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Egyptian Journal of Oral & Maxillofacial Surgery:
doi: 10.1097/01.OMX.0000438042.82272.88
Research Paper

Hemodynamics during intravenous conscious sedation: an institutional experience

Gadicherla, Srikantha; Kamath, Abhay T.a; Muthanna, Cariappa K.a; Bhagania, Manisha; Pentapati, Kalyana C.b

Free Access
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Author Information

Departments of aOral and Maxillofacial Surgery

bPublic Health Dentistry, Manipal College of Dental Sciences, Manipal, Karnataka, India

Correspondence to Kalyana C. Pentapati, MDS, Department of Public Health Dentistry, Manipal College of Dental Sciences, Manipal, 576104 Karnataka, India Tel: +91 991 603 6303; fax: +91 0820 2571966; e-mail: drkalyan81@gmail.com

Received October 22, 2013

Accepted October 23, 2013

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Abstract

Aim: Our study aimed to evaluate the hemodynamic parameters during conscious sedation.

Materials and methods: A retrospective study was carried out on 55 patients who had been treated for dental conditions under conscious intravenous sedation. Conscious sedation was performed either with propofol or midazolam with fentanyl. The local anesthetic (lignocaine) was administered once good sedation had been achieved in all patients with a vasoconstrictor. Data on blood pressure (BP), heart rate (HR), and oxygen saturation (SpO2) levels were obtained at 12 different levels.

Results: Only 48 patients had complete data on hemodynamic parameters. With respect to the mean HR, no significant difference was observed at baseline, at sedation, and at injection of the local anesthetic, whereas significantly higher mean HR was observed in the midazolam group at the time of incision, during the surgery, suturing, and recovery. The mean BP was significantly higher in the midazolam group at all the intervals. The mean SpO2 was significantly higher for midazolam at baseline, 20 min during the surgery, and during suturing. At all other intervals, there was no significant difference in the mean SpO2 between both groups. The mean HR varied with time in the propofol group, whereas no significant difference was observed in the midazolam group (P=0.027 and 0.108), respectively. The mean BP varied with time in both groups (P<0.001 and <0.001), respectively. The mean SpO2 varied with time in the midazolam group, whereas no significant difference was observed in the propofol group (P=0.033 and 0.177), respectively.

Conclusion: Both drugs appear to be safe and efficacious for intravenous conscious sedation.

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Introduction

Dental pain can lead to hemodynamic changes such as increased blood pressure (BP) or heart rate (HR), which can be controlled with a correct sedation technique. In dentistry, while performing long-duration surgical procedures, conscious intravenous sedation is an alternative additional option to local anesthesia 1. The term conscious sedation represents a drug-induced state in which the conscious patient is rendered free of fear, anxiety, and apprehension while remaining comfortably relaxed. Conscious sedation is not a method of pain control 2. The safety profile of intravenous conscious sedation by the anesthetist is good, with a low incidence of adverse events 3.

Alemany-Martínez et al. 4 evaluated the hemodynamic changes during the surgical removal of lower third molars, and concluded that most of the cardiovascular changes induced by surgical extraction of molars were within normal ranges. Parworth et al. 5 carried out a study with propofol and midazolam combined with fentanyl. They concluded that the differences in systolic and diastolic BP, HR, and oxygen saturation (SpO2) were not clinically significant, and no intervention was required, although the systolic and diastolic BP were significantly lower in both groups at the 5-min intraoperative period. Similarly, both groups showed a significant increase in HR at the 10-min and 15-min periods.

González-Lemonnier et al. 6 monitored hemodynamic and ventilator changes during implant surgery with intravenous conscious sedation using midazolam and fentanyl. They reported that the highest systolic and diastolic BPs were reported during incision and raising of the mucoperiosteal flap, whereas the lowest SpO2 was recorded at the local anesthetic injection. They also concluded that most of the cardiovascular and ventilatory changes induced were within normal ranges.

Rodgers 3 reported the 7-year safety profile of intravenous sedation administered by an oral surgeon. He concluded that less than 3% of the patients experienced complications and no deaths were reported.

Majority of these studies were carried out in developed countries and data on these techniques are scarce from developing countries. Perceived pain, tolerance, anxiety levels, and hemodynamics differ widely among different cultures. Hence, we aimed to compare the hemodynamic parameters among patients who underwent conscious sedation in our institution during the year 2010–2011. Data on the hemodynamic parameters and safety profile were compared between midazolam and propofol administered in combination with fentanyl.

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Materials and methods

A retrospective study was carried out on 55 patients with dental conditions such as third molar impactions, cysts, and implants under local anesthesia and conscious intravenous sedation between May 2010 and April 2011. The data for our study were retrieved from patients’ files in the Medical Records Department by two examiners. Initially, the list of all the individuals who underwent conscious sedation procedures was obtained from the registry. They were then screened and evaluated for their medical history and type of oral surgical procedure. If the individual qualified on the basis of the inclusion criteria, they were further evaluated for the completeness of data of the parameters under study. All the parameters were immediately entered into a proforma developed for the study.

The inclusion criteria were patients with ASA I, II, and III status who underwent local anesthesia and intravenous conscious sedation (propofol/midazolam with fentanyl) for minor oral surgical procedures. Exclusion criteria were patients with incomplete data on the hemodynamic parameters considered for the study. All patients were treated at the Department of Oral and Maxillofacial Surgery, which was equipped with the appropriate sedation and monitoring facilities. Informed consent is obtained routinely for all the patients who undergo any procedure in our department. Permission to carry out the study was obtained from the institutional research committee, Manipal University, Manipal.

The protocol for administration of conscious sedation was as follows: propofol (0.4 mg/kg) and fentanyl (100 μg/kg) and midazolam at 2–8 mg/kg and fentanyl (100 μg/kg) as a bolus injection. Continuous infusion at 1.2 mg/kg/h for propofol and 0.12 mg/kg/h for midazolam was maintained using an infusion pump (Graseby 3160 Syringe Pump; SMS Graseby, Kent, UK). A local anesthetic injection was administered once good sedation was achieved. In all patients, 2% lignocaine hydrochloride with a vasoconstrictor (adrenaline 1 : 200 000) was used. The hemodynamic and ventilatory changes were evaluated by monitoring BP, HR, and SpO2. These values were determined at 12 different time points, that is before commencing surgery (baseline value), during the local anesthetic injection, at the time of incision and raising a mucoperiosteal flap, during the procedure at 5, 10, 15, 20, 25, and 30 min, suturing, and finally at recovery stage as per our protocol for patient management. Intravenous conscious sedation was administered after obtaining the baseline value and before the local anesthetic injection. All the hemodynamic parameters were monitored using a noninvasive BP monitor (Datex Ohmeda S/5; GE Healthcare, Helsinki, Finland).

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Statistical analysis

All the analyses were carried out using SPSS version 17.0 (SPSS Inc., Chicago, Illinois, USA). A P-value of less than 0.05 was considered to be statistically significant. Student’s t-test was used to compare the hemodynamic parameters between the two groups. Repeated-measures analysis of variance was used to evaluate significant differences from baseline to recovery for both the groups independently.

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Results

A total of 55 patients’ records fulfilled our inclusion criteria, among whom only 48 patients had complete data on hemodynamic parameters. Data on HR, mean BP, and SpO2 were compared at 12 intervals between both groups. With respect to the mean HR, no significant difference was observed at baseline, at sedation, and at the local anesthetic injection, whereas significantly higher mean HR was observed in the midazolam+fentanyl group of patients than in the propofol+fentanyl group at time of incision, during the surgery, suturing, and recovery (Table 1).

Table 1
Table 1
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The mean BP was significantly higher for the midazolam+fentanyl group than the propofol +fentanyl group at all the intervals (Table 2). The mean SpO2 was significantly higher for midazolam+fentanyl than propofol+fentanyl at baseline, 20 min during the surgery, and during suturing. At all other intervals, there was no significant difference in the mean SpO2 between both groups (Table 3).

Table 2
Table 2
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Table 3
Table 3
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The mean HR varied with time in the propofol group, whereas no significant difference was observed in the midazolam group (P=0.027 and 0.108), respectively (Table 1). The mean BP varied with time in both groups (P<0.001 and <0.001), respectively (Table 2). The mean SpO2 varied with time in the midazolam group, whereas no significant difference was observed in the propofol group (P=0.033 and 0.177), respectively (Table 3).

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Discussion

We carried out this retrospective study to compare the hemodynamic parameters using propofol and fentanyl. All patients were treated in the same clinical setting, armamentarium, and under the same stringent protocol, but multiple oral surgeons and monitoring assistants were involved in our study. The results of this study must be interpreted with caution considering the inherent limitations of retrospective study.

The thought of undergoing a surgical procedure might induce stress, fear, and anxiety in many individuals, which in turn can lead to elevated hemodynamics. A simple local anesthetic injection can be sufficient to perform majority of minor surgical procedures, but the needle injection may be painful.

Hemodynamic parameters remained stable throughout from baseline till recovery in both groups. Mean BPs were lower in both groups at all the intervals, and the propofol group showed significantly lower mean BP values. This was similar to other studies, which showed that induction of general anesthesia with propofol produced a reduction in systolic and diastolic BP 7,8. Doses of propofol and midazolam adjusted for sedation generally do not produce cardiovascular depression. Fentanyl, which is known to have hypotensive effects (decreases systemic vascular resistance), might have contributed toward the cardiovascular effects 9,10. The differences in HR and BP were not clinically significant, and no special intervention was required.

Compared with the baseline, there was a reduction in the mean BP in both groups. Although this reduction was expected with conscious sedation and the decrease was significant, it has no clinical value. Similar findings were reported by Gold and colleagues 11,12.

Previous reports on the amnestic effects of midazolam have been unrelated to clinical events 13. Amnesia is a common characteristic of benzodiazepines such as midazolam and infusion techniques may prolong its duration 14. Midazolam causes anterograde amnesia, which slowly decreases with time 15. Midazolam is relatively free from side effects on the cardiovascular and respiratory systems at clinical doses. There can be a slight decrease in arterial BP, cardiac output, and peripheral vascular resistance, but there may be an increase in HR. Previous reports indicate that midazolam causes a slight reduction in systolic and diastolic BP and a slight increase in HR, but that these changes are neither statistically significant nor clinically relevant 14.

We found no adverse events from our data. Data on the correct individual dose of the drugs could not be reported because of the retrospective study design. Various factors such as pain, cooperation scores, and psychomotor scores were evaluated in the previous studies and it was found that propofol is a suitable alternative. Our study could not evaluate such factors owing to the retrospective study design. Further, studies considering these factors along with costing issues and other factors need to be carried out for wide applicability and acceptance in developing countries. Considering the limitations of the study, propofol and midazolam appear to be safe and efficacious for intravenous conscious sedation.

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Acknowledgements
Conflicts of interest

There are no conflicts of interest.

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References

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2. Bennett CR.Conscious sedation: an alternative to general anesthesia.J Dent Res1984;63:832–833.

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11. Gold MI, Watkins WD, Sung YF, Yarmush J, Chung F, Uy NT, et al..Remifentanil versus remifentanil/midazolam for ambulatory surgery during monitored anesthesia care.Anesthesiology1997;87:51–57.

12. Esen E, Üstün Y, Balcioǧlu YO, Alparslan ZN.Evaluation of patient-controlled remifentanil application in third molar surgery.J Oral Maxillofac Surg2005;63:457–463.

13. Bell GW, Kelly PJ.A study of anxiety, and midazolam-induced amnesia in patients having lower third molar teeth extracted.Br J Oral Maxillofac Surg2000;38:596–602.

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15. Maranets I, Kain ZN.Preoperative anxiety and intraoperative anesthetic requirements.Anesth Analg1999;89:1346–1351.

© 2014 Egyptian Associations of Oral and Maxillofacial Surgery

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