Confirm, then start the clock
Repeat the measurement and check the cuff. Then treat the low pressure as an exposure that is accruing, not a reading that is either normal or abnormal.
Every 10 minutes counts. In the trial substudy, the odds of myocardial infarction or death rose with each 10-minute increase in the duration of hypotension, an odds ratio of 1.08 (98.3% CI 1.03 to 1.12) intraoperatively and 1.03 (98.3% CI 1.01 to 1.05) for the rest of the day of surgery sessler-2018. The consensus statement puts a systolic pressure below 90 mmHg, or more than 30% below baseline, at the level likely to put most patients at risk of end-organ injury mcevoy-2019.
An absolute number is enough to act on: absolute mean-pressure thresholds perform about as well as percentage reductions from a patient’s own baseline salmasi-2017.
Work the differential while you treat
-
General recommendation. Hypovolemia and ongoing bleeding. Look at the drains, the dressing, the abdomen and the hemoglobin. This is the first thing to exclude in a patient who was fine in the operating room. Widely taught and not verified against a primary source by this project; it carries no ledger entry. Follow your institution's protocol.
-
General recommendation. Vasodilatation from residual anesthetic, or a neuraxial sympathectomy that is still ascending. Warm, well-perfused peripheries with a low pressure and a low or normal heart rate. Widely taught and not verified against a primary source by this project; it carries no ledger entry. Follow your institution's protocol.
-
General recommendation. Anaphylaxis. Widely taught and not verified against a primary source by this project; it carries no ledger entry. Follow your institution's protocol. Hypotension is the presenting feature in 46% of perioperative anaphylaxis, and skin signs may be absent in the severe grades until perfusion is restored garvey-2019. If this is on your list, go to the anaphylaxis dosing on Day 20 now rather than after a fluid bolus.
-
General recommendation. Cardiac causes: ischemia, a new arrhythmia, tamponade, pulmonary embolism, tension pneumothorax. Look at the rhythm, the neck veins and the breath sounds, and get an electrocardiogram. Widely taught and not verified against a primary source by this project; it carries no ledger entry. Follow your institution's protocol.
-
General recommendation. Sepsis, particularly after abdominal or urological surgery in a patient who was febrile beforehand. Widely taught and not verified against a primary source by this project; it carries no ledger entry. Follow your institution's protocol.
First moves
General recommendation. A fluid bolus with phenylephrine about 50 to 100 micrograms or ephedrine about 5 to 10 mg, chosen by the heart rate, and escalation to a norepinephrine infusion if the pressure does not hold. None of these agents has outcome evidence in this setting. Widely taught and not verified against a primary source by this project; it carries no ledger entry. Follow your institution's protocol.
Local practice differs. the pressure at which a PACU protocol triggers treatment, and the first-line agent, differ between institutions; follow local protocol.
Before discharge
Count the dose the patient has already taken, and ask who is watching next. On the ward, vital signs are taken every 4 to 6 hours, and prolonged hypotension on postoperative days 1 to 4 can go unseen; the odds of a poor outcome in that period are described as almost three times as high mcevoy-2019.
What this card cannot tell you is whether treating the exposure changes the outcome. Every source here is observational, including the cohort analysis inside a randomized trial sessler-2018 liem-2020.
Sources
[[sessler-2018]] cohort 2018 n: 9765 open
Sessler DI, Meyhoff CS, Zimmerman NM, et al. Period-dependent associations between hypotension during and for four days after noncardiac surgery and a composite of myocardial infarction and death: a substudy of the POISE-2 trial. Anesthesiology. 2018 Feb;128(2):317-327.
Substudy of POISE-2 (10,010-patient factorial RCT); clinically important hypotension defined as SBP <90 mmHg requiring treatment; among 9,765 patients 42% experienced hypotension, 590 (6.0%) had infarction and 116 (1.2%) died within 30 days; intraoperative estimated average relative effect across MI and mortality 1.08 (98.3% CI 1.03-1.12). THE EXPOSURE UNIT FOR THAT 1.08 IS CUT OFF IN THE ABSTRACT - confirm in full text before writing it.
[[liem-2020]] cohort 2020 n: 1710 paywalled
Liem VGB, Hoeks SE, Mol KHJM, et al. Postoperative hypotension after noncardiac surgery and the association with myocardial injury. Anesthesiology. 2020;133:510-522.
Single-centre observational cohort of 1710 patients aged 60 or older having intermediate- to high-risk noncardiac surgery, with frequent haemodynamic sampling on a postoperative high-dependency ward for the first 24 h; multiple absolute MAP thresholds from 50 to 75 mmHg characterised by cumulative minutes, duration and area under threshold. This is the closest published analogue to a PACU exposure model.
[[mcevoy-2019]] consensus statement 2019 n: NA open
McEvoy MD, Gupta R, Koepke EJ, et al. Perioperative Quality Initiative consensus statement on postoperative blood pressure, risk and outcomes for elective surgery. Br J Anaesth. 2019;122(5). (page range UNVERIFIED)
POQI-3 postoperative-BP statement: a systolic pressure below 90 mmHg or more than 30% below baseline is likely to put most patients at risk of end-organ injury; risk rises with each 10-min epoch of hypotension intraoperatively and on POD0; the odds ratio for poor outcome with hypotension is described as almost three times as high on POD1-4, a period when prolonged hypotension can go unseen because ward vital signs are taken only every 4-6 h. This is the source for the dose-and-duration framing of the day.
[[salmasi-2017]] cohort 2017 n: UNVERIFIED paywalled
Salmasi V, Maheshwari K, Yang D, Mascha EJ, Singh A, Sessler DI, Kurz A. Relationship between intraoperative hypotension, defined by either reduction from baseline or absolute thresholds, and acute kidney and myocardial injury after noncardiac surgery: a retrospective cohort analysis. Anesthesiology. 2017;126:47-65.
The absolute-threshold versus relative-reduction comparison. Carries the finding that absolute MAP thresholds perform about as well as percentage reductions from baseline, which is what lets a PACU protocol use a fixed number.
[[garvey-2019]] consensus statement 2019 n: NA (26 experts, modified Delphi) open
Garvey LH, Dewachter P, Hepner DL, et al. Management of suspected immediate perioperative allergic reactions: an international overview and consensus recommendations. Br J Anaesth. 2019 Jul;123(1):e50-e64.
Grading (modified Ring and Messmer, Table 1): I skin/mucosal only; II moderate multi-organ; III life-threatening hypotension/tachy- or bradycardia/severe bronchospasm; IV cardiac or respiratory arrest; skin signs may be absent in III/IV until perfusion restored. Table 4 adult doses: Grade II i.v. epinephrine 20 microg, escalate to 50 microg at 2 min, repeat q2 min, 300 microg i.m. if no i.v. access, crystalloid 500 ml; Grade III 50 microg (100 microg if unresponsive to other vasopressors), escalate to 200 microg at 2 min, crystalloid 1 L repeated up to 30 ml/kg; Grade IV 1 mg per ALS, ECM if SBP <50 mmHg or EtCO2 <3 kPa; refractory >10 min: double dose, infusion 0.05-0.1 microg/kg/min after >3 boluses, vasopressin 1-2 IU, glucagon 1-2 mg if beta-blocked, norepinephrine 0.05-0.5 microg/kg/min, ECLS. Tryptase at 1 h, 2-4 h, baseline >=24 h. 'Sugammadex has no immediate role in resuscitation of suspected anaphylaxis.'