Minimum Alveolar Concentration-Awake of Sevoflurane is Decreased in Patients with Parkinson’s Disease: An Up-and-Down Sequential Allocation Trial

Figures & data

Table 1 Patients’ Characteristics and Arterial Blood Gas Results

Parameters	PD Group (n=20)	NPD Group (n=21)	P
Age, yr	57.2±6.7	54.8±6.0	0.236
Sex, male/female	9/11	10/11	0.867
Height, cm	161.8±8.0	163.4±5.8	0.463
Weight, kg	60.1±6.9	62.8±6.9	0.215
Temperature, °C	36.4±0.2	36.4±0.2	0.600
pH	7.41±0.03	7.41±0.02	0.577
PaO2 (mmHg)	85.2±4.2	86.6±3.3	0.216
PaCO2 (mmHg)	37.7±1.5	37.8±2.6	0.882
Na^+ (mmol/L)	139.7±2.5	138.2±1.7	0.033*
K^+ (mmol/L)	3.9±0.4	3.8±0.2	0.285
Ca^2+ (mmol/L)	1.10±0.03	1.09±0.03	0.512
Glucose (mmol/L)	5.5±0.6	5.8±0.5	0.081
Lactic acid (mmol/L)	1.55±0.26	1.60±0.31	0.474
Hemoglobin (g/L)	119.3±11.0	117.7±10.7	0.643
Hematocrit (%)	0.35±0.03	0.34±0.03	0.373

Notes: Data are presented as mean ± S.D. or number of subjects. *The P value for significance tested by t test is set at < 0.05.

Abbreviations: PD, Parkinson’s disease; NPD, non-Parkinson’s disease.

Table 2 The Anti-Parkinson Medications Taken by Patients with Parkinson’s Disease

Medications	Number of Uses (%)
Levodopa/benserazide	20 (100%)
Amantadine	11 (55%)
Piribedil	5 (25%)
Trihexyphenidyl	3 (15%)
Selegiline	2 (10%)
Levodopa/carbidopa	1 (5%)
Pramipexole	1 (5%)

Note: Data are presented as number (percentages).

Figure 1 Flow diagram for the Dixon’s up-and-down method.

Abbreviations: PD, Parkinson’s disease; NPD, non-Parkinson’s disease

Table 3 Minimum Alveolar Concentration-Awake of Sevoflurane

Methods	PD Group (n=20) (%)	NPD Group (n=21) (%)	Differences (95% CI) (%)	p	Relative Median Potency
Dixon’s method	0.47±0.08	0.64±0.10	0.17 (0.10–0.24)	0.003*	–
Probit analysis (95% CI)	0.49 (0.42–0.57)	0.67 (0.59–0.76)	–	–	0.73 (0.38–0.94)

Notes: Data from the Dixon’s up-and-down method are presented as mean ± S.D. Date from the probit analysis are EC₅₀ with (95% confidence interval). *The P value for significance tested by t test is set at 0.05.

Abbreviations: PD, Parkinson’s disease; NPD, non- Parkinson’s disease; CI, confidence interval; EC₅₀, median effective concentration.

Table 4 The Age, Weight, and Sex Between“awake” and “Not Awake” Patients

Parameters	Awake Group (n=20)	Not Awake Group (n=21)	P
Age, yr	56.7±6.3	55.2±6.5	0.457
Sex, male/female	8/11	11/11	0.613
Weight, kg	61.6±5.9	61.4±7.9	0.904

Note: Data are presented as mean ± S.D. or number of subjects.

Table 5 Binary Logistic Regression Analysis for Being Awake

Covariates (n=41)	OR	95% CI for OR		P
		Lower	Upper
Sevoflurane concentration (%)	1.714×10^−8	1.187×10^−12	0.000247	0.0003*
PD group	0.041667	0.003441	0.504522	0.0125*
NPD group (as reference)	–	–	–	–

Notes: *The P value for significance tested by binary logistic regression analysis is set at < 0.05.

Abbreviations: PD, Parkinson’s disease; NPD, non-Parkinson’s disease.

Figure 2 Assessment of responses to verbal command under a predetermined end-tidal concentration of sevoflurane using the Dixon’s up-and-down method in 20 consecutive PD patients (A) and 21 consecutive NPD patients (B). A “no response” concentration is denoted by a solid circle; a “response” concentration is denoted by an open circle; horizontal bars represent crossover midpoints (“no response” to “response”). The MAC_awake values are indicated with red dashed line.

Abbreviations: PD, Parkinson’s disease; NPD, non-Parkinson’s disease.

Figure 3 Dose-response curve from the probit analysis. The minimum alveolar concentration-awake (MAC_awake) of sevoflurane in PD patients was 0.49% (95% CI, 0.42–0.57%). MAC_awake of sevoflurane in the NPD patients was 0.67% (95% CI, 0.59–0.76%).

Abbreviations: PD, Parkinson’s disease; NPD, non-Parkinson’s disease.