Three cases with different presentation of fentanyl-induced muscle rigidity--a rare problem in intensive care of neonates

Fentanyl-Induced Rigid Chest Syndrome in Critically Ill Patients

BACKGROUND

Opioid induced chest wall rigidity was first described in the early 1950s during surgical anesthesia and has often been referred to as fentanyl induced rigid chest syndrome (FIRCS). It has most commonly been described in the setting of procedural sedation and bronchoscopy, characterized by pronounced abdominal and thoracic rigidity, asynchronous ventilation, and respiratory failure. FIRCS has been infrequently described in the setting of continuous analgesia in critically ill adult patients. We postulate that FIRCS can occur in this setting and is likely under recognized, leading to increased morbidity and mortality.

METHODS

Patients admitted to the intensive care unit with suspected FIRCS were included in this retrospective analysis. The objective of this analysis is to describe the clinical presentation and treatment strategies for FIRCS.

RESULTS

Forty-two patients exhibiting symptoms of FIRCS were included in this analysis. Twenty-two of the forty-two patients with descriptive documentation had evidence of thoracic or abdominal rigidity on examination (52.4%). Twelve of sixteen (75%) patients treated solely with naloxone had documented ventilator compliance following intervention, compared to six of eleven (55%) managed with cisatracurium alone. Nine of twelve patients who ultimately received naloxone after initial treatment with cisatracurium had documented ventilator compliance following naloxone administration (75%). Standard interventions, including sedation optimization and ventilator adjustments were attempted to rule out and treat other potential causes of dyssynchrony. In most cases, the administration of naloxone resulted in appropriate compliance with both ventilator and patient-initiated breaths, suggesting the ventilator dyssynchrony was due to fentanyl.

CONCLUSIONS

This is the largest case series to date describing FIRCS in the intensive care setting. Recognition and prompt management is necessary for improved patient outcomes. Research is needed to increase awareness and recognition, identify patient risk factors, and analyze the efficacy and safety of interventions.

Zebrafish early life stages as alternative model to study 'designer drugs': Concordance with mammals in response to opioids

The number of new psychoactive substances (NPS) on the illicit drug market increases fast, posing a need to urgently understand their toxicity and behavioural effects. However, with currently available rodent models, NPS assessment is limited to a few substances per year. Therefore, zebrafish (Danio rerio) embryos and larvae have been suggested as an alternative model that would require less time and resources to perform an initial assessment and could help to prioritize substances for subsequent evaluation in rodents. To validate this model, more information on the concordance of zebrafish larvae and mammalian responses to specific classes of NPS is needed. Here, we studied toxicity and behavioural effects of opioids in zebrafish early life stages. Synthetic opioids are a class of NPS that are often used in pain medication but also frequently abused, having caused multiple intoxications and fatalities recently. Our data shows that fentanyl derivatives were the most toxic among the tested opioids, with toxicity in the zebrafish embryo toxicity test decreasing in the following order: butyrfentanyl>3-methylfentanyl>fentanyl>tramadol> O-desmethyltramadol>morphine. Similar to rodents, tramadol as well as fentanyl and its derivatives led to hypoactive behaviour in zebrafish larvae, with 3-methylfentanyl being the most potent. Physico-chemical properties-based predictions of chemicals' uptake into zebrafish embryos and larvae correlated well with the effects observed. Further, the biotransformation pattern of butyrfentanyl in zebrafish larvae was reminiscent of that in humans. Comparison of toxicity and behavioural responses to opioids in zebrafish and rodents supports zebrafish as a suitable alternative model for rapidly testing synthetic opioids.

In-vivo tongue stiffness measured by aspiration: Resting vs general anesthesia

Tongue cancer treatment often results in impaired speech, swallowing, or mastication. Simulating the effect of treatments can help the patient and the treating physician to understand the effects and impact of the intervention. To simulate deformations of the tongue, identifying accurate mechanical properties of tissue is essential. However, not many succeeded in characterizing in-vivo tongue stiffness. Those who did, measured the tongue At Rest (AR), in which muscle tone subsides even if muscles are not willingly activated. We expected to find an absolute rest state in participants 'under General Anesthesia' (GA). We elaborated on previous work by measuring the mechanical behavior of the in-vivo tongue under aspiration using an improved volume-based method. Using this technique, 5 to 7 measurements were performed on 10 participants both AR and under GA. The obtained Pressure-Shape curves were first analyzed using the initial slope and its variations. Hereafter, an inverse Finite Element Analysis (FEA) was applied to identify the mechanical parameters using the Yeoh, Gent, and Ogden hyperelastic models. The measurements AR provided a mean Young's Modulus of 1638 Pa (min 1035 - max 2019) using the Yeoh constitutive model, which is in line with previous ex-vivo measurements. However, while hoping to find a rest state under GA, the tongue unexpectedly appeared to be approximately 2 to 2.5 times stiffer under GA than AR. Explanations for this were sought by examining drugs administered during GA, blood flow, perfusion, and upper airway reflexes, but neither of these explanations could be confirmed.

Rigidity, dyskinesia and other atypical overdose presentations observed at a supervised injection site, Vancouver, Canada

Objective

In midst of the overdose crisis, the clinical features of opioid overdoses seem to be changing. Understanding of the adverse effects of synthetic opioids such as fentanyl is currently limited to clinical settings. Insite, a supervised injection site in Vancouver, Canada, provides an opportunity to better understand illicit drug overdose presentations.

Methods

A review of clinical records at Insite for October 2016 to April 2017 was undertaken to quantify atypical overdose presentations. Overdose reports were reviewed for the number of atypical opioid overdose presentations, temporal trends over the study period, concurrent symptoms, and interventions employed by staff.

Results

Insite staff responded to 1581 overdoses during the study period, including 497 (31.4%) that did not fit a typical presentation for opioid overdoses. Of these, 485 fit into five categories of atypical features: muscle rigidity, dyskinesia, slow or irregular heart rate, confusion, and anisocoria. Muscle rigidity was the most common atypical presentation, observed in 240 (15.2%) of the overdose cases, followed by dyskinesia, observed in 150 (9.2%). Slow or irregular heart rate was observed in 69 (4.4%) cases, confusion in 24 (1.5%), and anisocoria in 2 (0.1%) of overall overdose cases.

Discussion

The similarity of atypical overdose cases at Insite with anesthesiology case reports supports the understanding that the illicit drug supply is contaminated by fentanyl and other synthetic opioids. Atypical overdose presentations can affect clinical overdose response. The experience at Insite highlights the potential for supervised consumption sites to be innovative spaces for community learning and knowledge translation.

Fentanyl-induced chest wall rigidity

Fentanyl and other opiates used in procedural sedation and analgesia are associated with several well-known complications. We report the case of a man who developed the uncommon complication of chest wall rigidity and ineffective spontaneous ventilation following the administration of fentanyl during an elective bronchoscopy. His ventilation was assisted and the condition was reversed with naloxone. Although this complication is better described in pediatric patients and with anesthetic doses, chest wall rigidity can occur with analgesic doses of fentanyl and related compounds. Management includes ventilatory support and reversal with either naloxone or a short-acting neuromuscular blocking agent. This reaction does not appear to be a contraindication to future use of fentanyl or related compounds. Chest wall rigidity causing respiratory compromise should be readily recognized and treated by bronchoscopists.

Procedural sedation: A review of sedative agents, monitoring, and management of complications

Given the continued increase in the complexity of invasive and noninvasive procedures, healthcare practitioners are faced with a larger number of patients requiring procedural sedation. Effective sedation and analgesia during procedures not only provides relief of suffering, but also frequently facilitates the successful and timely completion of the procedure. However, any of the agents used for sedation and/or analgesia may result in adverse effects. These adverse effects most often affect upper airway patency, ventilatory function or the cardiovascular system. This manuscript reviews the pharmacology of the most commonly used agents for sedation and outlines their primary effects on respiratory and cardiovascular function. Suggested guidelines for the avoidance of adverse effects through appropriate pre-sedation evaluation, early identification of changes in respiratory and cardiovascular function, and their treatment are outlined.

Chest wall rigidity in two infants after low-dose fentanyl administration

Since its introduction into clinical practice, it has been known that fentanyl and other synthetic opioids may cause skeletal muscle rigidity. Involvement of the respiratory musculature, laryngeal structures, or the chest wall may impair ventilation, resulting in hypercarbia and hypoxemia. Although most common with the rapid administration of large doses, this rare adverse effect may occur with small doses especially in neonates and infants. We present 2 infants who developed chest wall rigidity, requiring the administration of neuromuscular blocking agents and controlled ventilation after analgesic doses of fentanyl. Previous reports regarding chest wall rigidity after the administration of low-dose fentanyl in infants and children are reviewed, the pathogenesis of the disorder is discussed, and treatment options offered.

Analgesia and sedation during mechanical ventilation in neonates

BACKGROUND

Endotracheal intubation and mechanical ventilation are major components of routine intensive care for very low birth weight newborns and sick full-term newborns. These procedures are associated with physiologic, biochemical, and clinical responses indicating pain and stress in the newborn. Most neonates receive some form of analgesia and sedation during mechanical ventilation, although there are marked variations in clinical practice. Clinical guidelines for pharmacologic analgesia and sedation in newborns based on robust scientific data are lacking, as are measures of clinical efficacy.

OBJECTIVE

This article represents a preliminary attempt to develop a scientific rationale for analgesia sedation in mechanically ventilated newborns based on a systematic analysis of published clinical trials.

METHODS

The current literature was reviewed with regard to the use of opioids (fentanyl, morphine, diamorphine), sedative-hypnotics (midazolam), nonsteroidal anti-inflammatory drugs (ibuprofen, indomethacin), and acetaminophen in ventilated neonates. Original meta-analyses were conducted that collated the data from randomized clinical comparisons of morphine or fentanyl with placebo, or morphine with fentanyl.

RESULTS

The results of randomized trials comparing fentanyl, morphine, or midazolam with placebo, and fentanyl with morphine were inconclusive because of small sample sizes. Meta-analyses of the randomized controlled trials indicated that morphine and fentanyl can reduce behavioral and physiologic measures of pain and stress in mechanically ventilated preterm neonates but may prolong the duration of ventilation or produce other adverse effects. Randomized trials of midazolam compared with placebo reported significant adverse effects (P < 0.05) and no apparent clinical benefit; the findings of a meta-analysis suggest that there are insufficient data to justify use of IV midazolam for sedation in ventilated neonates.

CONCLUSIONS

Despite ongoing research in this area, huge gaps in our knowledge remain. Well-designed and adequately powered clinical trials are needed to establish the safety, efficacy, and short- and long-term outcomes of analgesia and sedation in the mechanically ventilated newborn.

Patient-controlled modalities for acute postoperative pain management

Although numerous clinical practice guidelines for pain management have been published throughout the last 12 years, inadequate pain relief remains a significant health care issue. Several patient-controlled analgesia (PCA) modalities are currently available for the treatment of acute postoperative pain, including intravenous (IV) PCA, epidural (PCEA), and oral PCA. Although PCEA and IV PCA are both commonly used modalities, IV PCA is considered the standard of care for postoperative pain management. Limitations of this modality do exist, however. Consequently, noninvasive PCA systems are under development to circumvent many of these limitations, including the fentanyl hydrochloride patient-controlled transdermal system (PCTS); (IONSYS Ortho-McNeil Pharmaceutical, Raritan, NJ) and a number of patient-controlled intranasal analgesia (PCINA) delivery systems. The objective of this article is to review the PCA modalities currently in use and to discuss those in development for the treatment of acute postoperative pain.

Adverse effects of sedatives in children

The application of sedation/analgesia in paediatric patients is rapidly expanding as less invasive, non-operative techniques of diagnosis and treatment are applied to the paediatric population. Medical providers who are asked to provide sedation may include radiologists, paediatricians, nurses and emergency physicians, as well as anaesthesiologists and intensive care physicians. At the same time, the range of drugs used in these settings has expanded considerably. As there is no single drug fulfilling the criteria for the ideal sedative (rapid-onset, rapid recovery, no adverse effects, immobility appropriate to procedure being performed), multiple drugs may be used in combination. It is imperative that practitioners using drugs for sedation/analgesia in children be aware of the adverse effect profile(s) of these drugs, both individually and in combination. The purpose of this review is to describe the adverse effects of sedative and reversal agents currently used in paediatric sedation/analgesia.