Biomedical subjects

J D Santamaria

Publications and source records attributed to J D Santamaria.

10 recordsLinked to original sources

PubMed1999

A controlled trial of low-molecular-weight heparin (dalteparin) versus unfractionated heparin as anticoagulant during continuous venovenous hemodialysis with filtration.

OBJECTIVE: To compare the efficacy, safety, and cost of fixed-dose low-molecular-weight heparin (dalteparin) with adjusted-dose unfractionated heparin as anticoagulant for continuous hemofiltration. DESIGN: Prospective, randomized, controlled clinical trial. SETTING: University-affiliated adult intensive care unit PATIENTS: All patients requiring continuous hemofiltration for acute renal failure or systemic inflammatory response syndrome (SIRS) were eligible. Fifty-seven patients were enrolled. Eleven were excluded, seven because of major protocol violations and four died before hemofiltration. INTERVENTIONS: Patients received continuous venovenous hemodialysis with filtration with prefilter replacement at 500 mL/hr and countercurrent dialysate at 1000 mL/hr. Filters were primed with normal saline containing anticoagulant. Dalteparin-treated patients received a commencement bolus of 20 units/kg and a maintenance infusion at 10 units/kg/hr. Heparin-treated patients received a commencement bolus of 2000-5000 units and a maintenance infusion at 10 units/kg/hr, titrated to achieve an activated partial thromboplastin time in the patient of 70-80 secs. MEASUREMENTS AND MAIN RESULTS: The primary outcome measure--time to failure of the hemofilter--was compared using survival analysis. Twenty-two patients (13 with acute renal failure and nine with SIRS; total, 41 filters) were randomized to heparin. Twenty-five patients (16 with acute renal failure and nine with SIRS; total, 41 filters) were randomized to dalteparin. Mean (SE) activated partial thromboplastin time in the heparin group was 79 (4.3) secs. Mean (SE) anti-factor-Xa activity in the six patients given dalteparin who were assayed was 0.49 (0.07). Mean (SE) prehemofiltration platelet count was 225 (35.5) x 10(9) for heparin and 178 (18.1) x 10(9) for dalteparin (p = .24, unpaired Student's t-test). Mean (SE) prehemofiltration hemoglobin was 11.4 (0.61) g/dL for heparin and 10.6 (0.38) g/dL for dalteparin (p = .31, unpaired Student's t-test). PRIMARY OUTCOME: There was no significant difference in the time to failure between the two groups (p = .75, log rank test). For dalteparin, Kaplan-Meier (K-M) mean (SE) time to failure of the hemofilter was 46.8 (5.03) hrs. For heparin, K-M mean (SE) time to failure was 51.7 (7.51) hrs. The 95% CI for difference in mean time to failure was -13 to 23 hrs. The power of this study to detect a 50% change in filter life was >90%. SECONDARY OUTCOMES: Mean (SE) reduction in platelet count during hemofiltration was 63 (25.8) x 10(9) for heparin and 41.8 (26.6) x 10(9) for dalteparin (p = .57, unpaired Student's t-test). Eight patients given dalteparin and four patients given heparin had screening for heparin-induced thrombocytopenia; three of the dalteparin patients and one of the heparin patients were positive (p = 1.0, Fisher's exact test). There were three episodes of trivial bleeding and two episodes of significant bleeding for dalteparin, and there were three episodes of trivial bleeding and four episodes of significant bleeding for heparin (p = .53, chi-square test). The mean (SE) decrease in hemoglobin concentration during hemofiltration was 0.51 (0.54) g/dL for heparin and 0.28 (0.49) g/dL for dalteparin (p = .75, unpaired Student's t-test). The mean (SE) packed-cell transfusion volume during hemofiltration was 309 (128) mL for heparin and 290 (87) mL for dalteparin (p = .90, unpaired Student's t-test). Daily costs, including coagulation assays, of hemofiltration were approximately 10% higher using dalteparin than with heparin. CONCLUSIONS: Fixed-dose dalteparin provided identical filter life, comparable safety, but increased total daily cost compared with adjusted-dose heparin. Unfractionated heparin remains our anticoagulant of choice for continuous hemofiltration in intensive care.

Acute Kidney Injury↗

PubMed1998

Early extubation following coronary artery bypass surgery: a prospective randomized controlled trial. The Fast Track Cardiac Care Team.

STUDY OBJECTIVES: To determine the safety of early extubation (EE) after coronary artery surgery. DESIGN: Prospective randomized controlled trial. SETTING: The cardiac surgery operating room and ICU of a university-affiliated teaching hospital. PATIENTS: One hundred eligible patients presenting for elective coronary artery surgery. INTERVENTIONS: Patients randomized to the EE group were administered a reduced dose of fentanyl (15 microg/kg) and an anesthetic compatible with EE, while patients randomized to the conventional extubation (CE) group were given fentanyl (50 microg/kg). MEASUREMENTS AND RESULTS: The time to extubation in the EE group (median, 240 min; range, 30 to 930 min) was significantly less than the CE group (median, 420 min; range, 125 to 1,140 min) (p<0.01). Twenty patients were withdrawn from the study according to protocol guidelines. There were no cases of reintubation or complications attributable to EE. CONCLUSIONS: By using an appropriate anesthetic technique and postoperative management, EE can be achieved following coronary artery bypass surgery without major complications.

Anesthesia↗

PubMed1995

Current status of coronary artery bypass grafting in patients 70 years of age and older.

One hundred and seventy patients 70 years of age and older underwent isolated coronary artery bypass grafting (CABG) from January 1990 to December 1991 at St. Vincent's Hospital, Melbourne, Australia. The clinical records of these patients were analysed to investigate whether elderly patients could undergo safe coronary artery surgery and to determine the factors affecting the outcome. The 30 day or in-hospital mortality was 2.9% (5/170), with 80% (4/5) of the deaths due to cardiac causes. Major postoperative complications occurred in 22.3% (38/170) patients. The median postoperative hospital stay for the patients was 8 days (range 3-103 days). Univariate analysis identified hypertension and female gender as pre-operative risk factors and intraaortic balloon pump, prolonged ventilation, infarct, tamponade, need for inotropes, renal failure and a high APACHE II scores in the intensive care unit as postoperative significant risk factors for operative mortality. There was a trend towards increased mortality with emergency operations; the operative mortality was 2.1% (2/97) for elective operations, 3.1% (2/64) in urgent cases and 11.1% (1/9) for emergencies. Multivariate logistic regression analysis identified prolonged mechanical ventilation, perioperative infarct and APACHE II score as significant independent predictors of mortality. The low operative mortality indicates that elderly patients can undergo safe revascularization. A high incidence of complications necessitates careful monitoring but age per se should not be considered a contraindication to isolated CABG.

Age Factors↗

PubMed1992

Plasma apolipoprotein (a) is increased in type 2 (non-insulin-dependent) diabetic patients with microalbuminuria.

Patients with Type 2 (non-insulin-dependent) diabetes mellitus complicated by microalbuminuria or albuminuria, have an increased risk of developing macrovascular disease and of early mortality. Because lipoprotein abnormalities have been associated with diabetic nephropathy, this study tested the hypothesis that levels of apolipoprotein (a) are elevated in patients with Type 2 diabetes and increased levels of urinary albumin loss. Levels of apolipoprotein (a) in diabetic patients with microalbuminuria (n = 26, geometric mean 195 U/l, 95% confidence interval 117-324) and albuminuria (n = 19, 281 U/l, 165-479) were higher than in non-diabetic control subjects (n = 140, 107 U/l, 85-134, p < 0.05), and in the albuminuric group than diabetic patients without urinary albumin loss (n = 58, 114 U/l, 76-169, p < 0.05). Patients with microalbuminuria and albuminuria had levels comparable with patients undergoing elective coronary artery graft surgery (n = 40, 193 U/l, 126-298). Apolipoprotein (a) levels were higher in diabetic patients with macrovascular disease than in those without (n = 49, 209 U/l, 143-306 vs n = 54, 116 U/l, 78-173, p < 0.05). These preliminary results suggest that raised apolipoprotein (a) levels of Type 2 diabetic patients with microalbuminuria and albuminuria may contribute to their propensity to macrovascular disease and early mortality.

Aged↗

PubMed1992

Circulating PTH and PTHrP levels before and after treatment of tumor induced hypercalcemia with Pamidronate Disodium (APD).

The effect of lowering ionized calcium on circulating parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) was assessed in twenty patients with hypercalcemia of malignancy following treatment with Pamidronate Disodium. Ionized calcium levels fell rapidly in all treated patients. PTH concentrations were initially suppressed below normal in 18 patients, but rose from 0.48 +/- 0.42 pmol/L to 3.63 +/- 3.13 pmol/L (p less than 0.01) after treatment, reaching higher than normal values in some patients even in the presence of persistent hypercalcemia. PTHrP concentrations did not change significantly after treatment. These findings are consistent with an increased sensitivity of parathyroid tissue to changes in ionized calcium following prolonged exposure to hypercalcemia. Regulation of tumor secretion of PTHrP by calcium was not apparent within the range of calcium concentrations in this study.

Calcium↗

PubMed1988

Reversible reproductive dysfunction in men with obstructive sleep apnoea.

A central, reversible decrease in male sexual function appears related to some aspect of obstructive sleep apnoea (OSA). Lower serum testosterone (T) levels were documented in 15 men with OSA versus nine snorers (no OSA), (9.18 +/- 0.92 vs 11.55 +/- 0.90 nmol/l, mean +/- SEM), P less than 0.05 in a consecutive case series of 24 men referred for diagnostic overnight sleep studies. Gonadotrophins did not differ between the two groups. Although the men with OSA did not differ in body mass index (BMI) or weight from the snorers, they were older (51 +/- 3.9 vs 44 +/- 3.1 years), P less than 0.02. Serum T did not correlate with age, but was correlated with minimum nocturnal arterial oxygen saturation (Min SaO2) (r = 0.589), P less than 0.02. A prospective controlled trial of uvulopalatopharyngoplasty therapy (UPP) for OSA in 12 subsequent subjects showed reproductive improvement which was parallel with improved apnoea at 3 months postsurgery. T increased (13.31 +/- 1.07 to 16.59 +/- 0.72 nmol/l), P less than 0.02, without significant changes in BMI, serum PRL, LH or FSH. All seven of the men who reported decreased sexual interest prior to surgery felt their libido and sexual functioning had returned to normal 3 months following UPP. Some aspect of OSA in men appears to produce a reversible hypothalamic-pituitary reproductive dysfunction.

Adult↗

PubMed1986

Facial morphology and obstructive sleep apnea.

In a sample of 25 adult male subjects with moderate to severe obstructive sleep apnea, the interaction among craniofacial, airway, tongue, and hyoid variables was quantified by means of a canonical correlation analysis. One lateral cephalometric radiograph with the teeth in occlusion was obtained for each subject together with overnight polysomnographic measurements before the initiation of therapy. A principal component analysis reduced the data base and one significant canonical correlation (r1 = 0.994) was identified for the 22 variables. Sleep apnea subjects showed a posteriorly positioned maxilla and mandible, a steep occlusal plane, overerupted maxillary and mandibular teeth, proclined incisors, a steep mandibular plane, a large gonial angle, high upper and lower facial heights, and an anterior open bite in association with a long tongue and a posteriorly placed pharyngeal wall. A multivariate statistical analysis extracted clinically significant associations among craniofacial, tongue, and airway variables. Subjects with sleep apnea demonstrated several alterations in craniofacial form that may reduce the upper airway dimensions and subsequently impair upper airway stability.

Adult↗

PubMed1985

Patient comfort and plasma lignocaine concentrations during fibreoptic bronchoscopy.

In a preliminary prospective study, eleven outpatients undergoing fibreoptic bronchoscopy using a titrated dose of topical lignocaine anaesthesia were studied. Patient comfort, lignocaine dosage and resultant plasma concentrations were measured at four stages during the procedure. Large total doses, mean 512 (SD 55) mg lignocaine, were frequent and systemic absorption was unpredictable with two patients having plasma concentrations in the toxic range (greater than 5 micrograms/ml). Peak plasma concentrations, mean 2.3 (SD 1.4) micrograms/ml, occurred 30 to 40 minutes after commencement of topical application and coincided with completion of the procedure. No correlation was found between the individual dose of lignocaine administered and either the resultant plasma concentration or patient comfort scores. In an effort to minimise potential lignocaine toxicity, a fixed total dose technique (lignocaine 370 mg) was studied in a further twenty-one patients. No change in patient comfort scores and no toxic plasma concentrations were observed. Mean completion plasma concentration was 2.0 (SD 1.0) micrograms/ml. No clinical toxicity was observed in either group. Fibreoptic bronchoscopy in both groups using topical lignocaine anaesthesia without premedication or intravenous supplementation was well tolerated.

Administration, Oral↗

PubMed1984

The potential bronchodilator action of verapamil.

Although calcium antagonists such as verapamil are used primarily in cardiovascular disease, they appear to relax smooth muscle generally. Therefore, the possibility that verapamil might have bronchodilator properties was explored using the guinea-pig tracheal ring technique. Verapamil was found to produce considerable tracheal smooth muscle relaxation from a threshold concentration of 2 X 10(-7) M and with maximum effect at 10(-3) M. The responses to the contractile agonists histamine and prostaglandin F2 alpha and especially methacholine and serotonin were substantially reduced by prior administration of verapamil. Verapamil 2 X 10(-4) M was equally effective as isoprenaline 10(-8) M in producing 50% maximum direct relaxation but was more effective than isoprenaline as an antagonist of the contractile agonists, methacholine, histamine and serotonin, but not prostaglandin F2 alpha. Verapamil abolished the contractile responses to barium chloride. It is concluded that, although verapamil was not very potent as a direct bronchodilator, it could potentially be of prophylactic benefit in asthma because of its efficacy as an antagonist of common contractile agonists.

Animals↗

PubMedDate not supplied

Optimisation of respiratory function.

OBJECTIVE: To apply pathophysiological principles in the management of patients with acute and chronic respiratory impairment. CONCLUSIONS: Knowledge of the pathophysiology of respiratory disorders is a key element in treatment of patients with impending or established respiratory failure. Therapies to improve and support abnormal gas exchange will minimise the complications of hypoxia and interventions to optimise ventilation and work of breathing may obviate the need for mechanical ventilation.

Humans↗