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Biomedical subjects

B Krafte-Jacobs

Publications and source records attributed to B Krafte-Jacobs.

18 recordsLinked to original sources
PubMed1998

Effect of non-pulsatile renal blood flow on plasma erythropoietin.

Erythropoietin is a hormone responsible for regulation of red blood cell production. Circulating erythropoietin values are regulated by renal oxygen supply, which is determined by hemoglobin concentration, hemoglobin oxygen saturation, and renal blood flow. Previous animal and human studies regarding erythropoietin regulation have assumed pulsatile renal blood flow. During cardiopulmonary bypass, non-pulsatile renal perfusion has been shown to result in decreased glomerular filtration rate and decreased renal blood flow in comparison to pulsatile perfusion. Repair of congenital heart disease during cardiopulmonary bypass is an attractive circumstance in which to study the effect of non-pulsatile blood flow on erythropoietin production. The hypothesis in this study was that non-pulsatile perfusion would result in increased erythropoietin production because of decreased renal oxygen supply. Fourteen children with congenital heart disease and without preoperative renal insufficiency or anemia were enrolled in the study. All patients underwent cardiopulmonary bypass with non-pulsatile flow. In addition, 10 control patients without congenital heart disease were enrolled. Six cardiopulmonary bypass patients had 1.5- to 6-fold increases in plasma erythropoietin concentrations from baseline. These patients had longer cardiopulmonary bypass times, more commonly performed under low flow deep hypothermic conditions. The remaining 8 patients with congenital heart disease, and all control patients, did not develop increased postoperative erythropoietin concentrations. The conditions under which cardiopulmonary bypass are performed appear to influence postoperative circulating erythropoietin concentrations.

Cardiopulmonary Bypass↗
PubMed1998

Increased circulating thrombomodulin in children with septic shock.

OBJECTIVES: To test the hypothesis that children diagnosed with septic shock have increased plasma thrombomodulin values as a manifestation of microcirculatory dysfunction and endothelial injury; to determine whether plasma thrombomodulin concentrations are associated with the extent of multiple organ system failure and mortality. DESIGN: Prospective, cohort study. SETTING: Pediatric intensive care unit. PATIENTS: Twenty-two children with septic shock and ten, healthy, control children. INTERVENTIONS: Blood samples were obtained for plasma thrombomodulin determinations every 6 hrs for 72 hrs in septic shock patients and once in healthy control patients. MEASUREMENTS AND MAIN RESULTS: Thirty-two children (22 septic shock, and 10 healthy controls) were enrolled in the study. Thrombomodulin concentrations were determined by an enzyme-linked immunosorbent assay. Septic shock nonsurvivors had significantly greater mean thrombomodulin concentrations (10.6 +/- 2.2 ng/mL) than septic shock survivors (5.5 +/- 0.6 ng/mL) (p < .05) and healthy control patients (3.4 +/- 0.2 ng/mL) (p < .01). Mean thrombomodulin values increased as the number of organ system failures increased. CONCLUSIONS: Pediatric survivors and nonsurvivors of septic shock have circulating thrombomodulin concentrations 1.5 and 3 times greater than healthy control patients. These findings likely represent sepsis-induced endothelial injury. Patients with multiple organ system failure have circulating thrombomodulin concentrations which are associated with the extent of organ dysfunction. We speculate that measurement of plasma thrombomodulin concentrations in septic shock may be a useful indicator of the severity of endothelial damage and the development of multiple organ system failure.

Adolescent↗
PubMed1998

Aerosolization of novel nitric oxide donors selectively reduce pulmonary hypertension.

OBJECTIVES: Inhaled 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. DESIGN: Prospective, randomized, controlled study. SETTING: Research laboratory. SUBJECTS: Yorkshire pigs (n = 18), weighing 11.4 to 16.4 kg. INTERVENTIONS: In 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 RESULTS: Mean 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). CONCLUSIONS: In 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.

Acute Disease↗
PubMed1997

Circulating methemoglobin and nitrite/nitrate concentrations as indicators of nitric oxide overproduction in critically ill children with septic shock.

OBJECTIVES: To examine the relationship between circulating methemoglobin and nitrite/nitrate concentrations and to compare these markers of nitric oxide overproduction with clinical variables in children diagnosed with septic shock. DESIGN: Prospective, controlled, clinical study. SETTING: Pediatric intensive care unit and outpatient clinic in a children's hospital. PATIENTS: Twenty-two children diagnosed with septic shock and ten age-matched healthy control patients. INTERVENTIONS: Patients diagnosed with septic shock had blood specimens taken on study entry and every 6 hrs for 72 hrs for methemoglobin and nitrite/nitrate determinations. Single blood specimens were obtained from controls. MEASUREMENTS AND MAIN RESULTS: Circulating methemoglobin and nitrite/nitrate concentrations were significantly higher in children diagnosed with septic shock in comparison with healthy control children (p = .01 and .05, respectively). Peak nitrite/nitrate concentrations correlated with serum creatinine (r2 = .19; p = .04) and were inversely correlated with arterial pH (r2 = .28; p = .01) and urine output (r2 = .21; p = .03) when analyzed by log-linear regression. There were no significant relationships between methemoglobin and nitrite/nitrate or between methemoglobin and any other clinical variable. CONCLUSIONS: Circulating methemoglobin and nitrite/nitrate concentrations are increased in children diagnosed with septic shock. Plasma nitrite/nitrate values correlate with selected clinical variables in these children. Circulating methemoglobin measurements are not superior to plasma nitrite/nitrate concentrations as an indicator of endogenous overproduction of nitric oxide in children diagnosed with septic shock. A need remains to develop markers of endogenous nitric oxide activity that have greater accuracy and reliability.

Adolescent↗
PubMed1997

Intratracheal instillation of a novel NO/nucleophile adduct selectively reduces pulmonary hypertension.

We examined the pulmonary and systemic hemodynamic effects of administering soluble nitric oxide (NO) donor compounds (NO/nucleophile adducts, i.e., NONOates) directly into the trachea of animals with experimentally induced pulmonary hypertension. Steady-state pulmonary hypertension was created by using the thromboxane agonist U-46619. Yorkshire pigs were randomly assigned to one of four groups: group 1, intratracheal saline (control; n = 8); group 2, intratracheal sodium nitroprusside (n = 6); group 3, intratracheal ethylputreanine NONOate (n = 6); and group 4, intratracheal 2-(dimethylamino)-ethylputreanine NONOate (DMAEP/NO; n = 6). Pulmonary and systemic hemodynamics were monitored after drug instillation. Group 4 had significant reductions in pulmonary vascular resistance index (PVRI) at all time points compared with steady state and compared with group 1 (P < 0.05), whereas systemic vascular resistance index did not change. The mean change in mean pulmonary arterial pressure in group 4 was -33.1 +/- 1.2% compared with +6.4 +/- 1.3% in group 1 (P < 0.001), and the mean change in mean arterial pressure was -9.3 +/- 0.7% compared with a control value of -0.9 +/- 0.5% (P < 0.05). Groups 2 and 3 had significant decreases in both PVRI and systemic vascular resistance index compared with steady state and with group 1. In conclusion, intratracheal instillation of a polar-charged tertiary amine NONOate DMAEP/NO results in the selective reduction of PVRI. Intermittent intratracheal instillation of selective NONOates may be an alternative to continuously inhaled NO in the treatment of pulmonary hypertension.

Amino Acids, Diamino↗
PubMed1996

Circulating erythropoietin and interleukin-6 concentrations increase in critically ill children with sepsis and septic shock.

OBJECTIVES: To investigate a possible relationship between plasma erythropoietin and interleukin-6 (IL-6) in critically ill children with sepsis or septic shock. To examine the modulatory effects of plasma from these patients on erythropoietin production in vitro, employing a cell culture system that uses the erythropoietin-producing Hep 3B cell line. DESIGN: A prospective, controlled clinical and laboratory study. SETTING: A pediatric intensive care unit and research laboratory facility at a children's hospital. PATIENTS: Children admitted to the pediatric intensive care unit with the diagnosis of sepsis or septic shock (n = 16), and control patients without infection or anemia (n = 16) were admitted to the study. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Blood samples were obtained from 16 children with sepsis or septic shock, and 16 age-matched controls. Plasma erythropoletin and IL-6 concentrations were measured using an enzyme-linked immunoassay. Plasma erythropoietin concentrations were significantly higher in children with sepsis or septic shock (120 +/- 26 mlU/mL) than in controls (10 +/- 2 mlU/mL) (p < .001). Plasma IL-6 concentrations were greater in children diagnosed with sepsis or septic shock (12,405 +/- 6662 pg/mL) than in control patients (7 +/- 1 pg/mL) (p < .001), and higher in septic shock patients (27,469 +/- 13,647 pg/mL) than sepsis patients (688 +/- 258 pg/mL) (p = .03). Hep 3B cells were incubated under hypoxic conditions in media containing plasma from control patients, or patients diagnosed with sepsis or septic shock. Media concentrations of erythropoietin were measured using an enzymelinked immunoassay. Hep 3B cells incubated with plasma from patients diagnosed with sepsis or septic shock produced more erythropoietin (216 +/- 23 mlU/mL) than Hep 3B cells incubated under the same conditions in media containing plasma from control patients (152 +/- 11 mlU/mL) (p = .04). Hypoxic Hep 3B cell erythropoietin production in media incubated with plasma from patients diagnosed with sepsis or septic shock correlated significantly (although weakly) with plasma IL-6 values from these same patients (p = .03, r2 = .28). CONCLUSIONS: Plasma erythropoietin and IL-6 values are increased in critically ill children with sepsis or septic shock in comparison with controls. The data indicate that one or more plasma factors are responsible for stimulation of hypoxia-induced erythropoietin production in the Hep 3B cell line and suggest a possible role for IL-6 in the regulation of erythropoletin production in critically ill children with sepsis or septic shock.

Adolescent↗
PubMed1996

Rapid placement of transpyloric feeding tubes: a comparison of pH-assisted and standard insertion techniques in children.

OBJECTIVE: To compare transpyloric feeding tube placement using a pH-assisted placement technique versus a standard placement technique in pediatric patients requiring enteral nutrition. METHODS: Critically ill children younger than 4 years were prospectively and randomly assigned to either a pH-assisted or a standard feeding tube placement group. Identical pH-assisted feeding tubes were used in both groups; however, feeding tubes in the standard group were not attached to a portable pH meter. Successful transpyloric placement was confirmed by radiography before beginning feedings. If placement was not successful, a second placement attempt was made after metoclopramide administration. Information regarding tube placement success, number of radiographs, time to initiation of feedings, and daily caloric intake was collected. A cost comparison between the two groups was performed. RESULTS: Thirty-four patients were enrolled in the pH-assisted group, and 34 were enrolled in the standard feeding tube group. Ninety-seven percent of patients in the pH-assisted group had successful placement after the first attempt, compared with 53% of patients in the standard group. The average time to successful placement of pH-assisted feeding tubes was 6 minutes. All patients in the pH-assisted group had successful placement after the second attempt, compared with 78% of patients in the standard group. A pH of greater than 5.6 accurately predicted transpyloric placement in 97% (33 of 34) of individuals in the pH-assisted group. Children in the pH-assisted group required significantly fewer radiographs than those in the standard group. Hospital costs were $114 per patient in the pH-assisted group and $135 per patient in the standard group. CONCLUSIONS: Our findings indicate that bedside transpyloric placement of pH-assisted feeding tubes can be accomplished rapidly and with a high success rate. This method is associated with decreased radiation exposure and economic savings when compared with a standard placement technique.

Child, Preschool↗
PubMed1995

Plasma erythropoietin reference ranges in children.

Plasma erythropoietin values were determined in 1122 hospitalized and outpatient children aged 1 to 18 years with a commercially available enzyme-linked immunosorbent assay. A computerized approach based on the Hoffman technique was used to establish erythropoietin reference ranges. Plasma erythropoietin values ranged from 1.0 to 21.9 mIU/ml in male subjects, and from 1.1 to 20.5 mIU/ml in female subjects (2.5th to 97.5th percentiles).

Adolescent↗
PubMed1995

Catheter-related thrombosis in critically ill children: comparison of catheters with and without heparin bonding.

OBJECTIVE: To compare the incidence of and factors associated with vascular thrombosis after placement of heparin-bonded and standard femoral venous catheters. DESIGN: Prospective, masked, clinical study. SETTING: Multidisciplinary, tertiary, pediatric intensive care unit. PATIENTS: Consecutive cases (n = 50) of critically ill children admitted to a pediatric intensive care unit in whom either a heparin-bonded (n = 25) or a standard (n = 25) femoral venous catheter was placed. MEASUREMENTS AND MAIN RESULTS: Patients were examined by ultrasonography within 3 days of catheter insertion, weekly while the catheter was in place, and after catheter removal for evidence of vascular thrombosis. Data were collected prospectively regarding clinical evidence of catheter thrombosis, infusate composition, and positive blood culture results. Of 50 patients, 13 (26%) had thrombotic complications, 11 (44%) of the 25 patients in the standard-catheter group, in comparison with 2 (8%) of the 25 patients in the heparin-bonded catheter group (p = 0.004). In addition, there was a significantly higher incidence of positive blood culture results among patients in the standard-catheter group (24% vs 0%; p = 0.009). Positive catheter blood culture results were obtained in 38% of patients with thrombosis versus 3% without thrombosis (p = 0.001). Clinical evidence of thrombosis was found in 69% of patients with, versus 27% of patients without, ultrasound-proved thrombosis (p = 0.007). CONCLUSION: Heparin bonding of catheters is associated with significantly fewer thrombotic complications. A reduced incidence of positive catheter-related blood culture results may be associated with the absence of thrombosis.

Catheterization, Central Venous↗
PubMed1995

Cat-scratch disease associated with pleural effusions and encephalopathy in a child.

Cat-scratch disease has been associated with a variety of systemic manifestations. We present a case of cat-scratch disease associated with bilateral pleural effusions and encephalopathy in a child. The particular combination of findings reported here may be more ubiquitous than formerly suspected and widen the clinical description of this condition.

Biopsy↗
PubMed1995

Comparison of gastric intramucosal pH and standard perfusional measurements in pediatric septic shock.

OBJECTIVE: To examine the utility of gastric tonometry as an early indicator of morbidity and mortality in pediatric patients with septic shock. DESIGN: Prospective clinical study. SETTING: Multidisciplinary pediatric ICU. PATIENTS: Eight critically ill pediatric patients with septic shock and with pulmonary artery and gastric tonometry catheters in place. INTERVENTIONS: Standard perfusional data including cardiac index, oxygen content (arterial, mixed venous), oxygen delivery, oxygen consumption, urine output, capillary refill, and lactate value were measured every 4 h. Intramucosal pH (pHi) was calculated from simultaneous tonometric measurements of gastric intramucosal PCO2 (PiCO2). Mean pHi values were compared between survivors and nonsurvivors. Tonometric data were compared with standard perfusional data by regression analysis. Low pHi values (< 7.35) were temporally compared with occurrence screens for adverse clinical events, (cardiopulmonary arrest, acute hemorrhage, and significant hypotension or dysrhythmias). MEASUREMENTS AND MAIN RESULTS: Sets (n = 108) of paired data were collected from 8 patients (age 7 to 168 months) representing 4 deaths. The mean pHi in nonsurvivors (7.32 +/- 0.18) was significantly lower than that in survivors (7.48 +/- 0.07). Both pHi and PiCO2 were correlated with urine output by regression analysis. The pHi, but not PiCO2 correlated with extraction ratio and lactate level. There were no other significant correlations noted. Analysis of the ability of pHi values to predict adverse clinical events revealed that pHi less than 7.35 accurately predicted 26 of 39 concurrent or subsequent adverse clinical events. However, 24 of 50 pHi values less than 7.35 showed no association with similar adverse events, either concurrent or subsequent. The pHi had a sensitivity of 67%, a specificity of 74%, a positive predictive value of 52%, and an efficiency of 72% in predicting these adverse events. CONCLUSION: Use of gastric tonometry in pediatric septic shock patients appears to distinguish survivors from nonsurvivors. However, in general, tonometric assessment of splanchnic perfusion correlates poorly with standard clinical, hemodynamic, oxygen transport, or metabolic measurements of perfusion. Low pHi measurements are not predictive of concurrent or subsequent adverse clinical events.

Adolescent↗
PubMed1994

Erythropoietin response to critical illness.

OBJECTIVE: To examine the endogenous erythropoietin response in critically ill children with acute anemia or acute hypoxemia. DESIGN: A prospective case study of critically ill acutely anemic, and acutely hypoxemic pediatric patients compared with control groups of critically ill nonanemic and nonhypoxemic patients and with a hemoglobin and age-matched, chronically anemic patient group. SETTING: Multidisciplinary, tertiary, pediatric intensive care unit (ICU). PATIENTS: Critically ill patients admitted to the pediatric ICU during an 11-month period between February 1992 and March 1993 with acute anemia (n = 21), acute hypoxemia (n = 18), or neither anemia nor hypoxemia (n = 10). Outpatients with chronic anemia (n = 21) and no acute illness were also studied as a comparison group. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Ages were equivalent among the groups and averaged 57.4 +/- 47.2 months (range 1 to 144). Acutely hypoxemic and critically ill control patients had normal hemoglobin levels. Acutely anemic patients had a hemoglobin level equivalent to chronically anemic outpatients, but lower (p < .001) hemoglobin levels than acutely hypoxemic and critically ill control patients. The serum erythropoietin concentrations in the acutely anemic group were significantly lower than erythropoietin values in the chronically anemic group (39.3 +/- 62.2 vs. 861 +/- 758 mU/mL, p < .001) and similar to erythropoietin concentrations in the critically ill control (13.5 +/- 10.5 mU/mL) and acutely hypoxemic (5.2 +/- 3.3 mU/mL) patient groups. Only ten of 49 critically ill patients had an erythropoietin concentration above normal, compared with 20 of 21 chronically anemic patients, whose erythropoietin concentrations were above normal. CONCLUSIONS: The erythropoietin response to known physiologic stimuli is blunted in critically ill children. This blunted erythropoietin response may result in increased transfusion requirements.

Acute Disease↗
PubMed1993

The constipated serviceman: prevalence among deployed U.S. troops.

The prevalence of constipation in deployed servicemen was determined in a sample of military personnel aboard the USS Iwo Jima LPH 2 during Operation Desert Shield. Results were obtained from a bowel function questionnaire issued to 500 deployed marines and sailors. When constipation is defined as no bowel movement for greater than 3 days, 3.9% of the Marine/sailor personnel are constipated when in their home environment as compared to 6.0% when they are aboard ship and 30.2% while in the field. Alternatively, when constipation is defined as the presence of certain anorectal complaints (hard stools, straining, painful defecation, and bleeding with defecation), the incidence is 7.2% when at home as compared to 10.4% aboard ship and 34.1% in the field. These results confirm that whether constipation is defined as infrequent bowel movements or presence of symptoms of constipation, significantly more servicemen will be constipated when in the field as compared to their home environment. Since approximately one-third of Navy/Marine Corps personnel deployed in a field environment will be constipated, preventive measures ought to be evaluated.

Adolescent↗
PubMed1992

A method for shipboard treatment of multiple heat casualties.

A method is presented for the treatment aboard ship of multiple patients afflicted with life-threatening heat illness, using an inflatable life raft cooling system. The potential benefits of this method include: (1) the utilization of readily available materials aboard U.S. Naval vessels; (2) the provision for rapid patient cooling by evaporation while maintaining patient safety and comfort; (3) the ability to treat many patients simultaneously with minimal attendant personnel; and (4) the maintenance of patient access allowing for monitoring and the administration of additional supportive measures.

Emergencies↗