Neurocritical care (NCC) is not only generally guided by principles of general intensive care, but also directed by specific goals and methods. This review summarizes the common pulmonary diseases and pathophysiology affecting NCC patients and the progress made in strategies of respiratory support in NCC. This review highlights the possible interactions and pathways that have been revealed between neurological injuries and respiratory diseases, including the catecholamine pathway, systemic inflammatory reactions, adrenergic hypersensitivity, and dopaminergic signaling. Pulmonary complications of neurocritical patients include pneumonia, neurological pulmonary edema, and respiratory distress. Specific aspects of respiratory management include prioritizing the protection of the brain, and the goal of respiratory management is to avoid inappropriate blood gas composition levels and intracranial hypertension. Compared with the traditional mode of protective mechanical ventilation with low tidal volume (Vt), high positive end-expiratory pressure (PEEP), and recruitment maneuvers, low PEEP might yield a potential benefit in closing and protecting the lung tissue. Multimodal neuromonitoring can ensure the safety of respiratory maneuvers in clinical and scientific practice. Future studies are required to develop guidelines for respiratory management in NCC.
Humans ; Lung ; Lung Diseases/etiology* ; Positive-Pressure Respiration/methods* ; Respiration, Artificial/adverse effects* ; Tidal Volume

The high frequency oscillatory ventilation (HFOV) is characterized with low tidal volume and low mean airway pressure, and can well support the breathing of the patients with respiratory diseases. Since the HFOV was proposed, it has been widely concerned by medical and scientific researchers. About the HFOV, this paper discussed its current research status and prospected its future development in technologies. The research status of ventilation model, mechanisms and ventilation mode were introduced in detail. In the next years, the technologies in developing HFOV will be focused on: to develop the branched high-order nonlinear or volume-depended resistance-inertance-compliance (RIC) ventilation model, to fully understand the mechanisms of HFOV and to achieve the noninvasive HFOV. The development in technologies of HFOV will be beneficial to the patients with respiratory diseases who failed with conventional mechanical ventilation as one of considerable ventilation methods.
High-Frequency Ventilation ; Humans ; Lung ; Respiration, Artificial ; Respiratory Distress Syndrome ; Tidal Volume

Breathing pattern parameters refer to the characteristic pattern parameters of respiratory movements, including the breathing amplitude and cycle, chest and abdomen contribution, coordination, etc. It is of great importance to analyze the breathing pattern parameters quantificationally when exploring the pathophysiological variations of breathing and providing instructions on pulmonary rehabilitation training. Our study provided detailed method to quantify breathing pattern parameters including respiratory rate, inspiratory time, expiratory time, inspiratory time proportion, tidal volume, chest respiratory contribution ratio, thoracoabdominal phase difference and peak inspiratory flow. We also brought in "respiratory signal quality index" to deal with the quality evaluation and quantification analysis of long-term thoracic-abdominal respiratory movement signal recorded, and proposed the way of analyzing the variance of breathing pattern parameters. On this basis, we collected chest and abdomen respiratory movement signals in 23 chronic obstructive pulmonary disease (COPD) patients and 22 normal pulmonary function subjects under spontaneous state in a 15 minute-interval using portable cardio-pulmonary monitoring system. We then quantified subjects' breathing pattern parameters and variability. The results showed great difference between the COPD patients and the controls in terms of respiratory rate, inspiratory time, expiratory time, thoracoabdominal phase difference and peak inspiratory flow. COPD patients also showed greater variance of breathing pattern parameters than the controls, and unsynchronized thoracic-abdominal movements were even observed among several patients. Therefore, the quantification and analyzing method of breathing pattern parameters based on the portable cardiopulmonary parameters monitoring system might assist the diagnosis and assessment of respiratory system diseases and hopefully provide new parameters and indexes for monitoring the physical status of patients with cardiopulmonary disease.
Humans ; Lung ; Pulmonary Disease, Chronic Obstructive ; Respiration ; Tidal Volume ; Wearable Electronic Devices

OBJECTIVE: To study the characteristics of pulmonary function in children with pertussis-like coughing caused by different pathogen infections. METHODS: The data on etiology and tidal breathing pulmonary function were collected from 95 hospitalized infants and young children with pertussis-like coughing. The tidal breathing pulmonary function was compared between these children and 67 healthy children. According to the type of pathogen, the children with pertussis-like coughing were classified to 6 groups: pertussis (n=17), viral infection (n=23), tuberculosis infection (n=6), Mycoplasma infection (n=9), other bacterial infection (n=8), and unknown pathogen (n=32). RESULTS: Among the 95 children with pertussis-like coughing, 15 (16%) had mild obstructive ventilatory dysfunction, 30 (32%) had moderate obstructive ventilatory dysfunction, and 22 (23%) had severe obstructive ventilatory dysfunction. Compared with the normal control group, the children with pertussis-like coughing had significant reductions in inspiratory-to-expiratory time ratio, ratio of time to peak tidal expiratory flow to total expiratory time (tPF%tE), and ratio of volume to peak tidal expiratory flow to total expiratory volume (vPF%vE) (P<0.05). The tuberculosis infection and Mycoplasma infection groups had a significantly lower tidal volume than the normal control group (P<0.05). All pathogen infection groups except the tuberculosis infection group had significantly lower tPF%tE and vPF%vE than the normal control group (P<0.05). The pertussis group had significantly lower tPF%tE and vPF%vE than the other infection groups (P<0.05). CONCLUSIONS Most of children with pertussis-like coughing have abnormal pulmonary functions. The children with Bordetella pertussis infection have the most severe pulmonary function impairment. Tidal breathing pulmonary function test may provide a reference for pathogen analysis of children with pertussis-like coughing.
Child ; Child, Preschool ; Humans ; Infant ; Lung ; Respiration ; Respiratory Function Tests ; Tidal Volume ; Whooping Cough

OBJECTIVE: To investigate the role and mechanism of Ly6C^high monocyte in mice with ventilator-induced lung injury (VILI). METHODS: Forty-eight healthy male SPF C57BL/6 mice were divided into spontaneous breathing group (n = 8), normal tidal volume (VT) group (VT was 8 mL/kg, n = 8), and high VT group (VT was 20 mL/kg, n = 32). The mice in the high VT group were subdivided into 1, 2, 3 and 4 hours subgroups, with 8 mice in each subgroup. All mice underwent direct tracheal intubation, those in the spontaneous breathing group maintained spontaneous breathing, and those in the normal VT group and high VT group were mechanically ventilated with different VT. After ventilation for 4 hours, bronchoalveolar lavage fluid (BALF) was collected to determine total protein, and the levels of inflammatory factors including tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were determined by enzyme-linked immune sorbent assay (ELISA). The lung tissues were harvested to determine the wet/dry (W/D) ratio, and lung tissue injury was assessed in terms of lung histopathologic examination after hematoxylin-eosin (HE) staining under the light microscope. The protein expressions of monocyte chemotactic protein-1 (MCP-1) and CC-chemokine receptor 2 (CCR2) in lung tissues were determined by Western Blot. Flow cytometry was used to detect the proportion of Ly6C^high monocyte in lung tissue. RESULTS: The histopathology of lung tissue structures was normal in the spontaneous breathing group and the normal VT group. Inflammatory reaction began to appear at 2 hours of high VT ventilation, and inflammatory reaction was gradually aggravated with the time extension. Compared with the spontaneous breathing group, the total protein, TNF-α, and IL-1β levels in BALF, the lung W/D ratio and MCP-1 expression were increased from 2 hours of high VT ventilation [total protein in BALF (g/L): 1.05±0.13 vs. 0.58±0.11, TNF-α in BALF (ng/L): 116.86±16.14 vs. 38.27±8.00, IL-1β in BALF (ng/L): 178.98±10.41 vs. 117.56±23.40, lung W/D ratio: 5.76±0.27 vs. 4.98±0.39, MCP-1/GAPDH: 0.87±0.19 vs. 0.29±0.12, all P < 0.05], and CCR2 expression and the proportion of Ly6C^high monocyte was significantly increased from 3 hours of high VT ventilation [CCR2/GAPDH: 0.84±0.19 vs. 0.24±0.11, Ly6C^high monocyte proportion: (9.01±2.47)% vs. (1.06±0.35)%, both P < 0.05], and they all showed an increased tendency with the time extension. There was no significant difference in the parameters mentioned above among the spontaneous breathing group, normal VT group and high VT ventilation 1-hour group. CONCLUSIONS Ly6C^high monocytes are involved in VILI, which aggravate VILI by activating the MCP-1/CCR2 axis.
Animals ; Antigens, Ly/metabolism* ; Lung ; Male ; Mice ; Mice, Inbred C57BL ; Monocytes ; Rats ; Rats, Sprague-Dawley ; Tidal Volume ; Tumor Necrosis Factor-alpha ; Ventilator-Induced Lung Injury

Pregnancy has increased susceptibility to H1N1 influenza virus infection. Maternal influenza infection is associated with increased risk of morbidity and mortality. A case of influenza A (H1N1) during late pregnancy (pregnancy 1, birth 0, pregnancy 30⁺² weeks) was admitted to the Second Affiliated Hospital of Kunming Medical University on December 16th, 2018. The patient was set on mechanical ventilation with a FiO₂ of 1.0, a positive end-expiratory pressure (PEEP) of 15 cmH₂O (1 cmH₂O = 0.098 kPa), and a tidal volume of 4-6 mL/kg (ideal body weight). However the pulse oxygen saturation (SpO₂) could only be maintained at about 0.85. The disease was controlled by the treatments of anti-infection, mechanical ventilation, immune therapy, nutritional support, preventive anticoagulant treatment by heparin sodium, adequate negative fluid balance, and other organ support therapy. This article introduced the treatment process of the patient in detail, and provided experience for clinical treatment.
Female ; Humans ; Influenza A Virus, H1N1 Subtype ; Influenza, Human ; Positive-Pressure Respiration ; Pregnancy ; Pregnancy Complications ; Respiratory Distress Syndrome ; Tidal Volume

The ventilator-induced lung injury (VILI) was centered on the "static" characteristics of the mechanical ventilation in early phases (tidal volume, plateau pressure, positive end-expiratory pressure and driving pressure). But the "dynamic" characteristics of ventilation must not be ignored (respiratory rate and flow). Mechanical energy and mechanical power (the pace of performing energy load) regarding all factor have won wide spread attention. The energy generated by mechanical ventilation is mainly used to expand respiratory system and overcome resistance, a fraction of energy acts on lung tissues probably inducing "heat" and inflammation that is related to lung injury. The review described recent conceptual advances regarding the mechanical energy and power, and the relationship with VILI, hoping to help further understanding the risk factors for VILI.
Humans ; Lung ; Positive-Pressure Respiration ; Respiration, Artificial ; Respiratory Distress Syndrome ; Tidal Volume ; Ventilator-Induced Lung Injury

Traditionally, adequate tidal volume is considered to be a necessary condition to support respiratory patient breathing. But the high frequency ventilation (HFV) with a small tidal volume can still support the respiratory patient breathing well. In order to further explore the mechanisms of HFV, the pendelluft ventilation between left and right lungs was proposed in this paper. And a test platform by using two fresh sheep lungs was developed for investigating the pendelluft ventilation between the left and right lungs. Furthermore, considering the viscous resistance ( ), inertance ( ) and lung compliance ( ) in the lung, a second-order lung ventilation model was designed to inspect and evaluate the pendelluft ventilation between left lung and right lungs. On referring to both results of experiments in practice and simulation in MATLAB Simulink, between the left and right lungs, the phase difference in their airflow happens during HFV at some frequencies. And the pendelluft ventilation between the left and right lungs is resulted by the phase difference, even if the total airflow entering a whole lung is 0. Under HFV, the pendelluft ventilation between left and right lungs will benefit the lungs being more adequately ventilated, and will be improve the utilization rate of oxygen in the lungs.
Animals ; High-Frequency Ventilation ; Humans ; Lung ; physiology ; Pulmonary Gas Exchange ; Respiration, Artificial ; Sheep ; Tidal Volume

This study was to design a chronic obstructive pulmonary disease (COPD) screening equipment, based on the dual-differential pressure throttling technique. The technique combined a wide range, but low-resolution ratio sensor and a narrow range, but high-resolution ratio one. It can accurately detect the indexes of forced vital capacity (FVC), forced expiratory volume in one second (FEV), one second rate(FEV/FVC (%)), and achieve them in a low-cost way. The new designed machine will be compared with a British machine, named ML-3500. The correlations of FVC and FEV between new machine and ML-3500 were 0.998 and 0.999, respectively. The P values of paired test of these two indexes were over 0.05. Bland-Altman analysis of FVC, FEV and FEV/FVC (%) showed that more than 90% of the scatter points of the three parameters fell within the consistency interval. This machine can be used to accurately screen COPD and its low-cost would be advantage to promote in large population.
Forced Expiratory Volume ; Humans ; Pulmonary Disease, Chronic Obstructive ; diagnosis ; Reproducibility of Results ; Respiratory Function Tests ; economics ; instrumentation ; Tidal Volume ; Vital Capacity

Two dogs underwent a combined laparoscopic ovariectomy and total laparoscopic gastropexy. The intra-abdominal pressure and pulmonary compliance decreased, but the peak airway pressure increased at 20 min after the start of gastropexy with intracorporeal suturing. Right chest auscultation and percussion revealed reduced breath sounds and hyper-resonance. No abnormalities in the functioning of the instruments or diaphragmatic defects were detected. The tidal volume was reduced and a positive end-expiratory pressure of 5 cmH₂O was applied. The right chest of the two dogs was drained off: 950 mL (case 1) and 250 mL (case 2) of gas. After thoracentesis, the pulmonary compliance improved and surgery was completed successfully. The postoperative chest radiographs highlighted the residual right pneumothorax.
Animals ; Auscultation ; Compliance ; Dogs ; Female ; Gastropexy ; Laparoscopy ; Ovariectomy ; Percussion ; Pneumothorax ; Positive-Pressure Respiration ; Radiography, Thoracic ; Thoracentesis ; Thorax ; Tidal Volume