Lab case 168

64 year old male presents to ED c/o 1 day history of cough and SOB. The symptoms started suddenly in the early hours of the morning.

No infective symptoms. The patient has a background of mild COPD with no previous admissions. Due to increased work of breathing the patient was put on BiPAP and commenced on salbutamol and ipratropium bromide nebs

Arterial Blood Gas on FiO2 .4

pH7.20                                                                                  Na 139 mmol/L

pCO2 72 mmHg                                                                 K4.7  mmol/L

pO2 92 mmHg                                                                    Cl 107  mmol/L

HCO3 27 mmol/L                                                              Cr 189 umol/L

Lactate 1.9                                                                          Glucose 7.2 mmol/L

Sats 96%


Repeat VBG done after 2 hours on BiPAP in order to monitor response. Clinically the patient had minimally improved

pH 7.14                                                                                 Na 139 mmol/L

pCO2 88mmHg                                                                  K4.5 mmol/L

pO2 42 mmHg                                                                    Cl 106 mmol/L

HCO3 28 mmol/L                                                              Cr 190umol/L

Sats 68%

Lactate 1.9


  1. Describe and interpret the initial ABG
  2. What reasons could account for the patients lack of response to BiPAP