Biomedical subjects

Miriam M Treggiari

Publications and source records attributed to Miriam M Treggiari.

5 recordsLinked to original sources

PubMed2003

Cervical sympathetic block to reverse delayed ischemic neurological deficits after aneurysmal subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: The purpose of the present study was to evaluate the feasibility and safety of a locoregional cervical sympathetic block to improve cerebral perfusion in patients suffering from cerebral vasospasm after aneurysmal subarachnoid hemorrhage. METHODS: Nine consecutive patients with symptoms of delayed ischemic deficits, induced by angiographically confirmed cerebral vasospasm, were treated with the injection of locoregional anesthesia to block the ascending cervical sympathetic chain at the level of the superior cervical ganglion. Neurological status was recorded before and after the procedure, and cerebral angiography was performed before and after the procedure. RESULTS: No complications occurred in this short series. The procedure appeared to be simple and safe. Horner's signs appeared within 12+/-0.1 minutes and lasted for an average of 6.3+/-4 hours. In all patients, improved cerebral perfusion was detected at the confirmatory angiography but without change in vessel caliber. One patient died of the complications of the initial hemorrhage, and 2 died of the consequences of the severe vasospasm despite maximal medical treatment. In all the other cases, the neurological status promptly returned to normal within 48 hours after the locoregional treatment. CONCLUSIONS: Patients with mild to moderate symptoms seem to benefit greatly from transient ipsilateral cervical sympathetic block. This simple technique may be helpful when used as an adjunct to the standard therapy to improve cerebral perfusion.

Adult↗

PubMed2003

Systematic review of the prevention of delayed ischemic neurological deficits with hypertension, hypervolemia, and hemodilution therapy following subarachnoid hemorrhage.

OBJECT: There is uncertainty about the efficacy of hypertension, hypervolemia, and hemodilution (triple-H) therapy in reducing the occurrence of delayed ischemic neurological deficits (DINDs) and death after subarachnoid hemorrhage. The authors therefore conducted a systematic review to evaluate the efficacy of triple-H prevention in decreasing the rate of clinical vasospasm, DINDs, and death. METHODS: The authors systematically reviewed studies identified based on a MEDLINE, EMBASE, and COCHRANE Register search of articles published between 1966 and 2001, and reference lists of identified articles. An independent assessment of each study's methodological quality, population, intervention, and outcomes (rates of symptomatic vasospasm, DINDs, and death) was performed. Summary relative risk estimates were calculated for the main outcomes using fixed- or random-effect models, as appropriate. Only four prospective, comparative studies with a total of 488 patients were identified. The median internal validity score was 0.5 (range 0-2); the median external validity score was 3 (range 2-6). Compared with no prevention, triple-H therapy was associated with a reduced risk of symptomatic vasospasm (relative risk [RR] 0.45, 95% confidence interval [CI] 0.32-0.65), but not DIND (RR 0.54, 95% CI 0.2-1.49). The risk of death was higher (RR 0.68, 95% CI 0.53-0.87). Sensitivity analyses including only randomized, controlled trials showed no evidence of statistically significant results for these major end points. CONCLUSIONS: The paucity of information and important limitations in the design of the studies analyzed preclude evaluation of the efficacy of triple-H prevention and formulation of any recommendations regarding its use for the prevention of cerebral vasospasm.

Blood Pressure↗

PubMed2002

Postmenopausal hormone use and skeletal fracture: does the size of the benefit decrease with increasing age?

Results of a recent meta-analysis of randomized trials suggest that, among postmenopausal women, the relative impact of hormone use in reducing the incidence of skeletal fracture declines with increasing age. We contend that: 1) the duration of the randomized trials in which older postmenopausal women were included was too short to adequately evaluate the impact of long-term hormone use on fracture risk; 2) randomized trials of hormone use in relation to a surrogate end point, bone mineral density, as well as nonrandomized studies of hormones and fracture risk, have documented a skeletal benefit associated with long-term hormone use among postmenopausal women irrespective of age; and 3) even if with increasing age there were a true decline in the relative benefit associated with the use of hormones, the size of the absolute reduction in fracture risk produced by hormone use among older postmenopausal women could be similar to or greater than that among younger postmenopausal women. For these reasons, we believe that when weighing the risks and benefits of the initiation or continuation of hormone therapy, a postmenopausal woman and her provider of health care need not consider her age when estimating the skeletal benefit such therapy can offer.

Age Factors↗

PubMed2002

Effect of increasing norepinephrine dosage on regional blood flow in a porcine model of endotoxin shock.

OBJECTIVE: To evaluate the effect of a norepinephrine-induced differential increase in mean arterial pressure on splanchnic and renal perfusion in a porcine model of volume-resuscitated endotoxic shock. DESIGN: Prospective, controlled, acute interventional study. SETTING: Animal research laboratory. SUBJECTS: Fourteen landrace pigs, seven treated with norepinephrine and seven used as endotoxemic controls. INTERVENTIONS: In an acute endotoxic shock model, norepinephrine was used to reverse hypotension in seven fluid-resuscitated pigs, anesthetized with alpha-chloralose and equipped with flow probes around the portal vein and renal artery, renal and jejunal mucosal laser Doppler flowmetry, and jejunal tonometry. Mean arterial pressure was increased by 10 and then 20 mm Hg above the shock level with norepinephrine. Seven shocked, fluid-resuscitated only animals served as the comparison group. MEASUREMENTS AND MAIN RESULTS: Measurements were performed before 2-hr endotoxin infusion and at the end of each increased level of mean arterial pressure. Raising mean arterial pressure with norepinephrine by 10 mm Hg significantly increased cardiac output, systemic oxygen extraction, and portal vein blood flow; stabilized metabolic acidosis; and tended to restore renal and jejunal mucosal flows to preshock levels. Increasing mean arterial pressure by 20 mm Hg further increased cardiac output and oxygen delivery but without improving portal vein, renal artery, and jejunal mucosal blood flows. CONCLUSIONS: Norepinephrine, administered to increase mean arterial pressure by 10 mm Hg in an acute model of volume-resuscitated endotoxic shock, improved systemic and regional perfusion. The administration of norepinephrine to increase mean arterial pressure 20 mm Hg above shock did not increase renal and splanchnic blood flows, despite an enhanced cardiac output.

Animals↗

PubMed2002

Air cysts and bronchiectasis prevail in nondependent areas in severe acute respiratory distress syndrome: a computed tomographic study of ventilator-associated changes.

OBJECTIVE: To investigate prevalence and spatial distribution of air cysts and bronchiectasis associated with mechanical ventilation in patients with severe acute respiratory distress syndrome. DESIGN: Retrospective observational study. SETTING: University hospital intensive care division. SUBJECTS: A total of 21 patients with severe acute respiratory distress syndrome requiring prolonged mechanical ventilation and undergoing thoracic computed tomographic scanning. MEASUREMENTS AND MAIN RESULTS: Lung fields were anatomically divided according to functional bronchial divisions in ten segments on each side. Air cysts, bronchiectasis, and the percentage of normal and abnormal tissue were quantified for each segment and correlated to the duration and variables of mechanical ventilation. Air cysts prevailed in nondependent compared with dependent areas (38% +/- 5% vs. 9% +/- 3%, respectively; p <.01). With mechanical ventilation longer than 10 days, the odds ratio was 13.1 (95% confidence interval, 1.4-118.7) for air cysts and for bronchiectasis 17.6 (95% confidence interval, 2.8-109.6). The amount of abnormal parenchyma correlated with duration of mechanical ventilation on high end-inspiratory pressure but not with tidal volume or minute ventilation. The presence of pneumothorax was not correlated with ventilation settings but with the amount of consolidated tissue revealed by the computed tomographic scan. CONCLUSIONS: These findings suggest predominant ventilator-induced lung damage in better ventilated areas (i.e., nondependent regions). Severity of changes revealed by computed tomographic imaging seems to be associated mainly with the high inspiratory pressures required and the length of mechanical ventilation.

APACHE↗