Comparison of Complication Rates Between Subpectoral vs Prepectoral Techniques in Prosthetic Breast Reconstruction.

BACKGROUND: The location of tissue expanders in implant-based breast reconstruction remains controversial due to variation in surgical techniques and devices. OBJECTIVES: The aim of this study was to provide a comprehensive assessment of early and late complication rates between prepectoral and subpectoral placement of tissue expanders. METHODS: A retrospective cohort study was conducted of all adult female patients who had undergone 2-stage implant-based breast reconstruction between 2013 and 2019 in our institution. Early complication was defined as complications that occurred within 30 days after surgery. Time-to-event analyses were performed and Cox proportional hazard models were used to adjust for confounders. RESULTS: In total, 854 patients were included; 76% of patients underwent a subpectoral tissue expander placement. After the first-stage procedure, the early complication rate was 34% and the late complication rate was 36.4%. After the second-stage procedure, the early complication rate was 16.3% and the late complication rate was 16.1%. Location of the tissue expander did not predict either overall early or late complication rates, regardless of the stages of reconstruction, after adjusting for confounders. Tissue expanders placed in prepectoral plane were associated with a higher hazard ratio (HR) for developing early and late infection after the first stage of reconstruction (HR, 2.1 and 2.4, respectively) as well as late infection after the second stage of reconstruction (HR, 5.3; all P < .05). CONCLUSIONS: Location of tissue expanders did not predict risk of complication. However, the prepectoral group was associated with an increased risk of developing infection.

Neurological Examination Frequency and Time-to-Delirium After Traumatic Brain Injury.

BACKGROUND: Frequent neurological examinations in patients with traumatic brain injury (TBI) disrupt sleep-wake cycles and potentially contribute to the development of delirium. OBJECTIVE: To evaluate the risk of delirium among patients with TBI with respect to their neuro-check frequencies. METHODS: A retrospective study of patients presenting with TBI at a single level I trauma center between January 2018 and December 2019. The primary exposure was the frequency of neurological examinations (neuro-checks) assigned at the time of admission. Patients admitted with hourly (Q1) neuro-check frequencies were compared with those who received examinations every 2 (Q2) or 4 (Q4) hours. The primary outcomes were delirium and time-to-delirium. The onset of delirium was defined as the first documented positive Confusion Assessment Method for the Intensive Care Unit score. RESULTS: Of 1552 patients with TBI, 458 (29.5%) patients experienced delirium during their hospital stay. The median time-to-delirium was 1.8 days (IQR: 1.1, 2.9). Kaplan-Meier analysis demonstrated that patients assigned Q1 neuro-checks had the greatest rate of delirium compared with the patients with Q2 and Q4 neuro-checks ( P < .001). Multivariable Cox regression modeling demonstrated that Q2 neuro-checks (hazard ratio: 0.439, 95% CI: 0.33-0.58) and Q4 neuro-checks (hazard ratio: 0.48, 95% CI: 0.34-0.68) were protective against the development of delirium compared with Q1. Other risk factors for developing delirium included pre-existing dementia, tobacco use, lower Glasgow Coma Scale score, higher injury severity score, and certain hemorrhage patterns. CONCLUSION: Patients with more frequent neuro-checks had a higher risk of developing delirium compared with those with less frequent neuro-checks.

Prebiotic condensation through wet-dry cycling regulated by deliquescence.

Wet-dry cycling is widely regarded as a means of driving condensation reactions under prebiotic conditions to generate mixtures of prospective biopolymers. A criticism of this model is its reliance on unpredictable rehydration events, like rainstorms. Here, we report the ability of deliquescent minerals to mediate the oligomerization of glycine during iterative wet-dry cycles. The reaction mixtures evaporate to dryness at high temperatures and spontaneously reacquire water vapor to form aqueous solutions at low temperatures. Deliquescent mixtures can foster yields of oligomerization over ten-fold higher than non-deliquescent controls. The deliquescent mixtures tightly regulate their moisture content, which is crucial, as too little water precludes dissolution of the reactants while too much water favors hydrolysis over condensation. The model also suggests a potential reason why life evolved to favor the enrichment of potassium: so living systems could acquire and retain sufficient water to serve as a solvent for biochemical reactions.