Biomedical subjects

R J Quigg

Publications and source records attributed to R J Quigg.

59 records · Page 4Linked to original sources

PubMed1983

Spurious hyperchloremia and decreased anion gap in hyperlipidemia.

A patient with overt lipemia presented with hyponatremia, hyperchloremia, and a negative anion gap. The hyperchloremia and negative gap resulted from overestimation of chloride levels due to a light-scattering effect in the colorimetric assay, an effect that was reproducible in vitro. In a prospective study, this effect produced substantial overestimations at even modest degrees of hyperlipemia. This effect expands the differential diagnosis of a decreased gap, adds to the list of technique-dependent artifacts in lipemia, and, if present, must be recognized for a patient's fluid and electrolyte status to be accurately defined.

Adult↗

PubMedDate not supplied

Predictors of early post-cardiac transplant exercise capacity.

BACKGROUND: This study was conducted to identify which pre- and perioperative clinical parameters were predictive of predischarge submaximal exercise capacity and early postdischarge maximal exercise capacity in cardiac transplant recipients. METHODS: We studied 24 patients (mean age = 46; 25% African American) who underwent cardiac transplantation followed by an early (immediately posttransplant) postoperative exercise training program. The patients' submaximal exercise capacity was measured at hospital discharge (25 days posttransplant) using the 6-minute distance walk test. Maximal cardiopulmonary exercise testing was done within 4 months of hospital discharge (68 days) to measure peak exercise oxygen consumption (VO2) and to estimate peak exercise capacity as measured by metabolic equivalents (METs). Six clinical variables were assessed for their relationship with predischarge submaximal exercise capacity and 10 clinical variables were evaluated for their relationship with early posttransplant maximal exercise capacity. RESULTS: Predischarge submaximal exercise capacity was correlated with postdischarge estimated METs (r = 0.43; P = 0.04). No predictors of predischarge submaximal exercise capacity were identified. Predictors of estimated peak exercise METs following discharge were younger age, longer time since resolution of rejection, and shorter postoperative hospitalization. Younger age was the only predictor of peak VO2. CONCLUSION: Postoperative physical training may improve exercise capacity early after transplantation and minimize effects of preoperative clinical factors that could negatively affect exercise capacity. Interpretation of these results, however, is limited by the small sample and absence of a nonexercising control group. Older recipients, those with a longer length of hospital stay, and shorter duration of time since resolution of rejection may be at risk of reduced early postoperative maximal exercise capacity. Identification of these predictors is important to maximize early reconditioning efforts and plan outpatient rehabilitation.

Adult↗

PubMedDate not supplied

Accuracy of estimating exercise prescription intensity in patients with left ventricular systolic dysfunction.

PURPOSE: Exercise prescription in patients with left ventricular systolic dysfunction (LVSD) is difficult. Exercising beyond ventilatory threshold (VT) can have negative physiologic effects; therefore, exercise prescribed above VT may be detrimental. A majority of cardiac rehabilitation programs use the Karvonen/heart rate reserve (HRR) method, rating of perceived exertion (RPE), and/or a percentage of oxygen consumption to prescribe exercise intensity. The purpose of this study was to determine if these methods correlate with an exercise intensity below VT in LVSD patients. METHODS: The authors studied 52 patients (37 males, 15 females; age 52 +/- 13 years; left ventricular ejection fraction 27% +/- 8%) who underwent a symptom-limited cardiopulmonary exercise test and reached VT to determine functional capacity and exercise prescription. RESULTS: Peak heart rate (HR) as well as HRR derived minimum (60%), midpoint (70%), and maximum (80%) HR were highly correlated (P < 0.001) with HR at VT. Using these three different HR cutoff formulas from HRR, 15% to 62% of patients were prescribed exercise outside the range of VT-HR +/- 10%. The midpoint (70% HRR) best predicted exercise HR in the VT-HR +/- 10% range (73% of patients). Mean oxygen consumption at VT was 83 +/- 9% of peak oxygen consumption. There was no correlation (P < 0.16) between RPE and VT. CONCLUSIONS: The Karvonen/HRR method failed to estimate HR-VT +/- 10% in a large percentage of patients with LVSD. There was no correlation between RPE and VT. Based on these data, exercise training intensity should ideally be prescribed based on the HR identified at VT using cardiopulmonary exercise testing in patients with LVSD.

Adult↗

PubMedDate not supplied

Rationale for the short term use of intravenous milrinone under hemodynamic guidance in patients with severe systolic heart failure.

Patients with severe systolic heart failure have a decrease in both number and function of cardiac beta receptors, which may result in a poor inotropic response to I.V. beta-adrenergic agonists such as dobutamine. The I.V. use of the phosphodiesterase inhibitor milrinone, which is a combined positive inotrope/vasodilator in this patient population, is a more rational choice, especially if heart failure is chronic. Many of these patients may also be referred for consideration for cardiac transplantation, for which the use of invasive hemodynamic monitoring is typically necessary to determine whether severe hemodynamic compromise and pulmonary hypertension are reversible with therapy. The use of hemodynamically guided I.V. vasodilator therapy has also been extensively described as a tool to optimize oral vasodilator therapy and predict prognosis in patients evaluated for cardiac transplantation. This review summarizes the important studies supporting the rationale for and benefits of using I.V. milrinone under hemodynamic guidance in this patient population. (c)2000 by CHF, Inc.

Journal Article↗

PubMedDate not supplied

Reversal of severe cardiac systolic dysfunction caused by pheochromocytoma in a heart transplant candidate.

Whenever a patient is evaluated as a possible candidate for heart transplantation, potential causes of reversible cardiomyopathy must always be considered. Although rate, it is well-known that pheochromocytoma can result in a dilated cardiomyopathy, which can be partially or completely reversible. We report a case of a 33-year-old woman with heart failure that was caused by a severe dilated cardiomyopathy who was referred for urgent heart transplant evaluation. The diagnosis of bilateral adrenal pheochromocytomas was made, and within 3 weeks of medical therapy, left ventricular systolic dysfunction completely reversed, avoiding the need for heart transplantation. The patient later underwent successful adrenalectomy. Unique features of this case of pheochromocytoma-induced cardiomyopathy include (1) serial norepinephine measurements over 3 weeks documenting the efficacy of medical therapy, (2) unique cutaneous manifestations that resolved with medical therapy, and (3) familial multiple endocrine neoplasia syndrome with medullary carcinoma of the thyroid in three generations of this patient's family.

Adrenal Gland Neoplasms↗