Right Heart Function in Critically Ill Patients at Risk for Acute Right Heart Failure: A Description of Right Ventricular-Pulmonary Arterial Coupling, Ejection Fraction and Pulmonary Artery Pulsatility Index.

BACKGROUND: The gold standard for right heart function is the assessment of right ventricular-pulmonary arterial coupling defined as the ratio of arterial to end-systolic elastance (Ea/Emax). This study demonstrates the use of the volumetric pulmonary artery (PA) catheter for estimation of Ea/Emax and describes trends of Ea/Emax, right ventricular ejection fraction (RVEF), and pulmonary artery pulsatility index (PAPi) during initial 48hours of resuscitation in the trauma surgical intensive care unit (ICU). METHODS: Review of prospectively collected data for 32 mechanically ventilated adult trauma and emergency general surgery patients enrolled within 6hours of admission to the ICU. Haemodynamics, recorded every 12hours for 48hours, were compared among survivors and non-survivors to hospital discharge. RESULTS: Mean age was 49±20 years, 69% were male, and 84% were trauma patients. Estimated Ea/Emax was associated with pulmonary vascular resistance and inversely related to pulmonary arterial capacitance and PA catheter derived RVEF. Seven (7) trauma patients did not survive to hospital discharge. Non-survivors had higher estimated Ea/Emax, suggesting right ventricular-pulmonary arterial uncoupling, with a statistically significant difference at 48hours (2.3±1.7 vs 1.0±0.58, p=0.018). RVEF was significantly lower in non-survivors at study initiation and at 48hours. PAPi did not show a consistent trend. CONCLUSIONS: Estimation of Ea/Emax using volumetric PA catheter is feasible. Serial assessment of RVEF and Ea/Emax may help in early identification of right heart dysfunction in critically ill mechanically ventilated patients at risk for acute right heart failure.

Relationship of Right Ventricular Size and Function with Respiratory Status in Duchenne Muscular Dystrophy.

The relationship between pulmonary function and right ventricle (RV) in Duchenne muscular dystrophy (DMD) has not been evaluated. Using cardiac magnetic resonance (CMR), we describe the relationship of RV size and function with spirometry in a DMD cohort. Fifty-seven boys undergoing CMR and pulmonary function testing within 1 month at a single center (2013-2015) were enrolled. Comparisons of RV ejection fraction (RVEF) and end-diastolic volume index (RVEDVI) were made across categories of percent forced vital capacity (FVC%), and relationships were assessed. Mean age was 15.5 ± 3.5 years. Spirometry and CMR were performed within 3.9 ± 4.1 days. Median FVC% was 92.0 % (67.5-116.5 %). Twenty-three (40 %) patients had abnormal FVC% (<80 %) of which 13 (57 %) had mild (FVC% 60-79 %), 6 (26 %) had moderate (FVC% 40-59 %), and 4 (17 %) had severe (FVC <40 %) reductions. Mean RVEF was 58.3 ± 3.7 %. Patients with abnormal FVC% were older and had lower RVEF and RVEDVI. Both RVEF and RVEDVI were significantly associated with FVC% (r = 0.31, p = 0.02 and r = 0.39, p = 0.003, respectively). In a large DMD cohort, RVEF and RVEDVI were related to FVC%. Worsening respiratory status may guide monitoring of cardiac function in these patients.

Role of inferior vena cava filter implantation in preventing pulmonary embolism.

A retrospective review of all patients undergoing IVC filter implantation at Shifa International Hospital, Islamabad, from June 2004 to June 2006 was conducted to study the indications of inferior vena cava (IVC) filter use and impact on short-term morbidity/mortality. A total of 17 patients received IVC filters. Five patients were excluded due to data loss. One month clinical follow-up was available for 12 patients and 6 months follow-up was also available for 4 of 12 patients. The underlying disease was deep venous thrombosis (DVT) with pulmonary embolism (PE) in 6 (50%), DVT without PE in 4 (33.3%) and PE with negative duplex scan for DVT in 2 (16.6%) patients, respectively. Indications for IVC filter implantation were DVT and/or PE with contraindication to anticoagulation in 8 (66.7%) and DVT and/or PE with complications of anticoagulation in 4 (33.3%) patients. No procedure-related complications were noted in all 17 patients. Three patients (25%) died of non-PE related causes during the 1st month. There were no PE related mortalities at 6 months. This data set indicates that IVC filter implantation is a safe procedure with no short-term morbidity/mortality and potential long-term mortality benefit.