Remifentanil at a Relatively Elevated Dose in Active Phase is Safe and More Suitable Than Fixed Lower Dose for Intravenous Labor Analgesia

Figures & data

Figure 1 Flow chart of the study.

Table 1 Demographic Characteristics of Parturients

Characteristics	Group A (n = 56)	Group B (n = 59)	P-value
Age (year)	29.98±4.03	30.63±3.88	0.961
Weight (kg)	66.46±7.17	64.19±5.81	0.168
Height (cm)	161.11±5.57	159.02±5.20	0.465
Body mass index (kg/m^2)	26.51±2.24	25.78±1.87	0.158
Gestational week	39.25±1.20	39.38±1.31	0.690
Parity, multiparous	23 (41.1%)	22 (37.3%)	0.678
Multiple pregnancy history	28 (50%)	27 (45.8%)	0.649
Labor induction history	30 (53.6%)	31 (52.5%)	0.912

Note: Data expressed as mean ± SD or n (%).

Table 2 Comparison of Pain Score, Sedation Score and Satisfaction Score

Parameters	Group A (n = 56)	Group B (n = 59)	P-value
Pain score before analgesia	8.32±0.61	8.34±0.60	0.877
Mean Pain score in latent phase	3.41±0.75	3.43± 0.73	0.867
Mean Pain score in active phase	6.53±0.69	5.45±0.49	0.000*
Lowest pain score in latent phase	2.57±0.98	2.44±1.15	0.515
Lowest pain score in active phase	5.88±0.89	4.69±0.73	0.000*
Sedation score before analgesia	1.00±0.00	1.00±0.00	/
Sedation score in latent phase	2.10±0.20	2.20±0.17	0.805
Sedation score in active phase	1.30±0.21	2.00±0.00	0.000*
Overall satisfaction score	7.05±0.55	8.81±0.39	0.000*
The first labor stage duration (minutes)	270.00±123.21	317.28±157.04	0.103
The duration of latent phase (minutes)	149.29±65.36	172.37±85.09	0.105
The duration of active phase (minutes)	118.92±62.66	144.91±98.74	0.093
The bolus push times	143.16±63.79	125.66±59.58	0.681
Total dose (mg)	1.95±0.94	2.12±1.11	0.389

Note: Data expressed as mean ± SD, *Compared with group A, P<0.05.

Figure 2 Sedation score and Pain score in latent and active phase between two groups. (A) Sedation score of two groups at different time points during latent phase. (B) Sedation score of two groups at different time points during active phase. (C) Pain score of two groups at different time points during latent phase. (D) Pain score of two groups at different time points during active phase. (*Compared with group B, P < 0.05).

Table 3 Maternal Adverse Reactions of Two Groups

Parameters	Group A (n = 56)	Group B (n = 59)	P-value
Hypoxemia (SPO2<94%)	0 (0%)	0 (0%)	/
Nausea	8 (14.3%)	9 (15.3%)	0.884
Vomiting	0 (0%)	0 (0%)	/
Drowsiness	17 (30.4%)	20 (33.9%)	0.685
Dizziness	20 (35.7%)	26 (44.1%)	0.361
Confusion	0 (0%)	0 (0%)	/
Hypotension	0 (0%)	0 (0%)	/
Bradycardia	3 (5.4%)	7 (11.9%)	0.216
Itching	0 (0%)	0 (0%)	/

Note: Data expressed as n (%).

Table 4 Comparison of the Fetal and Neonatal Adverse Reactions

Parameters	Group A (n = 56)	Group B (n = 59)	P-value
Non-reassuring FHR	0 (0%)	0 (0%)	/
Resuscitation	0 (0%)	0 (0%)	/
Naloxone requirement	0 (0%)	0 (0%)	/
1-minute Apgar score	All 10	All 10	1.000
5-minute Apgar score	All 10	All 10	1.000
10-minute Apgar score	All 10	All 10	1.000
Umbilical artery pH	7.24±0.89	7.24±0.80	0.608
Umbilical artery PaO2 (mmHg)	22.53±7.16	22.94±8.05	0.772
Umbilical artery PaCO2 (mmHg)	52.39±13.44	52.54±11.71	0.949
Lactic acid (mmol/L)	5.15±1.73	4.80±1.40	0.234

Note: Data expressed as mean ± SD or n (%).

Data Sharing Statement

The data presented in this study are available on request from the corresponding author (Jin Yu; [email protected]). The data are not publicly available because this was a clinical trial containing information that could compromise the privacy of research participants.