Withholding versus Continuing Angiotensin-converting Enzyme Inhibitors or Angiotensin II Receptor Blockers before Noncardiac Surgery

2018 ESC/ESH Guidelines for the management of arterial hypertension: The Task Force for the management of arterial hypertension of the European Society of Cardiology and the European Society of Hypertension: The Task Force for the management of arterial hypertension of the European Society of Cardiology and the European Society of Hypertension

: Document reviewers: Guy De Backer (ESC Review Co-ordinator) (Belgium), Anthony M. Heagerty (ESH Review Co-ordinator) (UK), Stefan Agewall (Norway), Murielle Bochud (Switzerland), Claudio Borghi (Italy), Pierre Boutouyrie (France), Jana Brguljan (Slovenia), Héctor Bueno (Spain), Enrico G. Caiani (Italy), Bo Carlberg (Sweden), Neil Chapman (UK), Renata Cifkova (Czech Republic), John G. F. Cleland (UK), Jean-Philippe Collet (France), Ioan Mircea Coman (Romania), Peter W. de Leeuw (The Netherlands), Victoria Delgado (The Netherlands), Paul Dendale (Belgium), Hans-Christoph Diener (Germany), Maria Dorobantu (Romania), Robert Fagard (Belgium), Csaba Farsang (Hungary), Marc Ferrini (France), Ian M. Graham (Ireland), Guido Grassi (Italy), Hermann Haller (Germany), F. D. Richard Hobbs (UK), Bojan Jelakovic (Croatia), Catriona Jennings (UK), Hugo A. Katus (Germany), Abraham A. Kroon (The Netherlands), Christophe Leclercq (France), Dragan Lovic (Serbia), Empar Lurbe (Spain), Athanasios J. Manolis (Greece), Theresa A. McDonagh (UK), Franz Messerli (Switzerland), Maria Lorenza Muiesan (Italy), Uwe Nixdorff (Germany), Michael Hecht Olsen (Denmark), Gianfranco Parati (Italy), Joep Perk (Sweden), Massimo Francesco Piepoli (Italy), Jorge Polonia (Portugal), Piotr Ponikowski (Poland), Dimitrios J. Richter (Greece), Stefano F. Rimoldi (Switzerland), Marco Roffi (Switzerland), Naveed Sattar (UK), Petar M. Seferovic (Serbia), Iain A. Simpson (UK), Miguel Sousa-Uva (Portugal), Alice V. Stanton (Ireland), Philippe van de Borne (Belgium), Panos Vardas (Greece), Massimo Volpe (Italy), Sven Wassmann (Germany), Stephan Windecker (Switzerland), Jose Luis Zamorano (Spain).The disclosure forms of all experts involved in the development of these Guidelines are available on the ESC website www.escardio.org/guidelines.

Association between peri-operative angiotensin-converting enzyme inhibitors and angiotensin-2 receptor blockers and acute kidney injury in major elective non-cardiac surgery: a multicentre, prospective cohort study

The peri-operative use of angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers is thought to be associated with an increased risk of postoperative acute kidney injury. To reduce this risk, these agents are commonly withheld during the peri-operative period. This study aimed to investigate if withholding angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers peri-operatively reduces the risk of acute kidney injury following major non-cardiac surgery. Patients undergoing elective major surgery on the gastrointestinal tract and/or the liver were eligible for inclusion in this prospective study. The primary outcome was the development of acute kidney injury within seven days of operation. Adjusted multi-level models were used to account for centre-level effects and propensity score matching was used to reduce the effects of selection bias between treatment groups. A total of 949 patients were included from 160 centres across the UK and Republic of Ireland. From this population, 573 (60.4%) patients had their angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers withheld during the peri-operative period. One hundred and seventy-five (18.4%) patients developed acute kidney injury; there was no difference in the incidence of acute kidney injury between patients who had their angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers continued or withheld (107 (18.7%) vs. 68 (18.1%), respectively; p = 0.914). Following propensity matching, withholding angiotensin-converting enzyme inhibitors or angiotensin-2 receptor blockers did not demonstrate a protective effect against the development of postoperative acute kidney injury (OR (95%CI) 0.89 (0.58-1.34); p = 0.567).

Prolonged Postoperative Vasoplegia in Pediatric Patients on Chronic Angiotensin II Blocker Treatment

Prolonged postoperative vasoplegia is known to occur following cardiac surgery in patients on chronic angiotensin II receptor blocker (ARB) treatment in adults. The perioperative management of these drugs in the pediatric population is not well described and here we would like to highlight this fact. While ARBs are increasingly used in children and adolescents with hypertension, there is lack of data to guide optimal pre-surgical management in the pediatric age group. We report two cases of prolonged vasoplegia following cardiopulmonary bypass occurring in adolescent patients on chronic ARB therapy and the importance of cessation of these drugs preoperatively.

Epidemiology, outcomes, and management of acute kidney injury in the vascular surgery patient

OBJECTIVE

Conventional clinical wisdom has often been nihilistic regarding the prevention and management of acute kidney injury (AKI), despite its being a frequent and morbid complication associated with both increased mortality and cost. Recent developments have shown that AKI is not inevitable and that changes in management of patients can reduce both the incidence and morbidity of perioperative AKI. The purpose of this narrative review was to review the epidemiology and outcomes of AKI in patients undergoing vascular surgery using current consensus definitions, to discuss some of the novel emerging risk stratification and prevention techniques relevant to the vascular surgery patient, and to describe a standardized perioperative pathway for the prevention of AKI after vascular surgery.

METHODS

We performed a critical review of the literature on AKI in the vascular surgery patient using the PubMed and MEDLINE databases and Google Scholar through September 2017 using web-based search engines. We also searched the guidelines and publications available online from the organizations Kidney Disease: Improving Global Outcomes and the Acute Dialysis Quality Initiative. The search terms used included acute kidney injury, AKI, epidemiology, outcomes, prevention, therapy, and treatment.

RESULTS

The reported epidemiology and outcomes associated with AKI have been evolving since the publication of consensus criteria that allow accurate identification of mild and moderate AKI. The incidence of AKI after major vascular surgery using current criteria is as high as 49%, although there are significant differences, depending on the type of procedure performed. Many tools have become available to assess and to stratify the risk for AKI and to use that information to prevent AKI in the surgical patient. We describe a standardized clinical assessment and management pathway for vascular surgery patients, incorporating current risk assessment and preventive strategies to prevent AKI and to decrease its complications. Patients without any risk factors can be managed in a perioperative fast-track pathway. Those patients with positive risk factors are tested for kidney stress using the urinary biomarker TIMP-2•IGFBP7, and care is then stratified according to the result. Management follows current Kidney Disease: Improving Global Outcomes guidelines.

CONCLUSIONS

AKI is a common postoperative complication among vascular surgery patients and has a significant impact on morbidity, mortality, and cost. Preoperative risk assessment and optimal perioperative management guided by that risk assessment can minimize the consequences associated with postoperative AKI. Adherence to a standardized perioperative pathway designed to reduce risk of AKI after major vascular surgery offers a promising clinical approach to mitigate the incidence and severity of this challenging clinical problem.

Prospective Randomized Evaluation of Preoperative Angiotensin-Converting Enzyme Inhibition (PREOP-ACEI)

BACKGROUND

Intraoperative hypotension is associated with an increased risk of end organ damage and death. The transient preoperative interruption of angiotensinconverting enzyme inhibitor (ACEI) therapy prior to cardiac and vascular surgeries decreases the occurrence of intraoperative hypotension.

OBJECTIVE

We sought to compare the effect of two protocols for preoperative ACEI management on the risk of intraoperative hypotension among patients undergoing noncardiac, nonvascular surgeries.

DESIGN

Prospective, randomized study.

SETTING

Midwestern urban 489-bed academic medical center.

PATIENTS

Patients taking an ACEI for at least six weeks preoperatively were considered for inclusion.

INTERVENTIONS

Randomization of the final preoperative ACEI dose to omission (n = 137) or continuation (n = 138).

MEASUREMENTS

The primary outcome was intraoperative hypotension, which was defined as any systolic blood pressure (SBP) < 80 mm Hg. Postoperative hypotensive (SBP < 90 mm Hg) and hypertensive (SBP >> 180 mm Hg) episodes were also recorded. Outcomes were compared using Fisher's exact test.

RESULTS

Intraoperative hypotension occurred less frequently in the omission group (76 of 137 [55%]) than in the continuation group (95 of 138 [69%]) (RR: 0.81, 95% CI: 0.67 to 0.97, P = .03, NNH 7.5). Postoperative hypotensive events were also less frequent in the ACEI omission group (RR: 0.49, 95% CI: 0.28 to 0.86, P = .02) than in the continuation group. However, postoperative hypertensive events were more frequent in the omission group than in the continuation group (RR: 1.95, 95%: CI: 1.14 to 3.34, P = .01).

CONCLUSIONS

The transient preoperative interruption of ACEI therapy is associated with a decreased risk of intraoperative hypotension.

REGISTRATION

ClinicalTrials.gov: NCT01669434.

New antihypertensive medications and clinical implications

Hypertension remains a global public health issue and is a leading preventable risk factor for many causes of mortality and morbidity. Although it is generally managed as an outpatient chronic disease, anaesthetists will inevitably encounter patients with hypertension, ranging from undiagnosed asymptomatic to chronic forms with end-organ damage(s). An understanding of perioperative management of anti-hypertensive pharmacotherapy is crucial. Although many drugs are familiar, new drug groups that have relevance for blood pressure control and perioperative care have evolved in recent years. This article also describes new antihypertensive agents currently available or under development that could impact perioperative management.

Losartan does not decrease renal oxygenation and norepinephrine effects in rats after resuscitated hemorrhage

Renin-angiotensin-system blockers are thought to increase the risk of acute kidney injury after surgery and hemorrhage. We found that losartan does not cause renal cortical hypoxia after hemorrhage in rats because of decreased renal vascular resistance, but we did not evaluate resuscitation. We aimed to study losartan's effect on renal cortical and medullary oxygenation, as well as norepinephrine's vasopressor effect in a model of resuscitated hemorrhage. After 7 days of losartan (60 mg·kg^-1·day^-1) or control treatment, male Wistar rats were hemorrhaged 20% of their blood volume and resuscitated with Ringer's acetate. Mean arterial pressure, renal blood flow, and kidney tissue oxygenation were measured at baseline and after resuscitation. Finally, the effect of norepinephrine on mean arterial pressure and renal blood flow was investigated. As expected, losartan lowered mean arterial pressure but not renal blood flow. Losartan did not affect renal oxygen consumption and oxygen tension. Mean arterial pressure and renal blood flow were lower after resuscitated hemorrhage. A smaller increase of renal vascular resistance in the losartan group translated to a smaller decrease in cortical oxygen tension, but no significant difference was seen in medullary oxygen tension, either between groups or after hemorrhage. The effect of norepinephrine on mean arterial pressure and renal blood flow was similar in control- and losartan-treated rats. Losartan does not decrease renal oxygenation after resuscitated hemorrhage because of a smaller increase in renal vascular resistance. Further, losartan does not decrease the efficiency of norepinephrine as a vasopressor, indicating that blood pressure may be managed effectively during losartan treatment.

Perioperative management of angiotensin-converting enzyme inhibitors and/or angiotensin receptor blockers: a survey of perioperative medicine practitioners

Background

Angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) are the most commonly prescribed antihypertensive medications in higher-risk surgical patients. However, there is no clinical consensus on their use in the perioperative period, in part, due to an inconsistent evidence-base. To help inform the design of a large multi-centre randomized controlled trial (ISRCTN17251494), we undertook a questionnaire-based survey exploring variability in ACEi/ARB prescribing in perioperative practice.

Methods

The online survey included perioperative scenarios to examine how consistent respondents were with their stated routine preoperative practice. Clinicians with an academic interest in perioperative medicine were primarily targeted between July and September 2017. STROBE guidelines for observational research and ANZCA Trials Group Survey Reporting recommendations were adhered to.

Results

194 responses were received, primarily from clinicians practicing in the UK. A similar minority of respondents continue ACEi (n = 57; 30%) and ARBs (n = 62; 32%) throughout the perioperative period. However, timing of preoperative cessation was highly variable, and rarely influenced by the pharmacokinetics of individual ACE-i/ARBs. Respondents’ stated routine practice was frequently misaligned with their management of common pre- and postoperative scenarios involving continuation or restarting ACE-i/ARBs.

Discussion

This survey highlights many inconsistencies amongst clinicians’ practice in perioperative ACE-i/ARB management. Studies designed to reveal an enhanced understanding of perioperative mechanisms at play, coupled with randomised controlled trials, are required to rationally inform the clinical management of ACE-i/ARBs in patients most at risk of postoperative morbidity.

Intraoperative hypotension and the risk of postoperative adverse outcomes: a systematic review

BACKGROUND

Intraoperative hypotension is a common side effect of general anaesthesia and might lead to inadequate organ perfusion. It is unclear to what extent hypotension during noncardiac surgery is associated with unfavourable outcomes.

METHODS

We conducted a systematic search in PubMed, Embase, Web of Science, and CINAHL, and classified the quality of retrieved articles according to predefined adapted STROBE and CONSORT criteria. Reported strengths of associations from high-quality studies were classified into end-organ specific injury risks, such as acute kidney injury, myocardial injury, and stroke, and overall organ injury risks for various arterial blood pressure thresholds.

RESULTS

We present an overview of 42 articles on reported associations between various absolute and relative intraoperative hypotension definitions and their associations with postoperative adverse outcomes after noncardiac surgery. Elevated risks of end-organ injury were reported for prolonged exposure (≥10 min) to mean arterial pressures <80 mm Hg and for shorter durations <70 mm Hg. Reported risks increase with increased durations for mean arterial pressures <65-60 mm Hg or for any exposure <55-50 mm Hg.

CONCLUSIONS

The reported associations suggest that organ injury might occur when mean arterial pressure decreases <80 mm Hg for ≥10 min, and that this risk increases with blood pressures becoming progressively lower. Given the retrospective observational design of the studies reviewed, reflected by large variability in patient characteristics, hypotension definitions and outcomes, solid conclusions on which blood pressures under which circumstances are truly too low cannot be drawn. We provide recommendations for the design of future studies. CLINICAL REGISTRATION NUMBER: (PROSPERO ID). CRD42013005171.

Perioperative myocardial injury and the contribution of hypotension

Mortality in the month following surgery is about 1000 times greater than anesthesia-related intraoperative mortality, and myocardial injury appears to be the leading cause. There is currently no known safe prophylaxis for postoperative myocardial injury, but there are strong associations among hypotension and myocardial injury, renal injury, and death. During surgery, the harm threshold is a mean arterial pressure of about 65 mmHg. In critical care units, the threshold appears to be considerably greater, perhaps 90 mmHg. The threshold triggering injury on surgical wards remains unclear but may be in between. Much of the association between hypotension and serious complications surely results from residual confounding, but sparse randomized data suggest that at least some harm can be prevented by intervening to limit hypotension. Reducing hypotension may therefore improve perioperative outcomes.

Association of renin angiotensin antagonists with adverse perioperative events in patients undergoing elective orthopaedic surgery: a case-control study

BACKGROUND

Renin angiotensin antagonists (RAA) may block protective vasopressor responses during surgery. Evidence linking RAA with intraoperative hypotension and perioperative adverse events is conflicting.

AIM

To compare the incidence of intraoperative hypotension and adverse events between patients receiving or not receiving RAA.

METHODS

This is a retrospective case-control study of 258 consecutive patients who underwent elective total knee or hip replacement between 1 January 2013 and 31 August 2016 and who were chronically prescribed a single blood pressure-lowering agent up to the time of surgery. Primary outcome measures were differences between patients receiving RAA (cases; n = 129) and patients receiving non-RAA medications (controls; n = 129) in incidence of intraoperative hypotension (systolic blood pressure <90 mmHg), perioperative acute kidney injury (AKI, >30% increase in serum creatinine from baseline on Day 1 post-operatively) and new onset major adverse cardiac or cerebrovascular events (MACCE) or in-hospital death over 72 h post-operatively.

RESULTS

Patients receiving RAA had significantly higher preoperative systolic blood pressure, greater prevalence of hypertension and chronic kidney disease, lower prevalence of ischaemic heart disease and lower cardiac risk compared to controls. Age, gender, type of operation, operative fitness, mode and duration of anaesthesia and prevalence of other types of cardiovascular disease, dyslipidaemia and diabetes were similar between groups. Compared to controls, patients receiving RAA had higher incidence of intraoperative hypotension (76.0 vs 45.9%, P < 0.001), AKI (11.6 vs 1.6%, P = 0.002) and MACCE (6.2 vs 0%, P = 0.007), with all adverse events associated with intraoperative hypotension.

CONCLUSION

This study provides further observational evidence of RAA-induced harm in patients undergoing elective surgery, although determining benefits and harms of preoperative withdrawal of RRA requires prospective randomised trials.

Postoperative Remote Automated Monitoring: Need for and State of the Science

Worldwide, more than 230 million adults have major noncardiac surgery each year. Although surgery can improve quality and duration of life, it can also precipitate major complications. Moreover, a substantial proportion of deaths occur after discharge. Current systems for monitoring patients postoperatively, on surgical wards and after transition to home, are inadequate. On the surgical ward, vital signs evaluation usually occurs only every 4-8 hours. Reduced in-hospital ward monitoring, followed by no vital signs monitoring at home, leads to thousands of cases of undetected/delayed detection of hemodynamic compromise. In this article we review work to date on postoperative remote automated monitoring on surgical wards and strategy for advancing this field. Key considerations for overcoming current barriers to implementing remote automated monitoring in Canada are also presented.

Influence of on-going treatment with angiotensin-converting enzyme inhibitor or angiotensin receptor blocker on the outcome of patients treated with intravenous rt-PA for ischemic stroke

BACKGROUND

Many patients who receive intravenous (i.v.) recombinant tissue-plasminogen activator (rt-PA) for acute cerebral ischemia were under angiotensin-converting enzyme inhibitors (ACE-Is) or angiotensin receptor blockers (ARBs) at stroke onset. ACE-Is and ARBs have neuroprotective properties in animal models.

OBJECTIVE

To evaluate whether the 3-month outcome of patients treated with i.v. rt-PA for cerebral ischemia was influenced by on-going therapy with ACE-Is or ARBs.

METHOD

This study was observational, conducted in two prospective registries of stroke patients treated with i.v. rt-PA. We evaluated outcomes with the modified Rankin scale and symptomatic intracranial hemorrhages (s-ICH) according to the ECASS2 criteria. We compared outcomes between patients with and without ACE-Is/ARBs according to the modified Rankin scale (mRS) at month 3, using logistic regression analyses adjusted on propensity scores, and propensity-matched analyses.

RESULTS

Of 1803 patients, 455 (25.2%) were under ACE-Is (259), ARBs (188) or both (8). At 3 months, patients under ACE-Is or ARBs were more likely to have an mRS 0-1, but did not differ for mRS 0-2, s-ICH and death. After adjustment on propensity scores, the association between ACE-Is/ARBs and mRS 0-1 disappeared. The propensity-matched analysis, performed in 397 pairs of patients, found no difference in outcomes between patients with and without ACE-Is or ARBs.

CONCLUSION

In patients treated by intravenous thrombolytic therapy for ischemic stroke, on-going treatment with ACE-Is or ARBs does not influence on outcomes after adjustment on baseline characteristics and propensity scores.

Consequences of continuing renin angiotensin aldosterone system antagonists in the preoperative period: a systematic review and meta-analysis

Background

Patients who use angiotensin-converting enzyme inhibitors (ACEIs)/angiotensin II receptor blockers (ARBs) are prone to developing side effects like hypotension and even refractory hypotension during anesthesia use, and whether ACEIs/ARBs should be continued or discontinued in such patients remains debatable. The present systematic review and meta-analysis was conducted to clarify the consequences of continuing or withholding these drugs, especially with regards to the incidence of intraoperative hypotension, in patients who continue to use ACEIs/ARBs on the day of their scheduled surgery.

Methods

Studies with data pertinent to the incidence of intraoperative hypotension during anesthesia use in patients who continued the use of ACEIs/ARBs on the day of their scheduled surgery were considered for inclusion.

Results

Thirteen studies reporting on the incidences of intraoperative hypotension between patients who continued receiving ACEIs/ARBs and those who did not on the day of their surgical procedure were included. The pooled effects showed that hypotension during anesthesia was more likely to develop in patients who continued to take ACEIs/ARBs when compared to those who did not (RR = 1.41, 95% CI: 1.21–1.64). However, there were no significant differences between these groups of patients with regards to postoperative complications including ST-T abnormalities, myocardial injury, myocardial infarction, stroke, major adverse cardiac events, acute kidney injury, or death (RR = 1.25, 95% CI: 0.76–2.04). The differences remained similar in subgroup analyses and sensitivity analyses.

Conclusions

No sufficient available evidence to recommend discontinuing ACEIs/ARBs on the day of surgery was found in this literature review and meta-analysis. However, anesthetists should be cautious about the risk for intraoperative hypotension in patients chronically receiving ACEIs/ARBs, and should know how to treat it effectively.

Preoperative Hypertension

PURPOSE OF REVIEW

This review will examine the implications for perioperative management of new hypertension guidelines and place these in the context of findings from recent large observational studies.

RECENT FINDINGS

Recent hypertension guidelines highlight the role of ambulatory blood pressure measurement with the implication that isolated preoperative blood pressure measurements are of limited value. There is emerging evidence from large observational studies that both preoperative and intraoperative hypotension are associated with increased risk. It is not clear if this is a particular concern for hypertensive patients.

SUMMARY

Assessment of the hypertensive surgical patient should include blood pressure measurements taken using the correct technique. Preoperative blood pressures of less than 180/100 mmHg are not grounds for deferring surgery in the absence of active comorbid disease. Evidence to guide the perioperative management of patients with higher pressures is scanty and decisions should be made on a case-by-case basis.

Period-dependent Associations between Hypotension during and for Four Days after Noncardiac Surgery and a Composite of Myocardial Infarction and Death

Background

The relative contributions of intraoperative and postoperative hypotension to perioperative morbidity remain unclear. We determined the association between hypotension and a composite of 30-day myocardial infarction and death over three periods: (1) intraoperative, (2) remaining day of surgery, and (3) during the initial four postoperative days.

Methods

This was a substudy of POISE-2, a 10,010-patient factorial-randomized trial of aspirin and clonidine for prevention of myocardial infarction. Clinically important hypotension was defined as systolic blood pressure less than 90 mmHg requiring treatment. Minutes of hypotension was the exposure variable intraoperatively and for the remaining day of surgery, whereas hypotension status was treated as binary variable for postoperative days 1 to 4. We estimated the average relative effect of hypotension across components of the composite using a distinct effect generalized estimating model, adjusting for hypotension during earlier periods.

Results

Among 9,765 patients, 42% experienced hypotension, 590 (6.0%) had an infarction, and 116 (1.2%) died within 30 days of surgery. Intraoperatively, the estimated average relative effect across myocardial infarction and mortality was 1.08 (98.3% CI, 1.03, 1.12; P &lt; 0.001) per 10-min increase in hypotension duration. For the remaining day of surgery, the odds ratio was 1.03 (98.3% CI, 1.01, 1.05; P &lt; 0.001) per 10-min increase in hypotension duration. The average relative effect odds ratio was 2.83 (98.3% CI, 1.26, 6.35; P = 0.002) in patients with hypotension during the subsequent four days of hospitalization.

Conclusions

Clinically important hypotension—a potentially modifiable exposure—was significantly associated with a composite of myocardial infarction and death during each of three perioperative periods, even after adjustment for previous hypotension.

Update in perioperative medicine: practice changing evidence published in 2016

This summary reviews 18 key articles published in 2016 which have significant practice implications for the perioperative medical care of surgical patients. Due to the multi-disciplinary nature of the practice of perioperative medicine, important new evidence is published in journals representing a variety of medical and surgical specialties. Keeping current with the evidence that drives best practice in perioperative medicine is therefore challenging. We set out to identify, critically review, and summarize key evidence which has the most potential for practice change. We integrated the new evidence into the existing body of medical knowledge and identified practical implications for real world patient care. The articles address issues related to anticoagulation, transfusion threshold, immunosuppressive medications, postoperative delirium, myocardial injury after noncardiac surgery, postoperative pain management, perioperative management of antihypertensives, perioperative fasting, and perioperative diabetic control.

Hypotensive Transfusion Reaction Treated With Vasopressin in a Patient Taking an Angiotensin-Converting Enzyme Inhibitor: A Case Report

Hypotensive transfusion reactions, which account for almost 3% of all transfusion reactions, are associated with patients treated with angiotensin-converting enzyme inhibitors. The current hypothesis suggests that they are caused by bradykinin-induced vasodilation in the absence of allergic, hemolytic, or septic mechanisms. The hypotension observed frequently is unresponsive to conventional therapy with catecholamines. The suggested intraoperative management includes cessation of transfusion and washing red blood cells before blood replacement. We present a patient experiencing a severe intraoperative hypotensive transfusion reaction, unresponsive to epinephrine and norepinephrine, in whom we were able to restore blood pressure and continue the transfusion of blood and plasma by infusing vasopressin.

Role of vasopressin in current anesthetic practice

Arginine vasopressin (AVP), also known as antidiuretic hormone, is a peptide endogenously secreted by the posterior pituitary in response to hyperosmolar plasma or systemic hypoperfusion states. When administered intravenously, it causes an intense peripheral vasoconstriction through stimulation of V₁ receptors on the vascular smooth muscle. Patients in refractory shock associated with severe sepsis, cardiogenic or vasodilatory shock, or cardiopulmonary bypass have inappropriately low plasma levels of AVP (‘relative vasopressin deficiency’) and supersensitivity to exogenously-administered AVP. Low doses of AVP and its synthetic analog terlipressin can restore vasomotor tone in conditions that are resistant to catecholamines, with preservation of renal blood flow and urine output. They are also useful in the treatment of refractory arterial hypotension in patients chronically treated with renin-angiotensin system inhibitors, cardiac arrest, or bleeding esophageal varices. In the perioperative setting, they represent attractive adjunct vasopressors in advanced shock states that are unresponsive to conventional therapeutic strategies.