Article
Effects of fentanyl and S(+)-ketamine on gastrointestinal motility and catecholamine dosages in neurosurgical patients – A pilot study
Einfluss von Fentanyl und S(+)-Ketamin auf gastroinstinale Motilität und Katecholaminbedarf in der Langzeitanalgosedierung neurochirurgischer Patienten - Pilotstudie
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Authors
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Marc Schmittner
- Institut für Anästhesiologie und Operative Intensivmedizin, Universitätsklinikum Mannheim, Medizinische Fakultät der Universität Heidelberg, Mannheim
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S. Renn
- Institut für Anästhesiologie und Operative Intensivmedizin, Universitätsklinikum Mannheim, Medizinische Fakultät der Universität Heidelberg, Mannheim
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P. Vajkoczy
- Klinik für Neurochirurgie, Universitätsklinikum Mannheim, Medizinische Fakultät der Universität Heidelberg, Mannheim
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M. Quintel
- Zentrum für Anästhesiologie, Rettungs- und Intensivmedizin, Universitätsklinikum Göttingen, Göttingen
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E. Münch
- Institut für Anästhesiologie und Operative Intensivmedizin, Universitätsklinikum Mannheim, Medizinische Fakultät der Universität Heidelberg, Mannheim
| Published: | April 23, 2004 |
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Outline
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Objective
In neurosurgical patients, narcotics are ususally administered to prevent secondary cerebral damage due to elevated intracranial pressure (ICP) and to provide conditions favouring the recovery of brain tissue. Intestinal atonia and a decrease in blood pressure affording the use of vasopressors, however represent complications often related to the type of anesthesia being used. The aim of the present study was to evaluate gastrointestinal motility and catecholamine consumption in neurosurgical patients undergoing two different protocols of anesthesia using fentanyl/methohexital, and S(+)-ketamine/methohexital.
Methods
Twenty-four patients (mean age 52±17 years) who sustained severe traumatic brain injury or aneurysmal subarachnoid hemorrhage received either fentanyl/methohexital or S(+)-ketamine/methohexital in a prospectively controlled randomized trial. In both groups, dosage of methohexital was 3mg/kgBW/h. Dosage of analgesia (fentanyl or S(+)-ketamine) was titrated to establish a comparable level of sedation, monitored by Bispectral-Index (BIS). ICP was treated according to the AANS guidelines. The dosage of norepinephrine was adapted to reach a cerebral perfuison pressure (CPP) of under 70 mmHg mmHg. BIS, ICP, CPP and norepinephrine dosage were recorded over 5 days. Indirect calorimetry was performed to determine the energetic requirements of each patient and enteral nutrition was started via a stomach tube following an increasing nutrition scheme. Metoclopramid, neostigmin and ceruletid were applied in a standardized fashion. In order to assess gastrointestinal motility, time intervals to full enteral nutrition and first defecation were recorded. Based on the results of this pilot study, sample size estimation was performed to evaluate the number of patients required to reach statistically significant differences.
Results
Patients, who underwent analgesia with S(+)-ketamine had a lower demand of norepinephrine compared with the fentanyl-group (3.6 ± 5.1 µg/kgBW/h vs. 12.8 ± 18.4 µg/kgBW/h). Sample size estimation revealed that 42 patients in each group would be required in order to demonstrate a significant difference regarding catecholamine consumption. In contrast, there was no difference between the two groups regarding the time period to achieve full enteral nutrition (85.3 ± 47.2 hrs vs. 94.4 ± 72.9 hrs) or time until first defecation (40.9 ± 22.9 hrs vs. 43.5 ± 46 hrs).
Conclusions
In patients receiving S(+)-ketamine, lower dosages of norepinephrine are needed to maintain an adequate CPP than in patients sedated with fentanyl. The influence of fentanyl and S(+)-ketamine on gastrointestinal motility is comparable.
