Early Hemodynamic Effects Research Articles

Early Hemodynamic Effects of Mydriatic Eye Drops in Preterm Infants.

Mydriatic eye drops used for retinopathy of prematurity (ROP) examination can cause systemic effects, and there are case reports of serious adverse effects in the literature. In this prospective study, we aimed to evaluate the early hemodynamic effects of mydriatic eye drops to understand the possible mechanisms of adverse effects. Between December 2018 and March 2019, preterm babies less than 32 gestational weeks and who underwent ophthalmologic examination in our unit were included. The vital signs (heart rate, respiratory rate, oxygen saturation [SpO2], and blood pressure values), cerebral and mesenteric tissue saturation by near-infrared spectroscopy (NIRS), and left ventricular functions of infants were recorded before and after applying mydriatic eye drops (2.5% phenylephrine and 0.5% tropicamide). The data were compared statistically. Strict adherence to prevent systemic absorption of the eye drops was applied. Thirty-two mydriasis procedures were evaluated in 26 patients. The mean gestational age was 28.5 ± 1.7 weeks, and the mean birth weight was 943 ± 233 g. There were no significant differences in terms of vital signs of infants including heart rate, blood pressure, and oxygen saturation [SpO2] levels before and after eye-drop application. In addition, NIRS values showed no significant differences between before and after measurements. No significant differences were detected at echocardiographic evaluation performed before and after mydriatic administration. No adverse reaction was observed in the study population during the study. This is the first study that evaluated the early hemodynamic effects of mydriatic eye drops used for ROP screening by vital signs, NIRS, and echocardiographic evaluation. Mydriatic eye drops have no significant effect on early hemodynamic parameters including vital signs, NIRS, and echocardiographic findings in preterm infants. We suggest that a cautious approach for avoiding the systemic absorption of these agents may prevent the possible early systemic effects in this high-risk population. · Mydriatic eye drops are commonly used for pupil dilatation before retinopathy of prematurity examination, and there are reports of serious adverse events caused by these drops.. · Due to the adverse events of eye drops, hemodynamic effects of these agents were investigated by clinical findings, near-infrared spectroscopy, and echocardiography.. · No significant early hemodynamic effect was observed so avoiding systemic effects may be prevented with precautions..

A comparison of the hemodynamic effects of fluid bolus therapy with crystalloids vs. 4% albumin and vs. 20% albumin in patients after cardiac surgery

Background: Crystalloids, 4% albumin and 20% albumin are used for fluid bolus therapy (FBT) in patients after cardiac surgery. However, their detailed early (30 min) hemodynamic effects remain unstudied.Methods: In a comparative prospective observational trial of 120 ventilated, we studied post cardiac surgery patients who received crystalloid 500 ml FBT, 4% albumin 500 ml FBT or 20% albumin 100 ml FBT (40 per group). We recorded second-by-second hemodynamic parameters and 15-minutely cardiac index (CI) data before and for 30 min after FBT. We compared the crystalloid group (reference) vs. the 4% albumin group, and vs. the 20% albumin group.Results: Immediately after FBT, the mean (standard deviation) CI increase was 0.4 (0.4) L/min/m2 with crystalloids, 0.4 (0.5) L/min/m2 with 4% albumin and 0.3 (0.4) L/min/m2 with 20% albumin, despite the much smaller FBT volume with 20% albumin. Mean arterial pressure (MAP) increase was 11 (10), 12 (9) and 9 (6) mm Hg, respectively. There was no group effect or interaction for changes in CI. However, there were time-group interactions for MAP changes such that crystalloid FBT had faster MAP reduction than 4% (p<0.001) or 20% albumin (p < 0.001). Moreover, patients treated with crystalloid FBT showed a faster decline in central venous pressure, perfusion pressure than the two groups. Finally, 20% albumin attenuated the fall in temperature induced by FBT.Conclusion: In postoperative cardiac surgery patients, after a similar initial CI and MAP response, the MAP effect of crystalloid FBT dissipates faster than that of 4% or 20% albumin FBT. These findings can be used to inform clinical practice.

Early Hemodynamic Effects of Transcatheter Tricuspid Valve Repair - Insights from Cardiac Magnetic Resonance

Early Hemodynamic Effects of Transcatheter Tricuspid Valve Repair - Insights from Cardiac Magnetic Resonance

Early hemodynamic effects after extended liver radiofrequency ablation

BackgroundThe purpose of the present study was to assess early intestinal and systemic hemodynamic effects after extended radiofrequency ablation (RFA) of the liver in terms of investigating their potential contribution to gut barrier disruption. Materials and methodsTen rabbits were assigned to two groups of five animals each and were subjected to either 30% liver RFA (group RFA-1) or sham operation (group sham-1). Blood flow rate at the superior mesenteric artery (SMA) was monitored for 90 min after operation. Ileal tissue was excised at 48 h for histomorphometric and histopathologic analysis. Eight pigs were assigned to two groups of four animals each and were also subjected to either 30% liver RFA (group RFA-2) or sham operation (group sham-2). A panel of systemic hemodynamic parameters was serially measured up to 90 min after operation. ResultsIn group RFA-1, SMA blood flow rate was lower than that in group sham-1 throughout the study period. Intestinal mucosa atrophy and a deterioration of histopathologic profile were noted in group RFA-1. In group RFA-2, diastolic pulmonary artery pressure was lower (60–90 min), central venous pressure was gradually decreased, arterial pressure was higher (30–90 min), and systemic vascular resistance was higher (30–90 min) than those in group sham-2. No change was noted in the cardiac output. ConclusionsIn conclusion, SMA blood flow was reduced during the early post-RFA period, justifying an ischemic insult at the intestine. In addition, a gradual decrease of the preload was counterbalanced by an increase of systemic vascular resistance leaving the cardiac output unaffected.

Haemodynamic and renal effects of resuscitation of dogs from haemorrhagic shock with hypertonic saline or Lactated Ringer's solution combined with whole blood

Despite numerous studies on haemorrhagic shock treatment, the choice of fluid and the rate of administration is a subject of controversy. Early haemodynamic effects, neuroendocrine response and renal function following acute sodium load with either hypertonic saline (HS) or Lactated Ringer's (LRS) were investigated in a model of controlled haemorrhagic shock. Six anaesthetized dogs were bled 30% of calculated blood volume, i.e., 27 ml/kg b.w. over 15 min and left untreated for 30 min. Afterward, the dogs were treated with either HS 4 ml/kg b.w. or LRS 81 ml/kg b.w., followed by whole blood. After a resting period of at least 30 days, the dogs underwent a similar second shock experiment, but with the second solution. Haemodynamics, renal effects and neuroendocrine response were studied during shock and at 15, 30, 45 and 60 min after administration of HS or LRS and 30 and 60 min after the addition of whole blood. LRS treatment resulted in significantly higher cardiac filling pressures and cardiac performance indexes than HS but, following whole blood administration, there were no differences between treatments, except that pulmonary capillary wedge pressure was higher in the LRS group. Urinary output and glomerular filtration rate index were restored to normal values by both treatments; however, they were significantly higher in the LRS group until whole blood was administered. LRS and HS restored plasma norepinephrine to baseline values with no difference between the treatments. Both solutions improved haemodynamics and renal function but their effects were short lived and whole blood was required for a favourable outcome, regardless of the initial solution used. In contrast to LRS, HS did not overload the cardiovascular system.

Hemodynamic effects of early endotoxemia on pulse pressure variation during experimental hemorrhagic shock

Although pulse pressure variation (PPV) is essentially proposed as a predictor of fluid responsiveness [1], it has also been appointed as an early detector of hypovolemia [2]. Still, caution has been recommended for its employment in certain conditions, as during pulmonary hypertension (PH) [2,3]. Endotoxin-induced PH produces biphasic increase in mean pulmonary artery pressure (MPAP) in several animal models, in which the early phase is acute and transient [4]. The objective of this study was to analyze the early hemodynamic effects of endotoxemia on PPV, during severe hypovolemic shock.

Cerebral watershed hypoperfusion in subarachnoid hemorrhage: computed tomography perfusion analysis

A better understanding of the pathophysiology of vasospasm-induced delayed cerebral ischemia and earlier detection of hypoperfusion before ischemic injury are needed to guide therapy in subarachnoid hemorrhage (SAH). The cerebrovascular physiology of the major arterial territories differs from that of the watershed zones (WZs) in a way that would suggest a differential topographic sensitivity of the brain to vasospasm. The primary end point of the study was to investigate the vasospasm-induced hypoperfusion in relation to cerebrovascular topography and timing from the onset of SAH. Forty-one patients were prospectively enrolled and scheduled for perfusion-weighted (PW) CT at 3 time points (≤ 3 days, Days 4-8, and Days 9-15 after SAH). Perfusion-weighted CT maps were visually assessed for side-to-side perfusion asymmetry. The PW CT topographic pattern was categorized into absence of asymmetry, WZ, and vascular territory hypoperfusion. Perfusion-weighted CT revision was performed by investigators blinded to clinical information. The null hypothesis for the primary end point was that there would be no difference in hypoperfusion space-time distribution among the different vascular territories. Multivariate logistic regression and Cox proportional hazards modeling were used for statistical analysis. Delayed cerebral ischemia occurred in 26 patients and its predicting variables were increasing age (p = 0.045), Fisher grade (p = 0.007), and hypoperfusion on the PW CT performed within the 1st 72 hours after SAH (p = 0.004). The timing of the PW CT with respect to the day of SAH affected the topographic pattern of hypoperfusion: watershed-zone hypoperfusion was more common within the first 3 days after SAH (p = 0.018), while the proportion of territorial hypoperfusion increased subsequently. Among the different covariates, a young age was independently associated with a higher risk of developing hypoperfusion in the WZs (p = 0.02). This study suggests the existence of a cerebral topographic heterogeneity to the hemodynamic effects of SAH and differential pathogenetic mechanisms of hypoperfusion according to timing, age, and brain topography. Hypoperfusion in the WZs may be an early precursor to more profound ischemic events. The PW CT detection of such brain-sensitive zones could offer a warning signal of the early hemodynamic effects of SAH and cerebral vasospasm.

Letter by Deutsch and Kaczmarek Regarding Article, “Donor Pretreatment With Hypertonic Saline Attenuates Primary Allograft Dysfunction: A Pilot Study in a Porcine Model”

To the Editor: We read with great interest the article by Badiwala et al1 describing donor pretreatment with hypertonic saline as being effective in attenuating primary allograft dysfunction in an experimental porcine heart transplant model. The positive influence of hypertonic saline on enhanced ventricular recovery after storage-related ischemia-reperfusion injury and subsequent transplantation was ascribed to an improvement of early hemodynamics and beneficial immunomodulatory and vasculomodulatory effects.1 A work published by Harada and associates2 might explain the early positive hemodynamic effects. Postischemic dysfunction after short-term global ischemia in isolated blood-perfused dog hearts was caused by a decreased responsiveness of the contractile elements to intracellular …

Early and Sustained Systemic and Renal Hemodynamic Effects of Intravenous Radiocontrast

Background and Aims: To measure the extended renal hemodynamic changes induced by intravenous radiocontrast. Methods: Cross-ewes were studied in a randomized cross-over study. Intravenous saline or radiocontrast were administered, and continuous measurement of cardiac output and renal blood flow (RBF) was performed with flow probes. Results: Radiocontrast induced early but transient increases in cardiac output with vasodilatation, followed by return to baseline values within 2 h. There was an initial decline in RBF (–5.2 ± 4.5 vs. 2.1 ± 5.3%; p < 0.0001) and decreased renal vascular conductance (–4.0 ± 7.2 vs. 3.3 ± 7.1%, p < 0.0001; vasoconstriction). This renal vasoconstriction resolved within 2 h and was followed by sustained (72 h) renal vasodilatation with higher RBF (270 ± 13 vs. 236 ± 11 ml/min; p < 0.0001). Conclusions: Radiocontrast induces short renal vasoconstriction followed by sustained vasodilatation and increased RBF. Short-term studies are not representative of the overall sustained renal hemodynamic effects of radiocontrast.

Early Hemodynamic and Renal Effects of Hemorrhagic Shock Resuscitation with Lactated Ringer’s Solution, Hydroxyethyl Starch, and Hypertonic Saline with or without 6% Dextran-70

Considering the renal effects of fluid resuscitation in hemorrhaged patients, the choice of fluid has been a source of controversy. In a model of hemorrhagic shock, we studied the early hemodynamic and renal effects of fluid resuscitation with lactated Ringer's (LR), 6% hydroxyethyl starch (HES), and 7.5% hypertonic saline (HS) with or without 6% dextran-70 (HSD). Forty-eight dogs were anesthetized and submitted to splenectomy. An estimated 40% blood volume was removed to maintain mean arterial pressure (MAP) at 40 mm Hg for 30 min. The dogs were divided into four groups: LR, in a 3:1 ratio to removed blood volume; HS, 6 mL kg(-1); HSD, 6 mL kg(-1); and HES in a 1:1 ratio to removed blood volume. Hemodynamics and renal function were studied during shock and 5, 60, and 120 min after fluid replacement. Shock treatment increased MAP similarly in all groups. At 5 min, cardiac filling pressures and cardiac performance indexes were higher for LR and HES but, after 120 min, there were no differences among groups. Renal blood flow and glomerular filtration rate (GFR) were higher in LR at 60 min but GFR returned to baseline values in all groups at 120 min. Diuresis was higher for LR at 5 min and for LR and HES at 60 min. There were no differences among groups in renal variables 120 min after treatment. Despite the immediate differences in hemodynamic responses, the low-volume resuscitation fluids, HS and HSD, are equally effective to LR and HES in restoring renal performance 120 min after hemorrhagic shock treatment.

Effects of graded-release diltiazem versus ramipril, dosed at bedtime, on early morning blood pressure, heart rate, and the rate-pressure product

Background Therapeutic agents for the treatment of hypertension may differ in their efficacy during the early morning period, a time when both morbid and mortal cardiovascular events are increased compared to other times of the day. Methods We studied the effects of a graded-release delivery system of diltiazem (diltiazem HCL extended release tablets) versus ramipril, both dosed at bedtime, on blood pressure (BP), heart rate, and the heart rate-systolic BP product during the first 4 hours after awakening in a double-blind, titration-to-effect trial. There were 261 men and women enrolled in the trial with an untreated sitting diastolic BP of 90 to 109 mm Hg and ambulatory daytime diastolic BP of 85 to 109 mm Hg. Patients were randomized to either diltiazem extended release (ER) tablets each evening (240 mg titrated to 360 mg and to 540 mg) or ramipril each evening (5 mg titrated to 10 mg and to 20 mg). Early morning assessments of BP, heart rate, and the heart rate-systolic BP product were performed using 24-hour ambulatory recordings after 10 weeks of therapy. Results In each therapeutic group, 76% of patients were titrated to the highest possible dose. After 10 weeks of treatment, reductions in early morning BP by diltiazem ER tablets were significantly greater (−18/−15 mm Hg) than reductions by ramipril (−13/−8 mmHg , P < .005 for systolic BP and P < .001 for diastolic BP). Diltiazem ER tablets also led to greater reductions in morning heart rate and the heart rate-pressure product compared to ramipril. Reductions in mean 24-hour diastolic BP, heart rate, and the rate-pressure product were greater in patients treated with diltiazem ER tablets compared to ramipril, while reductions in 24-hour systolic BP were similar in each group. The observed adverse effects were not serious and incidences were similar for the 2 treatment groups. Conclusions These data demonstrate that bedtime administration of diltiazem ER, an agent designed to parallel the circadian rhythm of BP and heart rate, led to significantly greater early morning hemodynamic effects compared to the angiotensin-converting enzyme inhibitor ramipril, also dosed in the evening.

Preventing increases in early-morning blood pressure, heart rate, and the rate-pressure product with controlled onset extended release verapamil at bedtime versus enalapril, losartan, and placebo on arising

Background Therapeutic agents for the treatment of hypertension may differ in their efficacy during the early-morning period, a time when both morbid and mortal cardiovascular events are increased compared with other times of the day. Methods We studied the effects of a chronotherapeutic delivery system of verapamil (controlled-onset extended release [COER]-24 system) dosed at bedtime versus conventional morning administration of both enalapril and losartan on the blood pressure (BP), heart rate, and the heart rate systolic BP product during the first 4 hours after awakening in a placebo-controlled, forced-titration trial. There were 357 men and women enrolled in the trial with an untreated sitting diastolic BP of 95 to 114 mm Hg and ambulatory daytime diastolic BP ≥85 mm Hg. Patients were randomized to either COER-verapamil hydrochloride each evening (240 mg titrated to 360 mg), enalapril each morning (10 mg titrated to 20 mg), losartan each morning (50 mg titrated to 100 mg), or placebo. Early morning assessments of BP, heart rate, and the heart rate systolic BP product were performed by use of 24-hour ambulatory recordings after 4 weeks (low dose) and 8 weeks (high dose) of therapy. Results Results were similar at weeks 4 and 8 for all treatment groups except that the magnitude of change was greater at week 8. After 8 weeks of treatment, reductions in early morning BP by COER-verapamil were significantly greater (−15/−10 mm Hg) than enalapril (−9/−7 mm Hg, P <.01) and losartan (−8/−5 mm Hg, P <.001). COER-verapamil also led to greater reductions in morning heart rate, the rate-pressure product, and the rate-of-rise of BP compared with the other 2 active treatment groups. Reductions in mean 24-hour BP were greater in patients treated with COER-verapamil compared with placebo and losartan, and similar to reductions in patients treated with enalapril. Conclusions Bedtime administration of an agent designed to parallel the circadian rhythm of BP and heart rate led to significantly greater early morning hemodynamic effects compared with other conventional once-daily antihypertensive agents dosed in the morning. (Am Heart J 2002;144:657-65.)

Recovery of Erectile Function after Brief Aggressive Antihypertensive Therapy

We have previously demonstrated that antihypertensive therapy could structurally modulate blood vessels in the penis, although the impact on erectile function was not established. Given the importance of inadequate penile arterial inflow as a cause of erectile dysfunction we determined in spontaneously hypertensive rats the impact of brief aggressive antihypertensive therapy on structurally based penile vascular resistance, erectile function and mean arterial pressure during and after treatment. Young (15-week-old) and aged (40-week-old) spontaneously hypertensive rats were treated for 2 weeks (enalapril 30 mg./kg. daily plus a low salt diet). Mean arterial pressure was continuously monitored via radio telemetry. Erectile responses were assessed by administering apomorphine (80 microg./kg. subcutaneously) before, during and after treatment. Structurally based vascular resistance was determined in the isolated, perfused penile vasculature 2 weeks after stopping treatment in aged spontaneously hypertensive rats. Certain responses were determined, including resistance at maximum dilatation (lumen size) and at maximum constriction (medial bulk), and EC50 of the alpha-adrenoceptor agonist methoxamine. In the period after the cessation of drug treatment there was a persistent reduction in the level of arterial pressure (16%) and a doubling of erectile responses compared with pre- treatment. Cardiac and vascular structure regressed, as determined by the mean decrease plus or minus standard deviation in vascular resistance at maximum dilatation (21% +/- 4.5%) and mean reduction in left ventricle mass (10.4% +/- 3.7%). Furthermore, treatment induced a significant right shift in alpha1-adrenoceptor concentration response curve in treated versus control rats (mean EC50 1.09 +/- 0.111 versus 0.76 +/- 0.111). The improvement in erectile function after brief aggressive treatment may be related to improvement in structurally based vascular resistance within the penis and the decrease in responsiveness of alpha1-adrenoceptor mediated erectolytic signaling. These findings are suggestive of a new therapeutic strategy for hypertension and erectile dysfunction.

Impact of cardiac resynchronization therapy using hemodynamically optimized pacing on left ventricular remodeling in patients with congestive heart failure and ventricular conduction disturbances

ObjectivesWe sought to investigate the impact of six months of cardiac resynchronization therapy (CRT) on echocardiographic variables of left ventricular (LV) function. BackgroundCardiac resynchronization therapy has recently been introduced as a new therapeutic modality in patients with advanced heart failure (HF) and conduction abnormalities. However, most studies have only investigated the early hemodynamic effects of CRT. MethodsTwenty-five patients (12 women and 13 men; 59.8 ± 5.1 years old) with advanced HF caused by ischemic (n = 7) or idiopathic dilated cardiomyopathy (n = 18) and a prolonged QRS complex were analyzed. All patients underwent early hemodynamic testing with a randomized testing protocol; echocardiographic measurements were compared before implantation and after six months of CRT. ResultsLeft ventricular end-diastolic and end-systolic diameters (LVEDD and LVESD, respectively) were significantly reduced after six months (LVEDD from 71 ± 10 to 68 ± 11 mm, p = 0.027; LVESD from 63 ± 11 to 58 ± 11 mm, p = 0.007), as were LV end-diastolic and end-systolic volumes (LVEDV from 253 ± 83 to 227 ± 112 ml, p = 0.017; LVESV from 202 ± 79 to 174 ± 101 ml, p = 0.009). Ejection fraction was significantly increased (from 22 ± 7% to 26 ± 9%, p = 0.03). “Nonresponders,” with regard to LV volume reduction, had significantly higher baseline LVEDV, compared with “responders” (351 ± 52 vs. 234 ± 74 ml, p = 0.018). Overall, there was only mild mitral regurgitation at baseline, with a minor reduction by semiquantitative analysis. The results of early hemodynamic testing did not predict the volume response. ConclusionsCardiac resynchronization therapy may lead to a reduction in LV volumes in patients with advanced HF and conduction disturbances. Volume nonresponders have significantly higher baseline LVEDV.

Dose-dependent biphasic effect of ethanol on 24-h blood pressure in normotensive subjects

The vasodilation that follows acute alcohol intake is hard to conciliate with the high prevalence of hypertension detected in those persons who consume regular amounts of alcohol. In this experiment we examined early and late hemodynamic effects of acute administration of water and of 15 g, 30 g, and 60 g of alcohol in 40 normal men, aged 19 to 30 years, using 24-h ambulatory blood pressure monitoring (ABPM). Mean systolic and diastolic blood pressures were each approximately 4 mm Hg lower during the period immediately after ingestion of 60 g ( v 0 g) of ethanol, and were 7 and 4 mm Hg higher, respectively, at night. The day minus night differences displayed a dose-response curve both for systolic ( P < .001) and diastolic blood pressure ( P = .045). Three subjects in the 60-g group had more than 50% of nightly blood pressure loads in the hypertensive range against none in the remaining groups ( P < .01). In conclusion, our findings suggest that acute alcohol intake elicits a biphasic hemodynamic response, causing, first, vasodilatation and, later, a pressor effect. The higher prevalence of hypertension in alcohol abusers seen in epidemiological surveys may be, in part, a result of measurements done in the period of transiently increased blood pressure during ethanol washout.

Early Hemodynamic Effects of Percutaneous Transluminal Angioplasty in Superficial Femoral Artery Disease

This study was conducted to assess the early hemodynamic effects of percutaneous trans luminal angioplasty (PTA) in patients with superficial femoral artery (SFA) atheroscle rotic disease. Seventeen patients (forty-nine to eighty-five years, median sixty-seven years), underwent PTA in the SFA, except 1 who had PTA in both the SFA and popliteal artery. Fifteen patients were claudicant whereas the other one had rest pain and ulcera tion. Ten patients had localized SFA occlusion on the angiogram (3 of them had combined stenoses in the common femoral, profunda, and popliteal arteries) and 7 had localized stenoses more than 50%. Ankle-brachial index (ABI), limb blood flow (measured by air plethysmography), peak systolic velocity (PSV) ratio across the stenosis, and the spectral waveform analysis displayed by color flow duplex imaging (CFDI) were assessed before and one day after PTA. Before PTA, the median ABI and limb blood flow were 0.55 ±0.19 and 58.6 ±13.1 mL/min, respectively. The waveform in the poststenotic area of the SFA was monophasic in 5 patients and biphasic in the others, and the PSV was at least doubled in the stenotic area. PTA was technically successful in 16 patients and failed in 1 with an occluded SFA. After successful PTA the median ABI was 0.76 ±0.15 (P&lt;0.00001), and the median limb blood flow was 78.1 ±11.9 mL/min (P&lt;0.00001). The waveform in the dilated area of the SFA was biphasic in all patients with marked decrease in the PSV and forward diastolic velocity present. Postangioplasty pain-free walking distance was at least doubled in 12 patients. In the case of the failed PTA the ABI, limb blood flow, poststenotic waveform, PSV, and pain-free walking-distance were unchanged. In conclusion, early improvement in the hemodynamic parameters occurs over the first day after a successful PTA. These hemodynamic parameters correlate well with the findings of the postangioplasty angiogram and thus can be used in the follow-up of the patients after PTA.

Early Hemodynamic Effects of Left Atrial Administration of Epinephrine After Cardiac Transplantation

We studied the hemodynamic effects of left atrial (LA) administration of epinephrine in 10 patients after cardiac transplantation, using a prospective, randomized, double-blind, cross-over design. After allograft implantation, a LA catheter was inserted and epinephrine infusion commenced at 100 ng [centered dot] kg-1 [centered dot] min-1. Each trial period consisted of 20 min, with the LA and right atrial (RA) lines switched over between each period; hemodynamic measurements were taken after each time period. Whether epinephrine was administered via the RA or LA did not significantly alter hemodynamics (RA versus LA): mean (SD) arterial blood pressure 67 (7.5) vs 64 (9.5) mm Hg (P = 0.16), mean pulmonary artery pressure 22 (4.0) vs 21 (9.4) mm Hg (P = 0.67), cardiac index 3.2 (1.1) vs 3.2 (1.1) L [centered dot] min-1 [centered dot] m-2 (P = 0.83), pulmonary vascular resistance index 308 (157) vs 345 (157) dynes [centered dot] s [centered dot] cm-5/m-2 (P = 0.30) or right ventricular ejection fraction 35% (11%) vs 32% (9.8%) (P = 0.23). Arterial epinephrine plasma levels were similar (P = 0.16). There was no significant pulmonary extraction of measured catecholamines. We observed no hemodynamic benefit of LA epinephrine administration. It may be that the cardiac transplantation population reacts differently compared with other cardiac surgical patients (possibly because pulmonary extraction of catecholamines is reduced). Because we did not observe a hemodynamic advantage in patients immediately after cardiac transplantation, we would not recommend the use of LA epinephrine at the dose studied. (Anesth Analg 1997;84:976-81)

Influence of indomethacin on the haemodynamic effects of lipopolysaccharide in rats.

This study was undertaken to evaluate the influence of the cyclooxygenase inhibitor indomethacin on the time course of the haemodynamic effects of lipopolysaccharide (LPS) intravenous infusion (10 mg.kg-1.h-1) in anaesthetized rats. LPS infusion produced a rapid (within 10 min) and prolonged (over the 90 min observation period) fall in mean arterial blood pressure (MABP) and a decrease in the pressor responses to noradrenaline (NA, 0.1, 0.3 and 1 microgram.kg-1, intravenously [i.v.]) elicited 60 and 90 min after the onset of LPS infusion. Indomethacin (7 mg.kg-1 i.v. 30 min prior to the onset of saline or LPS infusion), which by itself did not affect basal MABP nor reactivity to NA in control rats, significantly attenuated the fall in MABP observed within 20 min after the onset of LPS infusion (but did not significantly modify the hypotension observed between 30 and 90 min). Indomethacin also completely prevented the hyporeactivity to NA observed 60 min after the onset of LPS infusion, but it did so only partially at 90 min. Aortic rings removed from LPS or LPS + indomethacin-treated rats showed an identical profile of contractile reactivity (hyporesponsiveness to NA, relaxation to L-arginine, and restoration of the contractile response by methylene blue). These results suggest that in this model, cyclooxygenase products are involved in the early haemodynamic effects of LPS. However, they do not seem to play an obligatory role in the onset of longer term haemodynamic changes.

Haemodynamic effects of arteriovenous and venovenous haemofiltration in piglets.

The aim of this study was to compare the early haemodynamic effects of continuous arteriovenous haemofiltration (CAVH) with those of continuous venovenous haemofiltration (CVVH) in normal and endotoxic piglets, within the framework of a two-period cross-over trial. Sixteen domestic piglets (weight 6-18 kg) underwent 1 h of CAVH followed by 1 h of CVVH or 1 h of CVVH followed by 1 h of CAVH. Six were pre-treated with a graded endotoxin infusion to simulate clinical sepsis. The main measurements included: heart rate; mean arterial (MAP), pulmonary artery, central venous and pulmonary artery occlusion pressures; thermodilution cardiac output; and calculated systemic (SVRI) and pulmonary vascular resistance indexes. Each measurement was performed immediately before and 30 min after commencement of each technique of filtration. Commencement of haemofiltration in normal piglets caused minimal haemodynamic effects. In endotoxic piglets, commencement of filtration, whether CAVH or CVVH, caused a haemodynamic change which was significantly more pronounced in the first filter (SVRI -39%, MAP -32%) than the second filter (SVRI +22%, MAP +0.9%) (SVRI, P=0.01, first filter vs. second) (MAP, P=0.009 first filter vs. second). In conclusion, there were no significant differences between the early haemodynamic effects of CAVH and CVVH in normal or endotoxic piglets. The haemodynamic effects of either technique may become more significant in the presence of sepsis.

Early hemodynamic effects at rest with acute and chronic isosorbide dinitrate treatment in patients with ischemic heart disease

Asymmetric dosage regimens are used to circumvent development of nitrate tolerance and are believed to restore totally the hemodynamic responsiveness to an acute dosage of nitrates. This study assessed invasively the hemodynamics during supine rest before and for 50 min after peroral 30 mg isosorbide dinitrate (ISDN) in 16 patients with stable ischemic heart disease; 8 previously untreated patients (NT group) and 8 patients treated asymmetrically b.i.d. with 30 mg ISDN for 14 days prior to the invasive investigation (T group). Before initiation of treatment, both groups had identical mean arterial pressure (MAP) and heart rate (HR). On the day of invasive investigation, before intake of ISDN, MAP was higher in the T group but unchanged in the NT group. After the intake of ISDN, right atrial pressure (RAP), mean pulmonary arterial pressure, and pulmonary arterial wedge pressure declined markedly within 10 to 15 min in both groups, while MAP showed a more protracted decline, reaching a new level only after 25 to 30 min. In the NT group, HR accelerated markedly and remained elevated throughout the observation period, whereas in the T group HR showed no significant alteration after ISDN intake. At the end of the observation period, the cardiac index (CI) was definitely reduced in the NT group, but remained unchanged in the T group, while the systemic vascular resistance index was unchanged in the former and was clearly reduced in the latter. It is concluded that the fall in MAP in the NT group was solely due to a fall in CI, and that the decline in RAP and venous return in the NT group induced neurohumoral reflexes leading to a rise in HR and prevention of arterial dilation, whereas in the T group, already influenced by chronic treatment, such acute counterregulatory responses were markedly attenuated or absent.