Etomidate-induced hypotension: a pathophysiological approach using arterial elastance.

INTRODUCTION: Anaesthesia frequently induces hypotension. Several recent studies have analysed arterial elastance (Ea) in order to describe clinical variations of mean arterial pressure (MAP). The objective of the study was to assess Ea to explain MAP variation following etomidate induction. METHODS: We conducted a prospective single-centre study. Inclusion criteria were patients undergoing elective cardiac surgery with invasive blood pressure monitoring. Ea was expressed as Pes/SV (Pes: end systolic pressure, SV: stroke volume). Cardiac index (CI), peripheral vascular resistance (PVR) and arterial compliance (C) was compared before and 2 minutes after etomidate induction. Arterial hypotension was defined as a decrease greater than 15% of the baseline MAP. RESULTS: Of the 45 patients included, 24 (53%) had a preserved MAP and 21 (47%) had an etomidate-induced hypotension. Ea was similar before induction and decreased in the decreased MAP group 2 minutes after induction (2.0 mmHg.ml-1 [1.7-2.4] vs 1.4 mmHg.ml-1 [0.9-1.9]; p = 0.001). Arterial compliance (C) increased in the decreased MAP group 2 minutes after induction (0.8 ml. mmHg-1 [0.6-1.0] vs 0.5 ml. mmHg-1 [0.4-0.6], p < 0.0001). No significant change in CI or PVR was observed between patients with or without etomidate-induced hypotension. CONCLUSION: Etomidate-induced hypotension was associated to a decrease in Ea. Ea variations can mainly be explained by induced changes in arterial compliance.

The presence of elastic compression stockings reduces the fluid responsiveness of patients in the operating room.

BACKGROUND: The aim of this study was to investigate whether elastic compression stockings (ECS) can affect fluid responsiveness parameters before and during passive leg raising (PLR) maneuvers. METHODS: In the operating room (OR), we performed a prospective study including patients referred for cardiac surgery. Blood pressure (BP), ΔPP, heart rate (HR), central venous pressure (CVP), stroke volume (SV) and aortic blood flow (ABF) (by esophageal doppler) were measured according to four conditions: supine position without ECS (baseline 1), lower limbs raised to an angle of 45° (PLR 1), returned to the supine position with ECS (baseline 2), then a second PLR maneuver with ECS was performed (PLR 2). RESULTS: Twenty patients were included. BP, SV, ABF and CVP increased significantly. ΔPP and HR decreased during PLR 1. At baseline 2, HR and ΔPP decreased significantly compared to baseline 1. During PLR 2, increase of SV (4% [9]) and ABF (4% [9]), and the decrease of ΔPP (-19% [104]) were significantly lower than those observed at PLR 1 (7% [21] P=0.05; 9% [8] P=0.02 and -66% [40] P=0.02, respectively). Eleven patients presented a ΔPP≥13% at baseline 1. Only 1 patient still presented a ΔPP≥13% with ECS at baseline 2. Only 3/9 patients with an increase of ABF ≥10% and 2/11 patients with an increase of PP ≥12% during the PLR 1 presented similar results during PLR 2. CONCLUSIONS: In the OR, ECS provoke a self-fluid loading increasing ABF, decreasing ΔPP and PLR response. The presence of ECS should be considered when managing hemodynamic parameters of patients.

Association Between End-Tidal Carbon Dioxide Pressure and Cardiac Output During Fluid Expansion in Operative Patients Depend on the Change of Oxygen Extraction.

In a model of hemorrhagic shock, end-tidal carbon dioxide tension (EtCO2) has been shown to reflect the dependence of oxygen delivery (DO2) and oxygen consumption (VO2) at the onset of shock. The objectives of the present study were to determine whether variations in EtCO2 during volume expansion (VE) are correlated with changes in oxygen extraction (O2ER) and whether EtCO2 has predictive value in this respect.All patients undergoing cardiac surgery admitted to intensive care unit in whom the physician decided to perform VE were included. EtCO2, cardiac output (CO), blood gas levels, and mean arterial pressure (MAP) were measured before and after VE with 500 mL of lactated Ringer solution. DO2, VO2, and O2ER were calculated from the central arterial and venous blood gas parameters. EtCO2 responders were defined as patients with more than a 4% increase in EtCO2 after VE. A receiver-operating characteristic curve was established for EtCO2, with a view to predicting a variation of more than 10% in O2ER.Twenty-two (43%) of the 51 included patients were EtCO2 responders. In EtCO2 nonresponders, VE increased MAP and CO. In EtCO2 responders, VE increased MAP, CO, EtCO2, and decreased O2ER. Changes in EtCO2 were correlated with changes in CO and O2ER during VE (P < 0.05). The variation of EtCO2 during VE predicted a decrease of over 10% in O2ER (area under the curve [95% confidence interval]: 0.88 [0.77-0.96]; P < 0.0001).During VE, an increase in EtCO2 did not systematically reflect an increase in CO. Only patients with a high O2ER (i.e., low ScvO2 values) display an increase in EtCO2. EtCO2 changes during fluid challenge predict changes in O2ER.

Fatal multifocal Pasteurella multocida infection: a case report.

BACKGROUND: In humans, Pasteurella multocida infections are usually limited to the soft tissues surrounding a lesion. However, P. multocida can also cause systemic infections (such as pneumonia, lung abscess, peritonitis, endocarditis, meningitis and sepsis)-especially in patients with other underlying medical conditions. CASE PRESENTATION: We report on a case of fulminant P. multocida bacteremia at several sites (soft tissues, endocarditis and joints) on a white European man. Despite surgery and intensive medical care, the patient died. CONCLUSIONS: The present case emphasizes the importance of appropriate initial treatment of skin wounds. Patients at risk should be aware of the possible consequences of being bitten, scratched or licked by their pet.