Abstract
Purpose
To determine, after Caesarean delivery, uterine contractility and blood pressure following intravenous (iv) and intramyometrial (imy) injection of oxytocin.
Methods
In a double-blind clinical trial 40 parturients scheduled for elective Caesarean section with spinal anaesthesia were randomized into two equal groups. One litre Ringer’s lactate was administerediv before intrathecal injection of 1.7 ml bupivacaine 0.75% and 0.3 mg morphine. All patients received simultaneous iv andimy injections after removal of the placenta. Patients in Group 1 received 5 IU (10 IU·ml−1) oxytociniv and 2 ml salineimy; Group 2 patients received 0.5 ml saline iv and 20 IU oxytocin into the myometrium. Baseline systolic blood pressure (SBP) and heart rate were measured before delivery and at one minute intervals for 15 min after injection of study solutions. Uterine contractility was assessed at 1, 2, 4, 6, 8, 10 and 15 min after oxytocin injection. Haemoglobin concentration before surgery and on first post-operative day was also recorded.
Results
Mean decrease in systolic blood pressure (SBP) one minute after oxytocin was 8.4 mmHg in Group 1vs 14.6 mmHg in Group 2 (P < 0.001). Systolic blood pressure returned to baseline two minutes after oxytocin in Group 1 and after three minutes in Group 2. Uterine contractility and change in haemoglobin concentration were similar in both groups.
Conclusion
Intramyometrial administration of 20 IU oxytocin after Caesarean delivery is associated with more severe hypotension than is iv injection of 5 IU oxytocin. Route of oxytocin injection did not affect uterine tone.
Résumé
Objectif
Déterminer la contractilité utérine et la tension artérielle qui suivent une injection intraveineuse (iv) et intramyométriale (imy) d’ocytocine après un accouchement par césarienne.
Méthode
Lors d’un essai clinique en double aveugle, 40 parturientes devant subir une césarienne élective et recevoir une anesthésie péridurale ont été réparties de façon aléatoire en deux groupes égaux. Un litre de lactate de Ringer a été administré iv avant une injection intrathécale de 1,7 ml de bupivacaïne à 0,75% et 0,3 mg de morphine. Toutes les patientes ont reçu des injections simultanées iv et imy après l’extraction du placenta. Les patientes du groupe 1 ont reçu 5 Ul (10 Ul·ml−1) d’ocytocine iv et 2 ml de solution salée imy; les patientes du groupe 2 ont reçu 0,5 ml de solution salée iv et 20 Ul d’ocytocine imy. La tension artérielle systolique (TAS) de base et la fréquence cardiaque ont été mesurées avant l’accouchement et à intervalles d’une minute pendant 15 minutes après l’injection des solutions-test. La contractilité utérine a été évaluée à 1, 2, 4, 6, 8, 10 et 15 minutes après l’injection d’ocytocine. On a aussi enregistré la concentration d’hémoglobine avant la chirurgie et le premier jour postopératoire.
Résultats
La baisse moyenne de la tension artérielle systolique (TAS), une minute après l’injection d’ocytocine, était de 8,4 mmHg dans le groupe 1vs 14,6 mmHg dans le groupe 2 (P < 0,001). Également après l’ocytocine, il a fallu deux minutes pour le groupe 1 et trois minutes pour le groupe 2 avant de retrouver la tension artérielle de base. La contractilité utérine et le changement dans la concentration d’hémoglobine ont été similaires dans les deux groupes.
Conclusion
Ladministration intramyométriale de 20 Ul d’ocytocine après une césarienne est associée à une hypotension plus sévère qu’avec une injection iv de 5 Ul d’ocytocine. La voie d’administration de l’ocytocine n’a pas affecté la tonicité utérine.
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Dennehy, K.C., Rosaeg, O.P., Cicutti, N.J. et al. Oxytocin injection after Caesarean delivery: intravenous or intramyometrial?. Can J Anaesth 45, 635–639 (1998). https://doi.org/10.1007/BF03012092
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DOI: https://doi.org/10.1007/BF03012092