The PIEPEAR Workflow: A Critical Care Ultrasound Based 7-Step Approach as a Standard Procedure to Manage Patients with Acute Cardiorespiratory Compromise, with Two Example Cases Presented
(1) No evidence of dysfunction of heart and lung before admission
(2) Septic shock when admitted to ICU, complicated intra-abdominal infections with Escherichia coli as the pathogen. After drainage of ascites, antibiotic therapy, fluid resuscitation, and other supportive treatments, the patient improved, presented as normal temperature, decreasing norepinephrine and normal urine output, etc.
(3) Newly presented fever again, with the highest temperature of 38.8°C, as well as increasing norepinephrine to maintain blood pressure, deterioration of liver function, coagulation, and oxygenation. ABG analysis demonstrated the following: pH 6.988; PaO2 46.3mmHg with a FiO2 0.3 (PaO2 / FiO2 ratio of 154, PaCO2 147.7mmHg, BE -19mmol/L and lactate 9.70mmol/L.
3. Focused exam launched
Heart browse: no circumstances that need immediate life-saving intervention or cardiologist emergency consultation, mild to moderate tricuspid valve regurgitation, and left ventricle apex balloon (Figure 5(a)) IVC exam: hypovolemia as IVC diameter <1cm(Figure 5(b)), fluid responsiveness as dIVC18% RV exam: no right ventricular failure that may harm the function of left ventricle or misleading the therapy Diastole of left heart: no evidence of diastolic dysfunction and PAOP elevated Systole of left heart: hyperdynamic, mild decrease in apex contraction Afterload: severely decreased
Right lung massive consolidation (from the 2nd right region to the 6th right region, Figure 5(c))
4. Pathophysiologic changes reported
Hypovolemia with fluid responsiveness, severe decreased systemic vascular resistance which indicate hyperdynamic shock; acute respiratory failure caused by major consolidation and mismatch of the ventilation and blood flow
5. Etiology explored
Hospital acquired pneumonia? Septic shock? WBC, PCT, lactate, blood and ETA culture, PICCO, sonography for the abdomen are needed
6. Action
Fluid resuscitation guided by PICCO and CCUS; norepinephrine titration to MAP goal, use intravenous hydrocortisone if not achievable; monitoring lactate clearance and urine output to adjust above measures; titrate PEEP, recruitment the lung if it could be, deep sedation with neuromuscular blocking drugs, lung protect. If need, consider ECMO.
Administrate broad-spectrum antibiotics, as treated sufficiently for Escherichia coli previously, drugs should aim at carbapenem-resistant acinetobacter and MRSA, as well as fungi. Drain the ETA, and search other sources of the patient if possible.
7. Recheck to adjust
Reexamination of CCUS after nearly four hours revealed no fluid responsiveness any more, massive consolidation in right lung and multiple B lines in left lung, PAOP elevated according to E/e’. PICCO reveals extremely low SVR despite high dose of norepinephrine, high EVLWI (PCCI 6.24 L/min/m2, GEDI 742 ml/m2, PPV 7 %, SVRI 522 dyn·s·cm-5·m2, EVLWI 26ml/kg). Adjustment: fluid resuscitation should be discontinued as no responsiveness and high risk of pulmonary edema. Blood culture reports carbapenem-resistant Acinetobacter baumannii (CRAB) CXR showed large hyperdensity in right lung which represented consolidation (Figure 6) Final diagnosis: Hospital acquired pneumonia, septic shock.
ABG: arterial blood gases; IVC: Inferior vena cava; dIVC: distention index of Inferior vena cava; RV: right ventricle; LUS: lung ultrasound score; WBC: white blood cell; PCT: procalcitonin; ETA: Endotracheal aspiration; CCUS: Critical care ultrasound; MAP: mean arterial pressure; PEEP: Positive End Expiratory Pressure; ECMO: extracorporeal membrane oxygenation; MRSA: Methicillin-resistant Staphylococcus aureus; PAOP: pulmonary artery occlusion pressure; E/e’: early diastolic transmitral velocity to early mitral annulus diastolic velocity ratio; SVR: systemic vascular resistance; EVLWI: extra-vascular lung water index; PCCI: pulse contour cardio output index; GEDI: Global End-Diastolic volume Index; PPV: pulse pressure variation; SVRI: systemic vascular resistance index; CRAB: carbapenem-resistant Acinetobacter baumannii.
