Paradoxical reaction to midazolam reversed with flumazenil

A blinded crossover study design to evaluate midazolam as an adjunct for equine standing sedation for routine oral examinations

This study aimed to evaluate the effects of including midazolam to a common equine standing sedation protocol for routine oral examination. Twelve horses underwent two examinations at least seven days apart. Horses were randomly assigned to receive midazolam intravenously (IV) (0.02mg/kg) or a placebo injection of saline (2-2.5mL IV). Five minutes later, detomidine (0.01mg/kg) and butorphanol (0.01mg/kg) were administered IV and horses were placed in standing stocks. A veterinarian blinded to the treatment protocol used a descriptive scoring system to assess degree of ataxia, acceptance of speculum, chewing on the speculum, headshaking, tongue movement, resistance to palpation, and eye appearance as related to the grimace score. During each examination, additional sedation of IV detomidine (0.006mg/kg) and butorphanol (0.006mg/kg) was administered at the discretion of the blinded practitioner to facilitate safe examination. At the second examination horses received the opposite treatment protocol and, following examination, a routine occlusal adjustment. Scores were compared using JMP software with a repeated measures mixed effects model, treatment as a fixed effect and horse and horse/treatment interaction as random effects. Significance was set at P<0.05. There were no significant differences in any of the single or overall sedation scores between treatment groups or within individual horses (P=0.3). Trends towards improvement of some assessed characteristics of sedation, including decreased tongue movement and less resistance to acceptance of speculum were observed. The use of midazolam may prove beneficial for routine oral examination, as well as other standing procedures, with no obvious undesired side effects.

Paradoxical Reaction to Hypnotics in Intensive Care Unit

Background

Paradoxical reactions (PR) to benzodiazepines are well-known, but PR can also follow sedation by propofol, although this has been reported only in the context of operating room anesthesia. We report a rare case of paradoxical excitement induced by midazolam and propofol.

Case presentation

A 78-year-old patient presented with multiorgan failure secondary to infectious pneumopathy. During intensive care unit (ICU) stay, he experienced 2 episodes of ventilator-acquired pneumonia and 1 of acute kidney failure requiring renal replacement therapy. Throughout the stay, he showed restlessness, uncontrollable muscle spasms and stiffness without any neurological focus. Paradoxical reaction to midazolam and to propofol was diagnosed; difficult withdrawal was followed by favorable progression.

Conclusion

PR in the ICU context is exceptional. The present case is unique, with severe PR not only to midazolam but also to propofol. This etiology, with difficult withdrawal, should be considered after ruling out all classical etiologies for refractory agitation.

Effect of butorphanol, midazolam or ketamine on romifidine based sedation in horses during standing cheek tooth removal

BACKGROUND

Standing surgery, especially dental procedures, are commonly performed in horses. This leads to an increasing demand for reliable sedation protocols. Therefore, it was the purpose of this study to investigate the influence of butorphanol, midazolam or ketamine on romifidine based sedation in horses during cheek tooth removal.

METHODS

Forty horses presented for tooth extraction were divided in four groups using matched pair randomization. Group R was sedated with romifidine (bolus 0.03 mg/kg, followed by a constant rate infusion (CRI) 0.05 mg/kg/h) and group RB with romifidine (same dose) and butorphanol (0.02 mg/kg; CRI 0.04 mg/kg/h). Group RM received romifidine (same dose) and midazolam (0.02 mg/kg; CRI 0.06 mg/kg/h) whereas group RK was administered romifidine (same dose) and ketamine (0.5 mg/kg; CRI 1.2 mg/kg/h). If sedation was not adequate a top up bolus of romifidine (0.01 mg/kg) was administered. The quality of sedation and the conditions for tooth extraction, the level of ataxia, chewing, head and tongue movement were evaluated by using a scoring system. The investigator was blinded to the applied sedation protocol. Furthermore, serum cortisol concentrations before, during and after the procedure were analyzed to gain more information about the stress level of the horses.

RESULTS

Horses in group RM showed significantly less chewing and tongue activity compared to horses sedated with romifidine alone or with butorphanol additionally, but also significantly higher levels of ataxia. The quality of sedation was significantly better if romifidine was administered in combination with ketamine compared to romifidine alone. Furthermore, horses of group RK needed less additional romifidine boli compared to all other groups. Blood cortisol concentrations during surgery in groups RB and RM remained unchanged. Horses of group R showed higher cortisol concentrations during sedation compared to horses of groups RB and RM.

CONCLUSION

Romifidine alone at an initial bolus dose of 0.03 mg/kg followed by a constant rate infusion of 0.05 mg/kg/h was insufficient to obtain an adequate level of sedation and led to increased stress levels, whereas the addition of butorphanol inhibited the stress response. The combination of romifidine with either midazolam or ketamine improved sedation quality and surgical conditions.

Benzodiazepines: Sedation and Agitation

Dental anxiety is common and frequently poses a barrier to necessary dental treatment. The increasing availability of conscious sedation in dental practice has made treatment much more accessible for anxious patients. At present, benzodiazepines are the most commonly used drugs in sedation practice and provide a pleasant experience for most, but not all, patients. An understanding of the mechanism of action of benzodiazepines should inform our practice and deepen our understanding of why and how sedation may fail. CPD/CLINICAL RELEVANCE: As an increasing number of dentists provide sedation for their patients an update on benzodiazepines is timely.

Usefulness of Ultrasound-Guided Lower Extremity Nerve Blockade in Surgery for Patellar Fracture

PURPOSE

To evaluate the usefulness of ultrasound-guided nerve blockade in patellar fracture surgery.

MATERIALS AND METHODS

Twenty-three patients who underwent metal fixation under ultrasound-guided lower extremity blockade after diagnosis of patellar fracture from July 2011 to June 2012 were enrolled in this study. Under ultrasound guidance, femoral nerve, lateral femoral cutaneous nerve, obturator nerve, and sciatic nerve blockades were performed. For evaluation of anesthesia, interference with overall surgery, such as intraoperative knee pain and tourniquet pain, was checked. Individual anesthetic complications, satisfaction with nerve blocks, and choice of future anesthesia method were investigated.

RESULTS

Nineteen patients underwent surgery without any pain and 4 patients with mild pain. Satisfaction was excellent in 17 patients, good in 5, and unsatisfactory in 1. No complications such as infection or nerve injury occurred. In terms of selection of future anesthesia, 22 patients chose a nerve blockade of the lower extremity under ultrasound guidance, and one chose general anesthesia.

CONCLUSIONS

Overall, ultrasound-guided nerve block of the lower extremity for patellar fracture surgery showed satisfactory results. Therefore, it could be a useful method to prevent complications associated with general or spinal anesthesia.

Successful flumazenil reversal of paradoxical reaction to midazolam in a child

BACKGROUND

Greater attention to and management of anxiety and pain in pediatric patients signifies a healthy evolution in the care of children in emergency departments (EDs). Interventions to address such distress may involve unanticipated adverse effects. Midazolam, a benzodiazepine commonly administered to children for anxiolysis, may precipitate paradoxical agitation and delirium, a rare but alarming effect that warrants prompt identification and treatment.

CASE REPORT

The case presented is that of a 4-year-old girl who received oral midazolam and developed a paradoxical reaction, which was reversed successfully with flumazenil. This is the first such case report in an ED involving a child. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians must stay abreast of the adverse and unintended effects of the treatments provided. The literature on benzodiazepine-induced paradoxical reactions is reviewed, and flumazenil as well as other treatment options and anxiolytic alternatives are presented.