# Therapy of acute wounds with wIRA

# wIRA for acute operation wounds (Study of the University Hospital Heidelberg,Department of Surgery)

A prospective, randomized, controlled, double-blind study with 111 patients who had undergone major abdominal surgery at the University Hospital Heidelberg, Germany, and thereafter underwent 20 minutes irradiation 2 times per day (starting on the second postoperative day) showed a significant and relevant pain reduction combined with a markedly decreased dose of required analgesics in the group with wIRA and visible light VIS (wIRA(+VIS), appro-ximately 75% wIRA, 25% VIS) compared to a control group with only VIS: during 230 single irradiations with wIRA(+VIS) pain decreased without any exception (median of decrease of pain on postoperative days 2–6 was 13.4 on a 100 mm visual analogue scale VAS 0–100), while pain remained unchanged in the control group (p<0.000001, see Figure 6). The median of decrease of pain on the third postoperative day was 18.5 versus 0.0, the median difference between the groups was 18.4 (99%confidence interval 12.3/21.0), p<0.000001. (Semantic statistical remark in [2], [5].)

The required dose of analgesics was 52–69% lower (median differences) in the subgroups with wIRA(+VIS) compared to the control subgroups with only VIS (median 598 versus 1398 mL ropivacaine, p=0.000020, for peridural catheter analgesia; 31 versus 102 mg piritra-mide, p=0.00037, for patient-controlled analgesia; 3.4 versus 10.2 g metamizole, p=0.0045, for intravenous and oral analgesia, see Figure 7). During irradiation with wIRA(+VIS) the subcutaneous oxygen partial pressure rose markedly by 32% and the subcutaneous temperature by 2.7°C (both measured at a tissue depth of 2 cm), whereas both remained un-changed in the control group. After irradiation, the median of the subcutaneous oxygen partial pressure was 41.6 (with wIRA) versus 30.2 mm Hg in the control group (median difference between the groups 11.9 mm Hg (+39%), 99% confidence interval 8.4/15.4 mm Hg (+28%/+51%), p<0.000001, see Figure 8) and the medi-an of the subcutaneous temperature was 38.9 versus 36.4°C (median difference between the groups 2.6°C, 99% confidence interval 2.1/2.9°C, p<0.000001, see Figure 9). The baseline values (before irradiation) of the subcutaneous oxygen partial pressure rose from the second to the tenth postoperative day by 3.4 versus 0.3 mm Hg (median difference between the groups 3.1 mm Hg (+10%), 99% confidence interval 1.9/3.7 mm Hg, p=0.00051). The baseline values for the subcutaneous temperature rose by 0.4 versus –0.3°C (median differ-ence 0.6°C, 95% confidence interval 0.2/0.8°C, p=0.0074) (effects which endured beyond the time period of the single irradiation).

The overall evaluation of the effect of irradiation, including wound healing, pain and cosmesis, assessed on a VAS (0-100 with 50 as the indifferent point of no effect) by the surgeon (median 79.0 versus 46.8, median difference 27.9, 99% confidence interval 17.2/37.3, p<0.000001) or the patient (79.0 versus 50.2, median difference 23.8, 99% confidence interval 9.5/34.1, p=0.000007) was considerably better in the group with wIRA compared to the control group. This was also true for single aspects: Wound healing assessed on a VAS by the surgeon (medi-an 88.6 versus 78.5, p<0.000001) or the patient (median 85.8 versus 81.0, p=0.040, trend) and cosmetic result assessed on a VAS by the surgeon (median 84.5 versus 76.5, p=0.00027) or the patient (median 86.7 versus 73.6, p=0.00077).

In addition there was a trend towards a lower rate of total wound infections in favor of the wIRA group (3 of 46, 7%, versus 7 of 48, 15%, difference –8%, 95% confidence interval –20%/4%, p=0.21) including late infections fol-lowing discharge. This was due to the different rate of late infections following discharge: 0 of 46 (0%) in the wIRA group and 4 of 48 (8%) in the control group (differ-ence –8%, 95% confidence interval –18%/2%, p=0,12). There was also a trend towards a shorter postoperative hospital stay: 9 days in the wIRA group versus 11 days in the control group (median difference –2 days (–18%), 95% confidence interval –3/0 days, p=0.022).

The principal finding of this study was that postoperative irradiation with wIRA can improve even the normal wound healing process [2], [19].

Figure 6: Decrease of postoperative pain during irradiation in the group with water-filtered infrared-A (wIRA) and visible light (VIS) and in the control group with only visible light (VIS) (Study Heidelberg)

(assessed with a visual analogue scale; given as minimum, percentiles of 25, median, percentiles of 75, and maximum (box and whiskers graph with the box representing the interquartile range), from [2], adapted from [19]).

During 230 single irradiations with wIRA(+VIS) the pain decreased without any exceptions, while pain remained unchanged in the control group (p<0.000001 for any single documented day as well as for all the days).

Figure 7: Required dose of analgesics of the subgroups with water-filtered infrared-A (wIRA) and visible light (VIS) in relation to the control subgroups with only visible light (VIS) (medians of the control subgroups = 100) (Study Heidelberg)

(given as minimum, percentiles of 25, median, percentiles of 75, and maximum (box and whiskers graph with the box representing the interquartile range), adapted from [2], data taken from [19]).

The required dose of analgesics was 52–69% lower (median differences) in the subgroups with wIRA(+VIS) compared to the control subgroups with only VIS.

Figure 8: Subcutaneous oxygen partial pressure at a tissue depth of 2 cm on the postoperative days 2 and 10 in the group with water-filtered infrared-A (wIRA) and visible light (VIS) and in the control group with only visible light (VIS)

(Study Heidelberg)

(given as minimum, percentiles of 25, median, percentiles of 75, and maximum (box and whiskers graph with the box representing the interquartile range); adapted from [2], [19]). During irradiation with wIRA(+VIS), the subcutaneous oxygen partial pressure rose markedly by more than 30%, whereas it remained unchanged in the control group.

Figure 9: Subcutaneous temperature at a tissue depth of 2 cm on the postoperative days 2 and 10 in the group with water-filtered infrared-A (wIRA) and visible light (VIS) and in the control group with only visible light (VIS) (Study Heidelberg)(given as minimum, percentiles of 25, median, percentiles of 75, and maximum (box and whiskers graph with the box representing the interquartile range); adapted from [2], [19]). During irradiation with wIRA(+VIS) the subcutaneous temperature rose markedly by approximately 2.7°C, whereas it remained unchanged in the control group.