Muscle Surface pH Research Articles

Effects of increased red cell mass on subclinical tissue acidosis in hyaline membrane disease.

To determine whether there are subclinical deficits in oxygen delivery in ventilated premature neonates. Ventilated premature neonates weighing less than 1500 g, who were transfused for anaemia or who were given colloids for clotting abnormalities (or oedema), were haemodynamically monitored during the first week of life. Calf muscle surface pH (pH) was measured in conjunction with peripheral limb blood flow by occlusion plethysmography. Packed red blood cell transfusions corrected a subclinical regional tissue acidosis (low tpH) without affecting arterial pH or limb blood flow. This observation also correlated with an increase in regional oxygen delivery. The data were also suggestive of a pattern of pathological, supply dependent, oxygen delivery and are similar to other observations made in adults with adult respiratory distress syndrome. Packed red blood cells increase regional oxygen delivery and tissue surface pH. In contrast, colloid infusion provided no substantial cardiovascular or metabolic benefit to these patients and should be avoided when oxygen delivery is at issue and when there may be leaky pulmonary capillaries.

Alfentanil and skeletal muscle circulation, oxygen consumption and P50.

The preservation of blood flow to skeletal muscles has low priority in the intact organism. If cardiovascular function is disturbed, for example by anesthetic drugs, skeletal muscle circulation diminishes or stops. Skeletal muscle surface pH (m-pH) is a sensitive indicator of muscle cell oxygenation and a fall in m-pH therefore provides an early warning of deterioration in overall cardiovascular performance. In the present study we investigated the peripheral effects of a new short-acting fentanyl derivative, alfentanil. Twelve dogs were anesthetized with a bolus injection of alfentanil 0.16 mg . kg-1 i.v. M-pH was recorded continuously, while total body oxygen consumption, oxygen transport and P50 were calculated. No changes were found. In the second part of the study, we pretreated six of the dogs with the "calcium antagonist" verapamil 0.5 mg X kg-1, while the other six dogs served as controls. After a rechallenge dose of alfentanil, we again found the peripheral perfusion sufficient to meet the oxygen demand of the muscles. Side-effects to alfentanil were a decrease in Pao2, due to an increase in pulmonary shunting of venous blood, and an increase in PaCO2. The changes in pulmonary ventilation-perfusion relationships were, however, not of a magnitude that should cause concern when alfentanil is used in normal subjects.

Continuous monitoring of interstitial fluid potassium during hemorrhagic shock in dogs.

It appears that ISFET probes can reliably and continuously monitor IF K+ in vivo for intervals of at least several hours. The consistently observed increase in IF K+ in response to hemorrhage, a phenomenon invisible systemically, suggests that such probes may provide clinically valuable information regarding perfusion related events at the cellular level during onset of and resuscitation from hypoperfusion states. Precise correlation of ISFET signal to specific cellular dysfunction awaits investigation in which muscle cell membrane potential, muscle surface pH, and postexperiment cellular histology are studied concurrently.

Inoculation of Beef Steaks with Lactobacillus Species Before Vacuum Packaging. II. Effect on Meat Quality Characteristics

Biceps femoris steaks (n = 432) were inoculated with each of four Lactobacillus sp. (atypical streptobacteria and betabacteria) at a high or low level of cell concentration, vacuum-packaged, stored for up to 35 days at 1–3 C, displayed under retail conditions for 3 days and subsequently cooked for sensory panel analysis. Although there was some evidence that use of high level, rather than low level or no, inoculation with Lactobacillus cultures resulted in the lowest muscle surface pH and the brightest muscle color, the least surface discoloration and the highest overall appearance ratings following storage for 0–35 days, there were negative effects which negated efficacy of high level inoculation. Negative effects of use of high level, rather than low level or no, inoculation with Lactobacillus cultures included the highest incidence of off-odor, the highest incidence of defects during retail display (most extensive surface discoloration, most extensive peripheral discoloration, least desirable overall appearance) and the lowest palatability (juiciness, tenderness, flavor and overall palatability) ratings. Few of the differences among steaks were statistically significant but the preponderance of evidence (largely that based on numerical differences) suggests that inoculation with the Lactobacillus cultures used in this study will not improve storage life, retail caselife or palatability of beef.

Relationship of muscle surface pH to noninvasive hemodynamic studies in arterial occlusive disease : T.F. O'Donnell, J.K. Raines and R.C. Darling, Arch. Surg., 114 (1979) 600–604

Relationship of muscle surface pH to noninvasive hemodynamic studies in arterial occlusive disease : T.F. O'Donnell, J.K. Raines and R.C. Darling, Arch. Surg., 114 (1979) 600–604

Relationship of muscle surface pH to noninvasive hemodynamic studies in arterial occlusive diseases.

To examine the possible relationship between Doppler pressures (DP) and pulse volume amplitude (PVR) with muscle surface pH (pHm), we studied 20 patients before, during, and after arterial reconstruction. The mean pHm for the claudication, rest pain, and ischemic gangrene groups differed from a control group and from each other. The pHm varied directly with DP and PVR for the 20 patients as a whole. After reconstructive surgery, improvement in pHm seemed to precede changes in DP and PVR in six patients with combined segment disease. Although pHm correlates generally with DP and PVR, it is invasive. Therefore, pHm should not be used as a routine screening test. Whereas DP and PVR may reflect the anaerobic activity of peripheral tissue, they may be less prompt than pHm in responding to acute changes in blood flow.

Cerebral surface pH changes during asphyxia, hypotension, and circulatory arrest in the dog.

A technic is described for the measurement of cerebral surface pH in acute experiments in anesthetized dogs. During asphyxia and circulatory arrest, cerebral surface pH fell promptly and more profoundly than arterial blood or muscle surface pH; during hypovolemic hypotension (30 to 50 torr) cerebral surface pH declined later and less than muscle surface pH. The cerebral surface pH reflects the pH of the cortical interstitial fluid. Since the blood brain barrier is effectively impermeable to lactate, the changes recorded in the cerebral surface pH are a useful index of cortical intracellular metabolism.

Tissue hydrogen ion concentration in ischemic muscle: Effects of gradual and acute arterial occlusion, with and without acute venous hypertension

Accurate assessment of extremity &hernia is often a prerequisite to the successful completion of complex arterial reconstructions. Muscle surface pH, reflecting the status of local tissue metabolism, offers a means for continuously monitoring limb perfusion. The present investigation was designed to evaluate muscle surface pH measurements in ischemic canine hindlimbs. These measurements, subjected to careful statistical analysis, were related to extremity blood flow, perfusion pressure, effluent blood pH, and arteriovenous oxygen differences.

表面冷却低体温下開心術における筋表面 pH の変動について

表面冷却低体温下開心術における筋表面 pH の変動について

The relationship between muscle surface pH and oxygen transport.

The relationship between muscle surface pH (pHM) and the arterial-venous oxygen content difference (AVO2D) was studied in 4 patients undergoing reconstructive arterial surgery and in 6 patients undergoing acute normovolemic hemodilution. There was a consistent inverse relation between pHM in the ischemic lower extremity and the femoral AVO2D before, during and after aortic clamping. There was also an inverse relation between AVO2D and pHM during hemodilution. These data confirm that pHM is a reliable indicator of tissue perfusion and correlates with the AVO2D.

Effects of hemorrhagic shock on the microvasculature of skeletal muscle

The relationship between arteriolar and venular dimensions and the progressive failure of the homeostatic mechanisms leading to irreversibility in hemorrhagic shock was evaluated in mammalian skeletal muscle (rat cremaster). The small distribution arterioles (diameter = 17 μm) were observed to lose their tone and vasomotion at irreversibility although at 15 min after hemorrhage they exhibited enhanced vascular activity. Slowing of flow was seen to occur in the large venules (100 μm) and late in shock in smaller venules (25 μm). Venular dilatation was adjudged to be the vascular defect associated with the onset of irreversibility. Muscle surface pH and PO 2 followed a course similar to that seen in unanesthetized subjects. The red cell aggregation seen in the venules during the low flow state was generally reversed after reinfusion of the shed blood and restoration of arterial pressure.

Muscle surface pH: comparison with cardiac output and arterial pH in the critically ill subject.

Abstract A method for measuring muscle surface pH was described by Couch et al. in 1968. 1 Filler and Das adapted this concept by miniaturization of the pH probe, thus enabling its use in pediatric patients. 2–4 Investigations from both of these groups have confirmed the surface pH of skeletal muscle as a sensitive, but indirect, indicator of peripheral muscle blood flow. The proposed mechanism for this relationship is hypothesized as follows: Increased hydrogen ion activity is a consequence of anaerobic glycolysis that results in the formation of lactic acid. Anaerobic glycolysis is presumed the result of reduced tissue perfusion. It is the purpose of this paper to correlate, under a variety of experimental shock states, peripheral muscle pH with central changes in cardiac output. Two different model systems were used. Hemorrhagic shock was produced by repeated bleeding in the dog, and endotoxin shock was initiated by the intravenous injection of gram-negative endotoxin.

Acute fluid volume requirements in infants with anterior abdominal wall defects

Abstract Fluid was administered to infants with severe anterior abdominal defects to correct a perfusion deficit detected by muscle surface pH monitoring and not recognized by conventional means of monitoring. Immediate fluid need ranged from 17 to 80 ml/kg. Even in uncomplicated cases these needs were equivalent to or greater than 25% of estimated blood volume. Accurate replacement of volume deficits that appear to be aided by muscle pH monitoring will obviate much of the uncertainty in the care of these infants.

Muscle surface pH monitoring during surface-induced hypothermia with circulatory arrest in puppies

Monitoring of muscle surface pH appears to have distinct value in the management of animals being subjected to deep hypothermia and elective circulatory arrest. It provides an early warning system to detect inadequate delivery of oxygen to the peripheral tissues. It gives a minute-to-minute assessment of tissue oxygenation and an almost immediate evaluation of the effects of any therapy that is given. The early control of acidotic problems associated with deep hypothermia and circulatory arrest appears practical when muscle surface pH is monitored along with arterial pH.

Muscle surface pH as a monitor of tissue perfusion and acid-base status

Muscle pH, arterial pH, and blood gases were measured in 21 anesthetized dogs. After an initial control period, the animals were subjected to one of the following: major arterial occlusion in the limb being monitored, sever hemorrhage, hypoxia, or hypothermia (28°C). Muscle pH fell rapidly with a decrease in muscle perfusion caused by arterial occlusion or by hemorrhage, without any significant change in arterial pH. In hypoxia, muscle pH varied directly with arterial pH. Hypothermia under anesthesia did not affect muscle pH. Since muscle surface pH appears to be a reliable index of tissue perfusion and acid-base status, continuous muscle pH monitoring should prove valuable in the management of the critically ill infant. Early clinical trials have justified this impression.

MUSCLE SURFACE pH: A NEW PARAMETER IN THE MONITORING OF THE CRITICALLY ILL CHILD

In three severely ill infants, muscle surface pH was recorded continuously with a new miniaturized pH electrode for periods up to 100 hours. The clinical findings correlate with experimental results and indicate that muscle pH is a reflection of both arterial pH and the adequacy of tissue perfusion. Since muscle pH changes often precede changes in vital signs and arterial pH, muscle pH monitoring may provide the earliest warning of a deteriorating clinical situation. Although the present clinical experience is small, the findings appear to justify further trials with this method of monitoring sick infants.

Muscle surface pH as an index of peripheral perfusion in man.

COUCH, NATHAN P. M.D.; DMOCHOWSKI, JAN R. M.D.; VAN DE WATER, JOSEPH M. M.D.; HARKEN, DWIGHT E. M.D.; MOORE, FRANCIS D. M.D. Author Information

Electrometric surface pH of skeletal muscle in hypovolemia

The measurement of skeletal muscle surface hydrogen ion activity was determined in a group of animals subjected to acute hemorrhages of 4C per cent of blood volume. After a period of two hours, reinfusion of the shed blood was performed and observation continued for two more hours. The results are compared with established indicators of tissue perfusion, including blood lactate concentration, blood pH, and arterial blood pressure. Skeletal muscle surface pH showed a steady decline throughout the hypovolemic phase of the experiment and returned to control levels after restoration of blood volume. The arterial blood lactate and blood pressure underwent lesser changes, whereas the arterial blood pH did not change significantly. The redox potential was also measured, but the results were inconclusive. These data allow the conclusion that measurement of the surface pH in skeletal muscle is a sensitive indicator of volume deficit, presumably reflecting increased anaerobiosis and lactic acidosis due to ischemia.