The present data suggested that ultrasound-guided cannulation of the subclavian vein in critical care patients is superior to the landmark method and should be the method of choice in these patients.
Our findings suggest that LV diastolic dysfunction is significantly associated with weaning outcome in critically ill patients with preserved LV systolic function. An E/E m ratio greater than 7.8 may identify patients at high risk of weaning failure.
Although it has long been recognized that thyroid hormone is an effective positive inotrope, its efficacy in supporting hemodynamics in the acute setting of ischaemia and reperfusion (R) without worsening reperfusion injury remains largely unknown. Thus, we investigated the effects of triiodothyronine (T3) on reperfusion injury in a Langendorff-perfused rat heart model of 30 min zero-flow ischaemia and 60 min of (R) with or without T3 (40 microg/l) at R, T3-R60, n = 11 and CNT-R60, n = 10, respectively. Furthermore, phosphorylated levels of intracellular kinases were measured at 5, 15 and 60 min of R. T3 markedly improved postischaemic recovery of left ventricular developed pressure (LVDP%); 56.0% (SEM, 4.4) in T3-R60 versus 38.8% (3.1) in CNT-R60, P < 0.05. Furthermore, LDH release was significantly lower in T3-R60. Apoptosis detection by fluorescent probe optical imaging showed increased fluorescent signal in CNT-R60 hearts, while the signal was hardly detectable in T3-R60 hearts. Similarly, caspase-3 activity was found to be 78.2 (8.2) in CNT-R60 vs 40.5 (7.1) in T3-R60 hearts, P < 0.05. This response was associated with significantly lower levels of phospho-p38 MAPK at any time point of R. No significant changes in phospho- ERK1/2 and JNK levels were observed between groups. Phospho-Akt levels were significantly lower in T3 treated group at 5 min and no change in phospho-Akt levels were observed at 15 and 60 min between groups. In conclusion, T3 administration at reperfusion can improve postischaemic recovery of function while limiting apoptosis. This may constitute a paradigm of a positive inotropic agent with anti-apoptotic action suitable for supporting hemodynamics in the clinical setting of ischaemia-reperfusion.
Ultrasound-guided injection directly caudally from the inferior foramina of the adductor canal, between the sartorius muscle and the femoral artery, seems to be an effective approach for saphenous nerve block.
High anatomic variability in the obturator nerve's divisions and subdivisions does exist, and explains the difficulty frequently encountered in the application of regional anesthetic techniques.
There is accumulating evidence that thyroid hormone metabolism is altered after myocardial infarction (AMI) but its physiological relevance remains largely unknown. The present study investigated the possible role of thyroid hormone signaling in the response of the post-infarcted heart to ischaemia-reperfusion. Wistar rats were subjected to left coronary artery ligation (AMI), or sham operation (SHAM). After 8 weeks, hearts from AMI and SHAM rats were perfused in Langendorff mode and subjected to 20 min of zero-flow global ischaemia (I) and 45 min of reperfusion (R); AMI(I/R), n = 7 and SHAM(I/R), n = 7. Basal left ventricular pressure (LVDP), +dp/dt, and -dp/dt were significantly reduced. Left ventricular weight of the viable myocardium was increased by 14% in the AMI as compared to SHAM hearts, P < 0.05. T(3) and T(4) plasma levels in nM were 1.83 (0.08) and 53.3 (2.9) for SHAM and 1.76 (0.06) and 59.4 (5.2) for AMI rats, respectively, P > 0.05. TRalpha1 and TRbeta1 expression levels were 1.3- and 1.8-fold less in AMI than in SHAM hearts, P < 0.05. Furthermore, SERCA and NHE1 expression levels were 2.1- and 1.8-fold less in AMI than in SHAM, P < 0.05. PKCepsilon was 1.35-fold more in AMI compared to SHAM, P < 0.05. Myocardial glycogen content (in micromol/g) was 7.8 (1.2) in AMI as compared to 4.4 (0.5) for SHAM hearts, P < 0.05. After I/R, left ventricular end-diastolic pressure at 45 min of R (LVEDP45 in mmHg) was 20.3 (3.2) for AMI(I/R) vs 50.6 (4.8) mmHg for SHAM(I/R), P < 0.05. LDH release per gram of tissue was 251 (103) for AMI(I/R) and 762 (74) for SHAM(I/R), P < 0.05. In conclusion, TRalpha1 and TRbeta1 are downregulated after myocardial infarction and this was associated with altered expression of thyroid hormone responsive genes and increased tolerance of the post-infarcted heart to ischaemia-reperfusion injury.
We have previously shown that acute thyroid hormone treatment could limit reperfusion injury and increase post-ischemic recovery of function. In the present study, we further explore potential initiating mechanisms of this response. Thus, isolated rat hearts were subjected to 30 min zero-flow global ischemia (I) followed by 60-min reperfusion (R). Reperfusion injury was assessed by post-ischemic recovery of left ventricular developed pressure (LVDP%) and LDH release. T3 at a dose of 60 nM which had no effect on contractile function of non-ischemic myocardium, significantly increased LVDP% [48% (2.9) vs. 30.2% (3.3) for untreated group, P < 0.05] and reduced LDH release [8.3 (0.3) vs. 10 (0.42) for untreated group, P < 0.05] when administered at R. T4 (60 and 400 nM) had no effect on contractile function either in non-ischemic or ischemic myocardium. Administration of debutyl-dronedarone (DBD), a TRα1 antagonist abolished the T3-limiting effect on reperfusion injury: Thus, co-administration of T3 and DBD resulted in significantly lower LVDP%, [23% (4.7) vs. 48% (2.9) for T3 group, P < 0.05] and higher LDH release [9.9 (0.3) vs. 8.3 (0.3), for T3 group, P < 0.05]. In conclusion, acute T3 and not T4 treatment will be able to protect against reperfusion injury. T3 can exert this beneficial effect on ischemic myocardium at a dose that has no effects on non-ischemic myocardium. Acute T3-limiting effect on reperfusion injury is mediated, at least in part, via TRα1 receptor.
Hyperthyroid hearts are shown to display a phenotype of cardioprotection against ischemic stress, but the underlying signaling mechanisms remain largely unknown. The present study investigated the possible relation of HSP70 to the thyroid hormone induced cardioprotection. HSP70 is a redox-regulated molecular chaperone, and enhances cell survival under stress. Thyroxin (25 microg/100 g body weight) was administered to Wistar male rats for four days (THYR-4d) and two weeks (THYR-14d), respectively, while untreated animals served as controls (CON-4d, CON-14d). Isolated hearts from control and thyroxin treated rats were subjected to 20 min zero-flow ischemia followed by 45 min of reperfusion (I/R). The amount of HSP70 in the myocardium for THYR-14d was 1.85 times the levels of CON-14d (p < 0.05). The levels of HSP70 expression were no different between THYR-4d and CON-4d, p > 0.05. This was only accompanied by an increase in MDA levels (used as an index of oxidative stress) in THYR-14d compared to untreated hearts. These changes corresponded to a differential response of the heart to I/R; post-ischemic recovery of function was significantly increased in THYR-14d compared to CON-14d, and was no different between the THYR-4d and CON-4d hearts. In conclusion, long-term thyroxin administration results in increased tolerance of the myocardium to I/R and enhances the expression of HSP70 which may, at least in part, account for this response.
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