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Biomedical subjects

J B Hall

Publications and source records attributed to J B Hall.

At least 37 records · Page 2Linked to original sources
PubMed1999

Response to inhaled nitric oxide in patients with acute right heart syndrome.

Inhaled nitric oxide (iNO), a selective pulmonary vasodilator, has been shown to decrease pulmonary artery pressures but not increase cardiac output in hemodynamically stable patients with a variety of causes of pulmonary hypertension. The response to iNO in hemodynamically unstable patients with acute right heart syndrome has not been previously described. We determined the response to iNO in 26 critically ill adult patients with acute right heart failure defined by echocardiographic criteria. Patients received iNO through the inspiratory limb of the ventilator in increments of 10 ppm with hemodynamic and gas-exchange measurements made before and after each level. When maximal effect was seen, iNO was discontinued to compare parameters with baseline. iNO significantly increased cardiac output (5.5 +/- 3 to 6.4 +/- 4 L/min), stroke volume (54 +/- 27 to 65 +/- 38 ml), and mixed-venous oxygen saturation (69 +/- 8 to 73 +/- 10%), all p < 0.01. With discontinuation of iNO, all parameters returned immediately to baseline. These parameters of improved perfusion were related to a decrease in pulmonary vascular pressures and resistance. In a subset of approximately 50% of patients, these changes were substantial (> 20%) and in approximately 25% of all patients, the improvement in hemodynamic measures permitted a decrease in other vasoactive drug administration. The mean concentration of iNO required to achieve these effects was 35 ppm, and 85% of patients exhibiting a substantial improvement in hemodynamics did so at a concentration of iNO of less than or equal to 40 ppm. Underlying causes of right heart failure and baseline hemodynamics did not predict response to iNO, but the use of alpha-agonist catecholamines did. We conclude iNO improves hemodynamics in patients with respiratory failure, shock, and right ventricular dysfunction. Although mortality was not a key end point in this pilot study, it was high for both responders and nonresponders to this therapy. Further evaluation of the role of iNO in this patient population is supported by these data.

Acute Disease↗
PubMed1999

The impact of morbid obesity on oxygen cost of breathing (VO(2RESP)) at rest.

Oxygen consumption dedicated to respiratory work (V O(2RESP)) during quiet breathing is small in normal patients. In the morbidly obese, at high minute ventilations, VO(2RESP) is greater than in normal patients, but VO(2RESP) during quiet breathing in these patients is not known. We postulated that such patients have increased VO(2RESP) at rest which may predispose them to respiratory failure when additional respiratory workloads are imposed. We measured baseline VO(2) in morbidly obese patients immediately prior to gastric bypass surgery and again after intubation, mechanical ventilation, and paralysis, and compared their change in VO(2) to nonobese patients scheduled for elective abdominal surgery. Baseline VO(2) was higher in the obese patients compared with control patients (354.6 versus 221.4 ml/min; p = 0.0001) and the change in VO(2) from spontaneous breathing to mechanical ventilation was significant in the obese patients (354.6 versus 297.2 ml/min; p = 0.0002) but not the control patients (221.4 versus 219.8 ml/min; p = 0.86). We conclude that morbidly obese patients dedicate a disproportionately high percentage of total VO(2) to conduct respiratory work, even during quiet breathing. This relative inefficiency suggests a decreased ventilatory reserve and a predisposition to respiratory failure in the setting of even mild pulmonary or systemic insults.

Adult↗
PubMed1999

Outcomes of critically ill cancer patients in a university hospital setting.

Critically ill cancer patients constitute a large percentage of admissions to tertiary care medical intensive care units (ICUs). We sought to describe outcomes of such patients, and to evaluate how conditions commonly seen in these patients impact mortality. A total of 348 consecutive medical ICU cancer patients were evaluated. Subgroup comparisons included the three most common cancer types (leukemia, lymphoma, lung cancer), as well as three different treatments/conditions (bone marrow transplant [BMT] versus non-BMT, mechanical ventilation [MV] versus non-MV, neutropenic versus non-neutropenic). There were no mortality differences between patients with leukemia, lymphoma, or lung cancer. By logistic regression, mortality predictors were: MV, hepatic failure, and cardiovascular failure for the group as a whole (41% overall mortality); MV and allogeneic (as compared with autologous) BMT for the BMT group (39% overall mortality); hepatic failure, cardiovascular failure, and persistent acute respiratory distress syndrome (ARDS) for the MV group (67% overall mortality); and MV for the neutropenic group (53% overall mortality). Neutropenia showed no independent association with mortality in the group as a whole or any subgroup analyzed. We conclude that respiratory, hepatic, and cardiovascular failure predict mortality, whereas neutropenia does not. Additionally, we have noted an encouraging improvement in survival in many groups of critically ill cancer patients.

APACHE↗
PubMed1999

The incidence of and clinical variables associated with vancomycin-resistant enterococcal colonization in mechanically ventilated patients.

STUDY OBJECTIVES: (1) To determine in our ICU the incidence of vancomycin-resistant enterococcus (VRE) colonization in mechanically ventilated patients without a history of VRE infection or colonization; and (2) to determine the risk factors and outcome variables associated with VRE colonization in these patients. DESIGN: A prospective cohort study conducted between January 1996 and March 1998. SETTING: Medical and cardiac critical care units in a tertiary care urban university hospital. PATIENTS: Mechanically ventilated patients without evidence of pneumonia at the onset of ventilation. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Patients underwent rectal cultures by standard methods on day 1, day 3 or 4, day 6 or 7, and day 14 of intubation to detect VRE. Thirteen of 83 patients (16%) had rectal cultures positive for VRE (VRE+) at some point while being mechanically ventilated during their stay in the ICU. In comparison, approximately 15 of 2,100 medical ICU patients (0.7%) had clinical VRE infections as determined by the hospital's infection control program during a 2-year period. VRE+ patients had a higher incidence of immunosuppression than patients who had rectal cultures negative for VRE (VRE-) (9 of 13 [69%] vs 16 of 70 [23%], respectively; p < 0.01) and neutropenia (4 of 13 [31%] vs 5 of 70 [7%], respectively; p < 0.01). Hospital length of stay (LOS) was longer in VRE+ patients than in VRE- patients (27+/-17 days vs 17+/-14 days, respectively; p = 0.05), whereas pre-ICU hospital LOS and ICU LOS were similar in both patient groups. Five of 67 patients (7%) were VRE+ on day 1 of intubation, suggesting colonization at a prior site of care. Three of 29 patients who had subsequent rectal cultures converted to VRE+ while in the ICU. This group had a higher incidence of immunosuppression and neutropenia, and received more vancomycin compared with the patients who remained VRE- (p < 0.01). However, there was no significant difference in the use of other broad-spectrum antibiotics (such as antipseudomonal penicillins, third-generation cephalosporins, quinolones, and clindamycin), enteral tube feedings, or sucralfate between the two groups. In addition, a topical antibiotic paste (a gentamicin, nystatin, polymixin slurry) that was placed in the oropharynx to prevent bacterial overgrowth was not found to increase the incidence of VRE colonization in this patient population. CONCLUSIONS: The incidence of VRE colonization was surprisingly high: 16% in mechanically ventilated patients in a hospital in which VRE was not previously known to be endemic. Risk factors for the acquisition of VRE colonization included immunosuppression, neutropenia, and vancomycin use. Increased LOSs and hospital costs were seen in VRE+ patients compared to VRE- patients. Whether VRE colonization is a contributor to severe disease that leads to prolonged hospitalization and increased resource allocation or whether it is simply a marker of disease severity cannot be determined from this study. To the extent that specific antibiotic protocols are used to reduce antibiotic-resistant flora in the ICU, monitoring the incidence of VRE in the stool specimens of immunocompromised, mechanically ventilated patients can be a simple and useful tool to assess one effect of these strategies.

Anti-Bacterial Agents↗
PubMed1999

Determination of hemoglobin saturation in patients with acute sickle chest syndrome: a comparison of arterial blood gases and pulse oximetry.

STUDY OBJECTIVES: To evaluate three different methods of measuring oxygen saturation in patients suffering from acute sickle chest syndrome. DESIGN: A prospective, descriptive study of 9 months' duration. SETTING: A tertiary care university hospital. PATIENTS: Adult patients with acute sickle chest syndrome scheduled to undergo RBC exchange transfusion. INTERVENTIONS: None. MEASUREMENTS: Baseline hemoglobin oxygen saturation was determined simultaneously by (1) calculation based on PaO2 and an oxyhemoglobin dissociation curve algorithm, (2) co-oximetry, and (3) pulse oximetry. These same measures were repeated after exchange transfusion. Baseline and postexchange hemoglobin electrophoresis was performed in all patients. RESULTS: Baseline calculated saturation overestimated true saturation (determined by co-oximetry) with a baseline mean bias (co-oximetry minus calculated saturation) of -6.78 +/- 2.63% (95% confidence interval for bias: -8.37% to -5.19%). Pulse oximetry was not different than co-oximetry at baseline with a baseline bias of +1.86 +/- 3.25% (95% confidence interval: -0.1% to 3.82%). After exchange transfusion, there was no bias between either co-oximetry and calculated saturation (mean difference: -0.17 +/- 1.31% [95% confidence interval: -0.95% to 0.61%]), or co-oximetry and pulse oximetry (mean difference: +0.3 +/- 1.53% [95% confidence interval: -0.62% to 1.22%]). CONCLUSIONS: Calculated saturation overestimates true saturation during acute sickle chest syndrome. This discrepancy abates after exchange transfusion. Pulse oximetry more closely follows co-oximetry than does calculated saturation during acute sickle chest syndrome.

Acute Disease↗
PubMed1999

Cyclophosphamide in the treatment of pulmonary diseases: survey of use, training, and practitioner knowledge base.

OBJECTIVE: To assess pulmonologists' use, training in the use, and knowledge base of the drug cyclophosphamide. DESIGN: Survey through questionnaire. Testing of knowledge base before and after instructional conference. PARTICIPANTS AND METHODS: Pulmonologists (94 attendings, 31 fellows), selected randomly at the 1996 and 1997 annual meetings of The American Thoracic Society, completed surveys of their use and training in the use of cyclophosphamide. Thirty-five attending at the 1998 meeting completed a test of knowledge base of the drug. Members of the pulmonary teaching service at The University of Chicago Hospitals completed the test before and after a case-based conference designed to educate pulmonologists in the use of the drug. RESULTS: Forty-three percent of the attending pulmonologists and 55% of the fellows were currently using the drug in the management of their patients; 77% of the attending pulmonologists had prescribed the drug in the past. Nonmalignant diseases for which the drug was prescribed included usual interstitial pneumonitis/desquamative interstitial pneumonitis, vasculitis, collagen vascular disease, constrictive bronchiolitis, sarcoid, and Goodpasture's disease. Sixty-eight percent of attending pulmonologists and 81% of fellows had no training in the drug's use. Of the attending pulmonologists who made use of the drug, 64% were prescribing and managing its use themselves. Of those who prescribed and managed the drug's use themselves, 65% had had no training in its use. Of those fellows who prescribed and managed the drug's use themselves, 73% had had no training in the drug's use. On knowledge-based testing, the average correct score was 30 +/- 10%. With an educational conference, average pre- and post-test scores rose from 40 +/- 10% to 80 +/- 10% (p < 0.001). CONCLUSION: Cyclophosphamide had been used by the vast majority of pulmonologists, either currently or in the past, for a wide variety of lung diseases. Its use is commonly managed by physicians who have no specific training relevant to this agent. Practitioner knowledge base of the drug is poor, and case-based conferences in fellowship may be an effective means of imparting information concerning this drug.

Congresses as Topic↗
PubMed1998

Liberation from mechanical ventilation: a decade of progress.

Multiple complications associated with mechanical ventilation mandate that clinicians expeditiously define and reverse the pathophysiologic processes that precipitate respiratory failure and then, detect the earliest point that a patient can breathe without the ventilator. Over the past decade, numerous laboratory and clinical studies have been reported that may inform transformation of the "art of weaning" to the science of liberation. We review these studies and use them to formulate a systematic approach to assure early, safe, and successful liberation of patients from mechanical ventilation.

Algorithms↗
PubMed1998

Effect of nutritional management, trace mineral supplementation, and norgestomet implant on attainment of puberty in beef heifers.

We conducted a study to evaluate the influences of nutritional management, trace mineral supplementation, and exogenous progesterone on attainment of puberty in beef heifers. Heifers (n = 180) were assigned at weaning to blocks and treatments. Treatments included two dietary regimens (corn silage vs pasture + oatlage), trace mineral supplementation, and puberty induction strategy (with or without progestin implant). Heifers that received pasture + oatlage were managed on grass-legume pastures from October 14 until December 14 and were then placed in pens and fed an oatlage-based diet through May 1994. Heifers fed the corn silage-based diet were housed in pens throughout the study. Norgestomet was implanted in half of the heifers on April 11 for 10 d. Progestin implant increased (P < .05) the number of heifers that had attained puberty by the end of the study, compared with nonimplanted heifers (89% vs 71%). Trace mineral supplementation did not affect percentage of heifers that reached puberty before the implant period. Plasma copper levels were below recommended levels in heifers fed oatlage-based diets without trace minerals. We conclude that heifers can be placed on regrowth in irrigated pastures during the fall and still make acceptable gains for attainment of puberty the following spring and that progestin treatment can aid in inducing heifers to reach puberty.

Animal Nutritional Physiological Phenomena↗
PubMed1997

Radiation myelopathy after chemotherapy and radiation therapy for fallopian tube carcinoma.

Radiation myelopathy is a severe consequence of radiation to the spinal cord which rarely occurs with standard doses of radiation. This entity commonly results in different degrees of sensory and motor deficits. Diagnosis of radiation myelopathy in women with gynecologic malignancies may increase with the concomitant use of chemotherapy and radiation therapy. This paper reports the effect of this combination therapy in a 60-year-old woman with fallopian tube carcinoma.

Fallopian Tube Neoplasms↗
PubMed1997

Primary care by obstetricians and gynecologists: attitudes of the members of The South Atlantic Association of Obstetricians and Gynecologists.

OBJECTIVE: Our purpose was to determine the extent of primary care delivered by obstetrician-gynecologists and compare practice patterns with published primary care and preventive service guidelines. STUDY DESIGN: All 277 active fellows of The South Atlantic Association of Obstetricians and Gynecologists were mailed a self-administered questionnaire. The type of primary care offered by these physicians and their attitudes about the training of residents in obstetrics and gynecology were surveyed. Physicians were categorized as generalists or specialists on the basis of the completion of a fellowship program. Descriptive statistics and chi 2 analysis were used for statistical analysis. RESULTS: Completed surveys were returned by 82% of the fellows. The majority of the respondents perceived their practice as specialty care for women. Generalists offered recommended screening services to women of all ages with greater frequency than the specialists did (p = 0.05). Both groups did not provide care for the chronic medical illnesses most commonly seen in a primary care practice. The respondents favored more residency training in those common acute illnesses frequently encountered in a primary care setting. CONCLUSIONS: Obstetrician-gynecologists in The South Atlantic Association of Obstetricians and Gynecologists selectively practice primary care. These physicians did not support caring for chronic medical problems frequently treated in an ambulatory care practice.

Attitude of Health Personnel↗
PubMed1997

Inhaled helium-oxygen revisited: effect of inhaled helium-oxygen during the treatment of status asthmaticus in children.

OBJECTIVES: To assess the effects of breathing a low-density gas mixture on dyspnea and the pulsus paradoxus in children with status asthmaticus. DESIGN: In an urban academic tertiary referral center, 18 patients, aged 16 months to 16 years, who were being treated for status asthmaticus with continuously inhaled beta-agonist and intravenously administered methylprednisolone and had a pulsus paradoxus of greater than 15 mm Hg received either an 80%:20% helium-oxygen gas mixture (HELIOX patients) or room air (control patients) at 10 L/min by nonrebreathing face mask in a double-blind, randomized, controlled trial. In all patients, baseline data, including pulsus paradoxus (determined by sphygmomanometer or arterial catheter blood pressure readings), respiratory rate, heart rate, investigator-scored dyspnea index, and oxygen saturation, were compared with values obtained 15 minutes during and after intervention. In a subset of patients, peak flows before and after breathing HELIOX or room air were measured. When clinically indicated, arterial blood gases were obtained. RESULTS: The pulsus paradoxus (in millimeters of mercury) fell significantly from an initial mean value of 23.3 +/- 6.8 to 10.6 +/- 2.8 with HELIOX breathing (p < 0.001) and increased again to 18.5 +/- 7.3 after cessation of HELIOX. Peak flow increased 69.4% +/- 12.8% during HELIOX breathing (p < 0.05). The dyspnea index decreased from an initial mean value of 5.7 +/- 1.3 to 1.9 +/- 1.7 with HELIOX breathing (p < 0.0002) and increased again to 4.0 +/- 0.5 after cessation of HELIOX breathing. In control patients, there was no significant difference in pulsus paradoxus or dyspnea index at any time during the study period. Mechanical ventilation was averted in three patients in whom dyspnea lessened dramatically during breathing of HELIOX. CONCLUSION: During acute status asthmaticus, inhaled HELIOX significantly lowered the pulsus paradoxus, increased peak flow, and lessened the dyspnea index. Moreover, HELIOX spared three patients a planned intubation and caused no apparent side effects. Thus HELIOX reduces the work of breathing and may forestall respiratory failure in children with status asthmaticus, thus preventing the need for mechanical ventilation.

Administration, Inhalation↗
PubMed1997

Real-time ultrasound-guided femoral vein catheterization during cardiopulmonary resuscitation.

STUDY OBJECTIVE: To compare the use of real-time-ultrasound guidance with the standard landmark-oriented approach for obtaining femoral vein catheterization in patients requiring intravenous access during CPR. METHODS: Prospective, randomized, paired subject-controlled clinical trial in the setting of an urban teaching county hospital emergency department. The study comprised a convenience sample of 20 patients presenting with apnea and pulselessness in the ED. Each patient received bilateral femoral lines, one by ultrasound guidance and one by the landmark approach (control). Randomization determined which technique and which side would be attempted first. The following parameters were recorded: time to initial flash of blood, time to completion of catheterization, number of needle passes, and rate of arterial catheterization. CPR and Advanced Cardiac Life Support protocols were continued during both procedures. RESULTS: Real-time ultrasound-guided catheterization had a higher success rate (90% versus 65%, P = .058), a lower number of needle passes (2.3 +/- 3 versus 5.0 +/- 5, P = .0057), and a lower rate of arterial catheterization (0% versus 20%, P = .025) than the standard landmark-oriented approach. Ultrasound was also slightly faster in time to blood flash and in time to catheterization. An incidental finding of interest was that real-time ultrasound demonstrated the presence of femoral vein pulsations during CPR. CONCLUSION: Real-time ultrasound-guided femoral vein catheterization was faster and produced a lower rate of inadvertent arterial catheterization and a higher rate of success during CPR than the standard landmark-oriented approach. Also, ultrasound demonstrated that palpable femoral pulsation during CPR is venous rather than arterial.

Adult↗
PubMed1997

Effect of age and pattern of gain on induction of puberty with a progestin in beef heifers.

Crossbred heifers (n = 75) fed for rapid (R; .82 kg/d) or slow-then-rapid (SR; .41 kg/d for 90 d then .82 kg/d) postweaning gain were used to examine the effects of age or pattern of gain on induction of puberty by a progestin. At 9.5, 11.0, and 12.5 mo of age, 12 prepuberal heifers from each growth treatment received progestin (a 6-mg Norgestomet implant for 10 d) or control treatments. Induction of puberty, LH secretory profiles, and ovarian follicular characteristics were assessed in Norgestomet-treated and control heifers. Body weights of R heifers were greater (P < .01) than those of SR heifers at all ages. At 12.5 mo, more Norgestomet-treated heifers exhibited a puberal estrus within 5 d after implant removal compared with controls (82% vs 9%, respectively), but Norgestomet did not induce puberty at 9.5 or 11 mo of age (progestin x age, P < .05) in heifers of either gain pattern. Norgestomet increased (P < .01) LH pulse frequency at all ages, whereas Norgestomet increased only mean LH concentrations at 12.5 mo of age (progestin x age, P < .03). Norgestomet treatment altered (P < .01) ovarian follicular characteristics at all ages. Gain pattern did not affect (P > .1) LH secretory profiles, ovarian characteristics, or induction of puberty by Norgestomet. We conclude that progestins induce puberty by hastening the normal cascade of endocrine and ovarian events associated with spontaneous puberty. Furthermore, age, but not pattern of gain, seems to be the critical factor influencing the efficacy of progestins to induce puberty in heifers.

Aging↗
PubMed1997

Effects of a medical intensivist on patient care in a community teaching hospital.

OBJECTIVE: To determine the effect of adding a trained intensivist on patient care and educational outcomes in a community teaching hospital. MATERIAL AND METHODS: We retrospectively reviewed outcomes for patients admitted to the medical intensive-care unit (MICU) of a 270-bed community teaching hospital between July 1992 and June 1994. Mortality rates and durations of stay were determined for the year before (BD, 1992 through 1993) and the first year after (AD, 1993 through 1994) introduction of a full-time director of critical care. Performance of resident trainees on a standardized critical-care examination was measured for the same periods. RESULTS: Overall, 459 patients in the BD period were compared with 471 patients in the AD period. The mix of cases and severity of illness (acute physiology and chronic health evaluation or APACHE II scores) on admission were similar for the BD and AD periods. MICU mortality decreased from 20.9% during the BD to 14.9% during the AD period (P = 0.02), and in-hospital mortality decreased from 34.0% to 24.6% (P = 0.002). Disease-specific mortalities were lower during the AD period for most categories of illness. Detailed analysis of a subgroup of patients (those with pneumonia) demonstrated no differences in distribution of patients by gender, race, or acuity of illness (APACHE II scores). The mortality rate due to pneumonia decreased from 46% during the BD period to 31% during the AD period. This decrease was consistent across categories of APACHE II scores. From BD to AD periods, mean durations of total hospital stay decreased from 22.6 +/- 1.4 days to 17.7 +/- 1.0 days, and mean MICU stay decreased from 5.0 +/- 0.3 days to 3.9 +/- 0.3 days (P < 0.05). Critical-care in-service examination scores for 22 residents increased from 53.8 +/- 1.7% to 67.5 +/- 2.2% (P < 0.01), and AD scores were significantly higher than BD scores for residents at similar levels of training. CONCLUSION: Addition of a medical intensivist was temporally associated with improved clinical and educational outcomes in our community teaching hospital.

APACHE↗
PubMed1996

The controversy over emergency research. A review of the issues and suggestions for a resolution.

Emergency research that occurs upon critically ill subjects in circumstances that do not allow the subjects or their legally authorized representatives to grant an informed consent is currently the subject of great controversy. This Clinical Commentary reviews three issues that dominate the debate: research risk assessment, the concept of a particular kind of risk called minimal risk, and the regulations governing research on human subjects. The theses of this article are that Institutional Review Boards (IRBs) are not violating Office of Protection from Research Risks (OPRR) regulations, that Food and Drug Administration (FDA) regulations do not adequately address research design, and that emergency research fits within the ethical standards of justice, respect for autonomy, and beneficence. To defend these claims, the following points are argued: risk assessment is a moral or transscientific exercise, minimal risk refers to the increment of risk that the subject of the research faces, and that when equipoise exists between experimental and standard therapies, this state of uncertainty contributes to a study's justifications. In order to resolve the emergency research controversy, certain regulations will need to be rewritten and others reinterpreted, and a national board created to review a proposed study's clinical relevance and whether the current state of knowledge justifies a trial.

Critical Illness↗