Awareness, dreaming and unconscious memory formation during anaesthesia in children

Differences in the amplitude of low-frequency fluctuations of spontaneous brain activity between preterm and term infants

Objectives

To date, the majority of research on resting-state functional magnetic resonance imaging (rs-fMRI) in the developing brain has primarily centered on adolescents and adults, leaving a gap in understanding variations in spontaneous brain activity at rest in preterm infants. This study aimed to uncover and comprehend the distinctions in spontaneous brain activity between preterm and term infants, with the goal of establishing a foundation for assessing the condition of preterm infants.

Methods

In this study, 14 term infants and 15 preterm infants with equivalent gestational age were carefully chosen from the neonatal unit of Anhui Provincial Children's Hospital. The amplitude of low-frequency fluctuations (ALFF) intensity was assessed using resting-state functional magnetic resonance imaging (rs-fMRI) to examine brain activity in both groups. Subsequently, the differences between the term and preterm infants were statistically analyzed using a two-sample t-test. A p-value of <0.05, corrected for the REST Gaussian Random Fields, was deemed to be statistically significant.

Results

In comparison to the term infant group, the preterm infant group exhibited a significant increase in the ALFF value in the left precuneus, left frontal superior orbital gyrus, and left calcarine cortex.

Conclusion

Significant variances in spontaneous brain activity have been observed in various regions between term infants and preterm infants of equivalent gestational age. These variations could potentially impact the emotional and cognitive development of preterm infants in the long term.

The Impact of Scripted Self-Hypnotic Relaxation on the Periprocedural Experience and Anesthesiologist Sedation Use in the Pediatric Cardiac Catheterization Suite: A Prospective Randomized Controlled Trial

Purpose

To assess the impact on children of self-hypnotic relaxation scripts read by trained staff prior to the induction of anesthesia and/or extubation on the periprocedural experience.

Patients and Methods

A total of 160 children aged 7–18 years undergoing a cardiac catheterization intervention under general anesthesia were randomized into 4 groups: (1) a pre-procedure (PP-script) read prior to entering the procedural room, (2) a script read prior to extubation (PX-Script), (3) both PP- and PX-Scripts read and (4) no script read. Anxiety and pain were rated on self-reported 0–10 scales. The modified Yale Preoperative Anxiety Scale was used for preoperative anxiety. The effect of script reading was associated with outcomes by linear regression for continuous variables, and logistic regression for binary variables in two-sided tests at a significance level of 0.05. Results are given in odds ratios (OR) and 95% confidence intervals (CI).

Results

Data were available for 158 patients. Reading the PP-Script prior to anesthesia was associated with a significant reduction in the use of intraoperative sedatives from 30% to 14% (OR 0.40; CI 0.18–0.88; p = 0.02) by the anesthesiologists, who were blinded to group attribution until extubation. This was despite the children not self-reporting significantly lower levels of anxiety or pain. The PX-Script did not change outcomes. Among groups, there was no significant difference in room time, postoperative recovery time and pain.

Conclusion

Reading a PP-Script for guidance in self-hypnotic relaxation can result in less need for intravenous sedation in the judgment of the anesthesiologist, independent of the children’s self-reported anxiety and pain. This raises interesting questions about subconscious patient–physician interactions affecting pain management.

Clinicaltrials.gov Identifier

NCT02347748.

Use of dexmedetomidine and opioids as the primary anesthetic in infants and young children: A retrospective cohort study

BACKGROUND

Anesthetic regimens using dexmedetomidine and short-acting opioids have been suggested as potential alternatives to sevoflurane-based anesthesia in children. The primary aim of this study is to compare demographics, intraoperative characteristics, and complications of general anesthetics in which dexmedetomidine and opioids were used without sevoflurane, or in combination with a low sevoflurane concentration, in children 36 months old and younger. The secondary aim is to evaluate intraoperative bispectral index (BIS) values when available in these patients.

METHODS

General anesthetics performed between January 1, 2017, and May 1, 2018, in children 2 years and younger who received dexmedetomidine and remifentanil, with or without sevoflurane, were identified. Additional anesthetics performed during this time in children 36 months and younger who received dexmedetomidine and opioids and had BIS monitoring were also identified. Charts were reviewed for demographic and intraoperative variables, including drug administration and hemodynamic data.

RESULTS

A total of 244 patients were identified. All but 22 patients received remifentanil. Ninety-two patients received sevoflurane with a mean end-tidal concentration of 0.84% (SD 0.43). Compared to the sevoflurane group, the nonsevoflurane group received more remifentanil (median dose 0.4 μg/kg/min vs 0.2 μg/kg/min, difference of 0.1 μg/kg/min, 95% CI 0.1-0.3, P < .001) and more dexmedetomidine (median dose 0.9 μg/kg/h vs 0.3 μg/kg/h, difference of 0.6 μg/kg/h, 95% CI 0.4-0.8, P < .001), and had a higher mean arterial pressure (median 53 mm Hg vs 42 mm Hg, difference of 11 mm Hg, 95% CI 8.1-14.8, P < .001). Complications between the two groups were comparable. The median percent intraoperative time with BIS reading <60 was 71.6% (95% CI: 63.3%-79.8%).

CONCLUSION

Dexmedetomidine and opioids can effectively be used in young children as an alternative total intravenous anesthesia technique with or without <1 minimum alveolar concentration of sevoflurane. Bispectral index monitoring reveals a likely sufficient depth of hypnosis.

Helping Children Cope with Medical Tests and Interventions

Medical procedures and tests become a challenge when anxiety and pain make it difficult for the patient to cooperate or remain still when needed. Fortunately a short intervention with hypnoidal language at the onset of a procedure induces a positive and sustained change in the way pain and anxiety are processed. While anesthesia may appear to be a simple solution to eliminate pain, the adverse effects of pre-anesthesia anxiety on postoperative behavior and recovery are often not fully appreciated. This paper discusses options for self-hypnotic relaxation that are applicable to interactions with children. The high suggestibility of children makes it relatively easy to engage them in make-believe scenarios. Avoidance of negative suggestions is key in avoiding nocebo effects that may be difficult to overcome later. Once a child is immersed in his or her preferred scenario or hobby/activity of choice, environmental and procedural stimuli can be easily integrated in the imagery. Ego-strengthening metaphors that tie in features of strength, confidence, or resilience are particularly empowering. Even when children are fully under general anesthesia they may still have recall of what is said in the room and therefore caution in word choice should be maintained.

A pilot study to determine whether visually evoked hemodynamic responses are preserved in children during inhalational anesthesia

BACKGROUND

Anesthetic depth is an important parameter to monitor during surgery, yet remains difficult to quantify, particularly in young children where developmental changes influence the electroencephalogram. A more fundamental physiological response to stimulation is the increase in cerebral blood flow secondary to increased metabolic demand, referred to as flow-metabolism coupling (FMC) and measurable using near-infrared spectroscopy (NIRS). Little is known about the effect of anesthesia on FMC; therefore, we studied visually evoked hemodynamic responses (VEHRs) using NIRS in children undergoing general anesthesia for minor surgical procedures.

METHOD

We recruited 23 children (aged 2-5 years), undergoing surgery requiring general anesthesia. VEHRs were measured for 30 min using NIRS, including 5 min of baseline recording after anesthetic induction. Parameters recorded using NIRS included the concentrations of oxygenated (oxy), deoxygenated (deoxy), and total hemoglobin (Hb), which were separated into epochs for evoked response analysis after filtration of motion artifact and baseline drift. Goodness-of-fit statistics and classification rules were used to determine the existence of evoked responses, and a modified Gaussian equation was used to model each evoked response.

RESULTS

Near-infrared spectroscopy data were recorded in 20/23 children, of whom nine showed a VEHR. No responses were seen in the baseline control data. When examining the relationship between VEHR and anesthetic agents, we noted that for 8/10 patients in whom preoperative or intraoperative fentanyl were administered and VEHRs were absent.

CONCLUSION

We have shown that VEHRs can be detected using NIRS in some anesthetized children. Administration of fentanyl was associated with an absence of VEHRs. The mechanism underlying this association is unclear.

Anesthesia awareness: narrative review of psychological sequelae, treatment, and incidence

Awareness during general anesthesia occurs when patients recall events or sensations during their surgeries, although the patients should have been unconscious at the time. Anesthesiologists are cognizant of this phenomenon, but few discussions occur outside the discipline. This narrative review summarizes the patient recollections, psychological sequelae, treatment and follow-up of psychological consequences, as well as incidence and etiology of awareness during general anesthesia. Recalled memories include noises, conversations, images, mental processes, feelings of pain and/or paralysis. Psychological consequences include anxiety, flashbacks, and posttraumatic stress disorder diagnosis. Limited discussion for therapeutic treatment after an anesthesia awareness experience exists. The incidence of anesthesia awareness ranges from 0.1 to 0.2% (e.g., 1-2/1000 patients). Increased recognition of awareness during general anesthesia within the psychological/counseling community, with additional research focusing on optimal therapeutic treatment, will improve the care of these patients.

Effects of therapeutic suggestion in children undergoing general anesthesia: a randomized controlled trial

OBJECTIVES AND AIM

The goal of this randomized controlled trial was to examine the effect of intraoperative positive therapeutic suggestion on postoperative nausea and vomiting (PONV) in children undergoing general anesthesia and otolaryngological surgery.

BACKGROUND

Because of the high incidence of PONV following otolaryngological surgery and its negative impact on recovery, researchers have examined various nonpharmacological interventions to target this phenomenon. To date, the effectiveness of therapeutic suggestion has not been studied in children.

METHODS

Participants were 67 children undergoing tonsillectomy and adenoidectomy and their mothers. Children received a standardized anesthetic procedure and were randomly assigned to one of three interventions administered under general anesthesia: therapeutic suggestion, story (prosody control), or standard operating room noise. Children, parents, and healthcare personnel were blinded to group assignment. Nausea and vomiting were recorded in the postanesthesia care unit (PACU) and for the first 3 days at home.

RESULTS

Results demonstrated a decrease in nausea severity across the first 3 days, F(2,49) = 10.37, P < 0.001, but no group differences in nausea severity in the PACU (F(2,49) = 0.87, P = 0.43) or at home (F(2,49) = 0.80, P = 0.46). There were also no group differences in vomiting episodes in the PACU (chi(2) (2) = 1.25, P > 0.05) or at home (F(2,49) = 1.59, P = 0.21).

CONCLUSIONS

In this blinded controlled trial, therapeutic suggestion delivered intraoperatively did not impact children's PONV. However, because this is the first study of this kind, replication may be needed.

Evidence on the emergence of the brain's default network from 2-week-old to 2-year-old healthy pediatric subjects

Several lines of evidence have implicated the existence of the brain's default network during passive or undirected mental states. Nevertheless, results on the emergence of the default network in very young pediatric subjects are lacking. Using resting functional magnetic resonance imaging in healthy pediatric subjects between 2 weeks and 2 years of age, we describe the temporal evolution of the default network in a critical, previously unstudied, period of early human brain development. Our results demonstrate that a primitive and incomplete default network is present in 2-week-olds, followed by a marked increase in the number of brain regions exhibiting connectivity, and the percent of connection at 1 year of age. By 2 years of age, the default network becomes similar to that observed in adults, including medial prefrontal cortex (MPFC), posterior cingulate cortex/retrosplenial (PCC/Rsp), inferior parietal lobule, lateral temporal cortex, and hippocampus regions. While the anatomical representations of the default network highly depend on age, the PCC/Rsp is consistently observed at in both age groups and is central to the most and strongest connections of the default network, suggesting that PCC/Rsp may serve as the main "hub" of the default network as this region does in adults. In addition, although not as remarkable as the PCC/Rsp, the MPFC also emerges as a potential secondary hub starting from 1 year of age. These findings reveal the temporal development of the default network in the critical period of early brain development and offer new insights into the emergence of brain default network.

Balancing paediatric anaesthesia: preclinical insights into analgesia, hypnosis, neuroprotection, and neurotoxicity

Logistical and ethical reasons make conducting clinical research in paediatric practice difficult, and therefore safe and efficacious advances are dependent on good preclinical research. For example, notable advances have been made in preclinical studies of pain processing that correlate well with patient data. Other areas of paediatric anaesthetic research remain in their infancy including mechanisms of anaesthesia and anaesthetic neuroprotection and neurotoxicity. Animal data have identified the potential 'double-edged' sword of administering anaesthetic agents in the young; although these agents can be neuroprotective in certain circumstances, they can be neurotoxic in others. The potential for this toxicity must be balanced against the importance of providing adequate anaesthesia for which there can be no compromise. We review the current state of preclinical research in paediatric anaesthesia and identify areas which require further exploration in order to provide the foundations for well-conducted clinical trials.

Awareness in children: another two cases

Intraoperative awareness is an anesthesia complication and occurs when a patient becomes conscious during a procedure performed under general anesthesia and subsequently has recall of these events. Awareness is well described phenomenon in adults, with an incidence of 0.1-0.2 % for low-risk surgical procedures. Recent studies have shown that awareness in children is more common than in adults. However, causes and the long-term psychological impact of awareness in children are unknown. We report on two cases of intraoperative awareness in children in an attempt to throw further light on this complex problem.