ABSTRACT
One of the effective ways to improve the productivity of mixed forests is enhancing resource use efficiency based on the biological characteristics of afforestation tree species. Resource use efficiency is affected by tree species interactions and environmental conditions through applying appropriate cultivation patterns. In this study, we evaluated two estimating methods for the productivity of mixed forest, analyzed the internal mechanism of interspecific tree competition and complementary effects on mixed forest productivity, clarified external factors of growth space and habitat factors control over productivity of mixed forest, discussed the effects of tree species composition, stand density and site quality on productivity, and illustrated the productivity trajectory during the development of mixed forests. Finally, based on the knowledge of the internal mechanism and habitat factors affecting the formation of mixed forest productivity, we focused on the key scientific issues that urgently need to be solved in the construction of the current mixed forests cultivation patterns, and put forward future research directions, including improving the productivity estimation system, establishing long-term mixed forest observation field, enhancing the research on the comprehensive effect of various cultivation measures, and reinforcing research of the growth and development dynamics in mixed forests.
Subject(s)
Forests , Trees , Ecosystem , EfficiencyABSTRACT
OBJECTIVES: To explore the etiology composition and outcomes of pediatric chronic critical illness (PCCI) in the pediatric intensive care unit (PICU). METHODS: The children who were hospitalized in the PICU of Dongguan Children's Hospital Affiliated to Guangdong Medical University and met the diagnostic criteria for PCCI from January 2017 to December 2022 were included in the study. The etiology of the children was classified based on their medical records and discharge diagnoses. Relevant clinical data during hospitalization were collected and analyzed. RESULTS: Among the 3 955 hospitalized children in the PICU from January 2017 to December 2022, 321 cases (8.12%) met the diagnostic criteria for PCCI. Among the 321 cases, the most common etiology was infection (71.3%, 229 cases), followed by unintentional injury (12.8%, 41 cases), postoperation (5.9%, 19 cases), tumors/immune system diseases (5.0%, 16 cases), and genetic and chromosomal diseases (5.0%, 16 cases). Among the 321 cases, 249 cases (77.6%) were discharged after improvement, 37 cases (11.5%) were discharged at the request of the family, and 35 cases (10.9%) died in the hospital. Among the deaths, infection accounted for 74% (26/35), unintentional injury accounted for 17% (6/35), tumors/immune system diseases accounted for 6% (2/35), and genetic and chromosomal diseases accounted for 3% (1/35). From 2017 to 2022, the proportion of PCCI in PICU diseases showed an increasing trend year by year (P<0.05). Among the 321 children with PCCI, there were 148 infants and young children (46.1%), 57 preschool children (17.8%), 54 school-aged children (16.8%), and 62 adolescents (19.3%), with the highest proportion in the infant and young children group (P<0.05). The in-hospital mortality rates of the four age groups were 14.9% (22/148), 8.8% (5/57), 5.6% (3/54), and 8.1% (5/62), respectively. The infant and young children group had the highest mortality rate, but there was no statistically significant difference among the four groups (P>0.05). CONCLUSIONS: The proportion of PCCI in PICU diseases is increasing, and the main causes are infection and unintentional injury. The most common cause of death in children with PCCI is infection. The PCCI patient population is mainly infants and young children, and the in-hospital mortality rate of infant and young children with PCCI is relatively high.
Subject(s)
Child, Hospitalized , Critical Illness , Adolescent , Infant , Child, Preschool , Humans , Child , Prognosis , Chronic Disease , Intensive Care Units, PediatricABSTRACT
OBJECTIVES: To study the clinical characteristics of ultrasound-guided central venous catheterization at various sites in infants with shock, and to explore how to quickly select the site for central venous puncture in infants with shock. METHODS: The medical data of 112 infants who were diagnosed with shock and underwent central venous catheterization in the Pediatric Intensive Care Unit, Dongguan Children's Hospital Affiliated to Guangdong Medical University, from January 2016 to December 2020 were reviewed retrospectively. The patients were divided into an ultrasound group (n=70) and a body surface location group (n=42) according to whether the catheterization was carried out under ultrasound guidance. The application of ultrasound-guided catheterization at various sites in infants was summarized and analyzed, and the success rate of one-time puncture, overall success rate, catheterization time, and complications were compared between these sites. RESULTS: Compared with the body surface location group, the ultrasound group had a significantly higher success rate of one-time puncture, a significantly shorter catheterization time, and a significantly reduced incidence rate of complications in internal jugular vein and femoral vein catheterizations (P<0.05). In the ultrasound group, the proportion of internal jugular vein catheterization was the highest (51%, 36/70), followed by femoral vein catheterization (33%, 23/70), and subclavian vein catheterization (16%, 11/70). For the comparison between different puncture sites under ultrasound guidance, internal jugular vein catheterization showed the shortest time of a successful catheterization [5.5 (5.0, 6.5) minutes] (P<0.05). There was no significant difference in the incidence rate of complications among the different puncture sites groups (P>0.05). CONCLUSIONS: In infants with shock, ultrasound-guided internal jugular vein catheterization can be used as the preferred catheterization method for clinicians.
