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

Cardiac Surgical Procedures ; adverse effects ; Humans ; Positive-Pressure Respiration ; methods ; Respiratory Insufficiency ; therapy

OBJECTIVETo study clinical effectiveness and possible side effects of lower tidal volume combine with lung recruitment on acute respiratory distress syndrome (ARDS) for post operative esophageal carcinoma surgery patients.

METHODSTwenty six hypoxemie post operative esophageal carcinoma surgery patients from Cancer Hospital and Peking Union Medical College Hospital were included from 1st January 2007 to 30th September 2009. There were 20 male and 6 female with an average age of 65.5 years (51 - 76 years). Circulation was stable among them. They could not weaned from mechanical ventilation due to ARDS. Bedside monitoring included noninvasive continuous artery blood pressure (NBP), pulse oximetry saturation (SPO2). Patients were ventilated on volume control mode. Tidal volumes set to 6 ml/kg. Recruitment maneuvers were conducted by stepwise rising of positive end expiratory pressure (PEEP) level. PEEP, fraction of inspired oxygen (FiO2), static compliance of lung (CLS) and arterial blood gas analysis (ABG) before and at 30 min after each of twice applying recruitment maneuvers were measured.

RESULTSFifty-two recruitments were completed on these 26 cases. PaO2/FiO2 improved significantly in 26 cases. The level of FiO2 were significantly lowered, CLS were increased significantly 30 min after each of twice applying recruitment maneuvers in all 26 cases. No complication was encountered. All patients were discharged successfully.

CONCLUSIONHypoxemia of ARDS following esophageal carcinoma surgery can be improved by lower tidal volume combine with lung recruitment maneuver.

Aged ; Esophageal Neoplasms ; surgery ; Female ; Humans ; Male ; Middle Aged ; Positive-Pressure Respiration ; Postoperative Complications ; therapy ; Respiration, Artificial ; adverse effects ; methods ; Respiratory Distress Syndrome, Adult ; etiology ; therapy ; Thoracotomy ; adverse effects ; Tidal Volume ; Treatment Outcome

OBJECTIVETo study the effects of high frequency oscillatory ventilation (HFOV) combined with incremental positive end-expiratory pressure (IP) on respiratory and circulatory functions, and lung histopathology of dogs with smoke inhalation injury.

METHODSAfter being treated with conventional mechanical ventilation, 12 dogs were inflicted with severe smoke inhalation injury and divided into group HFOV and group HFOV+IP according to the random number table, with 6 dogs in each group. Then they received corresponding ventilation for 8 hours respectively. Blood gas analysis results (pH value, PaO2 and PaCO2 levels) and hemodynamic parameters [heart rate, mean arterial pressure (MAP), pulmonary arterial pressure (PAP), central venous pressure (CVP), cardiac output (CO)] were recorded before injury, immediately after injury, and at post ventilation hour (PVH) 2, 4, 6, and 8. The dogs of two groups were sacrificed at PVH 8. A healthy dog without any treatment and a dog with smoke inhalation injury but no subsequent treatment were sacrificed in addition. Lung tissues of all dogs were obtained for histopathological observation. Lung injury score examination was conducted in both groups. Data were processed with rank sum test, analysis of variance of repeated measurement, and LSD- t test.

RESULTS(1) The PaO2 levels in both groups were significantly decreased immediately after injury, compared with those before injury (with t values respectively 4.960, 5.310, P values all below 0.01). The PaO2 levels in both groups from PVH 2 to PVH 8 were significantly increased, compared with those observed immediately after injury (with t values from 4.930 to 6.050, P values all below 0.01). At PVH 2, 4, and 8, PaO2 levels in group HFOV+IP were significantly higher than those in group HFOV (with t values from 3.775 to 5.774, P values all below 0.01); no statistically significant differences were observed in pH value and PaCO2 level at each time point between two groups (with t values from 0.002 to 0.997, P values all above 0.05). (2) There were no statistically significant differences in MAP, PAP, and CVP within two groups at each time point (with F values from 1.316 to 4.959, P values all above 0.05). In group HFOV, heart rate from PVH 2 to PVH 8 was significantly lower than that observed immediately after injury (with t values from 3.780 to 8.970, P values all below 0.01). In group HFOV+IP, CO at PVH 4, 6, and 8 was significantly lower than that observed immediately after injury (with t values from 3.990 to 11.200, P values all below 0.01). There were no statistically significant differences in MAP, PAP, and CVP between two groups at the same time point (with t values from 0.089 to 2.123, P values all above 0.05). At PVH 4, 6, and 8, heart rate in group HFOV+IP was higher than that in group HFOV (with t values from 2.931 to 7.229, P < 0.05 or P < 0.01), while CO was lower (with t values from 4.297 to 11.206, P values all below 0.01). (3) Compared with those of the healthy dog, inflammatory cell infiltration and bleeding in the lung were observed in alveolar space in both group HFOV and group HFOV+IP, while the degree was less serious than that of the dog with smoke inhalation injury only. Compared with those of group HFOV, inflammatory cell infiltration in group HFOV+IP was less significant, the alveolar structure was relatively intact, and no thickening of alveolar walls was observed. The lung injury score in group HFOV [(3.27 ± 0.24) points] was higher than that of group HFOV+IP [(2.79 ± 0.31) points, t = 27, P < 0.05].

CONCLUSIONSHFOV combined with IP can improve gas exchange and alleviate pulmonary injury without any adverse effect on blood gas analysis or hemodynamic parameters. Therefore, it may be considered as an appropriate mode of ventilation for the treatment of smoke inhalation injury.

Animals ; Blood Gas Analysis ; Burns, Inhalation ; physiopathology ; therapy ; Disease Models, Animal ; Dogs ; Hemodynamics ; High-Frequency Ventilation ; Male ; Positive-Pressure Respiration ; Smoke ; adverse effects

OBJECTIVETo investigate the effect of pentoxifylline on one-lung ventilation injury in rabbits.

METHODSTwenty rabbit models of one-lung ventilation by intrabronchial intubation after tracheotomy were randomly allocated in control group (with one-lung ventilation) and experiment group (with one-lung ventilation and intravenous pentoxifylline administration). One-lung ventilation was maintained for 3 h in both groups using the volume-control mode (tidal volume of 8 ml/kg at the frequency of 30 per min). Arterial blood samples were taken after anesthesia and at 3 h of one-lung ventilation for arterial blood gas analysis to obtain the oxygenation index. At the end of the experiment, the pulmonary wet/dry ratio (W/D), tumor necrosis factor-alpha (TNF-alpha), NO, malondialdehyde (MDA) and superoxide dismutase (SOD) contents in bronchoalveolar lavage fluid (BALF) were measured and the histological appearance of the lung tissue was observed.

RESULTSThe oxygenation index was significantly higher (P<0.05), W/D ratio lower (P<0.05), and contents of TNF-alpha, NO and MAD in the BALF lower in the experimental group than in the control group (P<0.05). The activity of SOD increased significantly in the experimental group as compared with the control group (P<0.01), and the rabbits in the experimental group showed milder pathological changes.

CONCLUSIONIntravenous pentoxifylline may improve pulmonary ventilation function and alleviate pulmonary injury, thus offering protection against pulmonary injury after one-lung ventilation.

Acute Lung Injury ; etiology ; prevention & control ; Animals ; Continuous Positive Airway Pressure ; methods ; Female ; Intubation, Intratracheal ; Male ; Pentoxifylline ; pharmacology ; Pulmonary Ventilation ; Rabbits ; Respiration, Artificial ; adverse effects ; methods

OBJECTIVETo compare the effects of high frequency oscillatory ventilation (HFOV) combined with incremental positive end-expiratory pressure (IP) and those of pure HFOV on myocardial ischemia and hypoxia and apoptosis of cardiomyocytes in dogs with smoke inhalation injury.

METHODSTwelve healthy male dogs were divided into group HFOV and group HFOV+IP according to the random number table, with 6 dogs in each group. After being treated with conventional mechanical ventilation, dogs in both groups were inflicted with severe smoke inhalation injury, and then they received corresponding ventilation for 8 hours respectively. After treatment, the blood samples were collected from heart to determine the activity of creatine kinase-MB (CK-MB) and lactate dehydrogenase 1 (LDH1) in plasma. The dogs were sacrificed later. Myocardium was obtained for determination of content of TNF-α per gram myocardium by ELISA, apoptotic rate of cardiomyocytes by flow cytometer, degree of hypoxia with HE staining, and qualitative and quantitative expression of actin (denoted as integral absorbance value) with streptavidin-biotin-peroxidase staining. Data were processed with t test. The relationship between the content of TNF-α per gram myocardium and the apoptotic rate of cardiomyocytes was assessed by Spearman linear correlation analysis.

RESULTS(1) After treatment for 8 h, the values of activity of CK-MB and LDH1 in plasma of dogs in group HFOV+IP were respectively (734 ± 70) and (182 ± 15) U/L, which were both lower than those in group HFOV [(831 ± 79) and (203 ± 16) U/L, with t values respectively 2.25 and 2.35, P values below 0.05]. (2) Compared with that in group HFOV [(0.060 ± 0.018) µg], the content of TNF-α per gram myocardium of dogs in group HFOV+IP after treatment for 8 h was decreased significantly [(0.040 ± 0.011) µg, t=2.32, P<0.05]. (3) Compared with that in group HFOV [(33.4 ± 2.2)%], the apoptotic rate of cardiomyocytes of dogs in group HFOV+IP after treatment for 8 h was significantly decreased [(28.2 ± 3.4)%, t=3.15, P<0.05]. There was a positive correlation between the content of TNF-α per gram myocardium and the apoptotic rate of cardiomyocytes (r=0.677, P<0.05). (4) HE staining showed that myocardial fibers of dogs in both groups were arranged in wave shape in different degrees, indicating there was myocardial hypoxia in different degrees. Compared with that of group HFOV, the degree of hypoxia in group HFOV+IP was slighter. (5) The results of immunohistochemical staining showed that there was less loss of actin in myocardial fibers of dogs in group HFOV+IP than in group HFOV. The expression level of actin in myocardium of dogs in group HFOV+IP after treatment for 8 h (194.7 ± 3.1) was obviously higher than that in group HFOV (172.9 ± 2.6, t=13.20, P<0.01).

CONCLUSIONSCompared with pure HFOV, HFOV combined with IP can alleviate the inflammatory reaction in myocardium of dogs, reduce the apoptosis of cardiomyocytes, and ameliorate the myocardial damage due to ischemia and hypoxia.

Animals ; Apoptosis ; physiology ; Burns, Inhalation ; physiopathology ; therapy ; Dogs ; High-Frequency Ventilation ; Hypoxia ; Male ; Myocardial Ischemia ; physiopathology ; Myocytes, Cardiac ; Positive-Pressure Respiration ; Respiration, Artificial ; Smoke ; adverse effects ; Smoke Inhalation Injury ; therapy ; Treatment Outcome ; Tumor Necrosis Factor-alpha

OBJECTIVETo observe and compare the effects of two kinds of lung recruitment maneuvers, namely sustained inflation (SI) and incremental positive end-expiratory pressure (PEEP) (IP) on oxygenation, respiratory mechanics, and hemodynamics of dogs with severe smoke inhalation injury.

METHODSAfter being treated with conventional mechanical ventilation, 12 dogs were inflicted with severe smoke inhalation injury. They were divided into group SI and group IP according to the random number table, with 6 dogs in each group. Dogs in group SI were subjected to continuous positive airway pressure ventilation, with inspiratory pressure of 25 cmH2O (1 cmH2o = 0. 098 kPa), and it was sustained for 20 s. PEEP level in group IP was gradually increased by 5 cmH2O every 5 min up to 25 cmH2O, and then it was decreased by 5 cmH2O every 5 min until reaching 2-3 cmH2O. Then the previous ventilation mode was resumed in both groups for 8 hours. Blood gas analysis (pH value, PaO2, and PaCO2), oxygenation index (OI), respiratory mechanics parameters [peak inspiratory pressure (PIP), mean airway pressure, and dynamic lung compliance], and hemodynamic parameters [heart rate, mean arterial pressure (MAP), pulmonary arterial pressure (PAP), and cardiac output (CO)] were recorded or calculated before injury, immediately after injury, and at post ventilation hour (PVH) 2, 4, 6, 8. Data were processed with analysis of variance of repeated measurement and LSD-t test.

RESULTS(1) At PVH 6 and 8, pH values of dogs in group SI were significantly lower than those in group IP (with t values respectively 2. 431 and 2. 261, P values below 0.05); PaO2 levels in group SI [(87 ± 24), (78 ± 14) mmHg, 1 mmHg =0. 133 kPa] were lower than those in group IP [ (114 ± 18) , (111 ± 17) mmHg, with t values respectively 2. 249 and 3.671, P <0.05 or P <0.01]; OI values in group SI were significantly higher than those in group IP (with t values respectively 2.363 and 5.010, P <0.05 or P <0.01). No significant differences were observed in PaCO2 level within each group or between the two groups (with t values from 0. 119 to 1. 042, P values above 0.05). Compared with those observed immediately after injury, the pH values were significantly lowered (except for dogs in group IP at PVH 6 and 8, with t values from 2.292 to 3.222, P <0.05 or P <0.01), PaO2 levels were significantly elevated (with t values from 4. 443 to 6.315, P <0.05 or P <0.01), and OI values were significantly lowered (with t values from 2.773 to 9.789, P <0.05 orP <0.01) in both groups at all the treatment time points. (2) The PIP level at each time point showed no significant differences between two groups (with t values from 0. 399 to 1. 167, P values above 0. 05). At PVH 4 and 8, the mean airway .pressure values of dogs in group SI were significantly higher than those in group IP (with t values respectively 1.926 and 1. 190, P values below 0.05). At PVH 4, 6, and 8, the dynamic lung compliance levels of dogs in group SI [(9.5 ± 1.9), (12.8 ± 2. 1), (13. 1 ± 1.8) mL/cmH2O] were significantly lower than those in group IP [(11.6 ± 1.2), (15.4 ± 1.8), (14.9 ± 0.8) mL/cmH2O], with t values respectively 2. 289, 2. 303, 2. 238, P values below 0.05. Compared with those observed immediately after injury, PIP and the mean airway pressure values of dogs in two groups were significantly lowered at each treatment time point (with t values from 2. 271 to 7. 436, P <0. 05 or P < 0.01); the dynamic lung compliance levels were significantly elevated in both groups at PVH 6 and 8 (with t values from 2. 207 to 4. 195, P < 0.05 or P <0.01). (3) Heart rate, MAP, and PAP levels at each time point between two groups showed no significant differences (with t values from 0. 001 to 1. 170, P values above 0. 05). At PVH 4, 6, and 8, CO levels in group IP [(0. 6 + 0. 3), (0. 6 + 0. 4), (0. 5 + 0. 7) L/min] were significantly lower than those in group SI [(1.5 0.7), (1.8 + 1.1), (1.6 +0.9) L/min], with t values respectively 3. 028, 2.511, 2.363, P values below 0.05. Compared with that observed immediately after injury, CO level in group IP was significantly lowered at PVH 4, 6, or 8 (with t values respectively 2. 363, 2. 302, 2. 254, P values below 0. 05).

CONCLUSIONSBoth lung recruitment maneuvers can effectively improve oxygenation and lung compliance of dogs with severe smoke inhalation injury. IP is more effective in improving lung compliance, while SI shows less impact on the hemodynamic parameters.

Animals ; Blood Gas Analysis ; veterinary ; Dogs ; Hemodynamics ; Lung Compliance ; physiology ; Oxygen ; blood ; Oxygen Consumption ; physiology ; Positive-Pressure Respiration ; methods ; Respiration, Artificial ; Respiratory Mechanics ; Severity of Illness Index ; Smoke ; adverse effects ; Smoke Inhalation Injury ; physiopathology ; therapy

This study was conducted to evaluate the effectiveness and safety of a practical protocol for titrating positive end-expiratory pressure (PEEP) involving recruitment maneuver (RM) and decremental PEEP. Seventeen consecutive patients with acute lung injury who underwent PEEP titration were included in the analysis. After baseline ventilation, RM (continuous positive airway pressure, 35 cm H2O for 45 sec) was performed and PEEP was increased to 20 cmH2O or the highest PEEP guaranteeing the minimal tidal volume of 5 mL/kg. Then PEEP was decreased every 20 min in 2 cmH2O decrements. The "optimal" PEEP was defined as the lowest PEEP attainable without causing a significant drop (>10%) in PaO2. The "optimal PEEP" was 14.5 +/- 3.8 cmH2O. PaO2 /FI O2 ratio was 154.8 +/- 63.3 mmHg at baseline and improved to 290.0 +/- 96.4 mmHg at highest PEEP and 302.7 +/- 94.2 mmHg at "optimal PEEP", both significantly higher than baseline (p<0.05). Static compliance was significantly higher at "optimal" PEEP (27.2 +/- 10.4 mL/ cmH2O) compared to highest PEEP (22.3 +/- 7.7 mL/cmH2O) (p<0.05). Three patients experienced transient hypotension and one patient experienced atrial premature contractions. No patient had gross barotrauma. PEEP titration protocol involving RM and PEEP decrement was effective in improving oxygenation and was generally welltolerated.
Adult ; Aged ; Aged, 80 and over ; Blood Pressure ; Female ; Heart Rate ; Human ; Male ; Middle Aged ; Oxygen/blood ; Pneumonia/therapy ; Positive-Pressure Respiration/adverse effects/*methods ; Pulmonary Gas Exchange ; Respiratory Distress Syndrome, Adult/*therapy ; Retrospective Studies

Bronchoalveolar Lavage ; Bronchopulmonary Dysplasia ; etiology ; therapy ; Humans ; Infant, Newborn ; Infant, Premature ; Infant, Very Low Birth Weight ; Intubation, Intratracheal ; adverse effects ; Male ; Positive-Pressure Respiration ; Respiratory Insufficiency ; etiology ; therapy ; Treatment Outcome

BACKGROUNDAlthough severe encephalopathy has been proposed as a possible contraindication to the use of noninvasive positive-pressure ventilation (NPPV), increasing clinical reports showed it was effective in patients with impaired consciousness and even coma secondary to acute respiratory failure, especially hypercapnic acute respiratory failure (HARF). To further evaluate the effectiveness and safety of NPPV for severe hypercapnic encephalopathy, a prospective case-control study was conducted at a university respiratory intensive care unit (RICU) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) during the past 3 years.

METHODSForty-three of 68 consecutive AECOPD patients requiring ventilatory support for HARF were divided into 2 groups, which were carefully matched for age, sex, COPD course, tobacco use and previous hospitalization history, according to the severity of encephalopathy, 22 patients with Glasgow coma scale (GCS) < 10 served as group A and 21 with GCS = 10 as group B.

RESULTSCompared with group B, group A had a higher level of baseline arterial partial CO2 pressure ((102 +/- 27) mmHg vs (74 +/- 17) mmHg, P < 0.01), lower levels of GCS (7.5 +/- 1.9 vs 12.2 +/- 1.8, P < 0.01), arterial pH value (7.18 +/- 0.06 vs 7.28 +/- 0.07, P < 0.01) and partial O(2) pressure/fraction of inspired O(2) ratio (168 +/- 39 vs 189 +/- 33, P < 0.05). The NPPV success rate and hospital mortality were 73% (16/22) and 14% (3/22) respectively in group A, which were comparable to those in group B (68% (15/21) and 14% (3/21) respectively, all P > 0.05), but group A needed an average of 7 cm H2O higher of maximal pressure support during NPPV, and 4, 4 and 7 days longer of NPPV time, RICU stay and hospital stay respectively than group B (P < 0.05 or P < 0.01). NPPV therapy failed in 12 patients (6 in each group) because of excessive airway secretions (7 patients), hemodynamic instability (2), worsening of dyspnea and deterioration of gas exchange (2), and gastric content aspiration (1).

CONCLUSIONSSelected patients with severe hypercapnic encephalopathy secondary to HARF can be treated as effectively and safely with NPPV as awake patients with HARF due to AECOPD; a trial of NPPV should be instituted to reduce the need of endotracheal intubation in patients with severe hypercapnic encephalopathy who are otherwise good candidates for NPPV due to AECOPD.

Aged ; Brain Diseases ; therapy ; Carbon Dioxide ; blood ; Case-Control Studies ; Female ; Glasgow Coma Scale ; Humans ; Hypercapnia ; therapy ; Male ; Middle Aged ; Oxygen ; blood ; Positive-Pressure Respiration ; adverse effects ; Prospective Studies ; Pulmonary Disease, Chronic Obstructive ; complications