Mortality following noncardiac surgery assessed by the Saint Louis University Score (SLUScore) for hypotension: a retrospective observational cohort study

BACKGROUND

The Saint Louis University Score (SLUScore) was developed to quantify intraoperative blood pressure trajectories and their associated risk for adverse outcomes. This study examines the prevalence and severity of intraoperative hypotension described by the SLUScore and its relationship with 30-day mortality in surgical subtypes.

METHODS

This retrospective analysis of perioperative data included surgical cases performed between January 1, 2010, and December 31, 2020. The SLUScore is calculated from cumulative time-periods for which the mean arterial pressure is below a range of hypotensive thresholds. After calculating the SLUScore for each surgical procedure, we quantified the prevalence and severity of intraoperative hypotension for each surgical procedure and the association between intraoperative hypotension and 30-day mortality. We used binary logistic regression to quantify the potential contribution of intraoperative hypotension to mortality.

RESULTS

We analysed 490 982 cases (57.7% female; mean age 57 yr); 33.2% of cases had a SLUScore>0, a median SLUScore of 13 (inter-quartile range [IQR] 7-21), with 1.19% average mortality. The SLUScore was associated with mortality in 12/14 surgical groups. The increases in the odds ratio for death within 30 days of surgery per SLUScore increment were: all surgery types 3.5% (95% confidence interval [95% CI] 3.2-3.9); abdominal/transplant surgery 6% (95% CI 1.5-10.7); thoracic surgery1.5% (95% CI 1-3.3); vascular surgery 3.01% (95% CI 1.9-4.05); spine/neurosurgery 1.1% (95% CI 0.1-2.1); orthopaedic surgery 1.4% (95% CI 0.7-2.2); gynaecological surgery 6.3% (95% CI 2.5-10.1); genitourinary surgery 4.84% (95% CI 3.5-6.15); gastrointestinal surgery 5.2% (95% CI 3.9-6.4); gastroendoscopy 5.5% (95% CI 4.4-6.7); general surgery 6.3% (95% CI 5.5-7.1); ear, nose, and throat surgery 1.6% (95% CI 0-3.27); and cardiac electrophysiology (including pacemaker procedures) 6.6% (95% CI 1.1-12.4).

CONCLUSIONS

The SLUScore was independently, but variably, associated with 30-day mortality after noncardiac surgery.

Intraoperative Blood Pressure and Carbon Dioxide Values during Aneurysmal Repair and the Outcomes after Aneurysmal Subarachnoid Hemorrhage

Cerebral autoregulation impairment is a critical aspect of subarachnoid hemorrhage (SAH)-induced secondary brain injury and is also shown to be an independent predictor of delayed cerebral ischemia (DCI) and poor neurologic outcomes. Interestingly, intraoperative hemodynamic and ventilatory parameters were shown to influence patient outcomes after SAH. The aim of the current study was to evaluate the association of intraoperative hypotension and hypocapnia with the occurrence of angiographic vasospasm, DCI, and neurologic outcomes at discharge. Intraoperative data were collected for 390 patients with aneurysmal SAH who underwent general anesthesia for aneurysm clipping or coiling between January 2010 and May 2018. We measured the mean intraoperative blood pressure and end-tidal carbon dioxide (ETCO2), as well as the area under the curve (AUC) for the burden of hypotension: SBP below 100 or MBP below 65 and hypocapnia (ETCO2 < 30), during the intraoperative period. The outcome measures were angiographic vasospasm, DCI, and the neurologic outcomes at discharge as measured by the modified Rankin scale score (an mRS of 0-2 is a good outcome, and 3-6 is a poor outcome). Univariate and logistic regression analyses were performed to evaluate whether blood pressure (BP) and ETCO2 variables were independently associated with outcome measures. Out of 390 patients, 132 (34%) developed moderate-to-severe vasospasm, 114 (29%) developed DCI, and 46% (169) had good neurologic outcomes at discharge. None of the measured intraoperative BP and ETCO2 variables were associated with angiographic vasospasm, DCI, or poor neurologic outcomes. Our study did not identify an independent association between the degree of intraoperative hypotension or hypocapnia in relation to angiographic vasospasm, DCI, or the neurologic outcomes at discharge in SAH patients.

Intraoperative Beat-to-Beat Pulse Transit Time (PTT) Monitoring via Non-Invasive Piezoelectric/Piezocapacitive Peripheral Sensors Can Predict Changes in Invasively Acquired Blood Pressure in High-Risk Surgical Patients

BACKGROUND

Non-invasive tracking of beat-to-beat pulse transit time (PTT) via piezoelectric/piezocapacitive sensors (PES/PCS) may expand perioperative hemodynamic monitoring. This study evaluated the ability for PTT via PES/PCS to correlate with systolic, diastolic, and mean invasive blood pressure (SBP_IBP, DBP_IBP, and MAP_IBP, respectively) and to detect SBP_IBP fluctuations.

METHODS

PES/PCS and IBP measurements were performed in 20 patients undergoing abdominal, urological, and cardiac surgery. A Pearson's correlation analysis (r) between 1/PTT and IBP was performed. The predictive ability of 1/PTT with changes in SBP_IBP was determined by area under the curve (reported as AUC, sensitivity, specificity).

RESULTS

Significant correlations between 1/PTT and SBP_IBP were found for PES (r = 0.64) and PCS (r = 0.55) (p < 0.01), as well as MAP_IBP/DBP_IBP for PES (r = 0.6/0.55) and PCS (r = 0.5/0.45) (p < 0.05). A 7% decrease in 1/PTT_PES predicted a 30% SBP_IBP decrease (0.82, 0.76, 0.76), while a 5.6% increase predicted a 30% SBP_IBP increase (0.75, 0.7, 0.68). A 6.6% decrease in 1/PTT_PCS detected a 30% SBP_IBP decrease (0.81, 0.72, 0.8), while a 4.8% 1/PTT_PCS increase detected a 30% SBP_IBP increase (0.73, 0.64, 0.68).

CONCLUSIONS

Non-invasive beat-to-beat PTT via PES/PCS demonstrated significant correlations with IBP and detected significant changes in SBP_IBP. Thus, PES/PCS as a novel sensor technology may augment intraoperative hemodynamic monitoring during major surgery.

Blood pressure measurements during intraoperative pediatric scoliosis surgery

Background:

Intraoperative hypotension is frequently encountered during surgery and it can be associated with adverse outcomes. Blood pressure monitoring is critical during surgery, but there are no universally agreed upon standards for interpreting values of hypotension and no consensus regarding interventions.

Material and Methods:

We performed a retrospective chart review of pediatric patients who underwent idiopathic scoliosis surgery by a single surgeon. We used the arterial line for all measures. Intraoperative hypotension was defined as 20% decrease of the baseline systolic blood pressure (SBP), 30% decrease of baseline SBP, or mean arterial pressure less than 60 mmHg. Use of vasopressor agents was also recorded and correlated with blood pressure definitions.

Results:

Seventy idiopathic scoliosis patients were retrospectively evaluated. There was a significant correlation between the three measures of hypotension. Sixty percent of the patients received vasopressors. There was a significant correlation between a drop of mean arterial pressure to less than 60 mmHg and the use of the ephedrine. We did not find any changes on neuromonitoring measures during the case and there were no intraoperative or one-month postoperative complications.

Conclusions:

Blood pressure is only one of the measures anesthesiologists look to for good perfusion during surgery. Pediatric anesthesiologists and orthopedics agree in trying tight blood pressure control during surgery to decrease blood loss, but what the exact definition of that blood pressure number is, is still unclear. We propose that using mean arterial pressure less than 60 mmHg is perhaps a better definition. We provide recommendations for future studies.

The Role of Permissive and Induced Hypotension in Current Neuroanesthesia Practice

Background

Induced hypotension (IH) had been used for decades in neurosurgery to reduce the risk for intraoperative blood loss and decrease blood replacement. More recently, this method fell out of favor because of concerns for cerebral and other end-organ ischemia and worse treatment outcomes. Other contributing factors to the decline in its popularity include improvements in microsurgical technique, widespread use of endovascular procedures, and advances in blood conservation and transfusion protocols. Permissive hypotension (PH) is still being used occasionally in neurosurgery; however, its role in current anesthesia practice remains unclear. Our objective was to describe contemporary utilization of IH and PH (collectively called PH) in clinical practice among members of the Society for Neuroscience in Anesthesiology and Critical Care (SNACC).

Methods

A questionnaire was developed and distributed among SNACC members that addressed practice patterns related to the use of PH. The responses were analyzed based on the number of individuals who responded to each specific question.

Results

Of 72 respondents, 67.6% reported over 10 years of clinical experience, while 15.5% reported 5–10 years of post-training experience. The respondents admitted to providing anesthesia for 300 (median) neurosurgical cases per year. PH was applied most commonly during open interventions on cerebral aneurysms (50.8%) and arteriovenous malformations (46%). Seventy-three percent of respondents were not aware of any complications in their practice attributable to PH.

Conclusion

PH is still being used in neuroanesthesia practice by some providers. Further research is justified to clarify the risks and benefits of PH in modern neuroanesthesia practice.