Postoperative wound assessment in cattle: How reliable is the back hand palpation?

Abstract

Background: As part of clinical wound assessment in bovine surgery, discrepancies in skin temperature are evaluated by placing the back of the hand on the area to be examined. Generally, an increased skin temperature at the wound site for a prolonged period is considered as an indicator of impaired wound healing. The aim of this study was to verify the reliability of palpation under bovine practice conditions using laparotomy as an example. Fourteen cows (German Holstein) with a left displacement of the abomasum (LDA) without other severe concurrent diseases were examined preoperatively and once daily for ten days after surgery. The skin temperature of the wound site in the right flank was assessed by palpation, followed by thermographic evaluation using an infrared camera after a 45-min acclimatisation period, under standardised conditions in a closed examination room daily for 10 days.

Results: All the incisions healed without clinical detectable perturbances. The ambient temperature range during the study period was 7.8 - 24.1 °C. Two groups were retrospectively defined according to the ambient temperature: high ambient temperature (HT group; median: 20.2 °C 25/75 quartile: 18.5 °C / 21.7 °C; n = 6) and low ambient temperature (LT group; 10.8 °C; 9.4 °C / 12.8 °C; n = 8). The temperature differences (Δϑ) between the mean skin temperature of the wound site and a defined reference area cranial to the wound were assessed. A significant negative correlation was found between the ambient temperature (ϑ_Amb) and Δϑ (r=-0.51; P < 0.001). The Δϑ was postoperatively higher in the cows in the LT group (median of the individual animals 0.8-2.5 °C) than in the HT group (0.1-0.5 °C; P < 0.05). In contrast to the thermographic findings, manual palpation rarely detected local hyperthermia (> 1 °C) at the wound site (sensitivity 0.20; specificity 0.96).

Conclusions: The infrared thermography provides a more reliable assessment of temperature changes at the wound site in comparison to manual palpation. The ambient temperature markedly affects the extent of local hyperthermia at the wound site.

Keywords: Cows; Infrared imaging; Laparotomy; Palpation; Skin temperature; Thermography; Wound healing.

Fig. 1

IR image presented with the software IRBIS®3 plus (a) and digital picture (b) of the right flank of cow postoperatively. Schematic illustration of the defined skin areas: WA = wound area, RA = reference area cranial of the laparotomy wound, RB = measured area of the reference body

Fig. 2

Schematic illustration of the measuring set-up for infrared thermography. The reference body was continuously positioned at a specific point in front of the IR camera and in this way it appeared in each IR image of the right flank of the cow

Fig. 3

Distribution of thermographic temperature differences (Δϑ) for all cows and for both groups in detail. The shaded blue area of the columns indicates the cows diagnosed palpatorically showing no increased warmth; the shaded red area indicates those cows diagnosed showing increased warmth. Total: includes all the cows (n = 14; 140 measurements); LT: Group of cows whose measurements were taken at low ambient temperatures (n = 8; 80 measurements); HT: Group of cows whose measurements were taken at high ambient temperatures (n = 6; 60 measurements)