摘要:

ObjectiveTo compare a solution of 3% dextran-60 (D60) in Ringer's lactate (RL) with RL alone as maintenance fluids for abdominal aortic surgery.DesignRandomized control trial of 20 consecutive patients undergoing elective aortic reconstructive surgery.SettingA surgical ICU in a university hospital.PatientsConsecutive patients, mean age 64 yr. Five patients had abdominal aneurysm, 12 had aortic obstruction disease, and three had aortic renal bypass surgery. These patients were followed for 1 month.InterventionsPulmonary artery occlusion pressure of at least 10 mm Hg and a urine output >30 mL/h were used to guide the intraoperative fluid infusion rates, which were 36 and 104 mL/kg of D60 and RL, respectively (ratio 1:2.9).Measurements and Main ResultsBody weight at 24 hr had increased more with RL (7.8 kg) than with D60 (3.2 kg) infusion (p< .01), despite intraoperative urine volumes of 151 and 92 mg/kg with RL and D60, respectively. Total intravascular albumin decreased from 0.7 g/kg (1.4 to 0.7 g/kg) in both groups, corresponding to a plasma volume (PV) loss of 13 mg/kg without fluid infusions. A total intravascular dextran of 0.5 g/kg resulted in a PV expansion at 1 hr of 4.4 mL/kg above preoperative level, in sharp contrast to 7.0 mL/kg decrease in PV with RL. Of the intraoperative 3% D60 and RL infused, an estimated 51% D60 and 6% RL remained as PV expansion at 1 hr.ConclusionA diluted colloid solution in Ringer's lactate is of significant value in maintaining intravascular volumes and hemodynamics during and after major operative procedures. (Crit Care Med 1991; 19:36)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectiveThe aim of the study was to estimate the influence of therapeutic changes on the level of energy expenditure (EE) and N excretion in a homogeneous group of patients usually considered hypermetabolic.DesignEE and N excretion of head-injured patients were measured simultaneously at phases 1 and 2 (patients treated 4 ± 3 and 18 ± 8 days after injury, respectively).SettingAcute care hospital.PatientsEight severe head-injured patients, mean weight 63.1 ± 6.1 (SD) kg, mean age 21 ± 3.8 (SD) yr.InterventionsAt phase 1, all patients were sedated with fentanyl (6.7 ± 1.9 μg/kg·hr) plus flunitrazepam (9.1 ± 4.8 μg/kg·hr) and were mechanically ventilated. All patients received continuous total parenteral nutrition. The nonprotein caloric intake averaged 1092 ± 200 kcal/day, including 77% glucose and 23% fat (Intralipid 20%). The total N intake averaged 7 ± 5 g/day, consisting of crystalline amino acids. At phase 2, no patient received any sedative and all were breathing spontaneously via tracheostomy. All patients received parenteral and/or enteral nutrition. The nonprotein caloric intake averaged 1929 ± 200 kcal/day consisting of 65% carbohydrates and 35% fat. The total N intake averaged 13 ± 2 g/day.Measurements and Main ResultsThe EE was significantly higher at phase 2 than at phase 1 (2121 vs. 1737 kcal), but the interindividual variability was low at both phases. N excretion was high at the two periods of the study and not correlated to the level of EE. The RQ was 0.75 at both periods, indicating predominant fat oxidation.ConclusionWe could not demonstrate any parallelism in the evolution of EE and protein catabolism in head-injured patients. The therapeutics (mechanical ventilation, sedation, and nutrition) have a major effect on EE but little on N excretion. (Crit Care Med 1991; 19:43)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Objectivesa) To determine the variation in methods used to measure minute ventilation (VE) in patients who receive mechanical ventilation; b) to determine the effect of supplemental oxygen on Ve, respiratory rate (RR), and tidal volume (VT) measurements.DesignTelephone survey of hospitals, and a randomized control trial.SettingMedical and surgical ICUs in a university hospital.PatientsThirty-three patients who had required mechanical ventilation because of the inability to sustain adequate spontaneous ventilation. All patients were considered ready to undergo a weaning trial by their physicians.InterventionsSpontaneous VE, RR, VT, and Sao2were measured both in the presence and absence of supplemental oxygen; measurements were obtained in a randomized manner.Measurements and Main Resultsa) In a telephone survey of hospitals throughout the country, we found that the measurement of VE is variably obtained during room air breathing or in the presence of supplemental oxygen. b) Measurements of VE increased from 11.0 ± 0.8 L/min while patients received supplemental oxygen to 13.5 ± 1.1 L/min while patients breathed room air (p< .001). Of 15 patients who had a VE <10 L/min while receiving supplemental oxygen, seven developed a value >10 L/min while breathing room air; thus, a weaning trial might have been inappropriately deferred in these patients. c) Mean Sao2decreased from 95.0 ± 0.6% while breathing supplemental oxygen to 90.2 ± 1.1% while breathing room air (p < .001).ConclusionMeasurements of VE in patients being considered for a weaning trial can result in significant oxygen desaturation if obtained during room air breathing, and the values obtained can significantly overestimate the patient's true ventilatory requirements, since most patients receive supplemental oxygen during a weaning trial. Standardized methods of measuring VE in critically ill patients need to be developed. (Crit Care Med 1991; 19:49)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectivesTo determine the effect of total parenteral nutrition (TPN) and different enteral feeding formulas on survival and liver function following hemorrhage in rats.DesignProspective randomized controlled study.SettingLaboratory of a large university-affiliated medical school.SubjectsSixty-seven male Sprague-Dawley rats weighing 350 to 450 g.InterventionsJugular and gastroduodenal feeding catheters were inserted in animals 1 day before hemorrhage, and animals were started on one of six different fluid or nutritional regimens: TPN, iv saline, an enteral amino acid-based formula (AA) (Vivonex-TEN), an enteral peptide-based formula (PEP) (Reabilan-HN), an enteral intact-protein based formula (PRO) (Osmolite-HN), or enteral saline. A catheter was inserted in the tail artery and animals were hemorrhaged 5 mL/kg at baseline and 1 hr later. Animals were returned to their cages and observed for survival. Liver function was determined by measuring circulating bile acid levels at baseline and 24 hr after hemorrhage.Measurements and Main ResultsMortality was significantly increased in animals receiving TPN (63%) and AA (24%). Mortality was 13% in animals receiving PRO and 0% in animals receiving PEP and saline. Liver function deteriorated in all animals after hemorrhage except the PEP group.ConclusionTPN and AA increased mortality in animals after hemorrhage. PEP was associated with zero mortality and protection of liver function after hemorrhage. (Crit Care Med 1990; 19:54)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Background and MethodsWe compared the hemodynamic effects of four vasodilators in experimental embolic pulmonary hypertension in a randomized controlled trial, using nine pigs weighing 16 to 23 kg. After anesthesia induction and cannulation with arterial, central venous, and thermodilution output pulmonary artery catheters, animals were repetitively embolized with glass beads (60 to 160 μ) in order to establish pulmonary hypertension (pulmonary artery pressure [PAP] doubled from baseline). Prostaglandin E1(PGE1), isoproterenol, prostacyclin (PGI2), and nifedipine were compared at doses producing equivalent reduction in systemic BP.ResultsOnly PGE1and PGI2decreased both PAP and pulmonary vascular resistance (PVR). PGE1decreased PAP from 39 ± 1 to 33 ± 1 mm Hg; prostacyclin decreased PAP from 38 ± 1 to 31 ± 1 mm Hg and produced the largest increase in cardiac output (Qt). Isoproterenol did not change PAP, markedly increased heart rate (162 ± 8 to 216 ± 11 beats/min), and resulted in significant arrhythmias. Nifedipine increased PVR from 1044 ± 113 to 1125 ± 100 dynesec·cm-5and decreased Qt.ConclusionVasodilators demonstrate unique hemodynamic drug profiles. Isoproterenol infusion is characterized by tachycardia and arrhythmias. Both PGE1and PGI2effectively decrease PAP and PVR. Nifedipine depressed Qt significantly in this glass-bead embolization model of acute pulmonary hypertension. (Crit Care 1991; 19:60)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectiveTo study the effects of milrinone on pulmonary vasculature.BackgroundIt has been suggested that bipyridines or their derivatives may have a selective pulmonary vasodilation effect.MethodsPreliminary study: milrinone administration to 12 normal dogs (low dose [bolus 75 μg/kg for 5 min followed by a continuous infusion at 0.75 μg/kg·min, n = 6]; high dose [bolus 150 μg/kg for 5 min followed by continuous infusion at 1.5 μg/kg·min, n = 6]). Main study: milrinone administration to 18 dogs with pulmonary hypertension due to pulmonary embolism induced by a massive injection of autologous muscle cubes. The pulmonary hypertension dogs were divided into three groups: a) group E (n = 6) received embolization only, as control; b) group L (n = 6) received low-dose milrinone; and c) group H (n = 6) received high-dose milrinone, equivalent to the preliminary study group. Hemodynamic measurements and blood samplings were obtained at baseline and at 15, 30, and 60 min after start of milrinone infusion.ResultsMilrinone did not change mean pulmonary artery pressure (MPAP) in normal dogs. Milrinone decreased MPAP significantly in dogs with pulmonary hypertension. Pulmonary vascular resistance index remained at an almost constant level in normal dogs, but decreased significantly in dogs with pulmonary hypertension. Mean arterial pressure was maintained at a constant level in all groups. High-dose milrinone administration decreased systemic vascular resistance index (SVRI) significantly; low-dose milrinone administration decreased SVRI slightly.ConclusionMilrinone may have a selective pulmonary vasodilatory effect only in dogs with pulmonary hypertension. The mechanism that produced a selectivity on pulmonary vasculature in dogs with pulmonary hypertension is unknown. However, an inhibition of platelet aggregation may decrease the MPAP resulting from an increase in cAMP caused by milrinone. Further studies are needed to resolve the pulmonary vasodilatory effect of milrinone in dogs with pulmonary hypertension. (Crit Care Med 1991; 19:68)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Background and MethodsWe demonstrated earlier in our laboratories that fructose-1, 6-bisphosphate (FDP) would improve the outcome of hypoxic ischemic injury to the brain in the adult rabbit. Since many human newborns suffer hypoxic injury to the brain, with a secondary ischemic component due to hypoxic cardiac failure, we set out to reproduce similar experiments in newborn piglets. Hypoxic ischemic CNS damage was induced by ligating both carotid arteries and reducing BP to 66% of normal for 30 min; in the last 15 min, FIO2was reduced to 0.6. Twelve piglets were randomized to receive either 175 mg/kg of FDP in the last 5 min before reoxygenation or the equivalent volume of saline. The other 20 piglets received 75 mg/kg of FDP in the 5 min immediately before carotid ligation, followed by 1.8 mg/kg·min continuous infusion for the 30 min of hypoxia and ischemia or an equivalent volume of saline.ResultsThere were no significant differences in the neurologic exam scores or pathologic exam scores between the FDP and control animals at either dose level.ConclusionIn this animal model, FDP at the doses given was not effective in ameliorating hypoxic ischemic injury to the CNS. (Crit Care Med 1990; 19:75)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectiveTo compare a simplified method of measuring extravascular lung water (EVLW) using only a single indicator (EVLW-SI) with the standard double indicator dilution technique (EVLW-DI).DesignDirect comparison of EVLW-SI with EVLW-DI in 18 critically ill patients.SettingA general medical ICU in a university-affiliated hospital.PatientsNine men and nine women, ages 19 to 80 yr. Six patients were in shock (four from septic shock), and 11 were in respiratory failure.InterventionsEVLW-DI and cardiac output were measured in triplicate during injection of cold indocyanine green dye. Cardiac output was calculated both from pulmonary artery (COPa) and femoral artery (COfem-di) thermal dilution signals. EVLW-SI and COfem-si were also measured during three additional injections of cold saline using only thermal signals from the pulmonary and femoral arteries. Order of measurements was random. EVLW-SI was measured in ten patients while blood was withdrawn through the femoral catheter and in ten patients without blood drawn through the femoral catheter.Measurements and Main ResultsA total of 84 comparisons were made. Although the overall correlations were good (r2= .86), EVLW-SI systematically overestimated EVLW-DI (p< .05). This difference was greater when EVLW-SI was measured without blood withdrawal through the femoral catheter. In this subgroup, mean values for EVLW by the two methods were within 20% of one another in only two of ten patients, in contrast to the results in six of eight patients in which blood was withdrawn through the catheter. COfemsi and COfem-di also overestimated COpa.ConclusionTheoretically, neither injection of green dye nor blood withdrawal should be necessary during measurements of EVLW-SI, making it a simpler technique for bedside use than EVLW-DI. However, significant discrepancies exist between the two techniques. Some of this difference is apparently due to technical factors related to catheter design. In any case, we cannot recommend use of the single indicator dilution technique at present to estimate EVLW. (Crit Care Med 1991; 19:84)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectiveTo present an algorithm for noninvasive measurement of cerebral oxygen saturation (cerebral oximetry) and cerebral hemodynamics with near infrared spectroscopy.DesignIn vitro correlation of oximetry measurements with reference measurements; illustrative cases of hemodynamic and oximetric recordings.SettingTertiary care neuroscience ICU.PatientsBrain-injured patients with a prolonged, decreased level of consciousness chosen as illustrative examples.InterventionsTwo-channel multiple wavelength diffuse infrared transmission spectroscopy was interfaced with the scalp using adhesive. Transmission data were collected with gross superficial-to-deep spatial resolution. Saturation calculation based on the deep signal was observed longitudinally in the patient. With the same technology, arterial input and cerebral response functions, generated by iv tracer bolus, were deconvoluted to measure mean cerebral transit time.Measurements and Main ResultsA positive linear regression fit between diffuse transmission oximetry and measured blood oxygen saturation over the range 23% to 99% (r2= .98,p< .001) was noted.ConclusionThe approach used overcomes previously identified difficulties with cerebral oximetry, and demonstrates excellent in vitro correlation. The technique can be performed clinically without difficulty. A simultaneous measure of mean cortical transit time is possible. (Crit Care Med 1991; 19:89)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

ObjectiveTo compare the relationship between variability in nitroprusside delivery from five infusion pumps and the resulting variability in mean arterial pressure (MAP).DesignRandomized, crossover study design.SettingA pediatric ICU in a university hospital.PatientsInformed parental consent was obtained for six patients who were hemodynamically stable and receiving a continuous nitroprusside infusion for a clinical application. Subjects ranged in age from 11 months to 9 yr.InterventionsAll of the subjects were administered nitroprusside using selected infusion pumps, which included Abbott (Micro), 3M/AVI (210), IMED (965), IVAC (565), and Kendall McGraw (MicroRate).Measurements and Main ResultsAfter an initial equilibration interval for each device, MAP was measured and recorded at 10-sec intervals for ≥90-min intervals using a computerized data collection technique. Variation in nitroprusside administration (flow continuity) for each infusion pump was determined in vitro using a computerized gravimetric technique. Variation in both MAP and flow continuity was mathematically expressed as the coefficient of variance (CV) of the measured values for each of the respective infusion pumps. For the Abbott, IMED, 3M/AVI, IVAC, and Kendall McGaw infusion pumps, mean ± SD continuity CV values were 85 ± 31%, 39 ± 26%, 19 ± 8%, 17 ± 3%, and 12 ± 3%, respectively, and MAP CV values were 18 ± 21%, 15 ± 11%, 8 ± 2%, and 16 ± 10%, respectively.ConclusionAn apparent direct relationship between MAP variability and flow continuity was observed. We speculate that variation in effect of potent short-acting drugs may, in part, be due to infusion pump operation. (Crit Care Med 1991; 19:98)

ISSN:0090-3493    

出版商:OVID    

年代:1991

数据来源: OVID