mmol/l or a haematocrit under 30-35%. A combination of these factors deteriorates the coagulopathy and hypothermia in addition to acidosis is especially harmful. Prevention of derangement of these factors should start as early as possible, i.e. in trauma patients at the scene of the accident and should be continued in the operating room.

Perioperative Coagulation Management and Control of Platelet Transfusion by Point-of-Care Platelet Function Analysis

“…The platelets are damaged mechanically by the pump and are activated by contact with the artificial surface of the cardiopulmonary bypass circuit. Hypothermia also induces platelet function disorders [24,122,131,132]. In addition, heparin can cause an unspecific activation and therefore a consumption of platelets [133].…”

“…5, 6), -prophylactic or therapeutic application of antifibrinolytics ( fig. 7), -ROTEM analysis after declamping of the aorta in order to predict the risk of bleeding even after protamine administration, -optimizing the basic conditions for haemostasis (body temperature, pH, haemoglobin level, ionised calcium concentration) before weaning from cardiopulmonary bypass [122,131], -optimizing of heparin reversal with protamine under consideration of ACT and ROTEM analysis [118,119], -ROTEM-and Multiplate-based coagulation management in case of diffuse bleeding even after protamine administration ( fig. 8), Cut-off values for therapeutic interventions recommended in this algorithm corresponds with the clinical experience of the participating clinics and are furthermore based on the results of the Multiplate study carried out by Rahe-Meyer et al [96] in Hannover.…”

Parenteral

“…If the reconstituted products are stored in the fridge or in the freezer, they should be brought to room temperature prior to administration. Otherwise infusion can disturb the blood-and body temperature of the patients [47]. Further disadvantages of storing in the freezer are:…”

Coagulation management in the treatment of multiple trauma

“…Unterhalb von 35°C kommt es durch ein verstärktes "pooling" in Milz und Leber zusätzlich zu einer Ver minderung zirkulierender Thrombozyten [52]. Zwar reagieren die einzelnen Gerin nungsfaktoren unterschiedlich sensibel, aber unterhalb von 33°C wird ihre Aktivi tät in der Größenordnung von 10% pro°C Temperaturabnahme reduziert [53,54,67]. Die Hypothermie beeinflusst dabei in ers ter Linie die Geschwindigkeit der initialen Thrombinbildung, weniger seine Festig keit (Schweinemodell; [65]).…”

“…ein BE≤−12 mmol/l entspricht an nähernd einer Halbierung der Faktoren aktivität. Auch die Thrombozyten wer den sowohl quantitativ als auch qualita tiv erheblich beeinträchtigt [53,54].…”