Editorial Type: Departments
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Online Publication Date: 01 Jan 2008

JSDA Abstracts

Article Category: Meeting Report
Page Range: 134 – 138
DOI: 10.2344/0003-3006-55.4.134
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Balance Anesthesia Using Sevoflurane and Fentanyl Based on Site Concentration Model Compared to Sevoflurane/N2O Anesthesia for Oral Surgery

Kanta Kido, Atsuko Aoi, Toshihiro Konno, Makoto Yasuda, Minoru Sato, Hajime Shimoda, Toshiro Igari and Masahiko Takahashi, Division of Anesthesia and Pain Management, Tohoku University Hospital (Chief: Prof. Masahiko TAKAHASHI)

The use of opioids in general anesthesia is a key component in the current notion of “balanced anesthesia”. However, concern over opioid side effects can cause practitioners to hesitate to use opioids. Fentanyl is a commonly used opioid in perioperative management, because it allows smooth emergence from anesthesia without coughing and bucking, and provides residual postoperative analgesia. In this study, the adverse symptoms of “balanced anesthesia” using fentanyl and sevoflurane based on site concentration model was compared to those of “traditional anesthesia” using nitrous oxide (N2O) during oral surgery.

Forty patients scheduled to undergo oral surgery (ASA classification 1 or 2) were assigned randomly into one of two groups that were maintained with anesthesia using fentanyl and sevoflurane (group AOS/F, n  =  20) and the second group using N2O and sevoflurane (group GOS, n  =  20). Fentanyl was administered intermittently to maintain the effect-site concentration at 2–3 ng/ml using a pharmacokinetic simulation software in the group AOS/F. The time to awake (from the end of surgery to extubation) and the frequency in using an antiemetic drug (metoclopramide hydrochloride) during 24 hours postoperatively were compared between the two groups. At the end of anesthesia, the total dose of fentanyl used and the respiratory rate data were evaluated.

There were no significant differences in the time to awake and the use of postoperative antiemetic drug between the two groups (Table 2). In AOS/F group, the total dose of fentanyl was 386 ± 31.5 µg and the respiratory rate was 13.2 ± 0.6 breaths/min at the end of anesthesia.

The results indicated that the use of fentanyl based on this pharmacokinetic model did not increase the adverse symptoms known to be related to opioids after general anesthesia, and suggested that fentanyl-based balanced anesthesia could be as safe as traditional GOS anesthesia.

Table 1 Patient Demographic Data
Table 1
Table 2 Incidence of Side Effect
Table 2

Airway Management during Dental Implant Surgery with Intravenous Sedation for Obstructive Sleep Apnea Syndrome and Use of Continuous Positive Airway Pressure

Shigeru Tatebayashi, Takao Okada, Yuichiro Imai*, and Tadaaki Kirita*, Osaka Implant Center (Chief: Takao OKADA) and *Department of Oral and Maxillofacial Surgery, Nara Medical University (Chief: Prof. Tadaaki KIRITA)

Sleep Apnea Syndrome (SAS) is a critical disease which causes complications such as hypertension, cardiac disease and apoplexy. It is estimated that over 70,000 patients have received the continuous positive airway pressure (CPAP) treatment. As the number of dental implants increases, it is believed that the incidence to treat patients with SAS will become more frequent in the near future. There have been very few reports on airway management in oral surgery, especially during dental implant surgery with intravenous sedation (IVS) for SAS including Obstructive Sleep Apnea Syndrome (OSAS).

We applied CPAP in OSAS as an airway management method during dental implant surgery with IVS, and investigated the efficacy and safety. Three outpatients diagnosed with OSAS confirmed by Polysomnography were selected for this study, and all had dental implant surgery at Osaka Implant Center. Case 1: 42 years old male. CPAP treatment was started one month ago for OSAS due to obesity. However, compliance with CPAP was low, so dental implant surgery was performed under IVS with O2 administered by nasal cannula. Case 2: 54 years old male. CPAP treatment had been continued for two years and there were no issues with compliance, so dental implant surgery was performed using CPAP with IVS as intra-operative airway management. Case 3: 60 years old male. CPAP treatment had been continued for a year and six months. Because there was no problem in his CPAP compliance, CPAP was applied during operation with IVS.

Changes and end-points: blood pressure, heart rate, Spo2, Ramsay Sedation Score (RSS: used as an index of sedation depth); In Case 1, hypertension and tachycardia were found since the patient entered the operating room, and continued during IVS (Fig. 1, 2). We administered randiolol (total 25 mg) to decrease the heart rate. When sedation depth was set to nearly 3 by RSS, the upper airway was obstructed, and Spo2 fell rapidly to 80%. On the other hand, with CPAP the blood pressure and heart rate were stable and the upper airway obstruction was not seen even when the level of sedation exceeded RSS 4 (Fig. 4, 5, 8 and 9). Postoperative interviews with the patients showed that amnesia was also fully attained.

In conclusion, compared with oxygenation by nasal cannula, the two cases who used CPAP were oxygenated sufficiently and maintained stable, even during deep sedation with air breathing. Although the cases presented here are limited to OSAS patients who have had used CPAP prior to the procedure, the results in this study suggest that CPAP may be an effective, safe method for airway management during dental implant surgery with IVS.

Figure 1. Changes in blood pressure and heart rate in case 1.Figure 1. Changes in blood pressure and heart rate in case 1.Figure 1. Changes in blood pressure and heart rate in case 1.
Figure 1 Changes in blood pressure and heart rate in case 1.

Citation: Anesthesia Progress 55, 4; 10.2344/0003-3006-55.4.134

Figure 2. Changes in Spo2 and Ramsay Sedation Score in case 1.Figure 2. Changes in Spo2 and Ramsay Sedation Score in case 1.Figure 2. Changes in Spo2 and Ramsay Sedation Score in case 1.
Figure 2 Changes in Spo2 and Ramsay Sedation Score in case 1.

Citation: Anesthesia Progress 55, 4; 10.2344/0003-3006-55.4.134

Figure 3. CPAP device applied to case 2 and 3 (GoodNight 420E: PURITAN BENNETT, USA).Figure 3. CPAP device applied to case 2 and 3 (GoodNight 420E: PURITAN BENNETT, USA).Figure 3. CPAP device applied to case 2 and 3 (GoodNight 420E: PURITAN BENNETT, USA).
Figure 3 CPAP device applied to case 2 and 3 (GoodNight 420E: PURITAN BENNETT, USA).

Citation: Anesthesia Progress 55, 4; 10.2344/0003-3006-55.4.134

Figure 4. Changes in blood pressure and heart rate in case 2 Both blood pressure and tachycardia were stable.Figure 4. Changes in blood pressure and heart rate in case 2 Both blood pressure and tachycardia were stable.Figure 4. Changes in blood pressure and heart rate in case 2 Both blood pressure and tachycardia were stable.
Figure 4 Changes in blood pressure and heart rate in case 2 Both blood pressure and tachycardia were stable.

Citation: Anesthesia Progress 55, 4; 10.2344/0003-3006-55.4.134

Figure 5. Changes in Spo2 and Ramsay Sedation Score in case 2.Figure 5. Changes in Spo2 and Ramsay Sedation Score in case 2.Figure 5. Changes in Spo2 and Ramsay Sedation Score in case 2.
Figure 5. Changes in Spo2 and Ramsay Sedation Score in case 2.

Citation: Anesthesia Progress 55, 4; 10.2344/0003-3006-55.4.134

Figure 6. Photograph after having attached CPAP to a patient.Figure 6. Photograph after having attached CPAP to a patient.Figure 6. Photograph after having attached CPAP to a patient.
Figure 6 Photograph after having attached CPAP to a patient.

Citation: Anesthesia Progress 55, 4; 10.2344/0003-3006-55.4.134

Figure 7. Photograph after having surrounded drape to a patient. The rise about 5 cm has been made in the mid-face of patient due to nasal mask of CPAP.Figure 7. Photograph after having surrounded drape to a patient. The rise about 5 cm has been made in the mid-face of patient due to nasal mask of CPAP.Figure 7. Photograph after having surrounded drape to a patient. The rise about 5 cm has been made in the mid-face of patient due to nasal mask of CPAP.
Figure 7 Photograph after having surrounded drape to a patient. The rise about 5 cm has been made in the mid-face of patient due to nasal mask of CPAP.

Citation: Anesthesia Progress 55, 4; 10.2344/0003-3006-55.4.134

Figure 8. Changes in blood pressure and heart rate of case 3.Figure 8. Changes in blood pressure and heart rate of case 3.Figure 8. Changes in blood pressure and heart rate of case 3.
Figure 8 Changes in blood pressure and heart rate of case 3.

Citation: Anesthesia Progress 55, 4; 10.2344/0003-3006-55.4.134

Figure 9. Changes in Spo2 and Ramsay Sedation Score in case 3.Figure 9. Changes in Spo2 and Ramsay Sedation Score in case 3.Figure 9. Changes in Spo2 and Ramsay Sedation Score in case 3.
Figure 9 Changes in Spo2 and Ramsay Sedation Score in case 3.

Citation: Anesthesia Progress 55, 4; 10.2344/0003-3006-55.4.134

Respiratory Depression during Sedation with Remifentanil and Propofol

Yoshino Imai, Masahiro Yamada, Makiko Kawaguchi, Masayo Matsuura and Jun Harada, Department of Anesthesiology, School of Dentistry, Aichi-Gakuin University (Chief: Prof.Jun HARADA)

Introduction: Respiratory management during sedation in oral surgery is important because the operative field is in the airway area. We investigated respiratory depression during sedation at various infusion rates of remifentanil combined with propofol in similar levels of sedative state.

Subjects and methods: Forty-five patients undergoing oral surgery were randomly divided into three groups: Remifentanil 0.03 µg/kg/min was infused in group A, 0.07 µg/kg/min in group B, and 0.1 µg/kg/min in group C from induction of anesthesia to the end of surgery. In addition, propofol was administered continuously at sedation level “3” in OAA/S Sedation Scale in the three groups. Respiratory rate, Petco2 at the nasal cavity, heart rate and blood pressure were recorded during remifentanil infusion. The maximum and minimum values were compared with those of preinduction values. In addition, the incidences of apnea, bradypnea, movement of extremities and coughing were compared among the three groups. Apnea was defined as respiratory arrest for 15 seconds or more and bradypnea as 8 breaths/min or less of respiratory rate. Data are presented as median (maximum; minimum) and number of patients.

Results: Minimum effect site concentration of propofol (µg/ml) was 1.6 (2.4; 1.0) in group A, 1.2 (2.0; 0.8) in group B and 0.8 (1.5; 0.2) in group C. Therefore, propofol requirements decreased significantly as the infusion rate of remifentanil increased (p  =  0.0001) (Table 2). The respiratory rate decreased significantly as the infusion rate of remifentanil increased (p  =  0.0002), and in comparison with preinduction values, it was significantly decreased in the three groups (p  =  0.0012, 0.0008 and 0.0008, respectively). Petco2 significantly increased intraoperatively in all three groups (p  =  0.0009, 0.0007 and 0.0007, respectively) and with the infusion rate of remifentanil (p  =  0.0010). The number of patients with hypoventilation where Petco2 increased to 50 mmHg or more was as follows: 8 cases in group A, 13 in group B and 14 in group C (p  =  0.0186) (Table 3). Apnea was observed in 3 patients in group A, 10 in group B and 11 in group C, and bradypnea was observed in one, 10 and 10, in groups A, B, and C, respectively. The incidence of apnea and bradypnea in group B and C was significantly higher (p  =  0.0062 and 0.0007, respectively) (Table 5).

Conclusions: We demonstrated that the respiratory depression became more marked as the infusion rate of remifentanil increased. Therefore, the infusion rate of remifentanil should be kept at 0.03 µg/kg/min or less during sedation using remifentanil and propofol. It is important that sedation in oral surgery is maintained at sedation level “3” in OAA/S Sedation Scale and that the patients can take deep breaths promptly and sufficiently in response to verbal commands.

Table 1 Patient Characteristics in Three Groups
Table 1
Table 2 Comparison of Maximum and Minimum Propofol Effect Site Concentration to be Required at OAA/S Sedation Scale “3”
Table 2
Table 3 Respiratory Depression Caused by Administration of Remifentanil and Propofol at OAA/S Sedation Scale “3”
Table 3
Table 4 Circulatory Depression Caused by Administration of Remifentanil and Propofol at OAA/S Sedation Scale “3”
Table 4
Table 5 Incidence of Apnea, Bradypnea, Movement of Extremities and Cough Caused by Administration of Remifentanil and Propofol
Table 5
Copyright: 2008 by the American Dental Society of Anesthesiology 2008
Figure 1
Figure 1

Changes in blood pressure and heart rate in case 1.

Figure 2
Figure 2

Changes in Spo2 and Ramsay Sedation Score in case 1.

Figure 3
Figure 3

CPAP device applied to case 2 and 3 (GoodNight 420E: PURITAN BENNETT, USA).

Figure 4
Figure 4

Changes in blood pressure and heart rate in case 2 Both blood pressure and tachycardia were stable.

Figure 5.
Figure 5.

Changes in Spo2 and Ramsay Sedation Score in case 2.

Figure 6
Figure 6

Photograph after having attached CPAP to a patient.

Figure 7
Figure 7

Photograph after having surrounded drape to a patient. The rise about 5 cm has been made in the mid-face of patient due to nasal mask of CPAP.

Figure 8
Figure 8

Changes in blood pressure and heart rate of case 3.

Figure 9
Figure 9

Changes in Spo2 and Ramsay Sedation Score in case 3.

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