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

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

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

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

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

This paper compares and describes the tidal volume (Vt) used in mechanically ventilated dogs under a range of clinical conditions. Twenty-eight dogs requiring mechanical ventilation (MV) were classified into 3 groups: healthy dogs mechanically ventilated during surgery (group I, n = 10), dogs requiring MV due to extra-pulmonary reasons (group II, n = 7), and dogs that required MV due to pulmonary pathologies (group III, n = 11). The median Vt used in each group was 16 mL/kg (interquartile range [IQR], 15.14–21) for group I, 12.59 mL/kg (IQR, 9–14.25) for group II, and 12.59 mL/kg (IQR, 10.15–14.96) for group III. The Vt used was significantly lower in group III than in group I (p = 0.016). The thoraco-pulmonary compliance was significantly higher in group I than in groups II and III (p = 0.011 and p = 0.006, respectively). The median driving pressure was similar among the groups with a median of 9, 11, and 10 cmH2O in groups I, II, and III, respectively (p = 0.260). Critically-ill dogs requiring MV due to the primary pulmonary pathology received a significantly lower Vt than healthy dogs but with a range of values that were markedly higher than those recommended by human guidelines.
Animals ; Compliance ; Dogs ; Humans ; Pathology ; Respiration, Artificial ; Tidal Volume ; Ventilator-Induced Lung Injury

Lung-protective ventilation (such as low tidal volume and application of positive end-expiratory pressure) is beneficial for patients with acute lung injury or acute respiratory distress syndrome (ARDS) and has become the standard treatment in intensive care unit (ICU). However, some experts now question whether the protective ventilation strategy for ARDS patients in the ICU is equally beneficial for patients after surgery, especially for most patients without any pre-existing lung lesions. This review will discuss preoperative, intraoperative, and postoperative lung protection strategies to reduce the risk of complications associated with anesthesia.
Humans ; Positive-Pressure Respiration ; Respiration, Artificial ; Respiratory Distress Syndrome, Adult ; Tidal Volume ; Ventilator-Induced Lung Injury

OBJECTIVE: To investigate the relationship between different tidal volume (VT) mechanical ventilation (MV) and autophagy and mitochondrial damage in rats. METHODS: A total of 120 clean-grade male Sprague-Dawley (SD) rats were divided into five groups (n = 24) by random number table method, and then given 0 (spontaneous breathing), 10, 20, 30, 40 mL/kg VT for MV. The rats in each group were subdivided into four subgroups of 1, 2, 3, and 4 hours according to ventilation time, with 6 rats in each subgroup. The lung tissue and bronchoalveolar lavage fluid (BALF) were harvested, and alveolar macrophages (AMs) and type II alveolar epithelial cells (AEC II) were cultured in vitro. The mRNA and protein expressions of autophagy-associated protein microtubule-associated protein 1 light chain 3B-II (LC3B-II) and autophagy-related genes Beclin1 and p62 were determined by reverse transcription-polymerase chain reaction (RT-PCR) or Western Blot. Lung autophagosome formation was observed under transmission electron microscope. The levels of adenosine triphosphate (ATP), reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) in lung tissue were determined for assessing mitochondrial damage. RESULTS: There were no significant differences in the mRNA and protein expressions of LC3B-II, p62 and Beclin1 at 1 hour after ventilation among the groups. With the prolonged ventilation time, the mRNA and protein expressions of LC3B-II, p62 and Beclin1 in MV groups were increased gradually, peaked at 2-3 hours, and they were increased significantly in 30 mL/kg VT group as compared with those in spontaneous respiration group with statistical significances [ventilation for 2 hours: LC3B-II mRNA (2^-ΔΔCt) was 2.44±0.24 vs. 1.12±0.04, LC3B-II/LC3B-I was 1.42±0.16 vs. 0.57±0.03, p62 mRNA (2^-ΔΔCt) was 2.96±0.14 vs. 1.14±0.02, Beclin1 mRNA (2^-ΔΔCt) was 2.80±0.13 vs. 1.14±0.02; ventilation for 3 hours: p62/β-actin was 1.14±0.15 vs. 0.55±0.04, Beclin1/β-actin was 1.27±0.06 vs. 0.87±0.04, all P < 0.05]. Autophagosomes and autolysosomes were found in AEC II after ventilation for 2 hours at 30 mL/kg VT by transmission electron microscopy, but not in AEC I. Compared with spontaneous breathing group, ATP synthesis in AMs was significantly decreased at 2 hours of ventilation in 30 mL/kg VT group (A value: 0.82±0.05 vs. 1.00±0.00, P < 0.05), ROS accumulate in AMs and AEC II were significantly increased [ROS in AMs: (33.83±4.00)% vs. (6.90±0.62)%, ROS in AEC II: (80.68±0.90)% vs. (2.16±0.19)%, both P < 0.05]. With the increase in VT and the prolongation of ventilation time, ATP and ROS levels in AMs and AEC II were gradually decreased, the ATP (A value) in AMs at 4 hours of ventilation in 40 mL/kg VT group was 0.41±0.05, the ROS in AMs was (12.95±0.88)%, and the ROS in AEC II was (40.43±2.29)%. With the increase in VT and the prolongation of ventilation time, MMP levels were gradually increased, the MMP (green/red fluorescence intensity ratio) in AMs at 2 hours of ventilation in 30 mL/kg VT group was 1.11±0.17, the MMP in AEC II was 0.96±0.04, and the MMP (green/red fluorescence intensity ratio) at 4 hours of ventilation in 40 mL/kg VT group was 0.51±0.07 and 0.49±0.06, respectively. CONCLUSIONS The MV with high VT could induce autophagy activation and mitochondrial damage in lung tissue of rats, and the longer the ventilation time, the more obvious autophagy in the lung.
Animals ; Autophagy/physiology* ; Male ; Mitochondria/pathology* ; Rats ; Rats, Sprague-Dawley ; Respiration, Artificial/adverse effects* ; Tidal Volume ; Time Factors ; Ventilator-Induced Lung Injury

OBJECTIVE: To update evidence on the effects of breathing exercises (BEs) on ventilation, exercise capacity, dyspnea, and quality of life (QoL) in chronic obstructive pulmonary disease (COPD) patients. METHODS: Randomized controlled trials investigating the effects of BEs in COPD patients published through May 2018, were retrieved from five electronic databases (MEDLINE, CINAHL, Cochrane, Scopus, and ScienceDirect). Risk of bias and quality of evidence were assessed, using Cochrane Collaboration’s tool, and the Grading of Recommendation Assessment, Development, and Evaluation (GRADE) approach, respectively. RESULTS: Nineteen studies (n=745), were included. Quality of evidence, was low to moderate. When compared to the control groups, respiratory rate significantly (p≤0.001) improved in the pursed-lip breathing (PLB), ventilatory feedback (VF) plus exercise, diaphragmatic breathing exercise (DBE), and combined BEs. Additionally, PLB significantly improved tidal volume (p<0.001), inspiratory time (p=0.007), and total respiratory time (p<0.001). VF plus exercise significantly improved inspiratory capacity (p<0.001), and singing significantly improved the physical component of QoL, than did the control groups (p<0.001). All BEs did not significantly improve dyspnea, compared to the controls (p>0.05). CONCLUSION: PLB, VF plus exercise, DBE, combined BEs, and singing could be used to improve ventilation and QoL. Based on low to moderate quality of evidence, use of these BEs to improve ventilation and QoL in COPD patients is conditional (Registration No. CRD42018102995).
Bias (Epidemiology) ; Breathing Exercises ; Dyspnea ; Humans ; Inspiratory Capacity ; Pulmonary Disease, Chronic Obstructive ; Quality of Life ; Respiration ; Respiratory Rate ; Singing ; Tidal Volume ; Ventilation

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