摘要:

ObjectivesControversy exists regarding the ideal injectate temperature for measuring cardiac output. Iced temperature injectate gives a higher signal/noise ratio and less variability in the measured cardiac output. Thus, less volume and fewer measurements are required. Advocates of room temperature injectate have suggested that iced temperature injectate may perturb cardiodynamics. This concern has remained largely untested. To help resolve this controversy, we examined the effects of 5 mL iced injectate (0 degree C to 4 degrees C) infusions on cardiodynamics.DesignProspective, randomized, controlled study.SettingA critical care research laboratory.SubjectsFive domestic pigs, weighing between 20 to 25 kg.InterventionsUnder barbiturate anesthesia, pigs underwent placement of a) a thermodilution catheter in the right internal jugular vein; b) a right carotid artery catheter for mean arterial pressure; and c) sonomicrometry crystals for dynamic measurements of left ventricular dimensions. Calculations were made of end-systolic and end-diastolic left ventricular volume and ejection fraction. Six cardiac output measurements were performed in each pig. Data were obtained at baseline (just before iced temperature injectate infusion) and every 3 secs for 9 secs.Measurements and Main ResultsThe only significant effect seen with iced temperature injectate infusion was a small, transient decrease in heart rate (minus 5.9 plus minus 1.1 beats/min from a baseline heart rate of 144.8 plus minus 20.6 beats/min). Indices of preload, contractile function, and dynamic cardiac geometry were unaffected.ConclusionsIced temperature injectate used in clinically relevant volumes causes transient negative chronotropic effects, but reservations regarding other perturbations of cardiodynamics are unfounded. Thus, the use of iced temperature injectate for cardiac output determination is still a viable alternative to room temperature injectate use, especially when a larger signal/noise ratio is required.(Crit Care Med 1996; 24:495-500)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectiveTo investigate the effects of the availability of daily patient-related charges to healthcare providers on practice patterns and cost containment in the pediatric intensive care unit (ICU) setting.DesignProspective, nonrandomized, controlled trial.SettingPediatric ICU.PatientsAll patients admitted to the pediatric ICU during the study period. This number included a prospective control group (n equals 325) and an intervention group (n equals 273). These 598 patients spent 2,274 patient days in the pediatric ICU.InterventionsThe daily itemized patient charges related to diagnostic studies ordered in the pediatric ICU were made available to healthcare providers during the intervention period of the study.Measurements and Main ResultsInformation was collected prospectively on patients in the control group before the intervention period. This information included data on demographics, daily severity of illness measures, daily resource consumption, intensity of nursing and medical interventions, and daily patientrelated charges. Outcome information on survival and length of pediatric ICU stay was also collected. The same data were collected prospectively during the intervention period of the study. Measurements on quality assurance and morbidity were made to ensure that there was no compromise in patient care. There were no significant differences in patient demographics and diagnoses between the control and intervention groups. There was a reduction in the average daily laboratory (16.7%), radiology (9.1%), computerized axial tomography (8.5%), and pharmacy (25.1%) charges in the intervention group as compared with controls. The decreases in laboratory and pharmacy charges were statistically significant (p less than .0001). The decreases in laboratory and pharmacy charges remained significant even after adjustment for severity of illness.ConclusionsThe availability of patient-related charges to healthcare providers can result in changes in practice patterns, producing a decrease of patient charges and an improvement in cost containment in the pediatric ICU.(Crit Care Med 1996; 24:501-506)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectivesTo assess the accuracy of pulse oximetry under hypothermic conditions in neonates and infants undergoing cardiac surgery, and to assess the effect of probe site as well as probe site skin temperature on the reliability of pulse oximetry.DesignProspective study.SettingCardiac operating room and intensive care unit of a children's hospital.PatientsTwenty-five infants less than 3 months of age undergoing cardiac surgery with cardiopulmonary bypass.InterventionsPulse oximeter readings (SpO2) from probes placed on the hand and foot were recorded at various skin temperatures and compared with hemoximeter oxygen saturations (SaO2) obtained on simultaneously drawn arterial blood samples. Core temperature, arterial pressure and vasodilator use were recorded simultaneously.Measurements and Main ResultsPulse oximetry bias (SpO2-SaO2) increased to an unacceptable range (more than plus 3% or less than minus 3%) in 45.5% of the readings at foot probe site temperatures of less than equals 27 degrees C. Pulse oximetry bias was within an acceptable range in 94.7% of the readings at temperatures more than 29 degrees C. There was no significant difference between oximeter readings obtained from two probe sites (hand and foot). Administration of phenoxybenzamine improved the accuracy of pulse oximetry in ten infants at skin temperature of less than 27 degrees C.ConclusionsPulse oximetry readings in small infants are likely to be unreliable at skin temperatures of less than 27 degrees C, irrespective of probe site. Intravenous phenoxybenzamine appeared to improve the accuracy of pulse oximetry at low temperatures.(Crit Care Med 1996; 24:507-511)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectiveTo compare a phosphate buffered solution with normal saline as tonometric fluid in intramucosal PCO2measurement in humans.DesignProspective, unblinded comparison.SettingPostsurgical critical care unit of a university hospital.PatientsSix septic patients.InterventionsTwo tonometric probes were positioned in the gastric lumen in each patient. One tube was used for conventional tonometry (saline-filled balloon), while phosphate buffered solution was instilled into the second tube.Measurements and Main ResultsPCO2was determined with three blood gas analyzers (ABL 2 [Radiometer, Copenhagen, Denmark], Corning 288 [Ciba Corning Diagnostics GmbH, Neuss, Germany], and StatProfile 9 Plus [Nova Biomedical, Waltham, MA]). Eight parallel PCO2measurements per patient were evaluated, yielding a total of 48 measurements with each tonometric solution.Intrainstrumental comparison of the PCO sub 2 determinations demonstrated an increase of 12.3 plus minus 9.9% for ABL 2, 31.0 plus minus 12.9% for Ciba Corning 288, and 101.2 plus minus 31.5% for StatProfile 9 Plus with the phosphate buffered solution. The PCO2values were decreased by the following amounts when the three instruments were compared, using the saline method: 14.2 plus minus 8.2% (Ciba Corning 288 vs. ABL 2); 40.7 plus minus 9.9% (StatProfile 9 Plus vs. ABL 2); and 30.9 plus minus 9.35% (StatProfile 9 Plus vs. Ciba Corning 288).The difference in PCO sub 2 determination, resulting from the different instrument designs, were significant between the three blood gas analyzers (p less than .001). In addition, the variance of the intramucosal PCO2values was significant between blood gas analyzers (p less than .001) with normal saline as tonometric solution, but not with phosphate buffered solution.The coefficients of determination between PCO sub 2 values in saline and phosphate buffered solution were r sup 2 equals .85 for ABL 2, r2equals .81 for Ciba Corning 288, and r2equals .74 for StatProfile 9 Plus. When all 48 PCO2values were analyzed, the interinstrumental coefficients of determination within a method for saline (and for phosphate buffered solution in parentheses) were: r sup 2 equals .83 (.92) between ABL 2 and Ciba Corning 288, r2equals .72 (.92) between ABL 2 and StatProfile 9 Plus, and r2equals .81 (.98) between Ciba Corning 288 and StatProfile 9 Plus.ConclusionsA considerable instrumental bias in PCO2analysis is observed when saline is used as tonometric fluid in gastric tonometry, thus preventing a reliable determination of intramucosal pH. The present in vivo data show that the accuracy and reliability of intramucosal pH measurement can be improved by the use of phosphate buffered solution as tonometric fluid.(Crit Care Med 1996; 24:512-516)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectiveTo systematically review the effect of interventions designed to achieve supraphysiologic values of cardiac index, oxygen delivery (DO2), and oxygen consumption (VO2) in critically ill patients.Data SourcesComputerized bibliographic search of published research, citation review of relevant articles, and contact with primary investigators.Study SelectionWe included all randomized clinical trials of adult intensive care unit (ICU) patients that evaluated interventions (fluids, inotropes, and vasoactive drugs) designed to achieve supraphysiologic values of cardiac index, DO2, and/or VO2. Independent review of 64 articles identified seven relevant studies of 1,016 patients.Data ExtractionWe abstracted data on the population, interventions, outcomes, and methodologic quality of the studies by duplicate independent review. Agreement was high (weighted kappa 0.73); differences were resolved by consensus.Data SynthesisTargeting therapy to achieve supraphysiologic end points in critically ill patients is associated with a nonstatistically significant trend toward decreased mortality rates (relative risk 0.86, 95% confidence intervals 0.62 to 1.20). For the two studies in which supraphysiologic goals were initiated preoperatively, the relative risk was 0.20 (95% confidence intervals 0.07 to 0.55). This value differed significantly from the combined estimate of the remaining studies, in which the intervention was started after ICU admission (relative risk 0.98, 95% confidence intervals 0.79 to 1.22; p less than .01). However, there are several methodologic problems with the primary studies. In no trials were caregivers or outcome assessors blinded to treatment allocation. Only three of seven trials analyzed patients according to the group to which they were allocated. None adequately controlled for cointerventions, and there was considerable crossover between groups (patients in the control group achieved the goals of the intervention group and vice versa).ConclusionsInterventions designed to achieve supraphysiologic goals of cardiac index, DO2, and VO2did not significantly reduce mortality rates in all critically ill patients. However, there may be a benefit in those patients in which the therapy is initiated preoperatively. Methodologic limitations weaken the inferences that can be drawn from these studies and preclude any evidence-based clinical recommendations.(Crit Care Med 1996; 24:517-524)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectivesTo review the literature on the current use of vasopressors and inotropes in patients with sepsis and sepsis syndrome with respect to the choice of agent, therapeutic end points, and safe and effective doses to be used. To examine the available evidence that supports or refutes goal-directed therapy toward supranormal oxygen transport in optimizing the outcome of critically ill sepsis syndrome patients.Data SourcesAll pertinent English and French articles dealing with hemodynamic support with selected vasopressors and inotropic agents in human sepsis and sepsis syndrome retrieved from a computerized MEDLINE search from 1985 to 1994.Study SelectionClinical studies with norepinephrine, epinephrine, phenylephrine, dopamine, and dobutamine in sepsis syndrome were considered if goal-directed therapy with oxygen transport variables was utilized. Emphasis was placed on prospective, randomized, controlled comparative trials. However, openlabel, observational, and comparative studies, or case series, were also evaluated when limited data were available.Data ExtractionFrom the selected studies, information was obtained regarding patient population, dosing regimen, type of therapeutic goals or end points (hemodynamic, or normal vs. supranormal oxygen transport variables) and outcome data (e.g., achievement of goals, resolution of the episode, mortality rate, and development of end-organ dysfunction).Data SynthesisWhen used in larger than usual doses, epinephrine, norepinephrine, and phenylephrine uniformly increased hemodynamic values. Epinephrine may increase oxygen transport values more reliably than norepinephrine. Dobutamine doses in the range of 2.5 to 6 micro gram/kg/min increase oxygen transport variables and hemodynamics to predetermined goals in only 30% to 70% of patients. Larger infusion rates offer no further benefits.ConclusionsInsufficient evidence exists to support goal-directed therapy with vasopressors and inotropes in the treatment of sepsis syndrome. No definitive recommendations can be made about the superiority of a vasopressor or inotropic agent due to the lack of data. However, it may be that evaluation of vasopressors earlier in sepsis syndrome will yield more promising results. Large, comparative, controlled trials assessing mortality rate and development of multiple organ system dysfunction are needed.(Crit Care Med 1996; 24:525-537)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

ObjectiveTo describe the occurrence of low measured auto-end-expiratory pressure (auto-PEEP) during mechanical ventilation of patients with severe asthma.DesignObservational clinical study.SettingMedical intensive care unit of a university-affiliated county hospital.PatientsFour mechanically ventilated patients with severe asthma who had low measured auto-PEEP despite marked increase in both peak and plateau airway pressures.InterventionsNone.Measurements and Main ResultsPeak pressure, plateau pressure, and auto-PEEP were measured at an early time point, when airflow obstruction was most severe, and again at a later time after clinical improvement. Auto-PEEP was measured by the method of end-expiratory airway occlusion. From the early to the late time point, there was a marked decrease in peak pressure (76 plus minus 7 to 53 plus minus 6 cm H2O; p less than .001) and in plateau pressure (28 plus minus 2 to 18 plus minus 3 cm H2O; p less than .001), but only minimal change in auto-PEEP (5 plus minus 3 to 4 plus minus 3 cm H2O). The difference between plateau pressure and auto-PEEP decreased between the early and late time points (23 plus minus 1 to 14 plus minus 1 cm H2O; p less than .01), even though tidal volume was larger at the late time point. In three patients, low auto-PEEP and a large difference between plateau pressure and auto-PEEP was only seen after expiratory time was prolonged. In these three patients, prolongation of expiratory time resulted in a large decrease in measured auto-PEEP (14 plus minus 4 to 5 plus minus 4 cm H2O), but a much smaller change in plateau pressure (31 plus minus 3 to 29 plus minus 3 cm H2O).ConclusionsWe conclude that measured auto-PEEP may underestimate end-expiratory alveolar pressure in severe asthma, and that marked pulmonary hyperinflation may be present despite low measured auto-PEEP, especially at low respiratory rates. This phenomenon may be due to widespread airway closure that prevents accurate assessment of alveolar pressure at end-expiration.(Crit Care Med 1996; 24:541-546)

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1996

数据来源: OVID