Critical Cases - Severe Metabolic Acidosis!

Tue, 11/09/2021 - 5:11am
Author: 
Angela Ugorets, MD
Editor: 
Richard Byrne, MD

HPI:

36 year old male with a history of IV drug use presents with 5 days of shortness of breath

PE:

VS: BP 43/24 HR 115 RR 40 SpO2 98% Rectal Temp: 94.5F (34.7C)

  • Patient appears distressed, severe tachypnea and increased work of breathing
  • Heart: tachycardia, no murmur
  • Pulm: tachypneic, lungs clear
  • Aabdomen: diffuse tenderness
  • Extrem: small left arm abscess no crepitus or tenderness of his arm

Initial ED Treatment

  • Obtain 2 large bore IVs with ultrasound
  • LR bolus under pressure bag
  • Broad spectrum antibiotics (Vancomycin and Cefepime)
  • Bedside echo shows hyperdynamic heart
  • Rpt BP after IVF 104/55

Labs

  • VBG: pH 7.09, pCO2 27
  • CBC: WBC 92K, Plt 10K
  • BMP: Glu 47, BUN 148, Cr 4.02, K 5.7, HCO3: 7, Anion Gap: 31
  • Lactic Acid: 10

Differential Diagnosis

  • Septic shock, possibly due to bacteremia/endocarditis 
  • Massive pulmonary embolism: hypotension and tachypnea with clear lungs
  • Renal failure causing metabolic acidosis
  • TTP - given low platelets, renal failure
  • Heme Malignancy - given severely elevated WBC
  • DIC

 

Further treatment and outcome

  • Nephrology consult: recco bicarb gtt and dialysis catheter placement
  • Heme Onc consulted - no schistocytes, no blasts on smear. Elevated WBC likely leukemoid reaction. Thrombocytopenia likely d/t consumptive process such as bacteremia.
  • Pt admitted to ICU and HD started 
  • CT chest showed septic emboli in lungs
  • Pt improved rapidly overly 24 hrs
  • 2D TTE showed tricuspid vegetations concerning for endocarditis.
  • Blood cultures grew STREPTOCOCCUS MITIS / ORALIS and NEISSERIA FLAVESCENS SUBFLAVA GROUP

Pearls:

  • This patient had a severe metabolic acidosis 
  • Is the patient compensating?  Use Winter's Formula --> PCO2 = 1.5 x HCO3 + 8 +/- 2 In this case: 1.5 x 7 + 8 +/- 2 = 16.5-20.5 which is LESS than his PCO2 of 27 --> primary respiratory acidosis.
  • Pts cannot fully compensate for severe metabolic acidosis
  • Try not avoid intubation: even 1 minute of apnea during intubation will drop the pH and may cause cardiac arrest
  • Attempt to at least partially correct acidosis before intubation, minimize apnea time, and set ventilator to match pts pre-intubation minute volume (TV X RR)
  • Remember the peri-intubation killers: Acidosis, hypotension, hypoxia