ABG analysis Flashcards
A 20 year old male is brought to the emergency department with diffuse abdominal pain, nausea and vomiting. He provides a history of a gradual increase in polyuria and polydipsia for the past 3 weeks, alongside drowsiness for the past 2 days.
He states he has developed a decreased appetite and says he feels he has lost weight as his clothes fit looser now.
On examination, BP: 106/65mmHg, HR: 130 bpm, RR: 32 bpm and temperature is 37°C. He has Kussmaul breathing, a fruity smell on his breath and generalised abdominal tenderness.
Bloods were done and his ABG shows:
- pH: 7.25 (7.35-7.45)
- PaO2: 12 kPa (11-13kPa)
- PaCO2: 5.3mmHg (4.7-6.0mmHg)
- HCO3-: 17mEq/L (22-26 mEq/L)
- Base excess: -4 (-2 to +2)
- Anion gap: 20mmol (10-18mmol)
- Interpret this set of ABG results.
- What is the most likely explanation for these results
- What causes a raised anion gap?
A 65 year old woman is 7 days post-op, and has been bedbound for just as long, for a right total hip replacement when she describes sudden onset severe pleuritic chest pain and shortness of breath. She states she can feel her heart thumping in her chest. She starts coughing, seeing blood in the phlegm she produces.
The ward nurses hurry to retake her observations and contact the doctor on shift. Quick observations show pulse ox: 85% HR:122 bpm, RR:33 bpm, BP: 110/80 mmHg. An urgent ECG is being done.
ABG is done, and results are shown below:
- pH: 7.48 (7.35-7.45)
- PaO2: 9 kPa (11-13kPa)
- PaCO2: 3.5 mmHg (4.7-6.0mmHg)
- HCO3-: 24mEq/L (22-26 mEq/L)
- Base excess: -2 (-2 to +2)
- Anion gap: 12mmol (10-18mmol)
- Interpret this set of ABG results.
- What is the most likely explanation for these results
- What are the risk factors for this condition?
- A 37 year old male is brought into A&E by a friend, who was visiting to give food, as he was recovering from an RTA (road traffic accident). On presentation, he has a reduced consciousness, his muscles are slack and he has pin-point pupils. He is pale and clammy and is very itchy.
- He starts to choke, creating a snore-like gurgle. His breathing becomes shallow, erratic and slows down significantly.
- Observations show: GCS 7, RR: 6 bpm, HR: 45 bpm, pulse ox: 75%, BP: 83/56 mmHg
He is immediately intubated after an A to E assessment. An ABG is done and the results show:
- pH: 7.23 (7.35-7.45)
- PaO2: 9 kPa (11-13kPa)
- PaCO2: 8.9mmHg (4.7-6.0mmHg)
- HCO3-: 25mEq/L (22-26 mEq/L)
- Base excess: -2 (-2 to +2)
- Anion gap: 12mmol (10-18mmol)
- interpret this set of ABG results
- What could cause these results and the symptoms?
- A 58 year old woman presented to hospital 2 days ago with increasing dysponea, productive cough, chest tightness and an audible wheeze. She has a history of COPD, so was admitted as her observations were: RR: 25 bpm, HR: 119 bpm BP: 102/66 mmHg, pulse ox: 78% and there seemed to be peripheral oedema.
- She was immediately put on high intensity non invasive ventilation, through a non rebreathe mask. She has been having regular ABGs.
Her ABG results today are shown below:
- pH: 7.53 (7.35-7.45)
- PaO2: 13.1 kPa (11-13kPa)
- PaCO2: 3.5 mmHg (4.7-6.0mmHg)
- HCO3-: 30mEq/L (22-26 mEq/L)
- Base excess: -2 (-2 to +2)
- Anion gap: 14 mmol (10-18mmol)
- Interpret these ABG results
- What is the cause of these abnormal results?
A concerned mother brings her 3 week old daughter to A&E as was advised by 111. Initially her daughter was constipated, but over the last day, has started projectile vomiting after her feeds.
On examination, the baby is clinically dehydrated, and there is a palpable, olive shaped mass in the upper abdomen. They are admitted, and an ultrasound is done alongside bloods and an ABG
The ABG results are shown below:
- pH: 7.56 (7.35-7.45)
- PaO2: 11 kPa (11-13kPa)
- PaCO2: 5.1mmHg (4.7-6.0mmHg)
- HCO3-: 32mEq/L (22-26 mEq/L)
- Base excess: +5 (-2 to +2)
- Anion gap: 12mmol (10-18mmol)
- Interpret the ABG results
- What symptom is causing the ABG pattern?
- What electrolyte abnormality would you expect in this condition?
