Gas kinetics during nitrous oxide analgesia for labour

Einarsson, S.; Stenqvist, O.; Bengtsson, Anders; Norén, Håkan; Bengtson, J. P.

doi:10.1111/j.1365-2044.1996.tb07790.x

Cited by 21 publications

(14 citation statements)

References 25 publications

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“…low tidal volume during the contraction pauses instead of bradypnoea and hypoventilation. The ETCO 2 of 3.7 measured during contractions with nitrous oxide is comparable with the ETCO 2 reported by Einarsson et al (1996) suggesting pain induced hypocapnia. This was partially corrected by remifentanil analgesia.…”

Section: Respiratory Effectssupporting

confidence: 85%

“…This was partially corrected by remifentanil analgesia. The gas sampling method includes a possibility of marked dilution but the similarity with the results in the study by Einarsson et al (1996) suggest this did not substantially alter the findings in the present study. This result should be confirmed in future studies with blood gas analysis.…”

Section: Respiratory Effectssupporting

confidence: 62%

“…This is supported by the fact that the highest exhaled N 2 O concentration during the PCA boluses was only 30%. This was somewhat lower than the maximum ETN 2 O of 36.5% reported by Einarsson et al (1996). It is possible that coaching the parturient to anticipate the forthcoming uterine contraction would have resulted in a better analgesia, but it is felt that the manner in which nitrous oxide was used in our study reflects the routine practice on many labour wards.…”

Section: Fhr Tracings Delivery Mode Uaph and Apgar Scoresmentioning

confidence: 60%

“…Unfortunately, no details on pharmacodynamics were given. Einarsson et al (1996) measured gas kinetics during the intermittent inhalation of 50% and 70% nitrous oxide, noting that at the end of an inhalation of 58 seconds, the end tidal nitrous oxide (ETN 2 O) reached 36.3% and 54.5%, respectively. The concentration of nitrous oxide in exhaled gas diminished within 30 seconds after the intake was discontinued.…”

Section: Nitrous Oxidementioning

confidence: 99%

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Intravenous patient-controlled analgesia with remifentanil in early labour

Volmanen¹

2011

Acta Anaesthesiologica Scandinavica

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Cover design Raimo Ahonen JUVENES PRINT TAMPERE 2010Volmanen, Petri, Intravenous patient controlled analgesia with remifentanil in early labour. AbstractIn four prospective clinical trials, 114 parturients used intravenous patient-controlled remifentanil analgesia during the 1 st stage of labour. The median effective dose per bolus was ascertained to be 0.4 μg/kg and the pain scores were reduced with this by a median of 2 on a numerical scale (0-10). Compared with nitrous oxide, 15 parturients included in a cross-over study reported a larger reduction in pain scores during remifentanil analgesia (1.5 vs. 0.5, p = 0.001) and better pain relief scores (2.5 vs. 0.5 on a ranked five point scale 0-4, p < 0.001). In a parallel study including 45 parturients, epidural analgesia (EDA, 20 ml bupivacaine 0.625 mg/ml and fentanyl 2 μg/ml) was associated with lower pain scores (5.2 vs. 7.3 with remifentanil, p = 0.004) but variables related to satisfaction with analgesia (pain relief score, proportion of mothers with desire to continue with the given medication and termination of the study due to inadequate pain relief) were similar. A comparison of two methods for timing the remifentanil bolus during the uterine contraction cycle suggested that delaying the bolus does not improve analgesia. A period effect was noted in the cross-over trial with higher pain scores and increased drug consumption during the second study period suggesting acute hyperalgesia.Side effects of remifentanil analgesia included respiratory depression warranting oxygen supplementation in 33% of parturients. Sedation was experienced by the parturients using remifentanil and this was scored as stronger than sedation during nitrous oxide and EDA. The number of parturients with nausea did not increase during remifentanil analgesia. Other maternal side effects included dizziness, a difficulty in visual focusing and itching. Foetal heart rate tracing abnormalities were noted. The incidence of abnormal tracings and decreased UapH were not different, however, from that observed during nitrous oxide or EDA. Apgar scores at 1 and 5 minute indicated no neonatal depression. Keywords

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Section: Respiratory Effectssupporting

confidence: 85%

Section: Respiratory Effectssupporting

confidence: 62%

Section: Fhr Tracings Delivery Mode Uaph and Apgar Scoresmentioning

confidence: 60%

Section: Nitrous Oxidementioning

confidence: 99%

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Intravenous patient-controlled analgesia with remifentanil in early labour

Volmanen¹

2011

Acta Anaesthesiologica Scandinavica

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“…Unlike opioids, it does not depress respiration (Rosen, 2002). Nitrous oxide rapidly takes effect (Latto et al, 1973) and is quickly reversible on discontinuation of therapy (Latto et al, 1973;Einarsson et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Nitrous oxide versus pethidine with promethasine for reducing labor pain

Teimoori¹,

Sakhavar²,

Mirteimoori³

et al. 2011

Afr. J. Pharm. Pharmacol.

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Systemic opioids are widely used for the relief of labor pain. Self-administered nitrous oxide with concentration of 50% is a new form of analgesia. The aim of this study was to compare the analgesic efficacy and side effects of the patient controlled inhaled nitrous oxide (50% ''Entonox'') with systemic intramuscular pethidine, in reducing pain during normal vaginal labor in Iranian population. In a randomized controlled study, the analgesic efficacy of inhaled 50% nitrous oxide (Entonox) was evaluated as compared to intra muscular pethidine for reducing labor pain among 100 women undergoing normal vaginal delivery. Mean maternal age was 26.2 and 27.2 years in entonox and pethidine groups, respectively. Duration of first and second stages was significantly shorter in patients receiving nitrous oxide as analgesia as compared to pethidine group (P < 0.05). Pain severity according to visual analog scale (VAS) score was significantly lower in patient that received nitrous oxide (P = 0.0001). We also showed significantly higher satisfaction of pain reduction in nitrous oxide group during labor (P = 0.01). No significant difference was observed among the groups regarding neonatal complications. Although, nitrous oxide is certainly not a potent analgesic, we found that it has more beneficial effects than pethidine in parturient women which is yet to be cleared.

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