摘要:

ObjectivesTo determine the cardiorespiratory effects of manual expiratory rib cage compression in mechanically ventilated patients recovering from acute severe asthma; and to extrapolate these findings to emergency asthma management where ventilation cannot be achieved by positive-pressure ventilation.DesignA prospective, clinical study.SettingIntensive care unit.PatientsFour intubated, mechanically ventilated (volume-controlled), adult patients recovering from acute severe asthma.InterventionsPatients were studied before, during, and after a 2- to 3-min period of manual compressions applied bilaterally over the lower rib cage (ribs 8 to 10) during consecutive tidal expirations.Measurements and Main ResultsAir flow (pneumotachograph), airway pressure, radial or brachial arterial pressure, and the hand pressure applied to the patient's rib cage were monitored and recorded on magnetic tape. Playback of the recorded data enabled measurement of changes in lung volume (air flow integration). Changes during rib cage compression consisted chiefly of small decreases in lung volume and peak inspiratory airway pressure that were only observed in the least obstructed patient and were fully reversed after the cessation of compressions. Air flow-time and air flow-volume plots demonstrated expiratory air flow limitation during essentially the entire tidal expiration in each patient, except the least obstructed patient.ConclusionThe results suggest that manual compression of the rib cage during consecutive tidal expirations would be ineffective in reducing pulmonary hyperinflation during the emergency management of asthma when air flow obstruction is so severe that ventilation cannot be achieved by positive-pressure ventilation. (Crit Care Med 1998; 26:1361-1367)

ISSN:0090-3493    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

ObjectivesTo assess the efficacy of the Simplified Acute Physiology Score (SAPS II) in intermediate care units. A number of patients hospitalized in the intensive care unit (ICU) could be hospitalized in alternative structures, intermediate care units, which are equipped to handle their monitoring needs and able to provide adequate treatment at a lower cost. Characterization of the patients relies on the assessment of their severity of illness by severity scores. The efficiency of severity scores has been established in ICU patients, but not in the setting of intermediate care units.DesignProspective study.SettingIntermediate care unit of a multidisciplinary hospital.PatientsFour hundred thirty-three patients admitted to the intermediate care unit.InterventionsNone.Measurements and Main Results0.5). The discriminant power of SAPS II, measured by the area under the receiver operating characteristic curve was excellent (0.85 +/- 0.04).ConclusionsThe SAPS II assessment of severity of illness in patients admitted to an intermediate care unit is reliable. These results will need to be confirmed, using different patient samplings from intermediate care units. (Crit Care Med 1998; 26:1368-1371)

ISSN:0090-3493    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

ObjectiveTo determine the contribution of soft-tissue trauma plus hemorrhage, bone fracture and hemorrhage, as well as the contribution of bone fracture, soft-tissue trauma and hemorrhage on host immune function.SubjectsAdult male mice (n = 6/group).DesignProspective, randomized, controlled study.SettingAnimal laboratory at a university-affiliated hospital.InterventionsClosed-bone fracture (right lower leg; external fixation) and/or soft-tissue trauma (2.5-cm midline laparotomy, closed in two layers) were induced before hemorrhagic shock (mean arterial blood pressure of 35 +/- 5 (SEM) mm Hg for 90 mins, followed by fluid resuscitation) in male C3H/HeN mice and the animals were killed at 72 hrs after initiation of the experiment.Measurements and Main ResultsSplenocyte interleukin (IL)-2 and IL-3 release capacity, as well as splenic and peritoneal macrophage IL-1 and IL-6 release capacity were determined. Different traumatic insults, i.e., bone fracture or soft-tissue trauma in conjunction with hemorrhage, produced comparable immune depression. More significant depression of splenocyte IL-2 and IL-3 release capacity as well as macrophage IL-1 and IL-6 release capacity occurred with the combined insult (i.e., bone fracture/soft-tissue injury and hemorrhage) than after bone injury or tissue trauma alone with hemorrhage.ConclusionsThe combination of closed-bone fracture and soft-tissue trauma before hemorrhage leads to even more compromised immunity than either soft-tissue trauma or closed-bone fracture along with hemorrhage. The markedly depressed immune function following bone injury, soft-tissue trauma, and hemorrhagic shock may contribute to the increased susceptibility of severely injured patients to sepsis and the ensuing multiple organ failure in the clinical situation. (Crit Care Med 1998; 26:1372-1378)

ISSN:0090-3493    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

ObjectiveTo evaluate the efficacy of treating endotoxin-induced lung injury with single dose exogenous surfactant and positive end-expiratory pressure (PEEP).DesignProspective trial.SettingLaboratory at a university medical center.SubjectsNineteen certified healthy pigs, weighing 15 to 20 kg.InterventionsPigs were anesthetized and surgically prepared for hemodynamic and lung function measurements. Animals were randomized into four groups: a) Control pigs (n = 4) received an intravenous infusion of saline without Escherichia coli lipopolysaccharide (LPS); b) the LPS group (n = 5) received an intravenous infusion of saline containing LPS (100 [micro sign]g/kg); c) the PEEP plus saline group (n = 5) received an intravenous infusion of saline containing LPS. Two hours after LPS infusion, saline was instilled into the lung as a control for surfactant instillation, and the animals were placed on 7.5 cm H2O of PEEP; d) the PEEP plus surfactant group (n = 5) received an intravenous infusion of saline containing LPS. Two hours following LPS infusion, surfactant (50 mg/kg) was instilled into the lung and the animals were placed on 7.5 cm H2O of PEEP. PEEP was applied first and surfactant or saline was instilled into the lung while maintaining positive pressure ventilation. All groups were studied for 6 hrs after the start of LPS injection. At necropsy, bronchoalveolar lavage was performed and the right middle lung lobe was fixed for histologic analysis.Measurements and Main ResultsCompared with LPS without treatment, PEEP plus surfactant significantly increased PaO2(PEEP plus surfactant = 156.6 +/- 18.6 [SEM] torr [20.8 +/- 2.5 kPa]; LPS = 79.2 +/- 21.9 torr [10.5 +/- 2.9 kPa]; p < .05), and decreased venous admixture (PEEP plus surfactant = 12.5 +/- 2.0%; LPS = 46.9 +/- 14.2%; p < .05) 5 hrs after LPS infusion. These changes were not significant 6 hrs after LPS infusion. PEEP plus surfactant did not alter ventilatory efficiency index (VEI = 3800/[peak airway pressure - PEEP] [center dot] respiratory rate [center dot] PaCO2), or static compliance as compared with LPS without treatment at any time point. Cytologic analysis of bronchoalveolar lavage fluid showed that surfactant treatment significantly increased the percentage of alveolar neutrophils as compared with LPS without treatment (PEEP plus surfactant = 39.1 +/- 5.5%; LPS = 17.4 +/- 6.6%; p < .05). Histologic analysis showed that LPS caused edema accumulation around the airways and pulmonary vessels, and a significant increase in the number of sequestered leukocytes (LPS group = 3.4 +/- 0.2 cells/6400 [micro sign]2; control group = 1.3 +/- 0.1 cells/6400 [micro sign]2; p < .05). PEEP plus saline and PEEP plus surfactant significantly increased the total number of sequestered leukocytes in the pulmonary parenchyma (PEEP plus surfactant = 8.2 +/- 0.7 cells/6400 [micro sign]2; PEEP plus saline = 3.9 +/- 0.2 cells/6400 [micro sign]2; p < .05) compared with the control and LPS groups.ConclusionsWe conclude that PEEP plus surfactant treatment of endotoxin-induced lung injury transiently improves oxygenation, but is unable to maintain this salutary effect indefinitely. Thus, repeat bolus dosing of surfactant or bolus treatment followed by continuous aerosol delivery may be necessary for a continuous beneficial effect. (Crit Care Med 1998; 26:1379-1389)

ISSN:0090-3493    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

ObjectivesInhaled nitric oxide (NO) reduces pulmonary hypertension in acute respiratory failure. Soluble nitric oxide donors (NO/nucleophile adducts-NONOates) are less cumbersome to deliver and may offer clinical advantage compared with inhaled NO. The objective of this study was to examine the pulmonary and systemic hemodynamic effects of tracheal aerosolization of a new class of NONOates in a porcine model of experimentally induced pulmonary hypertension.DesignProspective, randomized, controlled study.SettingResearch laboratory.SubjectsYorkshire pigs (n = 18), weighing 11.4 to 16.4 kg.InterventionsIn anesthetized, mechanically ventilated, instrumented pigs, steady-state pulmonary hypertension (SSPH) was induced using a thromboxane agonist (U46619). Control animals received tracheal aerosolization of saline (n = 6); EP/NO animals received tracheal aerosolization of ethylputreanine NONOate (EP/NO, n = 6); and DMAEP/NO animals received aerosolized 2-(dimethylamino) ethylputreanine NONOate (DMAEP/NO, n = 6).Measurements and Main ResultsMean pulmonary (MPAP) and mean systemic arterial pressures (MAP), atrial pressures, cardiac output, and arterial blood gases were measured following drug instillation. DMAEP/NO animals had significant reductions in pulmonary vascular resistance index (PVRI) and MPAP at all time points compared with SSPH and control animals (p < .05), while systemic vascular resistance index did not change. EP/NO animals had a significant reduction in PVRI and MPAP at some time points compared with SSPH and control animals. For both NONOate-treated animal groups, MAP and cardiac index did not change significantly compared with SSPH and control animals (p < .05).ConclusionsIn this porcine model of pulmonary hypertension, intratracheal aerosolization of soluble NO donors results in sustained reduction of pulmonary hypertension without reducing systemic arterial pressure. Intermittent aerosolization of NONOates may be an alternative to continuously inhaled NO in the treatment of acute pulmonary hypertension. (Crit Care Med 1998; 26:1390-1396)

ISSN:0090-3493    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

ObjectivesDuring cardiopulmonary resuscitation (CPR), elimination of CO (2) was shown to be limited by low tissue perfusion, especially when very low perfusion pressures were generated. It has therefore been suggested that sodium bicarbonate (NaHCO3), by producing CO2, might aggravate the hypercarbic component of the existing acidosis and thereby worsen CPR outcome. The objectives of this study were to evaluate the effects of CO2producing and non-CO2producing buffers in a canine model of prolonged ventricular fibrillation followed by effective CPR.DesignProspective, randomized, controlled, blinded trial.SettingExperimental animal research laboratory in a university research center.SubjectsThirty-eight adult dogs, weighing 20 to 35 kg.InterventionsAnimals were prepared for study with thiopental followed by halothane, diazepam, and pancuronium. Ventricular fibrillation was electrically induced, and after 10 mins, CPR was initiated, including ventilation with an FIO2of 1.0, manual chest compressions, administration of epinephrine (0.1 mg/kg every 5 mins), and defibrillation. A dose of buffer, equivalent to 1 mmol/kg of NaHCO3, was administered every 10 mins from start of CPR. Animals were randomized to receive either NaHCO3, Carbicarb, THAM, or 0.9% sodium chloride (NaCl). CPR was continued for up to 40 mins or until return of spontaneous circulation.Measurements and Main ResultsBuffer-treated animals had a higher resuscitability rate compared with NaCl controls. Spontaneous circulation returned earlier and at a significantly higher rate after NaHCO3(in seven of nine dogs), and after Carbicarb (six of ten dogs) compared with NaCl controls (two of ten dogs). Spontaneous circulation was achieved twice as fast after NaHCO3compared with NaCl (14.6 vs. 28 mins, respectively). Hydrogen ion (H+) concentration and base excess, obtained 2 mins after the first buffer dose, were the best predictors of resuscitability. Arterial and mixed venous PCO2did not increase after NaHCO3or Carbicarb compared with NaCl.ConclusionsBuffer therapy promotes successful resuscitation after prolonged cardiac arrest, regardless of coronary perfusion pressure. NaHCO3, and to a lesser degree, Carbicarb, are beneficial in promoting early return of spontaneous circulation. When epinephrine is used to promote tissue perfusion, there is no evidence for hypercarbic venous acidosis associated with the use of these CO2generating buffers. (Crit Care Med 1998; 26:1397-1408)

ISSN:0090-3493    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

ObjectiveTo examine the utility of single-breath CO2analysis as a measure of lung volume.DesignA prospective, animal cohort study comparing 21 parameters derived from single-breath CO2analysis with lung volume measurements determined by nitrogen washout in animals during controlled ventilation.SettingAn animal laboratory in a university-affiliated medical center.SubjectsSeven healthy lambs.InterventionsThe single-breath CO2analysis station consists of a mainstream capnometer, a variable orifice pneumotachometer, a signal processor and computer software with capability for both on- and off-line data analysis. Twenty-one derived components of the CO2expirogram were evaluated as predictors of lung volume. Lung volume was manipulated by 3 cm H2O incremental increases in positive end-expiratory pressure from 0 to 21 cm H2O, and ranged between 147 and 942 mL.Measurements and Main ResultsFifty-five measurements of lung volume were available for comparison with derived variables from the CO2expirogam. Stepwise linear regression identified four variables that were most predictive of lung volume: a) dynamic lung compliance; b) the slope of phase 3; c) the slope of phase 2 divided by the mixed expired CO2tension; and d) airway deadspace. The multivariate Equation washighly statistically significant and explained 94% of the variance (adjusted r2= .94, p < .0001). The bias and precision of the calculated lung volume was.00 and 51, respectively. The mean percent difference for the lung volume estimate derived from the single-breath CO2analysis station was 0.79%.ConclusionsOur data indicate that analysis of the CO2expirogram can yield accurate information about lung volume. Specifically, four variables derived from a plot of expired CO2concentration vs. expired volume predict changes in lung volume in healthy lambs with an adjusted coefficient of determination of.94. Prospective application of this technology in the setting of lung injury and rapidly changing physiology is essential in determining the clinical usefulness of the technique. (Crit Care Med 1998; 26:1409-1413)

ISSN:0090-3493    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

ObjectiveTo determine whether endotoxin-stimulated alveolar macrophages would attract neutrophils and whether exogenous surfactant treatment would modulate this chemoattraction.DesignAlveolar macrophages were harvested from bronchoalveolar lavage fluid and neutrophils from the blood of anesthetized guinea pigs.SubjectsHartley guinea pigs.InterventionsAlveolar macrophages were suspended in RPMI 1640 and stimulated with 1 [micro sign]g/mL of lipopolysaccharide (LPS), the supernatant removed and the alveolar macrophages were incubated in either RPMI or RPMI with surfactant at two different doses (292 [micro sign]g/mL or 875 [micro sign]g/mL) for 16 hrs.Measurements and Main ResultsThe supernatant was extracted from the alveolar macrophages and placed in a chemotaxis plate and the migration of neutrophils was measured. Chemotaxis of all cell types to be tested was measured by a change of absorbance on a microplate reader set at 492 nm. Results were compared with alveolar macrophages not stimulated with LPS, RPMI alone, and N formyl-methionyl-leucyl-phenylalanine (FMLP).The supernatant of the stimulated alveolar macrophages increased neutrophil chemotaxis as compared with unstimulated alveolar macrophages, and RPMI (p < .05). Surfactant treatment with 292 [micro sign]g/mL significantly decreased LPS-stimulated alveolar macrophages induced neutrophil chemotaxis. Treatment with 875 [micro sign]g/mL of surfactant did not alter neutrophil chemotaxis.ConclusionsAlveolar macrophages stimulation with LPS increased the chemotaxis of neutrophils. Treatment with surfactant at a concentration of 875 [micro sign]g/mL did not alter neutrophil migration; however, treatment with 292 [micro sign]g/mL significantly decreased neutrophil chemotaxis suggesting that at low concentrations, surfactant inhibits chemokine release and may reduce pulmonary neutrophil sequestration in vivo. (Crit Care Med 1998; 26:1414-1418)

ISSN:0090-3493    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

ObjectiveTo evaluate the effect of severe head injury on both the secretion of basal pituitary hormones and the response to exogenous synthetic hypothalamic releasing factors administration.DesignProspective, clinical study.SettingGeneral intensive care unit in a university teaching hospital, Italy.PatientsComatose, head-injured patients (n = 22), all intubated and mechanically ventilated, invasively monitored without previous endocrinologic problems and substitutive therapies.InterventionsRoutine neuroemergency procedures; administration of exogenous, synthetic hypothalamic releasing hormones.Measurements and Main ResultsDeterminations of basal concentrations of growth hormone (GH), prolactin (PRL), thyroid-stimulating hormone (TSH), triiodothyronine, and thyroxine were performed daily in the first week and on days 15 and 16 after the trauma. Plasma insulin-like growth factor-I and cortisol were also determined on days 2, 7, and 15. We carried out a thyrotropin-releasing hormone (TRH) test for the evaluation of the PRL, TSH, and GH responses on days 1 and 16 after the trauma and a growth hormone-releasing hormone (GHRH) test for the evaluation of GH and PRL responses on days 2, 7, and 15 after the trauma. Outcome was evaluated at 6 mos with the GOS. Triiodothyronine showed low values, even if in the normal range; thyroxine remained in the normal range. Significant increases in insulin-like growth factor-I concentrations were observed on both days 7 and 15 compared with day 2 (p = .024 and p = .034, respectively). The GH response to GHRH was significantly greater on days 7 and 15 than in the very acute phase (p < .01 comparing days 7 and 15 vs. day 2). We found a higher GH response to GHRH on day 7 in group 1 vs. group 2 (as both peak and area under the curve, p = .018 and p = .015, respectively). No difference in GH response was detected on days 2 and 15. A "paradoxical" response of GH to TRH was observed on the day after the head trauma (basal vs. peak, p = .002) but not on day 16. The GH peak response to TRH was greater on day 1 in those patients with an unfavorable course (group 1 vs. group 2, p < .05). The TSH response to TRH was not significantly correlated to the severity of trauma, but it was significantly (p < .04) higher in group 1 than in group 2. Finally, a "paradoxical" PRL response to GHRH administration was present on day 2 (basal vs. peak, p = .0003), day 7 (basal vs. peak, p = .01), and on day 15 after the trauma (basal vs. peak, p = .04).ConclusionsSome of the responses to provocative tests have been identified as "paradoxical" and seem to have a great importance in the definition of prognosis in severe head-injured patients, specifically the GH response to TRH and the PRL response to GHRH that are significantly correlated with outcome. (Crit Care Med 1998; 26:1419-1426)

ISSN:0090-3493    

出版商:OVID    

年代:1998

数据来源: OVID