Chizuko Yokoe

A Prospective, Randomized Controlled Trial of Conscious Sedation Using Propofol Combined With Inhaled Nitrous Oxide for Dental Treatment

PURPOSE Adverse reactions during propofol sedation include a decrease in arterial blood pressure, propofol-induced pain on injection, and airway complications. The purpose of this study was to investigate whether combined use of intravenous propofol and inhaled nitrous oxide could decrease the hypotensive and other adverse effects of propofol. PATIENTS AND METHODS We designed and implemented a prospective, randomized controlled trial. Patients undergoing dental procedures requiring intravenous sedation were randomly allocated to 2 groups: group P comprised those receiving sedation with propofol alone, and group N+P comprised those receiving sedation with 40% nitrous oxide inhalation and propofol. During the dental procedures, the sedation level was maintained at an Observers Assessment of Alertness/Sedation scale score of 4 by adjusting propofols target plasma concentration. Nitrous oxide inhalation was the predictor variable, whereas the hemodynamic changes, amount and concentration of propofol, and adverse events were the outcome variables. RESULTS Eighty-eight patients were successfully analyzed without any complications. The total amount of propofol was significantly less in group N+P (249.8 ± 121.7 mg) than in group P (310.3 ± 122.4 mg) (P = .022), and the mean concentration of propofol was significantly less in group N+P (1.81 ± 0.34 μg/mL) than in group P (2.05 ± 0.44 μg/mL) (P = .006). The mean blood pressure reduction in group N+P (11.0 ± 8.0 mm Hg) was significantly smaller than that in group P (15.8 ± 10.2 mm Hg) (P = .034). Pain associated with the propofol injection and memory of the procedure were less in group N+P (P = .011 and P = .048, respectively). Nitrous oxide did not affect respiratory conditions or recovery characteristics. CONCLUSIONS The results of this study suggest that nitrous oxide inhalation combined with propofol sedation attenuates the hypotensive effect and pain associated with propofol injections, along with potentiating the amnesic effect.

The effect of nitrous oxide inhalation on the hypotensive response to propofol: a randomized controlled trial

OBJECTIVE Decrease in arterial blood pressure is a prominent adverse reaction during propofol (Disoprivan; AstraZeneca K.K., Osaka, Japan) sedation. The purpose of this prospective randomized study was to explore the effects of nitrous oxide (N2O) on the hypotensive response during propofol sedation. STUDY DESIGN Twenty-six healthy volunteers received intravenous sedation with propofol alone (group P, n=13) or a combined technique using 20% N2O and propofol (group N+P, n=13). Propofol was administered by a target-controlled infusion system to attain and maintain a plasma propofol concentration of 1.5μg/mL. Hemodynamic and autonomic parameters were measured. RESULTS Mean arterial pressure decreased in both groups, the hypotensive response in group N+P being significantly smaller than in group P. Reduction in the low-frequency power of systolic blood pressure variability, indicative of sympathetic nervous activity, was also smaller in group N+P than in group P. CONCLUSIONS Addition of N2O to propofol sedation can attenuate the hypotensive effect of propofol.

Tooth extraction in patients taking nonvitamin K antagonist oral anticoagulants

Background/purpose The nonvitamin K antagonist oral anticoagulants direct-thrombin inhibitor dabigatran and the Xa inhibitors rivaroxaban and apixaban are now being used clinically. The course of the patients on these anticoagulants who underwent tooth extraction was assessed. Materials and methods The medical charts of these patients were investigated. Tooth extraction was performed while maintaining conventional anticoagulant therapy. Results Twenty-three teeth were extracted in 19 patients, including two surgical extractions. Among the 19 patients, nine patients ingested rivaroxaban, six apixaban, and four dabigatran. One patient on rivaroxaban showed persistent postoperative bleeding following two surgical extractions. Mild oozing was observed in five patients (two on rivaroxaban and three on apixaban). There was no bleeding episode in the patients on dabigatran. Conclusion The patients on rivaroxaban with a prolonged prothrombin time value have a higher risk of bleeding, especially undergoing surgical extraction. Apixaban correlates to neither activated partial thromboplastin time nor prothrombin time values and the countermeasures should be employed based on the clinical findings.

Haemostatic management for oral surgery in patients supported with left ventricular assist device– a preliminary retrospective study

We investigated haemostatic management, frequency of postoperative bleeding, and prognosis of patients who had left ventricular assist devices, and who were having oral surgical procedures between April 2002 and March 2014, to identify risk factors for bleeding and find out which were the best methods of haemostasis. Medical records were examined retrospectively and we recorded details of the patients, and frequency of bleeding together with factors associated with it. Twenty-nine patients had 39 oral operations, and there were 17 bleeds (44%). The first procedure for each patient was used for statistical calculations. Duration of bleeding tended to be longer for patients with implantable devices (median (interquartile range, IQR) 12.0 (3-18) days) than for those with extracorporeal devices (median (IQR) 3.0 (1-4) days; p=0.079). There was a significantly greater difference in prothrombin time-international normalised ratio (PT-INR) before and after operation in patients who bled, whose median (range) was 0.85 (0.2-1.81), than in those who did not (median (IQR) 0.16 (-0.09-0.31) (p=0.015). There were moderate correlations with postoperative bleeding were seen for the difference between preoperative and postoperative PT-INR (r=0.479, p=0.012) and PT-INR value when bleeding (r=0.407, p=0.035). In conclusion, postoperative bleeding occurred after oral operations in 17/29 patients with left ventricular assist devices by a median (IQR) of 0.85 (0.2-1.81) of the preoperative value.

Arteriosclerosis can predict hypotension during anesthesia induction in patients 40 years and older

STUDY OBJECTIVES To identify the factors that predict blood pressure (BP) changes during induction of general anesthesia, and the relationship between the level of arteriosclerosis and BP changes during anesthesia induction. DESIGN Prospective, case-control observational study. SETTINGS Operating room of a university hospital. PATIENTS Seventy-two patients who received general anesthesia for oral and maxillofacial surgery. MEASUREMENTS Brachial-ankle pulse wave velocity (baPWV) and central BP were measured. The primary variable was the parameters affecting BP changes during the induction of general anesthesia. For additional analyses, the parameters were compared between high and low PWV groups (1606 cm/s was the cutoff value of baPWV). To measure the relationships between the parameters and BP changes, bivariate and multiple linear regression analyses were performed. RESULTS Seventy-two patients (including 41 men) with a mean age of 61.7 years and a median baPWV value of 1606 cm/s were evaluated. Significantly higher values for age, central BP, preoperative systolic BP (SBP), amount of decrease in SBP and diastolic BP, and number of patients with diabetes mellitus (DM) and hypertension were observed in the high PWV group. Multiple linear regression analysis demonstrated that age, baPWV, and DM were factors independently associated with the amount of decrease in SBP. CONCLUSION In patients 40 years and older, age, baPWV, and DM are thought to be effective predictors of the amount of decrease in SBP during induction of general anesthesia.

Airway management for glossopexy in infants with micrognathia and obstructive breathing

STUDY OBJECTIVES To identify airway management and tracheal intubation techniques for glossopexy in infants with preexisting airway obstruction under general anesthesia. DESIGN Retrospective, observational study. SETTINGS Operating room of a university hospital between January 2003 and March 2015. All operations were performed by oral and maxillofacial surgeons. PATIENTS Thirteen patients who received general anesthesia for glossopexy and reversal after 7 months. MEASUREMENTS The medical records of these infants were retrospectively examined to evaluate the following: age, sex, height and weight at surgery, preoperative airway status, tracheal intubation route (oral or nasal), method for inducing general anesthesia, method for establishing the airway during mask ventilation, apparatus used for tracheal intubation, Cormack-Lehane classification when using a Macintosh laryngoscope and video laryngoscope, and the need for airway placement after extubation. RESULTS Prone positioning and/or an airway of some kind before surgery were required in 38.5% of infants needing glossopexy. Difficult mask ventilation was common, occurring in 50% of the patients, and the incidence of airway placement during mask ventilation was significantly higher in infants with preoperative complete or incomplete obstruction (100%) than in infants with snoring (25%). Of these high-risk infants, 25% could not be intubated with a direct laryngoscope or Glidescope Cobalt and required fiberoptic intubation. CONCLUSION There are severe cases of infants with difficult mask ventilation and difficult tracheal intubation in which a fiberscope is required because video laryngoscopy fails to improve the view of the larynx.