Nursing surveillance moderates the relationship between staffing levels and pediatric postoperative serious adverse events: a nested case-control study

Background: Insufficient monitoring, surveillance, and nurse staffing levels are system factors that may contribute to serious adverse events and deterioration in hospitalized patients. Limited data have examined the relationship between these factors and postoperative outcomes, particularly in the pediatric setting.

Objectives: This retrospective, case-control study examined the relationship between surveillance, staffing, and serious adverse events in children on general care postoperative units. The following hypotheses were tested: (1) the relationship between patient factors and surveillance would be moderated by staffing (i.e., registered nurse hours per patient per shift), and (2) the relationship between staffing and serious adverse events would be mediated by surveillance.

Methods: With institutional review board approval, children with serious adverse events on a general care unit were identified from institutional event databases, and procedure-matched controls were randomly selected from surgical lists. Demographics, co-morbidities, perioperative information, frequency of postoperative monitoring and assessments (i.e., surveillance), and registered nurse hours per patient per shift (i.e., staffing) were recorded. Regression models were used to test the hypotheses.

Results: The Event Group included 98 children and the Control Group, 158. Registered nurse hours per patient per shift were lower for the Event Group (2.99 ± 0.59) compared to Controls (3.38 ± 1.23, p=0.002). The number of assessments/shift was higher for the Event Group (4.27 ± 2.8) compared to Controls (2.85 ± 1.9; p<0.001), as was use of continuous pulse oximetry (78% vs. 58%, respectively; p=0.001). Staffing moderated the relationship between comorbidity and surveillance (r(2)=0.192, p<0.001) revealing a significant relationship at lower staffing but not higher. Surveillance did not mediate the relationship between staffing and events, but moderated it (r(2)=0.435; p<0.001) showing no relationship at lower surveillance levels.

Conclusions: Nurse staffing levels moderated the relationship between patient factors and surveillance demonstrating that this association is dependent on staffing levels. The association between staffing and adverse outcomes was dependent on the level of surveillance. Increased surveillance based on recognition of deterioration may have facilitated rescue of children in this setting, even during times of lower staffing.