Do Longer Surgical Procedures Result in Greater Contamination of Surgeons' Hands?

Abstract

Background: A surgical site infection is a substantial cause of complications in patients. Different methods are being used to decrease surgical site infections; however, these infections still can cause complications, especially in patients undergoing longer operations (> 3 hours). There is evidence that the efficacy of the scrubbing material fades after 3 hours. However, we do not know the longevity of hand cleanliness after application of scrubbing materials in a long operation. It can be postulated that if the surgeon's scrubbed hands are recolonized after a certain time, they may serve as a progressive source of contamination during surgery.

Questions/purposes: We asked: (1) Is there a correlation between surgical duration and hand contamination at the end of surgery? (2) At what point during surgery does hand contamination reach or exceed prescrub levels?

Methods: Three spine surgeons using the same scrubbing technique and materials consisting of chlorhexidine gluconate 1% solution and ethyl alcohol 61% w/w were enrolled in our study. Between December 2014 and April 2015, spine procedures of 3 hours or more, which were the first case of the day, were selected for this study (20 cases). Cases in which glove changing occurred (perforations, reprepping, and redraping) or cultures obtained after scrubbing were positive (indicative of insufficient hand sanitization) were excluded (0% of cases). Twenty cases (100% enrollment) were analyzed. Surgeons' hands were swabbed with sterile cotton tip applicators and 5 mL sterile phosphate-buffered saline before hand scrubbing (prescrub), immediately after hand scrubbing (postscrub), and immediately after surgery (postoperative). Results were reported in colony-forming units per milliliter. The correlation between duration of surgery and hand recontamination was tested by regression analysis of time versus colony-forming units per milliliter. Receiver-operating characteristic curve tested the cutoff point, where recontamination occurred.

Results: With a longer duration of surgery, more colony-forming units are recovered from gloved hands at the end of surgery (R = 0.94, R(2) = 0.89, p = 0.005). The receiver-operating characteristic curve suggested that 5 hours is the cutoff point for hand recolonization. At 5 hours, contamination reached or exceeded prescrub levels (area under the curve, 0.66; 95% CI, 0.23-1.0), whereas before 5 hours, there was no contamination detected at the end of surgery.

Conclusions: Our results show that duration of surgery correlates with hand recontamination and at 5 hours, recolonization of a surgeon's hands become detectable. Recolonization may have started even earlier than 5 hours. However, these levels are not detectable in the laboratory at earlier times.

Clinical relevance: Based on this pilot study, rescrubbing is highly recommended before the fifth hour of an operation, ideally at some point between the fourth and fifth hours.

Future: We also recommend the surgical site infection rates in operations using rescrubbing should be compared with those from surgeries with just the conventional single-scrubbing technique, in a randomized controlled trial, to determine the effectiveness of this novel rescrubbing method.

Figures

Fig. 1

The correlation between duration of the operation and hand contamination is shown. There is a linear correlation with R = 0.94 and R2 = 0.89. CFU = colony forming units.

Fig. 2A–C

(A) A blood agar dish from the prescrub time in an 8-hour case shows some mixed Gram-positive bacterial growth. (B) The blood agar dish at the postscrub time shows no growth at this time, which indicates efficient hand scrubbing. (C) The postoperative blood agar dish shows even more growth with mixed Gram-positive bacteria compared with the prescrub dish.

Fig. 3

The receiver operating characteristic (ROC) curve and its corresponding area under the curve (AUC) are shown. Five hours appears to be the cutoff point for recolonization, with an AUC of 0.66.

Fig. 4

The levels of contamination in CFU/mL for the durations of the operations are shown. The blue bars represent the prescrub times, and the red bars represent the postoperative times. The postscrub times are not presented as there was no growth in any case. CFU = colony forming units.