Objectives: To investigate the acid-base status of sick goats using the simplified strong ion difference (sSID) approach, to establish the quantitative contribution of sSID variables to changes in blood pH and HCO 3 − and to determine whether clinical, acid-base, and biochemical variables on admission are associated with the mortality of sick goats. Animals: One hundred forty-three sick goats. Methods: Retrospective study. Calculated sSID variables included SID using 6 electrolytes unmeasured strong ions (USI) and the total nonvolatile buffer ion concentration in plasma (A tot). The relationship between measured blood pH and HCO 3 − , and the sSID variables was examined using forward stepwise linear regression. Cox proportional hazard models were constructed to assess associations between potential predictor variables and mortality of goats during hospitalization. Results: Hypocapnia, hypokalemia, hyperchloremia, hyperlactatemia, and hyperproteinemia were common abnormalities identified in sick goats. Respiratory alkalosis, strong ion acidosis, and A tot acidosis were acid-base disorders frequently encountered in sick goats. In sick goats, the sSID variables explained 97% and 100% of the changes in blood pH and HCO 3 − , respectively. The results indicated that changes in the respiratory rate (<16 respirations per minute), USI, and pH at admission were associated with increased hazard of hospital mortality in sick goats. Conclusions and Clinical Importance: The sSID approach is a useful methodology to quantify acid-base disorders in goats and to determine the mechanisms of their development. Clinicians should consider calculation of USI in sick goats as part of the battery of information required to establish prognosis.

Summary A retrospective study was made of the course and outcome of labour in 226 patients in whom a singleton fetus presented by the breech. Patients with macerated stillbirths or who were delivered before the 28th week of gestation had been excluded. Of the 226 patients, 101 received extradural analgesia, 79 received parenteral analgesia and 46 underwent elective Caesarean section. There was no difference in the incidence of breech extraction or emergency Caesarean section in the first two groups of patients. The length of both first and second stages of labour in multiparae was prolonged in the extradural group, but not markedly so. The Apgar scores of the infants delivered vaginally were not significantly different at one minute in both groups but the five minute Apgar score in the infants of primiparae was significantly higher in the extradural group. The Apgar score at one minute in the group delivered by emergency Caesarean section was significantly lower after extradural block but the difference was not significant at five minutes. This study suggests that the management and outcome of labour when the breech presents is not adversely affected by the provision of extradural analgesia.

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Background: Use of different analyzers to measure electrolytes in the same horse can lead to different interpretation of acid-base balance when using the simplified strong ion difference (sSID) approach. Objective: Investigate the level of agreement between 2 analyzers in determining electrolytes concentrations, sSID variables, and acid-base disorders in sick horses. Animals: One hundred twenty-four hospitalized horses. Methods: Retrospective study using paired samples. Electrolytes were measured using a Beckman Coulter AU480 Chemistry analyzer (PBMA) and a Nova Biomedical Stat Profile (WBGA), respectively. Calculated sSID variables included strong ion difference, SID 4 ; unmeasured strong ions, USI; and total nonvolatile buffer ion concentration in plasma (A tot). Agreement between analyzers was explored using Passing-Bablok regression and Bland-Altman analysis. Kappa (κ) test evaluated the level of agreement between analyzers in detecting acid-base disorders. Results: Methodologic differences were identified in measured Na + and Cl − and calculated values of SID 4 and USI. Mean bias (95% limits of agreement) for Na + , Cl − , SID 4 , and USI were: −1.2 mmol/L (−9.2 to 6.8), 4.4 mmol/L (−4.4 to 13), −5.4 mmol/L (−13 to 2), and −6.2 mmol/L (−14 to 1.7), respectively. The intraclass correlation coefficient for SID 4 and USI was .55 (95%CI: −0.2 to 0.8) and .2 (95%CI: −0.15 to 0.48), respectively. There was a poor agreement between analyzers for detection of SID 4 (κ = 0.20, 95%CI, 0.1 to 0.31) or USI abnormalities (κ = −0.04, 95% CI, −0.11 to 0.02). Abbreviations: A − , total net negative charge of plasma proteins; AG, anion gap; Atot, total plasma concentration of nonvolatile weak acids; HCO3 − , bicarbonate; ICC, intraclass correlation coefficient; L-lac − , L-lactate; P v CO 2 , venous partial carbon dioxide pressure; SID, strong ion difference; SIDm, measured strong ion difference; SIG, strong ion gap; sSID, simplified strong ion difference approach; TP, total protein; TS, total solids; USI, unmeasured strong ions.