Pulse oximeter-induced digital injury: Frequency rate and possible causative factors

Objective: To study the frequency rate of and factors associated with pulse oximeter-induced digital injury (PIDI). Design: Prospective descriptive study. Setting: Surgical intensive care unit of a university hospital. Patients: All patients with a length of stay of >2 days. Interventions and Main Results: We monitored 125 patients by using a pulse oximeter with a nondisposable clip-on probe changed every 3-4 hrs from one finger to another. Daily inspection was performed with special attention to digital injury. Factors implicated in the pathogenesis of PIDI, such as va sopressor therapy, hypotension, hypoxia, hypothermia, and arterial cannulat ion of the radial or ulnar artery were recorded daily. A total of 22 patien ts received norepinephrine and dopamine, 34 patients were given dopamine, a nd 69 patients did not receive vasoactive drugs. PIDI developed in 6 of 125 patients, five in the norepinephrine/dopamine group, one in the dopamine g roup, and none in the patients not receiving vasopressors. When comparing t he frequency rate of PIDI in patients receiving norepinephrine (5 of 22) wi th patients not receiving norepinephrine (1 of 103) the relationship betwee n the use of norepinephrine and PIDI is significant (p < .001). However, th is relationship may also be explained by the fact that patients in the nore pinephrine group were more severely ill than patients not requiring norepin ephrine were. This is reflected by a higher median severity of illness scor e (Simplified Acute Physiology Score II) (p = .001), median duration of hyp otension (p < .001), median number of saturation drops (p < .001), and high er mortality rate (p < .001). Hypothermia did not occur in any of the patie nts. There was no significant difference between the median right-left diff erence in duration of arterial cannulation between the two subgroups (p = . 8). In all surviving patients, PIDI healed without permanent damage. Conclusions: In the studied population of critically ill patients in a surg ical intensive care unit, the frequency rate of PIDI was 5% (6 of 125). Alt hough an association with the use of norepinephrine was found, this small n umber of cases does not allow definite statistical conclusions concerning a relationship between the possible causative factors and PIDI. However, sev erely ill patients, as indicated by their need for more aggressive vasopres sors, are more likely to develop PIDI. In survivors, PIDI healed without se quelae.