Glycopyrrolate compared with atropine in association with ketamine anaesthesia

Effects of glycopyrrolate and atropine for oral secretions and perioperative hemodynamics in children undergoing tonsillectomy and adenoidectomy: a prospective, single-center, randomized, double-blind, controlled trial

Introduction

Glycopyrrolate is commonly researched as a preoperative medication or in conjunction with cholinesterase inhibitors to counteract the lingering muscarinic effects of non-depolarizing muscarinic agents. However, studies have yielded inconsistent results regarding the superiority of glycopyrrolate over other anti-cholinergic drugs, such as atropine, particularly its effect on heart rate, blood pressure (BP), and glandular secretions. This study aimed to evaluate the differences in perioperative oral secretions, hemodynamics, and recovery quality with glycopyrrolate versus those with atropine before anesthesia induction in children undergoing tonsillectomy and adenoidectomy.

Methods

In this prospective, single-center, randomized, double-blind, controlled trial, a total of 103 children were randomly assigned to group A (n = 51, glycopyrrolate 0.005 mg/kg) or B (n = 52, atropine 0.01 mg/kg). The follow-up anesthetic induction and maintenance protocols were the same in both groups. Vital signs, duration of surgery, extubation time, degree of wetness around the vocal cords during tracheal intubation, weight of oral secretions, and perioperative complications were recorded.

Results

No significant differences were observed in the degree of wetness around the vocal cords during tracheal intubation, as well as in the weight of oral secretions, duration of surgery, or extubation time, between the two groups. The intraoperative and postoperative heart rates were lower in group A than in group B (110.18 ± 10.58 vs. 114.94 ± 11.14, p = 0.028; 96.96 ± 10.81 vs. 103.38 ± 10.09, p = 0.002). The differences observed in the intraoperative and preoperative heart rates were lower in group A than in group B (23.84 ± 9.62 vs. 29.65 ± 8.75, p = 0.002). The differences observed in the postoperative and preoperative heart rates were lower in group A than in group B (10.63 ± 9.97 vs. 18.09 ± 9.39, p = 0.000).

Conclusion

Glycopyrrolate showed a smoother change in heart rate than atropine during and after tonsillectomy and adenoidectomy, with no effect on BP or recovery quality, and did not increase oral secretions. The findings indicate that glycopyrrolate can serve as an alternative to atropine to prevent secretions in anesthesia induction for tonsillectomy and adenoidectomy in children. Trial registration: This study was registered with the Chinese Clinical Trial Registry (Registration Number: ChiCTR2200063578; Date of Registration: 12/09/2022).

Glioblastoma: Current Status, Emerging Targets, and Recent Advances

Glioblastoma (GBM) is a highly malignant brain tumor characterized by a heterogeneous population of genetically unstable and highly infiltrative cells that are resistant to chemotherapy. Although substantial efforts have been invested in the field of anti-GBM drug discovery in the past decade, success has primarily been confined to the preclinical level, and clinical studies have often been hampered due to efficacy-, selectivity-, or physicochemical property-related issues. Thus, expansion of the list of molecular targets coupled with a pragmatic design of new small-molecule inhibitors with central nervous system (CNS)-penetrating ability is required to steer the wheels of anti-GBM drug discovery endeavors. This Perspective presents various aspects of drug discovery (challenges in GBM drug discovery and delivery, therapeutic targets, and agents under clinical investigation). The comprehensively covered sections include the recent medicinal chemistry campaigns embarked upon to validate the potential of numerous enzymes/proteins/receptors as therapeutic targets in GBM.

Comparison of Isoflurane, Ketamine-Dexmedetomidine, and Ketamine-Xylazine for General Anesthesia during Oral Procedures in Rice Rats (Oryzomys palustris)

Rice rats (Oryzomys palustris) are an unconventional laboratory species that has been used to study photoperiodicity, periodontitis, and osteonecrosis of the jaw. Interventional procedures that require anesthesia, including oral procedures, are sometimes necessary in preclinical settings. The use of anesthetics including isoflurane and ketamine combined with α2-adrenoreceptor agonists, such as dexmedetomidine and xylazine, is well-established for laboratory rodents. However, their effects have been studied only modestly in rice rats. The aims of this study were to 1) determine the safety and consistency of 3 common anesthetic modalities in rice rats; 2) compare the physiologic and clinical responses to these anesthetics, and 3) verify the effectiveness of the most successful modality by testing it during an oral procedure (tooth extraction). Isoflurane, intraperitoneal ketamine-dexmedetomidine, and intraperitoneal ketamine-xylazine were evaluated by using a crossover design, in which each rat received all of the anesthetics. Compared with ketamine-dexmedetomidine and ketamine-xylazine, isoflurane inhalation through a nose cone produced more rapid induction, entry to a surgical plane of anesthesia, and initial recovery. In addition, isoflurane produced optimal anesthesia throughout the procedure for most rats. Unlike ketamine-dexmedetomidine and ketamine-xylazine, isoflurane did not alter rectal temperature, SpO₂, or respiratory rate during the surgical tolerance period, whereas ketamine-dexmedetomidine and ketamine-xylazine decreased rectal temperature during the last stage of anesthesia and induced cardiorespiratory depression. Furthermore, 2 rats experienced negative outcomes warranting euthanasia: one after receiving ketamine-dexmedetomidine, and the other after ketamine-xylazine anesthesia. In conclusion, isoflurane was the most reliable and effective anesthetic in rice rats and maintained a surgical depth of anesthesia for as long as 30 min, thus supporting successful tooth extractions.

Ketamine-xylazine anaesthesia and orofacial administration of substance P: A lethal combination in rats

BACKGROUND AND AIMS

Ketamine+xylazine mixture is a widely used anaesthetic in animal experiments. In rats anaesthetized with this mixture, we have shown that injection of carrageenan, a standard proinflammatory stimulus, into the cheek (intra-oral injection) induced oedema. A likely mediator of this oedema is substance P (SP), a major transmitter of sensory nerves in orofacial tissue. We have assessed the effects of intra-oral injection of SP in rats.

EXPERIMENTAL APPROACH

SP (50-1μg per rat) was injected intra-orally in male adult Holtzman or Wistar rats, anaesthetized with ketamine+xylazine. For comparison, histamine (50μg) and 5-HT (5μg) were similarly injected. Antagonists of SP (SR140333, 2mg/kg), of histamine (pyrilamine, 2mg/kg) or of 5-HT (pizotifen, 2mg/kg) were subcutaneously (s.c.) injected, 30min before the corresponding agonist. Oedema in the cheek was assessed by measuring tissue thickness with calipers.

RESULTS

Intra-oral injection of SP (1-50μg per rat) in Holtzman or Wistar rats anaesthetized with ketamine+xylazine induced, dose-dependently, death within 15min, accompanied by signs of excessive salivation. Rats pretreated with SR140333 were protected against SP-induced lethality and the excessive salivation. However, intra-oral injection of either histamine or 5-HT did not induce death, only a characteristic cheek oedema. These doses of SP injected into the hindpaws of conscious Holtzman and Wistar rats only induced oedema with no deaths. In rats anaesthetized with inhaled isoflurane, intra-oral SP (50μg) induced only cheek oedema, with no deaths or excessive salivation. This oedema was prevented by pre-treating rats with SR140333, pyrilamine and pizotifen.

CONCLUSION

It is likely that the deaths were due to excessive salivation induced by the particular combination of ketamine and SP. Our results are presented as a warning to other experimenters who might use these two otherwise non-toxic conditions and the consequent unexpected and needless loss of experimental animals.

Clinical effects of adjunctive atropine during ketamine sedation in pediatric emergency patients

INTRODUCTION

The prophylactic coadministration of anticholinergics during dissociative sedation has been considered necessary to mitigate ketamine-associated hypersalivation. Given recent conflicting conclusions regarding adjunctive atropine, we compared the incidence of hypersalivation, degree of secretion, and related side effects with atropine or placebo as an adjunct to intravenous (IV) ketamine sedation for children.

METHODS

This controlled trial randomized children, 1 to 10 years old, requiring ketamine sedation in a tertiary emergency department to receive 0.01 mg/kg of atropine or placebo, along with IV ketamine (2 mg/kg). A nurse rated preprocedure and postprocedure salivation on a 100-mm visual analog scale and recorded the frequency and nature of airway complications and interventions for hypersalivation.

RESULTS

During 27 months, 140 patients were enrolled. Baseline characteristics did not differ between the 2 groups (P > .05). Secretion was significantly less in the atropine vs placebo group (mean visual analog scale score ± SD, 21.2 ± 13.1 [preprocedure] to 16.5 ± 9.9 [postprocedure] vs 22.4 ± 13.5 [preprocedure] to 27.0 ± 15.9 [postprocedure], respectively; P < .05). Visual analog scale scores greater than 50 were assigned to 7 (9.7%) of 72 and 1 (1.5%) of 68 patients in the placebo and atropine groups, respectively; these patients needed only medical procedures such as suction or airway repositioning. Heart rate was significantly higher in the atropine group compared with the placebo group (P < .05). There were no significant differences between the groups in terms of other adverse events.

CONCLUSION

Atropine as an adjunct to IV ketamine sedation in children significantly reduced hypersalivation, without providing a clinical benefit.

Anticholinergic medications for managing noisy respirations in adult hospice patients

PURPOSE

Anticholinergic medications for reducing noisy respirations in adult hospice patients are evaluated.

SUMMARY

Anticholinergic medications used to reduce noisy respirations from retained secretions in terminal patients include atropine, glycopyrrolate, scopolamine, and scopolamine derivatives. Pharmaceutical anticholinergic treatment of retained secretions in hospice patients was evaluated in six studies, three of which compared the efficacy of glycopyrrolate to scopolamine in actively dying patients. Subcutaneous glycopyrrolate, scopolamine hydrobromide, and scopolamine butylbromide were similar in their ability to reduce noisy respirations overall and lower and the level of distress exhibited by family members and visitors. Two of the six studies compared the efficacy of medication therapy after institutional formulary changes from scopolamine to glycopyrrolate. The same dosages of subcutaneous glycopyrrolate and scopolamine, which delivered an initial bolus followed by continuous infusion, were reported in each study. Both studies concluded that there was equivalent efficacy between the two products. One study reported a more rapid response in patients treated with glycopyrrolate. In comparison, the last study reported more rapid responses in patients who received scopolamine compared with patients who received glycopyrrolate. Retrospective reports described symptom improvement with parenteral scopolamine in most patients.

CONCLUSION

Parenteral and transdermal anticholinergic medications are useful for the reduction of noisy respirations in hospitalized hospice patients. Difficult administration makes oral and sublingual products less desirable for use in this population.

Effects of antitussive agents administered before bronchoalveolar lavage in horses

OBJECTIVE

To determine whether treatment of horses with antitussive agents before bronchoalveolar lavage (BAL) reduces the frequency and intensity of the cough reflex during BAL.

ANIMALS

8 healthy horses.

PROCEDURE

Standard BAL was performed on each horse weekly for 6 weeks. Detomidine was used as a general sedative, and various antitussive agents were evaluated for their suitability to suppress undesirable coughing. Treatments administered prior to BAL consisted of saline (0.9% NaCl) solution (control treatment), codeine, butorphanol tartrate, glycopyrrolate, lidocaine hydrochloride (final concentration, 0.33%), and lidocaine hydrochloride at a final concentration of 0.66% (lidocaine 0.66%). Frequency and intensity of coughing were digitally recorded throughout the BAL procedure. The volume of BAL fluid collected was measured, and the fluid was cytologically examined to assess potential effects of the medications on composition.

RESULTS

Coughing frequency was significantly reduced after intratracheal administration of lidocaine 0.66%. Moreover, intratracheal administration of lidocaine 0.66% or IV administration of butorphanol resulted in a significant reduction in the intensity of coughing episodes. All other treatments failed to significantly suppress coughing frequency and intensity, compared with results for the saline treatment. Glycopyrrolate caused obvious adverse clinical effects. Treatments did not influence the volume of BAL fluid collected nor composition of the fluid.

CONCLUSIONS AND CLINICAL RELEVANCE

Intratracheal administration of lidocaine (final concentration, 0.66%) proved to be the most reliable method to reduce frequency and intensity of coughing in horses during BAL.

Procedural Sedation and Analgesia in the Emergency Department: What Are the Risks?

The practitioner of emergency medicine is routinely faced with patients in need of emergent procedures and pain control and sedation. Our challenge is to make our patients' experiences as painless and as safe as possible, while maximizing our ability to perform the procedure at hand; this is not always an easy task given the propensity of each human body to react differently to interventions and stimuli. We can best meet this challenge by understanding how our patients and pharmaceutical agents intermingle in the risk-benefit equation we formulate before starting our "experiment." Coupling this information with fundamentally sound patient care and monitoring will minimize bad experiences with PSA for both the patient and practitioner.

Xerostomic complaints induced by an anti-sialogogue in healthy young vs. older adults

Complaints of xerostomia and salivary hypofunction are common in older adults. However, recent studies reported that dehydration-induced salivary hypofunction caused fewer xerostomic complaints in older compared with young adults. This may predispose older adults to developing oral problems that will subsequently not receive attention from health care providers. Since many medications are known to inhibit salivation, this study attempted to determine if an anticholinergic drug (glycopyrrolate) had a differential effect on xerostomic complaints in young vs. older adults. Eighteen young (age 20-38 yrs) and 18 older (age 60-77 yrs) healthy adults were given a 4.0 micrograms/kg dose of i.v. glycopyrrolate. For 6 hrs after drug administration, stimulated parotid salivary flow was collected, and an eight-item Visual Analogue Scale (VAS) subjective xerostomia test was given. At several time points post-i.v. glycopyrrolate, salivary flow rates were consistently lower in older compared with young adults. For some measures of xerostomic complaint (time to first complaint; time to maximum complaint; mean maximum complaint), there were no age-related differences for all VAS items. However, a trend for increased xerostomic complaints in older adults was demonstrated (time to recovery; total duration of complaint; number xerostomic at 6 hrs). These findings suggest that, given equal doses of an anti-sialogogue, salivary hypofunction is greater in healthy older adults, while increased complaints of xerostomia are not as consistent.

A double-blind comparison of low-dose intravenous ketamine and methohexital in adults

Two ultralight general anesthetic techniques, one using low-dose ketamine and the other using methohexital as the primary anesthetic agent, were compared for efficacy, safety, and psychomotor recovery in a double-blind fashion for use during third molar surgery. Low-dose intravenous ketamine as the primary anesthetic following premedication with fentanyl and midazolam, and in conjunction with nitrous oxide, appeared to produce less hypoxia, hypercarbia, and apnea than when methohexital was used. No significant differences were noted in heart rate or blood pressure between the techniques. The ketamine technique was universally preferred by the surgeons and anesthesiologists because of superior patient cooperation and airway management. No unpleasant psychomimetic side effects of significance were noted with the use of ketamine. Postoperative recovery took slightly longer in the ketamine group, with patients being judged fit for discharge approximately 10 to 15 minutes later than the patients who received methohexital.