Acid-Base Disorders in Patients with Chronic Obstructive Pulmonary Disease: A Pathophysiological Review

Bruno, Cosimo Marcello; Valenti, Maria-Paula

doi:10.1155/2012/915150

Cited by 66 publications

(61 citation statements)

References 51 publications

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“…We could not find a difference in splanchnic extraction between COPD patients with or without supplemental oxygen (data not shown). Another factor that supports involvement of the gut, is the presence of metabolic acidosis in COPD due to the development of stable hypercapnia [35]. Metabolic acidosis is a process known to reduce protein turnover in the splanchnic area [36].…”

Section: Discussionmentioning

confidence: 99%

Effectiveness of essential amino acid supplementation in stimulating whole body net protein anabolism is comparable between COPD patients and healthy older adults

et al. 2017

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Background The development of effective nutritional strategies in support of muscle growth for patients with chronic obstructive pulmonary disease (COPD) remains challenging. Dietary essential amino acids (EAAs) are the main driver of postprandial net protein anabolism. In agreement, EAA supplements in healthy older adults are more effective than supplements with the composition of complete proteins. In patients with COPD it is still unknown whether complete protein supplements can be substituted with only EAAs, and whether they are as effective as in healthy older adults. Methods According to a double-blind randomized crossover design, we examined in 23 patients with moderate to very severe COPD (age: 65 ± 2 y, FEV1: 40 ± 2% of predicted) and 19 healthy age-matched subjects (age: 64 ± 2 y), whether a free EAA mixture with a high proportion (40%) of leucine (EAA mixture) stimulated whole body net protein gain more than a similar mixture of balanced free EAAs and non-EAAs as present in whey protein (TAA mixture). Whole body net protein gain and splanchnic extraction of phenylalanine (PHE) were assessed by continuous IV infusion of L-[ring-2H5]-PHE and L-[ring-2H2]-tyrosine, and enteral intake of L-[15N]-PHE (added to the mixtures). Results Besides an excellent positive linear relationship between PHE intake and net protein gain in both groups (r=0.84–0.91, P<0.001), net protein gain was 42% higher in healthy controls and 49% higher in COPD patients after intake of the EAA mixture compared to the TAA mixture (P<0.0001). These findings could not be attributed to the high LEU content, as in both groups net protein gain per gram EAA intake was lower for the EAA mixture (P<0.0001). Net protein gain was higher in COPD patients for both mixtures due to a 40% lower splanchnic extraction (P<0.0001), but was similarly related to dietary PHE (i.e. EAA) plasma appearance. Conclusions In COPD patients, similarly to healthy older adults, free EAA supplements stimulate whole body protein anabolism more than free amino acid supplements with the composition of complete proteins. Therefore, free EAA supplements may aid in the prevention and treatment of muscle wasting in this patient population. Trial registry ClinicalTrials.gov; Nos.: NCT01173354 and NCT01172314; URL: www.clinicaltrials.gov

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Section: Discussionmentioning

confidence: 99%

Effectiveness of essential amino acid supplementation in stimulating whole body net protein anabolism is comparable between COPD patients and healthy older adults

et al. 2017

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“…Our novel index may also have utility in assessing renal acid-base compensations in clinical context where respiratory acidosis (e.g. chronic obstructive pulmonary disease) (Bruno & Valenti, 2012) or alkalosis (e.g. congestive heart failure) (Milionis et al 2002) is present.…”

Section: Potential Significance Applications and Future Directionsmentioning

confidence: 99%

Renal reactivity: acid‐base compensation during incremental ascent to high altitude

Zouboules

Lafave

O’Halloran

et al. 2018

The Journal of Physiology

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Key points Ascent to high altitude imposes an acid‐base challenge in which renal compensation is integral for maintaining pH homeostasis, facilitating acclimatization and helping prevent mountain sicknesses. The time‐course and extent of plasticity of this important renal response during incremental ascent to altitude is unclear. We created a novel index that accurately quantifies renal acid‐base compensation, which may have laboratory, fieldwork and clinical applications. Using this index, we found that renal compensation increased and plateaued after 5 days of incremental altitude exposure, suggesting plasticity in renal acid‐base compensation mechanisms. The time‐course and extent of plasticity in renal responsiveness may predict severity of altitude illness or acclimatization at higher or more prolonged stays at altitude. Abstract Ascent to high altitude, and the associated hypoxic ventilatory response, imposes an acid‐base challenge, namely chronic hypocapnia and respiratory alkalosis. The kidneys impart a relative compensatory metabolic acidosis through the elimination of bicarbonate (HCO3−) in urine. The time‐course and extent of plasticity of the renal response during incremental ascent is unclear. We developed an index of renal reactivity (RR), indexing the relative change in arterial bicarbonate concentration ([HCO3−]a) (i.e. renal response) against the relative change in arterial pressure of CO2 (P aC O2) (i.e. renal stimulus) during incremental ascent to altitude (Δ[ HC normalO3−]normala/ΔP aC normalO2). We aimed to assess whether: (i) RR magnitude was inversely correlated with relative changes in arterial pH (ΔpHa) with ascent and (ii) RR increased over time and altitude exposure (i.e. plasticity). During ascent to 5160 m over 10 days in the Nepal Himalaya, arterial blood was drawn from the radial artery for measurement of blood gas/acid‐base variables in lowlanders at 1045/1400 m and after 1 night of sleep at 3440 m (day 3), 3820 m (day 5), 4240 m (day 7) and 5160 m (day 10) during ascent. At 3820 m and higher, RR significantly increased and plateaued compared to 3440 m (P < 0.04), suggesting plasticity in renal acid‐base compensations. At all altitudes, we observed a strong negative correlation (r ≤ −0.71; P < 0.001) between RR and ΔpHa from baseline. Renal compensation plateaued after 5 days of altitude exposure, despite subsequent exposure to higher altitudes. The time‐course, extent of plasticity and plateau in renal responsiveness may predict severity of altitude illness or acclimatization at higher or more prolonged stays at altitude.

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“…, Guérin et al . , Bruno and Valentini ). In humans exposed to acute hypercarbia, respiratory acidosis is characterized by changes in

{HCO}_{3}^{-}

of usually <1 mEq/L per 10 mm Hg rise in P CO2 (see Table for example).…”

Section: Discussionmentioning

confidence: 94%

“…It is also worthwhile to consider the pH and HCO À 3 responses to elevations in P CO2 in sea lions and other marine mammals in relation to those seen in acute respiratory acidosis vs. compensated chronic respiratory acidosis in humans (Brackett et al 1965, Gu erin et al 2010, Bruno and Valentini 2012. In humans exposed to acute hypercarbia, respiratory acidosis is characterized by changes in HCO À 3 of usually <1 mEq/L per 10 mm Hg rise in P CO2 (see Table 2 for example).…”

Section: Discussionmentioning

confidence: 99%

Effects of inhalational anesthesia on blood gases and pH in California sea lions

Ponganis

McDonald

Tift

et al. 2017

Marine Mammal Science

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Despite the widespread use of inhalational anesthesia with spontaneous ventilation in many studies of otariid pinnipeds, the effects and risks of anesthetic‐induced respiratory depression on blood gas and pH regulation are unknown in these animals. During such anesthesia in California sea lions (Zalophus californianus), blood gas and pH analyses of opportunistic blood samples revealed routine hypercarbia (highest PCO2 = 128 mm Hg [17.1 kPa]), but adequate arterial oxygenation (PO2 > 100 mm Hg [13.3 kPa] on 100% inspiratory oxygen). Respiratory acidosis (lowest pH = 7.05) was limited by the increased buffering capacity of sea lion blood. A markedly widened alveolar‐to‐arterial PO2 difference was indicative of atelectasis and ventilation‐perfusion mismatch in the lung secondary to hypoventilation during anesthesia. Despite the generally safe track record of this anesthetic regimen in the past, these findings demonstrate the value of high inspiratory O2 concentrations and the necessity of constant vigilance and caution. In order to avoid hypoxemia, we emphasize the importance of late extubation or at least maintenance of mask ventilation on O2 until anesthetic‐induced respiratory depression is resolved. In this regard, whether for planned or emergency application, we also describe a simple, easily employed intubation technique with the Casper “zalophoscope” for sea lions.

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Acid-Base Disorders in Patients with Chronic Obstructive Pulmonary Disease: A Pathophysiological Review

Cited by 66 publications

References 51 publications

Effectiveness of essential amino acid supplementation in stimulating whole body net protein anabolism is comparable between COPD patients and healthy older adults

Effectiveness of essential amino acid supplementation in stimulating whole body net protein anabolism is comparable between COPD patients and healthy older adults

Renal reactivity: acid‐base compensation during incremental ascent to high altitude

Effects of inhalational anesthesia on blood gases and pH in California sea lions

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