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Assessing Skeletal Muscle Variations in Microvascular Pressure and Unstressed Blood Volume at the Bedside
No full textObjective: Quantitative NIRS measurements for MBV partitioning inside microvessels are of current physiologic and clinical interest. In this study, in healthy subjects, we sought new bedside NIRS variables for noninvasively measuring Vu and Pi changes.
Methods: Fifteen healthy subjects underwent graded venous congestion for MBV measurements with NIRS and the reference technique strain-gauge plethysmography. From DMBV we calcu- lated vascular compliance, blood flow, and new NIRS variables including Vu and Pit and Pcrit.
Results: Extrapolating MBV changes to 0 yielded Pit 4.19 ` 0.5 mmHg corresponding to a Vu of 2.53 ` 0.43 mL/ 100 mL T. The slope for MBV began steeper at values below 18 mmHg (Pcrit). Microvascular compliance measured with NIRS or with strain gauge gave matching results. The change in MBV depended on the oxyhemoglobin increase. No correlation was found between Vu and microvascular compliance or the overall DMBV. Cumulative pressure steps showed higher linearity in DMBV than that induced by discontinuous steps.
Conclusions: The new NIRS variables we report could be a practical bench-to-bedside tool to assess venous driving pressure for systemic perfusion and measure changes in Vu within the microvascular bed
L’esmololo nel controllo della risposta emodinamica all'intubazione tracheale in anestesia orl
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Effects of passive leg raising on microvascular venous compartment in critically ill patients
No full textBACKGROUND:
Even though fluid loading is thought to improve organ perfusion, the way in which it does so remains unclear. We assessed how the microvascular bed in skeletal muscle reacts to passive leg raising in patients with and without sepsis or septic shock.
METHODS:
We studied 40 critically ill patients (group A) and 30 healthy controls (group B). The forearm microvascular bed was assessed using near-infrared spectroscopy before and after passive leg raising. We measured stressed and unstressed volumes, inside pressures, blood flow, microvascular compliance and tone.
RESULTS:
In group A, passive leg raising induced a microvascular bed increase from 4.9 (3.2-6.5) mL/100 mL tissue to 5.7 (3.9-8.1) mL/100 mL tissue (P=0.005), leaving inside pressures unchanged, whereas in group B neither volumes nor pressures changed. Patients without sepsis showed an increase in the stressed volume from 0.22 (0.10-0.28) mL/100 mL tissue to 0.34 (0.23-0.66) mL/100 mL tissue (P=0.039) and a decrease in compliance (P=0.004), whereas, in septic shock, the unstressed volume increased from 4.20 (3.01-5.82) mL/100 mL tissue to 5.32 (4.01-11.50) mL/100 mL tissue (P=0.036). In critically ill patients near-infrared spectroscopy showed no difference in microvascular variables between responders and non-responders to passive leg raising, but responders showed a cardiovascular response shorter than healthy subjects.
CONCLUSIONS:
Our study provides evidence that macrocirculatory parameters are unreliable to derive measurements of stressed and unstressed volumes. Our results indicate that in septic shock, the enlargement of the unstressed volume associated with passive leg raising induces loss of fluids to the interstitium, thus leaving organ perfusion unchanged or worse
Improving postoperative pain management after video-assisted thoracic surgery lung resection contributes to enhanced recovery, but guidelines are still lacking
No full textThoracic surgery, postthoracotomy pain, VAT
Tetraplegia following parathyroidectomy in two long-term haemodialysis patients
No full textWe report two cases of postoperative iatrogenic tetraparesis, which occurred in different hospitals after surgery for parathyroidectomy. Both patients were on long-term haemodialysis. The prolonged neck extension usually required by this procedure was probably the main factor involved in the genesis of the spinal cord injury. Spinal abnormalities associated with chronic renal failure may have made these patients more vulnerable. In our opinion, it is advisable to investigate thoroughly any sign of spinal stenosis in patients who undergo any procedure requiring significant neck extension, particularly if on long-term haemodialysis. PMID: 19686487 [PubMed - indexed for MEDLINE
ONDANSETRON INHIBITS THE ANALGESIC EFFECTS OF TRAMADOL: A POSSIBLE 5HT RECEPTOR INVOLVEMENT IN ACUTE PAIN IN HUMANS.
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