experimental & clinical cardiology

EXPERIMENTAL & CLINICAL CARDIOLOGY

Volume 20, Issue 5, 2014

Title: "Intraoperative Efficacy of Brief Inhalation of Milrinone on Elevated Pulmonary Arterial Pressure in Patients Undergoing Mitral Valve Surgery Due to Mitral Regurgitation" Authors: Songam Lee, Tae-Yop Kim and Chang Young Jeong

How to reference: Intraoperative Efficacy of Brief Inhalation of Milrinone on Elevated Pulmonary Arterial Pressure in Patients Undergoing Mitral Valve Surgery Due to Mitral Regurgitation/Songam Lee, Tae-Yop Kim and Chang Young Jeong/Exp Clin Cardiol Vol 20 Issue5 pages 3369-3378 / 2014

Intraoperative Efficacy of Brief Inhalation of Milrinone on Elevated Pulmonary Arterial Pressur...

Experimental and Clinical Cardiology

Intraoperative efficacy of brief inhalation of milrinone on elevated pulmonary arterial pressure in patients undergoing mitral valve surgery due to mitral regurgitation Original Article Tae-‐‑Yop Kim, MD, PhD1, Songam Lee, MD2, Chang Young Jeong, MD, PhD3 1.

Department of Anesthesiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul Korea

2.

Department of Chest Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul Korea

3.

Department of Anesthesiology and Pain Medicine, Eulji University Hospital, Daejeon, Korea

Abstract

PAP due to severe MR. This result suggests its possible

The effect of intraoperative inhalation of milrinone (IH) on

efficacy for intraoperative management of pulmonary

pulmonary artery pressure (PAP) was analyzed and

hypertension.

compared to that of intravenous milrinone (IV) in patients

undergoing mitral valve surgery due to severe mitral

Key words

regurgitation (MR). After anesthesia induction and before

Inhaled milrinone, intravenous milrinone, pulmonary artery

initiating cardiopulmonary bypass, patients received either

pressure.

a 10-‐‑min inhalation of milrinone (1 mg/ml), (Group-‐‑IH,

n=10) or 50 µμg/kg of intravenous (IV) milrinone (Group-‐‑IV,

Introduction

n=10), hemodynamic change before and 10 min after

Perioperative pulmonary hypertension (PHT), an

administering milrinone were analyzed in both groups.

independent risk factor for cardiac surgery [1,2], is

Mean PAP and PVR significantly reduced after drug

frequently associated with chronic mitral valve

administration in both groups (all p 50 mmHg by using the peak velocity

propofol effect-‐‑site concentration of 2.0-‐‑2.5 µμg/ml.

of tricuspid valve regurgitation flow in preoperative

Additional fentanyl at 10-‐‑30 µμg/kg/h and rocuronium at 20-‐‑

transthoracic echocardiography.

30 mg/h were administered to maintain anesthesia, and the

Preoperative exclusion criteria included preoperative

propofol concentration was adjusted to maintain a BIS score

Exp Clin Cardiol, Volume 20, Issue 5, 2014 - Page 3370


of 40-‐‑60. After tracheal intubation, volume-‐‑controlled

Delivery of the Study Drug

ventilation of oxygen with air (FiO2 0.6, flow rate 100

After performing the sternotomy and achieving stable

ml/kg/min) was started with a tidal volume of 10 ml/kg,

hemodynamics, but before the initiation of CPB, the study

respiration rate of 12-‐‑14/min, inspiration:expiration ratio of

drugs were administered; inhaled milrinone and IV placebo

1:2, and peak airway pressure lower than 25 cmH2O. Then,

(0.9% normal saline 0.05 ml/kg) or inhaled placebo (distilled

the respiration rate was adjusted to maintain an end-‐‑tidal

water) and an IV bolus of milrinone (50 µμg/kg) were

CO2 of 35-‐‑40 mmHg.

administered in Group-‐‑IH and Group-‐‑IV, respectively.

An introducer and a pulmonary artery catheter were placed

Milrinone was used at its commercial concentration (1.0

in the right internal jugular vein. A transesophageal

mg/ml) for both inhalation and IV administration. The

echocardiography (TEE) probe was placed, and

reservoir of a nebulizer (MiniHeart™; Westmed, Tucson,

intraoperative TEE was used to monitor ventricular and

AZ, USA) was placed in the proximal end of the inspiratory

valvular function throughout the operation. The left

limb of ventilator circuit (90 cm proximal to the Y-‐‑piece) and

ventricular (LV) ejection fraction was measured using a

it was filled with milrinone or placebo. A filter for heat-‐‑

modification of Simpson’s method from the midesophageal

moisture exchange was placed in the distal end of the

4 or 2 chamber view of two-‐‑dimensional TEE images as

expiratory limb of ventilator.

appropriate.

The milrinone or placebo in the reservoir was nebulized

During and after anesthesia induction and obtaining

with a fixed operating flow at 2 L/min of O2 (as per the

vascular access for hemodynamic monitoring, synthetic

manufacturer’s recommendation) and delivered over 10 min

hydroxyethylstarch (Voluven™; Fresenius Kabi, Bad

at a ventilator flow rate of 100 ml/kg/min to avoid

Homberg, Germany) was administered as needed to

rebreathing the expiratory flow, which may produce

maintain stable hemodynamics, and bolus phenyepherine

contamination or interaction between the nebulized

50-‐‑100 µμg was administered intravenously to treat any

milrinone and CO2 absorbent. The aerosol size and delivery

refractory hypotension (MAP < 60 mmHg) persisting for

rate of the nebulized drug were assumed to be 1.0-‐‑2.5 µμm

more than 1 min with intravascular volume administration.

and 45-‐‑65 µμL per gas flow, respectively, according to the

After delivering the study drugs and collecting data, CPB

manufacturer’s manual for the nebulizer. Excess inspiratory

with moderate hypothermia (rectal temperature 28-‐‑30ºC)

gas flow from the nebulizer was compensated for by

via crystalloid cardioplegia was used during the surgical

adjustment of minute ventilation settings on the ventilator,

procedure. The MAP was maintained at 60-‐‑75 mmHg by

keeping minute ventilation constant. Inspiratory oxygen

adjusting the pump flow and administering 50 µμg boluses of

fraction (FiO2) was kept constant throughout the procedure.

phenylepherine during the CPB period.

If MAP decreased below 60 mmHg, inhalation of the study

The IV milrinone infusion (0.5 µμg/kg/min) was started at the

drug was stopped and the patient excluded from the study.

release of the aortic cross-‐‑clamp and a continuous infusion

of norepinehrine was started at a rectal temperature of 35ºC

Hemodynamic Data

as needed; its dosage was titrated to wean the patient from

The following data were obtained before and 10 min after

CPB and to maintain the optimal hemodynamics during the

completely administering the study drug: mean arterial

post-‐‑CPB period in both groups.

pressure (MAP), mean pulmonary arterial pressure (MPAP),

central venous pressure (CVP), pulmonary arterial

Exp Clin Cardiol, Volume 20, Issue 5, 2014 - Page 3371


occlusion pressure (PAOP), the transpulmonary pressure

significantly different (Table 3).

gradient (TPG = MPAP–PAOP), thermodilution cardiac

The SVR and PVR after milrinone administration in Group-‐‑

output (CO), systemic vascular resistance (SVR), pulmonary

IH were significantly greater than those in Group-‐‑IV

vascular resistance (PVR), arterial O2 tension (PaO2), mixed

(p