[Analgesic dosage with (S)-ketamine/propofol vs. (S)-ketamine/midazolam: sedation, stress response and hemodynamics--a controlled study of surgical intensive care patients]

Deep sedation in GreenLight laser prostatectomy

Introduction:

Evaluation of ketamine and propofol combination for the performance of photoselective vaporization of prostate (PVP).

Patients and Methods:

Twenty-six patients undergoing PVP for benign prostatic hyperplasia were included in the study. Co-morbidities were present in 24 patients. Midazolam 2 mg intravenous was administered for the induction to anesthesia. Propofol (10 mg/ml) and ketamine (1 mg/ml) were administered with the use of two pumps. An initial bolus dose of 0.03 ml/kg of propofol and 5 mg of ketamine was administered intravenously. The anesthesia was maintained by continuous infusion of 0.01 ml/kg/min of propofol and 2 ml/min of ketamine. Fentanyl was administered when deemed necessary. The level of sedation, peri-operative parameters and side-effects were recorded.

Results:

The average periods from the induction of anesthesia and intraoperative infusion were 12.38 ± 5.84 min and 59.5 ± 22.15 min, respectively. Average propofol and total ketamine dose were 85.5 ± 10.62 μg/kg/min and 144.9 ± 45.62 mg, respectively. The average dose of fentanyl administered was 29.81 ± 27.40 μcg. An average period between the end of the infusion and the discharge to the urology clinic was 34.62 ± 22.89 min. Ten patients experienced nausea and five eventually vomited. Hallucinations were observed in five cases while visual disturbances in two patients.

Conclusion:

The combined use of ketamine and propofol for the performance of PVP proved to be an efficient method for anesthesia. The “deep sedation” provided by these drugs was not associated with significant side-effects. Moreover, the use of the above method is indicated in patients with significant co-morbidities that should undergo PVP.

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

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.

Revising a Dogma: Ketamine for Patients with Neurological Injury?

We evaluated reports of randomized clinical trials in the perioperative and intensive care setting concerning ketamine's effects on the brain in patients with, or at risk for, neurological injury. We also reviewed other studies in humans on the drug's effects on the brain, and reports that examined ketamine in experimental brain injury. In the clinical setting, level II evidence indicates that ketamine does not increase intracranial pressure when used under conditions of controlled ventilation, coadministration of a gamma-aminobutyric acid (GABA) receptor agonist, and without nitrous oxide. Ketamine may thus safely be used in neurologically impaired patients. Compared with other anesthetics or sedatives, level II and III evidence indicates that hemodynamic stimulation induced by ketamine may improve cerebral perfusion; this could make the drug a preferred choice in sedative regimes after brain injury. In the laboratory, ketamine has neuroprotective, and S(+)-ketamine additional neuroregenerative effects, even when administered after onset of a cerebral insult. However, improved outcomes were only reported in studies with brief recovery observation intervals. In developing animals, and in certain brain areas of adult rats without cerebral injury, neurotoxic effects were noted after large-dose ketamine. These were prevented by coadministration of GABA receptor agonists.

IMPLICATIONS

Ketamine can be used safely in neurologically impaired patients under conditions of controlled ventilation, coadministration of a {gamma}-aminobutyric acid receptor agonist, and avoidance of nitrous oxide. Its beneficial circulatory effects and preclinical data demonstrating neuroprotection merit further animal and patient investigation.

Analgesie und Sedierung in der Intensivmedizin

Sedation and analgesia are relevant aspects for the adequate treatment of patients in an intensive care unit. Recent drug developments and new strategies for ventilation provide improved sedation management allowing better adaptation to the clinical background and individual needs of the patient. This article provides an overview on the application of different substance groups. Focus is placed on newly developed pharmaceuticals such as dexmedetomidine. Another aspect is scoring system-related and EEG-based monitoring of depth of sedation. Modern concepts of analgesia and sedation for ICU patients have been developed based on the interaction of different parameters such as adaptive sedation and analgesia management (ASAM).