Non-invasive monitoring of carboxyhemoglobin during hyperbaric oxygen therapy.

Introduction: This study aimed to assess the capability of a pulse CO-oximeter to continuously monitor carboxyhemoglobin (COHb) during hyperbaric oxygen (HBO2) therapy. We estimated limits of agreement (LOA) between blood gas analysis and pulse CO-oximeter for COHb during HBO2 therapy in patients suffering from acute CO poisoning. Furthermore, we did a medicotechnical evaluation of the pulse CO-oximeter in hyperbaric conditions. Methods: We conducted a prospective, non-clinical, observational study in which we included n=10 patients with acute CO poisoning referred for HBO2 therapy. We did five repeated measurements of COHb for each patient during the HBO2 therapy. Bland-Altman analysis for multiple observations per individual was used to assess the agreement. The a priori LOA was ±6% for COHb. For the medicotechnical evaluation continuous measurements were obtained throughout each complete HBO2 therapy. The measurements were visually inspected and evaluated. Results: The Bland-Altman analysis showed that the pulse CO-oximeter overestimated COHb by 2.9 % [±1.0%] and the LOA was ±7.3% [±1.8%]. The continuous measurements by pulse CO-oximetry showed fluctuating levels of COHb and summarized saturations reached levels above 100%. Measurements were not affected by changes in pressure. Conclusion: To our knowledge, this study is the first to assess LOA and demonstrate use of a non-invasive method to measure COHb during HBO2 therapy. The pulse CO-oximeter performed within the manufactures reported LOA (±6%) despite hyperbaric conditions and was unaffected by changes in pressure. However, summarized saturations reached levels above 100%.

Long-Term Metastatic Risk after Biopsy of Posterior Uveal Melanoma.

PURPOSE: Biopsy of posterior uveal melanoma continues to be intensely debated in terms of the clinical benefits and safety profile. Although several studies have reported a low frequency of ocular complications after tumor biopsy, the potential long-term risk of iatrogenic dissemination remains unresolved. The purpose of this study was to assess the risk of metastatic disease after biopsy of posterior uveal melanoma. DESIGN: Retrospective nationwide cohort study linking clinical and histopathologic records to pathology, cancer, and mortality registries. PARTICIPANTS: All patients with posterior uveal melanoma treated in Denmark between January 1985 and December 2016. METHODS: For each patient, we recorded detailed information on age, gender, tumor characteristics, and diagnostic and therapeutic measures, including tumor biopsy, if any, and the primary treating hospital. Absolute risk of melanoma-specific death was presented by cumulative incidence curves that accounted for competing risks. Cox regression models were used to estimate crude and adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and melanoma-specific mortality of patients who underwent biopsy during primary treatment compared with nonbiopsied patients through November 1, 2017. Fine and Gray risk regression was used as a sensitivity analysis to evaluate the impact of competing risks. MAIN OUTCOME MEASURES: All-cause and melanoma-specific mortality. RESULTS: Among 1637 patients, 567 (35%) underwent biopsy during primary treatment. At diagnosis, biopsied patients exhibited better prognostic characteristics, including smaller tumor size (P < 0.001) and younger age (P < 0.001), than nonbiopsied patients. In the adjusted analyses, we observed no apparent differences in all-cause mortality (HR, 1.07; 95% CI, 0.89-1.26; P = 0.47) or melanoma-specific mortality (HR, 1.11; 95% CI, 0.89-1.39; P = 0.35) among biopsied patients compared with nonbiopsied patients. CONCLUSIONS: All-cause and melanoma-specific mortality after primary treatment were similar among biopsied and nonbiopsied patients with posterior uveal melanoma. Our findings do not support an increased metastatic risk after intraocular tumor biopsy.

The added value of perineal swabs when screening for asymptomatic methicillin-resistant Staphylococcus aureus colonization and risk factors for perineal carriage.

We examined the added value of perineal swabs in addition to nose and throat swabs when screening for Methicillin-resistant Staphylococcus aureus colonization, and risk factors for perineal carriage in 6,642 patients. In our mainly primary care setting, the added value was 9.3%. Patients <3 or ≥80 had the highest risk.

Posterior uveal melanoma incidence and survival by AJCC tumour size in a 70-year nationwide cohort.

PURPOSE: While early treatment of posterior uveal melanoma can save the eye, the effect of early treatment on survival remains unknown. Therefore, we aimed to determine whether the tumour size at diagnosis has changed over time, and if this has affected survival rates of patients with posterior uveal melanoma in Denmark. METHODS: Nationwide retrospective cohort study linking data from registry-based resources to data from clinical charts and pathology records. Including all Danish patients diagnosed with posterior uveal melanoma from 1943 to 2017. Incidence rates were estimated as annual percentage change (APC) overall and by American Joint Committee on Cancer (AJCC) tumour sizes. The age-period-cohort model was applied to estimate the relative risk of calendar period. The cox proportional hazards model, relative survival Kaplan-Meier curves and cumulative incidence curves were applied to estimate the effect of calendar period on survival. RESULTS: An overall increase in incidence rate of uveal melanoma was found (APC = 0.25%, 0.08-0.42; 95% CI). This was due to increasing incidence rate of AJCC T1 + T2 tumours (APC = 0.97%, 0.57-1.37; 95% CI), whereas no increase in incidence rates of AJCC T3 + T4 tumours was found (APC = -0.01%, -0.26 to 0.25; 95% CI). The disease-specific survival improved with calendar period for all tumour sizes (HR = 0.988; 0.984-0.993; 95% CI). CONCLUSION: Increasing incidence rate and improved survival rate for uveal melanoma was found concordantly with a decrease in tumour size during a 70-year period.

Measurement of peripheral arterial tonometry in patients with diabetic foot ulcers during courses of hyperbaric oxygen treatment.

INTRODUCTION: Treatment of diabetic foot ulcers is complex and often protracted. Hyperbaric oxygen treatment (HBOT) improves wound healing in diabetic ulcers and serves as an important adjunct to regular diabetic wound care. Endothelial dysfunction plays a central role in diabetes-related vascular complications and may be evaluated by a non-invasive technique called peripheral arterial tonometry which measures a reactive hyperaemia index (RHI). We hypothesized that endothelial function measured by peripheral arterial tonometry is impaired in diabetic foot ulcer patients and that HBOT might improve endothelial function. METHODS: Endothelial function was prospectively assessed by peripheral arterial tonometry in 22 subjects with diabetic foot ulcers and 17 subjects without diabetes during courses of HBOT. Endothelial function was evaluated before first (baseline) and 30th treatments, and at 90-day follow-up. Serum insulin growth factor-I (IGF-I) concentrations were determined by immunoassay. Results were compared to 23 healthy subjects. RESULTS: No baseline differences were found in endothelial function between subjects with diabetes, HBOT patients without-diabetes and healthy control subjects (RHI; 1.26, 1.61 and 1.81, respectively). No significant changes in RHI were found in patients with (P = 0.17) or without (P = 0.30) diabetes during courses of HBOT. At 90-day follow-up IGF-I was significantly reduced in the subjects with diabetes (P = 0.001) and unchanged in the group without diabetes (P = 0.99). CONCLUSIONS: We found no significant differences in RHI between subjects with diabetic foot ulcers and patients without diabetes, nor improvement in endothelial function assessed by peripheral arterial tonometry during courses of HBOT.

A single session of hyperbaric oxygen therapy demonstrates acute and long-lasting neuroplasticity effects in humans: a replicated, randomized controlled clinical trial.

PURPOSE: Animal studies have demonstrated anti-inflammatory, and anti-nociceptive properties of hyperbaric oxygen therapy (HBOT). However, physiological data are scarce in humans. In a recent experimental study, the authors used the burn injury (BI) model observing a decrease in secondary hyperalgesia areas (SHA) in the HBOT-group compared to a control-group. Surprisingly, a long-lasting neuroplasticity effect mitigating the BI-induced SHA-response was seen in the HBOT-preconditioned group. The objective of the present study, therefore, was to confirm our previous findings using an examiner-blinded, block-randomized, controlled, crossover study design. PATIENTS AND METHODS: Nineteen healthy subjects attended two BI-sessions with an inter-session interval of ≥28 days. The BIs were induced on the lower legs by a contact thermode (12.5 cm2, 47C°, 420 s). The subjects were block-randomized to receive HBOT (2.4 ATA, 100% O2, 90 min) or ambient conditions ([AC]; 1 ATA, 21% O2), dividing cohorts equally into two sequence allocations: HBOT-AC or AC-HBOT. All sensory assessments performed during baseline, BI, and post-intervention phases were at homologous time points irrespective of sequence allocation. The primary outcome was SHA, comparing interventions and sequence allocations. RESULTS: Data are mean (95% CI). During HBOT-sessions a mitigating effect on SHA was demonstrated compared to AC-sessions, ie, 18.8 (10.5-27.0) cm2 vs 32.0 (20.1-43.9) cm2 (P=0.021), respectively. In subjects allocated to the sequence AC-HBOT a significantly larger mean difference in SHA in the AC-session vs the HBOT-session was seen 25.0 (5.4-44.7) cm2 (P=0.019). In subjects allocated to the reverse sequence, HBOT-AC, no difference in SHA between sessions was observed (P=0.55), confirming a preconditioning, long-lasting (≥28 days) effect of HBOT. CONCLUSION: Our data demonstrate that a single HBOT-session compared to control is associated with both acute and long-lasting mitigating effects on BI-induced SHA, confirming central anti-inflammatory, neuroplasticity effects of hyperbaric oxygen therapy.