Sustaining Life versus Altering Life-Saving Drugs: Insights to Explain the Paradoxical Effect of Extracorporeal Membrane Oxygenation on Drugs

There has been a substantial increase in the use of extracorporeal membrane oxygenation (ECMO) support in critically ill adults. Understanding the complex changes that could affect drugs' pharmacokinetics (PK) and pharmacodynamics (PD) is of suitable need. Therefore, critically ill patients on ECMO represent a challenging clinical situation to manage pharmacotherapy. Thus, clinicians' ability to predict PK and PD alterations within this complex clinical context is fundamental to ensure further optimal and, sometimes, individualized therapeutic plans that balance clinical outcomes with the minimum drug adverse events. Although ECMO remains an irreplaceable extracorporeal technology, and despite the resurgence in its use for respiratory and cardiac failures, especially in the era of the COVID-19 pandemic, scarce data exist on both its effect on the most commonly used drugs and their relative management to achieve the best therapeutic outcomes. The goal of this review is to provide key information about some evidence-based PK alterations of the drugs used in an ECMO setting and their monitoring.

Association of sedation and anesthesia on cognitive outcomes in very premature infants: a retrospective observational study

PURPOSE

Cognitive outcomes in preterm infants may be adversely affected by use of sedation and anesthetic agents. We investigated the associations between anesthetics/sedatives and full-scale intelligence quotient (FSIQ) measured at 36 months corrected age (CA) in very preterm infants (born < 29 weeks gestational age).

METHODS

This retrospective cohort study included preterm infants born at < 29 weeks of gestation between 1 January 2006 and 31 December 2012, whose cognitive outcomes were assessed at 36 months CA. Imputed and complete case univariable and adjusted multivariable linear regressions were used to investigate the associations between FSIQ [standardized to mean (standard deviation) 100 (15)] and exposure to volatile anesthetics, propofol, benzodiazepines, barbiturates, and ketamine. These agents were the subject of a 2016 warning from regulatory authorities in the USA recommending caution for administration to children and pregnant women.

RESULTS

A total of 731 infants met the inclusion criteria. Unadjusted associations were -7 (95% confidence interval [CI], -10 to -4; P < 0.001) and -6 (95% CI, -10 to -3; P < 0.001) FSIQ points with exposure to warned medications using imputed and complete case analyses, respectively. Imputed and complete case adjusted associations between FSIQ and warned medications were -3 (95% CI, -7 to 0; P = 0.045) and -4 (95% CI, -8 to 0; P = 0.071) FSIQ points, respectively. Adjusted associations between volatile anesthetic exposure only and FSIQ were -3 (95% CI, -6 to 0; P = 0.072) and -5 (95% CI, -9 to -2; P = 0.004) FSIQ points using imputed and complete case data sets, respectively. FSIQ was not associated with opioid exposure.

CONCLUSION

Exposure of very preterm infants to anesthetics/sedatives on the United States Food and Drug Administration warning list was associated with a decrease in FSIQ points at 36 months CA. There was no association between opioid exposure and FSIQ.

The Impact of Vasopressor and Sedative Agents on Cerebrovascular Reactivity and Compensatory Reserve in Traumatic Brain Injury: An Exploratory Analysis

The impact of vasopressor and sedative drugs on cerebrovascular reactivity in traumatic brain injury (TBI) remains unclear. The aim of this study was to evaluate the impact of changes of doses of commonly administered sedation (i.e., propofol, fentanyl, and ketamine) and vasopressor agents (i.e., norepinephrine [NE], phenylephrine [PE], and vasopressin[VSP]) on cerebrovascular reactivity and compensatory reserve in patients with moderate/severe TBI. Using the Winnipeg Acute TBI Database, we identified 38 patients with more than 1000 distinct changes of infusion rates and more than 500 h of paired drug infusion/physiology data. Cerebrovascular reactivity was assessed using pressure reactivity index (PRx) and cerebral compensatory reserve was assessed using RAP (the correlation [R] between pulse amplitude of intracranial pressure [ICP; A] and ICP [P]). We evaluated the data in two phases. First, we assessed the relationship between mean hourly dose of medication and its relation to both mean hourly index values, and time spent above a given index threshold. Second, we evaluated time-series data for each individual dose change per medication, assessing for a statistically significant change in PRx and RAP metrics. The results of the analysis confirmed that, overall, the mean hourly dose of sedative (propofol, fentanyl, and ketamine) and vasopressor (NE, PE, and VSP) agents does not impact hourly cerebrovascular reactivity or compensatory reserve measures. Similarly, incremental dose changes in these medications in general do not lead to significant changes in cerebrovascular reactivity or compensatory reserve. For propofol with incremental dose increases, in situations where PRx is intact (i.e., PRx <0 prior), a statistically significant increase in PRx was seen. However, this may not indicate deteriorating cerebrovascular reactivity as the final PRx (∼0.05) may still be considered to be intact cerebrovascular reactivity. As such, this finding with regards to propofol remains “weak.” This study indicates that commonly administered sedative and vasopressor agents with incremental dosing changes have no clinically significant influence on cerebrovascular reactivity or compensatory reserve in TBI. These results should be considered preliminary, requiring further investigation.

Prospective audit of sedation/anesthesia practices for children undergoing computerized tomography in a tertiary care institute

Background and Aims:

The aim of the study was to enumerate the sedative drugs used, assess the efficacy of sedative drugs, and determine the incidence of adverse events.

Material and Methods:

A prospective audit of children sedated for computerized tomography (CT) by anesthesiology team was conducted for a period of 4 months. The data included patient demographic variables, fasting period, medications administered, adequacy of sedation, imaging characteristics, adverse events, and requirement for escalated care.

Results:

A total of 331 children were enrolled for sedation by the anesthesia team. The drugs used for sedation were propofol, ketamine, and midazolam. Twenty-two percent children received one sedative drug, 60% children were administered two drugs, and 5% children required a combination of all three drugs for successful sedation. Sedation was effective for successful conduct of CT scan in 95.8% patients without the requirement of a repeat scan. Twelve (5%) children experienced adverse events during the study period. However, none of the adverse events necessitated prolonged postprocedural hospitalization or resulted in permanent neurologic injury or death.

Conclusions:

The current practice of sedation with propofol, ketamine, and midazolam, either single or in combination was efficacious in a high percentage of patients. The incidence of adverse events during the study period was low.

Cortisol evaluation during the acute phase of traumatic brain injury-A prospective study

BACKGROUND

Biochemical diagnosis of adrenal insufficiency (AI) is difficult in the context of traumatic brain injury (TBI).

AIM

To assess the frequency and predictive factors of AI in victims of TBI from Algiers.

METHODS

Between November 2009 and December 2013, TBI victims had a single 8-9 am serum cortisol measurement during the acute postinjury period (0-7 days). AI was defined according to basal cortisol levels of 83, 276 and 414 nmol/L. Variables studied were TBI severity according to Glasgow coma scale, duration of intubation and coma, pupillary status, hypotension, anaemia, brain imaging findings, diabetes insipidus and medication. Insulin tolerance test was performed during the recovery phase, defining AI as peak cortisol <500 nmol/L.

RESULTS

Cortisol samples were obtained at median 3 (1-7) days from 277 patients (257M: 20F) aged 32 (18-65) years. Acute AI frequency was 8 (2.8%), 20 (21%) and 35 (37%), respectively using the three cortisol cut-offs. Factors predicting AI were diastolic hypotension, sedative medication, diabetes insipidus, skull base fracture and intraparenchymal haematoma. Mortality was highest in patients with acute cortisol <276 nmol/L (44.6% with OR for death 1.64, 95% CI 0.92-3.0, P = .12). During the recovery phase, AI was present in 3 of 3, 12 of 24, 4 of 16 and 20 of 66 patients with week 1 cortisol <83, 83-276, 277-414 and >414 nmol/L.

CONCLUSION

Hydrocortisone replacement is advised in TBI patients with morning cortisol <276 nmol/L or those <414 nmol/L with additional risk factors for AI. As acute and subsequent AI are poorly correlated, patients with moderate/severe TBI require adrenal re-evaluation during the recovery phase.