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Biomedical subjects

Allen R Kunselman

Publications and source records attributed to Allen R Kunselman.

At least 19 recordsLinked to original sources
PubMed2007

Changes in urine markers and symptoms after bladder distention for interstitial cystitis.

PURPOSE: We evaluated changes in urine markers and symptom scores after bladder distention in patients with interstitial cystitis. MATERIALS AND METHODS: Study subjects were 33 new patients who had undergone no prior interstitial cystitis treatment. Urine specimens were taken before and 1 month after bladder distention. University of Wisconsin symptom scores were done the same day as the urine specimen collection. Urine marker levels and symptom scores before and after distention were compared. Changes in markers were tested for associations with changes in symptom scores and other markers. Markers and specific symptoms before distention were tested for their association with post-distention symptom improvement. RESULTS: After distention the median total University of Wisconsin score decreased significantly (28.5 before, 20 after, p <0.001). A total of 12 patients (36%) had at least 30% improvement in University of Wisconsin score, and 8 patients (24%) had at least 50% improvement. No pre-distention markers or symptoms predicted which patients would have a good response. There were 2 urine markers that improved significantly after distention: anti-proliferative factor activity (median -96% before, -17% after, p <0.001) and heparin-binding epidermal growth factor-like growth factor levels (median 0.34 ng/mg creatinine before, 4.1 after, p <0.001). None of the changes in urine markers associated with changes in symptom scores. CONCLUSIONS: The median symptom score for newly diagnosed patients with interstitial cystitis decreased after distention, but only a minority of patients had at least 30% symptom improvement. Bladder distention altered urine anti-proliferative factor activity and heparin-binding epidermal growth factor-like growth factor levels toward normal, but the mechanism of symptom relief after distention is still unknown.

Adult↗
PubMed2006

Association of obesity with treatment outcomes in ovulatory infertile women undergoing superovulation and intrauterine insemination.

OBJECTIVE: To evaluate the association between obesity and the outcome of superovulation and intrauterine insemination (IUI) in infertile ovulatory women. DESIGN: Retrospective chart review. SETTING: University-based infertility clinic. PATIENT(S): Three hundred thirty-three ovulatory women, grouped by body mass index (BMI) categories, who received superovulation and IUI for treatment of infertility. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S) PRIMARY OUTCOME: cycle fecundity. SECONDARY OUTCOMES: total dose of gonadotropins, serum level of E(2), and number of follicles >or=17 mm on the day of hCG injection. RESULT(S): Adjusted cycle fecundity was not different among BMI groups (underweight: 0.14 [95% CI: {0.07, 0.29}], normal weight: 0.12 [95% CI: {0.09, 0.16}], overweight: 0.17 [95% CI: {0.12, 0.24}], and obese: 0.14 [95% CI: {0.08, 0.23}]). Adjusted total gonadotropin dose (IU/cycle) was greater in obese women than in underweight or normal-weight women. Although the numbers of large follicles were not different, E(2) levels (pg/mL) were lower in obese women than in normal-weight and overweight women. CONCLUSION(S): Our sample of ovulatory infertile women demonstrated that treatment-related cycle fecundity is unaffected by obesity. We conclude that obese, infertile ovulatory women require a greater dose of gonadotropins to achieve similar levels of superovulation than normal, underweight or overweight women.

Adult↗
PubMed2006

Use of the internet to enhance infectious disease surveillance and outbreak investigation.

Modernization of electronic communication systems to facilitate infectious disease surveillance and outbreak investigation became a priority after the 2001 anthrax attacks. However, the extent to which communicable disease investigators are using web-based information resources, e-mail notifications, or secure information exchange systems to facilitate surveillance is unknown. To address this question, we conducted a survey in 2004 of state and local communicable disease investigators responsible for infectious disease surveillance and outbreak investigation in three states. The majority (70.7%) of the 297 respondents accessed the Internet for information regarding infectious disease surveillance and outbreaks at least weekly. Most (74%) respondents who searched for information from the Centers for Disease Control and Prevention (CDC) website reported that they found what they were looking for 75-100% of the time, compared with 54% who found the information from their state health department websites 75-100% of the time. One-third of respondents read e-mail notifications regarding outbreaks under investigation in their state less frequently than monthly; 34% of those enrolled in CDC's Epidemic Information Exchange (Epi-X) read e-mail notifications of new reports less frequently than monthly. Forty-seven (18%) respondents read ProMED-mail at least monthly, while 46% indicated they had never consulted MEDLINE/PubMed. Some progress has been made in use of the Internet to facilitate communication in infectious disease surveillance and outbreak investigation. Addressing barriers to access and usability of new information systems in conjunction with training and technical support could enhance infectious disease surveillance and timely investigation of outbreaks and bioterrorism events.

Centers for Disease Control and Prevention, U.S.↗
PubMed2005

Changes in glucose tolerance over time in women with polycystic ovary syndrome: a controlled study.

We performed this study to access the changes in glucose tolerance over time in a group of women with polycystic ovary syndrome (PCOS) (n = 71) and control women (n = 23) with regular menstrual cycles and baseline normal glucose tolerance. Mean follow-up was between 2 and 3 yr for both groups (PCOS 2.5 +/- 1.7 yr; controls 2.9 +/- 2.1 yr). Based on World Health Organization glucose tolerance categories, there was no significant difference in the prevalence of glucose intolerance at follow-up in the PCOS group. In the PCOS group, 25 (37%) had impaired glucose tolerance (IGT) and seven (10%) had type 2 diabetes mellitus at baseline, compared with 30 (45%) and 10 (15%), respectively, at follow-up. There were also no differences within groups (PCOS or control) or between groups (PCOS vs. control) in the oral glucose tolerance test-derived measure of insulin sensitivity, but in the women with PCOS who converted to either IGT or type 2 diabetes mellitus, there was a significant decrease (P < 0.0001). At the follow-up visit, the mean glycohemoglobin level was 6.1 +/- 0.9% in women with PCOS vs. 5.3 +/- 0.7% in the control women (P < 0.001). Women with PCOS and baseline IGT had a low conversion risk of 6% to type 2 diabetes over approximately 3 yr, or 2% per year. The effect of PCOS, given normal glucose tolerance (NGT) at baseline, is more pronounced with 16% conversion to IGT per year. Our study supports that women with PCOS (especially with NGT) should be periodically rescreened for diabetes due to worsening glucose intolerance over time, but this interval may be over several years and not annually.

Adult↗
PubMed2005

Estimation of the intervention effect in a non-randomized study with pre- and post-mismeasured binary responses.

In non-randomized clinical studies, the regression phenomenon can confound interpretation of the effectiveness of an intervention. The regression effect arises due to daily variation and/or misclassification of the biologic marker used in selection as well as in the assessment of the intervention effect. We consider a scenario in which the selection criterion for a subject's participation in the study is such that he/she must have a positive diagnostic test at screening. The disease status is then reassessed at the end of intervention. Thus, two repeated measurements of a binary disease outcome are available, with only selected subjects having a second measurement upon follow-up. We propose methods for estimating the change in event probability resulting from implementing the intervention while adjusting for the misclassification that produces the regression effect. We extend this approach to estimation of both the placebo and intervention effects in placebo-controlled studies designed with a misclassified binary outcome. Analyses of two biomedical studies are used for illustration.

Acoustic Impedance Tests↗
PubMed2005

Polycystic ovaries are common in women with hyperandrogenic chronic anovulation but do not predict metabolic or reproductive phenotype.

Polycystic ovary syndrome (PCOS) is a heterogeneous disorder of unexplained hyperandrogenic chronic anovulation. Experts have recommended including the morphology and volume of the ovary in the diagnostic criteria for PCOS. We performed this study to determine whether there was an association between the morphology and size of the ovaries and markers of insulin sensitivity as determined by dynamic testing within women with PCOS or compared with a group of control women. We then examined reproductive parameters. We studied 88 unrelated PCOS women and 21 control women, aged 17-45 yr. All were in the early follicular phase or its equivalent (no follicle with > 10 mm diameter and anovulatory serum progesterone level < 3 ng/ml). Subjects underwent on the same day a phlebotomy for baseline hormones, a 2-h oral glucose tolerance test, and transvaginal ultrasound to determine the morphology and volume of the ovaries. Ninety-five percent (84 of 88) of women with PCOS and 48% (10 of 21) of the control women had polycystic ovaries using the criteria of at least one ovary greater than 10 cm3 (PCOV) and/or polycystic ovary morphology (PCOM) using the criteria of 10 or more peripheral follicular cysts 8 mm in diameter or less in one plane along with increased central ovarian stroma. PCOM was a better discriminator than PCOV between PCOS and control women. The odds of women with PCOS having PCOM were elevated 50-fold compared with controls (odds ratio, 50; 95% confidence interval, 10-240; P < 0.0001), whereas the odds of PCOV were elevated 5-fold in women with PCOS (odds ratio, 4.6; 95% confidence interval, 1.7-12.6; P = 0.003). Neither the insulin sensitivity index, fasting or 2-h values, or any integrated measures of glucose and insulin varied in women according to either morphology or volume, nor was there an association with circulating androgen levels. Women with PCOS and PCOM had lower FSH levels than women with PCOS and non-PCOM. Women with PCOS and PCOV had a higher LH to FSH ratio than women without PCOV and PCOS. These data support the hypothesis that polycystic ovaries are an abnormal finding. However, neither the morphology nor the volume of the ovaries is associated with distinctive metabolic or reproductive phenotypes in women with PCOS.

Adolescent↗
PubMed2005

Patients' request for and emergency physicians' prescription of antimicrobial prophylaxis for anthrax during the 2001 bioterrorism-related outbreak.

BACKGROUND: Inappropriate use of antibiotics by individuals worried about biological agent exposures during bioterrorism events is an important public health concern. However, little is documented about the extent to which individuals with self-identified risk of anthrax exposure approached physicians for antimicrobial prophylaxis during the 2001 bioterrorism attacks in the United States. METHODS: We conducted a telephone survey of randomly selected members of the Pennsylvania Chapter of the American College of Emergency Physicians to assess patients' request for and emergency physicians' prescription of antimicrobial agents during the 2001 anthrax attacks. RESULTS: Ninety-seven physicians completed the survey. Sixty-four (66%) respondents had received requests from patients for anthrax prophylaxis; 16 (25%) of these physicians prescribed antibiotics to a total of 23 patients. Ten physicians prescribed ciprofloxacin while 8 physicians prescribed doxycycline. CONCLUSION: During the 2001 bioterrorist attacks, the majority of the emergency physicians we surveyed encountered patients who requested anthrax prophylaxis. Public fears may lead to a high demand for antibiotic prophylaxis during bioterrorism events. Elucidation of the relationship between public health response to outbreaks and outcomes would yield insights to ease burden on frontline clinicians and guide strategies to control inappropriate antibiotic allocation during bioterrorist events.

Anthrax↗
PubMed2005

Estimating live birth rates after ovulation induction in polycystic ovary syndrome: sample size calculations for the pregnancy in polycystic ovary syndrome trial.

Polycystic ovary syndrome (PCOS) affects approximately 5% of the female population, and is a leading cause of infertility, primarily secondary to anovulation. Clomiphene citrate has been standard therapy for ovulation induction in patients seeking pregnancy, but recent evidence suggests that insulin sensitizing agents such as metformin may also be effective. The National Institute of Child Health and Human Development's Reproductive Medicine Network has begun a randomized, double-blind trial of clomiphene vs. metformin vs. clomiphene plus metformin for the induction of ovulation in patients with PCOS seeking pregnancy, with live birth rate as the primary outcome. Because the available literature was largely limited to surrogate outcomes such as ovulation and pregnancy rates, we created a Markov model to derive estimates of likely live birth rates in each arm. Using these estimates, we then constructed an algorithm that allowed only two formal comparisons between the three arms. First, we assumed that combination therapy would have to be superior to the next best single-agent therapy in order to be preferred, because of complexity, costs, increased side effects, etc. If combination therapy is not superior to the next best single agent, then the only other comparison of interest is between the two single agent therapies. Because the third possible comparison, between the best and worst of the three therapies, is not clinically relevant, it can be eliminated from formal statistical consideration, with subsequent reduction in sample size. Based on the opinion of the Network Steering Committee that a 15% absolute difference in live birth rates would be clinically relevant, our methodology resulted in a sample size of 226 per arm, or a total of 678 subjects. The PPCOS trial should definitively answer the question of the relative efficacy of metformin, clomiphene, and combination therapy in the treatment of infertile women with PCOS.

Adolescent↗
PubMed2005

Do the National Institute of Diabetes and Digestive and Kidney Diseases cystoscopic criteria associate with other clinical and objective features of interstitial cystitis?

PURPOSE: We compared urine markers, bladder biopsy findings and clinical features of patients with symptoms of interstitial cystitis (IC) who did or did not meet the cystoscopic criteria defined by the National Institute of Diabetes and Digestive and Kidney Diseases. MATERIALS AND METHODS: Urine markers and symptom questionnaires were measured before and 1 month after bladder distention for IC. Bladder biopsies were taken at the time of distention. At distention patients were defined as meeting or not meeting the National Institute of Diabetes and Digestive and Kidney Diseases established cystoscopic criteria for IC. The 2 patient groups were compared. RESULTS: Urine marker levels were similar for the 2 groups, including antiproliferative factor, epidermal growth factor, heparin binding epidermal growth factor-like growth factor, cyclic guanosine monophosphate, interleukins 6 and 8, and methylhistamine. Bladder biopsy features were similar for the 2 groups. Bladder capacity with the patients under anesthesia was higher in those who did not meet the criteria (median 750 vs 1,000 ml, p = 0.005). Median age at symptom onset was 26 years in both groups. On the University of Wisconsin symptom scale patients who met the criteria had higher scores for daytime frequency (p = 0.002) and nocturia (p = 0.01). Symptom characteristics and symptom response after bladder distention were similar for the 2 groups. CONCLUSIONS: Patients who met the cystoscopic criteria had worse daytime frequency and nocturia, and lower bladder capacity under anesthesia. However, the 2 groups had similar urine markers and bladder biopsy findings. The cystoscopic criteria do not appear to identify a distinct pathophysiological subset of patients with IC symptoms.

Adult↗
PubMed2004

Renal blood flow in heart failure patients during exercise.

During exercise, reflex renal vasoconstriction maintains blood pressure and helps in redistributing blood flow to the contracting muscle. Exercise intolerance in heart failure (HF) is thought to involve diminished perfusion in active muscle. We studied the temporal relationship between static handgrip (HG) and renal blood flow velocity (RBV; duplex ultrasound) in 10 HF and in 9 matched controls during 3 muscle contraction paradigms. Fatiguing HG (protocol 1) at 40% of maximum voluntary contraction led to a greater reduction in RBV in HF compared with controls (group main effect: P <0.05). The reduction in RBV early in HG tended to be more prominent during the early phases of protocol 1. Similar RBV was observed in the two groups during post-HG circulatory arrest (isolating muscle metaboreflex). Short bouts (15 s) of HG at graded intensities (protocol 2; engages muscle mechanoreflex and/or central command) led to greater reductions in RBV in HF than controls (P <0.03). Protocol 3, voluntary and involuntary biceps contraction (eliminates central command), led to similar increases in renal vasoconstriction in HF (n=4). Greater reductions in RBV were found in HF than in controls during the early phases of exercise. This effect was not likely due to a metaboreflex or central command. Thus our data suggest that muscle mechanoreflex activity is enhanced in HF and serves to vigorously vasoconstrict the kidney. We believe this compensatory mechanism helps preserve blood flow to exercising muscle in HF.

Blood Flow Velocity↗
PubMed2004

Is urine methylhistamine a useful marker for interstitial cystitis?

PURPOSE: We determined whether urine methylhistamine (MH) is associated with other clinical features and bladder biopsy findings in interstitial cystitis (IC). MATERIALS AND METHODS: Urine MH and University of Wisconsin symptom scores were measured before and 1 month after bladder distention for IC. Bladder biopsies were done at the time of distention. In new patients with IC who met cystoscopic criteria urine MH was compared before and after distention, and changes in urine MH were compared with changes in symptom scores. Pre-distention urine MH was tested for associations with the results of a symptom questionnaire, symptom response after distention, cystoscopic findings and bladder biopsy findings. RESULTS: There were no significant associations between urine MH and symptom scores, response to bladder distention, cystoscopic findings or bladder biopsy features, including mast cell count by tryptase staining. Urine MH was similar in new patients with IC who did vs did not meet cystoscopic criteria. Urine MH was similar in new vs chronically treated patients with IC. CONCLUSIONS: Urine MH is unlikely to be useful as an objective marker of the response to bladder distention, as a method to predict which patients will respond to bladder distention or as a noninvasive substitute for bladder biopsy and mast cell counts by tryptase staining.

Adult↗
PubMed2003

Aging and the exercise pressor reflex in humans.

BACKGROUND: Blood flow limitation to exercising muscles engages the muscle reflex during exercise, evoking an increase in heart rate (HR), blood pressure (BP), and muscle sympathetic nerve activity (MSNA). METHODS AND RESULTS: In the current study, we examined forearm flow and autonomic responses to ischemic handgrip in young and older subjects. We studied 6 younger subjects (mean age 23.5+/-2.2 years) and 7 older subjects (mean age 65.0+/-2.4 years). Subjects performed rhythmic handgrip (thirty 1-sec contractions/min) at 30% maximal voluntary contraction during six 1-minute stages: freely perfused exercise (E1) and exercise with forearm pressure of +10, +20, +30, +40, and +50 mm Hg (E2 through E6). We measured HR, BP, MSNA, forearm flow velocity, forearm venous oxygen saturation, H(+), and lactate. Compared with E1, ischemic exercise (E2 through E6) increased HR, BP, and MSNA, reduced forearm velocity, lowered venous oxygen saturation, and raised venous lactate and H(+). Compared with the younger subjects, the older subjects had attenuated BP at E6, attenuated MSNA indices (%(Delta)bursts, bursts/100 heart beats and signal averaged MSNA), attenuated H(+) at E6, a trend toward higher levels of oxygen saturation, and similar forearm velocity and HR responses. CONCLUSIONS: Aging attenuates the muscle reflex.

Adult↗
PubMed2002

Impaired vasodilator responses in obstructive sleep apnea are improved with continuous positive airway pressure therapy.

Obstructive sleep apnea causes cardiovascular morbidity and premature death. Potential links between sleep apnea and cardiovascular complications are chronically elevated activity of the sympathetic nervous system and abnormal vascular function. To explore vascular function, we determined the reactive hyperemic blood flow (RHBF) responses to 10 minutes of forearm arterial occlusion (plethysmography), blood pressure, and muscle sympathetic nerve activity (MSNA, microneurography) in eight patients with sleep apnea and in nine nonapneic control subjects. Peak RHBF and vascular conductance were markedly attenuated in sleep apnea compared with control subjects (p < 0.05). Seven sleep apnea patients were retested after at least two weeks of continuous positive airway pressure (CPAP) therapy. MSNA decreased after CPAP therapy (p < 0.05, n = 6), whereas blood pressure did not change. After CPAP therapy, peak RHBF and vascular conductance were increased compared with before treatment (p < 0.05; n = 7). Thus, vascular function is abnormal in sleep apnea and is improved by CPAP therapy. Furthermore, effective CPAP therapy decreases sympathetic activity in sleep apnea. Thus, sympathoexcitation and abnormal vascular function in patients with sleep apnea appear to be linked to the repetitive nocturnal apneic events.

Adult↗
PubMed2002

Self-selected women with polycystic ovary syndrome are reproductively and metabolically abnormal and undertreated.

OBJECTIVE: To determine whether self-selected women with polycystic ovary syndrome (PCOS) are abnormal compared with a control population. DESIGN: Case-control. SETTING: Support group meeting organized and initiated by patients. PATIENT(S): Forty-five self-selected women with PCOS and 80 control women. INTERVENTION(S): Self-selected women with PCOS at a peer support conference completed a questionnaire, had a brief physical, and gave a fasting blood sample. MAIN OUTCOME MEASURE(S): Historical, biometric, and assay results. RESULT(S): Sixty percent of the women attending the conference participated in the study. Most had been diagnosed with PCOS on the basis of ovarian morphology (35%). They were more likely to be nulliparous and have a history of oligomenorrhea (96%). They were hyperandrogenemic (significantly elevated testosterone and DHEAS levels) compared with control women. Self-selected women with PCOS displayed multiple metabolic abnormalities compared with control women, including elevations in blood pressure, waist-hip ratio, fasting insulin, fasting total cholesterol, and fasting low-density lipoprotein cholesterol levels, as well as a significant decrease in fasting glucose-insulin ratio and high-density lipoprotein cholesterol levels. CONCLUSION(S): Self-selected women with PCOS have reproductive and metabolic abnormalities. The majority of these women received inadequate treatment despite having risk factors for endometrial cancer, diabetes, and/or heart disease. Our study also suggests that women attending or participating in a PCOS support group are willing and likely to participate in clinical studies.

Adult↗
PubMed2002

Attenuated sympathetic nerve responses after 24 hours of bed rest.

Bed rest reduces orthostatic tolerance. Despite decades of study, the cause of this phenomenon remains unclear. In this report we examined hemodynamic and sympathetic nerve responses to graded lower body negative pressure (LBNP) before and after 24 h of bed rest. LBNP allows for baroreceptor disengagement in a graded fashion. We measured heart rate (HR), cardiac output (HR x stroke volume obtained by echo Doppler), and muscle sympathetic nerve activity (MSNA) during a progressive and graded LBNP paradigm. Negative pressure was increased by 10 mmHg every 3 min until presyncope or completion of -60 mmHg. After bed rest, LBNP tolerance was reduced in 11 of 13 subjects (P <.023), HR was greater (P <.002), cardiac output was unchanged, and the ability to augment MSNA at high levels of LBNP was reduced (rate of rise for 30- to 60-mmHg LBNP before bed rest 0.073 bursts x min(-1) x mmHg(-1); after bed rest 0.035 bursts x min(-1) x mmHg(-1); P < 0.016). These findings suggest that 24 h of bed rest reduces sympathetic nerve responses to LBNP.

Adult↗
PubMed2002

Elevated dehydroepiandrosterone sulfate levels as the reproductive phenotype in the brothers of women with polycystic ovary syndrome.

There is an inherited susceptibility to polycystic ovary syndrome (PCOS). Some investigators have suggested that premature male-pattern balding is a male phenotype in PCOS families, but this remains controversial. We recently reported evidence for an autosomal monogenic abnormality in ovarian and adrenal steroidogenesis in the sisters of women with PCOS. We performed this study to determine whether we could identify a clinical or biochemical phenotype in the brothers of women with PCOS. One hundred nineteen brothers of 87 unrelated women with PCOS and 68 weight- and ethnicity-comparable unrelated control men were examined and had fasting blood samples obtained. The odds of balding (Hamilton score > or = V) did not differ in the brothers of PCOS women compared with control men. Brothers of women with PCOS had significantly elevated dehydroepiandrosterone sulfate (DHEAS) levels [brothers 3035 +/- 1132 ng/ml (mean +/- SD) vs. control men 2494 +/- 1172 ng/ml; P < 0.05]. There was a significant positive linear relationship between DHEAS levels in PCOS probands and their brothers (r = 0.35; P = 0.001). There was no significant bimodal distribution in DHEAS levels, and there were no significant differences in other parameters in brothers of PCOS women with high DHEAS levels compared with those with low DHEAS levels. There is familial clustering of elevated DHEAS levels in the brothers of women with PCOS, suggesting that this is a genetic trait. This might reflect the same underlying defect in steroidogenesis that we found in the sisters of women with PCOS. Balding was not increased in the brothers of women with PCOS. We conclude that there is a biochemical reproductive endocrine phenotype in men in PCOS families.

Adult↗
PubMedDate not supplied

Precise quantification of pressure flow waveforms of a pulsatile ventricular assist device.

Unreliable quantification of flow pulsatility has hampered many efforts to assess the importance of pulsatile perfusion. Generation of pulsatile flow depends upon an energy gradient. It is necessary to quantify pressure flow waveforms in terms of hemodynamic energy levels to make a valid comparison between perfusion modes during chronic support. The objective of this study was to quantify pressure flow waveforms in terms of energy equivalent pressure (EEP) and surplus hemodynamic energy (SHE) levels in an adult mock loop using a pulsatile ventricle assist system (VAD). A 70 cc Pierce-Donachy pneumatic pulsatile VAD was used with a Penn State adult mock loop. The pump flow rate was kept constant at 5 L/min with pump rates of 70 and 80 bpm and mean aortic pressures (MAP) of 80, 90, and 100 mm Hg, respectively. Pump flows were adjusted by varying the systolic pressure, systolic duration, and the diastolic vacuum of the pneumatic drive unit. The aortic pressure was adjusted by varying the systemic resistance of the mock loop EEP (mm Hg) = (integral of fpdf)/(integral of fdt) SHE (ergs/cm3) = 1,332 [((integral of fpdt)/(integral of fdt))--MAP] were calculated at each experimental stage. The difference between the EEP and the MAP is the extra energy generated by this device. This difference is approximately 10% in a normal human heart. The EEP levels were 88.3 +/- 0.9 mm Hg, 98.1 +/- 1.3 mm Hg, and 107.4 +/- 1.0 mm Hg with a pump rate of 70 bpm and an aortic pressure of 80 mm Hg, 90 mm Hg, and 100 mm Hg, respectively. Surplus hemodynamic energy in terms of ergs/cm3 was 11,039 +/- 1,236 ergs/cm3, 10,839 +/- 1,659 ergs/cm3, and 9,857 +/- 1,289 ergs/cm3, respectively. The percentage change from the mean aortic pressure to EEP was 10.4 +/- 1.2%, 9.0 +/- 1.4%, and 7.4 +/- 1.0% at the same experimental stages. Similar results were obtained when the pump rate was changed from 70 bpm to 80 bpm. The EEP and SHE formulas are adequate to quantify different levels of pulsatility for direct and meaningful comparisons. This particular pulsatile VAD system produces near physiologic hemodynamic energy levels at each experimental stage.

Adult↗