Intracranial pressure (ICP) was measured during induced hypotension with increasing doses of adenosine triphosphate (1-5 mg X kg-1 X min-1 ATP) in dogs without (group I) and with (group II) intracranial hypertension. After administration of 1 mg X kg-1 X min-1 ATP, ICP increased significantly from 11 +/- 4 mm Hg to 14 +/- 5 mm Hg (mean +/- SEM) (P less than 0.05; group I) and from 27 +/- 2 mm Hg to 38 +/- 6 mm Hg (P less than 0.05; group II), while mean arterial pressure (MAP) decreased from 103 +/- 10 mm Hg to 86 +/- 6 mm Hg (P less than 0.05; group I) and from 110 +/- 11 mm Hg to 90 +/- 11 mm Hg (P less than 0.05; group II). In both groups a slow decrease of ICP after the initial increase occurred with further lowering of MAP, but ICP remained significantly above control values even with a dose of 5 mg X kg-1 X min-1 ATP (P less than 0.05). Ventricular volume-pressure response curves (VPR) before and during intravenous infusion of 3 mg X kg-1 X min-1 ATP were constructed to determine changes in intracranial compliance (ICC). In both groups I and II ATP decreased ICC. On the basis of these results it is recommended that in the presence of intracranial mass lesions ATP should not be given to induce arterial hypotension before the dura is opened.
The influence of nifedipine induced hypotension on intracranial pressure (ICP) and intracranial compliance (ICC) was investigated in dogs without (group I, n = 8) and with (group II, n = 8) intracranial hypertension. ICP in group II was raised by gradual inflation of an epidurally placed balloon catheter. A volume-pressure-response curve (VPR) was established before and during the administration of nifedipine. In group II dogs angiotensin was infused before and during infusion of nifedipine in a dose sufficient to raise mean arterial pressure (MAP) by 30-40 mm Hg. An infusion of nifedipine (2 micrograms X kg-1 X min-1) subsequent to a bolus injection of nifedipine (10 micrograms X kg-1) resulted in a significant and sustained decrease in MAP (p less than 0.05) by 25% and 35% resp. due to a significant reduction in total peripheral resistance (p less than 0.05). ICP increased from 8.7 +/- 3.0 mm Hg to a maximum of 12.5 +/- 5.2 mm Hg in group I animals (p less than 0.05) and from 19.8 +/- 2.6 mm Hg to 24.8 +/- 7.2 mm Hg not significantly in group II dogs. The pressure-volume-index revealed a slight reduction of ICC in group I and a slight increase of ICC in group II resp. during nifedipine as compared to before nifedipine. When angiotensin was being administered in group II dogs before nifedipine was given, MAP increased by 40 +/- 5.8 mm Hg while ICP did not change significantly (+2 +/- 2.4 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)
The state of the art of autologous blood transfusion is described with special emphasis on safety aspects, indications and medicolegal implications.Literature was retrieved using the MEDLINE literature database. Medical and legal expert opinions on autologous blood transfusion programmes are presented as well as the actual German jurisdiction. Guidelines for autologous predeposit and haemodilution used in the University of Münster are described.In the past decade all forms of autologous transfusions gained increasing influence in haemotherapy due to the ongoing discussion on the safety of blood products. The German Federal Court has demanded that whenever homologous perioperative transfusion is considered likely, patients have to be offered autologous predeposit. Legal conditions for autologous programmes directed by anaesthetists not specialised in transfusion medicine are described. Whole-blood predeposit should be limited to two autologous units. In cases with minor blood loss, isovolaemic haemodilution may be performed instead of autologous predeposit. However, autologous transfusions have their specific risks that are either related to the patient or to the procedure of autologous predeposit, e.g., clerical error, contamination of blood products and technical faults. Standard procedures of the University of Münster to ensure low-risk autologous transfusion are presented. They consist in adequate handling and proper identification, testing of donor for virus infection markers, bacterial culture from blood products and a list of contraindications: anaemia, unstable angina, myocardial infarction within 3 months, decompensated heart insufficiency, aortic valve stenosis with angina, and cases with infection and fever.The risks related with autologous transfusion should be lower compared to homologous transfusions. Well-defined standards concerning indications and techniques are required to reach this goal.
