Narcotic reversal in hypercapnic dogs: comparison of naloxone and nalbuphine

Acute Lung Injury As Severe Acute Respiratory Distress Syndrome After Fentanyl Overdose

Acute lung injury following fentanyl overdose is an unusual presentation. Pulmonary edema has been associated with opioid and naloxone use. However, to our knowledge, there have been no previous reports of inhaled fentanyl-associated acute lung injury presenting with acute hypoxic respiratory failure secondary to severe acute respiratory distress syndrome. We report a case of inhaled fentanyl-related severe acute respiratory distress syndrome which presented immediately after snorting fentanyl. This patient developed hypoxia requiring 100% oxygen on non-rebreather mask, and acute respiratory distress syndrome was confirmed on chest X-ray and computed tomography on admission. He was successfully treated with steroids with recovery in 48 hours. Naloxone was used in this patient, which has been associated with pulmonary edema in case reports and series, but clinical findings were more consistent with acute respiratory distress syndrome rather than pulmonary edema. The mechanism for this clinical presentation is not well known. Proposed mechanisms include lung injury from inhalation against an obstruction in a manner similar to post-obstructive pulmonary edema. Although our patient rapidly responded to symptomatic treatment and steroid course, our case also highlights the need for further study to elucidate the various clinical presentations associated with fentanyl use-related lung toxicity including acute respiratory distress syndrome.

High-flow nasal cannula oxygen therapy in the management of acute respiratory distress syndrome secondary to opioid overdose

In this article, we discuss the successful treatment of acute respiratory distress syndrome (ARDS), a rare complication of opioid overdose, through high-flow nasal cannula oxygen therapy (HFNCOT). A 32-year-old male patient was referred to the emergency department with an ambulance due to a state of confusion following intravenous opioid intake. On arrival, the patient had an arterial blood pressure of 100/60 mmHg, pulse of 112 beats/min, respiratory rate of 8 breaths/min, and oxygen saturation (SpO₂) of 75%. On neurologic examination, he had miotic and isochoric pupils, and Glasgow Coma Score was 12 (E: 3 M: 5 V: 4). Cardiac examination showed that the heart was rhythmic and tachycardic. Chest examination revealed bibasilar crackles and wheezing. Naloxone was administered to the patient, and oxygen treatment was applied through a mask. Then, HFNCOT was commenced to the patient in whom the PaO₂/FiO₂ ratio in the blood gas was calculated as 141 following antidote treatment and whose chest radiograph showed bilateral infiltrations. The patient was discharged from the emergency critical care unit on the 3^rd day of his hospitalization because infiltrations in his chest radiograph regressed. HFNCOT can recover the patient's hypoxemia and help reduce the necessity of mechanical ventilation in patients with mild or moderate ARDS.

Substance Use Disorders in Vulnerable Children

Substance use remains a major challenge in adolescent health. The coexisting use of these substances often creates hurdles for accurate diagnosis of other comorbid psychiatric conditions. It is of critical importance that health care providers be aware of both the isolated presentation of substance use disorder and that with coexisting psychiatric illness in vulnerable children.

Effect of three doses of nalbuphine on reversal of sedation and cardiopulmonary effects of morphine-acepromazine in healthy dogs

OBJECTIVE

To evaluate the efficacy of three doses of nalbuphine in reversing sedative and cardiopulmonary effects of morphine-acepromazine in dogs.

STUDY DESIGN

Prospective, randomized experimental trial.

ANIMALS

A group of eight healthy Beagle dogs, aged 5-6 years and weighing 12.5 ± 2.1 kg.

METHODS

Dogs were administered morphine (0.5 mg kg^-1) and acepromazine (0.05 mg kg^-1) intravenously (IV). After 20 minutes, dogs were administered one of four treatments IV: saline (control); or nalbuphine (0.3 mg kg^-1; treatment N0.3), (0.6 mg kg^-1; treatment N0.6) or (1.0 mg kg^-1; treatment N1.0), in random order separated by 1 week. Sedation was scored using a numeric descriptive scale (NDS) and simple numerical scale (SNS). Heart rate, systolic arterial pressure (SAP), respiratory rate (f_R) and rectal temperature (RT) were recorded before (BL), 20 minutes after morphine-acepromazine (T0), then 10 (T10), 30, 60 and 90 minutes after saline or nalbuphine. Arterial blood gases were measured at BL, T0 and T10. Values were compared with BL, T0 and among treatments using anova (p < 0.05) and the Bonferroni correction (p < 0.008).

RESULTS

NDS for N0.6 and SNS for N0.6 and N1.0 at T30, and both scores for all nalbuphine treatments at T60-T90 were lower compared with T0 (p < 0.05). Sedation scores were not different among nalbuphine treatments. SNS scores were lower than control at T10 for N0.3 and N0.6 (p < 0.05). SAP and f_R were lower than BL for all treatments at some time points (p < 0.05). RT was higher than control at T60 in the nalbuphine treatments (p < 0.001). PaO₂ was lower in N0.3 at T0 compared with BL (p = 0.036).

CONCLUSIONS AND CLINICAL RELEVANCE

All nalbuphine doses decreased the degree of sedation, without differences among them. Administration of nalbuphine resulted in minimal changes in measured cardiopulmonary variables.

ECMO used successfully in a near fatal case of opioid-induced acute respiratory distress syndrome

Acute Respiratory Distress Syndrome (ARDS) was first recognized during the 1960s. It is a distinct type of hypoxemic respiratory failure characterized by acute abnormality of both lungs. Extracorporeal membrane oxygenation (ECMO) is being increasingly used for patients with severe ARDS refractory to otherwise conventional management. A 29year old male arrived with Emergency Medical Services (EMS) status post presumed heroin overdose. He was administered Naloxone 2mg intravenously prior to arrival in the emergency department. The patient arrived in severe respiratory distress with a pulse oximetry level of 50% and was immediately intubated. The patient's pulse oximetry level remained in the seventies despite intubation and aggressive ventilator management. The Intensive Care Unit team in conjunction with cardiothoracic surgery initiated venovenous ECMO therapy in the emergency department itself. The patient was transferred to a tertiary center for venoarterial ECMO that was continued for 6 more days. After an extensive hospitalization, the patient was ultimately transferred to an acute medical rehabilitation center. With the current opioid crisis, emergency physicians and providers need to be aware that opioids can induce severe ARDS refractory to mechanical ventilation. ECMO as a treatment option can be used safely and successfully as described in this unique patient case report.

Cardiorespiratory Effects of Naloxone in Children

BACKGROUND:

Data on the cardiorespiratory changes and complications following administration of naloxone in children are limited.

OBJECTIVE:

To evaluate the cardiorespiratory changes and complications following naloxone treatment in children.

METHODS:

The maximal changes in respiratory rate (RR), heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure, and any complications within 1 and 2 hours following naloxone were tabulated.

RESULTS:

One hundred ninety-five children received naloxone over 3 years. The mean ± SD age was 9.7 ± 6 years. The total doses of naloxone ranged from 0.01 to 7 mg (0.001–0.5 mg/kg body weight), with a median dose of 0.1 mg. Group 1 patients consisted of 11 6 (60%) children who were postoperative and had been given naloxone by an anesthesiologist; group 2 patients consisted of 79 (40%) children who received naloxone in the emergency department or pediatric intensive care unit. Patients in group 1 were older: 10.6 ± 5.3 versus 8.2 ± 6.7 years (p < 0.006), but received significantly lower doses of naloxone (0.09 ± 0.2 vs. 1.1 ± 0.76 mg; p < 0.001). When the entire cohort was evaluated, a significant increase in RR (15 ± 7 vs. 21 ± 8 breaths/min; p < 0.001), HR (102 ± 29 vs.107 ± 29 beats/min; p < 0.001), SBP (109 ± 17 vs. 115 ± 15 mm Hg; p < 0.001), and DBP (56 ± 10 vs. 60 ± 13 mm Hg; p < 0.001) within 1 hour following naloxone was noted. When the 2 groups were compared, only the changes in RR were greater in group 2 patients (6.8 ± 7.9 vs. 4.7 ± 5 breaths/min; p < 0.001) following naloxone. Systolic hypertension occurred in 33 of 195 (16.9%) of all patients, while diastolic hypertension occurred in 13 (6.6%) of all patients after naloxone. Only the incidence of diastolic hypertension was higher in group 2 compared with group 1 patients following naloxone (16% vs. 2%; p < 0.001). Hypertension resolved spontaneously. One child developed pulmonary edema and required positive pressure ventilation for 22 hours.

CONCLUSIONS:

Moderate increases in RR, HR, and BP occur after naloxone administration to children, but development of more serious complications is rare.

Analysis of the transport of and cytotoxic effects for nalbuphine solution in corneal cells

OBJECTIVE

To assess the in vitro effects of various nalbuphine concentrations on viability and wound healing ability of corneal cells and potential drug transport through the corneal epithelium.

SAMPLE

Cultured canine and human corneal epithelial cells (CECs) and cultured canine corneal stromal fibroblasts.

PROCEDURES

CECs and stromal fibroblasts were exposed to nalbuphine (concentration of solutions ranged from 0% to 1.2%) for up to 30 minutes, and viability was assessed with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. A standard scratch test technique was used. Wound healing of CECs and stromal fibroblasts was evaluated following treatment with nalbuphine solutions < 0.1%. Liquid chromatography-mass spectrometry-mass spectrometry analysis was used to evaluate drug transport across a monolayer and a multilayer of human CECs.

RESULTS

A progressive decrease in viability was detected in canine CECs for all nalbuphine treatment groups, whereas treatment with only 0.5% or 1.2% nalbuphine significantly reduced corneal stromal fibroblast viability, compared with results for control cells. Within 24 hours, treatment with 0.1% nalbuphine solution significantly altered the healing rate of both canine CECs and stromal fibroblasts. Continuous increases in transport rates of nalbuphine were detected with time for both the monolayer and multilayer of human CECs.

CONCLUSIONS AND CLINICAL RELEVANCE

In vitro, nalbuphine potentially could penetrate through corneal tissue, but it may cause damage to the corneal epithelium and stromal fibroblasts. Therefore, nalbuphine potentially may impair corneal wound healing.

Pulmonary hemorrhage: a rare complication of opioid overdose

Children and adolescents with pulmonary hemorrhage are infrequently encountered in the emergency department (ED). We describe a case of a 16 year-old boy who presented to a pediatric ED with pulmonary hemorrhage and respiratory distress. The patient's unusual initial presentation resulted in the consideration of a broad differential diagnosis for his symptoms, including traumatic, neurological, respiratory, and toxicological causes. After resuscitation in the ED, a prolonged admission, and extensive testing, no cause could be found other than severe opioid toxicity. This case illustrates a rare, life-threatening presentation of opiod toxicity in a healthy adolescent and underlines the potentially serious nature of such exposures.

Drugs and pharmaceuticals: management of intoxication and antidotes

The treatment of patients poisoned with drugs and pharmaceuticals can be quite challenging. Diverse exposure circumstances, varied clinical presentations, unique patient-specific factors, and inconsistent diagnostic and therapeutic infrastructure support, coupled with relatively few definitive antidotes, may complicate evaluation and management. The historical approach to poisoned patients (patient arousal, toxin elimination, and toxin identification) has given way to rigorous attention to the fundamental aspects of basic life support--airway management, oxygenation and ventilation, circulatory competence, thermoregulation, and substrate availability. Selected patients may benefit from methods to alter toxin pharmacokinetics to minimize systemic, target organ, or tissue compartment exposure (either by decreasing absorption or increasing elimination). These may include syrup of ipecac, orogastric lavage, activated single- or multi-dose charcoal, whole bowel irrigation, endoscopy and surgery, urinary alkalinization, saline diuresis, or extracorporeal methods (hemodialysis, charcoal hemoperfusion, continuous venovenous hemofiltration, and exchange transfusion). Pharmaceutical adjuncts and antidotes may be useful in toxicant-induced hyperthermias. In the context of analgesic, anti-inflammatory, anticholinergic, anticonvulsant, antihyperglycemic, antimicrobial, antineoplastic, cardiovascular, opioid, or sedative-hypnotic agents overdose, N-acetylcysteine, physostigmine, L-carnitine, dextrose, octreotide, pyridoxine, dexrazoxane, leucovorin, glucarpidase, atropine, calcium, digoxin-specific antibody fragments, glucagon, high-dose insulin euglycemia therapy, lipid emulsion, magnesium, sodium bicarbonate, naloxone, and flumazenil are specifically reviewed. In summary, patients generally benefit from aggressive support of vital functions, careful history and physical examination, specific laboratory analyses, a thoughtful consideration of the risks and benefits of decontamination and enhanced elimination, and the use of specific antidotes where warranted. Data supporting antidotes effectiveness vary considerably. Clinicians are encouraged to utilize consultation with regional poison centers or those with toxicology training to assist with diagnosis, management, and administration of antidotes, particularly in unfamiliar cases.

The resurgence and abuse of heroin by children in the United States

Heroin, one of the most addictive and "hardest" drugs of abuse, carries significant morbidity and mortality. Although its use is usually associated with the adult population in the United States, the last decade has witnessed a decrease in the median age of heroin users. An increase in the availability of inexpensive and pure heroin that could be snorted rather than injected made the drug accessible to adolescents and reduced the fear associated with the transmission of the human immunodeficiency virus (HIV). Because of the atypical demographics and the alternative drug use patterns, this young population of heroin users is not easily identified by parents or by healthcare providers. Lack of social support or access to healthcare prevents young heroin users from participation in detoxification programs, suggesting that changes may be needed in our healthcare and social systems to properly target and provide care to the youngest heroin abusers.

Opioid antagonists: a review of their role in palliative care, focusing on use in opioid-related constipation

Opioid antagonists have well-established indications in the reversal of life-threatening opioid toxicity, but also hold considerable promise for other applications in palliative care practice, particularly management of opioid-related constipation. We briefly review current understanding of opioid receptors, focusing on their complex role in gastrointestinal physiology. We summarize the pharmacology, conventional indications, and clinical usage of three major groups of opioid antagonists, including a promising new peripherally acting agent, methylnaltrexone, which is not commercially available. We suggest an approach to administering opioid antagonists for reduction of life-threatening opioid toxicity in patients with pain. The literature on opioid-induced constipation and its treatment with opioid-antagonists is reviewed in detail. Finally, other potential uses of opioid antagonists in palliative care are described, especially strategies for reducing such opioid side effects as nausea and pruritus and for improving analgesia or reducing tolerance by concomitantly administrating both an opioid agonist and low dosages of an antagonist.

Nalbuphine coadministered with morphine prevents tolerance and dependence

Nalbuphine, an opioid mixed agonist-antagonist, prevents many morphine-related side effects. In this study, we compared the effects of nalbuphine versus naloxone on the prevention of morphine tolerance and dependence in Sprague-Dawley rats. Group 1 received a morphine 5 mg/kg intraperitoneal (I.P.) injection. Groups 2 and 3 received single doses of nalbuphine (0.01 to 5 mg/kg I.P.) or naloxone (1 to 500 microg/kg I.P.) coadministered with morphine (5 mg/kg I.P.), respectively. Group 4 received a saline I.P. injection. Treatments were continued for 4 days. The occurrence of tolerance was estimated by comparing the antinociceptive effect of morphine on Day 1 (Group 1) and Day 5 (each group). The severity of dependence was determined by precipitated withdrawal signs (incidence of diarrhea and teeth chattering) induced by naloxone (10 mg/kg I.P.). We found that coadministration of nalbuphine or naloxone with morphine dose-dependently blocked the development of morphine tolerance and dependence. However, unlike naloxone, nalbuphine did not attenuate the antinociceptive effect of morphine.

Cardiorespiratory effects of four opioid-tranquilizer combinations in dogs

The cardiorespiratory effects of four opioid-tranquilizer combinations were evaluated in six dogs. The four combinations were administered to each dog in a randomized order. Buprenorphine (BUP; 0.01 mg/kg IV) or oxymorphone (OXY; 0.1 mg/kg IV) was followed in 10.4 +/- 1.3 minutes by midazolam (MID; 0.3 mg/kg IV) or acepromazine (ACE; 0.05 mg/kg IV). Nalbuphine (0.16 mg/kg IV) was administered 94.1 +/- 2.3 minutes after the tranquilizer was given. Heart rate (HR) and mean arterial blood pressure (MAP) decreased significantly (P < .05) after each combination. MAP was significantly lower with combinations using ACE. Most dogs panted after opioid administration; this was associated with increased minute volume (VM) and decreased tidal volume (VT). After administration of the tranquilizer, mean breathing rate and VM index (VMI) were significantly lower with ACE combinations. There were no significant changes in pH and blood gas variables after BUP-ACE. The other three combinations were associated with significant (P < .05) decreases in pH and increases in PaCO2. Mean PaO2 decreased significantly (P < .05) with OXY combinations but not BUP combinations. Dysrhythmias (atrial or ventricular escape complexes) were seen with each combination. HR increased significantly (P < .05) after nalbuphine in dogs receiving OXY, but not BUP. Dogs receiving OXY became more alert after nalbuphine on six of 12 occasions, whereas dogs receiving BUP became less alert on six of 12 occasions. OXY-ACE provided the most chemical restraint/sedation and BUP-MID provided the least.