Hemodynamics and Oxygen Saturation During Intravenous Sedation for office-based Laser-Assisted Uvuloplasty

J Oral Maxillofac Surg 63:752-755, 2005

Hemodynamics and Oxygen Saturation During Intravenous Sedation for Office-Based Laser-Assisted Uvuloplasty Joseph E. Cillo, Jr, DMD,* and Richard Finn, DDS† Purpose: Patients undergoing office-based laser-assisted uvuloplasty (LAUP) for snoring or mild ob-

structive sleep apnea are generally obese and have a high Mallampati score. Because avoidance of supplemental oxygen during laser procedures is generally mandated, the potential for intraoperative desaturation is high. This study was designed to look at intraoperative hemodynamic changes, respiration patterns, and oxygen saturations during intravenous sedation with midazolam and fentanyl during LAUP procedures. Materials and Methods: This was a retrospective anesthesia chart review of 15 consecutive patients undergoing midazolam/fentanyl intravenous sedation for office-based LAUP treatment for snoring and/or mild obstructive sleep apnea. Data recorded were noninvasive baseline and intraoperative hemodynamic measurements at 5-minute intervals for systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse pressure (PP), pulse (P), and rate-pressure product (RPP). Data collected were reported as mean values with standard deviation. Statistical analysis using the Student’s t test was performed and found significant for P ⬍.05. Results: All changes from baseline were statistically insignificant, SBP (P ⫽ .4), DBP (P ⫽ .2), MAP (P ⫽ .2), P (P ⫽ .1), PP (P ⫽ .9), RPP (P ⫽ .5), RR (P ⫽ .9), and SpO2 (P ⫽ .4), and all within ⫾20% of baseline (range, ⫺5.0% to ⫹7.5%). Conclusion: Midazolam and fentanyl intravenous sedation with local anesthesia maintained intraoperative hemodynamic and oxygenation variables close to baseline for office-based LAUP procedures. © 2005 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 63:752-755, 2005 mild OSA.8,9 Patients with high Mallampati scores, a scale used, in part, to determine the length of the base of uvula,10 have increased incidences of habitual snoring and OSA.11,12 Laser-assisted uvuloplasty (LAUP) has been a proven technique to reduce or eliminate snoring and/or mild OSA.13-19 Office-based surgery has become commonplace as a method to provide health care at reduced cost with efficiency and safety.20,21 Office-based LAUP generally prohibits the use of supplemental oxygen during surgery because of the fire hazard,22,23 thereby increasing the probability of intraoperative desaturation and possible resulting hemodynamic exacerbations.24-26 In addition, because snoring and OSA are associated with obesity and cardiovascular diseases,1-4,27 including a correlation with increased prevalence for unrecognized left ventricular dysfunction,28 careful monitoring of intraoperative hemodynamics is essential to prevent acute and prolonged exacerbations. The purpose of this study was to retrospectively examine the effect of the office-based LAUP procedure using midazolam and fentanyl intravenous (IV) sedation on intraoperative hemodynamic and oxygen readings compared with baseline.

Habitual snoring and mild obstructive sleep apnea (OSA) have been shown to be closely associated with increased incidences of cardiovascular diseases such as hypertension,1,2 coronary artery disease,3 and myocardial infarction.4 In addition, habitual snoring and mild OSA lead to excessive daytime sleepiness that has been shown to increase the likelihood of occupational accidents.5-7 An estimated 24% of men and 9% of women aged 30-60 years have habitual snoring or

*Chief Resident, Oral and Maxillofacial Surgery, Parkland Memorial Hospital, The University of Texas Southwestern Medical Center, Dallas, TX. †Professor, Department of Surgery, Division of Oral and Maxillofacial Surgery and Department of Cell Biology, The University of Texas Southwestern Medical Center, Dallas, TX; Chief, Oral and Maxillofacial Surgery, Veterans Administration North Texas Health Care System, Dallas, TX. Address correspondence and reprint requests to Dr Cillo: 2612 Catalina Way, Irving, TX 75060. © 2005 American Association of Oral and Maxillofacial Surgeons

0278-2391/05/6306-0006$30.00/0 doi:10.1016/j.joms.2005.02.004

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CILLO AND FINN

Table 1. AVERAGE AND BASELINE CHANGES FOR HEMODYNAMICS AND OXYGENATION

BL Avg. (SD) Intraoperative Avg. (SD) Change (⌬%) P Value

SBP (mmHg)

DBP (mmHg)

MAP (mmHg)

P (bpm)

PP (mmHg)

RPP (bpm ⫻ SBP)

RR (bpm)

SpO2 (%)

136.9 (18.0) 131.6 (20.3) ⫺3.8 .4

80.6 (12.6) 76.6 (13.5) ⫺5.0 .2

93.4 (13.0) 94.9 (13.9) ⫺4.5 .2

69.9 (10.1) 75.0 (13.6) ⫹7.5 .1

56.2 (14.0) 55.2 (17.3) ⫺2.0 .9

9,547.4 (1,738.6) 9,947.3 (2,507.7) ⫹3.9 .5

15.7 (1.7) 15.5 (1.4) ⫹1.1 .9

95.9 (3.0) 95.2 (3.1) ⫺0.7 .4

Abbreviations: BL, baseline reading; SBP, systolic blood pressure; DBP, diastolic blood pressure; P, pulse; PP, pulse pressure; RPP, rate pressure product; RR, respiratory rate; SpO2, oxygen saturation; bpm, beats per minute. Cillo and Finn. Hemodynamics & SPO2 During IV Sedation for LAUP. J Oral Maxillofac Surg 2005.

Materials and Methods This was a retrospective chart review of 15 consecutive patients undergoing midazolam/fentanyl IV sedation-analgesia for office-based LAUP. All procedures and anesthetics were performed between January 1998 and October 2002 at the same Oral and Maxillofacial Surgery Outpatient Clinic. Patients were referred to the Oral and Maxillofacial Surgery Department for surgical evaluation following polysomnography-confirmed snoring and/or mild OSA. Patients were given treatment options and chose to have the LAUP procedure performed under IV sedation-analgesia. Continuous electrocardiogram, noninvasive blood pressure, pulse oxymetry monitors were placed and 1-time baseline preoperative measurements taken to include systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse (P), respiratory rate (RR), and oxygen saturation (SpO2). Respiration rate was determined by visualization of patient chest wall movements by the anesthesia assistant. Following placement of a peripheral IV catheter, all patients received IV methyprednisone 125 mg, cefazolin 2 g, fentanyl 50 to 100 mcg, and midazolam 1 to 5 mg. Patients were sedated to a level sufficient to allow administration of local anesthetic. All patients received bilateral cranial nerve V-2 nerve blocks via the greater palatine canal with a minimum of 3.6 cc of 2% lidocaine with 1:100,000 epinephrine as previously described.14 While awaiting the onset of anesthesia, the supplemental oxygen was removed and the patient allowed to breathe room air. Following onset of profound cranial nerve V-2 anesthesia, the LAUP procedure was completed using the Sharplan Model 20C (Sharplan Lasers Ltd, London, England) with LAUP backstop handpiece at 7.5 watts of superpulse energy as previously described.14 Intraoperative data were recorded at 5-minute intervals for SBP, DBP, MAP, P, RR, and SpO2. Measurements for pulse pressure (PP) and rate pressure product (RPP) were calculated at a later time using published calculations.31 Additional IV anesthesia was

titrated if necessary for patient comfort. Patients were recovered in the same procedure room; discharge criteria were based on the Aldrete Post Anesthesia Recovery Scores (APARS: 0 to 10). Data collected were averaged over the entire course of the procedure because specific reading for specific stages of the surgery were not available. Data collected were reported as mean values with standard deviation. Statistical analyses between groups were performed using the Microsoft Excel (Microsoft Corp, Redmond, WA) program using the Student’s t test and found statistically significant for P ⬍.05.

Results A total of 15 consecutive white male patients, ASA physical status II-III, not actively taking beta-blockers, and all having Mallampati III scores undergoing LAUP procedure with IV sedation-analgesia for treatment of polysomnography-confirmed snoring and/or mild OSA were involved in this study. All changes from baseline (Table 1) were statistically insignificant, SBP (⫺3.8%; P ⫽ .4), DBP (⫺5.0%; P ⫽ .2), MAP (⫺4.5%; P ⫽ .2), P (⫹7.5%; P ⫽ .1), PP (⫺2.0%; P ⫽ .9), RPP (⫹3.9%; P ⫽ .5), RR (⫹1.1%; P ⫽ .9), and SpO2 (⫺0.7%; P ⫽ .4), and were within ⫾20% of baseline (range, ⫺5.0% to ⫹7.5%). Average length of procedure was 30.4 minutes ⫾ 12.9 minutes (Table 2). Average amount of midazolam administered was 3.4 mg ⫾ 1.2 mg and fentanyl was 82.1 mcg ⫾ 42.1 mcg (Table 2). SpO2 levels were maintained above 90% on room air in all patients. No patient required supplemental perioperative oxygen following administration of local anesthetic, and no patient developed airway obstruction or significant respiratory distress during the procedures. All patients were awake and oriented with an APAR score of 10 at the time of discharge. Instances of postoperative nausea and vomiting were not recorded.

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HEMODYNAMICS & SPO2 DURING IV SEDATION FOR LAUP

Table 2. ANESTHETICS ADMINISTERED AND TIME OF PROCEDURE

Average ⫾ SD

Midazolam

Fentanyl

Time

3.4 mg ⫾ 1.2

82.1 mcg ⫾ 42.1

30.4 min. ⫾ 12.9

Cillo and Finn. Hemodynamics & SPO2 During IV Sedation for LAUP. J Oral Maxillofac Surg 2005.

Discussion The incidence of snoring and mild OSA is common8,9 and is associated with many morbidities.1-7 The LAUP is a short and effective procedure for the treatment of snoring and mild OSA.13-19 Because of its low level of morbidity and short duration, LAUP is amenable to the office-based setting.29 Office-based surgery has had increased utilization in the past 2 decades because of improved anesthetic techniques and appropriate selection of procedures and patients.30-32 The LAUP procedure has been performed under both local anesthesia alone13,29 or combined with IV sedation.14 The standard of care during IV sedation is for supplemental oxygen to be delivered during the procedure.33 However, because of safety issues, the use of supplemental oxygen in the LAUP procedure is generally contraindicated.22,23 Because patients undergoing this procedure already had polysomnogram-diagnosed snoring and/or mild OSA and tended to have a small upper airway, as expressed by high Mallampati scores, the possibility of desaturation was increased.34,35 Additionally, administration of IV opioids, such as fentanyl, are known to produce respiratory depression,36 and, especially when combined with an IV benzodiazepine such as midazolam, can increase the occurrence of transient episodes of respiratory depression and oxygen desaturation.37 Anesthesia used in office-based procedures has been shown to be safe and effective.38-42 However, patients with diagnosed snoring and mild OSA must be monitored closely to prevent desaturation and any resulting prolonged hemodynamic changes. The high association of snoring and mild OSA with cardiovascular diseases1-4 and undiagnosed left ventricular dysfunction28 may increase the potential for intraoperative myocardial ischemia. The results of this study have shown that, despite the lack of supplemental intraoperative oxygen and high Mallampati score, the short duration of the average LAUP procedure (30.4 min ⫾ 12.9) coupled with midazolam and fentanyl sedation-analgesia maintained intraoperative hemodynamic and oxygenation values close to baseline, remaining within a ⫾20% range (range, ⫺5.0% to ⫹7.5%) as recommended by several anesthesia authorities.43-45 In conclusion, IV midazolam and fentanyl sedation for office-based LAUP allowed for adequate oxygenation and maintained a stable hemodynamic state

close to the patient’s baseline. This investigation does have the unfavorable design qualities inherent in retrospective studies and a limited number of patients. A prospective randomized study with a greater number of patients and measurements taken at specific intervals in the procedure (eg, local anesthesia administration, start of procedure) would be beneficial.

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