The timing and prevalence of intraoperative hypotension in infants undergoing laparoscopic pyloromyotomy at a tertiary pediatric hospital

After nectarine: how should we provide anesthesia for neonates?

PURPOSE OF REVIEW

Neonates have a high risk of perioperative morbidity and mortality. The NEonate and Children audiT of Anaesthesia pRactice IN Europe (NECTARINE) investigated the anesthesia practice, complications and perioperative morbidity and mortality in neonates and infants <60 weeks post menstrual age requiring anesthesia across 165 European hospitals. The goal of this review is to highlight recent publications in the context of the NECTARINE findings and subsequent changes in clinical practice.

RECENT FINDINGS

A perioperative triad of hypoxia, anemia, and hypotension is associated with an increased overall mortality at 30 days. Hypoxia is frequent at induction and during maintenance of anesthesia and is commonly addressed once oxygen saturation fall below 85%.Blood transfusion practices vary widely variable among anesthesiologists and blood pressure is only a poor surrogate of tissue perfusion. Newer technologies, whereas acknowledging important limitations, may represent the currently best tools available to monitor tissue perfusion. Harmonization of pediatric anesthesia education and training, development of evidence-based practice guidelines, and provision of centralized care appear to be paramount as well as pediatric center referrals and international data collection networks.

SUMMARY

The NECTARINE provided new insights into European neonatal anesthesia practice and subsequent morbidity and mortality.Maintenance of physiological homeostasis, optimization of oxygen delivery by avoiding the triad of hypotension, hypoxia, and anemia are the main factors to reduce morbidity and mortality. Underlying and preexisting conditions such as prematurity, congenital abnormalities carry high risk of morbidity and mortality and require specialist care in pediatric referral centers.

Intraoperative Hypotension and Acute Kidney Injury after Noncardiac Surgery in Infants and Children: A Retrospective Cohort Analysis

BACKGROUND

Age- and sex-specific reference nomograms for intraoperative blood pressure have been published, but they do not identify harm thresholds. The authors therefore assessed the relationship between various absolute and relative characterizations of hypotension and acute kidney injury in children having noncardiac surgery.

METHODS

The authors conducted a retrospective cohort study using electronic data from two tertiary care centers. They included inpatients 18 yr or younger who had noncardiac surgery with general anesthesia. Postoperative renal injury was defined using the Kidney Disease Improving Global Outcomes definitions, based on serum creatinine concentrations. The authors evaluated potential renal harm thresholds for absolute lowest intraoperative mean arterial pressure (MAP) or largest MAP reduction from baseline maintained for a cumulative period of 5 min. Separate analyses were performed in children aged 2 yr or younger, 2 to 6 yr, 6 to 12 yr, and 12 to 18 yr.

RESULTS

Among 64,412 children who had noncardiac surgery, 4,506 had creatinine assessed preoperatively and postoperatively. The incidence of acute kidney injury in this population was 11% (499 of 4,506): 17% in children under 6 yr old, 11% in children 6 to 12 yr old, and 6% in adolescents, which is similar to the incidence reported in adults. There was no association between lowest cumulative MAP sustained for 5 min and postoperative kidney injury. Similarly, there was no association between largest cumulative percentage MAP reduction and postoperative kidney injury. The adjusted estimated odds for kidney injury was 0.99 (95% CI, 0.94 to 1.05) for each 5-mmHg decrease in lowest MAP and 1.00 (95% CI, 0.97 to 1.03) for each 5% decrease in largest MAP reduction from baseline.

CONCLUSIONS

In distinct contrast to adults, the authors did not find any association between intraoperative hypotension and postoperative renal injury. Avoiding short periods of hypotension should not be the clinician's primary concern when trying to prevent intraoperative renal injury in pediatric patients.

EDITOR’S PERSPECTIVE

Predicting hypotension during anesthesia: Variation in pulse oximetry plethysmography predicts propofol-induced hypotension in children

BACKGROUND

The development of hypotension on administration of intravenous propofol is common and independently associated with adverse outcomes. Identifying patients with a high risk for anesthesia-induced hypotension may help anesthesiologists prepare for such an event.

AIM

The authors hypothesized that propofol-induced hypotension is predictable by variables related to fluid responsiveness and investigated such variables to determine the factors which can predict hypotensive events.

METHODS

Patients 3-6 years of age who underwent general were included. Intravenous midazolam 0.1 mg kg^-1 was administered as premedication, and preoperative noninvasive blood pressure, heart rate, perfusion index, pleth variability index, and respiratory variation of pulse oximetry plethysmographic waveform were measured. Intravenous propofol 2.5 mg kg^-1 was given, and blood pressure was measured 5 times at 1-min intervals. Subjects with significant hypotension (mean blood pressure decrease ≥20%) were allocated to the hypotensive group; those without significant hypotension were allocated to the relatively normotensive group.

RESULTS

Of 77 patients, 50 (64.9%) developed significant hypotension. Patients in the hypotensive group exhibited significantly higher respiratory variation of pulse oximetry plethysmographic waveform (mean difference 11 [3.3] [95% confidence interval 4.9-18.1]; p = .001) and higher pleth variability index (mean difference 7.1 [2.8] [95% confidence interval 1.6-12.6]; p = .013) than the normotensive group. The areas under the receiver operating characteristic curve for respiratory variation of pulse oximetry plethysmographic waveform and pleth variability index were 0.722 and 0.649, respectively.

CONCLUSION

High preoperative respiratory variation of pulse oximetry plethysmographic waveform and pleth variability index were both independently associated with propofol-induced hypotension in children.

Preoperative Fluid Fasting Times and Postinduction Low Blood Pressure in Children

Background

Children are required to fast before elective general anesthesia. This study hypothesized that prolonged fasting causes volume depletion that manifests as low blood pressure. This study aimed to assess the association between fluid fasting duration and postinduction low blood pressure.

Methods

A retrospective cohort study was performed of 15,543 anesthetized children without preinduction venous access who underwent elective surgery from 2016 to 2017 at Children’s Hospital of Philadelphia. Low blood pressure was defined as systolic blood pressure lower than 2 standard deviations below the mean (approximately the 2.5th percentile) for sex- and age-specific reference values. Two epochs were assessed: epoch 1 was from induction to completion of anesthesia preparation, and epoch 2 was during surgical preparation.

Results

In epoch 1, the incidence of low systolic blood pressure was 5.2% (697 of 13,497), and no association was observed with the fluid fasting time groups: less than 4 h (4.6%, 141 of 3,081), 4 to 8 h (6.0%, 219 of 3,652), 8 to 12 h (4.9%, 124 of 2,526), and more than 12 h (5.0%, 213 of 4,238). In epoch 2, the incidence of low systolic blood pressure was 6.9% (889 of 12,917) and varied across the fasting groups: less than 4 h (5.6%, 162 of 2,918), 4 to 8 h (8.1%, 285 of 3,531), 8 to 12 h (5.9%, 143 of 2,423), and more than 12 h (7.4%, 299 of 4,045); after adjusting for confounders, fasting 4 to 8 h (adjusted odds ratio, 1.33; 95% CI, 1.07 to 1.64; P = 0.009) and greater than 12 h (adjusted odds ratio, 1.28; 95% CI, 1.04 to 1.57; P = 0.018) were associated with significantly higher odds of low systolic blood pressure compared with the group who fasted less than 4 h, whereas the increased odds of low systolic blood pressure associated with fasting 8 to 12 h (adjusted odds ratio, 1.11; 95% CI, 0.87 to 1.42; P = 0.391) was nonsignificant.

Conclusions

Longer durations of clear fluid fasting in anesthetized children were associated with increased risk of postinduction low blood pressure during surgical preparation, although this association appeared nonlinear.

Editor’s Perspective

What We Already Know about This Topic

What This Article Tells Us That Is New

Integrating intraoperative physiology data into outcome analysis for the ACS Pediatric National Surgical Quality Improvement Program

BACKGROUND

The Pediatric National Surgical Quality Improvement Program (P-NSQIP) samples surgical procedures for benchmarking and quality improvement. While generally comprehensive, P-NSQIP does not collect intraoperative physiologic data, despite potential impact on outcomes.

AIMS

The aims of this study were (a) to describe a methodology to augment P-NSQIP with vital signs data and (b) demonstrate its utility by exploring relationships that intraoperative hypothermia and hypotension have with P-NSQIP outcomes.

METHODS

Vital signs from 2012 to 2016 were available in a research databank. Episodes of hypotension and hypothermia were extracted and recorded alongside local P-NSQIP data. Multivariable regression analyses were performed to explore associations with undesired outcomes, including: surgical site infection, wound disruption, unplanned return to the operating room, and blood transfusion. Model variables were selected with the Akaike information criterion using 2012-2014 as the training set and validated with receiver operating characteristics analysis using 2015-2016 as the testing set.

RESULTS

Data from 6737 patients were analyzed, with 43.9% female, median [interquartile range] age 5.8 [1.3-12.4] years, undergoing procedures lasting 118 [75-193] minutes. Hypothermia, observed in 45% of cases, was associated with wound disruption (odds ratio 1.75, 95% CI 1.1-2.83). Hypotension, observed in 60% of cases, was associated with unplanned returns (odds ratio 1.58, 95% CI 1.02-2.51), and transfusions (odds ratio 1.95, 95% CI 1.14-3.52). Surgical site infection, wound disruption, unplanned return, and transfusion models had areas under the receiver operating characteristic curve of 0.69/0.67, 0.59/0.63, 0.78/0.79, and 0.92/0.93 for validation models including hypothermia/hypotension respectively.

CONCLUSION

Adding intraoperative vital signs to P-NSQIP data allowed identification of two modifiable risk factors: hypothermia was associated with increased wound disruption, and hypotension with increased blood transfusions and unplanned returns to the operating room. These findings may motivate prospective studies and prompt other centers and P-NSQIP to augment outcome data with intraoperative physiological data.