Effect of remifentanil compared with fentanyl on intraocular pressure after succinylcholine and tracheal intubation

Changes in Intraocular Pressure following Narcosis With Medetomidine, Midazolam, and Fentanyl in Association With Initial Intraocular Pressure in Mice

PURPOSE

This article describes the development of decreased intraocular pressure (IOP) under general anesthesia with medetomidine, midazolam, and fentanyl in mice with normal and elevated IOP.

METHODS

IOP was measured using the iCare Tonolab rebound tonometer. Twelve 3-4 months-old male and female C57BL/6J mice were randomized to a control group with physiological IOP and a high IOP group with experimentally induced ocular hypertension using tarsal injections of dexamethasone-21-acetate. For anesthesia, medetomidine and midazolam were used, subgroups additionally received fentanyl. IOP was measured every 2.5 min for 30 min.

RESULTS

Control group differed with 14.89 mmHg (SEM: 0.58) significantly (p = 0.0002) from the high IOP group with initial 20.44 mmHg (SEM: 0.75). All groups showed a significant (p < 0.05) decrease in IOP under general anesthesia. There was no significant difference in IOP development and decrease between the group additionally receiving fentanyl and the group without fentanyl. The decrease in IOP was highly dependent on the initial value, with the high IOP group showing a greater decrease. After 10 min, no significant difference in IOP could be detected between the high IOP and control group.

CONCLUSIONS

In mice, general anesthesia with medetomidine and midazolam leads to a declining IOP over time. Adding fentanyl to the anesthesia did not alter these effects. The decline is time-dependent and IOP-dependent.

Effects of Short-Acting Opioids on Intraocular Pressure during General Anesthesia: Systematic Review and Network Meta-Analysis

Intraocular pressure (IOP) is crucial to the well-being of eyes. During anesthesia, the administration of succinylcholine and endotracheal intubation are associated with an increase in IOP, which may be attenuated by short-acting opioids. However, the drug of choice among the commonly used short-acting opioids is unclear. This study aimed to evaluate the effects of fentanyl, sufentanil, alfentanil, and remifentanil on IOP measured after the administration of succinylcholine and after endotracheal intubation in patients undergoing general anesthesia. Five databases were searched. Randomized controlled trials (RCTs) that compared short-acting opioids and reported at least one of the clinical outcomes of interest were included. Nine RCTs with 357 patients were included. Remifentanil (1 μg kg⁻¹) more effectively alleviated the increase in IOP than the placebo after the administration of succinylcholine [mean difference (MD) of IOP, −3.64; confidence interval (CI), −5.47 to −1.81 and after endotracheal intubation (MD, −9.71; CI, −11.91 to −7.51). Remifentanil (1 μg kg⁻¹) ranked the best in terms of both attenuating the increase in IOP after the administration of succinylcholine [surface under the cumulative ranking curve (SUCRA), 0.91; normalized entropy (NE), 0.47; and after endotracheal intubation (SUCRA, 0.89; NE, 0.54) among all of the treatments. Remifentanil (1 μg kg⁻¹) should be considered the drug of choice in the circumstances where increased IOP is a great concern.

Ocular complications of perioperative anesthesia: a review

Ocular complications associated with anesthesia in ocular and non-ocular surgeries are rare adverse events which may present with clinical presentations vacillating between easily treatable corneal abrasions to more serious complication such as irreversible bilateral vision loss. In this review, we outline the different techniques of anesthetic delivery in ocular surgeries and highlight the incidence and etiologies of associated injuries. The changes in vision in non-ocular surgeries are mistaken for residual sedation or anesthetics, therefore require high clinical suspicion on part of the treating ophthalmologists, to ensure early diagnosis, adequate and swift management especially in surgeries such as cardiac, spine, head and neck, and some orthopedic procedures, that have a comparatively higher incidence of ocular complications. In this article, we review the literature for reports on the clinical incidence of different ocular complications associated with anesthesia in non-ocular surgeries and outline the current understanding of pathophysiological processes associated with these adverse events.

The effects of remifentanil and esmolol on increase in intraocular pressure due to laryngoscopy and tracheal intubation: a double-blind, randomized clinical trial

PURPOSE

This study aimed to compare the effects of remifentanil and esmolol on the elevation of intraocular pressure (IOP) and hemodynamic response.

METHODS

After approval of the institutional Ethics Committee and obtaining informed consent, 60 adult patients with American Society of Anesthesiologists I-II status undergoing elective, nonophthalmic surgery were included in the study. Exclusion criteria were preexisting eye disease, neuromuscular disease, esophageal reflux, hiatus hernia, allergy to any of the study drugs, and the use of β-blockers, diuretics, or other antihypertensive agents. The patients were randomized into 2 groups by using the sealed-envelope method, as follows: group E (esmolol) and group R (remifentanil). A single intravenous dose of esmolol (0.5 mg/kg) or remifentanil (1 μg/kg) just before induction agents were given to patients in groups E and R, respectively. IOP, heart rate (HR), and mean arterial pressure (MAP) values were recorded before intubation and at 1, 3, 5, and 10 minutes after intubation.

RESULTS

The IOP decrease in group R was statistically significant compared with group E (P<0.01). HR values at 10 minutes after intubation were significantly decreased in group E compared with group R (P<0.05). There was no significant difference in MAP values between the groups.

CONCLUSIONS

It was concluded that remifentanil is more effective than esmolol in preventing IOP elevation related to laryngoscopy and tracheal intubation, while there is no significant difference between the 2 agents in terms of HR and MAP.

Comparison of the effects of remifentanil and alfentanil on intraocular pressure in cataract surgery

Background:

Anesthesia for ophthalmic surgery requires management of intraocular pressure (IOP) during perioperative period. In an open eye, in conditions such as after traumatic injury or during cataract surgery, IOP increase can lead to permanent vision loss. Administration of narcotics concomitant with anesthetics has the ability to reduce this increase of IOP. This clinical trial aims to compare the efficacy of remifentanil and alfentanil in preventing an increase in IOP after administration of succinylcholine, intubation and during anesthesia.

Methods:

This double-blind clinical trial was conducted on 50 patients undergoing elective general surgery for cataracts. Patients were randomly divided into two groups. Alfentanil (20 μg/kg in 30 s) for group 1 and remifentanil (1 μg/kg in 30 s) for group 2 were injected before induction of anesthesia, and 0.5 μg/kg/min alfentanil for group 1 and 0.1 μg/kg/min remifentanil for group 2 were infused during the anesthesia. Systolic and diastolic blood pressure, heart rate, and IOP from normal eye were measured before the induction, after administration of thiopental and succinylcholine, after tracheal intubation, and 2 min later, and were repeated in 2-min intervals until the end of operation.

Results:

IOP decreased after injection of anesthetics and remained lower all through the operation in both groups, but IOP decreased after injection of succinylcholine in remifentanil group while it increased in alfentanil group (P<0.05).

Conclusions:

Results of this study indicate benefits of both remifentanil and alfentanil in managing IOP after induction and during anesthesia. It seems that remifentanil is better than alfentanil in controlling the IOP after injection of succinylcholine.

Pharmacology of intravenous sedative/anesthetic medications used in oral surgery

This article provides an overview of historical and current sedative agents available to the dentist anesthetist. The surgeon is given rational choices for sedation and the individualization of drug selection for each patient. Total intravenous anesthesia is becoming increasingly popular for dental sedation because of the availability of ultra-short-acting drugs and computerized infusion technology. Levels of sedation are more easily achieved and maintained, and recovery is enhanced, which gives the operator extreme, moment-to-moment control of the anesthetic experience and improves patient outcomes.

Vitreous humour extrusion after suxamethonium induction of anaesthesia in a polytraumatized patient: a case report

Introduction. Suxamethonium, a deepolarizing muscle relaxant, increases intraocular pressure. It is therefore advised to be avoided in open globe surgery, for fear of extruding ocular contents. Several anecdotal reports support this fear. Some workers however, dispute this claim. There is as yet no formal case report in the literature on the subject. Case Presentation. A 34-year old Nigerian male, was involved in a road traffic accident. He presented at the Accident & Emergency Unit of our hospital about 2 hours after the accident. Clinical examination revealed right corneal laceration (with intact ocular contents) and intra-abdominal visceral injury. Emergency laparotomy was scheduled, to be followed with corneal repair. Anaesthesia was induced with 10 mg midazolam, 100 mg ketamine, and 100 mg suxamethonium given intravenously in sequence. After laparotomy, the ophthalmologists reported for the corneal repair, only to find that the vitreous humour has been extruded. Conclusion. The fear about the use of suxamethonium in open globe situations is real. It will be good clinical judgment to use alternative drugs and techniques to effect rapid muscle relaxation, in the anaesthetic management of the open globe patient. This would be of interest to anaesthetists, ophthalmologists and clinical pharmacologists among others.

Scandinavian clinical practice guidelines on general anaesthesia for emergency situations

Emergency patients need special considerations and the number and severity of complications from general anaesthesia can be higher than during scheduled procedures. Guidelines are therefore needed. The Clinical Practice Committee of the Scandinavian Society of Anaesthesiology and Intensive Care Medicine appointed a working group to develop guidelines based on literature searches to assess evidence, and a consensus meeting was held. Consensus opinion was used in the many topics where high-grade evidence was unavailable. The recommendations include the following: anaesthesia for emergency patients should be given by, or under very close supervision by, experienced anaesthesiologists. Problems with the airway and the circulation must be anticipated. The risk of aspiration must be judged for each patient. Pre-operative gastric emptying is rarely indicated. For pre-oxygenation, either tidal volume breathing for 3 min or eight deep breaths over 60 s and oxygen flow 10 l/min should be used. Pre-oxygenation in the obese patients should be performed in the head-up position. The use of cricoid pressure is not considered mandatory, but can be used on individual judgement. The hypnotic drug has a minor influence on intubation conditions, and should be chosen on other grounds. Ketamine should be considered in haemodynamically compromised patients. Opioids may be used to reduce the stress response following intubation. For optimal intubation conditions, succinylcholine 1-1.5 mg/kg is preferred. Outside the operation room, rapid sequence intubation is also considered the safest method. For all patients, precautions to avoid aspiration and other complications must also be considered at the end of anaesthesia.

Associations between intracranial pressure, intraocular pressure and mean arterial pressure in patients with traumatic and non-traumatic brain injuries

INTRODUCTION

Anatomical proximity of the eye and the intracranial space is a fact but the existence of physiological and pathophysiological relationships between them is elusive. The objective of this study was to explore anatomical and pathophysiological interactions between the eye and the intracranial space and to assess clinical utility of intraocular pressure measurement in estimation of intracranial pressure in patients with brain injuries and to discover how haemodynamic instability could influence these interactions. Controversy surrounds the recent literature concerning this problem and the consensus has not been achieved.

MATERIALS AND METHODS

We evaluated the correlation between intracranial pressure and intraocular pressure, intracranial pressure and mean arterial pressure, intraocular pressure and mean arterial pressure in 40 patients with brain injuries initially comatose, admitted to our hospital. All patients required the intracranial pressure monitoring on clinical grounds. Simultaneous recordings of intracranial pressure, intraocular pressure and mean arterial pressure were performed.

RESULTS

We calculated both the linear correlation coefficient and the Spearman rank-order correlation coefficient for all three relations. We found significant correlation between intraocular pressure and mean arterial pressure in 63% of the tested population. When the power of the test was increased, by considering only patients with 11 or more observations, this ratio increased to 76%. However, the correlation between intraocular pressure and intracranial pressure, as well as, between intracranial pressure and mean arterial pressure was not significant.

CONCLUSIONS

There is no anatomical and pathophysiological basis for the statement that intraocular pressure can be used as an indirect estimator of intracranial pressure.

Effect of oral gabapentin on the intraocular pressure and haemodynamic responses induced by tracheal intubation

BACKGROUND

Laryngoscopy and tracheal intubation may cause undesirable increases in blood pressure, heart rate (HR) and intraocular pressure (IOP). Gabapentin has been used effectively to attenuate the pressor response to laryngoscopy and tracheal intubation. We investigated whether the pre-treatment with gabapentin attenuates the IOP in addition to a haemodynamic response to tracheal intubation.

METHODS

Sixty ASA I-II patients were randomly allocated into two groups who received either gabapentin (800 mg) or placebo 2 h before surgery. IOP, mean arterial pressure (MAP) and HR were measured before and after the induction of anaesthesia as well as at 0, 1, 3, 5, 10 and 15 min following intubation.

RESULTS

IOP and MAP increased from baseline immediately after intubation in the placebo group (P=0.001 and 0.002, respectively). When compared with the placebo group, IOP values of the gabapentin group were significantly lower for the first 15 min after tracheal intubation (P=0.002 at 0 min, P=0.006 at 1 min, P<0.001 at 3 min, P<0.001 at 5 min, P<0.001 at 10 min and P=0.003 at 15 min) while MAP was lower in the first 10 min (P=0.001 at 0 min, P=0.002 at 1 min, P<0.001 at 3 min, P<0.001 at 5 min and P=0.028 at 10 min). These results showed that gabapentin effectively suppresses the increase in IOP secondary to endotracheal intubation and attenuates the increases in MAP.

CONCLUSION

It is suggested that gabapentin is a useful adjuvant in order to prevent an increase in the IOP in response to laryngoscopy and tracheal intubation.

Anesthetic management of preschool children with penetrating eye injuries: postal survey of pediatric anesthetists and review of the available evidence

BACKGROUND

Pediatric anesthetists were surveyed regarding their anesthesia management of a screaming child with a penetrating eye injury. The results are reviewed in relation to the available evidence in the literature.

METHODS

A postal survey was sent to all the members of the APA living in the UK. Seven clinical questions were asked regarding the management of penetrating eye injury and two questions regarding seniority and the number of cases seen.

RESULTS

Of the 318 questionnaires sent out 238 were evaluated. Of the responders indicating the number of cases seen, 21.2% had never seen a single case, 55.1% had seen <5, 17.8% had seen 5-10, and 5.9% had seen >10 cases. Suxamethonium was used more often by respondents who had handled more cases; 42.9% of those doing >10 compared with 10% of those doing less than five cases. Senior anesthetists preferred the use of techniques without relaxants and to extubate children under deep anesthesia.

CONCLUSIONS

Few people have extensive experience managing a penetrating eye injury in a child. A variety of anesthesia techniques are used for induction with anesthetists avoiding suxamethonium, despite there being little evidence in the literature that the use of suxamethonium is harmful to the open globe.

Remifentanil

Remifentanil (Ultiva), a fentanyl derivative, is an ultra-short acting, nonspecific esterase-metabolised, selective mu-opioid receptor agonist, with a pharmacodynamic profile typical of opioid analgesic agents. Notably, the esterase linkage in remifentanil results in a unique and favourable pharmacokinetic profile for this class of agent. Adjunctive intravenous remifentanil during general anaesthesia is an effective and generally well tolerated opioid analgesic in a broad spectrum of patients, including adults and paediatric patients, undergoing several types of surgical procedures in both the inpatient and outpatient setting. Remifentanil is efficacious in combination with intravenous or volatile hypnotic agents, with these regimens generally being at least as effective as fentanyl- or alfentanil-containing regimens in terms of attenuation of haemodynamic, autonomic and somatic intraoperative responses, and postoperative recovery parameters. The rapid offset of action and short context-sensitive half-time of remifentanil, irrespective of the duration of the infusion, makes the drug a valuable opioid analgesic option for use during balanced general inhalational or total intravenous anaesthesia (TIVA) where rapid, titratable, intense analgesia of variable duration, and a fast and predictable recovery are required.

Target concentrations of remifentanil with propofol to blunt coughing during intubation, cuff inflation, and tracheal suctioning

BACKGROUND

The target blood concentrations of propofol and remifentanil, when used in combination, required to blunt the cough response to tracheal intubation, cuff inflation, and tracheal suctioning without neuromuscular blocking agents are not known.

METHODS

In a randomized prospective study, 81 patients were enrolled to determine which of three target remifentanil blood concentrations was required to blunt coughing during intubation, cuff inflation, and tracheal suctioning. Anaesthesia was achieved with propofol at a steady effect-site concentration of 3.5 microg ml(-1). The target blood remifentanil concentrations were 5, 10, or 15 ng ml(-1). These concentrations were maintained for 12 min before intubation.

RESULTS

There was no cough response to intubation in more than 74% of patients and no significant difference in the incidence of coughing with intubation between the three groups. Significant difference in coughing, diminishing with increasing remifentanil target concentration, was observed with cuff inflation (P=0.04) and tracheal suctioning (P=0.007). Bradycardia and hypotension was more frequent with the remifentanil target concentration of 15 ng ml(-1). Tracheal suctioning resulted in more coughing than intubation (P=0.01) or cuff inflation (P=0.004).

CONCLUSION

Target remifentanil blood concentrations of 5, 10, and 15 ng ml(-1) associated with a 3.5 microg ml(-1) propofol target blood concentration provided good intubating conditions and absence of cough about 75% of the time. Higher target remifentanil concentrations were associated with less coughing during tracheal tube cuff inflation and tracheal suctioning.