Hypocapnia in women with fibromyalgia.

OBJECTIVES: The purpose of this study was to investigate whether people with fibromyalgia (FM) have dysfunctional breathing by examining acid-base balance and comparing it with healthy controls. METHODS: Thirty-six women diagnosed with FM and 36 healthy controls matched for age and gender participated in this cross-sectional study. To evaluate acid-base balance, arterial blood was sampled from the radial artery. Carbon dioxide, oxygen, bicarbonate, base excess, pH and lactate were analysed for between-group differences. Blood gas analyses were performed stepwise on each individual to detect acid-base disturbance, which was categorized as primary respiratory and possible compensation indicating chronicity. A three-step approach was employed to evaluate pH, carbon dioxide and bicarbonate in this order. RESULTS: Women with FM had significantly lower carbon dioxide pressure (p = 0.013) and higher lactate (p = 0.038) compared to healthy controls at the group level. There were no significant differences in oxygen pressure, bicarbonate, pH and base excess. Employing a three-step acid-base analysis, 11 individuals in the FM group had a possible renally compensated mild chronic hyperventilation, compared to only 4 among the healthy controls (p = 0.042). CONCLUSIONS: In this study, we could identify a subgroup of individuals with FM who may be characterized as mild chronic hyperventilators. The results might point to a plausible dysfunctional breathing in some women with FM.

Perioperative Evaluation of Arterial and Venous Whole Blood in the Lamb (Ovis aries) Fontan Model.

Whole blood analysis can evaluate numerous parameters, including pH, pCO2, pO2, HCO3 - , base excess, glucose, electrolytes, lactate, blood urea nitrogen, creatinine, bilirubin, and hemoglobin. This valuable tool enables clinicians to make more informed decisions about patient care. However, the current body of literature describing perioperative whole blood analysis in Dorset sheep (Ovis aries) is small, so clinicians lack adequate information to guide their decision-making when evaluating test results. We evaluated arterial and venous whole blood pH, bicarbonate, pCO2, lactate, creatinine, and blood urea nitrogen before and for the first 24 hours after surgery in 2 cohorts of male and female Ovis arie s undergoing one of 2 major cardiovascular procedures, a Single-Stage Fontan or an inferior vena cava to pulmonary artery extracardiac conduit implantation (IP-ECC). The cohort undergoing a Single-Stage Fontan, which is the more complex procedure, exhibited greater deviation from baseline measurements than did the cohort undergoing the IP-ECC for lactate, bicarbonate, and creatinine. The cohort undergoing the IP-ECC showed no significant deviation from baseline for any parameters, potentially indicating a better safety margin than expected when compared with the Single-Stage Fontan. Together, these results indicate the clinical value of arterial and venous whole blood measurements in perioperative management of sheep and can provide a reference for clinicians managing sheep after significant cardiovascular procedures.

Evaluating the Risk of Irreversible Intestinal Necrosis Among Critically Ill Patients With Nonocclusive Mesenteric Ischemia.

INTRODUCTION: To identify factors associated with irreversible transmural necrosis (ITN) among critically ill patients experiencing nonocclusive mesenteric ischemia (NOMI) and to compare the predictive value regarding ITN risk stratification with that of the previously described Clichy score. METHODS: All consecutive patients admitted to the intensive care unit between 2009 and 2019 who underwent exploratory laparotomy for NOMI and who had an available contrast-enhanced computed tomography with at least 1 portal venous phase were evaluated for inclusion. Clinical, laboratory, and radiological variables were collected. ITN was assessed on pathological reports of surgical specimens and/or on laparotomy findings in cases of open-close surgery. Factors associated with ITN were identified by univariate and multivariate analysis to derive a NOMI-ITN score. This score was further compared with the Clichy score. RESULTS: We identified 4 factors associated with ITN in the context of NOMI: absence of bowel enhancement, bowel thinning, plasma bicarbonate concentration ≤15 mmol/L, and prothrombin rate <40%. These factors were included in a new NOMI-ITN score, with 1 point attributed for each variable. ITN was observed in 6%, 38%, 65%, 88%, and 100% of patients with NOMI-ITN score ranging from 0 to 4, respectively. The NOMI-ITN score outperformed the Clichy score for the prediction of ITN (area under the receiver operating characteristics curve 0.882 [95% confidence interval 0.826-0.938] vs 0.674 [95% confidence interval 0.582-0.766], respectively, P < 0.001). DISCUSSION: We propose a new 4-point score aimed at stratifying risk of ITN in patients with NOMI. The Clichy score should be applied to patients with occlusive acute mesenteric ischemia only.

Increasing Tumor Extracellular pH by an Oral Alkalinizing Agent Improves Antitumor Responses of Anti-PD-1 Antibody: Implication of Relationships between Serum Bicarbonate Concentrations, Urinary pH, and Therapeutic Outcomes.

Acidic extracellular pH (pHe) is characteristic of the tumor microenvironment. Several reports suggest that increasing pHe improves the response of immune checkpoint inhibitors in murine models. To increase pHe, either sodium bicarbonate (NaHCO3) or citric acid/potassium-sodium citrate (KNa-cit) was chronically administered to mice. It is hypothesized that bicarbonate ions (HCO3-), produced from these alkalinizing agents in vivo, increased pHe in the tumor, and excess HCO3- eliminated into urine increased urinary pH values. However, there is little published information on the effect of changing serum HCO3- concentrations, urinary HCO3- concentrations and urinary pH values on the therapeutic outcomes of immunotherapy. In this study, we report that oral administration of either NaHCO3 or KNa-cit increased responses to anti-programmed cell death-1 (PD-1) antibody, an immune checkpoint inhibitor, in a murine B16 melanoma model. In addition, we report that daily oral administration of an alkalinizing agent increased blood HCO3- concentrations, corresponding to increasing the tumor pHe. Serum HCO3- concentrations also correlated with urinary HCO3- concentrations and urinary pH values. There was a clear relationship between urinary pH values and the antitumor effects of immunotherapy with anti-PD-1 antibody. Our results imply that blood HCO3- concentrations, corresponding to tumor pHe and urinary pH values, may be important factors that predict the clinical outcomes of an immunotherapeutic agent, when combined with alkalinizing agents such as NaHCO3 and KNa-cit.

Sex Differences of Kidney Stone Urine Risk Factors after Roux-en-Y Gastric Bypass.

INTRODUCTION: Roux-en-Y gastric bypass (RYGB) is a bariatric surgical procedure that is associated with higher risk of kidney stones after surgery. We examined urine composition in 18 men and women before and after RYGB to examine differences in kidney stone risk. METHODS: Three 24-h urine collections were performed before and 1 year after RYGB. We analyzed mean urinary values for pre- and post-RYGB collections and compared men and women. RESULTS: Seven men and eleven women completed pre- and post-RYGB urine collections. Pre-RYGB, men had higher calcium oxalate supersaturation (CaOx SS) (7.0 vs. 5.0, p = 0.04) compared with women. Post-RYGB, women had higher urine CaOx SS (13.1 vs. 4.6, p = 0.002), calcium phosphate supersaturation (1.04 vs. 0.59, p = 0.05), and lower urine volumes (1.7 vs. 2.7L, p < 0.001) compared with men. DISCUSSION/CONCLUSION: There are important differences in urine composition by sex that may contribute to higher kidney stone risk in women after RYGB compared with men.

False-negative diagnosis of high anion gap in patients with end-stage kidney disease.

The traditional anion gap (AG) equation is widely used, but its misdiagnosis in end-stage kidney disease (ESKD) patients has not been investigated fully. Diagnostic accuracy to detect high AG was cross-sectionally evaluated using 3 AG equations in 1733 ESKD patients with an eGFR less than 15 mL/min/1.73 m2. The prevalence of high AG was 67.9%, 92.1% and 97.4% by the traditional, albumin-adjusted AG (aAG) and full AG equations, respectively. The sensitivity, specificity, accuracy and Kappa coefficient obtained with the traditional AG vs aAG equation were 0.70 vs 0.94, 0.98 vs 0.93, 0.7 vs 0.94, and 0.103 vs 0.44, respectively. Next, we created a subcohort comprising only patients with high full AG and investigated how the traditional AG equation leads to misdiagnoses. Multivariable-adjusted regression analysis in 1688 patients revealed that independent factors associated with a false-negative AG diagnosis were ARB use, eGFR, blood leukocyte count, serum chloride, bicarbonate, ionized calcium, potassium, albumin and phosphate. 93.2% of our subcohort prescribed any of RAAS inhibitors, Loop diuretics or Alkali which could increase either serum chloride or bicarbonate. Frequent use of these possible AG-reducing medications may conceal high AG state in patients with ESKD unless they have incidental inflammation which may increase AG value.

Low Preoperative Lung Functions in Children With Early Onset Scoliosis Predict Postoperative Length of Stay.

INTRODUCTION: Children with early onset scoliosis (EOS) undergoing spine surgery often have significant respiratory disease. Preoperative risk assessments that predict an increased length of hospital stay (LOS) for this group have not been previously evaluated. METHODS: A voluntary protocol using preoperative lung function studies began among participants of a multicenter registry in 2016. Preoperative assessments were standardized to include spirometry, blood hemoglobin levels, serum bicarbonate, albumin and prealbumin; radiographic parameters of the spine, C-EOS classification and need for preoperative pulmonary assistance before initial growth friendly device insertion or "definitive" spine fusion. Primary outcome was LOS postoperatively. Data, including age, diagnosis, and type of surgery, was collected prospectively. Secondary outcomes measured included intensive care unit LOS, requirement for new pulmonary assistance on discharge, and pulmonary complications. Groups were compared using the Fisher exact tests. RESULTS: Of 525 children enrolled, 101 (20%) had preoperative spirometry. Median age was 8.9 years [interquartile range (IQR): 4.27]. Etiologies for EOS included 29 neuromuscular (28%), 33 idiopathic (32%), 19 syndromic (19%), and 22 congenital (21%) scoliosis. Eighty (78%) had growing rod (GR) insertions; 23 (22%) had spine fusion SF. Eighteen subjects (17%) were hospitalized ≥7 days (median=9 d); 83 had a LOS <7 days (median=3 d). Percentage of forced vital capacity (FVC%) predicted was inversely associated with LOS ≥7 days with a median of 75.3% (IQR: 41.7) for LOS <7 days and 51.7% (IQR: 41.6) (P=0.02). There were no detectable differences in LOS for other preoperative values. CONCLUSION: FVC predicted ≤50% preoperatively in children undergoing initial growth friendly rod insertion or definitive fusion after growth friendly treatment is associated with an increased risk of postoperative hospital stays ≥7 days. As demonstrated in previous studies, severe restrictive lung disease (FVC% predicted at or below 50%) is associated with increased risk of poorer outcomes for EOS patients.

Metabolic Alkalosis in the Pediatric Patient: Treatment Options in the Pediatric ICU or Pediatric Cardiothoracic ICU Setting.

Metabolic alkalosis is characterized by the primary elevation of the serum bicarbonate concentration with a normal or elevated partial pressure of carbon dioxide. Although there may be several potential etiologies in the critically ill patient in the pediatric or cardiothoracic intensive care unit, metabolic alkalosis most commonly results from diuretic therapy with chloride loss. In most cases, the etiology can be determined by a review of the patient's history and medication record. Although generally innocuous with limited impact on physiologic function, metabolic alkalosis may impair central control of ventilation, especially when weaning from mechanical ventilation. The following manuscript presents the normal homeostatic mechanisms that control pH, reviews the etiology of metabolic alkalosis, and outlines the differential diagnosis. Options and alternatives for treatment including pharmacologic interventions are presented with a focus on these conditions as they pertain to the patient in the pediatric or cardiac intensive care unit.

Preoperative Screening for Obstructive Sleep Apnea Using Alternative Scoring Models of the Sleep Tiredness Observed Pressure-Body Mass Index Age Neck Circumference Gender Questionnaire: An External Validation.

BACKGROUND: The Sleep Tiredness Observed Pressure-Body mass index Age Neck circumference Gender (STOP-Bang) questionnaire is a validated preoperative screening tool for identifying patients with obstructive sleep apnea (OSA). Although it has a high sensitivity at scores ≥3, its specificity is moderate, particularly for scores of 3-4. This study aimed to externally validate the STOP-Bang questionnaire and the alternative scoring models that have been proposed to improve its predictive performance. METHODS: This prospective cohort study included 115 surgical patients with preoperative STOP-Bang scores of 3-8. Type 3 sleep recordings identified moderate-to-severe OSA, reflected by an apnea-hypopnea index (AHI) of >15. Patients were categorized into 2 subgroups: patients with an intermediate (STOP-Bang 3-4) or a high risk of OSA (STOP-Bang 5-8). For patients with scores of 3-4, we tested approaches identified in previous studies: stepwise stratification of the STOP-Bang questionnaire and additional preoperative measurement of serum bicarbonate concentrations. RESULTS: The incidence of moderate-to-severe OSA was significantly higher in patients with STOP-Bang scores of 5-8 than in patients with scores of 3-4: 45 of 58 patients (78%) versus 30 of 57 patients (53%), respectively (P < .01). For patients with STOP-Bang scores of 3-4, we found no differences regarding their OSA diagnosis between patients included in the alternative scoring models and those not included. CONCLUSIONS: The STOP-Bang questionnaire detected moderate-to-severe OSA patients when scores reached 5-8. However, its performance was altered in patients with STOP-Bang scores of 3-4, and alternative scoring models with specific combinations of factors failed to improve the screening of these patients.

Hyperchloremic acidosis develops at the stage G4 and shifts to high anion gap acidosis at the stage G5 in chronic kidney disease.

BACKGROUND: Amelioration of hyperchloremic acidosis (Cl-Ac), a common complication in chronic kidney disease (CKD), could preserve renal function in chronic kidney disease (CKD). However, the development of Cl-Ac in CKD has not been clarified yet. METHODS: The degree of Cl-Ac, which is indicated as the bicarbonate concentration decrease with serum chloride concentration increase (∆[HCO3-]Cl), was compared with the estimated glomerular filtration rate (eGFR) by using CKD patient records. RESULTS: In 307 records with metabolic acidosis, a spline curve obtained from the plot comparing ∆[HCO3-]Cl with eGFR showed that ∆[HCO3-]Cl did not change, increased, and decreased during eGFR decrease until 27, from 27 to 17.5, and from 17.5 mL/min/1.73 m2, respectively. CONCLUSION: By CKD progression, Cl-Ac progressed and regressed at the CKD stages G4 and G5, respectively. The regression would have reflected the shift of Cl-Ac to high anion gap acidosis.

A case series of distal renal tubular acidosis, Southeast Asian ovalocytosis and metabolic bone disease.

BACKGROUND: Familial distal renal tubular acidosis (dRTA) associated with mutations of solute carrier family 4 membrane - 1 (SLC4A1) gene could co-exist with red cell membrane abnormality, Southeast Asian ovalocytosis (SAO). Although this association is well described in Southeast Asian countries, it is less frequently found in Sri Lanka. CASE PRESENTATION: We describe six patients who had dRTA co-existing with SAO. All of them initially presented with severe hypokalemia and paralysis. They presented within a period of six months to the Teaching Hospital Anuradhapura, Sri Lanka. All had metabolic acidosis indicated by low serum bicarbonate. Three of them were having underlying chronic kidney disease as well. Those three patients had mixed high and normal anion gap metabolic acidosis indicated by low delta ratio. In all dRTA was confirmed by presence of normal anion gap, hyperchloraemia, high urine pH and positive urine anion gap. Examination of blood films of all of them revealed presence of stomatocytes and macro-ovalocytosis compatible with SAO. In relation to complications of dRTA, two patients had medullary nephrocalcinosis. Three patients had biochemical evidence of osteomalacia, with two of them having radiological evidence of diffuse osteosclerosis. One patient had secondary hyperparathyroidism and a pathological fracture. CONCLUSIONS: Erythrocyte in SAO is exceptionally rigid and this abnormality is said to be evolved as it protects against Plasmodium vivax malaria and cerebral malaria cause by Plasmodium falciparum. Although two families of SAO was described earlier, SAO and dRTA combination was reported only once in a patient from Anuradhapura district. Distal renal tubular acidosis, SAO combination and its related complications including nephrocalcinosis, chronic kidney disease and metabolic bone disease was not described in Sri-Lankan literature. This case series emphasize the importance of investigating recurrent/ chronic hypokalemia to diagnose dRTA and its associations, as early correction of acidosis could prevent development of chronic kidney disease and metabolic bone disease.

Respiratory problems owing to severe metabolic alkalosis in infants presenting with hypertrophic pyloric stenosis.

OBJECTIVE: Uncorrected metabolic alkalosis in infantile hypertrophic pyloric stenosis (IHPS) could lead to perioperative apnea. However, the precise incidence of preoperative respiratory problems and the association with metabolic alkalosis are unknown. Therefore, we aimed to determine the incidence of preoperative respiratory problems in IHPS and to assess the association with metabolic alkalosis. METHODS: We retrospectively reviewed all patients diagnosed with IHPS during 2007-2017. Respiratory problems were classified as present or absent. With multivariate logistic regression we analyzed the association between bicarbonate and respiratory problems, corrected for gestational age and birth weight. RESULTS: We included 459 infants, of whom 23 developed preoperative respiratory problems (5.0%). Infants with preoperative respiratory problems were more often female (43.5% vs. 13.3% p = 0.001) and had significantly higher median serum levels of bicarbonate (32.0 mmol/L vs. 30.0 mmol/L), base excess (6.5 mmol/L vs. 5.3 mmol/L) and pCO2 (6.4 kPa vs. 5.9 kPa), compared to infants without respiratory problems. Multivariate analysis of serum bicarbonate and presence of respiratory problems showed an OR of 2.18 per 10 mmol/L (95% CI 1.21-4.71) (p = 0.009). The optimal bicarbonate cutoff point was 25.7 mmol/L (sensitivity 100%, specificity 13.4%). CONCLUSION: IHPS with metabolic alkalosis potentially results in preoperative respiratory problems. A lower bicarbonate target before surgery might be recommended and respiratory monitoring should be considered. LEVEL OF EVIDENCE: Level IV.

Osteonecrosis of Femoral Head, An Overlooked Long-Term Complication after Paraquat Intoxication: A Retrospective Cohort Study.

With increasing numbers of patients surviving acute intoxication phase, long-term complication after paraquat intoxication is a topic worth exploring, such as osteonecrosis (ON) of femoral head. We reviewed 86 paraquat-intoxicated survivors between 2000 and 2012 in Chang Gung Memorial Hospital, a 3700-bed tertiary hospital in Taiwan. With all the patients underwent same detoxification protocol in the acute stage, 17.4% of paraquat poisoning survivors developed ON of femoral head requiring surgery during follow up. Most of ON episodes occurred within 2 to 4 years after paraquat intoxication and then plateau after 6 years. ON patients exhibited higher SOFA scores than non-ON patients (2.80 ± 2.14 vs. 1.76 ± 1.52, p = 0.028). Furthermore, AKIN scores are also higher in the ON patients than non-ON patients (0.87 ± 1.13 vs. 0.38 ± 0.74, p = 0.040). Multivariate logistic regression showed higher AKIN score and higher partial pressure of carbon dioxide in the blood 48 hours after admission significantly predicted ON of femoral head after paraquat intoxication (p = 0.002 and p = 0.006 respectively). Larger studies with longer follow-up durations are warranted to confirm our finding.

Interventionist videothermometry: a new model of cardiac ischemia evaluation.

BACKGROUND: The purpose of the present study was to evaluate, through videothermometry, the temperature variation in the hearts of rabbits, that underwent induced myocardial ischemia and reperfusion. RESULTS: A total of 20 female rabbits were divided into two groups: a treated group and a sham group, the treatment group underwent 5 min of cardiac arrest and reperfusion, using the inflow occlusion technique. Throughout the experiment, the animals were monitored by videothermometry, observing the thermal variations of the myocardial tissue. During the experiment, at different times, blood gas tests and tests to evaluate the lactate concentrations were performed. At the end of the experiment, each heart was submitted to histopathological evaluation. In the treated group, there was a reduction in temperature of the myocardial tissue during the circulatory arrest compared to the sham group. Additionally, a colder area next to the caudal vena cava ostium and the right atrium was observed. Notably, despite the 5 min of cardiac arrest in the treated group, both the lactate and bicarbonate levels were maintained without significant variation. However, there was an increase in PaCO2 and pH reduction, featuring respiratory acidosis. In relation to the histopathological study, the presence of hydropic degeneration in the myocardium of animals in the treated group was observed. CONCLUSIONS: Based on these results, the videothermometry was efficient in identifying the range of myocardial tissue temperature, suggesting that the first areas to suffer due to cardiac arrest were the caudal vena cava ostium and the right atrium. However, in regard to the angiographic coronary thermography, the study was not feasible due to the small size of the coronary. There was no variation between the groups regarding the presence of myocardial infarction, myocardial congestion, myocardial edema and myocardial hemorrhage.

Metformin Preconditioning Improves Hepatobiliary Function and Reduces Injury in a Rat Model of Normothermic Machine Perfusion and Orthotopic Transplantation.

BACKGROUND: Preconditioning of donor livers before organ retrieval may improve organ quality after transplantation. We investigated whether preconditioning with metformin reduces preservation injury and improves hepatobiliary function in rat donor livers during ex situ normothermic machine perfusion (NMP) and after orthotopic liver transplantation. METHODS: Lewis rats were administered metformin via oral gavage, after which a donor hepatectomy was performed followed by a standardized cold storage period of 4 hours. Graft assessment was performed using NMP via double perfusion of the hepatic artery and portal vein. In an additional experiment, rat donor livers preconditioned with metformin were stored on ice for 4 hours and transplanted to confirm postoperative liver function and survival. Data were analyzed and compared with sham-fed controls. RESULTS: Graft assessment using NMP confirmed that preconditioning significantly improved ATP production, markers for hepatobiliary function (total bile production, biliary bilirubin, and bicarbonate), and significantly lowered levels of lactate, glucose, and apoptosis. After orthotopic liver transplantation, metformin preconditioning significantly reduced transaminase levels. CONCLUSIONS: Preconditioning with metformin lowers hepatobiliary injury and improves hepatobiliary function in an in situ and ex situ model of rat donor liver transplantation.

HEALTH STATUS AND BASELINE HEMATOLOGY, BIOCHEMISTRY, AND BLOOD GAS VALUES OF GALAPAGOS SHEARWATERS (PUFFINUS SUBALARIS).

The Galápagos shearwater, Puffinus subalaris, is a seabird endemic to the Galápagos archipelago. Hematology, blood chemistry, and general health parameters have not been published for this species. Analyses were run on blood samples drawn from 20 clinically healthy Galápagos shearwaters captured by hand at their nests at Islote Pitt on San Cristóbal Island in July 2016. A portable blood analyzer (iSTAT) was used to obtain near immediate field results for pH, pO2, pCO2, TCO2, HCO3 -, hematocrit, hemoglobin, sodium, potassium, chloride, ionized calcium, creatinine, urea nitrogen, anion gap, and glucose. Blood lactate was measured using a portable Lactate Plus analyzer. The reported results provide baseline data that can be used for comparisons among populations and in detecting changes in health status among Galápagos shearwaters.

Serum bicarbonate is a marker of peri-operative mortality but is not associated with long term survival in colorectal cancer.

AIMS: Inflammation is a hallmark of cancer whose activity is modulated within the tumor microenvironment by low tumoral pH. Recent evidence in the literature has suggested a link between low serum bicarbonate, low tumoral pH and cancer related inflammation. There is however little clinical evidence in human patients regarding the prognostic role of serum bicarbonate. Therefore, the primary aim of this study was to investigate the short and long-term prognostic utility of serum bicarbonate in colorectal cancer (CRC) patients undergoing resection of their primary tumor. The study also aimed to investigate the association of serum bicarbonate with known markers of systemic inflammation. METHODS: A total of 3281 consecutive patients who underwent surgical resection of their primary CRC from January 1998 to December 2012. Of these, 2223 stage I-IV patients had available data for analysis. The association of serum bicarbonate with overall survival was assessed using univariate and multivariate cox regression analyses. The association of bicarbonate with other clinicopathological variables was assessed by chi squared and Fisher's exact tests. RESULTS: Serum bicarbonate was associated with peri-operative mortality in multivariate analysis (p<0.001). Age (p = 0.004), grade (p = 0.043), creatinine (p = 0.036) and sodium (p = 0.036) were also markers associated with peri-operative mortality. For long term survival at 5 years, bicarbonate was significantly associated with overall survival in univariate analysis (p<0.001) but was not significant in multivariate analysis (p = 0.075). In exploratory analysis, serum bicarbonate was found to be significantly associated with the lymphocyte-to-monocyte ratio (p<0.001) and neutrophil-to-lymphocyte ratio (p<0.001). CONCLUSIONS: In peri-operative colorectal cancer patients, serum bicarbonate was associated with 30-day survival but not 5-year survival.

Retrospective study of the efficacy of oral potassium supplementation in cats with kidney disease.

OBJECTIVES: The aim of this study was to assess the effect of three oral potassium supplements (potassium gluconate tablets [PGT], potassium gluconate granules [PGG] and potassium citrate granules [PCG]) on hypokalemia and serum bicarbonate in cats with chronic kidney disease (CKD). METHODS: Medical records (2006-2016) were retrospectively searched for cats that had been prescribed an oral potassium supplement for management of their CKD-associated hypokalemia. For inclusion, laboratory work had to be available at the time of hypokalemia diagnosis, and at recheck within 1-6 weeks. Treatment response was defined in three ways: any increase in potassium, an increase in potassium to within the normal reference interval, and an increase to >4 mEq/l. RESULTS: Thirty-seven cats met inclusion criteria (16 PGT, 11 PGG, 10 PCG). Dosing ranged from 0.21 to 1.6 mEq/kg/day for PGT, from 0.25 to 1.48 mEq/kg/day for PGG and from 0.04 to 1.34 mEq/kg/day for PCG. After supplementation, 36/37 cats had an increase in potassium, 34/37 increased to within the reference interval and 24/37 had an increase in potassium to >4 mEq/l. There was a statistically significant difference in serum potassium post-supplementation for all three treatments: PGT (P = 0.0001), PGG (P = 0.001) and PCG (P = 0.002). There was a positive correlation between PGT dose and change in potassium concentration (P = 0.04), but there was no significant correlation for PGG or PCG. In cats that had data available, serum bicarbonate increased >2 mEq/l in 1/6 PGT, 1/6 PGG and 3/4 PCG cats. CONCLUSIONS AND RELEVANCE: All three potassium supplements were effective in treating hypokalemia secondary to CKD in the majority of cats despite variable dosing. Data were limited to assess the alkalinizing effect and prospective studies are needed.

Assessing Acid-Base Status in Circulatory Failure: Relationship Between Arterial and Peripheral Venous Blood Gas Measurements in Hypovolemic Shock.

BACKGROUND AND OBJECTIVES: In severe circulatory failure agreement between arterial and mixed venous or central venous values is poor; venous values are more reflective of tissue acid-base imbalance. No prior study has examined the relationship between peripheral venous blood gas (VBG) values and arterial blood gas (ABG) values in hemodynamic compromise. The objective of this study was to examine the correlation between hemodynamic parameters, specifically systolic blood pressure (SBP) and the arterial-peripheral venous (A-PV) difference for all commonly used acid-base parameters (pH, Pco 2, and bicarbonate). DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: Data were obtained prospectively from adult patients with trauma. When an ABG was obtained for clinical purposes, a VBG was drawn as soon as possible. Patients were excluded if the ABG and VBG were drawn >10 minutes apart. RESULTS: The correlations between A-PV pH, A-PV Pco 2, and A-PV bicarbonate and SBP were not statistically significant (P = .55, .17, and .09, respectively). Although patients with hypotension had a lower mean arterial and peripheral venous pH and bicarbonate compared to hemodynamically stable patients, mean A-PV differences for pH and Pco 2 were not statistically different (P = .24 and .16, respectively) between hypotensive and normotensive groups. CONCLUSIONS: In hypovolemic shock, the peripheral VBG does not demonstrate a higher CO2 concentration and lower pH compared to arterial blood. Therefore, the peripheral VBG is not a surrogate for the tissue acid-base status in hypovolemic shock, likely due to peripheral vasoconstriction and central shunting of blood to essential organs. This contrasts with the selective venous respiratory acidosis previously demonstrated in central venous and mixed venous measurements in circulatory failure, which is more reflective of acid-base imbalance at the tissue level than arterial blood. Further work needs to be done to better define the relationship between ABG and both central and peripheral VBG values in various types of shock.

Adequacy of Preoperative Resuscitation in Laparoscopic Pyloromyotomy and Anesthetic Emergence.

BACKGROUND: Pyloromyotomy is one of the most common surgical procedures performed on otherwise healthy infants. Pyloric stenosis results in a hypochloremic, hypokalemic metabolic alkalosis that is considered a medical emergency. This alkalotic state is believed to be associated with an increased incidence of apneic episodes. Because apnea tends to occur during anesthetic emergence, we sought to examine the association between the preoperative serum bicarbonate level and anesthetic emergence time after laparoscopic pyloromyotomy. METHODS: Data were collected from patients who underwent laparoscopic pyloromyotomies from April 2014 to October 2018. To estimate the correlation between preoperative bicarbonate level and emergence time while accounting for the positive skew of emergence time and potential confounding variables, a weighted quantile mixed regression was used. Due to a nonlinear association with emergence time, preoperative serum bicarbonate was split into 2 continuous intervals (<24 and ≥24 mEq/L) and the slope versus outcome was fit for each interval. RESULTS: A total of 529 patients who underwent laparoscopic pyloromyotomy were analyzed in this study. After controlling for confounders, the preoperative serum bicarbonate interval of ≥24 mEq/L was linearly associated with median emergence time (median increase of 0.81 minutes per 1 mEq/L increase of bicarbonate; 95% confidence interval [CI], 0.42-1.20; P < .001). Only 3 patients (0.6%) had apneic episodes after pyloromyotomy despite all having preoperative serum bicarbonate levels <29 mEq/L. CONCLUSIONS: Preoperative serum bicarbonate was positively associated with median anesthetic emergence time in a linear manner for values ≥24 mEq/L, although this correlation may not appear to be clinically substantial per 1 mEq/L unit. However, when preoperative serum bicarbonate levels were dichotomized at a commonly used presurgical threshold, the difference in median emergence time between ≥30 and <30 mEq/L was an estimated 5.4 minutes (95% CI, 3.1-7.8 minutes; P < .001).