Dangers of using a pneumatic pressure bag to increase transfusion rate

I was interested to read the letter by Kinnear and Stase (Anaesthesia 1998; 53: 408) relating a case of extravasation of fluid from a pressurised peripheral line in a patient following cardiopulmonary bypass (CPB). The leak occurred through an upstream hole in the vein due to a previous attempt at siting the cannula in the same arm. I have had a similar, though potentially more serious, experience. A large-bore cannula was sited in a vein in the patient's left forearm together with a radial artery cannula prior to commencement of anaesthesia for CPB. Anaesthesia progressed uneventfully until after separation from CPB, when, whilst the patient was hypovolaemic, a rapid transfusion of fluid was commenced via the peripheral line with the aid of a pneumatic pressure bag device. Following transfusion of 500 ml of gelofusine and a unit of autologous blood, the patient's arterial pressure, as measured via the radial artery cannula, started to fall rapidly, the central venous pressure remaining low. Palpation of the aorta suggested that the blood pressure was significantly higher than that displayed via the radial line. This was confirmed by direct aortic pressure measurement, a discrepancy of > 60 mmHg being found. The peripheral line was abandoned as a route of fluid administration at this point and anaesthesia progressed uneventfully. On removal of the surgical drapes the left forearm was observed to be very swollen and tense. Luckily the swelling of the affected limb abated over the ensuing 48 h with elevation alone. I concluded that the peripheral line had ‘tissued’ and a large proportion of the transfusion had extravasated under pressure leading to a ‘compartment syndrome’ externally compressing the radial artery and so artefactually decreasing the systolic blood pressure displayed on the monitor. The patient's arms were secured by using a drawsheet folded over the arm and tucked in, as in Kinnear and Scase's case; however, no previous attempt at venous cannulation had occurred in this patient's arm. I can only surmise that the use of the pneumatic pressure bag had resulted in the bursting of the peripheral vein, perhaps contributed to by the drawsheet compressing the vein proximally, leading to extravasation of fluid at high pressure with the resultant compression of the radial artery. I suggest that pneumatic pressure bags should not be used to increase the rate of transfusion into any peripheral line that cannot be observed easily by the anaesthetist. I would also suggest that when a folded drawsheet is used to secure the arms of a pateint prior to cardiopulmonary bypass, sufficient slack is left to allow for the inevitable swelling that may occur following CPB due to an increase in extracellular fluid.