Intravenous nitroglycerin-induced intracranial hypertension

Adverse neurologic effects of medications commonly used in the intensive care unit

Adverse drug effects often complicate the care of critically ill patients. Therefore, each patient's medical history, maintenance medication, and new therapies administered in the intensive care unit must be evaluated to prevent unwanted neurologic adverse effects. Optimization of pharmacotherapy in critically ill patients can be achieved by considering the need to reinitiate home medications, and avoiding drugs that can decrease the seizure threshold, increase sedation and cognitive deficits, induce delirium, increase intracranial pressure, or induce fever. Avoiding medication-induced neurologic adverse effects is essential in critically ill patients, especially those with neurologic injury.

Nitroglycerin-induced migraine type headache: bilaterally visible temporal arteries

A 37-year-old man presented to the emergency department suffering from headache, nausea and vomiting, which had started 1 h previously. He had been diagnosed with coronary artery disease and had been taking isosorbid-5-mononitrate, aspirin and metoprolol for 3 days. His vital signs and physical and detailed neurological examinations were normal except for a new onset of bilaterally visible, palpable and pulsatile temporal arteries. We discuss how nitrates can increase the cerebral and also temporal blood flow, which can rarely be seen with the naked eye, as was observed in this patient.

Effect of Vasoactive Therapy on Cerebral Circulation

Many questions regarding blood pressure management after acute stroke remain unanswered, resulting in an ongoing debate about whether to treat hypertension acutely and how aggressively blood pressure should be lowered. This review discusses normal and altered cerebrophysiology and provides evidence supporting and opposing the active management of blood pressure within the first 24 hours after stroke. Commonly used intravenous antihypertensive agents and their cerebrovascular effects are reviewed, and therapeutic recommendations are given based on the available evidence.

Effects of nitroglycerine on cerebral blood flow velocity, quantitative electroencephalogram and cognitive performance

BACKGROUND

Despite the widespread use of nitroglycerine, little is known of its cerebral haemodynamic effects. The present study was undertaken to evaluate the effects of nitroglycerine on cerebral circulation and cognitive function in normal volunteers.

DESIGN

Twelve healthy male volunteers (age 25 +/- 3 years; mean +/- SD) received continuous intravenous infusions of nitroglycerine at 1 mg h-1 and 2 mg h-1 rates as well as placebo (0.9% saline) under randomized, double-blind cross-over conditions on three different occasions. A 10-min quantitative EEG (qEEG) was recorded before, during and repeatedly after infusion. Blood flow velocity in the left arteria cerebri media (MCA) was measured simultaneously by means of transcranial Doppler sonography. Cognitive performance was assessed with a computerized test battery.

RESULTS

Administration of nitroglycerine caused a significant reduction of mean blood flow velocity in the left MCA. In parallel a significant increase of absolute power density < 4 Hz was noted. The latter effect was dose dependent. Cognitive functions, such as attention and memory, were not altered.

CONCLUSIONS

The decrease in cerebral blood flow velocity in the left MCA may be due to vasodilatation and/or reduction in perfusion. The concomitant increase of slow wave power in the qEEG may indicate an impairment of brain function.

Propylene glycol-induced side effects during intravenous nitroglycerin therapy

Propylene glycol, an alcohol frequently used as a solvent in medical preparations, is considered non-toxic. We found that this solvent, used in a commercially available IV nitroglycerin solution, may cause hyperosmolality, hemolysis and lactic acidosis. The influence of kidney function as the main determinant in causing accumulation of this solvent and consequently hyperosmolality is emphasized. A review of the literature dealing with propylene glycol is given. The possible mechanisms of neurological disturbances occurring during IV nitroglycerin therapy are discussed.