Remifentanil vs fentanyl with a target controlled propofol infusion in patients undergoing craniotomy for supratentorial lesions.

AIM: Remifentanil hydrochloride is an ultra-short acting m-opioid receptor agonist. This study compared the use of remifentanil with that of fentanyl during elective supratentorial craniotomy in a target controlled infusion (TCI)-propofol anesthesia regimen and evaluated the quality of recovery from anesthesia. METHODS: After written informed consent for this prospective study, 40 adult patients were randomly divided into 2 groups: in group F analgesia was provided with fentanyl 2-3 mg kg(-1) h(-1) and in group R with remifentanil 0.25 mg kg(-1) h(-1). Anesthesia was induced with thiopental and pancuronium bromide, and maintained with propofol-TCI, pancuronium, air and oxygen and fentanyl (group F) or remifentanil (group R), respectively. After tracheal intubation, infusion rate of remifentanil was reduced and then adjusted to maintain stable hemodynamics. Hemodynamics and recovery time were monitored for 60 min after surgery. Analgesic requirements, propofol intraoperative consumption, nausea and vomiting in postoperative period were monitored. Recovery was evaluated according to a modified Aldrete score. RESULTS: Baseline hemodynamics were similar in both groups. Mean arterial pressure differed between the 2 groups (P<0.05) with the greatest decrease in group R during dura opening (P<0.001). Postoperative mean arterial pressure was higher in group R. Patients in group R exhibited a faster recovery. The incidence of nausea and vomiting was similar in the 2 groups. Noteworthy, there was a reduction in the amount of propofol used in group R. CONCLUSIONS: Remifentanil appears to be a reasonable alternative to fentanyl during elective surgery of supratentorial lesions.

Propofol EEG burst suppression in carotid endarterectomy.

BACKGROUND: The results of randomized trials indicate that carotid endarterectomy, performed with a low morbidity-mortality perioperative risk, is the best therapeutic option both for patients with high-grade symptomatic and asymptomatic stenosis. Since the main operative risk is represented by embolic or hemodynamic cerebral ischemia, it appears necessary to maintain an adequate intraoperative cerebral blood flow and to carry out a meticulous endarterectomy. METHODS: On the basis of these considerations we prospectively studied a series of 100 consecutive patients operated on for high-grade carotid stenosis, by using a protocol based on: 1) an accurate selection of patients for surgery; 2) meticulous surgical technique without any shunt; 3) perioperative cerebral protection by barbiturate or propofol; 4) pre- and postoperative medical treatment of risk factors. All patients of our series performed preoperatively brain CT scan, transcranial Doppler, carotid duplex scanning, four vessel angiography, brain 99mTc-HMPAO SPECT. Eighty-two patients had symptomatic carotid stenosis ranged between 70 and 90%, 18 had carotid stenosis higher than 90%. RESULTS: In this series there have been one postoperative death due to myocardial infarction and one major stroke. CONCLUSIONS: We think that this protocol can significantly minimize risks of endarterectomy and probably maximize the benefits of surgery, also in patients with asymptomatic high-grade carotid stenosis.

Hypertonic saline solution: a safe alternative to mannitol 18% in neurosurgery.

BACKGROUND: To evaluate the usefulness of hypertonic saline solutions (HTS) as an alternative to mannitol in neurosurgery. METHODS: Thirty patients subjected to craniotomy for supratentorial cerebral tumors were randomly divided in to three Groups: M: had mannitol 0.5 g.kg-1 as bolus at the start of skin incision, and postoperatively 0.5 g.kg-1 daily three times a day for 3 days (72 hrs); HM: had mannitol 0.25 g.kg-1 as bolus at the start of skin incision plus 3% HTS, 20 ml.h-1 intraoperatively and mannitol 0.25 g.kg-1 daily three times a day for 3 days plus HTS in the concentration of 3% in the first day and 2% and 1% the second and the third day after surgery; H: had 3% HTS 3.5 ml kg-1 as bolus at the start of skin incision plus 3% HTS, 20 ml hr-1 intraoperatively and 3% HTS, 20 ml h-1 on the first day and 2% and 1% the second and the third day after surgery. FR, MAP, ICP, CVP and diuresis were continuously monitored intraoperatively and postoperatively for 72 hrs. ICP was monitored intraoperatively until dural opening and in the postoperative period for 72 hrs at least. RESULTS: Diuresis was increased in the first and second Group (M and HM) more than in the H Group especially in the postoperative period, but this change was not a significative one (35.31 ml.kg-1.h-1+/-4.57 and 36.56+/-3.92 vs 3.23 ml.kg-1.h-1). Mean serum Na+ values declined in the postoperative period, in Groups M and MH and remained stable in the postoperative period in the Group H (137.6+/-7 mEq.l-1 and 136.5+/-6.5 mEq.l-1 vs 139.2+/-5 mEq.l-1). Serum osmolality increased significantly in the postoperative period in group H and remained unchanged in the same period in Group M and MH. Potassium values declined significantly during the whole period in all groups but remained in a normal clinical range. CVP values decreased in Groups M and MH in the postoperative period, and increased although not significantly in the postoperative period in the Group H patients. Ht values declined significantly in all groups without differences among the groups although the reduction was greater in group H. CONCLUSIONS: HTS can safely be used in humans they obtain a reduction of ICP without reducing CVP, serum osmolality and Na+ serum values. Our data underline the possibility of their use as an alternative to mannitol in the treatment of patients scheduled for intracranial surgery, especially when multiple doses are needed.

[The measurement of osmolality in neurologic intensive care]. / La misurazione dell'osmolalità in neurorianimazione. Nota tecnica.

Serum osmolality is one of the end-points in the management of neurologic intensive care patient. Its leading role in the concept of cerebrovascular homeostasis is underlined. Normal plasma osmolality is generally 285 mOsm kg-1, a value determined almost entirely by small molecules and ions (Na+, K+, urea and lactate). The plasma osmolality value is determined by measuring the changes in freezing point related to the zero value of a sample of distilled water. The measurement of plasma osmolality is very easy and inexpensive; its widely use could be very useful in the neurologic intensive care units to improve the treatment of neurological critical patient. According to the authors the monitoring of plasma osmolality should be mandatory to evaluate the effectiveness of treatment of brain edema.

[Subarachnoid hemorrhage and systemic arterial pressure. Physiopathology and perioperative management]. / Emorragia subaracnoidea e pressione arteriosa sistemica. Fisiopatologia e gestione perioperatoria.

A correct assessment of arterial pressure state during subarachnoid haemorrhage (SAH) is one of most critical issue in neurologic intensive care and in neuroanesthesia. It is important to evaluate two different clinical conditions during SAH: before and after aneurysmal clipping or embolization. Before clipping it is mandatory to evaluate a possibility of rebleeding and so it is important to maintain systolic pressure at lower level. Otherwise after clipping it can be useful to maintain systolic pressure at higher level to prevent vasospasm and related ischemia. In this review the Authors examine the pathophysiology of SAH and SAH complications as rebleeding, vasospasm and ischemia. According to international data, they propose pressure parameters appropriated for SAH according to timing of treatment so as to prevent and treat SAH complications.

Cerebrovascular reactivity before and after carotid endarterectomy.

BACKGROUND: The hemodynamic relevance of internal carotid artery (ICA) stenosis often does not correlate with anatomic features, as angiographically defined. The cerebrovascular reactivity (CVR) has been advocated as a means of defining the cerebral hemodynamic impairment. METHODS: We assessed the results of pre- and postoperative CVR evaluation, using the CO2 transcranial doppler method, in 25 patients with high-grade ICA stenosis. The patients with history of stroke, evidence of cerebral CT infarction or symptoms from the contralateral circulation or the brain stem were excluded to avoid the effects of cerebral infarction on the hemodynamic studies. Statistical analysis was used to evaluate the CVR changes after carotid endarterectomy. RESULTS: Preoperative evaluation showed that CVR was generally well correlated with the degree of ICA stenosis and concomitant contralateral carotid steno-occlusion. Before endarterectomy the mean CVR value was 66.5% (moderately reduced). After surgery the overall mean value of CVR was 84.1% (normal), with a statistically significant improvement. CONCLUSION: The results of this study suggest that the CVR evaluation allows one to obtain hemodynamic information of clinical interest in the patients with ICA stenosis and that carotid endarterectomy is effective to restore the CVR in patients with cerebral hemodynamic impairment.

[Appropriate arterial pressure management for subarachnoid hemorrhage ]. / Regime pressorio arterioso appropriato per l'ESA.

A correct assessment of arterial pressure state during SAH is one of most critical issue in neurologic intensive care. It is important to evaluate two different clinical conditions: a) during SAH when the aneurysm is open, b) after aneurysmal clipping or embolization. The authors propose pressure parameters appropriated for SAH according to the timing of treatment so as to prevent and treat SAH complications.

[Total intravenous anesthesia in neurosurgery. Our clinical experience]. / Anestesia endovenosa totale in neurochirurgia. Nostra esperienza clinica.

BACKGROUND: The quality of a "neuroanesthetic" technique is the result of its pharmacokinetics, of its effect on intracerebral homeostasis and metabolism, of its antinociceptive and neuroprotective features. Aim of this study is to test the effectiveness of TIVA as the technique of choice in neurosurgical patients throughout a retrospective analysis of 1982 patients scheduled for brain tumors, neurovascular surgery and spine lesions. METHODS: 1982 patients (1023 F, 959 M), ASA I-IV, aging 15-80 yrs scheduled for neurosurgery were studied. Hemodynamic and electrophysiological parameters were monitored carefully. Time of recovery was evaluated although this parameter is influenced by perioperative clinical status and by area and kind of brain damage. RESULTS: A good hemodynamic stability was observed. Recovery time was quick, related with brain damage and time of surgery. Incidence of postoperative nausea, vomiting and seizures was very low. Two cases of awareness were noted. CONCLUSIONS: 1982 neurosurgical operations were carried out in TIVA without major complications and side effects: the authors are therefore sure that TIVA can be considered the anesthetic technique "of choice" in neurosurgical patients.

Early percutaneous endoscopic gastrostomy (PEG). A safe and effective enteral feeding technique in neurologic intensive care unit.

Enteral feeding by percutaneous gastrostomy is recommended as the "best choice" in NICU patients. It allows us to obtain early gut activation and to prevent physiopathologic events leading to multiorgan failure syndrome. In this retrospective study the Authors describe their experience related to 76 patients admitted in NICU between January 1992 and April 1994. In these patients percutaneous gastrostomy was easily and safety performed at the bedside with early enteral nutrition and drug administration and a related low incidence of infections complicating central and peripheral vein catheterization. Moreover the authors underline the avoidance of nasogstric tube and its side effects and a good compliance of patients and nurses that seems to be a real advantage of this technique. The authors suggest their 13 guidelines to improve management of enteral nutrition by gastrostomy and to avoid its short-comings.

Accidental intrathecal injection of ionic water-soluble contrast medium: report of a case, including treatment.

We report a patient who inadvertently received a small amount of meglumine diatrizoate intrathecally. The physiopathology and treatment of this kind of accident are discussed.

99mTc HM-PAO brain perfusion SPECT in brain death.

Diagnosis of brain death must be certain to allow discontinuation of artificial ventilation and organ transplantation. Brain death is present when all functions of the brain stem have irreversibly ceased. Clinical and electrophysiological criteria may be misinterpreted due to drug intoxication, hypothermia or technical artefacts. Thus, if clinical assessment is suboptimal, reliable early confirmatory tests may be required for demonstrating absence of intracranial blood flow. We have easily carried out and interpreted 99mTc HM-PAO SPECT in a consecutive series of 40 comatose patients with brain damage, without discontinuing therapy. Brain death was diagnosed in 7 patients, by recognising absence of brain perfusion, as shown by no intracranial radionuclide uptake. In patients in whom perfusion was seen on brain scans, HM-PAO SPECT improved assessment of the extent of injury, which in general was larger than suggested by CT.

Tc-99m HMPAO SPECT in a cerebral gunshot wound.

The authors examined regional cerebral blood flow by using Tc-99m HMPAO SPECT studies in a patient who received a gunshot wound to the brain. Although the presence of the retained bullet's fragments adversely affected the quality of CT images and contraindicated MRI studies, the SPECT examination did not have the same constraints and allowed both therapy assessment and prognostic evaluation. The repair of the cortical defect could also be assessed.

Considerations of brain death on a SPECT cerebral perfusion study.

Brain death imaging is often a diagnostic challenge. Cerebral angioscintigraphy is extensively used for this analysis, but this test does not allow the perfusion evaluation of the posterior fossa. The authors report a case in which a SPECT study showed persistence of blood flow in infratentorial structures with total absence of cerebral (supratentorial) perfusion. This finding excluded the diagnosis of brain death.

[Brain death: physiopathology and current diagnostic approach]. / Morte cerebrale: fisiopatologia ed attuali orientamenti diagnostici.

The concept of death has undergone many changes in the centuries depending on ages and social contexts. However death has always been identified by heart and respiratory irreversible arrest. In the last 30 years this concept has been suddenly and deeply modified by cardiocirculatory and respiratory support techniques. The real boundary between life and death is cerebral activity. When this latter causes the subject can be considered dead. In the large majority of cases the clinical and this strumental neurological findings are sufficient for the diagnosis of brain death. However in many other cases this diagnosis may be difficult because of problems in the ascertainment of the complete and irreversible lack of cerebral activities. In these cases many an strumental techniques (evoked potentials, Doppler and nuclear medicine studies) can help in the diagnosis.