Influence of the number of nurses on survival in multiple system organ failure

Introduction

Although requirements of human resources in the ICU are well defined (six nurses per bed in level III and four nurses per bed in level II ICUs), these guidelines are not followed in many countries and evidence is also lacking [1]. The aim of this study was to investigate the effect of the number of nurses on the survival in multiple system organ failure (MSOF) on an eight-bed level-III ICU.

Methods

As the number of nurses was doubled in 2003 (from 14 to 29, increasing the ICU bed/nurse ratio from 1.7 to 3.6) we screened the records of all patients from 2001 to 2005 admitted to the ICU. Those suffering from at least two organ failures as defined by the multiple organ dysfunction score were selected for analysis [2]. In addition to demographic and outcome variables, data were also collected on practice variations, such as timing of tracheostomy, invasive monitoring and antimicrobial management. Mortality and yearly demographic data were compared with Fisher's exact test and independent-sample t tests, respectively. Multivariate, forward stepwise logistic regression was performed to evaluate the independent predictors of survival.

Results

Out of 2,169 patients, 449 were found to have MSOF. There was no significant difference in demographics over the years. Mortality significantly decreased after 2003: 2001, 92.8%; 2002, 89.9%; 2003, 84% (not significant); 2004, 75.3%; 2005, 65.4% (P = 0.001). Survival was significantly influenced by the number of qualified nurses (OR = 1.20 (95% CI: 1.10–1.31), P < 0.001), simplified acute physiology score II (OR = 0.98 (95% CI: 0.96–0.99), P = 0.014), and the number of blood cultures (OR = 1.13 (95% CI: 1.05–123), P = 0.002).

Conclusion

These results suggest that although the ICU bed/nurse ratio is still far from ideal, the number of nurses do play an important role in the survival of patients in MSOF. According to these data, optimising the nurse:patient ratio is not only a professional goal but also a moral duty for those who are in charge of providing healthcare resources.