Objective To investigate the effect of electromagnetic wave power density on the expression of glial fibrillary acidic protein(GFAP)in the hippocampus of SD rats under 1800 MHz electromagnetic wave irradiation,and whether it exhibits a"window effect".Methods Ninety-eight 4-week-old SPF-grade SD rats were randomly divided into 14 groups,with 7 rats in each group.Seven groups were exposed groups(frequency:1800 MHz,power densities:0.1 mW/cm2,0.3 mW/cm2,0.5 mW/cm2,0.7 mW/cm2,0.9 mW/cm2,1.0 mW/cm2,1.2 mW/cm2)and corresponding 7 groups were control groups(power density:0 mW/cm2).Exposure was conducted for 12 hours daily for 3 weeks.After exposure,Western Blot was used to detect the expression level of GFAP in the hippocampal tissue,and immunohistochemistry staining was performed to determine the average optical density(MOD)value of GFAP-positive expression products in the DG,CA3,and CA1 regions of the hippocampal tissue,to determine the power density window of GFAP expression in the hippocampus of SD rats under 1800 MHz exposure.Results At power densities of 0.1 mW/cm2 and 0.3 mW/cm2,Western Blot results showed increased expression of GFAP in the rat hippocampus(P<0.05),and immunohistochemistry staining demonstrated increased MOD values of GFAP in the three regions(P<0.05).Conclusion Long-term exposure to 1800 MHz elect-romagnetic radiation has a"window effect"on the expression of GFAP in the DG,CA3,and CA1 regions of the hippocampus in SD rats,with power density windows of 0.1 mW/cm2 and 0.3 mW/cm2.

Objective:To explore a simple method for measuring the dynamic intrinsic positive end-expiratory pressure (PEEPi) during invasive mechanical ventilation.Methods:A 60-year-old male patient was admitted to the critical care medicine department of Dongying People's Hospital in September 2020. He underwent invasive mechanical ventilation treatment for respiratory failure due to head and chest trauma, and incomplete expiratory flow occurred during the treatment. The expiratory flow-time curve of this patient was served as the research object. The expiratory flow-time curve of the patient was observed, the start time of exhalation was taken as T 0, the time before the initiation of inspiratory action (inspiratory force) was taken as T 1, and the time when expiratory flow was reduced to zero by inspiratory drive (inspiratory force continued) was taken as T 2. Taking T 1 as the starting point, the follow-up tracing line was drawn according to the evolution trending of the natural expiratory curve before the T 1 point, until the expiratory flow reached to 0, which was called T 3 point. According to the time phase, the intrapulmonary pressure at the time just from expiratory to inspiratory (T 1 point) was called PEEPi 1. When the expiratory flow was reduced to 0 (T 2 point), the intrapulmonary pressure with the inhaling power being removed hypothetically was called PEEPi 2. And it was equal to positive end-expiratory pressure (PEEP) set in the ventilator at T 3 point. The area under the expiratory flow-time curve (expiratory volume) between T 0 and T 1 was called S 1. And it was S 2 between T 0 and T 2, S 3 between T 0 and T 3. After sedation, in the volume controlled ventilation mode, approximately one-third of the tidal volume was selected, and the static compliance of patient's respiratory system called "C" was measured using the inspiratory pause method. PEEPi 1 and PEEP 2 were calculated according to the formula "C =ΔV/ΔP". Here, ΔV was the change in alveolar volume during a certain period of time, and ΔP represented the change in intrapulmonary pressure during the same time period. This estimation method had obtained a National Invention Patent of China (ZL 2020 1 0391736.1). Results:① PEEPi 1: according to the formula "C =ΔV/ΔP", the expiratory volume span from T 1 to T 3 was "S 3-S 1", and the intrapulmonary pressure decreased span was "PEEPi 1-PEEP". So, C = (S 3-S 1)/(PEEPi 1-PEEP), PEEPi 1 = PEEP+(S 3-S 1)/C. ②PEEPi 2: the expiratory volume span from T 2 to T 3 was "S 3-S 2", and the intrapulmonary pressure decreased span was "PEEPi 2-PEEP". So, C = (S 3-S 2)/(PEEPi 2-PEEP), PEEPi 2 = PEEP+(S 3-S 2)/C. Conclusion:For patients with incomplete expiratory during invasive mechanical ventilation, the expiratory flow-time curve extension method can theoretically be used to estimate the dynamic PEEPi in real time.

A 82-year-old man was admitted to hospital with fever,unresponsiveness,elevated hypersensitive C-reactive protein and neutrophile granulocyte.Ceftriaxone was administrated by intravenous dripping in the emergency room,but the effect was not satisfactory.Following his admission to the ward,cefoperazone sulbactam were given.Elizabethkingia meningoseptica was identified by blood culture and further confirmed by 16S rRNA sequencing.The lumbar puncture showed that cerebrospinal fluid pressure was 80 mmH2O(1 mmH2O=0.0098 kPa)and biochemical results were normal.After 11 days of cefoperazone sulbactam treatment,the patient was discharged with negative blood culture.The hypersensitive C-reactive protein and neutrophile granulocyte had also declined.The patient received levofloxacin tablets for anti-infection treatment for 14 d after discharge.No signs of infection were observed in three months'following up.

OBJECTIVE: To find out the circuit pressure and flow at the trigger point by observing the characteristics of the inspiratory trigger waveform of the ventilator, confirm the intra-alveolar pressure as the index to reflect the effort of the trigger according to the working principle of the ventilator combined with the laws of respiratory mechanics, establish the related mathematical formula, and analyze its influencing factors and logical relationship. METHODS: A test-lung was connected to the circuit in a PB840 ventilator and a SV600 ventilator set in pressure-support mode. The positive end-expiratory pressure (PEEP) was set at 5 cmH₂O (1 cmH₂O ≈ 0.098 kPa), and the wall of test-lung was pulled outwards till an inspiratory was effectively triggered separately in slow, medium, fast power, and separately in flow-trigger mode (sensitivity V_Trig 3 L/min, 5 L/min) and pressure-trigger mode (sensitivity P_Trig 2 cmH₂O, 4 cmH₂O). By adjusting the scale of the curve in the ventilator display, the loop pressure and flow corresponding to the trigger point under different triggering conditions were observed. Taking intraalveolar pressure (Pa) as the research object, the Pa (called P_a-T) needed to reach the effective trigger time (T_T) was analyzed in the method of respiratory mechanics, and the amplitude of pressure change (ΔP) and the time span (ΔT) of Pa during triggering were also analyzed. RESULTS: (1) Corresponding relationship between pressure and flow rate at TT time: in flow-trigger mode, in slow, medium and fast trigger, the inhalation flow rate was V_Trig, and the circuit pressure was separately PEEP, PEEP-Pn, and PEEP-Pn' (Pn, Pn', being the decline range, and Pn' > Pn). In pressure-trigger mode, the inhalation flow rate was 1 L/min (PB840 ventilator) or 2 L/min (SV600 ventilator), and the circuit pressure was PEEP-P_Trig. (2) Calculation of P_a-T: in flow-trigger mode, in slow trigger: P_a-T = PEEP-V_TrigR (R represented airway resistance). In medium trigger: P_a-T = PEEP-Pn-V_TrigR. In fast trigger: P_a-T = PEEP-Pn'-V_TrigR. In pressure-trigger mode: P_a-T = PEEP-P_Trig-1R. (3) Calculation of ΔP: in flow trigger mode, in flow trigger: without intrinsic PEEP (PEEPi), ΔP = V_TrigR; with PEEPi, ΔP = PEEPi-PEEP+V_TrigR. In medium trigger: without PEEPi, ΔP = Pn+V_TrigR; with PEEPi, ΔP = PEEPi-PEEP+Pn+V_TrigR. In fast trigger: without PEEPi, ΔP = Pn'+V_TrigR; with PEEPi, ΔP = PEEPi-PEEP+Pn'+V_TrigR. In pressure-trigger mode, without PEEPi, ΔP = P_Trig+1R; with PEEPi, ΔP = PEEPi-PEEP+P_Trig+1R. (4) Pressure time change rate of Pa (F_P): F_P = ΔP/ΔT. In the same ΔP, the shorter the ΔT, the greater the triggering ability. Similarly, in the same ΔT, the bigger the ΔP, the greater the triggering ability. The FP could better reflect the patient's triggering ability. CONCLUSIONS The patient's inspiratory effort is reflected by three indicators: the minimum intrapulmonary pressure required for triggering, the pressure span of intrapulmonary pressure, and the pressure time change rate of intrapulmonary pressure, and formula is established, which can intuitively present the logical relationship between inspiratory trigger related factors and facilitate clinical analysis.
Humans ; Respiration, Artificial/methods* ; Positive-Pressure Respiration ; Lung ; Ventilators, Mechanical ; Respiratory Mechanics

Objective:To evaluate the clinical significance of our self-designed three-column scoring system for postoperative X-ray stability of intertrochanteric fracture after intramedullary nailing.Methods:A retrospective study was conducted of the 378 patients with intertrochanteric fracture who had been treated between January 2015 and June 2019 at Department of Orthopaedics, Linyi People's Hospital by internal fixation with proximal femoral nail antirotation (PFNA). They were 161 males and 217 females, aged from 60 to 97 years (average, 72.5 years). By the AO classification, there were 109 cases of type 31-A1, 188 cases of type 31-A2 and 81 cases of type 31-A3. Anteroposterior and lateral X-ray examinations of the hip were performed immediately after internal fixation to evaluate the fracture stability using our self-designed three-column scoring system by which the medial column is given 4 points, middle column 2 points and lateral column 2 points. A single column scoring full points is rated as stable, 3-column stability as excellent, 2-column stability as good, one-column stability as fair, and 3-column unstability as poor. Rehabilitation programs were carried out according to the results of stability evaluation: full weight bearing at an early stage was indicated for excellent patients, partial weight bearing at an early stage for good patients and weight bearing at an early stage contraindicated for fair or poor patients. Fracture union time and failure of internal fixation were recorded. The relationship between internal fixation failure and our three-column scoring system was calculated.Results:The 378 patients were followed up for 6 to 24 months (mean, 10.4 months). Of them, 365 obtained fracture union after an average time of 4.3 months (from 3 to 7 months). Internal fixation failure occurred in 13 patients, giving a failure rate of 3.4%(13/378).Of the 129 excellent patients by our three-column scoring system for post-operative X-ray stability of intertrochanteric fracture, none failed in internal fixation; of the 193 good patients, 4 failed; of the 56 fair patients, 9 failed. Internal fixation failure was closely related to our three-column scoring system for postoperative X-ray stability of intertrochanteric fracture ( r=-0.986, P=0.006), as well as to the column stability ( r=-1.000, P=0.033). Conclusion:Our self-designed three-column scoring system for postoperative X-ray stability of intertrochanteric fracture after intramedullary nailing can accurately reflect the fracture stability so that it can be used to guide rehabilitation programs for the patients and judge their prognosis.

As a non-physiological way of ventilation, mechanical ventilation has a great effect on the respiratory mechanics. The biggest problem of artificial airway is that it brings extra airway resistance to the respiratory tract. For different parts of the lung, positive pressure ventilation could cause different mechanic states. We can find the formation and influencing factors of transpulmonary pressure, transchest wall pressure, trans-lung-chest pressure, trans-diaphragmatic pressure, trans-pulmonary-diaphragmatic pressure, intrapleural pressure, plateau pressure and driving pressure, by analyzing the mechanic state in a unit area of the chest or diaphragm position in the way of basic mechanics. It is obviously different in the pulmonary pressure gradient caused by inspiratory driving between in spontaneous breathing and in mechanical ventilation. The pressure is transmitted from the periphery to the center in spontaneous breathing in physiological state, playing a traction role for lung tissue. The pressure is transmitted from the center to the periphery in positive pressure ventilation without spontaneous breathing, playing a pushing role for lung tissue. It can be divided into two stages in positive pressure ventilation with spontaneous breathing. The first stage is from inspiratory trigger effort to trigger sensitivity. It is similar to spontaneous inspiration in physiological state. The pressure gradient in this stage is from the peripheral to center. But the period is very short. The second stage is the positive pressure ventilation progress after the trigger sensitivity. The pressure gradient is caused by the pulling of the patient's spontaneous inhalation and the pushing of the positive pressure ventilation of the ventilator. There is a certain complementarity in the distribution and transmission of pressure, especially for non-physiological positive pressure ventilation. Therefore, through these basic mechanical analysis, clinical medical staff can better understand the impact of mechanical ventilation on respiratory mechanics.

Objective To design a mathematical calculation model for better understanding and grasping the logical problem of replacement fluid and citric acid anticoagulant infusion in continuous veno-venous hemofiltration (CVVH). Methods ① Parameter definition: A, B, and T were respectively called the main part of pre-replacement fluid, 5% sodium bicarbonate solution, and 4% sodium citrate infused before filter. And a and b were respectively called the main part of post-replacement fluid, and 5% sodium bicarbonate solution infused after filter. ② Logic conversion:The liquid in back terminal (Z) was artificially divided into two parts. One (X) was the original residual plasma after filtration. The second (Y) was the part excluding the plasma, including the left part of pre-replacement fluid with sodium citrate, and the post-replacement fluid. ③The mathematical formulas of liquid volume and electrolyte concentration at X, Y and Z in unit time were listed according to the principle of CVVH and the screening coefficient of filter for different substances. ④The calculation formulas were entered into Excel form, and a mathematical calculation model was made, and a simulation calculation with examples was carried out. Results An Excel model was established by inserting the calculation formulas of volume, electrolyte, and total calcium at X, Y and Z. And it was found that the concentration of Na+, K+, Cl-, HCO3- at Y point remained unchanged only when A, B and (or) a, b was kept in same side and proportion even with the change of blood flow and other parameters without sodium citrate as anticoagulant. Once any of the parameters (such as blood flow, replacement fluid volume, etc.) were adjusted in other infusion methods (such as different ratios, different directions of the same year, etc.), the calculation results at Y would vary, and the electrolyte concentration at Z would change accordingly. A change of dilution model or parameter would result in the change of the electrolyte concentration at Y and Z with sodium citrate as anticoagulant. The concentration of total calcium scarcely changed no matter in what model and parameters. Conclusions All kinds of infusion ways could be included in the Excel model. The infusion results of all kinds of infusion matching could be intuitively evaluated. It is helpful for the medical staff to make a logical analysis and risk prediction in CVVH.

Objective? To? analyze? the? ineffective? triggering? caused? by? nebulization? in? the? way? of?respiratory?mechanics.? Methods? A?test-lung?and?an?oxygen-driven?jet?nebulizer?were?connected?to?the?circuit?in?a?PB840?ventilator.?The?test-lung?was?pulled?outwards?in?manual?way?till?an?inspiration?was?effectively?triggered?separately?in?different?flow-trigger?modes?[flow-trigger?sensitivity?(VTrig)?3?L/min?and?5?L/min]?and?pressure-trigger?modes?[pressure-trigger?sensitivity?(PTrig)?2?cmH2O?and?4?cmH2O,?1?cmH2O?=?0.098?kPa]?with?the?nebulizer?being?closed?and?opened?in?turn.?The?corresponding?relationship?and?characteristics?between?the?flow?and?pressure?in?the?circuit?under?different?triggering?conditions?were?observed?by?adjusting?the?curve?amplitude?in?the?screen.?The?minimum?alveolar?pressure?(Pa)?which?could?cause?an?effective?triggering?and?the?variation?span?of?Pa?during?the?triggering?period?were?analyzed?in?respiratory?mechanics.? Results? ①?In?flow-trigger?mode:?Pa?was?pulled?down? from? positive? end-expiratory? pressure? (PEEP)? or? intrinsic? positive? end-expiratory? pressure? (PEEPi)? to?"PEEP－VTrigR"?(R?meant?airway?resistance)?without?nebulization,?and?the?span?of?Pa?was?"VTrigR"?or?"PEEPi－PEEP+VTrigR".?Pa?was?pulled?down?from?PEEP?or?PEEPi?to?"PEEP－(VTrig+N)?R"?(N?meant?nebulization?airflow)?with?nebulization,?and?the?span?of?Pa?was?"(VTrig+N)?R"?or?"PEEPi－PEEP+(VTrig+N)?R".?②?In?pressure-trigger?mode:?Pa?was?pulled?down?from?PEEP?or?PEEPi?to?"PEEP－PTrig－1R"?without?nebulization,?and?the?span?of?Pa?was?"PTrig+1R"?or?"PEEPi－PEEP+PTrig+1R".?Pa?was?pulled?down?from?PEEP?or?PEEPi?to?"PEEP－PTrig－(N+1)?R"?with?nebulization,?and?the?span?of?Pa?was?"PTrig+(N+1)?R"?or?"PEEPi－PEEP+PTrig+(N+1)?R".? ?Conclusions? Nebulization?airflow?increases?the?difficulty?of?inspiratory?triggering?in?mechanical?ventilation.?PEEPi?makes?it?more?difficult.

Objective: To better understand the significance of the pressure-time curve and flow-time curve from the perspective of PB840 ventilator working principle. Methods: ① Mechanical principle: flow supply valves (air valve and oxygen valve) and exhalation valve in PB840 ventilator were controlled to achieve the ventilation target (volume or pressure) by the central processing unit according to the monitoring data from pressure sensors (P₁ at the supply side, P₂ at the exhalation side) and flow sensors (Q₁ at the air side, Q₂ at the oxygen side, Q₃ at the exhalation side). ② The essence of curve: each point means a value of pressure or flow at a certain time measured by the sensors or calculated by the system. ③ The respiratory process could be divided into inspiratory part, expiratory part, and the connection part from expiratory to inspiratory. The air running state and the respiratory mechanics relationship at the three parts could be inferred according to the form of curves. Results: ① Inspiratory process: at volume-controlled and constant flow ventilation: there should be a relationship "Pc-Pa = XR" between alveolar pressure (Pa) and circuit pressure (Pc) according to Ohm law. So, the Pc curve (pressure-time curve) could indirectly reflect the Pa curve with the flow (X) and resistance (R) being constant. At pressure-set ventilation: it is the goal of ventilator to maintain the Pc at the target level. So, the stability of the target pressure line in pressure-time curve reflects the matching ability of the flow supply valves and the exhalation valve. ② Expiratory process: it could be divided into pre-expiratory [without basic flow (Ba) or bias flow (Bi)] and post-expiratory (with Ba or Bi), where Ba or Bi is equal to "Q₁+Q₂". So, the mathematical function are "X(t) = Q₃t" in pre-part, and "X(t) = Q₃t-(Q₁t+Q₂t)" in post-part. The relationship between pressure and flow at peak expiratory flow point: it could be found that there is an obvious time span and area formation under the curve from 0 to peak point (Fpeak) after stretching the abscissa axis of flow-time curve. It means that some gas have been discharged from the lung when it arrives at the peak point. So, the alveolar pressure should be lower than the platform pressure at the point (Pplat). The circuit pressure is significantly higher than positive end expiratory pressure (PEEP) at the point in the stretching axis diagram. So, it means that the formula "R_E = (Pplat-PEEP)/Fpeak" to calculate the expiratory resistance (R_E) is unreasonable in the angle of Ohm law. ③ The process from exhalation to inspiratory: according to the difference of the starting point of the conversion, it could be divided into two cases: one is that the inspiratory started from the ending of exhalation. Here, the inhaling starting point is lying in the abscissa axis. The other is that the inspiratory started before the ending of exhalation (with endogenous positive end expiratory pressure). Here, the starting point is lying below the abscissa axis, and the slope of the following curve is obviously larger than the slope of natural expiratory curve. According to the difference of results from the starting point to the end of the inhalation triggering effort, it could be divided into two cases: one is that it reach the trigger point. Here, the expiratory curve extends upward from or below the horizontal axis until an effective air supply is triggered. The other is that it could not reach the trigger point. Here, the expiratory curve extends upward from or below the horizontal axis, but then runs downward (meaning exhaling). Conclusion It is helpful to analyze the ventilation state, ventilation failure, and the causes of man-machine confrontation with understanding the ventilation principle and the air route map of the ventilator.

OBJECTIVE: To better understand the significance of the pressure-time curve and flow-time curve from the perspective of PB840 ventilator working principle. METHODS: (1) Mechanical principle: flow supply valves (air valve and oxygen valve) and exhalation valve in PB840 ventilator were controlled to achieve the ventilation target (volume or pressure) by the central processing unit according to the monitoring data from pressure sensors (P₁ at the supply side, P₂ at the exhalation side) and flow sensors (Q₁ at the air side, Q₂ at the oxygen side, Q₃ at the exhalation side). (2) The essence of curve: each point means a value of pressure or flow at a certain time measured by the sensors or calculated by the system. (3) The respiratory process could be divided into inspiratory part, expiratory part, and the connection part from expiratory to inspiratory. The air running state and the respiratory mechanics relationship at the three parts could be inferred according to the form of curves. RESULTS: (1) Inspiratory process: at volume-controlled and constant flow ventilation: there should be a relationship "Pc-Pa = XR" between alveolar pressure (Pa) and circuit pressure (Pc) according to Ohm law. So, the Pc curve (pressure-time curve) could indirectly reflect the Pa curve with the flow (X) and resistance (R) being constant. At pressure-set ventilation: it is the goal of ventilator to maintain the Pc at the target level. So, the stability of the target pressure line in pressure-time curve reflects the matching ability of the flow supply valves and the exhalation valve. (2) Expiratory process: it could be divided into pre-expiratory [without basic flow (Ba) or bias flow (Bi)] and post-expiratory (with Ba or Bi), where Ba or Bi is equal to "Q₁+Q₂". So, the mathematical function are "X(t) = Q_3t" in pre-part, and "X(t) = Q_3t-(Q_1t+Q_2t)" in post-part. The relationship between pressure and flow at peak expiratory flow point: it could be found that there is an obvious time span and area formation under the curve from 0 to peak point (Fpeak) after stretching the abscissa axis of flow-time curve. It means that some gas have been discharged from the lung when it arrives at the peak point. So, the alveolar pressure should be lower than the platform pressure at the point (Pplat). The circuit pressure is significantly higher than positive end expiratory pressure (PEEP) at the point in the stretching axis diagram. So, it means that the formula "R_E = (Pplat-PEEP)/Fpeak" to calculate the expiratory resistance (_E) is unreasonable in the angle of Ohm law. (3) The process from exhalation to inspiratory: according to the difference of the starting point of the conversion, it could be divided into two cases: one is that the inspiratory started from the ending of exhalation. Here, the inhaling starting point is lying in the abscissa axis. The other is that the inspiratory started before the ending of exhalation (with endogenous positive end expiratory pressure). Here, the starting point is lying below the abscissa axis, and the slope of the following curve is obviously larger than the slope of natural expiratory curve. According to the difference of results from the starting point to the end of the inhalation triggering effort, it could be divided into two cases: one is that it reach the trigger point. Here, the expiratory curve extends upward from or below the horizontal axis until an effective air supply is triggered. The other is that it could not reach the trigger point. Here, the expiratory curve extends upward from or below the horizontal axis, but then runs downward (meaning exhaling). CONCLUSIONS It is helpful to analyze the ventilation state, ventilation failure, and the causes of man-machine confrontation with understanding the ventilation principle and the air route map of the ventilator.
Exhalation ; Humans ; Positive-Pressure Respiration ; Respiration, Artificial ; Respiratory Insufficiency ; Respiratory Mechanics ; Ventilators, Mechanical