Guided Imagery Helps Reduce Preoperative Anxiety, but Has Little Impact on Postoperative Outcomes
Abstract & Commentary
By Dónal P. O'Mathùna, PhD. Dr. O'Mathùna is Senior Lecturer in Ethics, Decision-Making & Evidence, School of Nursing, Dublin City University, Ireland; he reports no financial relationship to this field of study.
Synopsis: This study examined the effects of using guided imagery on head and neck patients undergoing outpatient surgery. Preoperative anxiety was reduced significantly, and pain at 2 hours postoperative, but not analgesic use, length of stay, or patient satisfaction.
Source: Gonzales EA, et al. Effects of guided imagery on postoperative outcomes in patients undergoing same-day surgical procedures: A randomized, single-blind study. AANA J 2010;78:181-188.
This study was conducted at the Medical Center at Wright-Paterson Air Force Base in Ohio. Participants were adult patients scheduled for outpatient surgery of the head and neck under general anesthesia. Forty-four patients agreed to participate and were randomized to one of two groups using computerized random number generation. Anxiety was measured on the morning of surgery, before the patients received any interventions or medications, and again after guided imagery and before being transferred to the operative suite. Anxiety and pain were measured with visual analog scales (VAS) and anxiety was also measured using a self-reporting tool.
Guided imagery was provided using a CD player and headphones, which led the patients through progressive relaxation and guided imagery. This phase lasted 28 minutes, while those in the control group were provided 28 minutes of privacy with no CD. Immediately prior to induction of anesthesia, a second CD was inserted which played "soothing biorhythmic music" combined with statements of positive encouragement. The CD player was stopped and removed immediately before surgery.
Postoperative data were collected in the postoperative anesthesia care unit (PACU) by a researcher who was blinded to patients' group assignment. One hour after surgery, pain was assessed. This was repeated at 2 hours along with patient satisfaction. Time of discharge from PACU and ambulatory procedure unit (APU) was based on when patients met discharge criteria, not when they actually left each unit. Amount of analgesia used was recorded.
Anxiety levels did not differ significantly between the two groups at baseline. Before going to the operative suite, those receiving guided imagery had significantly lower anxiety (P = 0.002). On the VAS, the average score in the guided imagery group fell from 25.32 mm to 11.86 mm. No significant differences were found in the amount of analgesia used intraoperatively, in the PACU, or in the APU. No significant differences were found for the amount of midazolam used. One hour postoperatively, pain scores for those in the guided imagery group were close to being significantly lower (P = 0.057) and were significantly lower at 2 hours (P = 0.041). Length of stay did not differ significantly in either the PACU (P = 0.055) or the APU (P = 0.265). Patient satisfaction did not differ between the two groups (P = 0.143). The authors concluded that guided imagery appears to show promise in decreasing preoperative anxiety and postoperative pain.
Commentary
A number of other studies have shown that surgery patients who use guided imagery can have reduced preoperative anxiety, reduced postoperative pain, shorter lengths of hospital stays, and increased overall patient satisfaction. Hypnosis has many similarities with guided imagery and has been found to reduce anxiety in surgery patients and positively impact several outcomes.1 Such outcomes are both beneficial for patients and could lead to reduced costs. However, not all studies of guided imagery have found statistically significant benefits in the outcomes measured.2 Most studies to date have been performed with surgeries requiring in-hospital stays, with few data available for ambulatory procedures. Thus, this study sought to examine the outcomes for patients undergoing outpatient surgical procedures.
The study was designed and reported well, with the main limitation being that it was single-blinded. Given the requirement for patient participation in guided imagery, it is not clear how patients could be truly blinded. However, the type of control used here had some limitations. A control in which patients were allowed to listen to music or other recordings, which are not designed to produce relaxation, could have tested whether the guided imagery process itself was contributing to changes. Having the patients wait in private without listening to any type of recording may not have been the best comparison. Adding a third group that listened to music would have been even more preferable.
Another limitation is that the study was conducted with a relatively small number of patients (44). Power analysis was used to determine how many participants were needed in each group. However, this was based on a study in which in-hospital length of stay was almost 2 days shorter in the guided imagery group compared to the control group (5.6 vs. 7.5 days). The difference in length of stay found in this outpatient study was 9 minutes, which is much smaller and was not significant. This suggests that the study may have been underpowered to detect the actual level of difference between the two groups on this particular outcome.
While this study shows that guided imagery significantly reduces preoperative anxiety in ambulatory neck and head surgery patients, significant benefits were not found for most postoperative outcomes. The researchers did not state what their primary outcome was, but implied they were interested mostly in the postoperative outcomes. The limitations of multiple hypothesis testing need to be taken into account with these results.
The reduction of preoperative anxiety may be beneficial in itself. The researchers comment that with the trend to same-day surgery, starting guided imagery days before surgery may not be feasible. However, they also noted that patients can learn to use guided imagery on their own. Therefore, a study could be carried out where patients were facilitated to start guided imagery on their own prior to surgery. Further research would be needed to see if longer use of guided imagery prior to surgery has additional benefits. If so, patients could be given copies of appropriate recordings to listen to on their own devices, or loaned portable devices.
Many different CDs, tapes, and books are available on guided imagery. The CDs used in this study were produced specifically for surgery patients and those undergoing general anesthesia by Healthy Visions in Oak Ridge, TN. Whether these results can be generalized to other guided imagery resources would need to be examined.
Reference
1. Gurgevich S. Clinical hypnosis and surgery. Altern Med Alert 2003;6:115-119.
2. Haase O, et al. Guided imagery and relaxation in conventional colorectal resections: A randomized, controlled, partially blinded trial. Dis Colon Rectum 2005;48:1955-1963.
This study examined the effects of using guided imagery on head and neck patients undergoing outpatient surgery. Preoperative anxiety was reduced significantly, and pain at 2 hours postoperative, but not analgesic use, length of stay, or patient satisfaction.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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