Dexmedetomidine reduces sevoflurane EC₅₀ for supraglottic airway device insertion in spontaneously breathing morbidly obese patients

Figures & data

Figure 1 Flow diagram of morbidly obese patients’ recruitment.

Notes: Group S, saline was given intravenously; group D, a bolus dose of DEX 1 μg/kg was administered intravenously over 10 mins, followed by intravenous DEX infusion at a rate of 0.5 μg/kg/h.

Table 1 Demographic data

	Group S	Group D
	n=16	n=22
Age (yrs)	30.2±4.7	30.4±6.1
Sex (M:F)	5/11	6/16
BMI (kg/m^2)	45.2±5.6	44.3±4.0
Interincisor distance (cm)	7.1±1.5	6.6±0.6
Thyromental distance (cm)	8.8±1.1	8.4±0.9
Neck circumference (cm)	46.9±4.0	46.3±4.4
Mallampati class
II	8	12
III	7	8
IV	1	2
Hypertension	4	7
Diabetes mellitus	8	13
Hyperlipaemia	9	10

Notes: Group S, saline was given intravenously; group D, a bolus dose of DEX 1 μg/kg was administered intravenously over 10 mins, followed by intravenous DEX infusion at a rate of 0.5 μg/kg/h.

Abbreviations: BMI, body mass index; D, dexmedetomidine; S, saline.

Figure 2 Responses of morbidly obese patients in the two groups with the modified Dixon’s up-and-down method. Responses of 16 (group S) and 22 (group D) consecutive morbidly obese patients to BlockBuster^TM SAD insertion and their ET_sev with a modified Dixon’s up-and-down method are shown. Arrows indicate the mid-point dose of all independent pairs of patients who manifested cross-over from “movement” (○) to “no movement” (●) response.

Abbreviations: D, dexmedetomidine; S, saline; SAD, supraglottic airway device.

Notes: Group S, saline was given intravenously; group D, a bolus dose of DEX 1 μg/kg was administered intravenously over 10 mins, followed by intravenous DEX infusion at a rate of 0.5 μg/kg/h.

Figure 3 Dose–response curves of sevoflurane for successful insertion of BlockBuster^TM SAD in the two groups. The curves plotted from probit regression analysis of individual ET_sev and the responses to BlockBuster^TM SAD insertion in the morbidly obese patients were shown.

Notes: Group S, saline was given intravenously; group D, a bolus dose of DEX 1 μg/kg was administered intravenously over 10 mins, followed by intravenous DEX infusion at a rate of 0.5 μg/kg/h.

Abbreviations: D, dexmedetomidine; S, saline; SAD, supraglottic airway device.

Table 2 Adverse events related to anesthetic induction and SAD insertion

	Group S	Group D
	n=16	n=22
Anesthetic induction period
Excitatory movements	2	3
Coughing	1	1
Apnea	4	3
Hypotension	3	2
Bradycardia	1	1
SADs insertion period
Muzi score>2	2	4
Purposeful limb movement	2	6
Coughing	3	5
Breath holding	2	4

Notes: Group S, saline was given intravenously; group D, abolus dose of DEX 1 μg/kg was administered intravenously over 10 mins, followed by intravenous DEX infusion at a rate of 0.5 μg/kg/h.

Abbreviations: D, dexmedetomidine; S, saline; SAD, supraglottic airway device.