The relationship between pre‐operative hypertension and intra‐operative haemodynamic changes known to be associated with postoperative morbidity

Abstract

Hypertension is not consistently associated with postoperative cardiovascular morbidity and is therefore not considered a major peri-operative risk factor. However, hypertension may predispose to peri-operative haemodynamic changes known to be associated with peri-operative morbidity and mortality, such as intra-operative hypotension and tachycardia. The objective of this study was to determine whether pre-operative hypertension was independently associated with haemodynamic changes known to be associated with adverse peri-operative outcomes. We performed a five-day multicentre, prospective, observational cohort study which included all adult inpatients undergoing elective, non-cardiac, non-obstetric surgery. We recruited 343 patients of whom 164 (47.8%) were hypertensive. An intra-operative mean arterial pressure of < 55 mmHg occurred in 59 (18.2%) patients, of which 25 (42.4%) were hypertensive. Intra-operative tachycardia (heart rate> 100 beats.min ) occurred in 126 (38.9%) patients, of whom 61 (48.4%) were hypertensive. Multivariable logistic regression did not show an independent association between the stage of hypertension and either clinically significant hypotension or tachycardia, when controlled for ASA physical status, functional status, major surgery, duration of surgery or blood transfusion. There was no association between pre-operative hypertension and peri-operative haemodynamic changes known to be associated with major morbidity and mortality. These data, therefore, support the recommendation of the Joint Guidelines of the Association of Anaesthetists of Great Britain and Ireland (AAGBI) and the British Hypertension Society to proceed with elective surgery if a patient's blood pressure is < 180/110 mmHg.

Postoperative Hypertension: When Blood Pressure Cuff and Arterial Line Disagree

“…erative anxiety and should be managed accordingly. Taken together, in the absence of any obvious treatable causes of preoperative hypertension and assuming the patient is asymptomatic, it is likely safe to proceed with surgery for hypertensive patients with BP < 180/110 mmHg [9].…”

A multicentre prospective observational study of the prevalence of preoperative anaemia and iron deficiency in adult elective surgical patients in hospitals in Western Cape Province, South Africa

“…[3,11,17] Based on previous studies with a similar design, and known numbers of surgical cases at participating hospitals, we expected to recruit 500 patients. [18] Patients who had no Hb recorded were excluded from our study. Patients with missing iron study results were excluded from calculation of IDA, but included in calculations of the prevalence of anaemia.…”

Pre‐operative hypertension and intra‐operative hypotension

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Correspondence

Pre-operative hypertension and intra-operative hypotensionCrowther et al conclude that pre-operative hypertension is not associated with an increased risk of intra-operative hypotension [1]. However, several factors must be considered in order to reach this conclusion, and we invite the authors to comment on these.

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“…Wesselink's systematic review includes papers that have been available to read for a number of years [2], and it is likely that anaesthetists monitor and intervene in the haemodynamics of those with hypertension more aggressively than those without hypertension, especially in the setting of a clinical trial; the hypertensive group, for example, were administered significantly higher amounts of vasopressors intra-operatively. Moreover, anaesthetists might be less likely to record dangerously low blood pressures on the data-capture form; the authors acknowledge this as a limit of their study, but to what extent do they think that any considering the limited evidence to support them [1]. In order to address this question, we adopted a pragmatic study design, with the ability to include the known independent risk factors for adverse peri-operative outcomes in non-cardiac surgery, in the logistic regression model [2].…”