Acute compartment syndrome (ACS) of the lower leg is a time-sensitive orthopedic emergency that relies heavily on precise clinical findings. Late findings of ACS can lead to limb amputation, contractures, paralysis, multiorgan failure, and death. Hallmark symptoms of ACS include the 6 P’s: pain, poikilothermia, pallor, paresthesia, pulselessness, and paralysis. Suspicion of ACS is confirmed by measurement of intracompartmental pressure of the affected compartment. The definitive treatment of ACS is timely fasciotomy. We review the pathophysiology, common causes, diagnosis, and treatment of this potentially devastating condition.
In eight healthy men a 20-min load of 1.5 W/kg body weight on a bicycle ergometer led to a significant increase of alanine and decline of leucine. Exhausting exercise caused in the same subjects a highly significant increase of alanine and decline of isoleucine, threonine, ornithine, leucine, serine, glycine, and asparasine and glutamine. The methionine and citrulline level declines also significantly. The total amino acids practically did not change. Physical exercise led furthermore to a marked increase of serum ammonia and uric acid. Urea nitrogen changed only little and on average had rather a declining tendency. The rise of alanine suggests the existence of a glucose-alanine cycle, the drop of ornithine and citrulline is most probably associated with the inhibition of ureogenesis in the liver. The reduction of leucine and isoleucine is probably the result of the entry of these amino acids into muscle and their deamination.
Obstructive sleep apnea (OSA) is highly prevalent in patients undergoing total joint arthroplasty (TJA) and is a major risk factor for postoperative cardiovascular complications and death. Recognizing this, the American Society of Anesthesiologists urges clinicians to implement special considerations in the perioperative care of OSA patients. However, as the volume of patients presenting for TJA increases, resources to implement these recommendations are limited. This necessitates mechanisms to efficiently risk stratify patients having OSA who may be susceptible to post-TJA cardiovascular complications. We explore the role of perioperative measurement of cardiac troponins (cTns) and brain natriuretic peptides (BNPs) in helping determine which OSA patients are at increased risk for post-TJA cardiovascular-related morbidity.
In nine patients with ischemic heart disease the authors investigated the arterio-coronary venous difference of free amino acids in serum at rest and during pacing. At rest aspartate was the only amino acid with a marked positive arterio-coronary venous difference. At the peak of pacing, in addition to aspartate, there is a significant positive arterio-coronary venous difference in glutamate, leucine and isoleucine and a significantly negative difference in cystine-cysteine and glutamine with asparagine. When expressed in per cent of the arterial level, the negative difference in alanine is also significant. Among the mutual correlations of arterio-coronary venous differences the negative correlation between alanine and lactate is most significant, which suggests that under normal conditions pyruvate is transformed rather to alanine, while in ischemia lactate is formed from pyruvate, and released from the heart muscle. There is also a positive correlation between alanine and glutamine and between leucine, isoleucine and glutamate.On the other hand, cystine-cysteine correlates very significantly but inversely with leucine, isoleucine and glutamate.The arterio-coronary venous difference of aspartate, though significantly positive, does not correlate with any other amino acid. The arterio-coronary venous differences of ammonia and uric acid correlate inversely, whereby uric acid, contrary to ammonia, is practically not released from the heart muscle.The importance of amino acids in the energy metabolism of the myocardium is not decisive from the quantitative aspect, various findings suggest, however, that amino acids play an important role in metabolic regulation and under certain conditions may become an essential substrate (8). Amino acids are linked at various sites with metabolic pathways, whereby a decisive role is played by transamination and oxidative deaminations. According to some findings it is probable that in the myocardium, similarly as in skeletal muscle, alanine is produced (9,15,24). The uptake of glutamate and release of alanine is probably associated with the necessity to
The renal clearance of 21 amino acids was investigated in 5 patients with chronic renal failure (inulin clearance ≈ 5–10ml/min) during the 6-week administration of a low-protein diet. The results were compared with values obtained in 6 volunteers. The renal clearance of all investigated amino acids (with the exception of Asp, His, Tau) did not differ significantly from healthy controls. The excretion fraction (amino acid clearance /inulin clearance 100) was in all investigated amino acids significantly higher than incontrols with the exception of Tau. The excretion fractions of Asp, Ser, Cys, Tyr, His, Thr, Tau and Gly were, on average, above 20%.The findings suggest that the fractional reabsorption of amino acids in residual nephrons is decreased.
A group of 17 patients with chronic renal impairment and a group of 11 patients surviving for 3-7 years after kidney transplantation were examined. In all patients plasma amino acids were analyzed. The ratio of essential/nonessential amino acids, the valine/glycine ratio and Whitehead’s quotient are influenced above all by the dietary protein intake. Raised citrulline and 3-methylhistidine values were not influenced by the protein intake, while they correlate with indicators of renal function. Changes detected after kidney transplantation are analogous.
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