Comparative evaluation of oxygen saturation during periodontal surgery with or without oral conscious sedation in anxious patients.

CONTEXT: Stress and anxiety during dental procedure can alter respiratory rate and thereby alter oxygen saturation in the blood, leading to emergencies like syncope. It can be prevented by preoperative intravenous sedation. However, it can lead to respiratory depression. Hence, this study was carried out to analyze the effect of oral conscious sedation on oxygen saturation during periodontal surgery in anxious patients. AIM: The aim was to compare the oxygen saturation levels during periodontal surgery with and without oral conscious sedation using diazepam in anxious patients. SETTINGS AND
DESIGN: Randomized clinical trial.
MATERIALS AND METHODS: The study population consisted of 20 generalized periodontitis patients, identified as anxious for dental treatment with dental anxiety scale. A randomized split-mouth design was used with one quadrant of surgery involving preoperative oral sedation (diazepam), and the second without it. Oxygen saturation was monitored by pulse oximetry. Data were recorded at 5 time periods during the surgery. STATISTICAL ANALYSIS USED: Mann-Whitney U-test.
RESULTS: No statistically significant difference between sedated and nonsedated patients in oxygen saturation with P = 0.683.
CONCLUSIONS: Oral conscious sedation can be used for anxious patients during periodontal surgery for alleviation of anxiety and for better patient acceptance during surgical procedures without significant respiratory depression.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Anxiety for dental treatment is highly prevalent and it is up to 12-16% among the general population.[1] The prospect of surgery is a powerful anxiety provoking stimulus in the dental setting. The majority (71%) of patients anticipating periodontal therapy reported apprehension and fear of pending appointments and described themselves as highly anxious.[2] Dental treatment in such patients can lead to hyperventilation and vasodepressor syncope, which are commonly encountered emergency situations in dentistry. It is advisable to identify anxious patients before beginning the treatment with the help of different scales for measuring dental anxiety presented in the literature.[3] Corah's dental anxiety scale (DAS)[4] has been widely used for such purpose. Minimizing stress will certainly reduce the chance of medical emergency occurring during dental treatment. One of the methods in anxiolysis is conscious sedation. In depth knowledge in areas of sedation, and clinical training to all levels of adult sedation is necessary for every periodontist to offer standard care for the patient.[5] Moreover American academy of periodontology policy statement recommends the use of moderate sedation during the course of periodontal therapy.[6]

Conscious sedation is routinely used during various surgical procedures in dentistry. Few of the authors demonstrated that intravenous (IV) sedation has the risk of inducing hypoxia;[78910] hence IV sedation requires continuous monitoring of the patients. It would be very effective if similar anxiolysis is achieved by different method of sedation with minimal complications.

One such method is oral sedation. Most of the studies in periodontics deal with oxygen saturation levels during IV sedation. Hardly any data is available where patients are categorized as anxious are subjected for analyzing the oxygen saturation during dental procedures to evaluate its safety. Even though, around half of the periodontists in America use conscious sedation during periodontal practice,[11] studies related to its safety for dental practice are minimal. The present study intends to evaluate the safety of oral conscious sedation with diazepam using oxygen saturation levels as a parameter during periodontal surgery in anxious patients.

Aim of the study

To compare the oxygen saturation levels during periodontal surgery with and without oral conscious sedation using diazepam in patients anxious to periodontal surgical procedures.

MATERIALS AND METHODS

Screening procedures

Subjects were recruited from the Department of Periodontics A.B. Shetty Memorial Institute of Dental Sciences, Mangalore; for a double-blind study testing the oxygen saturation levels during periodontal surgery with and without oral diazepam. A placebo was used as a control. Simple random sampling was followed in this split-mouth technique.

Two hundred and fifty subjects of the age group 30-65 years diagnosed of generalized chronic periodontitis requiring periodontal surgery were screened for evaluating dental anxiety. A scripted interview was carried out for all of these candidates. The candidates were asked if they ever had any kind of dental surgery including extraction. A photo album of periodontal flap surgery was shown to each patient. Candidates were then asked if they preferred no sedation, some sedation, or complete sedation during the procedure. One hundred and eighty-eight candidates who claimed that they would not need a sedative during the flap surgery were excluded because of low fear levels. Patients with hypersensitivity to diazepam, existing central nervous system depression, narrow angle glaucoma, severe uncontrolled pain, pregnant ladies and patients taking antidepressants were excluded from study.

QUESTIONNAIRE SURVEY

All the 62 patients recruited by initial verbal analysis were asked to fill modified Corah's DAS [Figure 1]. This anxiety scale asks subjects to rate themselves on a scale of 1-5 on four parameters:

Figure 1

Modified dental anxiety scale

Anxiety about a hypothetical dental appointment that would occur the next day

Anxiety in a dentist's waiting room

Anxiety while waiting for drilling

Anxiety while waiting for a gum surgery.

Subjects scores are totalled (4-20) for analysis; a higher score indicates greater anxiety about dental procedures. A DAS score of 13 or higher indicates high dental fear.[4]

Twenty patients (10 males and 10 females), found to be of high dental fear based on DAS, were included in the study to evaluate oxygen saturation during periodontal surgery. Written informed consent was taken for participating in this study.

Study design

Twenty subjects requiring minimum two sextants of flap surgery were selected for the study. Each sextant was randomly assigned into experimental and control site. Modified widman flap surgery was performed in experimental site with preoperative oral diazepam sedation and local anaesthesia. Similar surgery was performed in control site with preoperative oral placebo and using local anaesthesia only. Identical placebo was prepared at Nitte Gulabi Shetty Memorial Institute of Pharmaceutical Sciences, Mangalore.

Consort diagram

Sedatives were given based on the body weight of the patient. Patients under 150 pounds were given 5 mg of diazepam and patients over 150 pounds are given 10 mg of diazepam, the evening before and 1-h before elective periodontal surgery.

Evaluation of oxygen saturation

Arterial oxygen saturation is measured as SpO2 in pulse oximeter. Drop in arterial saturation below normal (95-100% in coastal altitude) is indicated by ringing of its alarm. A mild hypoxemic episode can be defined as a SpO2 between 90% and 94%, a moderate hypoxemic episode between 85% and 89% and severe hypoxemia when <85%.

In this study oxygen saturation was monitored throughout the periodontal surgical procedure continuously by the use of pulse oximetry (Planet 50, Non Invasive Transport Monitor, Larsen & Toubro ltd, India). Number of times alarms rang was documented at 5 time periods. Severities of hypoxic episodes were observed.

Statistical analysis

The sample size was calculated by using the previous study Aeschliman et al. 14 the mean difference 1, standard deviation 1.35 with 95% confidence interval and power of the study was fixed to be 90%. By calculating all these we obtained 20 sample in each group.

Descriptive statistics were computed as mean and standard deviation. The Mann–Whitney U-test was used to test differences between groups of data that were not normally distributed. Qualitative data was measured by Chi-square test. The level of statistical significance was set at P < 0.05.

RESULTS

Twenty patients were selected for the study among 250 generalized chronic periodontitis patients requiring periodontal surgery. Selected patients were anxious of dental surgical procedure, based on thorough verbal enquiry and modified dental anxiety questionnaire [Figure 1].

Number of times oxygen saturation fell below 95%, in each patient in experimental and control group was subjected to Mann–Whitney U-test [Table 1]. The mean value shows about eight fold increased alarms in control group compared to experimental group. However no statistically significant differences were found between the two groups (P = 0.683).

Table 1

Comparison of oxygen saturation levels below 95% in experimental and control groups

We analyzed mean number of pulse oximetry alarms per time interval [Table 2]. We found increased tendency of hypoxia during 3rd and 4th time interval in both experimental and control groups, which is least in the last time interval corresponding to the termination of surgery. Howewer No statistically significant differences were found with Chi-square test (P = 0.979).

Table 2

Mean number of pulse oxymetry alarms per time interval

Table 3 shows severity of hypoxic episodes in experimental and control groups. It shows that maximum number of hypoxic events occurred during periodontal surgery in this study were in mild hypoxia.

Table 3

Severity of hypoxic episodes

DISCUSSION

Identifying the anxious patients and managing their fear is important aspect in dental surgical therapy. This prevents dental emergencies which are usually caused by psychological stress like syncope and patients non co-operation. In the present study dental anxiety was identified by oral interview and dental anxiety questionnaire. Out of two hundred and fifty patients, 20 patients were found to be anxious, accounting for 8% of the study population. This is nearly consistent with the previous study by Fardal and Hansen[12] which showed 12% anxiety for periodontal surgery.

Conscious sedation using oral route of benzodiazepines are increasingly used in combination with local anesthesia to control anxiety during invasive procedures of dentistry. Oral route possesses several advantages such as universal acceptance, ease of administration, low cost, decreased incidence of adverse reaction. Further, it does not require any specialized training as compared to parental route of sedation.

Various studies have demonstrated statistically significant incidence of hypoxia in patients undergoing surgical procedures with intra venous conscious sedation.[78910] This may be associated with inability of the patient to maintain patent airway leading to rapid decline in oxygen saturation under sedation, or directly because of respiratory depressant activity of these sedatives like benzodiazepines.[8910111213] This is the major limitation of IV sedatives and hence requires constant monitoring of these patients throughout the procedure with ready to access emergency drugs and equipments.

Our study evaluated the oxygen saturation levels in 20 anxious patients undergoing periodontal surgery. In a split-mouth technique they were operated one sextant each with or without conscious sedation using oral diazepam in two different appointments. Results showed that oxygen desaturation occurred totally 114 times during these 40 periodontal surgeries. Out of which only 13 desaturations occurred in the group which received oral conscious sedation. Remaining all desaturations occurred in nonsedated group. This value seems to be clinically very significant. But most of the desaturation values (i.e., 92 out of 101 pulse oximetry alarms) reported from only four patients out of twenty study population. We utilized Mann–Whitney U-test to evaluate the statistical significance of our study. The Z value of 0.40800 was obtained with P = 0.683 which is statistically not significant [Table 1] and this result is in agreement with similar study performed by Aeschliman et al.,[14] in which sedatives were given irrespective of their anxious levels. Thus it can be assumed that level of anxiety and oxygen desaturation does not have observable relations. It is seen that [Table 1] many patients did not encounter oxygen desaturation during periodontal surgery even though they were anxious.

This result contradicts previous studies reporting that patients sedated with diazepam had lower oxygen saturation levels during surgical procedures than patients without sedation.[89] However, there are fewer studies to compare oxygen saturation in periodontal surgery.[14] We agree the hypothesis that patients may be more sedated and relaxed during surgery, and thus may be more able to maintain a normal respiratory pattern than patients who are more anxious.[14] Sedated patients were very cooperative throughout the procedure in this study and it is in agreement with study by Shepherd et al.[15] Our study suggests that diazepam given orally in adult dosages does not cause respiratory depression and is safe to use for patients who require sedation during periodontal surgery.

During the study we noticed that, in the first surgical appointment anxious patients in conscious sedation group were relaxed and did not show any responses of anxiety compared to placebo group who showed fear for every step of periodontal surgery. But during the next visit patients in both the group were much relaxed.

We evaluated the number of pulse oximeter alarms per time interval [Table 2]. It shows increased tendency of hypoxia during 3rd and 4th time interval in both diazepam and nondiazepam groups. Hypoxia comes to minimum in the last time interval which corresponds to the termination of surgery. This is very important finding and it suggests that monitoring of the patients should be done during these time intervals (20-40 and 40-60 min) to minimize the chances of hypoxia in both the groups. The reason for this increased tendency for hypoxia could not be recognized, especially noting the limited number of patients in our study. However, we hypothesize that this may be associated with the timing of the surgery itself, as patients may become lethargic in the latter part of the surgical procedure, accounting for the increased number of hypoxic events in these time interval.

Monitoring the severity of hypoxia, we found that [Table 3] maximum cases of hypoxic events were of mild variety. Out of 114 hypoxic events, 90 were mild, 14 moderate and 10 were severe hypoxia. This shows minimal chances of severe hypoxia in periodontal surgical patients with or without conscious sedation. Thus within the limits of this study, it demonstrates adequate safety of oral conscious sedation.

Our study shows sedation can be achieved without much incidence of hypoxia with the use of oral diazepam during periodontal surgical procedure.

CONCLUSION

This study suggests that oral conscious sedation can be used for anxious patients during periodontal surgery for alleviation of anxiety and for better patient acceptance during surgical procedures. Study also indicates that oral conscious sedation does not cause hypoxia and it is safe to use it in anxious patients. It indicates that constant monitoring of patients undergoing periodontal surgery for oxygen desaturation should be done routinely in periodontal practice. We conclude that oral conscious sedation does not cause hypoxia and it is safe to use it in anxious patients.