Rapid Response Systems and MET Calls — Clinical Case

DCE Long Case

Patient brief (provided to trainee)

Patient: Mr David Chen, 68 years old, retired engineer. ^[1]

Presenting complaint: The nursing staff activated a MET call at 22:00 on day 3 of admission for a left lower limb cellulitis, because his NEWS2 had risen from 2 to 8 over four hours and he had become confused and breathless. The MET team attended, gave high-flow oxygen, a 500 mL fluid challenge, and broad-spectrum antibiotics, and contacted the medical registrar (you) for the ongoing review and post-MET plan. ^[1]

Past history: Type 2 diabetes (metformin 1 g twice daily and empagliflozin 10 mg daily, last HbA1c 64 mmol/mol), ischaemic heart disease (prior NSTEMI two years ago, treated with PCI and a drug-eluting stent; currently on aspirin 100 mg daily, atorvastatin 80 mg nocte, bisoprolol 5 mg daily), hypertension, and stage 3 chronic kidney disease (baseline creatinine 130 micromol/L, attributed to hypertensive and ischaemic nephropathy). He lives independently with his wife. He has no formal advance care directive. ^[1]

Observation trend (from the chart):

• 18:00: respiratory rate 20, SpO2 96 per cent on air, HR 88, BP 118 over 72, temp 37.6, GCS 15. NEWS2 of 2.
• 19:00: respiratory rate 24, SpO2 94 per cent on air, HR 98, BP 108 over 68, temp 37.9, GCS 15. NEWS2 of 5.
• 21:00: respiratory rate 28, SpO2 91 per cent on air, HR 114, BP 96 over 60, temp 38.5, GCS 15. NEWS2 of 7.
• 22:00 (MET call): respiratory rate 30, SpO2 88 per cent on air, HR 128, BP 84 over 52, temp 38.9, GCS 14 with new confusion. NEWS2 of 8. ^[1]

Examination findings (at your post-MET review):

• Airway: patent, speaking in short sentences.
• Breathing: respiratory rate 28, SpO2 90 per cent on 15 L via reservoir mask, accessory muscle use, coarse crackles at the left base.
• Circulation: heart rate 124 in new atrial fibrillation, blood pressure 88 over 54 after the 500 mL fluid challenge, capillary refill 4 seconds, mottled peripheries, JVP not visibly elevated.
• Disability: GCS 14 (new mild confusion, E4 V4 M6), pupils equal and reactive, bedside glucose 9.2.
• Exposure: temperature 38.9, the left lower limb cellulitis with spreading erythema from the mid-shin to the mid-thigh, warmth, and tenderness, but no crepitus, blistering, or skin necrosis. ^[1]

Investigations (available results):

• Lactate 4.0 mmol/L (raised).
• Creatinine 195 micromol/L (up from baseline 130).
• Potassium 5.6 mmol/L.
• White cell count 22.4, CRP 280.
• Venous gas: pH 7.28, base excess negative 6.
• ECG: atrial fibrillation at a ventricular rate of 124, no acute ischaemic changes, peaked T waves consistent with the hyperkalaemia.
• Chest X-ray: small left pleural effusion, no focal consolidation. ^[1]

Drug chart on admission (current): aspirin 100 mg daily, atorvastatin 80 mg nocte, bisoprolol 5 mg daily, metformin 1 g twice daily, empagliflozin 10 mg daily, IV flucloxacillin 2 g four-hourly (day 3), subcutaneous enoxaparin 40 mg daily (VTE prophylaxis). ^[1]

Candidate's structured presentation (model)

Opening statement (SASPOP): ^[1]

"Mr David Chen is a 68-year-old retired engineer who was admitted three days ago with a left lower limb cellulitis and has acutely deteriorated overnight with a rising NEWS2 from 2 to 8 over four hours, precipitating a MET call. He has a background of type 2 diabetes, ischaemic heart disease with a prior NSTEMI, and stage 3 chronic kidney disease. He lives independently with his wife. ^[1]

His main problems are:

1. Septic shock from progressive soft-tissue infection — refractory hypotension at 88 over 54 despite a fluid challenge, lactate 4.0, mottled peripheries, oliguric at 20 mL per hour.
2. Acute kidney injury with hyperkalaemia — creatinine risen from 130 to 195, potassium 5.6 with peaked T waves on the ECG.
3. New atrial fibrillation, almost certainly secondary to the sepsis and the electrolyte disturbance.
4. An afferent-limb failure — the NEWS2 crossed the intermediate threshold at 19:00 and the emergency threshold at 21:00, but the MET call was not made until 22:00. ^[1]

My immediate priorities are the continued ABCDE resuscitation with cautious fluid in 250 mL aliquots given his ischaemic heart disease, early noradrenaline if he is not fluid-responsive, treatment of the hyperkalaemia with calcium gluconate and insulin-dextrose, urgent surgical review of the limb for necrotising infection, escalation to ICU for vasopressor and possibly renal replacement therapy, and an early conversation with the family about the ceiling of care." ^[1]

Management plan: ^[1]

1. Continue the resuscitation. High-flow oxygen to target SpO2 92 to 96 per cent. Two large-bore cannulae. Cautious fluid: 250 mL balanced crystalloid over 15 minutes, reassess between each aliquot for responsiveness and overload. Prepare the central line for noradrenaline if the blood pressure does not respond.
2. Treat the hyperkalaemia. Calcium gluconate 10 mL of 10 per cent intravenously over 5 to 10 minutes, insulin-dextrose (10 units of Actrapid in 50 mL of 50 per cent dextrose), salbutamol nebuliser. Monitor the ECG. Recheck the potassium in 30 minutes.
3. Identify and control the source. Urgent surgical review of the limb for necrotising infection (the erythema has spread to the mid-thigh, which is concerning, though there is no crepitus or necrosis yet). Continue broad-spectrum antibiotics; add Gram-negative cover (piperacillin-tazobactam or the local equivalent) given the progression on flucloxacillin alone.
4. Withhold the harmful drugs. Metformin (AKI and lactic acidosis risk), empagliflozin (AKI and euglycaemic ketoacidosis risk), and review the bisoprolol given the hypotension. Switch the enoxaparin to unfractionated heparin given the renal failure. Manage the glucose with a sliding-scale insulin infusion.
5. Escalate to ICU. He has refractory septic shock with multi-organ failure; he needs vasopressor support and possibly renal replacement therapy.
6. The ceiling-of-care conversation. Weigh the reversibility of the sepsis (potentially reversible) against his comorbidities (ischaemic heart disease, CKD) and his baseline function (independent). Offer a time-limited trial of ICU. Ask the family early about his wishes.
7. The post-MET plan. Continuous monitoring, hourly observations, hourly urine output, serial lactate and potassium, named responsible consultant, review timeline, and documented communication with the team and family. ^[1]

Communication and shared decision-making: Explain to the family that Mr Chen has become much more unwell with the infection spreading and that the body is struggling to compensate. Explain that the immediate priorities are to support the blood pressure, treat the infection, and correct the potassium. Explain that the next 48 hours will tell whether the treatment is working. Ask, gently, what he would want. Surface the ceiling-of-care conversation early and document it. ^[1]

Examiner discussion questions

Q1: "The NEWS2 crossed 5 at 19:00 and 7 at 21:00, but the MET call was at 22:00. Analyse the afferent-limb failure and describe the system fix." ^[1]

"The afferent limb failed at both thresholds. A NEWS2 of 5 to 6 mandates an urgent ward-registrar review within 30 minutes and hourly monitoring ^[3]; the patient crossed that at 19:00 and was not reviewed. A NEWS2 of 7 or more mandates an emergency critical care assessment within minutes; the patient crossed that at 21:00 and the call was not made until 22:00. The respiratory rate was the rising parameter throughout — from 20 at 18:00 to 30 at 22:00 — which is the classic leading indicator that is most frequently omitted and most frequently neglected when documented. This is the failure mode the MERIT study exposed: the team was called to only 30 per cent of patients who met criteria ^[1]. The system fixes are: ward education in recognising and acting at the intermediate threshold (not waiting for the emergency threshold); the visible observation chart that displays the trend; the bedside escalation signage that flags a rising score; the cultural message that it is always acceptable to call; and the feedback to the ward team after the event, which closes the quality-improvement loop. The four-limb model from the 2005 consensus conference frames this: the efferent limb (the team) functioned when called; the afferent limb (the detection) failed; the governance and quality-improvement limbs are the mechanism for the fix ^[2]."

Q2: "How would you adjust the standard sepsis fluid resuscitation for his ischaemic heart disease?" ^[1]

"The Surviving Sepsis Campaign 2021 recommendation of 30 mL per kilogram crystalloid in the first three hours gives the total amount ^[4]; his ischaemic heart disease and likely diastolic dysfunction dictate that I deliver it in smaller aliquots with reassessment between each. My approach is 250 mL of balanced crystalloid over 15 minutes, then reassess for fluid responsiveness — a rise in blood pressure, a fall in heart rate, an improvement in capillary refill, a rise in urine output — and for signs of overload — a rise in JVP, new basal crackles, a fall in SpO2, increasing work of breathing. If he is fluid-responsive and not overloading, I repeat the bolus, working towards the 30 mL per kilogram total over three hours. If he is not fluid-responsive — which, given his refractory hypotension, is likely — I start noradrenaline early via the central line to restore the MAP to above 65, and I use a focused bedside echocardiogram or a passive leg raise to guide the fluid dynamically. The principle: the comorbidity does not override the guideline, but it modifies the aliquot size, the reassessment frequency, and the threshold for vasopressor support."

Q3: "What is the role of the MET call in his ceiling-of-care conversation?" ^[1]

"The MET call is the trigger for the conversation. The patient who has deteriorated to the point of a MET call is the patient for whom the question of escalation is live. The MET team's assessment gives the information; the registrar's job is to use it to set the goals of care honestly with the family. He is a previously independent 68-year-old with potentially reversible septic shock, which favours escalation; he has ischaemic heart disease and CKD, which complicate the prognosis. The observation from MERIT that the MET system increased the rate of not-for-resuscitation orders is part of the system's function — it surfaces the conversation at the moment it matters ^[1]. I offer a time-limited trial of ICU as the considered middle path: maximal support for a defined 48 to 72 hour period, with a clear review point, and a commitment to revisit the plan with the family. If the treatment is working and he is recovering, we continue; if it is not, we refocus on comfort. I document the conversation, the values expressed, the plan, and the review point."

Q4: "What is the single most important lesson from this case about the Rapid Response System?" ^[1]

"The single most important lesson is that the afferent limb is the weakest link, and the system only works if the call is made. The four-limb model from the 2005 consensus conference is not an abstraction — it maps directly onto this case ^[2]. The efferent limb (the MET team) functioned: it arrived, assessed, resuscitated, and escalated. The governance limb (the calling criteria, the NEWS2 chart) was in place. But the afferent limb failed: the deterioration was documented, the score crossed the thresholds, and the call was delayed by an hour at the emergency threshold and by three hours at the intermediate threshold. The fix is the education and the culture of the ward — the training of the nurses and junior doctors to measure the respiratory rate, to calculate the score, to recognise the trend, and to escalate without hesitation. The second lesson is the integration: the resuscitation, the source control, the hyperkalaemia protocol, the drug review, and the ceiling-of-care decision are not separate tasks but a single coordinated response. And the third is the post-MET plan — the goals of care, the ceiling of treatment, the monitoring, and the communication are the registrar's ongoing responsibility, and they are part long-case examiner will probe."