Intraoperative Hypertension: Differential and Treatment
CA-1 · intraoperative teaching CA-1 Bootcamp day 12. Authored from cited abstracts; every claim carries a PMID.
THE QUESTIONWhere the evidence disagrees
This topic was selected because an evidence synthesis beats a textbook on it: the trials disagree, or the guidance has moved recently.
THE EVIDENCE
What each source contributes, and how strong it is
Study design first — a cohort and a randomised trial do not carry the same weight.
Design
Year
Journal
What it found
Other
1977
Anesthesia and Analgesia
Start with the patient rather than the pressure
Other
1978
Archives of Surgery
Look at the capnograph and the saturation before you look at the drug drawer
Other
2017
Spinal Cord Series and Cases
A full bladder deserves a place on the list rather than a joke
Other
2017
Journal of Cardiothoracic and Vasc
Phaeochromocytoma is the rare cause worth naming out loud
Other
1992
Canadian Journal of Anaesthesia
Labetalol given as 5 mg intravenous increments lowered systolic and diastolic
Other
2022
Pregnancy Hypertension
Hydralazine 10 mg intravenously matched incremental labetalol for lowering mea
9 resolved citations behind this deck; every point above traces to one of them.
IN PRACTICE
What the cohorts and reviews add
6 findings, each on the slide that follows.
Anesthesia and Analgesia 1977
Start with the patient rather than the pressure
Start with the patient rather than the pressure, because a noxious stimulus alone will do this: in unpremedicated control patients, laryngoscopy and…
Archives of Surgery 1978
Look at the capnograph and the saturation before you look at the drug drawer
Look at the capnograph and the saturation before you look at the drug drawer, because both derangements raise blood pressure through the sympathetic…
Spinal Cord Series and Cases 2017
A full bladder deserves a place on the list rather than a joke
A full bladder deserves a place on the list rather than a joke, because in a patient with a high spinal cord injury bladder distension is the classic…
Journal of Cardiothoracic and Vascular Anesthesia 2017
Phaeochromocytoma is the rare cause worth naming out loud
Phaeochromocytoma is the rare cause worth naming out loud, because in an unprepared patient the catecholamine surge provoked by induction or by the…
IN PRACTICE
Start with the patient rather than the pressure
Other · Anesthesia and Analgesia
Start with the patient rather than the pressure, because a noxious stimulus alone will do this: in unpremedicated control patients, laryngoscopy and intubation raised mean arterial pressure by an average of 39 mmHg and heart rate by about 20 beats per minute.
Stoelting, Anesthesia and Analgesia 1977 · PMID 562086
IN PRACTICE
Look at the capnograph and the saturation before you look at the drug drawer
Other · Archives of Surgery
Look at the capnograph and the saturation before you look at the drug drawer, because both derangements raise blood pressure through the sympathetic nervous system - allowing arterial carbon dioxide to reach 56 to 65 mmHg under anaesthesia raised systolic pressure, heart rate and cardiac output with a two- to threefold rise in plasma catecholamines, and hypoxia is a recognised driver of sympathoexcitation in its own right.
Rasmussen et al., Archives of Surgery 1978 · PMID 708241
IN PRACTICE
A full bladder deserves a place on the list rather than a joke
Other · Spinal Cord Series and Cases
A full bladder deserves a place on the list rather than a joke, because in a patient with a high spinal cord injury bladder distension is the classic trigger for autonomic dysreflexia and suprapubic pressure alone has been documented driving systolic pressure to 230 mmHg in a woman whose resting pressure was 100/64.
Lee et al., Spinal Cord Series and Cases 2017 · PMID 29423304
IN PRACTICE
Phaeochromocytoma is the rare cause worth naming out loud
Other · Journal of Cardiothoracic and Vasc
Phaeochromocytoma is the rare cause worth naming out loud, because in an unprepared patient the catecholamine surge provoked by induction or by the surgeon's hand on the tumour produces cardiovascular complications that are life-threatening rather than merely inconvenient.
Naranjo et al., Journal of Cardiothoracic and Vascular Anesthesia 2017 · PMID 28392094
IN PRACTICE
Labetalol given as 5 mg intravenous increments lowered systolic and diastolic
Other · Canadian Journal of Anaesthesia
Labetalol given as 5 mg intravenous increments lowered systolic and diastolic pressure within ten minutes and held the effect for at least two hours with only a moderate fall in heart rate, whereas esmolol in the same elderly patients produced bradycardia severe enough that the infusion had to be stopped in two of them - so labetalol is the easier choice when the pressure is high and the heart rate is not.
Singh et al., Canadian Journal of Anaesthesia 1992 · PMID 1353708
IN PRACTICE
Hydralazine 10 mg intravenously matched incremental labetalol for lowering mea
Other · Pregnancy Hypertension
Hydralazine 10 mg intravenously matched incremental labetalol for lowering mean arterial pressure in a randomised trial of severe hypertension in pregnancy, but hypertensive-crisis reviews still place nicardipine, labetalol and esmolol ahead of both hydralazine and nitroglycerine, because the agents you want in an operating room are the short-acting titratable ones you can stop when the stimulus stops.
Muhammad et al., Pregnancy Hypertension 2022 · PMID 35605426
IN THE ROOM
What this changes about the next case
Colour is the strength of the evidence behind each step, not the urgency.
1
1
Start with the patient rather than the pressure, because a noxious stimulus alone will do this: in unpremedicated control patients, laryngoscopy and intubation raised mean arterial pressure by an average of 39 mmHg and heart rate by about 20 beats per minute.
2
2
Look at the capnograph and the saturation before you look at the drug drawer, because both derangements raise blood pressure through the sympathetic nervous system - allowing arterial carbon dioxide to reach 56 to 65 mmHg under anaesthesia raised systolic pressure, heart rate and cardiac output with a two- to threefold rise in plasma catecholamines, and hypoxia is a recognised driver of sympathoexcitation in its own right.
3
3
A full bladder deserves a place on the list rather than a joke, because in a patient with a high spinal cord injury bladder distension is the classic trigger for autonomic dysreflexia and suprapubic pressure alone has been documented driving systolic pressure to 230 mmHg in a woman whose resting pressure was 100/64.
4
4
Phaeochromocytoma is the rare cause worth naming out loud, because in an unprepared patient the catecholamine surge provoked by induction or by the surgeon's hand on the tumour produces cardiovascular complications that are life-threatening rather than merely inconvenient.
5
5
Labetalol given as 5 mg intravenous increments lowered systolic and diastolic pressure within ten minutes and held the effect for at least two hours with only a moderate fall in heart rate, whereas esmolol in the same elderly patients produced bradycardia severe enough that the infusion had to be stopped in two of them - so labetalol is the easier choice when the pressure is high and the heart rate is not.
The oral-boards stem on the next slide puts these into one scenario.
KEY TAKEAWAYS
What to carry into the next case
Start with the patient rather than the pressure
Anesthesia and Analgesia 1977
Look at the capnograph and the saturation before you look at the drug drawer
Archives of Surgery 1978
A full bladder deserves a place on the list rather than a joke
Spinal Cord Series and Cases 2017
Phaeochromocytoma is the rare cause worth naming out loud
Journal of Cardiothoracic and Vascular Anesthesia 2017
Intraoperative hypertension is a symptom, and the two commonest causes - a patient who is too light and a patient who is in pain - are both treated with anaesthesia and analgesia rather than an antihypertensive, so the drug comes after you have deepened, checked the gas exchange and looked at the bladder.
Questions I'll ask you in the room
Before you give anything: what are the three things on this monitor that could be causing this number?
How would you tell light anaesthesia from inadequate analgesia here, and would your treatment differ?
Why might I be reluctant to give hydralazine to this patient in the middle of a case?
The pressure comes down and then, ten minutes later, it is 200 systolic again with a temperature of 38.4 - what has changed in your differential?
Oral boards stem
A 62-year-old man with treated hypertension is having an open hemicolectomy. Forty minutes in, as the surgeon retracts hard on the mesentery, the arterial line reads 195/104 and the heart rate climbs from 62 to 94. The end-tidal sevoflurane is 0.6 MAC, the last opioid was 100 micrograms of fentanyl at induction, and the end-tidal carbon dioxide has crept from 34 to 47 mmHg over the last ten minutes. Your attending asks what you are going to do. Tell me your differential in the order you would work through it, and then tell me what you would give and why.
The bottom lineIntraoperative hypertension is a symptom, and the two commonest causes - a patient who is too light and a patient who is in pain - are both treated with anaesthesia and analgesia rather than an antihypertensive, so the drug comes after you have deepened, checked the gas exchange and looked at the bladder.
Sources
[1] Stoelting, Anesthesia and Analgesia 1977 · PMID 562086 open
[2] Rasmussen et al., Archives of Surgery 1978 · PMID 708241 open
[3] Simpson et al., The Journal of Physiology 2024 · PMID 38533641 open
[4] Lee et al., Spinal Cord Series and Cases 2017 · PMID 29423304 open
[5] Naranjo et al., Journal of Cardiothoracic and Vascular Anesthesia 2017 · PMID 28392094 open
[6] Singh et al., Canadian Journal of Anaesthesia 1992 · PMID 1353708 open
[7] Muhammad et al., Pregnancy Hypertension 2022 · PMID 35605426 open
[8] Varon and Marik, Drugs 2008 · PMID 18257607 open
[9] Rodriguez et al., Cardiology in Review 2010 · PMID 20160537 open