The Effects of Preoperative Anxiety on Intravenous Sedation. DISCUSSION

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15 Sep 2009

The Effects of Preoperative Anxiety on Intravenous Sedation DISCUSSION

In this study, our goal was to assess the relationship between the total amount of sedative medications necessary for intravenous sedation and the level of preoperative anxiety, while controlling for the level of sedation in patients undergoing third molar extraction. We also assessed the relationship between preoperative anxiety and the degree of patient’s intraoperative movement.

The levels of midazolam and fentanyl administered to each patient were constant due to the adjustment of doses based on weight. Only one patient required an additional dose of midazolam after the initial sedation. This was due to an inability to get a deeper level of sedation (BIS reading below 80) without administering extra midazolam. The administration of propofol was given on an individual basis with use of BIS analysis to help control for the level of sedation. buy cialis super active

Past studies have looked at the relationship between anxiety and intraoperative anesthetic requirements. Maranets and Zeev studied the effects of preoperative anxiety on intraoperative anesthetic requirements for patients undergoing general anesthesia for bilateral laparoscopic tubal ligation. They found that state anxiety (measured by the STAI) is not associated with increased intraoperative anesthetic requirements, but trait anxiety serves as a predictor of increased intraoperative anesthetic requirements.

In the current study, we found that both state and trait anxiety served as predictors of increased intraoperative anesthetic requirements. There are procedural differences between the study by Maranets and Zeev and the current study and therefore different degrees of intraoperative stimulation. The anesthetic techniques are also very different in the study by Maranets and Zeev compared with the current study (general anesthesia vs intravenous sedation, respectively). In the study by Maranets and Zeev, general anesthesia with endotracheal intubation was achieved, as well as a greater depth of anesthesia (BIS reading of 40-60). It is possible that the difference in anesthetic techniques and degree of anesthesia between the study by Maranets and Zeev and the current study are the reason for the different results. The greater depth of anesthesia in the study by Maranets and Zeev may have led to a masking of the effects of state anxiety on anesthetic requirements, whereas in the current study, the lighter depth of anesthesia allowed the effects of state anxiety to be manifested.

Goldman et al studied preoperative anxiety in relation to intraoperative anesthetic requirements of alfen-tanil and methohexitone in women undergoing general anesthesia for gynecological surgery. This study reported increased anesthetic requirements correlated with increased state anxiety, but the results were nonsignificant, whereas in the present study the findings were significant. In the study by Goldman et al, there was no control for the depth of anesthesia, the type of proce­dure was not constant, and there was no use of a validated measurement tool of state anxiety. In the present study, we were able to control for the depth of anesthesia and type of procedure, as well as using a validated tool to measure state anxiety. Viagra Super Active

The present methods used to measure the level of patient sedation are often based on the subjective observation of the anesthetist, and clinical scoring methods are commonly used (eg, the Observers Assessment of Alertness/Sedation). Other methods, such as the electroencephalogram, are highly complex and difficult to interpret. By using subjective or highly complex means to assess depth sedation, it is difficult to determine exact anesthetic requirements and to maintain a constant level of sedation.

In this study, we chose to use BIS analysis to control for the level of sedation. The application of BIS technology to the field of anesthesiology has helped to gain real-time information into some of the complex changes that occur in the brain secondary to the use of sedative medications. Specifically, BIS analysis has been demonstrated to be useful as a pharmacodynamic measure of the level of responsiveness of the patient (ie, response to verbal command, gentle stimulation, painful stimulation) and particularly sensitive in predicting the loss of consciousness. Although few studies have been performed on sedated patients, BIS analysis has been noted to correlate with the clinically observed level of sedation in those patients. Use of BIS analysis allows for comparison of the amounts of sedative medications necessary to maintain the same hypnotic state or level of sedation.

By using BIS analysis, real-time information is available relative to the level of hypnosis, and there is no need to stimulate the patient to subjectively assess the level of sedation. In the current study, not having to stimulate the patient to assess the depth of sedation was advantageous because one of the variables looked at was the amount of intraoperative movement. viagra jelly online

In 1996, Ellis assessed the effects of preoperative anxiety on the amount of intraoperative movement and cooperation of patients undergoing intravenous sedation with midazolam for dental procedures. This study showed that only 49% of the subjects in the highest anxiety group were in the most favorably cooperative group (IV1). The study also showed that the least anxious subjects were in the most cooperative group (all of the least anxious in the IV1 group). Based on these studies, Ellis concluded that the more anxious a patient, the more likely he or she is to exhibit intraoperative movement and be less cooperative. In the present study, we showed that patients with high preoperative anxiety are significantly more prone to intraoperative movement. The shortcoming of the Ellis study is that it did not use a validated tool to measure anxiety, such as the STAI, which was used in the current study.

When we applied the STAI in the current study, we showed that trait and not state anxiety was a significant predictor of increased intraoperative movement. Perhaps trait anxiety is a predictor because it represents an individual’s underlying tendency to perceive a situation as hostile or dangerous. Perhaps state anxiety did not serve as a predictor of increased intraoperative movement because the level of sedation used in the procedures was sufficient to blunt the unwanted intraoperative movement.

For all patients in this study, all procedures were completed regardless of the degree of patient movement. In only 2 patients was it necessary to stop the procedure temporarily due to patient movement. These patients were given additional medication and the procedure was continued. One can anticipate that the patient’s degree of intraoperative movement would have an impact on the surgeon’s and the patient’s satisfaction with the procedure and sedation. One limitation of our study is that no formal assessment of patient and surgeon satisfaction was performed. buy zyrtec

There are some other limitations in our study design that must be addressed. In the sedation procedure, a per body weight dosage schedule was used, which has been shown to be unreliable due to high interindividual variability. In the current study, there is also administration of either 10- or 20-mg boluses of propofol in response to an increase in BIS value (ie, in response to a decrease in depth of sedation). Many studies have demonstrated variability in the control of the level of sedation due to interindividual variability in the dose requirements of propofol. This variability in dose requirement may lead to oversedation and therefore a potential suppression of the response to anxiety and intraoperative stimuli. It was noted in the review of the results that some patients were not given additional propofol and were allowed to reach a lighter degree of sedation (BIS reading >80) just before the end of the procedure. Conversely, other patients received additional doses of propofol shortly before the end of their procedure, which may have led to suppression of the response to anxiety and increased recovery time. The benefit of using propofol in the sedation procedure of the current study is that if oversedation occurs, the optimal level of sedation can be restored quickly (usually within 1 minute) by decreasing the dosage.

Another disadvantage of the current study is the inherent variability in duration and complexity of third molar extraction procedures. Because of the variation in complexity, some cases will require more extensive bone removal or development of a flap. These variations will result in various degrees of surgical stimulation. To minimize the variation in the current study, we have only included subjects who are undergoing extraction of at least 2 impacted third molars. In this study, there were also different operators who performed the procedures. All operators were junior or senior oral and maxillofacial surgery residents at the same institution, and the same faculty member oversaw all procedures. One way to improve the study design would have been to have only one operator perform all procedures. generic singulair

The data suggest that a patient with an increased level of state or trait anxiety before a surgical procedure will require an increased amount of sedative medication to induce and maintain a clinically acceptable level of sedation. The data also suggest that the more anxious a patient in the preoperative period, the more prone he or she is to movement during the surgical procedure. By knowing that patients who are highly anxious will require more medication for sedation and are more prone to move during the procedure, we can use anesthetic techniques that will allow for deeper sedation to keep the patient comfortable and prevent potentially harmful intraoperative movement.

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Blog invites submissions of review articles, reports on clinical techniques, case reports, conference summaries, and articles of opinion pertinent to the control of pain and anxiety in dentistry.


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