Investigating the effect of cryotherapy on the discomfort of sterile water injections

INTERVENTION: Women in labour and receiving four intradermal injections of 0.1 ‐ 0.3 millilitres of sterile water for management of back pain in labour assessed by visual analogue scale equal to or greater than 6 will receive either the application of a vapocoolant spray applied to the injections sites. The vapocoolant spray PainEase® is manufactured by Gebauer. PainEase® spray and contains 1,1,1,3,3‐Pentafluoropropane and 1,1,1,2‐Tetrafluoroethane which are non‐flammable and. unlike ethyl chloride. are not absorbed through the skin and therefore safe to use in pregnancy. The cooling effect occurs through the rapid evaporation. The injection points will be sprayed with PainEase® spray at a distance of 8 cms from skin for a period of five to eight seconds immediately prior to administering the injections. The intervention will be delivered by two midwives working concurrently. Participants in the second intervention group will receive the application of a chemical cold pack to the injection area for 10 minutes prior to the administration of the water injections. Compliance with the administering protocol for both interventions will be recorded on the case report form. CONDITION: Anaesthesiology ‐ Pain management Labour pain; ; Labour pain Reproductive Health and Childbirth ‐ Childbirth and postnatal care PRIMARY OUTCOME: The mean difference in Visual Analogue Scale (VAS) scores of injection pain of water injections compared to control[At time of injections ] SECONDARY OUTCOME: Duration of active first stage labour from 4cm to 10cm cervical dilation assessed through data linkage to perinatal records [At time of birth ] Duration of labour from birth of infant to birth of placenta assessed through data linkage to perinatal records [At birth] Duration of second stage labour from 10cm to birth of infant assessed through data linkage to perinatal records [At birth of infant] Estimated blood loss at birth in milliltres assessed through data linkage to perinatal records [At birth] Length of stay in hospital (hours) assessed through data linkage to perinatal records [At discharge from hospital ] Maternal satisfaction as measured by a postnatal survey designed specifically for the study [In the first two weeks following birth ] Mean difference in skin temperature between intervention and control groups measured by infrared surface thermometer [Immediately following injections ] Mean difference in skin temperature between intervention and control groups measured by infrared surface thermometer [prior to application of either vapocoolant or cold pack ] Neonatal Apgar score[Five minutes post birth] Neonatal Apgar score[One minute post birth] Non‐pharmacological analgesia use prior to and after randomisation (water immersion, shower, mobility, massage, birthball, hypnobirthing) assessed through data linkage to perinatal records [At time of birth ] Number of women reporting an at least 30% reduction in self reported VAS scores of back pain[At 120 minutes post injection ] Number of women reporting an at least 30% reduction in self reported VAS scores of back pain[At 30 minutes post injection ] Number of women reporting an at least 30% reduction in self reported VAS scores of back pain[At 60 minutes post injection ] Number of women reporting an at least 30% reduction in self reported VAS scores of back pain[At 90 minutes post injection ] Number of women reporting an at least 50% reduction in self reported VAS scores of back pain[At 120 minutes post injection ] Number of women reporting an at least 50% reduction in self reported VAS scores of back pain[At 30 minutes post injection ] Number of women reporting an at least 50% reduction in self reported VAS scores of back pain[At 60 minutes post injection ] Number of women reporting an at least 50% reduction in self reported VAS scores of back pain[At 90 minutes post injection ] Other pharmacological use prior to and after randomisation (opiods, nitrous oxide inhalation, epidurals) assessed through data linkage to perinatal records [At birth of infant] Proportion of infants experiencing any Intensive Care Nursery (ICN) or Special Care Nursery (SCN) admission assessed through data linkage to perinatal records [At infant discharge ] Proportion of infants experiencing resuscitation (Intermittent positive pressure ventilation, CPR, medications) assessed through data linkage to perinatal records [At birth] Proportion of women experiencing an assisted vaginal birth assessed through data linkage to perinatal records [At birth] Proportion of women experiencing an augmentation of labour assessed through data linkage to perinatal records [At birth ] Proportion of women experiencing an unassisted vaginal birth assessed through data linkage to perinatal records [At birth] Proportion of women experiencing caesarean section birth assessed through data linkage to perinatal records [At birth] Proportion of women fully breastfeeding at discharge assessed through data linkage to perinatal records [At discharge from hospital ] The mean difference in Visual Analogue Scale (VAS) scores of back pain following water injections compared to control [At 120 minutes post injection ] The mean difference in Visual Analogue Scale (VAS) scores of back pain following water injections compared to control [at 30 minutes post injection ] The mean difference in Visual Analogue Scale (VAS) scores of back pain following water injections compared to control [At 60 minutes post injection ] The mean difference in Visual Analogue Scale (VAS) scores of back pain following water injections compared to control [At 90 minutes post injection ] INCLUSION CRITERIA: In labour (spontaneous or induced) Are equal to or greater than 16 years of age Have a term singleton pregnancy (between 37 and 42 weeks gestation) Have a fetus in a cephalic (head down) presentation Experience back pain assessed by visual analogue scale VAS as equal to or greater than 6 Are able to provide informed consent