Diaphragm dysfunction, lung aeration loss and weaning-induced pulmonary oedema in difficult-to-wean patients

Background Diaphragm dysfunction and weaning-induced pulmonary oedema are commonly involved during weaning failure, but their physiological interactions have been poorly reported. Our hypothesis was that diaphragm dysfunction is not particularly associated with weaning-induced pulmonary oedema. Methods It was a single-centre and physiological study conducted in patients who had failed a first spontaneous breathing trial and who underwent a second trial. The diaphragm function was evaluated by measuring the tracheal pressure generated in response to a bilateral magnetic phrenic nerves stimulations. Weaning-induced pulmonary oedema was diagnosed in case of failure of the spontaneous breathing trial if patients exhibited signs of plasma concentration or echocardiographic diagnosis of pulmonary artery occlusion pressure elevation. Results Fifty-three patients were included and 31/53 (58%) failed the spontaneous breathing trial, including 24/31 (77%) patients with weaning-induced pulmonary oedema. Diaphragm dysfunction was present in 33/53 (62%) patients. Diaphragm dysfunction or weaning-induced pulmonary oedema were present in 26/31 (84%) of the patients who failed the spontaneous breathing trial. Weaning-induced pulmonary oedema occurred in 20/33 (61%) patients with a diaphragm dysfunction and in 4/20 (20%) patients without (p = 0.005). Conclusion Weaning-induced pulmonary oedema was three times more frequent in case of diaphragm dysfunction. Even in case of diaphragm dysfunction, physicians might be encouraged to investigate the presence of weaning-induced pulmonary oedema during weaning failure.

Prediction of fluid responsiveness in the immediate post-operative period of cardiac surgery

Background: Prediction of fluid responsiveness can identify patients who will benefit from fluid loading in the immediate postoperative period of cardiac surgery. Several hemodynamic parameters may help identify those who will benefit from hydration. This study aimed to identify and compare the parameters that predict fluid responsiveness in post-cardiac surgery patients. Methodology: This prospective cohort study included 101 post-cardiac surgery patients. Hemodynamic parameters were recorded at baseline and after an 8 mL/kg IV fluid challenge. Fluid responders are those with an increase in stroke volume of ≥15%. Multivariate analysis was used to identify independent predictors of fluid responder status. Sensitivity and specificity analyses were done to determine the predictive accuracy of each parameter. Results: The rate of fluid responsiveness was 54.5%. Independent predictors were: central venous pressure (CVP) ≤6 mmHg (p=0.001), pulmonary artery occlusion pressure (PAOP) ≤12 mmHg (p=0.016), PAOP increase by ≥7 mmHg (p=0.002), pulse pressure variability (PPV) >12% (p<0.001), PPV decrease by >5% (p=0.049) and weight (p=0.04). PPV was the most sensitive (92%) and specific (74%); while PAOP was the least sensitive (70%) and CVP the least specific (51%). PPV had the highest ability to discriminate fluid responders (AUC 0.83) compared to PAOP (AUC 0.21) and CVP (AUC 0.40) (p<0.0001). Conclusion: PPV (a dynamic index) is superior to CVP and PAOP (static indices) in discriminating fluid responders in adult patients who underwent cardiac surgery. PPV is the favored tool to guide initiation of fluid therapy in this clinical setting.

Predictors to Intravenous Fluid Responsiveness

Management with intravenous fluids can improve cardiac output in some surgical patients. Management with static preload indicators, such as central venous pressure and pulmonary artery occlusion pressure, has not demonstrated a suitable relationship with changes in the cardiac output induced by intravenous fluid therapy. Dynamic indicators, such as the variability of arterial pulse pressure or stroke volume variation, have demonstrated a suitable relationship. Since improvement in cardiac output does not guarantee an adequate perfusion pressure, in patients with hypotension, it is also necessary to know whether arterial pressure will also increase with intravenous fluid therapy. In this regard, the functional assessment of arterial load by dynamic arterial elastance could help to determine which patients will improve not only their cardiac output but also their mean arterial pressure.

Pengukuran CVC pada pasien Sepsis, Apakah terdapat keuntungan?

Sepsis adalah penyebab utama 10 kematian di Amerika Serikat. Sekitar 751.000 kasus sepsis berat per tahun terjadi di Amerika Serikat, dengan angka kematian 28,6% dengan biaya tahunan hampir 167 juta US dollar. Sepsis juga terjadi seluruh dunia dengan rata-rata 18 juta kasus sepsis berat terjadi setiap tahun, yang menewaskan sekitar 1400 orang setiap hari dan menimbulkan biaya kesehatan dari US $ 9,4 miliar di negara-negara Eropa Pedoman dari The Surviving Sepsis Campaign untuk pengelolaan berat sepsis dan syok septik diterbitkan pada tahun 2004. Penekanan dari pedoman tersebut yaitu resusitasi awal yang bertujuan tercapainya early goal-directed therapy (EGDT) . Tekanan vena sentral secara umum lebih berguna untuk membantu menentukan penyebab dari suatu masalah daripada mendeteksi suatu masalah pada pemantauan hemodinamik. CVP mengukur tekanan pada atrium kanan yang bisa menggambarkan tekanan akhir diastolik atau end diastolic pressure (EDP). Preload ventrikel lebih erat kaitannya dengan volume akhir diastolik ventrikel atau end diastolic ventricle (EDV) dibandingkan tekanannya, karena itu penting untuk mengetahui hubungan antara EDP dan EDV, di mana hubungan ini tergantung dari compliance ventrikel. Pengukuran CVP dan pulmonary artery occlusion pressure (PAOP) merupakan pengukuran yang bersifat statis, berbeda dengan pegukuran yang bersifat dinamis seperti pulse pressure variaton (PPV), systolic pressure variation (SPV) atau stroke volume variation (SVV), echocardiography vena-cava diameter dan esophageal Doppler aortic blood flow yang selalu berubah pada saat bernafas, hal ini mengakibatkan pengukuran yang bersifat dinamis lebih representatif untuk memprediksi dalam hal kecukupan cairan pada pasien. Pengukuran yang bersifat stastis tidak menggambarkan kecukupan cairan pada pasien. Perubahan tahun 2015 berdasarkan The leadership of the Surviving Sepsis Campaign menyatakan bahwa pemasangan CVC untuk memonitor tekanan vena sentral (CVP) dan saturasi oksigen vena sentral (ScvO2) bukan suatu keharusan pada semua pasien dengan syok sepsis yang sudah mendapatkan pemberian antibiotik dan resusitasi cairan