Figure 1 Induction of a suction blister by applying a negative pressure to a suction cup with an opening diameter of 6 mm

Figure 2 Bar chart with mean va-

lues and standard deviation for

the duration of the suction blis-

ters‘ final shape at various pres-

sures [min] (n=6)

* with a 30 min. lead time at 35

kPa

Figure 3 Representative macroscopic images of fully developed suction blisters inducted

by application of various negative pressures between 45 and 80 kPa with or without a 30

min lead time with a reduced pressure.

45 kPa

80 kPa

60 kPa

80 kPa with a 30 min. lead time at 35 kPa

Increasing the negative pressure in the model of generating standar-dized wounds by the method of suction blister induction

C. Wagnera, A. Böhlinga, S. Bielfeldta and K.-P. Wilhelma,b

aproDERM Institut für Angewandte Dermatologische Forschung GmbH, Schenefeld/Hamburg, Deutschland und bUniversität zu Lübeck, Lübeck, Deutschland

BackgroundThe suction blister method is a well-established method of separating in vivo neatly the epidermis from the dermis without causing chemical or thermal da-mage. It is commonly used to sample biological material and to induce standardized epidermal wounds. The induction of fully developed blisters by applying a negative pressure of up to 40 kPa takes three to four hours on healthy skin of the volar forearms [1]. As this process is time consuming and therefore deman-ding for the subjects, an expectable time reduction of this process by increasing the applied negative pressure is of scientific interest. However there is the risk of quality loss by applying a higher pressure. Bursting of blisters or subcutaneous bleeding might occur. Therefore it is important to find the optimal balance between the negative pressure and the duration while maintaining high quality.

MethodsFour suction blisters were inducted with suction cups (Figure 1) on the volar forearms of 6 subjects with intact, healthy skin in the test area by SUCTION BLISTER SYSTEM (proDERM, Germany). The applied pressures were adjusted between 45 and 80 kPa with or without a 30 min lead time with a reduced pressure. The development and duration until the final shape of the blisters were docu-mented.

ResultsThe mean duration was between 88.5 ± 15.39 and 95 ± 17.72 min (Figure 2). The lead time did neither improve the quality of blisters (Figure 3, lower right image) nor reduced the time of induction.

ConclusionThis test provided evidence that an increase of negative pressure of more than 40 kPa reduced the time of formation while maintaining a consistent high level of blisters‘ quality. The induction time was reduced approximately by half when applying a negative pressure between 45 and 80 kPa. At pressures of 60 kPa and higher no further reduction of time to generate the blister was observed. Some more cases of erythema in the area of the blister and also around were noted with the ap-plied pressures of 45 kPA and higher but no increase of cases with blister rupture occurred. There were no advantages of a 30 min lead time with a low pressure of 35 kPa before setting the target value.We conclude that a negative pressure of 45 kPa is optimal to generate high quality blisters in about 90 minutes, a time which is clearly less demanding than an induction of blisters at 40 kPa or less. However, in case that blister fluid or blister roofs should be analyzed e.g. on parameters that could be influenced by a reaction of inflammation lower pressures or even a different method of sampling is recommended.

References1. Wilhelm et. al., 2017, „Models of wound healing: an emphasis on clinical studies“, Skin Res Technol, 23(1): 3-12

0

20

40

60

80

100

120

45 kPA 60 kPA 80 kPA 80 kPA*

Dura

tion

[min

]

45 kPA 60 kPA 80 kPA 80 kPA*

120

100

80

60

40

20

Dau

er [

min

]

0

45 kPa 60 kPa 80 kPa 80 kPa*