摘要:

ObjectiveTo assess the short-term effects of extending inspiratory time by lengthening end-inspiratory pause (EIP) without inducing a clinically significant increase in intrinsic positive end-expiratory pressure (PEEPi) in patients with acute respiratory distress syndrome (ARDS).DesignControlled, randomized, crossover study.SettingTwo medical intensive care units of university hospitals.PatientsSixteen patients with early (≤48 hrs) ARDS.InterventionWe applied two durations of EIP (0.2 secs and extended) each for 1 hr while keeping all the following ventilatory parameters constant: Fio2, total PEEP (PEEPtot = applied PEEP + PEEPi), tidal volume, inspiratory flow, and respiratory rate. The duration of extended EIP was titrated to avoid an increase of PEEPi of ≥1 cm H2O.Measurements and Main ResultsDespite an increase in mean airway pressure (20.6 ± 2.3 vs. 17.6 ± 2.1 cm H2O,p< .01), extended EIP did not significantly improve Pao2(93 ± 21 vs. 86 ± 16 torr [12.40 ± 2.80 vs. 11.46 ± 2.13 kPa] with 0.2 secs EIP, NS). However, although the difference in Pao2between the two EIP durations was <20 torr (<2.66 kPa) in 14 patients, two patients exhibited a >40 torr (>5.33 kPa) increase in Pao2with extended EIP. Extended EIP decreased Paco2(62 ± 13 vs. 67 ± 13 torr [8.26 ± 1.73 vs. 8.93 ± 1.73 kPa] with 0.2 secs EIP,p< .01), which resulted in a higher pH (7.22 ± 0.10 vs. 7.19 ± 0.09 with 0.2 secs EIP,p< .01) and contributed to a slight increase in arterial hemoglobin saturation (94 ± 3 vs. 93 ± 3% with 0.2 EIP,p< .01). No significant difference in hemodynamics was observed.ConclusionIn patients with ARDS, extending EIP without inducing a clinically significant increase in PEEPi does not consistently improve arterial oxygenation but enhances CO2elimination.

ISSN:0090-3493    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveTo refine the prognosis of critically ill patients using a statistical model that incorporates the daily probabilities of hospital mortality during the first week of stay in the intensive care unit (ICU).DesignProspective inception cohort.SettingFifteen adult medical and surgical ICUs in Spain.PatientsA total of 1,441 patients aged ≥18 yrs who were consecutively admitted from April 1, 1995, through July 31, 1995.InterventionsProspective data collection during the stay of the patient in the ICU. Data collected included vital status at hospital discharge as well as all variables necessary for computing the Mortality Probability Models II system at admission and during the first 7 days of stay in the ICU.Measurements and Main ResultsFour logistic regression models were obtained. These models contained survival status at hospital discharge as a dependent variable and the following explanatory variables: (model 1) only the probability of dying at admission; (model 2) only the probability of dying during the current day; (model 3) the probability of dying at admission and during the current day; and (model 4) the probabilities of dying at admission and during the previous and current days.Models were evaluated using the Hosmer-Lemeshow statistic and the area under the receiver operating characteristic curve. For survivor and nonsurvivor patients, mortality probabilities obtained using the aforementioned models were compared using linear regression and the paired Student’st-test.Although severity at admission was a statistically significant variable, models 2 and 3 produced almost the same probabilities of hospital mortality, as shown with the linear regression and paired Student’st-test results.ConclusionsTo have an accurate measurement of the prognosis, it is necessary to update the severity measure. The best estimate of hospital mortality was the probability of death on the current day. Severity at admission and at previous days did not improve the assessment of prognosis.

ISSN:0090-3493    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveTo compare prone positioning and continuous rotational therapy with respect to oxygenation and hemodynamics in patients suffering from adult respiratory distress syndrome (ARDS).DesignRandomized, prospective pilot study.SettingIntensive care unit at a university hospital.PatientsTwenty-six mechanically ventilated patients with ARDS from nontraumatic causes.InterventionsTwelve patients were turned prone (group 1), 14 patients underwent continuous axial rotation from one lateral position to the other with a maximum angle of 124 degrees in specially designed beds (group 2). All patients had received inhaled nitric oxide (NO) therapy before positioning.Measurements and Main ResultsGas exchange and hemodynamics were assessed using a pulmonary artery catheter. In both groups, an improvement in Pao2/Fio2-ratio and intrapulmonary shunt fraction occurred after initiation of NO as well as during the first 72 hrs of positioning therapy. During the study period, seven patients died in group 1 and nine patients in group 2 (p= NS). Comparing the areas under the curve during the first 72 hrs, no significant differences with respect to Pao2/Fio2-ratio, Paco2, positive end-expiratory and peak inspiratory pressure levels, intrapulmonary shunt fraction, the alveolar-arterial oxygen difference, and oxygen delivery and consumption, as well as cardiac index, pulmonary and arterial blood pressures, and pulmonary arterial occlusion pressure could be detected between the groups. Prone positioning was tolerated well, continuous rotational therapy had to be modified according to hemodynamic instability in three patients.ConclusionsIn severe lung injury, continuous rotational therapy seems to exert effects comparable to prone positioning and could serve as alternative when prone positioning seems inadvisable.

ISSN:0090-3493    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectivesTo examine the hypothesis that the response to inhaled prostacyclin (PGI2) on oxygenation and pulmonary hemodynamics may be related to different morphologic features that are supposed to be present in acute respiratory distress syndrome (ARDS) originating from pulmonary (primary ARDS [ARDSPR]) and from extrapulmonary disease (secondary ARDS [ARDSSEC]).DesignProspective, nonrandomized interventional study.SettingMultidisciplinary intensive care unit, secondary care center.PatientsFifteen consecutive, mechanically ventilated patients with ARDS and severe hypoxemia, defined as Pao2/Fio2of <150 torr at the time of admission.InterventionsAfter an initial stable period of at least 60 mins, patients received nebulized PGI2in 15-min steps; the drug was titrated to find the dose with the best improvement of Pao2, starting with 2 ng/kg/min up to an allowed maximum dose of 40 ng/kg/min.Measurements and Main ResultsBlood gas, gas exchange, and hemodynamic measurements were performed at the following time points: a) baseline; b) during the optimal or maximum dose of PGI2; and c) 1 hr after withdrawal of the drug. Patients underwent a computed tomographic (CT) scan using a basal CT section to compute the mean CT numbers and the density histogram. Patients were considered responders to PGI2if an increase in Pao2of ≥7.5 torr or an increase in Pao2/Fio2ratio of ≥10% occurred. For the group as a whole, mean pulmonary artery pressure decreased from 32 ± 1 to 29 ± 1 mm Hg during PGI2nebulization, whereas pulmonary vascular resistance decreased 1 hr after withdrawal of nebulization from 177 ± 18 to 153 ± 16 dyne·sec/cm5; oxygenation did not change significantly. Eight patients responded to PGI2nebulization on oxygenation (all were in the ARDSSEC subgroup), whereas seven did not (all but one were in the ARDSPR subgroup). Among the physiologic variables examined to assess any difference between the two ARDS groups at time of PGI2nebulization, there was a significant difference concerning the mean CT density number, which was −445 ± 22 Hounsfield Units in the ARDSSECgroup and −258 ± 16 Hounsfield Units in the ARDSPRgroup. In patients presenting with an ARDSPR, PGI2induced a reduction in Pao2/Fio2and a reduction in Pao2from 87 ± 2 to 79 ± 2 torr, whereas in patients with an ARDSSECthere was an increase in Pao2/Fio2and in Pao2from 76 ± 4 to 84 ± 4 torr with a decrease in mean pulmonary artery pressure.ConclusionsBased on the data from this study, the clinical recognition of the two types of the syndrome together with the CT number frequency distribution analysis may be associated with a prediction of the PGI2nebulization response on oxygenation.

ISSN:0090-3493    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveTo investigate whether marker(s) of systemic inflammation detect, at an early stage of acute pancreatitis, patients who may ultimately develop severe disease.DesignProspective study.SettingUniversity hospital emergency unit.PatientsThirty patients with mild acute pancreatitis (SEV0group) and 27 with severe acute pancreatitis. Of the latter, 11 did not develop organ failure (SEV1group), whereas the other 16 patients developed acute respiratory failure and 9 of them also developed renal failure (SEV2group).InterventionsBlood samples were collected at admission to the hospital (T0), and at 12 hrs (T12) and 24 hrs (T24) after admission.Measurements and Main ResultsThe plasma concentrations of procalcitonin (PCT), soluble E-selectin (sE-selectin), soluble interleukin-2 receptor (sIL-2R), and the serum concentration of C-reactive protein (CRP) were monitored. PCT levels at T0were significantly higher in the SEV1group (median 0.4 ng/mL, range 0.2–2.3) and the SEV2group (0.8 ng/mL, 0.2–73.5) than in the SEV0group (0.3 ng/mL, 0.1–3,p< .05 andp< .001, respectively). At T12, PCT level in the SEV2group was significantly higher than that in the SEV1group (2.2 ng/mL, 0.2–86.6 vs. 0.4 ng/mL, 0.3–2.8,p= .05), as it also was at T24(2.2 ng/mL, 0.4–73.3 vs. 0.5 ng/mL, 0.3–4,p< .01). Among SEV2patients, PCT concentration correlated negatively with the time elapsed between admission and the diagnosis of organ failure. At T12, sIL-2R levels of the SEV1group (1011 U/mL, range 334–2211) and the SEV2group (1495 U/ml, range 514–4526) both differed significantly from the SEV0group (636 U/ml, range 356–1678,p< .05 andp< .001, respectively) as they also did at T24. Although CRP level in the SEV1group at T12did not differ from the SEV0group, the difference between SEV2(272 &mgr;g/mL, range 46–462) and SEV0was significant (53 &mgr;g/mL, range 5–243,p< 0.01). sE-selectin levels did not differ between groups.ConclusionsAt admission to hospital, concentrations of PCT, but not those of CRP, sE-selectin, or sIL-2R, are higher in patients with severe acute pancreatitis than in patients with mild pancreatitis. PCT test had sensitivity of 94% and specificity of 73% for development of organ failure. PCT may be useful to identify the patients who benefit from novel therapies aimed at modifying the course of systemic inflammation.

ISSN:0090-3493    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveTo study the value of gastric intramucosal pH and gastric intraluminal Pco2measurements to predict weaning outcome from mechanical ventilation.DesignProspective clinical study.SettingIntensive care medicine department of a university hospital.PatientsNineteen adult critically ill patients who were mechanically ventilated because of acute respiratory failure and were considered ready to be weaned.InterventionsThe patients were weaned with: synchronized intermittent mandatory ventilation plus positive end-expiratory pressure (SIMV+PEEP) or continuous positive airway pressure with pressure support ventilation (CPAP+PSV). A gastric tonometer was placed in all the patients. Tonometric, respiratory, and hemodynamic variables were measured during the weaning process.MeasurementsHemodynamic variables, respiratory mechanics, pulmonary gas exchange, respiratory muscle force, spontaneous pattern of breathing, and the central control of breathing were recorded. Simultaneously, the intramucosal pH and gastric intraluminal Pco2were measured.Main ResultsEleven patients were successfully extubated and eight failed. The patients who failed showed higher values of mouth occlusion pressure, respiratory rate, and effective inspiratory impedance (mouth occlusion pressure/mean inspiratory flow). The intramucosal pH was initially 7.19 ± 0.22 and decreased to 7.10 ± 0.16 during the weaning process in patients who failed (p< .05). At the same time, the intramucosal pH showed a nonsignificant change from 7.36 ± 0.07 to 7.32 ± 0.07 in the patients who were successfully extubated. The intramucosal pH was statistically different when both groups were compared during the initial and the final evaluations (p< .05). For the initial evaluation, the sensitivity and specificity to predict weaning failure when the intramucosal pH was ≤7.30 were 0.88 (95% confidence interval [CI], 0.66–1) and 0.82 (95% CI, 0.59–1), respectively. The gastric intraluminal Pco2was higher in patients who failed (p< .05). When gastric intraluminal Pco2was ≥40 torr during the initial evaluation, weaning failure occurred with a sensitivity of 1 (95% CI, 0.31–1) and a specificity of 0.55 (95% CI, 0.26–0.84).ConclusionsWeaning failure was associated with gastric intramucosal acidosis. The intramucosal pH and gastric intraluminal Pco2may be helpful to predict weaning outcome. Further controlled clinical trials in a larger group of patients are needed.

ISSN:0090-3493    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveTo measure cerebrospinal fluid and plasma concentrations of nitrate and nitrite as indicators of nitric oxide production in adults after subarachnoid hemorrhage (SAH).DesignA prospective, clinical study.SettingMultidisciplinary intensive care unit.PatientsNine patients (three males and six females, aged 29-64 yrs) with aneurysm-induced SAH were studied. Glasgow Coma Scale score on admission ranged from 9 to 15. Ruptured aneurysms were clipped within 72 hrs of ictus, and then conventional hypervolemic, hemodilution, and induced hypertension methods were applied.InterventionsNone.Measurements and Main ResultsNitrate and nitrite concentrations of patients were examined sequentially by a capillary zone electrophoresis every day for 13 days. As a control group, cerebrospinal fluid was sampled from patients (n = 9, six males and three females, aged 30-60 yrs) without neurologic disorders who underwent spinal taps for spinal anesthesia, and plasma from healthy human volunteers (n = 43, 21 males and 22 females, aged 23-49 yrs). There were no significant differences over time in cerebrospinal fluid nitrate concentrations after SAH. Concentrations of cerebrospinal fluid nitrate after SAH were increased compared with control values. Plasma nitrate concentration was decreased compared with control values, but the value on day 14 was increased significantly (p< .05) compared with those during days 2–11. Plasma and cerebrospinal fluid nitrite concentrations after SAH were similar to those in control subjects. Similar concentrations of nitric oxide metabolite in plasma and cerebrospinal fluid were observed between the patients with and without symptomatic vasospasm.ConclusionThe increase of cerebrospinal fluid nitrate after SAH may attribute to the endogenous nitric oxide production in the injured brain.

ISSN:0090-3493    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveTo assess the value of &agr;-atrial natriuretic peptide (&agr;-ANP), second messenger cyclic guanosine monophosphate (cGMP,) and endothelin as markers of myocardial depression in septic shock.DesignProspective observational study.SettingMedical intensive care unit (ICU) of a university hospital.PatientsFourteen consecutive patients with septic shock and arterial and pulmonary artery catheters in place.Measurements and Main ResultsHemodynamic variables and plasma levels of &agr;-ANP, cGMP, and endothelin were measured every 6 hrs for 3 days after admission. Eight patients died from shock in the ICU. The nadir left ventricular stroke work index (LVSWI) was below 35 g/m2in all patients, and the median peak circulating &agr;-ANP (n < 68 pg/mL) was 276 pg/mL (range, 79–1056), the median peak cGMP (n < 2.1 ng/mL) was 8.1 ng/mL (range, 3.2–29.7), and the median peak endothelin (n < 5.3 pg/mL) was 15.5 pg/mL (range, 8.5–33.9), supranormal in all patients. Outcome groups differed in the course of cardiac index and LVSWI, which were lower in nonsurvivors despite similar filling pressures and more intensive inotropic treatment (p< .01). The course of &agr;-ANP, cGMP, and endothelin plasma levels also differed between groups, with higher levels in nonsurvivors (p< .05). As for pooled data, the mean daily or nadir LVSWI inversely related to mean daily or peak &agr;-ANP, cGMP, and endothelin levels, respectively (p< .05). The area under the receiver operating characteristic curve for myocardial depression (LVSWI < 35 g/m2) was for &agr;-ANP and endothelin 0.77, and for cGMP 0.85 (p< .01). The optimum cutoff values for &agr;-ANP, cGMP, and endothelin were 172 pg/mL, 4.5 ng/mL, and 10.0 pg/mL, respectively. The sensitivity for myocardial depression of &agr;-ANP, cGMP, and endothelin was 68%, 77%, and 72%, and the specificity was 82%, 93%, and 69%, respectively.ConclusionsCirculating &agr;-ANP, endothelin, and, particularly, cGMP may be markers of the myocardial depression of human septic shock, which is associated with mortality.

ISSN:0090-3493    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveGastric intramucosal Pco2(Pico2) and pH (pHi) are currently used as indices of the adequacy of splanchnic perfusion and as end points to guide therapeutic intervention. However, little is known about their spontaneous variability over time. The present study was designed to define the magnitude of spontaneous variability of Pico2and pHi in sedated medical intensive care unit (ICU) patients using an automated recirculating air tonometer and to test whether high-level positive end-expiratory pressure (PEEP) or inverse inspiratory/expiratory (I:E) ratio ventilation resulted in a greater variability than low PEEP with conventional I:E ratio ventilation.DesignProspective study.SettingMedical ICU in a tertiary medical center.PatientsTwenty-three acute respiratory failure patients.InterventionsAfter being sedated, patients were randomized to undergo pressure control ventilation at the following three settings: A, high PEEP (15 cm H2O) with conventional I:E ratio (1:2), and B, low PEEP (5 cm H2O) with inverse I:E ratio (2:1) alternately, and then C, low PEEP (5 cm H2O) with conventional I:E ratio (1:2). Each ventilation setting period lasted 1 hr.Measurements and Main ResultsThe Pico2and pHi were measured at baseline (time 0), and at 15, 30, 45, and 60 mins thereafter. The corresponding coefficients of variation (CVs) of Pico2for overall pooled group and settings A, B, and C were 4.0%, 4.4%, 3.4%, and 4.2%, respectively. The corresponding CVs of pHi for overall pooled group and settings A, B, and C were 0.36%, 0.37%, 0.33%, and 0.4%, respectively. Analysis of variance showed no significant difference in the CVs of Pico2or pHi between the three settings. The 95% confidence interval is approximately ±8% variability for Pico2and ±0.7% variability for pHi.ConclusionsIn critically ill medical ICU patients with stable hemodynamics, the spontaneous variability of Pico2or pHi are not substantial. High PEEP (15 cm H2O) and inverse ratio ventilation (2:1), which does not change the cardiac output or hemodynamics, does not contribute to increased spontaneous variability in Pico2or pHi.

ISSN:0090-3493    

出版商:OVID    

年代:2001

数据来源: OVID