OBJECTIVETo investigate the pulmonary function after treatment in neonates with respiratory distress syndrome (RDS) at varying disease severity levels and different gestational ages.

METHODSA total of 107 neonates with RDS were divided into <34 weeks group (65 neonates), late preterm group (21 neonates), full-term group (21 neonates). Another 121 non-RDS children were enrolled as the control group. According to the severity of RDS, the RDS neonates were divided into mild RDS group (grades 1 and 2; 76 neonates), and severe RDS (grades 3 and 4; 21 neonates). The tidal breathing pulmonary function was measured at a corrected gestational age of 44weeks.

RESULTSThe pulmonary function parameters showed no significant differences across the groups of RDS neonates of different gestational ages; the tidal volume per kilogram of body weight (VT/kg) showed no significant difference between the RDS and non-RDS groups, while the RDS group had significantly higher ratio of time to peak tidal expiratory flow to total expiratory time (tPTEF/tE) and ratio of volume to peak tidal expiratory flow to total expiratory volume (vPTEF/vE) than the non-RDS group of the same gestational age (P<0.05). At a corrected gestational age of 44 weeks, the two groups of neonates with varying severity levels of RDS had significantly lower tPTEF/tE and vPTEF/vE than the control group (P<0.05), and tPTEF/tE and vPTEF/vE tended to decrease with the increasing severity level of RDS.

CONCLUSIONSNeonates with RDS have significantly decreased pulmonary function than those without RDS. At a corrected gestational age of 44 weeks, the tidal breathing pulmonary function in neonates with RDS is not associated with gestational age, but is associated with the severity of RDS.

Female ; Gestational Age ; Humans ; Infant, Newborn ; Lung ; physiopathology ; Male ; Respiratory Distress Syndrome, Newborn ; physiopathology

The effect of high frequency oscillatory ventilation (HFOV) at early stage on hemodynamic parameters, extravascular lung water (EVLW), lung capillary permeability, CC16 and sICAM-1 in piglets with pulmonary or extrapulmonary acute respiratory distress syndrome (ARDS) was explored. Central vein pressure (CVP) and pulse indicator continuous cardiac output (PiCCO) were monitored in 12 anesthetized and intubated healthy piglets. Pulmonary ARDS (ARDSp) and extrapulmonary ARDS (ARDSexp) models were respectively established by lung lavage of saline solution and intravenous injection of oleic acid. Then the piglets received HFOV for 4 h. EVLW index (EVLWI), EVLW/intratroracic blood volume (ITBV) and pulmonary vascular permeability index (PVPI) were measured before and after modeling (T0 and T1), and T2 (1 h), T3 (2 h), T4 (3 h) and T5 (4 h) after HFOV. CC16 and sICAM-1 were also detected at T1 and T5. Results showed at T1, T3, T4 and T5, EVLWI was increased more significantly in ARDSp group than in ARDSexp group (P<0.05). The EVLWI in ARDSp group was increased at T1 (P=0.008), and sustained continuously within 2 h (P=0.679, P=0.216), but decreased at T4 (P=0.007) and T5 (P=0.037). The EVLWI in ARDSexp group was also increased at T1 (P=0.003), but significantly decreased at T3 (P=0.002) and T4 (P=0.019). PVPI was increased after modeling in both two groups (P=0.004, P=0.012), but there was no significant change within 4 h (T5) under HFOV in ARDSp group, while PVPI showed the increasing trends at first, then decreased in ARDSexp group after HFOV. The changes of EVLW/ITBV were similar to those of PVPI. No significant differences were found in ΔEVLWI (P=0.13), ΔPVPI (P=0.28) and ΔEVLW/ITBV between the two groups (P=0.63). The significant decreases in both CC16 and sICAM-1 were found in both two groups 4 h after HFOV, but there was no significant difference between the two groups. It was concluded that EVLWI and lung capillary permeability were markedly increased in ARDSp and ARDSexp groups. EVLW could be decreased 4 h after the HFOV treatment. HFOV, EVLW/ITBV and PVPI were increased slightly at first, and then decreased in ARDSexp group, while in ARDSp group no significant difference was found after modeling. No significant differences were found in the decreases in EVLW and lung capillary permeability 4 h after HFOV.
Animals ; Capillaries ; physiopathology ; High-Frequency Ventilation ; Lung ; blood supply ; Respiratory Distress Syndrome, Adult ; physiopathology ; Swine

Among the fire victims, respiratory tract injury resulted from smoke inhalation is the major cause of death. Particulate substances in smoke, toxic and harmful gas, and chemical substances act together would rapidly induce the occurrence of dramatic pathophysiologic reaction in the respiratory tract, resulting in acute injury to the respiratory tract, thus inducing serious injury to it and acute respiratory distress syndrome, leading to death of the victims. In recent years, the pathophysiologic mechanism of severe smoke inhalation injury has been gradually clarified, thus appreciable advances in its treatment have been achieved. This paper is a brief review of above-mentioned aspects.
Burns, Inhalation ; pathology ; physiopathology ; Fires ; Humans ; Respiratory Distress Syndrome, Adult ; physiopathology ; Smoke ; adverse effects ; Smoke Inhalation Injury ; pathology ; physiopathology

Pathologic findings of scrub typhus have been characterized by vasculitis of the microvasculature of the involved organ resulting from a direct invasion by Orientia tsutsugamushi. We experienced a case of acute respiratory distress syndrome (ARDS) associated with scrub typhus. The case was proven by eschar and high titer of serum IgM antibody (positive at 1:1280). Open lung biopsy showed diffuse alveolar damage (DAD) in the organizing stage without evidence of vasculitis. Immunofluorescent antibody staining and polymerase chain reaction for O. tsutsugamushi failed to demonstrate the organism in the lung tissue. The patient expired due to progressive respiratory failure despite doxycycline therapy. Immunologic mechanism, without direct invasion of the organism, may participate in the pathogenesis of ARDS associated with scrub typhus.
Acute Disease ; Aged ; Case Report ; Fatal Outcome ; Female ; Human ; Infant, Newborn ; Pulmonary Alveoli/pathology ; Pulmonary Alveoli/injuries ; Respiratory Distress Syndrome/physiopathology ; Respiratory Distress Syndrome/pathology ; Respiratory Distress Syndrome/immunology ; Respiratory Distress Syndrome/complications* ; Scrub Typhus/physiopathology ; Scrub Typhus/pathology ; Scrub Typhus/immunology ; Scrub Typhus/complications* ; Vasculitis

OBJECTIVETo evaluate the acute physiology and chronic health evaluation III (APACHE III) and acute lung injury (ALI) scale in the severity and prognosis of severe acute respiratory syndrome (SARS).

METHODSThe clinical data of 38 SARS patients, including survivors (24 cases) and no survivors (14 cases) were collected and evaluated with APACHE III and ALI scoring systems. The correlation of scores and prognosis was evaluated.

RESULTSThe scores of APACHE III in the non survivors were higher remarkably than those in the survivor group (P < 0.001). The scores of APACHE III had positive correlation with the overall fatality rate. When the scores of APACHE III was higher than 60, the mortality increased obviously (chi(2) = 3.886, P < 0.05). Elderly patients with SARS who were over 60 years old had a high mortality (chi(2) = 8.660, P < 0.05). The scores of ALI in the non survivors had not statistical significance than those in the survivor group (P = 0.127).

CONCLUSIONSThe score of APACHE III in the SARS are correlated with the patient's condition and prognosis. Elderly patients with SARS have a high mortality.

APACHE ; Adult ; Aged ; Aged, 80 and over ; Female ; Humans ; Male ; Middle Aged ; Prognosis ; Respiratory Distress Syndrome, Adult ; etiology ; physiopathology ; Severe Acute Respiratory Syndrome ; physiopathology

This study was performed to elucidate the mechanism of improved oxygenation after surfactant replacement therapy in respiratory distress syndrome (RDS) of the newborn infants. In 26 newborns with RDS, end tidal-CO2 tension (PetCO2), arterial blood gas analysis and pulmonary function tests were measured at baseline, 30 min, 2 hr and 6 hr after surfactant administration. The changes in dead space/tidal volume ratio (VD/VT ratio=(PaCO2-PetCO2)/PaCO2), oxygenation index and arterial-alveolar partial pressure difference for oxygen ((A-a)DO2) were elucidated and correlated with pulmonary mechanics. Oxygenation index and (A-a)DO2 improved, and VD/VT ratio decreased progressively after surfactant administration, becoming significantly different from the baseline at 30 min and thereafter with administration of surfactant. Pulmonary mechanics did not change significantly during the observation period. VD/VT ratio showed close correlation with OI and (A-a)DO2, but not with pulmonary mechanics. These results suggest that decreased physiologic dead space resulting from the recruitment of atelectatic alveoli rather than improvement in pulmonary mechanics is primarily responsible for the improved oxygenation after surfactant therapy in the RDS of newborn.
Airway Resistance ; Human ; Infant, Newborn ; Lung/physiopathology* ; Lung Compliance ; Pulmonary Gas Exchange ; Pulmonary Surfactants/therapeutic use* ; Respiratory Dead Space* ; Respiratory Distress Syndrome/physiopathology ; Respiratory Distress Syndrome/drug therapy* ; Tidal Volume*

OBJECTIVETo compare the therapeutic effects of high-frequency oscillatory ventilation+pulmonary surfactant (HFOV+PS), conventional mechanical ventilation+pulmonary surfactant (CMV+PS), and conventional mechanical ventilation (CMV) alone for acute lung injury/acute respiratory distress syndrome (ALI/ARDS) in neonates.

METHODSA total of 136 neonates with ALI/ARDS were enrolled, among whom 73 had ALI and 63 had ARDS. They were divided into HFOV+PS group (n=45), CMV+PS group (n=53), and CMV group (n=38). The neonates in the first two groups were given PS at a dose of 70-100 mg/kg. The partial pressure of oxygen (PaO), partial pressure of carbon dioxide (PaCO), PaO/fraction of inspired oxygen (FiO), oxygenation index (OI), and respiratory index (RI) were measured at 0, 12, 24, 48, and 72 hours of mechanical ventilation.

RESULTSAt 12, 24, and 48 hours of mechanical ventilation, the HFOV+PS group had higher PaOand lower PaCOthan the CMV+PS and CMV groups (P<0.05). At 12, 24, 48, and 72 hours of mechanical ventilation, the HFOV+PS group had higher PaO/FiOand lower OI and RI than the CMV+PS and CMV groups (P<0.05). The HFOV+PS group had shorter durations of mechanical ventilation and oxygen use than the CMV+PS and CMV groups (P<0.05). There were no significant differences in the incidence rates of air leakage and intracranial hemorrhage and cure rate between the three groups.

CONCLUSIONSIn neonates with ALI/ARDS, HFOV combined with PS can improve pulmonary function more effectively and shorten the durations of mechanical ventilation and oxygen use compared with CMV+PS and CMV alone. It does not increase the incidence of complications.

Acute Lung Injury ; physiopathology ; therapy ; Combined Modality Therapy ; Female ; High-Frequency Ventilation ; Humans ; Infant, Newborn ; Male ; Pulmonary Surfactants ; therapeutic use ; Respiratory Distress Syndrome, Newborn ; physiopathology ; therapy ; Respiratory Mechanics

OBJECTIVEThe authors compared the protective ventilation strategies with the assistance of pulmonary mechanic measurements (PM) to the conventional ventilation practice in order to investigate the incidence of VALI, explore the best ventilator settings in RDS and the clinical effects of hypercapnia in neonates.

METHODSOne hundred and ten newborn infants, diagnosed as respiratory distress syndrome of neonatal and needed ventilator support, were recruited from the intensive care unit from 1994 to 2001. Infants with RDS were divided into non-pulmonary mechanics measurement (NPM) group and pulmonary mechanics measurement (PM) group. The ventilator settings, artery blood gas analysis, ventilator-associated lung injury and other clinical data were analyzed and compared.

RESULTSIn the PM group, expiratory tidal volume of (7.70 +/- 1.05) ml/kg, C(20)/C of (1.98 +/- 0.92) and time constant of (0.09 +/- 0.03) sec were measured. Ventilator setting in PM group [PIP of (26.7 +/- 1.7) cmH(2)O, MAP of (11.9 +/- 2.0) cmH(2)O, Ti of (0.45 +/- 0.10) sec] were significantly less than those in NPM group [PIP of (30.5 +/- 3.4) cmH(2)O, MAP of (14.9 +/- 3.4) cmH(2)O, Ti of (0.75 +/- 0.10) sec P < 0.001, respectively]. No differences were noted in demographic data between the two groups regarding to the pH (7.30 +/- 0.04 vs 7.31 +/- 0.10), PaO(2) [(59 +/- 16) vs (57 +/- 17) mmHg], heart rate [(145 +/- 6) vs (144 +/- 8) bpm] and blood pressure [(39.0 +/- 3.6) vs (40.0 +/- 4.6) mmHg], except for PaCO(2) in PM group which was significantly higher than that in NPM group [(48 +/- 6) vs (40 +/- 10) mmHg, P < 0.001]. OI in PM group was significantly less than that in NPM group (14 +/- 8 vs 19 +/- 13, P < 0.05). Incidence of ventilator-associated lung injury in PM group was significantly lower than that in NPM group (13% vs 32%, P < 0.05). No differences were noted in demographic data between the two groups regarding to the length of ventilator support [(4.2 +/- 1.7) vs (3.9 +/- 1.8) day], length of supplemental oxygen requirements [(13 +/- 7) vs (11 +/- 7) day], length of hospitalization [(22 +/- 11) vs (19 +/- 14) day], mortality (8% vs 14%), incidence of PDA (33 vs 36%) and IVH (40% vs 42%).

CONCLUSIONSThe assistance use of pulmonary mechanics measurement can guide the ventilator adjustment and decrease the ventilator-associated lung injury in neonatal RDS. The low PIP, low tidal volume, shorter inspiratory time and adequate PEEP strategies in the treatment of RDS showed no significant effects on the oxygenation in neonates. The mild permissive hypercarbia in newborn did not increase the incidence of IVH.

Blood Gas Analysis ; Female ; Humans ; Infant, Newborn ; Intensive Care Units, Neonatal ; Male ; Respiration, Artificial ; methods ; Respiratory Distress Syndrome, Newborn ; physiopathology ; therapy ; Respiratory System ; physiopathology

OBJECTIVETo assess the incidence, etiology, physiological and clinical features, mortality, and predictors of acute respiratory distress syndrome (ARDS) in intensive care unit (ICU).

METHODSA retrospective analysis of 5 314 patients admitted to the ICU of our hospital from April 1994 to December 2003 was performed in this study. The ARDS patients were identified with the criteria of the American-European Consensus Conference (AECC). Acute physiology and chronic health evaluation III (APACHE III), multiple organ dysfunction syndrome score (MODS score), and lung injury score (LIS) were determined on the onset day of ARDS for all the patients. Other recorded variables included age, sex, biochemical indicators, blood gas analysis, length of stay in ICU, length of ventilation, presence or absence of tracheostomy, ventilation variables, elective operation or emergency operation.

RESULTSTotally, 131 patients (2.5%) developed ARDS, among whom, 12 patients were excluded from this study because they died within 24 hours and other 4 patients were also excluded for their incomplete information. Therefore, there were only 115 cases (62 males and 53 females, aged 22-75 years, 58 years on average) left, accounting for 2.2% of the total admitted patients. Their average ICU stay was (11.27+/-7.24) days and APACHE III score was 17.23+/-7.21. Pneumonia and sepsis were the main cause of ARDS. The non-survivors were obviously older and showed significant difference in the ICU length of stay and length of ventilation as compared with the survivors. On admission, the non-survivors had significantly higher MODS and lower BE (base excess). The hospital mortality was 55.7%. The main cause of death was multiple organ failure. Predictors of death at the onset of ARDS were advanced age, MODS > or = to 8, and LIS > or = 2.76.

CONCLUSIONSARDS is a frequent syndrome in this cohort. Sepsis and pneumonia are the most common risk factors. The main cause of death is multiple organ failure. The mortality is high but similar to most recent series including severe comorbidities. Based on this patient population, advanced age, MODS score, and LIS may be the important prognostic indicators for ARDS.

Adult ; Aged ; Female ; Humans ; Intensive Care Units ; Male ; Middle Aged ; Prognosis ; Respiratory Distress Syndrome, Adult ; mortality ; physiopathology ; Retrospective Studies

PURPOSEThis prospective observational study aims to evaluate the accuracy of dead-space fraction derived from the ventilator volumetric capnography (volumetric CO₂) or a prediction equation to predict the survival of mechanically ventilated patients with acute respiratory distress syndrome (ARDS).

METHODSConsecutive VD/VT measurements were obtained based upon a prediction equation validated by Frankenfield et al for dead-space ventilation fraction: VD/VT = 0.320 + 0.0106 (PaCO₂-ETCO₂)⁺ 0.003 (RR)⁺0.0015 (age) in adult patients who had infection-related severe pneumonia and were confirmed as having ARDS. Here PaCO₂ is the arterial partial pressure of carbon dioxide in mmHg; ETCO₂, the end- tidal carbon dioxide measurement in mmHg; RR, respiratory rate per minute; and age in years. Once the patient had intubation, positive end expiratory pressure was adjusted and after Phigh reached a steady state, VD/VT was measured and recorded as the data for the first day. VD/VT measurement was repeated on days 2, 3, 4, 5 and 6. Meanwhile we collected dead-space fraction directly from the ventilator volu- metric CO₂ and recorded it as Vd/Vt. We analyzed the changes in VD/VT and Vd/Vt over the 6-day period to determine their accuracy in predicting the survival of ARDS patients.

RESULTSOverall, 46 patients with ARDS met the inclusion criteria and 24 of them died. During the first 6 days of intubation, VD/VT was significantly higher in nonsurvivors on day 4 (0.70 ± 0.01 vs 0.57 ± 0.01), day 5 (0.73 ± 0.01 vs. 0.54 ± 0.01), and day 6 (0.73 ± 0.02 vs. 0.54 ± 0.01) (all p =0.000). Vd/Vt showed no significant difference on days 1e4 but it was much higher in nonsurvivors on day 5 (0.45 ± 0.04 vs. 0.41 ± 0.06) and day 6 (0.47 ± 0.05 vs. 0.40 ± 0.03) (both p=0.008). VD/VT on the fourth day was more accurate to predict survival than Vd/Vt. The area under the receiver-operating characteristic curve for VD/VT and Vd/Vt in evaluating ARDS patients survival was day 4 (0.974 ± 0.093 vs. 0.701 ± 0.023, p = 0.0024) with the 95% confidence interval being 0.857-0.999 vs. 0.525-0.841.

CONCLUSIONCompared with Vd/Vt derived from ventilator volumetric CO₂, VD/VT on day 4 calculated by Frankenfield et al's equation can more accurately predict the survival of ARDS patients.

Adult ; Capnography ; Female ; Humans ; Male ; Middle Aged ; Prospective Studies ; ROC Curve ; Respiration, Artificial ; Respiratory Dead Space ; physiology ; Respiratory Distress Syndrome, Adult ; mortality ; physiopathology