Relationship Between Preoperative Evaluation Blood Pressure and Preinduction Blood Pressure

Factors Influencing Preoperative Blood Pressure Fluctuations in Patients Undergoing Elective Surgery: A Retrospective Observational Study

Purpose

To investigate the factors influencing preoperative blood pressure fluctuations in patients undergoing elective surgery.

Patients and Methods

This retrospective observational study included 776 patients who underwent elective surgery between January and October 2021. Preoperative blood pressure fluctuations were defined las a systolic or diastolic change exceeding 20% compared to baseline measurements taken one day prior to surgery. Patients were divided into two groups: the elevated blood pressure group (n=328) and the non-fluctuating group (n=448). Multivariate logistic regression analysis was employed to identify independent risk factors associated with blood pressure fluctuations.

Results

Among the 776 patients (335 males and 441 females), the average systolic blood pressure increased by 12.98 ± 19.33 mmHg, and diastolic blood pressure increased by 6.67 ± 13.20 mmHg on the day of surgery compared to the previous day. Preoperative blood pressure fluctuations exceeding 20% were observed in 42.27% of patients. Multivariate logistic regression revealed that older age (OR = 1.021; 95% CI: 1.007-1.035; P = 0.003), preoperative hypertension (OR = 1.785; 95% CI: 1.142-2.807; P = 0.011), and shorter sleep duration the night before surgery (OR = 0.835; 95% CI: 0.747-0.932; P = 0.001) were independent risk factors for blood pressure fluctuations.

Conclusion

Significant increases in preoperative blood pressure were observed upon patient entry into the operating room. Older age, preoperative hypertension, and inadequate sleep duration were identified as independent risk factors for blood pressure fluctuations. These findings underscore the need for targeted preoperative interventions to minimize blood pressure variability, particularly in elderly and hypertensive patients with inadequate sleep duration.

Effect of different intraoperative blood pressure regulation levels on postoperative myocardial injury in patients undergoing radical mastectomy for breast cancer after receiving neoadjuvant chemotherapy: a study protocol for a randomised controlled trial

INTRODUCTION

For patients with breast cancer receiving preoperative neoadjuvant chemotherapy with anthracyclines, there is an increased risk of postoperative myocardial injury due to the cardiotoxicity of the chemotherapeutic agents. The optimal intraoperative blood pressure regulation regimen for these patients is unclear. This study is being conducted to determine whether targeting mean arterial pressure (MAP) to 100%-120% of the patient's baseline blood pressure reduces the incidence of myocardial injury after non-cardiac surgery (MINS) compared with targeting MAP to 80%-100%. MINS is defined as elevated cardiac troponin levels within 30 days after non-cardiac surgery with or without clinical and electrocardiographic signs of cardiac ischaemia.

METHODS AND ANALYSIS

The study is a single-centre, single-blind, prospective randomised controlled trial. It is expected to enrol 166 subjects receiving neoadjuvant chemotherapy with anthracyclines, between the ages of 40 and 75 years, scheduled for radical mastectomy. Participants will be randomised 1:1 to a lower-level group:intraoperative MAP control at 80%-100% of baseline values or a higher-level group:intraoperative MAP control at 100%-120% of baseline values. The primary outcome is defined by the incidence of MINS at 6-8 hours, 24 hours and 48 hours postoperatively. The secondary outcomes are heart-type free fatty acid-binding protein values at 1-2 hours, 6-8 hours and 24 hours postoperatively; the incidence of acute kidney injury within 48 hours postoperatively; the Quality of Recovery-15 score at 24 hours, 48 hours postoperatively; post-anaesthesia care unit length of stay; other postoperative cardiovascular complications; the number of times rescue analgesia and antiemetics are required; the time to first ambulation and length of postoperative hospitalisation.

ETHICS AND DISSEMINATION

This study involves the participation of human subjects and has received approval from the Clinical Trial Ethics Committee at The Affiliated Lianyungang Hospital of Xuzhou Medical University (approval number: KY-20230915001). Study results will be presented at scientific meetings and in scientific publications.

TRIAL REGISTRATION NUMBER

ChiCTR2300077675.

Impact of Preanesthetic Blood Pressure Deviations on 30-Day Postoperative Mortality in Non-Cardiac Surgery Patients

BACKGROUND

Blood pressure readings taken before anesthesia often influence the decision to delay or cancel elective surgeries. However, the implications of these specific blood pressure values, especially how they compare to baseline, on postoperative in-hospital 30-day mortality remain underexplored. This research aimed to examine the effect of discrepancies between the baseline blood pressure evaluated in the ward a day before surgery, and the blood pressure observed just before the administration of anesthesia, on the postoperative mortality risks.

METHODS

The study encompassed 60,534 adults scheduled for non-cardiac surgeries at a tertiary care center in Seoul, Korea. Baseline blood pressure was calculated as the mean of the blood pressure readings taken within 24 hours prior to surgery. The preanesthetic blood pressure was the blood pressure measured right before the administration of anesthesia. We focused on in-hospital 30-day mortality as the primary outcome.

RESULTS

Our research revealed that a lower preanesthetic systolic or mean blood pressure that deviates by 20 mmHg or more from baseline significantly increased the risk of 30-day mortality. This association was particularly pronounced in individuals with a history of hypertension and those aged 65 and above. Higher preanesthetic blood pressure was not significantly associated with an increased risk of 30-day mortality.

CONCLUSION

We found that a lower preanesthetic blood pressure compared to baseline significantly increased the 30-day postoperative mortality risk, whereas a higher preanesthetic blood pressure did not. Our study emphasizes the critical importance of accounting for variations in both baseline and preanesthetic blood pressure when assessing surgical risks and outcomes.

The relationship between preoperative blood pressure during anesthetic examinations and pre-intubation blood pressure

BACKGROUND

There have been few reports showing the relationship between blood pressure (BP) measured at clinics preoperatively and BP measured before anesthetic intubation/induction. The purpose of this study was to examine the relationship between BP measured at different times and settings preoperatively and BP measured before intubation/induction.

METHODS

A total of 182 patients who underwent general anesthesia between March 2021 and April 2022 in a university hospital were examined. In addition to self-reported BP asked on an anesthetic examination sheet completed by each patient, BPs were measured three times, before, during, and after preoperative examination by the anesthesiologist. The derived parameter was compared with BP measured before intubation at the time of general anesthesia induction.

RESULTS

The systolic BP in the intra-examination period had the most significant correlation with pre-intubation systolic BP (r = 0.5230, p < 0.0001, 95% CI = 0.4050 to 0.6238). On Bland-Altman analysis, the intra-examination systolic BP seemed to be similar and showed better agreement with pre-intubation systolic BP than other measured BPs, with a mean bias of 2.2 mmHg and the narrowest 95% limits of agreement (-33.7 to + 38.1 mmHg).

CONCLUSIONS

The preoperative systolic BP value measured during the examination by the anesthesiologist was found to be closely related to pre-intubation systolic BP measured in the operating room. Higher BP during the preoperative examination may be a result of anxiety-induced stress or white-coat hypertension. Measuring BP during the anesthesiologist's examination may be useful for predicting hypertension in the pre-intubation period.

Investigation of the Optimum Baseline Blood Pressure for Spinal Anesthesia to Guide Vasopressor Management for Elective Cesarean Delivery: A Case-Control Design

BACKGROUND

Current guidelines recommend prophylactic vasopressor administration during spinal anesthesia for cesarean delivery to maintain intraoperative blood pressure above 90% of the baseline value. We sought to determine the optimum baseline mean arterial pressure (MAP) reading to guide the management of spinal hypotension.

METHODS

We performed a secondary analysis of data collected from normotensive patients presenting for elective cesarean delivery in a tertiary care institution from October 2018 to August 2020. We compared the magnitude of hypotension in patients who reported nausea versus those who did not, using a case-control design. Baseline MAPs at last office visit, morning of surgery, or operating room (pre-spinal) were determined. We calculated the duration and degree of hypotension using the area under the curve (AUC) when the MAP of the respective patient was below 90% of each baseline.

RESULTS

The patients who experienced nausea (n=45) had longer and more profound periods of hypotension than those who did not develop nausea (n=240). A comparison of AUC using MAP baseline at the last office visit or on the morning of surgery showed a statistically significant between-group difference, P=0.02, and P=0.005, respectively, and no significant between-group difference when 90% of the MAP baseline in the operating room was used.

CONCLUSIONS

Patients had the highest preoperative MAP in the operating room and the AUC was similar for those with and without nausea when the pre-spinal MAP baseline was used. Therefore, maintaining higher intraoperative blood pressure using individual pre-spinal MAP as baseline should reduce intraoperative maternal nausea.

Intraoperative Hypotension Prediction—A Proactive Perioperative Hemodynamic Management—A Literature Review

Intraoperative hypotension (IH) is a frequent phenomenon affecting a substantial number of patients undergoing general anesthesia. The occurrence of IH is related to significant perioperative complications, including kidney failure, myocardial injury, and even increased mortality. Despite advanced hemodynamic monitoring and protocols utilizing goal directed therapy, our management is still reactive; we intervene when the episode of hypotension has already occurred. This literature review evaluated the Hypotension Prediction Index (HPI), which is designed to predict and reduce the incidence of IH. The HPI algorithm is based on a machine learning algorithm that analyzes the arterial pressure waveform as an input and the occurrence of hypotension with MAP <65 mmHg for at least 1 min as an output. There are several studies, both retrospective and prospective, showing a significant reduction in IH episodes with the use of the HPI algorithm. However, the level of evidence on the use of HPI remains very low, and further studies are needed to show the benefits of this algorithm on perioperative outcomes.

Effect of personalized perioperative blood pressure management on postoperative complications and mortality in high-risk patients having major abdominal surgery: protocol for a multicenter randomized trial (IMPROVE-multi)

BACKGROUND

Intraoperative hypotension is common in patients having non-cardiac surgery and is associated with serious complications and death. However, optimal intraoperative blood pressures for individual patients remain unknown. We therefore aim to test the hypothesis that personalized perioperative blood pressure management-based on preoperative automated blood pressure monitoring-reduces the incidence of a composite outcome of acute kidney injury, acute myocardial injury, non-fatal cardiac arrest, and death within 7 days after surgery compared to routine blood pressure management in high-risk patients having major abdominal surgery.

METHODS

IMPROVE-multi is a multicenter randomized trial in 1272 high-risk patients having elective major abdominal surgery that we plan to conduct at 16 German university medical centers. Preoperative automated blood pressure monitoring using upper arm cuff oscillometry will be performed in all patients for one night to obtain the mean of the nighttime mean arterial pressures. Patients will then be randomized either to personalized blood pressure management or to routine blood pressure management. In patients assigned to personalized management, intraoperative mean arterial pressure will be maintained at least at the mean of the nighttime mean arterial pressures. In patients assigned to routine management, intraoperative blood pressure will be managed per routine. The primary outcome will be a composite of acute kidney injury, acute myocardial injury, non-fatal cardiac arrest, and death within 7 days after surgery.

DISCUSSION

Our trial will determine whether personalized perioperative blood pressure management reduces the incidence of major postoperative complications and death within 7 days after surgery compared to routine blood pressure management in high-risk patients having major abdominal surgery.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05416944. Registered on June 14, 2022.

Intraoperative Hypotension and Myocardial Injury After Noncardiac Surgery in Adults With or Without Chronic Hypertension: A Retrospective Cohort Analysis

BACKGROUND

The risk of myocardial injury progressively increases at intraoperative mean arterial pressures (MAPs) ≤65 mm Hg. Higher pressures might be required in chronically hypertensive patients. We aimed to test the hypothesis that the harm threshold is higher in patients with chronic hypertension than in normotensive patients.

METHODS

We conducted a single-center retrospective cohort analysis of adults >45 years old who had noncardiac surgery between 2010 and 2018 and scheduled, rather than symptom-driven, postoperative troponin measurements. The MAP thresholds under which risk started to increase were compared between patients with chronic hypertension (baseline MAP ≥110 mm Hg) and normotensive patients (baseline MAP <110 mm Hg). The primary outcome was a composite of in-hospital mortality and myocardial injury within 30 days, defined by any postoperative 4th-generation troponin T measurement ≥0.03 ng/mL apparently due to cardiac ischemia. Multivariable logistic regression and moving average smoothing methods were used to evaluate confounder-adjusted associations between the composite outcome and the lowest intraoperative MAP sustained for either 5 or 10 cumulative minutes, and whether the relationship depended on baseline pressure (normotensive versus hypertensive).

RESULTS

Among 4576 eligible surgeries, 2066 were assigned to the normotensive group with mean (standard deviation [SD]) baseline MAP of 100 (7) mm Hg, and 2510 were assigned to the hypertensive group with mean baseline MAP of 122 (10) mm Hg. The overall incidence of the composite outcome was 5.6% in normotensive and 6.0% in hypertensive patients ( P = .55). The relationship between intraoperative hypotension and the composite outcome was not found to depend on baseline MAP in a multivariable mixed effects logistic regression model. Furthermore, no statistical change points were found for either baseline MAP group.

CONCLUSIONS

Baseline blood pressure of the hypertensive patients was only moderately increased on average, and the event rate was low. Nonetheless, we were not able to demonstrate a difference in the harm threshold between normotensive and chronically hypertensive patients. Our results do not support the theory that hypertensive patients should be kept at higher intraoperative pressures than normotensive patients.

Preoperative Care for Cataract Surgery: The Society for Ambulatory Anesthesia Position Statement

Cataract surgeries are among the most common procedures requiring anesthesia care. Cataracts are a common cause of blindness. Surgery remains the only effective treatment of cataracts. Patients are often elderly with comorbidities. Most cataracts can be treated using topical or regional anesthesia with minimum or no sedation. There is minimal risk of adverse outcomes. There is general consensus that cataract surgery is extremely low risk, and the benefits of sight restoration and preservation are enormous. We present the Society for Ambulatory Anesthesia (SAMBA) position statement for preoperative care for cataract surgery.

Defining the awake baseline blood pressure in patients undergoing carotid endarterectomy

BACKGROUND

To minimize the incidence of intraoperative stroke following carotid endarterectomy (CEA) under general anesthesia, blood pressure (BP) is suggested to be maintained between "awake baseline" BP and 20% above. However, there is neither a widely accepted protocol nor a definition to determine this awake BP. In this study, we analyzed the BP during hospital admission in the days before CEA and propose a definition of how to determine awake BP.

METHODS

In our cohort of 1180 CEA-patients, all noninvasive BP measurements were retrospectively analyzed. BP was measured during preoperative outpatient screening (POS), the last three days before surgery at the ward and in the operating room (OR) directly before anesthesia. Primary outcome was the comparability of all these preoperative BP measurements. Secondary outcome was the comparability of preoperative BP measurements stratified for postoperative stroke within 30 days.

RESULTS

POS BP (148±22/80±12 mmHg [mean arterial pressure, MAP: 103±14 mmHg]) and the BP measured on the ward 3, 2, 1 days before surgery and on the day of surgery (146±25/77±13 [MAP: 100±15]), (142±23/76±13 [MAP: 98±15]), (145±23/76±12 [MAP: 99±14]) and (144±22/75±12 mmHg [MAP: 98±14]) were comparable (all P=NS). However, BP in the OR directly before anesthesia was higher, (163±27/88±15 mmHg [MAP: 117±18mmHg]) (P<0.01 vs. all other preoperative moments). A significant higher preinduction systolic BP and MAP was observed in patients suffering a stroke within 30 days compared to patients without (P=0.03 and 0.04 respectively).

CONCLUSIONS

Awake BP should be determined by averaging available BP values collected preoperatively on the ward and POS. BP measured in the OR directly before induction of anesthesia overestimates "awake" BP; and therefore, it should not be used.

Variation in perioperative cerebral and hemodynamic monitoring during carotid endarterectomy

BACKGROUND

Hemodynamic disturbances cause half of the perioperative strokes following carotid endarterectomy (CEA). Guidelines strongly recommend strict pre- and postoperative blood pressure (BP) monitoring in CEA patients, but do not provide firm practical recommendations. Although in the Netherlands 50 centres perform CEA, no national protocol on perioperative hemodynamic, and cerebral monitoring exists. To assess current monitoring policies of all Dutch CEA-centres, a national survey was conducted.

METHODS

Between May and July 2017 all 50 Dutch CEA-centres were invited to complete a 42-question survey addressing perioperative hemodynamic and cerebral monitoring during CEA. Nonresponders received a reminder after 1 and 2 months. By November 2017 the survey was completed by all centres.

RESULTS

Preoperative baseline BP was based on a single bilateral BP-measurement at the outpatient-clinic in the majority of centres (n = 28). In 43 centres (86%) pre-operative monitoring (transcranial Doppler (TCD, n = 6), electroencephalography (EEG, n = 11), or TCD + EEG (n = 26)) was performed as a baseline reference. Intraoperatively, large diversity for type of anaesthesia (general: 45 vs. local [LA]:5) and target systolic BP (>100 mm hg - 160 mm hg [n = 12], based on preoperative outpatient-clinic or admission BP [n = 18], other [n = 20]) was reported. Intraoperative cerebral monitoring included EEG + TCD (n = 28), EEG alone (n = 13), clinical neurological examination with LA (n = 5), near-infrared spectroscopy with stump pressure (n = 1), and none due to standard shunting (n = 3). Postoperatively, significant variation was reported in standard duration of admission at a recovery or high-care unit (range 3-48 hr, mean:12 hr), maximum accepted systolic BP (range >100 mm hg - 180 mm Hg [n = 32]), postoperative cerebral monitoring (standard TCD [n = 16], TCD on indication [n = 5] or none [n = 24]) and in timing of postoperative cerebral monitoring (range directly postoperative - 24 hr postoperative; median 3 hr).

CONCLUSIONS

In Dutch centres performing CEA the perioperative hemodynamic and cerebral monitoring policies are widely diverse. Diverse policies may theoretically lead to over- or under treatment. The results of this national audit may serve as the baseline dataset for development of a standardized and detailed (inter)national protocol on perioperative hemodynamic and cerebral monitoring during CEA.

Intravenously injected lidocaine or magnesium improves the quality of early recovery after laparoscopic cholecystectomy: A randomised controlled trial

BACKGROUND

Previous data show that lidocaine or magnesium has unique characteristics of stress inhibition and antiinflammation.

OBJECTIVE

We aimed to observe the effects of lidocaine or magnesium on the quality of recovery (QoR) after laparoscopic cholecystectomy.

DESIGN

Single-centre, prospective, randomised, double-blind study.

SETTING

The Affiliated Hospital of Xuzhou Medical University from March 2019 to October 2019.

PATIENTS

One hundred and fourteen patients scheduled for laparoscopic cholecystectomy.

INTERVENTION

The enrolled patients were randomly divided into three groups. Lidocaine (group L), magnesium sulphate (group M) or 0.9% saline (group C) was administered intravenously 10 min before induction.

MAIN OUTCOME MEASURES

The quality of recovery 15 (QoR-15) score, the Hospital Anxiety and Depression Scale (HADS), and the Numerical Rating Scale (NRS) score were selected. The usage of propofol and remifentanil, haemodynamic parameters, anaesthesia recovery parameters and adverse events were also evaluated.

RESULTS

The QoR-15 scores for group L (132.0) and group M (134.0) were 6 and 8 points higher than that of group C (126.0) on POD1 (postoperative day 1) (adjP < 0.05). However, the decrease of QoR-15 in Group L is less than the minimal clinically important difference (8).The NRS scores on POD1 in group C 3, were higher than other two groups (adjP < 0.05). The dosage of remifentanil in group L was lower than other two groups (adjP < 0.05).The physical independence of group L and group M and physical comfort of group M were improved compared with group C.

CONCLUSION

The results show that magnesium sulphate improved the QoR through improving physical comfort and physical independence in patients after laparoscopic cholecystectomy. However, lidocaine had limited effects on QoR under current conditions.

TRIAL REGISTRATION

ChiCTR1800019092 (www.chictr.org.cn).

CLINICAL TRIAL NUMBER AND REGISTRY URL

The study was registered in the Chinese Clinical Trials Register (ChiCTR1800019092) https://www.chictr.org.cn.

Selection of baseline blood pressure to guide management of hypotension during spinal anaesthesia for caesarean section

INTRODUCTION

Recommendations on vasopressor management during caesarean section under spinal anaesthesia suggest maintaining systolic arterial pressure ≥90% of an accurately measured baseline value. The baseline is often taken as the first reading in the operating room. We hypothesise that this reading may not reflect an accurate baseline value.

METHODS

A retrospective case note review of 300 non-hypertensive women undergoing caesarean section with neuraxial anaesthesia, including spinal anaesthesia for elective delivery (n=100), and spinal (n=100) and epidural top-up anaesthesia (n=100) for emergency delivery. Systolic arterial pressure values recorded at various time points between the last antenatal visit and the first blood pressure value recorded in the operating room were compared.

RESULTS

There was a stepwise and significant increase in systolic arterial pressure over three time points (last antenatal clinic, morning of surgery, operating room) before elective caesarean section (all P <0.001). In women having emergency caesarean under spinal anaesthesia, a stepwise increase over four time points (last antenatal clinic, first reading in labour, final reading in labour, operating room) was observed. A similar trend was seen over these time points for women having emergency caesarean under epidural top-up, although the systolic blood pressure did not rise during labour.

CONCLUSIONS

Using the initial blood pressure reading in the operating room as the baseline value may lead to unnecessary vasopressor use and hypertension. Prospective research is required to clarify which reading represents the most accurate baseline to maintain homeostasis and reduce the hypotensive sequelae of neuraxial anaesthesia for both the mother and fetus.

Effect of Phenylephrine and Ephedrine on Cerebral (Tissue) Oxygen Saturation During Carotid Endarterectomy (PEPPER): A Randomized Controlled Trial

Background

Short-acting vasopressor agents like phenylephrine or ephedrine can be used during carotid endarterectomy (CEA) to achieve adequate blood pressure (BP) to prevent periprocedural stroke by preserving the cerebral perfusion. Previous studies in healthy subjects showed that these vasopressors also affected the frontal lobe cerebral tissue oxygenation (rSO₂) with a decrease after administration of phenylephrine. This decrease is unwarranted in patients with jeopardized cerebral perfusion, like CEA patients. The study aimed to evaluate the impact of both phenylephrine and ephedrine on the rSO₂ during CEA.

Methods

In this double-blinded randomized controlled trial, 29 patients with symptomatic carotid artery stenosis underwent CEA under volatile general anesthesia in a tertiary referral medical center. Patients were preoperative allocated randomly (1:1) for receiving either phenylephrine (50 µg; n = 14) or ephedrine (5 mg; n = 15) in case intraoperative hypotension occurred, defined as a decreased mean arterial pressure (MAP) ≥ 20% compared to (awake) baseline. Intraoperative MAP was measured by an intra-arterial cannula placed in the radial artery. After administration, the MAP, cardiac output (CO), heart rate (HR), stroke volume, and rSO₂ both ipsilateral and contralateral were measured. The timeframe for data analysis was 120 s before, until 600 s after administration.

Results

Both phenylephrine (70 ± 9 to 101 ± 22 mmHg; p < 0.001; mean ± SD) and ephedrine (75 ± 11 mmHg to 122 ± 22 mmHg; p < 0.001) adequately restored MAP. After administration, HR did not change significantly over time, and CO increased 19% for both phenylephrine and ephedrine. rSO₂ ipsilateral and contralateral did not change significantly after administration at 300 and 600 s for either phenylephrine or ephedrine (phenylephrine 73%, 73%, 73% and 73%, 73%, 74%; ephedrine 72%, 73%, 73% and 75%, 74%, 74%).

Conclusions

Within this randomized prospective study, MAP correction by either phenylephrine or ephedrine showed to be equally effective in maintaining rSO₂ in patients who underwent CEA.

Clinical Trial Registration ClincalTrials.gov, NCT01451294.

[Perioperative blood pressure management : What is the optimal pressure?]

BACKGROUND

Measurement of blood pressure is part of standard monitoring procedures in anesthesia, in addition to the other vital parameters of heart frequency and peripheral oxygen saturation. In recent years the relevance of the duration and extent of perioperative episodes of hypotension for the occurrence of postoperative complications or even increased mortality have become the focus of scientific investigations.

OBJECTIVE

The aim of this review is to briefly recapitulate the physiological aspects of blood pressure and to describe the pathophysiology and risk factors of perioperative hypotension. It describes which potential organ damage can be caused by hypotension and discusses which perioperative blood pressure values are acceptable without harming the patient.

METHODS

Review and analysis of the currently available literature.

RESULTS

Perioperative hypotension is defined by either absolute systolic arterial pressure (SAP) or mean arterial pressure (MAP) thresholds and by relative blood pressure declines from an individual preoperative baseline value. For the definition of absolute and relative thresholds it needs to be considered that the ultimate target is an adequate perfusion pressure (and not the MAP) and that the preinduction blood pressure is a poor reflection of the patients' normal blood pressure profile. Risk factors for an intraoperative drop in blood pressure are advanced age, higher American Society of Anesthesiologists (ASA) status, low blood pressure prior to induction of anesthesia, the premedication, e.g. angiotensin-converting enzyme (ACE) inhibitors, the anesthesia technique (combination of general and epidural anesthesia) and emergency surgery. The lowest tolerable intraoperative blood pressure should be defined according to the individual patient's preoperative blood pressure and risk profile. Individual thresholds should be determined for the severity and duration of intraoperative hypotension. Empirically, MAP values <65 mm Hg and relative pressure declines of >20-30% are often recommended as thresholds. Below critical blood pressure values the risk of postoperative organ damage (myocardium, kidneys and central nervous system) and mortality increases with longer duration of hypotension. Older people and high-risk patients (e.g. patients in vascular surgery) have a poorer and shorter tolerance of low blood pressure. Postoperative organ complications can be minimized by maintenance of an adequate intraoperative blood pressure CONCLUSION: Anesthesiologists should avoid extensive and prolonged hypotension by timely interventions in order to improve the postoperative outcome of patients.

Automated Ambulatory Blood Pressure Measurements and Intraoperative Hypotension in Patients Having Noncardiac Surgery with General Anesthesia: A Prospective Observational Study

BACKGROUND

Normal blood pressure varies among individuals and over the circadian cycle. Preinduction blood pressure may not be representative of a patient's normal blood pressure profile and cannot give an indication of a patient's usual range of blood pressures. This study therefore aimed to determine the relationship between ambulatory mean arterial pressure and preinduction, postinduction, and intraoperative mean arterial pressures.

METHODS

Ambulatory (automated oscillometric measurements at 30-min intervals) and preinduction, postinduction, and intraoperative mean arterial pressures (1-min intervals) were prospectively measured and compared in 370 American Society of Anesthesiology physical status classification I or II patients aged 40 to 65 yr having elective noncardiac surgery with general anesthesia.

RESULTS

There was only a weak correlation between the first preinduction and mean daytime mean arterial pressure (r = 0.429, P < 0.001). The difference between the first preinduction and mean daytime mean arterial pressure varied considerably among individuals. In about two thirds of the patients, the lowest postinduction and intraoperative mean arterial pressures were lower than the lowest nighttime mean arterial pressure. The difference between the lowest nighttime mean arterial pressure and a mean arterial pressure of 65 mmHg varied considerably among individuals. The lowest nighttime mean arterial pressure was higher than 65 mmHg in 263 patients (71%).

CONCLUSIONS

Preinduction mean arterial pressure cannot be used as a surrogate for the normal daytime mean arterial pressure. The lowest postinduction and intraoperative mean arterial pressures are lower than the lowest nighttime mean arterial pressure in most patients.

Blood Pressure and End-tidal Carbon Dioxide Ranges during Aneurysm Occlusion and Neurologic Outcome after an Aneurysmal Subarachnoid Hemorrhage

EDITOR’S PERSPECTIVE

What We Already Know about This Topic

It remains unknown what end-tidal carbon dioxide and mean arterial pressure are optimal for surgical management of patients with an aneurysmal subarachnoid hemorrhage

What This Article Tells Us That Is New

The investigators retrospectively evaluated 1,099 patients who had endovascular coiling or surgical clipping for subarachnoid hemorrhages

There were no clinically important or statistical significant associations between either end-tidal carbon dioxide or mean arterial pressure thresholds and Glasgow Outcome Scale at discharge or three months

Other prognostic factors are more important than carbon dioxide and blood pressure, at least within the observed clinical ranges

Background

Hypocapnia, hypotension, and hypertension during aneurysm occlusion in patients with an aneurysmal subarachnoid hemorrhage may lead to a poor prognosis, but evidence for end-tidal carbon dioxide (ETco2) and mean arterial pressure (MAP) targets is lacking. Within the ranges of standardized treatment, the authors aimed to study the association between hypocapnia (Paco2 &lt; 35 mmHg), hypotension (MAP &lt; 80 mmHg), and hypertension (MAP &gt;100 mmHg) during general anesthesia for aneurysm occlusion and neurologic outcome.

Methods

This retrospective observational study included patients who underwent early aneurysm occlusion after an aneurysmal subarachnoid hemorrhage under general anesthesia. ETco2 and MAP were summarized per patient as the mean and time-weighted average area under the curve for various absolute (ETco2 &lt; 30, &lt; 35, &lt; 40, &lt; 45 mmHg; and MAP &lt; 60, &lt; 70, &lt; 80, &gt; 90, &gt; 100 mmHg) and relative thresholds (MAP &lt; 70%, &lt; 60%, &lt; 50%). Clinical outcome was assessed with the Glasgow Outcome Scale at discharge and at three months, as primary and secondary outcome measure, respectively.

Results

Endovascular coiling was performed in 578 patients, and 521 underwent neurosurgical clipping. Of these 1,099 patients, 447 (41%) had a poor neurologic outcome at discharge. None of the ETco2 and MAP ranges found within the current clinical setting were associated with a poor neurologic outcome at discharge, with an adjusted risk ratio for any ETco2 value less than 30 mmHg of 0.95 (95% CI, 0.81 to 1.10; P &lt; 0.496) and an adjusted risk ratio for any MAP less than 60 mmHg of 0.94 (95% CI, 0.78 to 1.14; P &lt; 0.530). These results were not influenced by preoperative neurologic condition, treatment modality and timing of the intervention. Comparable results were obtained for neurologic outcome at three months.

Conclusions

Within a standardized intraoperative treatment strategy in accordance with current clinical consensus, hypocapnia, hypotension, and hypertension during aneurysm occlusion were not found to be associated with a poor neurologic outcome at discharge in patients with an aneurysmal subarachnoid hemorrhage.

The prevalence of cardiovascular autonomic neuropathy and its influence on post induction hemodynamic variables in patients with and without diabetes; A prospective cohort study

Background

Cardiovascular autonomic neuropathy (CAN) is a known complication of diabetes, but is also diagnosed in patients without diabetes. CAN may be related to perioperative hemodynamic instability. Our objective was to investigate if patients with diabetes would have a higher prevalence of CAN compared to patients without diabetes undergoing surgery. We further studied its relation to changes in post-induction hemodynamic variables.

Methods

We prospectively included 82 adult patients, 55 with DM, 27 without DM, scheduled for major abdominal or cardiac surgery. Patients performed four autonomic function tests on the day before surgery. Primary outcomes were the prevalence of CAN and the relation between CAN and severe post-induction hypotension, defined as mean arterial pressure (MAP) < 50 mmHg or ≥ 50% decrease from baseline. Secondary outcomes were the relation between CAN, intraoperative hypotension, MAP < 65 mmHg for more than 13 minutes, and the use of vasopressor therapy.

Results

The prevalence of CAN in patients with or without DM was 71% versus 63%, (p = 0.437). CAN was not associated with severe post induction hypotension (CAN+ vs. CAN–: 21% vs. 19.2%, p = 0.819) nor with intraoperative hypotension (16% vs. 15%, p = 0.937). Patients with definite CAN received more norepinephrine in the perioperative period compared to patients with mild CAN or no CAN (0.07 mcg kg^-1 min^-1 (0.05–0.08) vs. 0.03 (0.01–0.07) vs. 0.02 (0.01–0.06) respectively, p = 0.001).

Conclusions

The majority of patients studied had mild to moderate CAN, regardless of the presence of DM. Assessing CAN before surgery did not identify patients at risk for post induction and intraoperative hypotension in our cohort.

Trial registration

Dutch Trial Registry (www.trialregister.nl) NTR4976.

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.