Performance of a capnodynamic method estimating cardiac output during respiratory failure - before and after lung recruitment.

Respiratory failure may cause hemodynamic instability with strain on the right ventricle. The capnodynamic method continuously calculates cardiac output (CO) based on effective pulmonary blood flow (COEPBF) and could provide CO monitoring complementary to mechanical ventilation during surgery and intensive care. The aim of the current study was to evaluate the ability of a revised capnodynamic method, based on short expiratory holds (COEPBFexp), to estimate CO during acute respiratory failure (LI) with high shunt fractions before and after compliance-based lung recruitment. Ten pigs were submitted to lung lavage and subsequent ventilator-induced lung injury. COEPBFexp, without any shunt correction, was compared to a reference method for CO, an ultrasonic flow probe placed around the pulmonary artery trunk (COTS) at (1) baseline in healthy lungs with PEEP 5 cmH2O (HLP5), (2) LI with PEEP 5 cmH2O (LIP5) and (3) LI after lung recruitment and PEEP adjustment (LIPadj). CO changes were enforced during LIP5 and LIPadj to estimate trending. LI resulted in changes in shunt fraction from 0.1 (0.03) to 0.36 (0.1) and restored to 0.09 (0.04) after recruitment manoeuvre. Bias (levels of agreement) and percentage error between COEPBFexp and COTS changed from 0.5 (- 0.5 to 1.5) L/min and 30% at HLP5 to - 0.6 (- 2.3 to 1.1) L/min and 39% during LIP5 and finally 1.1 (- 0.3 to 2.5) L/min and 38% at LIPadj. Concordance during CO changes improved from 87 to 100% after lung recruitment and PEEP adjustment. COEPBFexp could possibly be used for continuous CO monitoring and trending in hemodynamically unstable patients with increased shunt and after recruitment manoeuvre.

Performance of a capnodynamic method estimating effective pulmonary blood flow during transient and sustained hypercapnia.

The capnodynamic method is a minimally invasive method continuously calculating effective pulmonary blood flow (COEPBF), equivalent to cardiac output when intra pulmonary shunt flow is low. The capnodynamic equation joined with a ventilator pattern containing cyclic reoccurring expiratory holds, provides breath to breath hemodynamic monitoring in the anesthetized patient. Its performance however, might be affected by changes in the mixed venous content of carbon dioxide (CvCO2). The aim of the current study was to evaluate COEPBF during rapid measurable changes in mixed venous carbon dioxide partial pressure (PvCO2) following ischemia-reperfusion and during sustained hypercapnia in a porcine model. Sixteen pigs were submitted to either ischemia-reperfusion (n = 8) after the release of an aortic balloon inflated during 30 min or to prolonged hypercapnia (n = 8) induced by adding an instrumental dead space. Reference cardiac output (CO) was measured by an ultrasonic flow probe placed around the pulmonary artery trunk (COTS). Hemodynamic measurements were obtained at baseline, end of ischemia and during the first 5 min of reperfusion as well as during prolonged hypercapnia at high and low CO states. Ischemia-reperfusion resulted in large changes in PvCO2, hemodynamics and lactate. Bias (limits of agreement) was 0.7 (-0.4 to 1.8) L/min with a mean error of 28% at baseline. COEPBF was impaired during reperfusion but agreement was restored within 5 min. During prolonged hypercapnia, agreement remained good during changes in CO. The mean polar angle was -4.19° (-8.8° to 0.42°). Capnodynamic COEPBF is affected but recovers rapidly after transient large changes in PvCO2 and preserves good agreement and trending ability during states of prolonged hypercapnia at different levels of CO.

[Successful resuscitation of a pulseless young woman with pulmonary embolus in rural Iceland]. / Mannbjorg a Modrudal a Fjollum.

A 27 year old woman suffered a witnessed cardiac arrest in rural Iceland and regained pulse after one hour's resuscitation. She was transported by an air ambulance to a tertiary medical center in Reykjavik where she was diagnosed with a large pulmonary embolus. After 24 hours therapeutic hypothermia she was rewarmed and extubated two days later. She was discharged from the hospital after two weeks neurologically intact. This case illustrates that even in rural circumstances the chain of survival works if all the links are strong, with early access, early resuscitation and early advanced care.

[Management of patients with STEMI transported with air-ambulance to Landspitali University Hospital in Reykjavík]. / Flutningstími og gaedi medferdar hjá sjúklingum med ST-haekkunar hjartadrep á Nordur- og Austurlandi.

INTRODUCTION: A good outcome of patients presenting with STEMI (ST-Segment Elevation Myocardial Infarction) depends on early restoration of coronary blood flow. Pre-hospital fibrinolysis is recommended if primary percutaneous coronary intervention (PPCI) cannot be performed within 90 minutes of first medical contact (FMC). The purpose of this study was to study transport times for patients with STEMI who were transported with air-ambulance from the northern rural areas of Iceland to Landspitali University Hospital in Reykjavík, and to assess if the medical management was in accordance with clinical guidelines. MATERIALS AND METHODS: Retrospective chart review identified 33 patients with STEMI who were transported with air-ambulance to Landspitali University Hospital in Reykjavík during the years 2007 and 2008. RESULTS: The total time from first medical contact to arrival at Landspitali University Hospital emergency room was 3 hours and 7 minutes (median). All patients received aspirin and 26 (78.8%) received clopidogrel and enoxaparin. 16 patients (48.5%) received thrombolytic therapy in median 33 minutes after FMC and 15 patients had PPCI performed in median 4 hours and 15 minutes after FMC. Estimated PCI related delay was 3 hours and 42 minutes (median). One patient died and one was resuscitated within 30 hospital days. Mean hospital stay was 6.0 days. CONCLUSIONS: First medical contact to balloon time of less than 90 minutes is impossible for patients with STEMI transported from the northern rural areas to Landspitali University Hospital in Reykjavík. Medical therapy was in many cases suboptimal and PCI related delay too long.

Resolution of proteinuria in a patient with X-linked Alport syndrome treated with cyclosporine.

We report a 9-year-old Icelandic male with Alport syndrome and nephrotic-range proteinuria who responded well to cyclosporine therapy. He presented at the age of 2 years with gross hematuria and proteinuria during an episode of upper respiratory tract infection. Three years later he had developed persistent proteinuria; kidney function was normal. A renal biopsy revealed marked irregularities in the glomerular basement membrane consistent with Alport syndrome. Mutation analysis revealed a single base insertion in COL4A5 which was predicted to cause a major structural defect in the collagen IV alpha5 chain. Despite angiotensin-converting enzyme inhibitor therapy his proteinuria progressed to the nephrotic range associated with edema. At the age of 7 years, cyclosporine therapy was instituted, which promptly resulted in almost complete resolution of proteinuria. Three years later his urinary protein excretion was close to the normal range and serum creatinine remained within normal limits. We conclude that closely monitored cyclosporine therapy may be a safe and effective treatment in patients with severe proteinuria and Alport syndrome.