The emerging role of AMPK in the regulation of breathing and oxygen supply

Regulation of breathing is critical to our capacity to accommodate deficits in oxygen availability and demand during, for example, sleep and ascent to altitude. It is generally accepted that a fall in arterial oxygen increases afferent discharge from the carotid bodies to the brainstem and thus delivers increased ventilatory drive, which restores oxygen supply and protects against hypoventilation and apnoea. However, the precise molecular mechanisms involved remain unclear. We recently identified as critical to this process the AMP-activated protein kinase (AMPK), which is key to the cell-autonomous regulation of metabolic homoeostasis. This observation is significant for many reasons, not least because recent studies suggest that the gene for the AMPK-α1 catalytic subunit has been subjected to natural selection in high-altitude populations. It would appear, therefore, that evolutionary pressures have led to AMPK being utilized to regulate oxygen delivery and thus energy supply to the body in the short, medium and longer term. Contrary to current consensus, however, our findings suggest that AMPK regulates ventilation at the level of the caudal brainstem, even when afferent input responses from the carotid body are normal. We therefore hypothesize that AMPK integrates local hypoxic stress at defined loci within the brainstem respiratory network with an index of peripheral hypoxic status, namely afferent chemosensory inputs. Allied to this, AMPK is critical to the control of hypoxic pulmonary vasoconstriction and thus ventilation–perfusion matching at the lungs and may also determine oxygen supply to the foetus by, for example, modulating utero-placental blood flow

Timing of central venous catheter exchange and frequency of bacteremia in burn patients

We evaluated the impact of increasing the interval between routine central venous catheter exchanges from every 3 days to every 4 days on the rate of catheter infections and catheter-related bacteremia. Computer records of catheter tip and blood culture results in burn patients were reviewed. The change to every 4 day catheter exchange occurred in November 2000 and data were collected until June 2001. One hundred and ninety-six guidewire exchanges were performed in the every 3 day (q3day) group, and 164 guidewire exchanges were performed in the every 4 day (q4day) group. The rate of catheter infections (>15 colony forming units) was 11% in the q3day group and 28% in the q4day group. Catheter-related blood stream infection occurred in 4% of patients in q3day group and 12% of patients in q4day group. A prospective review of this change in practice revealed that there was a significantly greater risk of infections in the q4day group. The increase in infected central venous catheter segments was associated with an increase in blood stream infections

Tracking non-burn center care: what you don't know may surprise you

The American Burn Association publishes a list of defined criteria for patients who require admission or transfer to a burn center. This study examines the extent to which those criteria are observed within a regional burn network. Hospital discharge data for 2008 were obtained for all hospitals within the South Florida regional burn network. Patients with International Classification of Diseases, 9th revision discharge diagnoses for burns were reviewed, and their triage destination was compared with the burn triage referral criteria to determine whether patients were inappropriately triaged. Descriptive statistics were used to analyze the data. Four hundred ninety-eight burn admissions were documented to non-burn center center hospitals, 269 (54%) of which were deemed inappropriate by burn triage referral criteria. Burn center patients had greater length of stay when compared with non-burn center patients (14 vs 7 days), but a greater percentage were discharged home for self-care (88 vs 57%). Thirty-three percent of the inappropriate admissions were in a neighboring county, whereas 27% were in the same county where the burn center is located. Inappropriate burn patient triage may be occurring to more than half of the burn patients within our regional burn network despite better functional outcomes at the burn center. This may be because of a lack of knowledge regarding triage criteria, patient insurance status, or other factors. Further studies are necessary to fully characterize the problem and implement education or incentives to encourage appropriate burn patient triage

A prospective, randomized trial of Acticoat versus silver sulfadiazine in the treatment of partial-thickness burns: which method is less painful?

Despite recent improvements in analgesia, pain control during dressing changes continues to be a major challenge in patients with burns. We investigated two different dressing modalities to compare how much pain the patient experienced during and after the dressing change. Patients with partial-thickness burns that required only topical wound care were assigned randomly to treatment with Acticoat (Smith and Nephew USA, Largo, FL) or silver sulfadiazine (AgSD). The outcome variable was pain during wound care, which was measured using visual analog pain scores. The mean visual analog pain scores for the wounds treated with Acticoat or AgSD wounds were 3.2 and 7.9, respectively (P < .0001; paired Student's t-test). In 41 of the 47 paired pain score observations, the pain in the wound treated with AgSD was perceived as greater than in the wound treated with Acticoat. Burn wound care with Acticoat is less painful than burn wound care with AgSD in patients with selected partial-thickness burns

The impact of caregiver support on mortality following burn injury in the elderly

Advances in burn care have decreased mortality in the past 20 years, but affecting elderly mortality rates (>65 years) remain challenging. This study evaluates the impact of home caregiver support on elderly burn patients' mortality. The authors retrospectively reviewed patients aged 65 and older admitted to their burn center from July 1995 to October 2004. Patient demographics, Injury Severity Score, TBSA, and patients' primary caregiver were collected. The outcomes were mortality, disposition, and length of stay and these were evaluated using univariate and subsequently multivariate regression. Significance was calculated at P ≤ .05. A total of 112 patients were included in the analysis. The mean age was 76±8. Male patients constituted 47%, whereas 53% were female patients, and mean TBSA was 21±16%. Thirty patients' primary caregiver was a spouse, for 38 it was a child, and 44 had no caregiver. Fifty-eight patients survived (51.7%), and 54 patients died (48.3%). Only 21% of the survivors had a child as their primary caregiver; however, 48% of the nonsurvivors had a child as the primary caregiver (P ≤ 0.05). On multivariate analysis, age, TBSA, and child as primary caregiver were all independent predictors of mortality. Having a child as a caregiver provided the largest impact, with an odds ratio of 4.4 (95% confidence interval, 1.2-15.62; P = .02)

Scald Burns From Hair Braiding

Only one previous case report has described scald burns secondary to hair braiding in pediatric patients. The present case study is the largest to date of scald burns as a result of hair braiding in children and adults. Charts of all 1609 female patients seen at a single burn center from 2008 to 2014 were retrospectively reviewed to identify patients with scald burns attributed to hair braiding. Demographics, injury severity, injury patterns, and complications were analyzed. Twenty-six patients (1.6%) had scald burns secondary to hair braiding with median TBSA 3%. Eighty-five percent of patients were pediatric with median age 8 years. Injury patterns were as follows: back (62%), shoulder (31%), chest (15%), buttocks (15%), abdomen (12%), arms (12%), neck (12%), and legs (4%). No patients required operative intervention. Three patients were admitted to the hospital. Two patients required time off from school for 6 and 10 days post burn for recovery. Complications included functional limitations (n = 2), hypertrophic scarring (n = 1), cellulitis requiring antibiotics (n = 1), and anxiety requiring medical/psychological therapy (n = 2). This peculiar mechanism of injury not only carries inherent morbidity that includes the risks of functional limitations, infection, and psychological repercussions but also increases usage of resources through hospital admissions and multiple clinic visits. Further work in the form of targeted outreach programs is necessary to educate the community regarding this preventable mechanism of injury