In China the use of analgesics and sedation following paediatric cardiac surgery is variable; average pain scores are reported to be good but over-sedation is common
- 1University of Lausanne, IUFRS, Lausanne, Switzerland
- 2HESAV, University of Applied Sciences, Western Switzerland
- Correspondence to: Professor Anne-Sylvie Ramelet
University of Lausanne, IUFRS, Rte de la Corniche 10. Lausanne, 1011, Switzerland;
Implications for practice and research
The trajectory of both pain intensity and sedation level is an important consideration when caring for children following cardiac surgery.
International standards recommend preventive analgesia should be incorporated into care pathways for children following cardiac surgery.
Neuromuscular blockage should be assessed using quantitative valid methods, such as the train-of-four.
The prevalence of pain following cardiac surgery in children remains excessively high worldwide.1 ,2 It is estimated that 70% of children experience moderate to severe pain postcardiac surgery in China. Effective pain management should be a priority in the child's care following surgery.
Bai and Hsu's study aimed to describe the trajectory of pain intensity and sedation level in Chinese children after cardiac surgery. The study was undertaken in a 47-bed cardiac intensive care unit (ICU) within a tertiary hospital for children in China. Children were included in the study if they were between birth and 7 years of age, and had undergone cardiac surgery requiring an ICU stay of more than 2 days. Pain and sedation scores were measured 2 hourly during the 3 consecutive days postcardiac surgery, using the validated Chinese versions of the FLACC and the COMFORT behaviour scale (COMFORT-B), respectively. Assessments were undertaken 1 h after standard procedures such as endotracheal suctioning, respiratory therapy and the administration of medication.
Of the 170 children who participated in the study, 75.3% received neuromuscular blockage agents and 64.1% received analgesia. Continuous intravenous opioid was the analgesia most commonly used (55.9%); 35.9% of children did not receive analgesia. Although 61% of the children were recorded as having a pain score greater than four at least once, the mean pain scores ranged from 1.3 (SD=1.9) to 0.6 (SD=0.9) (F=23.57, p<0.001). Children experienced more pain on the day of surgery than subsequent postoperative days. Analysis of the sedation scores found half of the children (50.3%) were over-sedated and less than 1% of children were under-sedated.
The study addresses important issues relating to the management of postoperative pain in children. Bai and Hsu used standardised methods of translation to develop the Chinese version of the FLACC and the COMFORT-B. The justification for using both tools is unclear, although it is implied that effective sedation contributes to a child's comfort postoperatively. However, the COMFORT-B scale has shown to be useful to assess both pain and sedation.3 To discriminate between the two, Bai and Hsu recommend nurses make their own judgement about the child's pain using a visual analogue scale and the level of sedation using the Nurse Interpretation of Sedation Score.3 ,4 Nurses use a range of factors to interpret pain and sedation scores, such as the child's clinical presentation, current treatment and symptoms, when making clinical decisions about pain and sedation in critically ill patients.5 How nurses interpreted the COMFORT-B score to make decision about treatment is unclear in Bai and Hsu's study.
The study reported overall low mean pain scores, which may be a result of adequate analgesia, over-sedation or residual neuromuscular blockade. First, although the majority of children received analgesics, it is unclear whether additional boluses of analgesics and/or sedatives were administered prior to care interventions. The administration of bolus analgesic could have influenced the results because the assessments were performed 1 h after potentially painful procedures. International standards of best practice would recommend preventive analgesia. Second, over-sedation (COMFORT-B score of ≤10) was reported in a high number of children and may have resulted in low pain scores, since sedative agents can mask pain behaviour. In addition, for the 75.3% of children who received muscle relaxants, pain and sedation assessment was performed 30 min after vecuronium was given. However, residual neuromuscular blockade can remain in the circulation hours after a single dose of intermediate-acting drugs, such as vecuronium.6 Residual neuromuscular blockade will impair ventilation and behavioural responses to pain. Therefore, monitoring of neuromuscular blockade in ICU should not be undertaken based on drug half-life, but assessed using quantitative valid methods, such as the train-of-four test. In the train-of-four test, absence of neuromuscular blockade would be indicated if four equal muscle contractions were observed following four consecutive stimuli delivered along the path of a nerve. In summary, the results of the Bai and Hsu study should be interpreted with caution.