Comparison Between Phenylephrine and Dopamine in Maintaining Cerebral Oxygen Saturation in Thoracic Surgery: A Randomized Controlled Trial

Comparison of peripheral blood saturation with brain oxygenation in patients undergoing thoracic surgery

Introduction

Near-infrared spectroscopy (NIRS) is a non-invasive method of regional tissue oxygenation measurement. Intraoperative use of NIRS to monitor brain oxygenation (BO) during surgery might be beneficial to identify cerebral desaturations.

Aim

To compare peripheral blood saturation (SpO2) with BO measurements and evaluate the utility of BO in thoracic surgery.

Material and methods

We took BO and SpO2 measurements in a group of 100 patients undergoing standard thoracic surgery. Measurements were made every 15 minutes. The Mann-Whitney U test was used to compare study groups. Spearman's rank correlation coefficient was used to determine correlation between studied parameters.

Results

We found a negative correlation between patients' age and BO at the beginning of surgery. Operations lasted between 30 and 200 minutes. We found a positive correlation between BO and SpO2 between 15 and 90 minutes of surgery. Subsequently, BO remained at a low level while SpO2 returned to baseline values. Higher minimum SpO2 values were noted in patients undergoing left-sided procedures.

Conclusions

Cerebral oxygenation does not return to baseline values until the end of the surgery as opposed to the SpO2. Furthermore, both SpO2 and BO correlate negatively with the overall duration of thoracic surgery. In addition, after 90 minutes of surgery, SpO2 stopped reflecting brain oxygenation.

Near-Infrared Spectroscopy (NIRS) for Cerebral and Tissue Oximetry: Analysis of Evolving Applications

THE USE OF NEAR-INFRARED SPECTROSCOPY (NIRS) has increased significantly worldwide in the past decade. This technology, first described more than 40 years ago, is based on the fact that near-infrared light is able to penetrate biologic tissue and can obtain real-time, noninvasive information on tissue oxygenation and metabolism. In the clinical setting, NIRS has been able to provide clinicians potentially valuable information in patients with impaired microcirculations (systemic and cerebral). Near-infrared spectroscopy has progressed beyond assessment of brain oxygenation to monitor local tissue and muscle oxygenation and perfusion. This review analyzes the published data and provides the clinician a comprehensive account of the perioperative utility of NIRS in cardiac, vascular and thoracic surgery, as well as its increasing role in tissue/muscle oxygenation monitoring.

The Regional Cerebral Oxygen Saturation Effect of Inotropes/Vasopressors Administered to Treat Intraoperative Hypotension: A Bayesian Network Meta-analysis

One of the main concerns of intraoperative hypotension is adequacy of cerebral perfusion, as cerebral blood flow decreases passively when mean arterial pressure falls below the lower limit of cerebral autoregulation. Treatment of intraoperative hypotension includes administration of drugs, such as inotropes and vasopressors, which have different pharmacological effects on cerebral hemodynamics; there is no consensus on the preferred drug to use. We performed a network meta-analysis (NMA) to pool and analyze data comparing the effect on cerebral oxygen saturation (ScO 2 ) measured by cerebral oximetry of various inotropes/vasopressors used to treat intraoperative hypotension. We searched randomized control trials in Embase, Ovid Medline, Scopus, Cochrane Central Register of Controlled Trials, and Web of Science. We included studies that enrolled adult patients undergoing surgery under general/spinal anesthesia that compared at least 2 inotropes/vasopressors to treat hypotension. We reviewed 51 full-text manuscripts and included 9 randomized controlled trials in our study. The primary outcome was change in ScO 2 . Our results showed the likelihood that dopamine, ephedrine, and norepinephrine had the lowest probability of decreasing ScO 2 . The suggested rank order to maintain ScO 2 , from higher to lower, was dopamine <ephedrine <norepinephrine <phenylephrine. Drugs in the lower rank order, like phenylephrine, produce higher reductions in ScO 2 . Compared with dopamine, the mean difference (95% credible interval) of ScO 2 reduction was: ephedrine -3.19 (-15.74, 8.82), norepinephrine -4.44 (-18.23, 9.63) and phenylephrine -6.93 (-18.31, 4.47). The results of our NMA suggest that dopamine and ephedrine are more likely to preserve ScO 2 , followed by norepinephrine. Compared with the other inotropes/vasopressors, phenylephrine decreased ScO 2 . Because of the inherent imprecision of direct/indirect comparisons, the rank orders are possibilities, not absolute ranks. Therefore the results of this NMA should be interpreted with caution.

Comparison of two vasopressor protocols for preventing hypotension post-spinal anesthesia during cesarean section: a randomized controlled trial

Background:

Norepinephrine infusion decreases hypotension after spinal anesthesia during cesarean section. This study aimed to compare the efficacy of norepinephrine infusion and ephedrine bolus against post-spinal hypotension in parturients.

Methods:

In this double-blinded, randomized controlled clinical trial, parturients scheduled for elective cesarean section were randomly allocated to receive norepinephrine infusion (0.05 μg·kg⁻¹·min⁻¹) just before spinal anesthesia continuing for 30 min or ephedrine bolus (0.15 mg/kg) just before spinal anesthesia. A rescue bolus (5 μg norepinephrine for the norepinephrine group, and 5 mg ephedrine for the ephedrine group) was administered whenever hypotension occurred. Our primary outcome was the incidence of hypotension within 30 min of spinal anesthesia administration. Secondary outcomes included maternal and neonatal outcomes 30 min after spinal block, and neonatal cerebral oxygenation 10 min after birth.

Results:

In total, 190 patients were enrolled; of these patients, 177 were included in the final analysis. Fewer patients suffered hypotension in the norepinephrine group than in the ephedrine group (29.5% vs. 44.9%, odds ratio [OR]: 0.51, 95% confidence interval [CI]: 0.28–0.95, P = 0.034). Moreover, the tachycardia frequency was lower in the norepinephrine group than in the ephedrine group (OR: 0.22, 95% CI: 0.11–0.44, P < 0.001), and patients suffered less nausea and vomiting (OR: 0.28, 95% CI: 0.11–0.70, P = 0.004). There was no difference in Apgar scores and umbilical arterial blood gas analysis between the two groups. However, neonatal cerebral regional saturations were significantly higher after birth in the norepinephrine group than in the ephedrine group (mean difference: 2.0%, 95% CI: 0.55%–3.45%, P = 0.008).

Conclusion:

In patients undergoing elective cesarean section with spinal anesthesia, norepinephrine infusion compared to ephedrine bolus resulted in less hypotension and tachycardia, and exhibited potential neonatal benefits.

Trial Registration:

ClinicalTrials.gov, NCT02542748; https://clinicaltrials.gov/ct2/show/record/NCT02542748

THE IMPORTANCE OF NON-INVASIVE REGIONAL BRAIN OXIMETRY IN PREVENTING POSTOPERATIVE COGNITIVE DYSFUNCTION DURING LAPAROSCOPIC CHOLECYSTECTOMY IN ELDERLY AND SENILE PATIENTS

The adverse effect of general anesthesia in elderly patients during surgery requires monitoring of functions and processes to identify their dangerous abnormalities to prevent complications. The aim of the study. To establish the effectiveness of non-invasive regional brain oximetry with rSO2 determination during anesthetic support in laparoscopic cholecystectomy (LCE) to prevent postoperative cognitive dysfunction in elderly and senile patients. Material and methods. 84 elderly and senile patients with diagnosed gallstone disease, acute cholecystitis, who underwent LCE with sevofluran inhalational anesthesia and total intravenous anesthesia with propofol were examined. rSO2 was monitored. Cognitive functions were assessed using neuropsychological scales and the MMSE mental state examination scale. Results. rSO2 was found to be significantly decreased during the carbon dioxide insufflation as compared to before premedication: in LH (left hemisphere) – by 7.0 %, in RH (right hemisphere) – by 6.9 % (Group I); in LH – by 7.4 %, in RH – by 7.5 % (Group II). rSO2 was significantly increased during the surgery, particularly in the middle of the operation, as compared to before premedication: in LH – by 14.66 %, in RH – by 13.94 % (Group I); in LH – by 11.60 %, in RH – by 11.53 % (Group II). The day following the surgery, cognitive functions significantly decreased by 8.7 % on the Luria's test, by 6.0 % on the MMSE test (Group I); in Group II – by 10.1 % and 6.3 %, respectively, as compared to before premedication. On Day 5 after the surgery, cognitive functions decreased by 2.7 % on the Luria's test, by 0.35 % on the MMSE test (Group I); in Group II – by 2.7 % and 0.35 %, respectively, as compared to before premedication. Conclusions. A decrease in rSO2 can occur during LCE in the Trendelenburg position, despite the fact that other intraoperative indicators remain stable, which allows it to remain unrecognized. rSO2 monitoring in the perioperative period contributes to alertness and timely measures to prevent postoperative cognitive dysfunction.

The effect of phenylephrine on cerebral perfusion when used to treat anesthesia-induced hypotension: a systematic review protocol

REVIEW QUESTION

The question of this review is: What is the effect of intravenous phenylephrine on cerebral perfusion in adult patients when administered to treat anesthesia-induced hypotension?

Comparison of Initial Vasopressors Used for Delayed Cerebral Ischemia after Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

The main reason for morbidity after aneurysmal subarachnoid hemorrhage (aSAH) is delayed cerebral ischemia (DCI). The mainstay of medical therapy for treating DCI is induced hypertension with vasopressors to restore cerebral perfusion. Both phenylephrine (PE) and norepinephrine (NE) are commonly used for induced hypertension, but the impact of the initial choice of vasopressor on the efficacy, adverse effects, or outcome after hemodynamic therapy for DCI is unknown.

METHODS

Sixty-three patients with aSAH between January 2012 and October 2014, who developed DCI (defined as new focal deficit or decline in Glasgow Coma Score) and in which PE (n = 45) or NE (n = 18) treatment was initiated were evaluated in this retrospective study. Baseline characteristics, adverse effects, the need to change or add vasopressors, the response to therapy, the need for endovascular therapy, new infarct development, discharge disposition, and 3 months modified Rankin score were all compared between pressor groups.

RESULTS

Baseline characteristics (e.g., Hunt Hess and Fisher grades) were similar. There were no differences in the overall rate of complications including arrhythmia, pulmonary edema, or kidney injury. However, those initiated on PE were more likely to be changed to an alternate vasopressor (64 vs. 33%, p = 0.016), mostly for bradycardia or failure to reach therapeutic targets. Patients initially treated with PE were less likely to respond neurologically (71 vs. 94%, p = 0.01) or to be discharged to home or acute rehabilitation facilities (73 vs. 94%, p = 0.02) and were more likely to have a delayed infarct on imaging (62 vs. 33%, p = 0.04).

CONCLUSIONS

Our study suggests that patients with DCI after aSAH initiated on PE are more likely to require treatment change to another vasopressor and are at greater risk for poor clinical outcomes compared to patients started on NE. Larger comparative studies are warranted.

Erratum: Comparison Between Phenylephrine and Dopamine in Maintaining Cerebral Oxygen Saturation in Thoracic Surgery: A Randomized Controlled Trial: Erratum

[This corrects the article DOI: 10.1097/MD.0000000000002212.].