Ketamine PCA for treatment of end-of-life neuropathic pain in pediatrics

The Use of Ketamine for Malignant and Nonmalignant Chronic Pain in Children: A Review of Current Evidence

Chronic pain in children continues to pose significant challenges. The pharmacological approach most often revolves around trials and errors, expert opinions, and extrapolation of adult study findings. Ketamine is one of the agents used for chronic pain, especially with a neuropathic component. This article aims to provide an overview of its properties and highlight the current evidence for its use in malignant and nonmalignant chronic pain management. A search on the use of ketamine for chronic pain in children up to 18 years of age covering the period from January 1, 2000, to December 14, 2022, was performed through PubMed, Cochrane Library, EBSCO, EBM Review, Wiley, BMJ, Web of Science, Google Scholar, and the Saudi Digital Library. 218 articles were found and 42 underwent full review. Currently, the evidence about ketamine efficacity and safety for chronic pain management is at best of moderate to low quality. The heterogeinity of ketamine infusion protocols and frequent concomitant use of other analgesics make it difficult to draw robust conclusions. The long-term effect of prolonged usage also remains a concern. Nevertheless, with careful monitoring, the drug may be a reasonable choice for malignant and nonmalignant pain management in selected cases, especially for refractory pain not responding to conventional approaches.

The Pharmacological Treatment of Neuropathic Pain in Children

The International Association for the Study of Pain (IASP) defines neuropathic pain as pain caused by a lesion or disease of the somatosensory nervous system. It is characterized as a clinical condition in which diagnostic studies reveal an underlying cause of an abnormality in the peripheral or central nervous system. Many common causes of neuropathic pain in adults are rare in children. The purpose of this focused narrative review is, to 1) provide an overview of neuropathic pain in children, 2) highlight unique considerations related to the diagnosis and mechanisms of neuropathic pain in children, and 3) perform a comprehensive analysis of the pharmacological treatments available. We emphasize that data for routine use of pharmacological agents in children with neuropathic pain are largely inferred from adult literature with little research performed on pediatric populations, yet have clear evidence of harms to pediatric patients. Based on these findings, we propose risk mitigation strategies such as utilizing topical treatments whenever possible, assessing pain phenotyping to guide drug class choice, and considering pharmaceuticals in the broader context of the multidisciplinary treatment of pediatric pain. Furthermore, we highlight important directions for future research on pediatric neuropathic pain treatment.

Recommendations for analgesia and sedation in critically ill children admitted to intensive care unit

We aim to develop evidence-based recommendations for intensivists caring for children admitted to intensive care units and requiring analgesia and sedation. A panel of national paediatric intensivists expert in the field of analgesia and sedation and other specialists (a paediatrician, a neuropsychiatrist, a psychologist, a neurologist, a pharmacologist, an anaesthesiologist, two critical care nurses, a methodologist) started in 2018, a 2-year process. Three meetings and one electronic-based discussion were dedicated to the development of the recommendations (presentation of the project, selection of research questions, overview of text related to the research questions, discussion of recommendations). A telematic anonymous consultation was adopted to reach the final agreement on recommendations. A formal conflict-of-interest declaration was obtained from all the authors. Eight areas of direct interest and one additional topic were considered to identify the best available evidence and to develop the recommendations using the Evidence-to-Decision framework according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. For each recommendation, the level of evidence, the strength of the recommendation, the benefits, the harms and the risks, the benefit/harm balance, the intentional vagueness, the values judgement, the exclusions, the difference of the opinions, the knowledge gaps, and the research opportunities were reported. The panel produced 17 recommendations. Nine were evaluated as strong, 3 as moderate, and 5 as weak. Conclusion: a panel of national experts achieved consensus regarding recommendations for the best care in terms of analgesia and sedation in critically ill children.

Refractory symptoms in paediatric palliative care: can ketamine help?

BACKGROUND

One of the main challenges for paediatric palliative care (PPC) is the management of concomitant, different and severe symptoms that frequently affect the quality of life of PPC patients and are often refractory to commonly used pharmacological treatments. Consequently, many efforts are still needed to find the best therapeutic options to handle these refractory conditions. Since the first synthesis of ketamine in the 1960s, its pharmacokinetic and pharmacodynamic properties have been largely investigated and its potential wide range of clinical applications has become clear. However, this molecule still receives poor attention in some areas, including in children and PPC. This narrative review analyses the use of ketamine in children and the potential extension of its applications in PPC in order to provide new options for treatment in the PPC setting.

METHODS

Scientific papers published before October 2020 on MEDLINE, EMBASE and the Cochrane Library were considered. The cited references of the selected papers and the authors' personal collections of literature were reviewed. The terms "palliative care", "ketamine", "neuropathic pain", "procedural pain", "status epilepticus", "refractory pain" and "child", adding "age: birth-18 years" on a further filter were used for the search.

DISCUSSION

The use of ketamine in PPC should be more widely considered due to its overall favourable safety profile and its efficacy, which are supported by an increasing number of studies, although in settings different from PPC and of mixed quality. Ketamine should be proposed according to a case-by-case evaluation and the specific diagnosis and the dosage and route of administration should be tailored to the specific needs of patients. Furthermore, there is evidence to suggest that ketamine is safe and efficacious in acute pain. These findings can prompt further research on the use of ketamine for the treatment of acute pain in PPC.

CONCLUSION

Ketamine could be a suitable option after the failure of conventional drugs in the treatment of different refractory conditions in PPC.

Healthcare interventions improving and reducing quality of life in children at the end of life: a systematic review

BACKGROUND

Children with serious illness suffer from symptoms at the end of life that often fail to be relieved. An overview is required of healthcare interventions improving and decreasing quality of life (QOL) for children with serious illness at the end of life.

METHODS

A systematic review was performed in five databases, January 2000 to July 2018 without language limit. Reviewers selected quantitative studies with a healthcare intervention, for example, medication or treatment, and QOL outcomes or QOL-related measures, for example, symptoms, for children aged 1-17 years with serious illness. One author assessed outcomes with the QualSyst and GRADE (Grades of Recommendation, Assessment, Development, and Evaluation) Framework; two authors checked a 25% sample. QOL improvement or reduction was categorized.

RESULTS

Thirty-six studies met the eligibility criteria studying 20 unique interventions. Designs included 1 randomized controlled trial, 1 cross-sectional study, and 34 cohort studies. Patient-reported symptom monitoring increased QOL significantly in cancer patients in a randomized controlled trial. Dexmedetomidine, methadone, ventilation, pleurodesis, and palliative care were significantly associated with improved QOL, and chemotherapy, stem cell transplant, and hospitalization with reduced QOL, in cohort studies.

CONCLUSIONS

Use of patient-controlled symptom feedback, multidisciplinary palliative care teams with full-time practical support, inhalation therapy, and off-label sedative medication may improve QOL. Curative therapy may reduce QOL.

IMPACT

QOL for children at the end of life may be improved with patient-controlled symptom feedback, multidisciplinary palliative care teams with full-time practical support, inhalation therapy, and off-label sedative medication. QOL for children at the end of life may be reduced with therapy with a curative intent, such as curative chemotherapy or stem cell transplant. A comprehensive overview of current evidence to elevate currently often-failing QOL management for children at the end of life. New paradigm-level indicators for appropriate and inappropriate QOL management in children at the end of life. New hypotheses for future research, guided by the current knowledge within the field. Various healthcare interventions (as described above) could or might be employed as tools to provide relief in QOL management for children with serious illness, such as cancer, at the end of life, and therefore could be discussed in pediatrician end-of-life training to limit the often-failed QOL management in this population, cave the one-size-fits-all approach for individual cases. Multidisciplinary team efforts and 24/7 presence, especially practical support for parents, might characterize effective palliative care team interventions for children with serious illness at the end of life, suggesting a co-regulating link between well-being of the child partly to that of the parents Hypothesis-oriented research is needed, especially for children with nonmalignant disorders, such as genetic or neurological disorders at the end of life, as well as QOL outcomes for intervention research and psychosocial or spiritual outcomes.

A review of the clinical applications of ketamine in pediatric oncology

Ketamine is a dissociative anesthetic agent with excellent analgesic properties and a favorable safety profile. The feasibility and efficacy of various routes of administration have been established, including intravenous (IV), intramuscular (IM), oral, intranasal, rectal, and transdermal routes. The advent of newer anesthetic agents has led to a decline in the use of ketamine as an anesthetic, but its utility in short-term sedation and analgesia has expanded. Its value for chronic pain management in children with cancer is being increasingly recognized but requires more evidence. The use of topical ketamine is largely in investigational stages. Medical use of ketamine is, to a great extent, free from significant long-term neurological side effects. The objective of this review is to provide a brief account of the pharmacology of ketamine and primarily focus on the clinical applications of ketamine in pediatric oncology.

Ketamine applications beyond anesthesia - A literature review

Ketamine's clinical use began in the 1970s. Physicians benefited from its safety and ability to induce short-term anesthesia and analgesia. The psychodysleptic effects caused by the drug called its further clinical use into question. Despite these unpleasant effects, ketamine is still applied in veterinary medicine, field medicine, and specialist anesthesia. Recent intensive research brought into light new possible applications of this drug. It began to be used in acute, chronic and cancer pain management. Most interesting reports come from research on the antidepressive and antisuicidal properties of ketamine giving hope for the creation of an effective treatment for major depressive disorder. Other reports highlight the possible use of ketamine in treating addiction, asthma and preventing cancer growth. Besides clinical use, the drug is also applied to in animal model of schizophrenia. It seems that nowadays, with numerous possible applications, the use of ketamine has returned; to its former glory. Nevertheless, the drug must be used with caution because still the mechanisms by which it executes its functions and long-term effects of its use are not fully known. This review aims to discuss the well-known and new promising applications of ketamine.

Neuropathic Pain in Pediatric Oncology: A Clinical Decision Algorithm

Neuropathic pain in pediatric oncology can be caused by distinct lesions or disease processes affecting the somatosensory system, including chemotherapy-related neuronal injury, solid tumor-related involvement of neural structures, post-surgical neuropathic pain-including phantom limb pain and pain after limb-sparing surgery-and the complex circumstances of neuropathic pain at the end of life. Treatment algorithms reflect the general treatment principles applied for adult neuropathic pain, but the dose regimens applied in children are modest and rarely escalated to the maximum doses to optimize analgesic efficacy. Pharmacological management of neuropathic pain should be based on a stepwise intervention strategy, as combinations of medications are the most effective approach. Gabapentinoids and tricyclic antidepressants are recommended as first-line therapy. Methadone, ketamine, and lidocaine may be useful adjuvants in selected patients. Prospective studies extended over a substantial length of time are recommended because of the nature of neuropathic pain as persistent, chronic pain and based on the need for sufficient time to escalate medication dose regimens to full analgesic efficacy.

Consensus Guidelines on the Use of Intravenous Ketamine Infusions for Acute Pain Management From the American Society of Regional Anesthesia and Pain Medicine, the American Academy of Pain Medicine, and the American Society of Anesthesiologists

BACKGROUND

Ketamine infusions have been used for decades to treat acute pain, but a recent surge in usage has made the infusions a mainstay of treatment in emergency departments, in the perioperative period in individuals with refractory pain, and in opioid-tolerant patients. The widespread variability in patient selection, treatment parameters, and monitoring indicates a need for the creation of consensus guidelines.

METHODS

The development of acute pain ketamine guidelines grew as a corollary from the genesis of chronic pain ketamine guidelines. The charge for the development of acute pain ketamine guidelines was provided by the Boards of Directors of both the American Society of Regional Anesthesia and Pain Medicine and the American Academy of Pain Medicine, who approved the document along with the American Society of Anesthesiologists' Committees on Pain Medicine and Standards and Practice Parameters. The committee chair developed questions based on input from the committee during conference calls, which the committee then refined. Groups of 3 to 5 panel members and the committee chair were responsible for answering individual questions. After preliminary consensus was achieved, the entire committee made further revisions via e-mail and conference calls.

RESULTS

Consensus guidelines were prepared in the following areas: indications, contraindications for acute pain and whether they differ from those for chronic pain, the evidence for the use of ketamine as an adjunct to opioid-based therapy, the evidence supporting patient-controlled ketamine analgesia, the use of nonparenteral forms of ketamine, and the subanesthetic dosage range and whether the evidence supports those dosages for acute pain. The group was able to reach consensus on the answers to all questions.

CONCLUSIONS

Evidence supports the use of ketamine for acute pain in a variety of contexts, including as a stand-alone treatment, as an adjunct to opioids, and, to a lesser extent, as an intranasal formulation. Contraindications for acute pain are similar to those for chronic pain, partly based on the observation that the dosage ranges are similar. Larger studies evaluating different acute pain conditions are needed to enhance patient selection, determine the effectiveness of nonparenteral ketamine alternatives, define optimal treatment parameters, and develop protocols optimizing safety and access to care.

Ketamine for cancer pain: what is the evidence?

PURPOSE OF REVIEW

In this review, we assess the benefit of ketamine in the treatment of terminal cancer pain that is refractory to opioid treatment and/or complicated by neuropathy.

RECENT FINDINGS

While randomized controlled trials consistently show lack of clinical efficacy of ketamine in treating cancer pain, a large number of open-label studies and case series show benefit.

SUMMARY

Ketamine is an N-methyl-D-aspartate receptor antagonist that at low-dose has effective analgesic properties. In cancer pain, ketamine is usually prescribed as adjuvant to opioid therapy when pain becomes opioid resistant or when neuropathic pain symptoms dominate the clinical picture. A literature search revealed four randomized controlled trials that examined the benefit of oral, subcutaneous or intravenous ketamine in opioid refractory cancer pain. None showed clinically relevant benefit in relieving pain or reducing opioid consumption. This suggests absence of evidence of benefit for ketamine as adjuvant analgesic in cancer pain. These findings contrast the benefit from ketamine observed in a large number of open-label studies and (retrospective) case series. We relate the opposite outcomes to methodological issues. The complete picture is such that there is still insufficient evidence to state with certainty that ketamine is not effective in cancer pain.

End-of-Life and Bereavement Care in Pediatric Intensive Care Units

Most childhood deaths in the United States occur in hospitals. Pediatric intensive care clinicians must anticipate and effectively treat dying children's pain and suffering and support the psychosocial and spiritual needs of families. These actions may help family members adjust to their loss, particularly bereaved parents who often experience reduced mental and physical health. Candid and compassionate communication is paramount to successful end-of-life (EOL) care as is creating an environment that fosters meaningful family interaction. EOL care in the pediatric intensive care unit is associated with challenging ethical issues, of which clinicians must maintain a sound and working understanding.

Subanesthetic ketamine infusions for the treatment of children and adolescents with chronic pain: a longitudinal study

BACKGROUND

Chronic pain is common in children and adolescents and is often associated with severe functional disability and mood disorders. The pharmacological treatment of chronic pain in children and adolescents can be challenging, ineffective, and is mostly based on expert opinions and consensus. Ketamine, an N-methyl-D-aspartate receptor antagonist, has been used as an adjuvant for treatment of adult chronic pain and has been shown, in some instances, to improve pain and decrease opioid-requirement. We examined the effects of subanesthetic ketamine infusions on pain intensity and opioid use in children and adolescents with chronic pain syndromes treated in an outpatient setting.

METHODS

Longitudinal cohort study of consecutive pediatric patients treated with subanesthetic ketamine infusions in a tertiary outpatient center. Outcome measurements included self-reported pain scores (numeric rating scale) and morphine-equivalent intake.

RESULTS

Over a 15-month period, 63 children and adolescents (median age 15, interquartile range 12-17 years) with chronic pain received 277 ketamine infusions. Intravenous administration of subanesthetic doses of ketamine to children and adolescents on an outpatient basis was safe and not associated with psychotropic effects or hemodynamic perturbations. Overall, ketamine significantly reduced pain intensity (p < 0.001) and yielded greater pain reduction in patients with complex regional pain syndrome (CRPS) than in patients with other chronic pain syndromes (p = 0.029). Ketamine-associated reductions in pain scores were the largest in postural orthostatic tachycardia syndrome (POTS) and trauma patients and the smallest in patients with chronic headache (p = 0.007). In 37% of infusions, patients had a greater than 20 % reduction in pain score. Conversely, ketamine infusions did not change overall morphine-equivalent intake (p = 0.3).

CONCLUSIONS

These data suggest that subanesthetic ketamine infusion is feasible in an outpatient setting and may benefit children and adolescents with chronic pain. Further, patients with CRPS, POTS, and a history of trauma-related chronic pain are more likely to benefit from this therapeutic modality.