Effects of Fentanyl and S(+)-ketamine on Cerebral Hemodynamics, Gastrointestinal Motility, and Need of Vasopressors in Patients With Intracranial Pathologies

Abstract

In neurosurgical patients, opioids are administered to prevent secondary cerebral damage. Complications often related to the administration of opioids are a decrease in blood pressure affording the use of vasopressors and intestinal atonia. One alternative approach to opioids is the application of S(+)-ketamine. However, owing to a suspected elevation of intracranial pressure (ICP), the administration of S(+)-ketamine has questioned for a long time. The aim of the present study was to evaluate ICP, gastrointestinal motility, and catecholamine consumption in neurosurgical patients undergoing 2 different protocols of anesthesia using fentanyl or S(+)-ketamine. Twenty-four patients sustaining traumatic brain injury or aneurysmal subarachnoid hemorrhage received methohexitone plus either fentanyl or S(+)-ketamine to establish a comparable level of sedation. To reach an adequate cerebral perfusion pressure (CPP), the norepinephrine dosage was adapted successively. Enteral nutrition and gastrointestinal stimulation were started directly after admission on the critical care unit. ICP, CPP, and norepinephrine dosage were recorded over 5 days and also the time intervals to full enteral nutrition and first defecation. There was no difference regarding ICP, CPP, and the time period until full enteral nutrition or first defecation between both groups. Patients who underwent analgesia with S(+)-ketamine showed a trend to a lower demand of norepinephrine compared with the fentanyl group. Our results indicate that S(+)-ketamine does not increase ICP and that its use in neurosurgical patients should not be discouraged on the basis of ICP-related concerns.

Intubation of the Neurologically Injured Patient

“…These results have been called into question in the last 20 years because there are no data supporting these conclusions, and the original case reports had no comparison control group. Most research has supported that ketamine has a neutral or beneficial effect on CPP in patients with TBI and other neurologic insults (48)(49)(50)(51)(52)(53).…”

“…Although there is a regularly taught principle that ketamine will cause patients to become hypertensive and tachycardic, multiple studies have examined the use of ketamine for sedation and induction for RSI and found that ketamine, alone or in combination with other drugs, maintains hemodynamic neutrality without causing severe hypertensive or tachycardic responses (50,(57)(58)(59)(60)(61)(62)(63)(64).…”

A standardized rapid sequence intubation protocol facilitates airway management in critically injured patients

“…A small decrease in ICP with no change in mean arterial pressure or CPP was noted. 20 Schmittner et al 21 compared ketamine to fentanyl in combination with methohexitone for sedation in 24 ventilated intensive care unit patients with traumatic brain injury or aneurysmal subarachnoid hemorrhage. Patients who received ketamine had a tendency to require less norepinepherine to maintain CPP and did not have elevated ICP.…”

Maintaining comfort, cognitive function, and mobility in surgical intensive care unit patients

“…84 Finally, in extreme circumstances, ketamine for analgesia in the ICU may be warranted, although there are no Level I studies specific to ICU. 85,86 Sedation In addition to adequate analgesia, a smaller proportion of patients will require the addition of medication for sedation. In general, when sedation is required, light sedation is preferred.…”