SummaryClassically haemodilution is regarded as causing coagulopathy. However, haemodilution with saline seems to cause a hypercoagulable state both in vivo and in vitro. The aim of the present study was to measure the effect of mild to severe haemodilution using thrombelastography. Blood samples were taken in 12 healthy volunteers and divided into seven aliquots. One aliquot was undiluted and acted as control. The other six were diluted with normal saline, Ringer Acetate, 4% albumin, Dextran 70, 6% and 10% hydroxyethylstarch to 10%, 20%, 40%, 50% and 60% dilution. The dilution was checked by measuring the haemoglobin concentration. Each aliquot was placed in a temperature-controlled thrombelastography channel. Increased coagulation activity, as measured by thrombelastography changes, was detected at low and medium levels of dilution with all the tested solutions. At more than 40% dilution, coagulation returned to normal while in the case of dextran and hydroxyethylstarch coagulopathy developed. For crystalloids and albumin, dilution had to exceed 50% before coagulation was impaired. If these findings can be reproduced in vivo, they may have implications for transfusion practice and prophylaxis against thrombosis.Keywords Coagulation: haemodilution; thrombelastography. Correspondence to: Dr K. Ekseth E-mail: kare.ekseth@rikshospitalet.no Accepted: 14 May 2002 Haemodilution is common following blood loss. Traditionally the focus during haemodilution has been on the oxygen carrying capacity of blood [1], and haemodilution has generally been regarded as a cause of hypocoagulation. However, in 1950 Tocantins et al. reported that moderate blood dilution with normal saline caused accelerated coagulation. Numerous reports describing alterations of coagulation during haemodilution followed [2][3][4][5][6]. During normovolaemic haemodilution in patients under anaesthesia, abnormal haemostasis develops before impaired global tissue oxygenation [7].Thrombelastography was developed as a research tool [8] but has been developed into a clinically useful coagulation monitor [9]. Thrombelastography can be used at the bedside and can detect impaired coagulation as well as hypercoagulable states. By using thrombelastography, Tuman et al. found increased coagulability with progressive blood loss, even when losses were replaced by crystalloids and packed red cells [3].Therefore the aim of the present investigation was to use thrombelastography in vitro to find the level of dilution required to cause hypercoagulation with commonly used crystalloids and colloids. We also wanted to determine whether the degree of dilution influenced coagulation. MethodsThe thrombelastograph (Haemoscope Corp., 5693 West Howard Street ⁄ Niles, IL 60714, USA) consists of a heated (37°C) cuvette containing 0.36 ml of whole blood. A pin suspended by a torsion wire is lowered into the blood. The cuvette oscillates on its vertical axis through 4.0-4.5 degrees. While the blood remains liquid, Anaesthesia, 2002Anaesthesia, , 57, pages 1102Anaesthesia, -1...

This series of 1449 consecutive outpatient microsurgical spine decompressions adds to the growing literature in favor of outpatient spinal surgery in properly selected patients. In our study, 99.8% of the patients were successfully discharged either to their homes or to a hotel on the day of surgery. The overall complication rate was 3.5%, surgical mortality was 0%, and only 1.5% had to be admitted to a hospital within 3 months after surgery.

ACDF in carefully selected patients with CDD appears to be safe in the outpatient setting, provided a sufficient postoperative observation period. The clinical outcome and patient satisfaction of outpatients are comparable to that of inpatients.

Intracranial sinus thrombosis, even in the worst neurological state, should be treated aggressively. A cornerstone in treatment is systemic anticoagulant therapy and repeated neuroradiological studies. When, despite adequate anticoagulant therapy and intensive care, neurological deterioration occurs, a combination of open thrombectomy and local thrombolytic therapy should be considered.

We present a rare case with postspinal headache resulting in an intracranial subdural haematoma. After 5 days of persistant headache the condition was recognized and diagnosed on a computerized tomography-scan (CT) of the skull. The patient was operated with evacuation of the haematoma 2 weeks after the spinal anaesthesia and recovered completely.