Utility of Stewart's Approach to Diagnose Missed Complex Acid-Base Disorders as Compared to Bicarbonate-anion Gap-based Methodology in Critically Ill Patients: An Observational Study.

BACKGROUND: Traditional arterial blood gas (ABG) analysis may miss out on some metabolic acid-base disorders. We prospectively compared Stewart's approach in critically ill patients to traditional bicarbonate-anion gap-based methods (with and without correction for albumin) to diagnose acid-base disorders. PATIENTS AND METHODS: Five hundred ABG samples from medical or surgical patients in the ICU were analyzed with traditional bicarbonate-anion gap-based methodology with and without correction for albumin and Stewart's biochemical approach. The primary outcome identification of additional metabolic disorders diagnosed with Stewart's approach in comparison to bicarbonate system-based approaches. We also looked at the correlation between the strong ion gap (SIG) and the albumin-corrected anion gap (acAnion Gap). RESULTS: Stewart's approach detected missed metabolic disorders in 58 (11.6%) blood gas results reported as "within normal limits" with the bicarbonate-uncorrected anion gap approach. In 50 (10%) of these ABGs, the acAnion Gap approach was able to diagnose the missed metabolic disorders. Thus, the albumin-corrected anion gap method had a similar diagnostic performance to Stewart's approach, as it missed additional disorders in only eight (1.6%) blood gases. CONCLUSION: In this study, we found that the acAnion Gap approach was similar in diagnostic performance to Stewart's approach. We feel that the corrected anion gap approach can be safely used if a ready calculator for Stewart's approach is not available. HOW TO CITE THIS ARTICLE: Paliwal R, Pakavakis A, Divatia JV, Kulkarni AP. Utility of Stewart's Approach to Diagnose Missed Complex Acid-Base Disorders as Compared to Bicarbonate-anion Gap-based Methodology in Critically Ill Patients: An Observational Study. Indian J Crit Care Med 2022;26(1):23-32.

Ultrasound-guided rectus sheath catheters: A feasible and effective, opioid-sparing, post-operative pain management technique: A case series.

Epidural analgesia, though the gold standard of post-operative pain management for laparotomies, is associated with limitations and is contraindicated in many patients. Opioid-based pain management, which is an alternative to epidural, has been implicated in post-operative nausea, vomiting, and ileus. We report successful management of post operative pain with ultrasound guided rectus sheath (RS) catheters. RS block is a promising alternative in scenarios were epidural is contraindicated, has failed or in case of unexpected change in the surgical plan.