Propofol 1% and propofol 2% are equally effective and well tolerated during anaesthesia of patients undergoing elective craniotomy for neurosurgical procedures.

BACKGROUND: The 2% formulation of the intravenous anaesthetic agent, propofol (Diprivan), delivers half the amount of lipid compared with the original 1% formulation. This may provide an acceptable alternative for patients who have an impaired ability to metabolise lipids. METHODS: This study was a multicentre, randomised, open comparison of parallel groups. Seventy-three adult patients undergoing elective craniotomy in neurosurgery were randomised to receive either propofol 1% (10 mg/ml) or propofol 2% (20 mg/ml) for induction and maintenance of anaesthesia. RESULTS: Analysis of induction time (199 s, 1%; 202 s, 2%; p > 0.05) and induction dose (1.13 mg/kg, 1.12 mg/kg; p > 0.05) shows that propofol 1% and propofol 2% are pharmacodynamically equivalent. Both formulations were similar regarding overall administration rates, recovery times, haemodynamic variables and tolerability. Plasma triglyceride levels, were lower in the propofol 2% group compared with the propofol 1% group, and significantly lower (p < 0.05) from 1 to 4 hours after induction. CONCLUSIONS: We conclude that propofol 2% is as effective and as well-tolerated as propofol 1% for anaesthesia and is an acceptable alternative to propofol 1% in patients undergoing elective craniotomy in neurosurgery. The lower lipid load suggests it may be of particular benefit to patients with disorders of lipid metabolism.

[Increasing the pressure of cerebral perfusion to control intracranial pressure]. / Aumentare la pressione di perfusione cerebrale per controllare la pressione intracranica.

ICP control can be achieved removing the surgical masses and manipulating the intracranial compartments; in the intensive care setting that can be attempted using CSF withdrawal or changing the cerebrovascular resistances, the intracranial blood content and the cerebral water content. The reduction of the ICP and the maintenance of a good cerebral perfusion pressure are the main aims of the therapy; when any standard treatment fails to control ICP a further attempt to preserve cerebral perfusion should be done by increasing the mean arterial pressure. In 10 patients with severe brain damage (GCS on admission ranging from 3 to 7, mean 5) from subarachnoid hemorrhage (3 cases) or trauma an infusion of dopamine (25-150 mg/h) and noradrenaline (0.4-2.4 mg/h) was started in case of intractable ICP. The ICP was defined intractable when the pressure was more than 40 mmHg for more than 5 m' after maximum therapy, as evaluated using the Therapy Intensity Level score. The infusion obtained a raise of the MAP of approximately 25% and a variable response on ICP. In 9 cases ICP dropped, in one case, instead, the ICP increased together with the arterial pressure. The reduction of ICP was 20-30%, with a good improvement of the CPP. The patients with a good response survived, the only patient without control of the ICP died. The physiopathologic mechanisms of this treatment are discussed; the most suitable explanation is indicated in an autoregulatory process. The infusion of cathecolamines can be harmful, and the patients eligible for this treatment must be carefully chosen. Notwithstanding this approach deserves further studies for the cases of intractable ICP.

[Arterio-jugular difference of oxygen and intracranial pressure in comatose, head injured patients. I. Technical aspects and complications]. / Differenza artero-giugulare di ossigeno e pressione intracranica nei traumi cranici in coma. Parte I: Aspetti tecnici e complicanze.

The monitoring of the comatose head injured patients is based on the recording of several data; the intracranial pressure measurements (ICP), associated with the arterial pressure recording, gives a good estimate of the cerebral perfusion pressure (CPP) but further information about the cerebral perfusion are needed. Based on the assumption that the cerebral metabolic rate is kept constant strong relationships exist between the cerebral blood flow (CBF) and the arterovenous difference of oxygen (AVDO2). In order to obtain samples of cerebral venous blood a catheter must be inserted in the internal jugular vein (IJ) with the tip of the cannula reaching the superior jugular bulb. In 224 patients we measured the ICP trough ventricular or subdural catheters; invasive measurement of the arterial pressure was also carried on in all the patients. In 45 patients we measured the AVDO2 and we tested the safety and the reliability of the jugular vein cannulation. During the insertion of the jugular catheters a slight increase of ICP, without any clinical significance, was recorded; in two cases (on a total of 45) accidental carotid puncture occurred. In 9 cases we tested the concordance of the oxygen content between the two IJs; looking at the mean values no statistical difference is detected between the two sides but in some cases relevant differences are recorded. In two cases we inserted the catheters more cranially, reaching a sinus of the cranial basis; the blood collected from these points carries less oxygen that the blood collected in the neck. The rate of infection in this series of ICP monitoring is very low (1.78%) and we had no bleeding at the moment of the insertion of the catheters. Since no significant complications related to the IJ cannulation were recorded we conclude that these techniques are safe and can be easily performed in the clinical setting. Further studies are required in order to investigate the clinical meaning of the differences in the IJs content of oxygen.

[Cerebral perfusion pressure in endocranial hypertension in comatose head-injured patients]. / Pressione di perfusione cerebrale ed ipertensione endocranica nei traumi cranici in coma.

The aim of the intensive care of the injured is the coupling of the availability and the requirement of the cerebral metabolic substates. The measurement of the cerebral blood flow is not currently available at the bedside and less direct monitoring is required. The cerebral perfusion can be estimated looking at the cerebral perfusion pressure (CPP), that can be easily measured using intracranial pressure (ICP) and the systemic arterial pressure (MAP) monitoring. Hundred-twenty-one consecutive head injured admitted to an Intensive Care Unit were studied assessing the severity of the neurological injury, the CT-Scan diagnosis of the intracranial lesion, the Trauma Score and the behavior of the ICP and MAP. The outcome was classified according to a modified version of the Glasgow Outcome Scale. More than 77% of the patients suffered raised intracranial pressure above 20 mmHg and 16 of them had a CPP less than 60 mmHg for more than 5 minutes. The outcome was directly related to the degree of intracranial hypertension and to the severity of insufficient CPP. The treatment of the severe head injured must be aimed at maintaining a good CPP, because of the close relationships between this value and the prognostic result. The monitoring of the ICP is a reliable and relatively safe procedure in this series, where the rate of infections complicating the intracranial recording is less than 3%.