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BACKGROUND: Pulmonary hypertension (PH) and right ventricular (RV) dysfunction are major complications in cardiac surgery. Intraoperative management of patients at high risk of RV failure should aim to reduce RV afterload and optimize RV filling pressures, while avoiding systemic hypotension, to facilitate weaning from cardiopulmonary bypass (CPB). Inhaled epoprostenol and inhaled milrinone (iE&iM) administered in combination before CPB may represent an effective strategy to facilitate separation from CPB and reduce requirements for intravenous inotropes during cardiac surgery. Our primary objective was to report the rate of positive pulmonary vasodilator response to iE&iM and, second, how it relates to perioperative outcomes in cardiac surgery. METHODS: This is a retrospective cohort study of consecutive patients with PH or RV dysfunction undergoing on-pump cardiac surgery at the Montreal Heart Institute from July 2013 to December 2018 (n = 128). iE&iM treatment was administered using an ultrasonic mesh nebulizer before the initiation of CPB. Demographic and baseline clinical data, as well as hemodynamic, intraoperative, and echocardiographic data, were collected using electronic records. An increase of 20% in the mean arterial pressure (MAP) to mean pulmonary artery pressure (MPAP) ratio was used to indicate a positive response to iE&iM. RESULTS: In this cohort, 77.3% of patients were responders to iE&iM treatment. Baseline systolic pulmonary artery pressure (SPAP) (odds ratio [OR], 1.63; 95% confidence interval [CI], 1.24-2.16 per 5 mm Hg; P = .0006) was found to be a predictor of pulmonary vasodilator response, while a European System for Cardiac Operative Risk Evaluation (EuroSCORE II) score >6.5% was a predictor of nonresponse to treatment (≤6.5% vs >6.5% [reference]: OR, 5.19; 95% CI, 1.84-14.66; P = .002). Severity of PH was associated with a positive response to treatment, where a higher proportion of responders had MPAP values >30 mm Hg (42.4% responders vs 24.1% nonresponders; P = .0237) and SPAP values >55 mm Hg (17.2% vs 3.4%; P = .0037). Easier separation from CPB was also associated with response to iE&iM treatment (69.7% vs 58.6%; P = .0181). A higher proportion of nonresponders had a very difficult separation from CPB and required intravenous inotropic drug support compared to responders, for whom easy separation from CPB was more frequent. Use of intravenous inotropes after CPB was lower in responders to treatment (8.1% vs 27.6%; P = .0052). CONCLUSIONS: A positive pulmonary vasodilator response to treatment with a combination of iE&iM before initiation of CPB was observed in 77% of patients. Higher baseline SPAP was an independent predictor of pulmonary vasodilator response, while EuroSCORE II >6.5% was a predictor of nonresponse to treatment. (Anesth Analg 2023;136:282-94)
KEY POINTS• Question: Can a combination of inhaled epoprostenol and inhaled milrinone (iE&iM) administered before cardiopulmonary bypass (CPB) provide a positive pulmonary vasodilator response? • Findings: A positive pul...
Regional cerebral oxygen saturation (rSo 2 ) obtained from near-infrared spectroscopy (NIRS) provides valuable information during cardiac surgery. The rSo 2 is calculated from the proportion of oxygenated to total hemoglobin in the cerebral vasculature. Root O3 cerebral oximetry (Masimo) allows for individual identification of changes in total (ΔcHbi), oxygenated (Δo 2 Hbi), and deoxygenated (ΔHHbi) hemoglobin spectral absorptions. Variations in these parameters from baseline help identify the underlying mechanisms of cerebral desaturation. This case series represents the first preliminary description of Δo 2 Hbi, ΔHHbi, and ΔcHbi variations in 10 cardiac surgical settings. Hemoglobin spectral absorption changes can be classified according to 3 distinct variations of cerebral desaturation. Reduced cerebral oxygen content or increased cerebral metabolism without major blood flow changes is reflected by decreased Δo 2 Hbi, unchanged ΔcHbi, and increased ΔHHbi Reduced cerebral arterial blood flow is suggested by decreased Δo 2 Hbi and ΔcHbi, with variable ΔHHbi. Finally, acute cerebral congestion may be suspected with increased ΔHHbi and ΔcHbi with unchanged Δo 2 Hbi. Cerebral desaturation can also result from mixed mechanisms reflected by variable combination of those 3 patterns. Normal cerebral saturation can occur, where reduced cerebral oxygen content such as anemia is balanced by a reduction in cerebral oxygen consumption such as during hypothermia. A summative algorithm using rSo 2 , Δo 2 Hbi, ΔHHbi, and ΔcHbi is proposed. Further explorations involving more patients should be performed to establish the potential role and limitations of monitoring hemoglobin spectral absorption signals. (Anesth Analg 2022;135:1304-14) GLOSSARY ΔcHbi = index representing changes in the total (ΔHHbi + Δo 2 Hbi) hemoglobin component of the rSo 2 ; ΔHHbi = index representing changes in the deoxygenated hemoglobin component of the rSo 2 ; Δo 2 Hbi = index representing changes in the oxygenated hemoglobin component of the rSo 2 ; Cao 2 = arterial oxygen content; CBF = cerebral blood flow; CMRo 2 = cerebral metabolic rate of oxygen; COVID-19 = coronavirus disease 2019; CPB = cardiopulmonary bypass; dP/dT = change in the pressure over time ratio; HITS = high-intensity transient signal; IT = intratracheal; LE = lower extremity; LV = left ventricular; LVEF = left ventricular ejection fraction; NIRS = near-infrared spectroscopy; pEEG = processed electroencephalography; Pfa = femoral artery pressure; Ppa = pulmonary artery pressure; Pra = radial arterial pressure; Prv = right ventricular pressure; rSo 2 = regional oxygen saturation; RV = right ventricular; SVC = superior vena cava; TCD = transcranial Doppler; UE = upper extremity
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