Influence of surgical technique on early postoperative hypoxaemia in children undergoing elective palatoplasty

The incidence of hypoxemia during surgery: evidence from two institutions

PURPOSE

The incidence of hypoxemia in patients undergoing surgery is largely unknown and may have a clinical impact. The objective of this study was to determine the incidence of intraoperative hypoxemia in a large surgical population.

METHODS

We performed a retrospective study of electronically recorded pulse oximetry data obtained from two large academic medical centres. All adults (age ≥ 16 yr) undergoing non-cardiac surgery during a three-year period at the two hospitals were included in the analysis. Our main outcome measure was the percentage of patients with episodes of hypoxemia (SpO(2) < 90) or severe hypoxemia (SpO(2) ≤ 85) for two minutes or longer during the intraoperative period (induction of anesthesia, surgery, and emergence).

RESULTS

We evaluated 95,407 electronic anesthesia records at the two hospitals. During the intraoperative period, 6.8% of patients had a hypoxemic event, and 3.5% of patients had a severely hypoxemic event of two consecutive minutes or longer. Seventy percent of the hypoxemic episodes occurred during either induction or emergence- time periods that represent 21% of the total intraoperative time. From induction to emergence, one episode of hypoxemia occurred every 28.9 hr, and one episode of severe hypoxemia occurred every 55.7 hr of intraoperative time.

CONCLUSION

Despite advances in monitoring technology, hypoxemia continues to occur commonly in the operating room and may be a serious safety concern because of its potential impact on end organ function and long-term outcomes. Further studies are needed to improve our understanding of the clinical impact of intraoperative hypoxemia and the strategies that will be most useful in minimizing its occurrence.

Risk factors in children having palatoplasty

Palatoplasty carries a relatively high risk of hypoxaemia. We prospectively evaluated 23 children having elective surgery for cleft palate. Intubation was uneventful in 15 patients and the lowest pulse oximetry levels (mean: 93% (range: 100-57)) were less affected than those at extubation (mean: 83% (range: 100-21)) which was uneventful in 10. Establishing a free airway was associated with increased difficulties in patients with Pierre Robin sequence (n = 4). All children who had had a recent airway infection or a parent who smoked (n = 8) had some degree of difficulty in intubation, or extubation, or in both. Increased attention paid to these latter, avoidable, factors may potentially reduce the anaesthetic hazards in this group of patients, who are at increased risk.

Identification of children at high anaesthetic risk at the time of primary palatoplasty

Closure of the palate is an operation with a higher risk of postoperative hypoxaemia than other plastic surgical procedures. An increase in anaesthetic complications was noticed among our children with a cleft palate who were operated on with a palatoplasty, and this was further investigated. The records of 154 patients operated on between 1979 and 1996 were eligible for the study. A total of 128 had isolated cleft palate (ICP), 19 had Pierre Robin syndrome (PRS), and seven had other identified syndromes (IS). The results showed that the risk of anaesthetic complications was four times greater when the operation was done when the child was less than 1 year old, and there was a sixfold increase when a more elaborate velopharyngoplasty technique was used. Children with Pierre Robin syndrome were further classified according to the degree of neonatal difficulties. The 12 children with most severe problems were at increased risk. When the diagnostic criteria as well as the type of operation were taken into account the incidence of anaesthetic complications was 7/11, which was the highest risk encountered in the present study. When the first operation on the palate in children with Pierre Robin syndrome is planned, it should be based on a classification of neonatal problems and an investigation of their clinical condition. In children at risk the palatoplasty procedure should be postponed until the age of 12-18 months.