Associations Among Skin Surface pH, Temperature, and Bacterial Burden in Wounds

Use of Infrared Thermometry to Observe Temperature Variation Associated with the Healing Process in Wounds and Ulcers: TIHUAP Cohort Study Protocol

We are interested in observing how temperature differences between the wound bed and perilesional skin are related to the healing process in primary care patients with wounds. Multisite prospective cohort study with one-year follow-up in the Metropolitan North area of Barcelona. Recruitment of patients over 18 years with an open wound will take place from January 2023 to September 2023. Temperature checks will be conducted on a weekly basis at control visits and wound care. The following variables will be measured: Percentage reduction of wound area over time, thermal index, the Kundin Wound Gauge, and the Resvech 2.0 Scale. The temperature will be measured weekly using a handheld thermometer and mesh grid to frame the temperature points. The healing trajectory will also be monitored on a monthly basis via photographic imaging, the Resvech Scale, calculation of wound size, percentage reduction of wound area over time, and thermal index for one year of follow-up or until the wound is cured. This study may represent a turning point for its introduction into primary care. Early diagnosis of wound complications would facilitate treatment decision-making for healthcare professionals, thus improving the management of resources related to chronic wounds.

Wound pH and temperature as predictors of healing: an observational study

OBJECTIVE

The aim of this study was to measure wound pH, wound temperature and wound size together to gain further understanding of their impact as predictors of wound healing outcomes.

METHOD

This study employed a quantitative non-comparative, prospective, descriptive observational design. Participants with both acute and hard-to-heal (chronic) wounds were observed weekly for four weeks. Wound pH was measured using pH indicator strips, wound temperature was measured using an infrared camera and wound size was measured using the ruler method.

RESULTS

Most of the 97 participants (65%, n=63) were male; participant's ages ranged between 18 and 77 years (mean: 42±17.10. Most of the wounds observed were surgical 60%, (n=58) and 72% (n=70) of the wounds were classified as acute, with 28% (n=27) classified as hard-to-heal wounds. At baseline, there was no significant difference in pH between acute and hard-to-heal wounds; overall the mean pH was 8.34±0.32, mean temperature was 32.86±1.78°C) and mean wound area was 910.50±1132.30mm2. In week 4, mean pH was 7.71±1.11, mean temperature was 31.90±1.76°C and mean wound area was 339.90±511.70mm2. Over the study follow-up period, wound pH ranged from 5-9, from week 1 to week 4, mean pH reduced by 0.63 units from 8.34 to 7.71. Furthermore, there was a mean 3% reduction in wound temperature and a mean 62% reduction in wound size.

CONCLUSION

The study demonstrated that a reduction in pH and temperature was associated with increased wound healing as evidenced by a corresponding reduction in wound size. Thus, measuring pH and temperature in clinical practice may provide clinically meaningful data pertaining to wound status.

A time-dependent survival analysis for early prognosis of chronic wounds by monitoring wound alkalinity

The objective is to determine whether monitoring wound alkalinity between visits may help prognosticate chronic wound healing. The alkalinity of 167 wounds during the first 3 visits was assessed using disposable DETEC® pH. Wounds grouped by frequency of alkaline results were compared by % wound size reduction during each visit and 120-day healing probability. The Cox proportional hazards model for time-dependent variables was used to generate non-healing probability curves, where variables are binary (alkaline/non-alkaline, infection/no infection), categorical (wound type), and continuous (wound area); the response is time to complete wound healing; and the event of interest is complete wound healing in 120 days. Results show that wounds with frequent alkaline results have significantly smaller % size reduction per visit. Logistic regression shows an increase in 120-day healing probability with fewer alkaline results. Survival analysis shows that the instantaneous healing rate of non-alkaline or non-alkaline transitioning wounds is 1.785, 2.925, and 5.908 times that of alkaline or alkaline-transitioning wounds for 1, 2, and 3 alkalinity measurements, respectively. Furthermore, the concordance statistic of each survival model shows that goodness of fit increases with more alkalinity measurements. Overall, frequent wound alkalinity assessments may serve as a novel way to prognosticate wound healing outcomes.

A wound alkalinity measurement to predict non-healing wound outcomes

Objective:

As wound pH could influence wound healing rates, this study examined the alkalinity of the entire wound during patients' follow-up visits to predict the final non-healing outcome.

Method:

Wound alkalinity of patients with diabetic foot ulcers (DFUs), venous leg ulcers, and other wounds during three follow-up visits within a four week period was recorded. All wounds were followed until 12 weeks to confirm that healed wounds did not relapse. The alkalinity of various wounds over multiple visits with varying durations was compared with final wound status to assess whether one-time wound alkalinity measurement could predict non-healing wounds. The effect of wound types, infection, age and sex on such determinations was also studied.

Results:

A total of 96 patients were included in this study. Based on probability variations of pre- and post-test non-healing outcomes from multiple visits over 12 weeks, second visit assessment gave the highest increase in risk of non-healing for an alkaline test result (+8.0%) and decrease in risk of non-healing for a non-alkaline test result (–19.7%). Moreover, a second visit (7–21 days from first visit) showed a greater change in risk for non-healing based on alkaline and non-alkaline test results (+15.7% and –38.1% respectively), compared with a visit within seven days (+6.3% and –12.5%, respectively). Wound type, infection, age and sex did not affect the prognostic ability of wound alkalinity.

Conclusion:

The results of this study support that a single wound alkalinity measurement during the second visit (7–21 days from first visit) can be used to predict non-healing wounds. Wound alkalinity may be routinely assessed to predict non-healing wounds and to determine whether the wounds are healing as expected following initial treatment.

Does pH Influence the Bacterial Profile of Chronic Lesions? An Analysis of Venous Ulcer Samples

OBJECTIVE

To analyze the pH of venous ulcers and their relationship with the quantitative and qualitative bacterial profile of the wounds.

METHODS

Cross-sectional study carried out through data collection and microbiologic analyses of samples obtained from 35 venous ulcers. Investigators performed pH measurement with indicator strips and collected biologic material using swabs. After aerobic and anaerobic cultivation, colony-forming units (CFUs) were counted and used for bacterial identification via mass spectrometry.

RESULTS

The pH values ranged from 7.9 to 8.7; 8.5 (37.1%) was the most frequent, followed by 8.3 (28.6%). The most common species were Staphylococcus aureus (68.6%), Pseudomonas aeruginosa (62.9%), Proteus mirabilis (45.7%), and Corynebacterium striatum (40.0%). The number of CFUs ranged from 0 to 200,000 in both anaerobiosis and aerobiosis and was predominantly between 1,000 and 10,000 (37.1%) in anaerobiosis and between 10,000 and 100,000 (37.1%) in aerobiosis. No association was found between the different pH values and the variation in CFUs in anaerobiosis (P = .21) and aerobiosis (P = .55) or by bacterial species identified: S aureus (P = .41), P aeruginosa (P = .29), P mirabilis (P = .19), and C striatum (P = .96).

CONCLUSIONS

The pH of venous ulcers did not influence bacterial profile in quantitative or qualitative parameters.

Wound infection: A review of qualitative and quantitative assessment modalities

Surgical site infections (SSI) and chronic wounds represent a burden to patients and the health care system. One in 24 surgical patients will develop an SSI, making SSI the most common nosocomial infection in the USA. Early detection and monitoring of wound infection are critical for timely healing and return to normal function. However, the mainstay of wound infection diagnostic entails subjective clinical examination and semi-quantitative, invasive microbiological tests. In this review, we present current wound infection assessment modalities in the clinical and translational fields. There is a need for a point-of-care assessment tool that provides fast, accurate, and quantitative information on wound status, with minimal to no contact with the patient. In the next ten years, the evolution of wound diagnostic tools reported here may allow medical providers to optimize patient care while minimizing patient discomfort.

Lactic acid as a major contributor to hand surface infection barrier and its association with morbidity to infectious disease

Although the surface of the human hands contains high antimicrobial activity, studies investigating the precise components involved and the relationship between natural antimicrobial activity and morbidity in infectious diseases are limited. In this study, we developed a method to quantitatively measure the antimicrobial activity of hand surface components. Using a clinical survey, we validated the feasibility of our method and identified antimicrobial factors on the surface of the human hand. In a retrospective observational study, we compared the medical histories of the participants to assess infectious diseases. We found that the antimicrobial activity on the surface of the hands was significantly lower in the high morbidity group (N = 55) than in the low morbidity group (N = 54), indicating a positive association with the history of infection in individuals. A comprehensive analysis of the hand surface components indicated that organic acids, especially lactic acid and antimicrobial peptides, are highly correlated with antimicrobial activity. Moreover, the application of lactic acid using the amount present on the surface of the hand significantly improved the antimicrobial activity. These findings suggest that hand hygiene must be improved to enhance natural antimicrobial activity on the surface of the hands.