[BRONCHOPULMONARY DYSPLASIA--WHAT DO WE KNOW TODAY?]

The survival of great number of extremely premature newborn babies is associated with increased risk of damage of the newborn lung and development of chronic lung disease/Broncopulmonary dysplasia. The lower the gestational age and weight, the greater the frequency of BPD. The disease leads to impairment of the normal alveolization and vascularization of the premature lung. There are new theories for the pathogenesis of BPD and new staging of the disease. These changes lead to new therapeutic strategies.

Milrinone ameliorates cardiac mechanical dysfunction after hypothermia in an intact rat model

BACKGROUND

Rewarming from hypothermia is often complicated by cardiac dysfunction, characterized by substantial reduction in stroke volume. Previously we have reported that inotropic agents, working via cardiac β-receptor agonism may exert serious side effects when applied to treat cardiac contractile dysfunction during rewarming. In this study we tested whether Milrinone, a phosphodiesterase III inhibitor, is able to ameliorate such dysfunction when given during rewarming.

METHODS

A rat model designed for circulatory studies during experimental hypothermia with cooling to a core temperature of 15°C, stable hypothermia at this temperature for 3h and subsequent rewarming was used, with a total of 3 groups: (1) a normothermic group receiving Milrinone, (2) a hypothermic group receiving Milrinone the last hour of hypothermia and during rewarming, and (3) a hypothermic saline control group. Hemodynamic function was monitored using a conductance catheter introduced to the left ventricle.

RESULTS

After rewarming from 15°C, stroke volume and cardiac output returned to within baseline values in Milrinone treated animals, while these variables were significantly reduced in saline controls.

CONCLUSIONS

Milrinone ameliorated cardiac dysfunction during rewarming from 15°C. The present results suggest that at low core temperatures and during rewarming from such temperatures, pharmacologic efforts to support cardiovascular function is better achieved by substances preventing cyclic AMP breakdown rather than increasing its formation via β-receptor stimulation.

The effect of milrinone on induced hypotension in elderly patients during spinal surgery: a randomized controlled trial

BACKGROUND CONTEXT

Induced hypotension is widely used intraoperatively to reduce blood loss and to improve the surgical field during spinal surgery.

PURPOSE

To determine the effect of milrinone on induced hypotension during spinal surgery in elderly patients.

STUDY DESIGN/SETTING

Prospective randomized clinical trial.

PATIENT SAMPLE

Forty patients, 60 to 70 years old, ASA I-II, who underwent elective lumbar fusion surgery.

OUTCOME MEASURES

Intraoperative hemodynamics, blood loss, hourly urine output, and grade of surgical field.

METHODS

All patients were randomized to group M or N. The study drug was infused after perivertebral muscle retraction until complete interbody fusion. In group M, 50 μg/kg/min of milrinone was infused over 10 minutes as a loading dose followed by 0.6 μg/kg/min of milrinone as a continuous dose. In group N, an identical volume of normal saline was infused in the same fashion. This study was not funded by commercial or other sponsorship and the authors confirm no conflicts of interest, financial or otherwise.

RESULTS

During infusion of the study drug, the systolic and mean blood pressures were maintained within adequate limits of induced hypotension in group M. Intraoperative blood loss was 445.0±226.5 mL in group M and 765.0±339.2 mL in group N (p=.001). Hourly urine output was 1.4±0.6 mL in group M and 0.8±0.2 mL in group N (p<.001). The grade of the surgical field was better in group M than in group N (p=.004).

CONCLUSIONS

We conclude that milrinone is useful for induced hypotension in elderly patients during spinal surgery.

A neonate with critical congenital heart disease

Critical congenital heart disease (CCHD) is defined as a ductal-dependent congenital heart defect requiring surgical or percutaneous intervention via cardiac catheterization before 1 year of age. Most cases of CCHD can be diagnosed with prenatal ultrasound or fetal echocardiogram. If not prenatally diagnosed, CCHD can be stable in the newborn nursery due to persistent ductal patency, and the patient may only be diagnosed after ductal closure and development of cardiac symptoms at home. In this case, a 6-day-old female presented to the emergency department (ED) floppy with agonal respirations, poor capillary refill, and absent femoral pulses. On the day of presentation, the patient became increasingly fussy, refused feeding, and began to gasp. The patient was transported to the ED for evaluation, where a bedside echocardiogram revealed interrupted aortic arch (IAA), ventricular septal defect, minimal flow through a thread-like ductus arteriosus, and severely depressed cardiac function. IAA is very rare, with an incidence of three cases per 1 million live births. Patients require neonatal supportive care, continuous prostaglandin E1 infusion, and urgent referral for neonatal surgical repair in the first days to weeks of life. To reduce the volume of undiagnosed CCHD in the immediate newborn period, the U.S. Department of Health and Human Services Secretary's Advisory Committee on Heritable Diseases in Newborns and Children (SACHDNC) recommended that CCHD screening via pulse oximetry be added to the recommended uniform screening panel. A positive screen results in an immediate referral for an echocardiogram. Fetal diagnosis, newborn screening, and/or careful clinical examination may have resulted in detection of IAA in our patient prior to ductal closure.

Diagnosis and treatment of pulmonary hypertension in infancy

Normal pulmonary vascular development in infancy requires maintenance of low pulmonary vascular resistance after birth, and is necessary for normal lung function and growth. The developing lung is subject to multiple genetic, pathological and/or environmental influences that can adversely affect lung adaptation, development, and growth, leading to pulmonary hypertension. New classifications of pulmonary hypertension are beginning to account for these diverse phenotypes, and or pulmonary hypertension in infants due to PPHN, congenital diaphragmatic hernia, and bronchopulmonary dysplasia (BPD). The most effective pharmacotherapeutic strategies for infants with PPHN are directed at selective reduction of PVR, and take advantage of a rapidly advancing understanding of the altered signaling pathways in the remodeled vasculature.

Effect of milrinone on short term outcome of patients with myocardial dysfunction undergoing off-pump coronary artery bypass graft: a randomized clinical trial

Myocardial dysfunction is a major complication in cardiac surgery that needs inotropic support. This study evaluates the effect of milrinone on patients with low ventricular ejection fraction undergoing off- pump coronary artery bypass graft (OPCAB). The present study is designed to evaluate the effect of milrinone on myocardial dysfunction. Eighty patients with low ventricular ejection fraction (<35%), candidate for elective OPCAB, were enrolled in this study. They were randomly assigned to two groups. One group received milrinone (50 μg/kg) intravenously and another group received a saline as placebo followed by 24 hours infusion of each agent (0.5 μg/kg/min). Short outcome of patients such as hemodynamic parameters and left ventricular ejection fraction were variables evaluated. Serum levels of creatine phosphokinase, the MB isoenzyme of creatine kinase, occurrence of arrhythmias and mean duration of mechanical ventilation were significantly lower in milrinone group (P&lt;0.05). The mean post operative left ventricular ejection fraction was significantly higher in milrinone group (P=0.031). There were no statistical significant differences between the two groups in terms of intra-aortic balloon pump, inotropic support requirement, myocardial ischemia, myocardial infarction, duration of inotropic support, duration of intensive care unit stay, mortality and morbidity rate. Administration of milrinone in patients undergoing OPCAB with low ventricular ejection fraction is useful and effective.

[Characteristics of circulatory disturbance and the treatment of severe hand-foot-and-mouth disease]

OBJECTIVE

To investigate the characteristics of circulatory disturbance and treatment of severe hand-foot-and-mouth disease (HFMD).

METHOD

The clinical characteristics, laboratory findings, therapy and outcome of 22 severe HFMD patients were retrospectively analyzed.

RESULT

All the 22 severe HFMD patients came from the countryside. All these patients had encephalitis. Fifteen cases had myocardial injury. All had symptoms of sympathetic excitation and 17 cases had hypertension [(128 ± 16)/(81 ± 14) mm Hg (1 mm Hg = 0.133 kPa)]. Fourteen cases had exacerbation with rapid decline of blood pressure [(61 ± 12)/(33 ± 12) mm Hg]. In cardiorespiratory failure stage, 13 patients had neurogenic pulmonary edema accompanied by circulatory failure and 12 cases had a lower glasgow scores (less than 7). Myocardial injury and ECG change were found in some cases. Inotropic and pressor drugs were given in patients with circulatory collapse. Five cases received fluid resuscitation due to refractoriness to inotropic drugs. Nine patients received blood purification. Seventeen survived and 5 cases died due to circulatory failure.

CONCLUSION

Circulation failure of severe HFMD is the main cause of death. Early and appropriate circulation support is very important to reduce mortality.

Preoperative inhalation of milrinone attenuates inflammation in patients undergoing cardiac surgery with cardiopulmonary bypass

OBJECTIVES

The purpose of this study was to evaluate the effect of preoperative inhalation of milrinone on cardiopulmonary bypass (CPB)-related inflammation.

SUBJECTS AND METHODS

A total of 30 patients undergoing cardiac surgery were recruited and randomized for preoperative inhalation of milrinone (Mil group) or normal saline (NS group), respectively. Each group had 15 patients. Their hemodynamic parameters were measured and blood samples were obtained longitudinally. The levels of serum interleukin (IL-6), tumor necrosis factor-α (TNF-α), and matrix metalloproteinase (MMP)-9 were determined by ELISA.

RESULTS

The levels of serum IL-6, TNF-α, and MMP-9 significantly increased at the end of cardiac surgery and remained high for 24 h in both groups of patients. However, the levels of proinflammatory cytokines at the end of cardiac surgery in the Mil group of patients were significantly lower than those of the NS group of patients.

CONCLUSIONS

Our data indicated that preoperative inhalation of milrinone significantly mitigated CPB-related inflammation.

Relation of milrinone after surgery for congenital heart disease to significant postoperative tachyarrhythmias

Milrinone reduces the risk of low cardiac output syndrome for some pediatric patients after congenital heart surgery. Data from adults undergoing cardiac surgery suggest an association between milrinone and an increased risk of postoperative arrhythmias. We tested the hypothesis that milrinone is an independent risk factor for tachyarrhythmias after congenital heart surgery. Subjects undergoing congenital heart surgery at our institution were consecutively enrolled for 38 months, through September 2010. The data were prospectively collected, including a review of full-disclosure telemetry and the medical records. Within 38 months, 603 enrolled subjects underwent 724 operative procedures. The median age was 5.5 months (range 0.0 to 426), the median weight was 6.0 kg (range 0.7 to 108), and the cohort was 45% female. The overall arrhythmia incidence was 50%, most commonly monomorphic ventricular tachycardia (n = 85, 12%), junctional ectopic tachycardia (n = 69, 10%), accelerated junctional rhythm (n = 58, 8%), and atrial tachyarrhythmias (including atrial fibrillation, atrial flutter, and ectopic or chaotic atrial tachycardia, n = 58, 8%). Multivariate logistic regression analysis demonstrated that independent of age <1 month, the use of cardiopulmonary bypass, the duration of cardiopulmonary bypass, Risk Adjusted classification for Congenital Heart Surgery, version 1, score >3, and the use of epinephrine or dopamine, milrinone use on admission to the cardiac intensive care unit remained independently associated with an increase in the odds of postoperative tachyarrhythmia resulting in an intervention (odds ratio 2.8, 95% confidence interval 1.3 to 6.0, p = 0.007). In conclusion, milrinone use is an independent risk factor for clinically significant tachyarrhythmias in the early postoperative period after congenital heart surgery.

[Effect of inhaling specific phosphodiesterase inhibitor on lung injury induced by cardiopulmonary bypass]

OBJECTIVE

To evaluate the effect of pretreatment by inhaling specific phosphodiesterase inhibitor on lung injury induced by cardiopulmonary bypass (CPB).

METHODS

From April 2010 to November 2010, 30 patients were divided randomly into two groups: control group (n = 15) and milrinone group (n = 15). In milrinone group, 5 mg milrinone diluted by 5ml normal saline was inhaled per 8 h two days pre-operation. In control group, only 10 ml normal saline was inhaled. Blood samples were drawn from ulnar vein and radial artery pre-operation (T(0)), 30 min post-aortic unclamping (T(1)), at the end of operation (T(2)), 24 h, 72 h and 7 d post-operation (T(3)-T(5)). The following parameters were determined: TNF-α (tumor necrosis factor-alpha), IL-6 (interleukin-6), HSCRP (high-sensitivity C-reactive protein), MDA (malondialdehyde), MPO (myeloperoxidase) level and leucocyte count ratio of venous and arterial blood. And the values of pulmonary vascular resistance (PVR) and oxygenation index (OI) were measured through a Swan-Ganz catheter at the first 5 time points.

RESULTS

PVR rose while OI declined at post-operation. But the range of above-mentioned indices in milrinone group was significantly smaller than that in control group. And the indices recovered much earlier in milrinone group. The levels of TNF-α, IL-6, HSCRP, MDA, MPO and leucocyte count ratio were not significantly different at T(0) between two groups and increased significantly after CPB in both groups. But the level of TNF-α (ng/L) was significantly lower at T(2), T(4), T(5) in milrinone group than that in control group (60 ± 5 vs 79 ± 7, 29 ± 6 vs 40 ± 8, 18 ± 5 vs 28 ± 7, all P < 0.05). The levels of IL-6 and MDA were significantly lower at T(1)-T(4) in milrinone group. The level of HSCRP became elevated post-operatively in both groups and reached its peak at 24 h post-operation, especially in control group. The level of MPO (µg/L) was significantly lower at T(2), T(3) and T(5) (134 ± 20 vs 190 ± 23, 142 ± 28 vs 178 ± 20, 65 ± 9 vs 75 ± 11, all P < 0.05). And the V/A ratio was significantly lower at T(1)-T(3) in milrinone group than in control group (1.12 ± 0.11 vs 1.37 ± 0.09, 1.07 ± 0.07 vs 1.25 ± 0.07, both P < 0.01).

CONCLUSION

Inhaled milrinone may protect the lungs from acute injury induced by CPB. Inhaling milrinone is safe and feasible for the prevention of acute CPB-induced injury.

Milrinone for persistent pulmonary hypertension of the newborn

BACKGROUND

Persistent pulmonary hypertension of the newborn (PPHN) is a clinical syndrome characterized by suboptimal oxygenation as a result of sustained elevation in pulmonary vascular resistance after birth. Currently, the therapeutic mainstay for PPHN is optimal lung inflation and selective vasodilatation with inhaled nitric oxide (iNO). However, iNO is not available in all countries and not all infants will respond to iNO. Milrinone is a phosphodiesterase III inhibitor which induces pulmonary vasodilatation by its actions through a cyclic adenylate monophosphate mediated signaling pathway.

OBJECTIVES

To assess efficacy and safety in infants with PPHN either treated with: milrinone compared with placebo or no treatment; milrinone compared with iNO; milrinone as an adjunct to iNO compared with iNO alone; milrinone compared with potential treatments for PPHN other than iNO.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 2, 2010), MEDLINE and EMBASE databases from their inception until January 2010. We searched the reference lists of potentially relevant studies without any language restriction.

SELECTION CRITERIA

Fully published randomized controlled trials (RCTs) and quasi-RCTs comparing milrinone with placebo, iNO or potential treatments other than iNO in neonates with PPHN were included if trials reported any clinical outcome.

DATA COLLECTION AND ANALYSIS

We found no studies meeting the criteria for inclusion in this review.

MAIN RESULTS

We found no studies meeting the criteria for inclusion in this review.

AUTHORS' CONCLUSIONS

The efficacy and safety of milrinone in the treatment of PPHN are not known and its use should be restricted within the context of RCTs. Such studies should address a comparison of milrinone with placebo (in clinical situations where iNO is not available) or, in well resourced countries, should compare milrinone with iNO or as an adjunct to iNO compared with iNO alone.

Persistent pulmonary hypertension of the newborn refractory to inhaled nitric oxide-treated with milrinone: a case report

Current therapy of persistent pulmonary hypertension of the newborn (PPHN) consists of optimal ventilation, hemodynamic support and selective vasodilatation with inhaled nitric oxide (iNO). We present herein a case of PPHN non-responsive to iNO but treated successfully with a combination of iNO and intravenous milrinone, a phosphodiesterase III inhibitor. This case suggests that the drug may be a useful adjunctive treatment in the management of PPHN.

Postrenal biopsy AVM leading to severe hypertension and dilated cardiomyopathy

A 3-year-old girl with Alport syndrome presented with decompensated heart failure from hypertension-induced cardiomyopathy 6 months following renal biopsy. Selective renal angiography revealed a large left renal arteriovenous fistula (AVF) with poor perfusion to the left renal parenchyma. The AVF was treated by transcatheter embolization using an Amplatzer vascular plug. Her blood pressure normalized after embolization, and her cardiac function normalized over the following 4 months.

Anti-ischemic effects of inotropic agents in experimental right ventricular infarction

BACKGROUND

Right ventricular (RV) function is an important determinant of survival after myocardial infarction. The efficacy of reperfusion therapy might be increased by the cardioprotective action of inotropic agents, which are used for symptomatic therapy in situations with compromised hemodynamics. Therefore, we used a porcine model of RV ischemia and reperfusion (IR) injury to study the influence of milrinone, levosimendan and dobutamine on the extent and degree of myocardial injury.

METHODS

IR injury was induced by temporary ligation of the distal right coronary artery for 90 min, followed by 120 min of reperfusion. Treatment was initiated 30 min after coronary artery occlusion. A bolus of milrinone (n=12; 50 microg/kg) and levosimendan (n=10; 24 microg/kg) was applied in different groups, followed by continuous infusion of the drugs at 0.5 and 0.2 microg/kg/min, respectively. The effects on myocardial injury and inflammation were compared with a control (n=12) and a dobutamine group (n=10), where treatment was started with an infusion of 5 microg/kg/min.

RESULTS

Milrinone and levosimendan reduced the resulting infarct size with respect to the area at risk (41.7+/-10.2%, 45.7+/-8.1%) when compared with the control group (58.3+/-6.1%). In contrast, dobutamine had no effect (55.8+/-7.7%). All drugs reduced the number of neutrophils infiltrating into the different myocardial regions and the circulating levels of interleukin-6. Increased levels of tumor necrosis factor alpha during reperfusion were only abated by milrinone and levosimendan.

CONCLUSIONS

Cardioprotective properties of milrinone and levosimendan were demonstrated for the first time in a clinically relevant model of RV infarction.

The effect of milrinone on metabolism after cardiopulmonary bypass

AIM

The aim of this study was to examine the effects of milrinone on tissue metabolism perioperatively in cardiac surgery patients using extracorporeal circulation, in comparison to adrenaline and placebo. These effects were measured indirectly by measuring serum lactate, base excess and glucose levels at standard intervals.

METHODS

Seventy-seven consecutive patients, who underwent elective cardiac surgery, were allocated in 3 groups. Inotropic support was initiated coming off CPB (cardiopulmonary bypass) if there was evidence of hypotension (mean arterial pressure [MAP] <60 mmHg), after adequate preload (pulmonary capillary wedge pressure [PCWP] >10 mmHg). Milrinone was used in patients with pulmonary hypertension (MPAP >20 mmHg). Group 1 (N.=26) received no inotropes, placebo. Group 2 (N.=32) received adrenaline. Group 3 (N.=19) received adrenaline + milrinone at 0.5 microg/kg/min infusion. Adrenaline was infused at a variable dose (0.01-0.02 microg/kg/min) to achieve a MAP >60 mmHg. The serum lactate, base excess and glucose levels were measured at standard intervals in all 3 groups. Diabetic, hepatic or renal failure patients (serum creatinine >2 mg/dL), were excluded from the study. Patient demographic and clinical characteristics were similar in all 3 groups.

RESULTS

Repeated measure analysis of variance between groups showed significantly lower serum lactate levels and higher base excess in the milrinone group (P<0.05), after 2 to 4 hours of treatment. Serum glucose levels were higher in the adrenaline group (P=0.01). There were no immediate complications, morbidity or mortality in the study groups.

CONCLUSION

These findings suggest that milrinone has a beneficiary effect on aerobic tissue metabolism after extracorporeal circulation, reflected on serum lactate, base excess and glucose levels, possibly due to a combination of positive inotropic and peripheral vasodilatory effect of the drug.

Inhaled iloprost to control pulmonary artery hypertension in patients undergoing mitral valve surgery: a prospective, randomized-controlled trial

BACKGROUND

Pulmonary hypertension (PHT) is common in patients undergoing mitral valve surgery and is an independent risk factor for the development of acute right ventricular (RV) failure. Inhaled iloprost was shown to improve RV function and decrease RV afterload in patients with primary PHT. However, no randomized-controlled trials on the intraoperative use of iloprost in cardiac surgical patients are available. We therefore compared the effects of inhaled iloprost vs. intravenous standard therapy in cardiac surgical patients with chronic PHT.

METHODS

Twenty patients with chronic PHT undergoing mitral valve repair were randomized to receive inhaled iloprost (25 microg) or intravenous nitroglycerine. Iloprost was administered during weaning from cardiopulmonary bypass (CPB). Systemic and pulmonary haemodynamics were assessed with pulmonary artery catheterization and transoesophageal echocardiography. Milrinone and/or inhaled nitric oxide were available as rescue medication in case of failure to wean from CPB.

RESULTS

Inhaled iloprost selectively decreased the pulmonary vascular resistance index after weaning from CPB (208 +/- 108 vs. 422 +/- 62 dyn.s/cm(5)/m(2), P<0.05), increased the RV-ejection fraction (29 +/- 3% vs. 22 +/- 5%, P<0.05), improved the stroke volume index (27 +/- 7 vs. 18 +/- 6 ml/m(2), P<0.05) and reduced the transpulmonary gradient (10 +/- 4 vs. 16 +/- 3 mmHg, P<0.05). In all patients receiving inhaled iloprost, weaning from CPB was successful during the first attempt. In contrast, three patients in the control group required re-institution of CPB and had to be weaned from CPB using rescue medication.

CONCLUSIONS

In patients with pre-existing PHT undergoing mitral valve surgery, inhaled iloprost is superior to intravenous nitrogylycerine by acting as a selective pulmonary vasodilator, reducing RV afterload and moderately improving RV-pump performance.

Long-term support with milrinone prior to cardiac transplantation in a neonate with left ventricular noncompaction cardiomyopathy

A 2-week-old female infant presented with acute decompensated left ventricular failure. Echocardiography diagnosed left ventricular noncompaction cardiomyopathy with dilated phenotype and a left ventricular shortening fraction <10%. The infant was mechanically ventilated for 2 weeks and then successfully extubated. She was maintained on intravenous milrinone for 6 months until she underwent successful orthotopic heart transplantation. Young children can be supported with inotropes for prolonged periods while awaiting heart transplantation.