Lateralized Raise in Intraocular Pressure During Electroconvulsive Therapy: A Tonometry Pilot Study

Right unilateral ECT causes an increase in eye pressure that is partially lateralized, higher on the right side.

Objective

The aim of this study was to evaluate intraocular pressure (IOP) changes during and after electroconvulsive therapy.

Methods

In 20 patients, IOP was measured using a handheld iCare tonometer before, during, and up to 15 minutes after the seizure. Electrode placement was either right unilateral (RUL) or bilateral (BL). Statistical analyses were done at baseline, during, and 15 minutes after the seizure.

Results

In the RUL group (n = 14), the IOP in the left eye increased from 14.8 mm Hg before the seizure to 27.8 mm Hg during the seizure (P = 0.0001) and decreased to 14.0 mm Hg after the seizure (P = 0.0002). The IOP in the right eye increased from 15.4 mm Hg before the seizure to 34.4 mm Hg during the seizure (P = 0.0001) and decreased to 16.0 mm Hg after the seizure (P = 0.0002).

In the BL group (n = 6), the IOP in the left eye increased from 13.0 mm Hg before the seizure to 26.3 mm Hg during the seizure (P = 0.1250) and decreased to 14.5 mm Hg after the seizure (P = 0.250). In the right eye, the IOP increased from 13.3 mm Hg before the seizure to 28.4 mm Hg during the seizure (P = 0.1250) and decreased to 13.7 mm Hg after the seizure (P = 0.25).

When the results were compared between the 2 electrode placements, the difference in IOP between the right and left eye was higher in the RUL group during (RUL 6.7 mm Hg vs BL 2.0 mm Hg, P = 0.0231) and after (RUL 2.1 mm Hg vs BL −0.8 mm Hg, P = 0.0492) the seizure.

Conclusions

RUL stimulation with electroconvulsive therapy causes a rise in IOP that is partially lateralized, ipsilateral to the side of stimulation.

Perioperative Care of the Patient with Eye Pathologies Undergoing Nonocular Surgery

The authors reviewed perioperative ocular complications and implications of ocular diseases during nonocular surgeries. Exposure keratopathy, the most common perioperative eye injury, is preventable. Ischemic optic neuropathy, the leading cause of perioperative blindness, has well-defined risk factors. The incidence of ischemic optic neuropathy after spine fusion, but not cardiac surgery, has been decreasing. Central retinal artery occlusion during spine fusion surgery can be prevented by protecting eyes from compression. Perioperative acute angle closure glaucoma is a vision-threatening emergency that can be successfully treated by rapid reduction of elevated intraocular pressure. Differential diagnoses of visual dysfunction in the perioperative period and treatments are detailed. Although glaucoma is increasingly prevalent and often questions arise concerning perioperative anesthetic management, evidence-based recommendations to guide safe anesthesia care in patients with glaucoma are currently lacking. Patients with low vision present challenges to the anesthesia provider that are becoming more common as the population ages.

Analysis of Microvasculature in Nonhuman Primate Macula With Acute Elevated Intraocular Pressure Using Optical Coherence Tomography Angiography

Purpose

To investigate responses of macular capillary vessel area density (VAD) of superficial and deep retinal vascular plexuses to elevations in intraocular pressure (IOP) in cynomolgus macaque monkeys using optical coherence tomography angiography (OCTA).

Methods

In five general anesthetized male cynomolgus monkeys, the IOP was increased incrementally by 10 mmHg from baseline (10 mmHg) to 70 mmHg and then decreased back to 10 mmHg (recovery state). Structural OCT (30° × 30°) and OCTA (20° × 15°) centered on the macula were obtained at each IOP and 3, 15, and 30 minutes after recovery. En face images of the superficial vascular complex (SVC) and deep vascular complex (DVC) were extracted, and VAD (%) compared with that at baseline was calculated.

Results

The VADs in the SVC and DVC at baseline and at 30 mmHg IOP were 34.96%, 34.15%, 35.38%, and 30.12%, respectively. The VAD plateaued until 30 mmHg; however, the VAD was affected more in the DVC than in the SVC (P = 0.008) at 30 mmHg. It showed a significant reduction at 40 mmHg (16.52% SVC, P = 0.006; 18.59% DVC, P = 0.012). In the recovery state, the SVC showed full retention of baseline VAD, but the DVC maintained VAD approximately 70% of that at baseline. Structural OCT showed hyperreflectivity in the nuclear layer, retinal swelling, and an undifferentiated ellipsoid zone from 50 mmHg.

Conclusions

Despite physiological autoregulation, perifoveal microcirculation was affected at high IOP ≥ 40 mmHg, especially in the DVC, which explains the pathological mechanism of macular vulnerability in ischemic diseases.

Attenuation of increased intraocular pressure with propofol anesthesia: A systematic review with meta-analysis and trial sequential analysis

Attenuation of an increase in intraocular pressure (IOP) is crucial to preventing devastating postoperative visual loss following surgery. IOP is affected by several factors, including the physiologic alteration due to pneumoperitoneum and patient positioning and differences in anesthetic regimens. This study aimed to investigate the effects of propofol-based total intravenous anesthesia (TIVA) and volatile anesthesia on IOP. We searched multiple databases for relevant studies published before October 2019. Randomized controlled trials comparing the effects of propofol-based TIVA and volatile anesthesia on IOP during surgery were considered eligible for inclusion. Twenty studies comprising 980 patients were included. The mean IOP was significantly lower in the propofol-based TIVA group after intubation, pneumoperitoneum, Trendelenburg positioning, and lateral decubitus positioning. Moreover, mean arterial pressure and peak inspiratory pressure were also lower after intubation in the propofol-based TIVA group. Trial sequential analyses for these outcomes were conclusive. Propofol-based TIVA is more effective than volatile anesthesia during surgery at attenuating the elevation of IOP and should be considered, especially in at-risk patients.

Effects of intubation with a double-lumen endotracheal tube on intraocular pressure during rapid sequence induction using succinylcholine chloride in patients with or without underlying systemic hypertension

Background

Tracheal intubation is closely associated with increases in intraocular pressure (IOP); however, the effects of double-lumen tube (DLT) intubation on IOP have not been validated. Systemic hypertension (HTN) is another factor that may increase IOP. In this study, we observed differences in IOP increases between DLT and singlelumen tube (SLT) intubation, and evaluated the influence of underlying HTN during rapid sequence induction.

Methods

Sixty-eight patients were allocated into one of the following group: SLT/without HTN (n = 17), SLT/HTN (n = 17), DLT/without HTN (n = 17), and DLT/HTN (n = 17). An SLT was inserted for orthopedic or gynecological surgery, and a DLT was inserted for lung surgery after rapid sequence induction using succinylcholine. IOP was measured before anesthetic induction and until 10 min after intubation using a handheld tonometer (Tono-Pen AVIA^®).

Results

In the DLT/without HTN and DLT/HTN groups, the maximum increases in IOPs after tracheal intubation were 7.9 and 12.2 mmHg, respectively, compared to baseline. In the SLT/without HTN and SLT/HTN groups, the maximum increases were 5.0 and 4.9 mmHg, respectively, compared to baseline. In comparisons between patients with and without underlying HTN, the values of IOPs were comparable.

Conclusions

Tracheal intubation with a DLT is associated with more increases in IOPs than with an SLT in rapid sequence induction. Well-controlled underlying hypertension did not increase IOP during tracheal intubation.

Intraocular pressure during neurosurgical procedures in context of head position and loss of cerebrospinal fluid

OBJECTIVE

Perioperative visual loss (POVL) is a rare but serious complication in surgical disciplines, especially in spine surgery. The exact pathophysiology of POVL remains unclear, but elevated intraocular pressure (IOP) is known to be part of it. As POVL is rarely described in patients undergoing intracranial or intradural surgery, the aim of this study was to investigate the course of IOP during neurosurgical procedures with opening of the dura mater and loss of CSF.

METHODS

In this prospective, controlled trial, 64 patients fell into one of 4 groups of 16 patients each. Group A included patients undergoing spine surgery in the prone position, group B patients had intracranial procedures in the prone position, and group C patients were treated for intracranial pathologies in a modified lateral position with the head rotated. In groups A-C, the dura was opened during surgery. Group D patients underwent spine surgeries in the prone position with an intact dura. IOP was measured continuously pre-, peri-, and postoperatively.

RESULTS

In all groups, IOP decreased after induction of anesthesia and increased time dependently after final positioning for the operation. The maximum IOP in group A prior to opening of the dura was 28.6 ± 6.2 mm Hg and decreased to 23.44 ± 4.9 mm Hg directly after dura opening (p < 0.0007). This effect lasted for 30 minutes (23.5 ± 5.6 mm Hg, p = 0.0028); after 60 minutes IOP slowly increased again (24.5 ± 6.3 mm Hg, p = 0.15). In group B, the last measured IOP before CSF loss was 28.1 ± 5.0 mm Hg and decreased to 23.5 ± 6.1 mm Hg (p = 0.0039) after dura opening. A significant IOP decrease in group B lasted at 30 minutes (23.6 ± 6.0 mm Hg, p = 0.0039) and 60 minutes (23.7 ± 6.0 mm Hg, p = 0.0189). In group C, only the lower eye showed a decrease in IOP up to 60 minutes after loss of CSF (opening of dura, p = 0.0007; 30 minutes, p = 0.0477; 60 minutes, p = 0.0243). In group D (control group), IOP remained stable throughout the operation after the patient was prone.

CONCLUSIONS

This study is the first to demonstrate that opening of the dura with loss of CSF during neurosurgical procedures results in a decrease in IOP. This might explain why POVL predominantly occurs in spinal but rarely in intracranial procedures, offers new insight to the pathophysiology of POVL, and provides the basis for further research and treatment of POVL.German Clinical Trials Register (DRKS) no.: DRKS00007590 (drks.de).

Agreement profiles for rebound and applanation tonometry in normal and glaucomatous children

Objectives:

To investigate agreement between intraocular pressure measurements by the rebound tonometer and handheld Perkins applanation tonometer in children with and without primary congenital glaucoma and test agreement with intraocular pressure and age variations.

Materials and methods:

A prospective non-interventional comparative study done on 223 eyes of 115 children, 161 normal eyes, and 62 eyes with primary congenital glaucoma. Intraocular pressure measurements were obtained in the upright position by rebound tonometer first, followed by installation of topical anesthetic eye drops (benoxinate), then measured by Perkins applanation tonometer.

Results:

For all eyes, mean difference between Perkins applanation tonometer and rebound tonometer was −0.59 ± 2.59 mmHg, p = 0.001. Regression analysis with (r) = 0.9, (r2) = 0.79, and p < 0.001. In primary congenital glaucoma: there was a mean difference of −.79 ± 2.82 (p = 0.032), a good correlation with (r) = 0.94, (r2) = 0.87%, and 95% level of agreement: –6.34 to +4.76. In normal eyes: mean difference was −.52 ± 2.5 (p = 0.01), correlation: (r) = 0.8, (r2) = 0.64, and p = 0.001. The 95% level of agreement −5.41 and +4.36 mmHg. In intraocular pressure ⩽ 15 mmHg: mean difference −0.89 ± 2.15 mmHg, 95% level of agreement between −5.1 and +3.32 mmHg, p < 0.001. In intraocular pressure >15 mmHg: mean difference was 0.04 ± 3.28 mmHg, 95% level of agreement −6.38 and +6.46 mmHg, p = 0.914.

Conclusion:

There is a good correlation between rebound tonometer and Perkins applanation tonometer in children with and without primary congenital glaucoma; however, rebound tonometer overestimates the intraocular pressure, and in intraocular pressure >15 mmHg there is less agreement between the two devices. Hence, in higher intraocular pressure measurement caution should be taken when interpreting rebound tonometer readings, and a confirmatory measurement using Perkins applanation tonometer is advised.

Are you seeing this: the impact of steep Trendelenburg position during robot-assisted laparoscopic radical prostatectomy on intraocular pressure: a brief review of the literature

With the increasing popularity, frequency, and acceptance of the robotic-assisted laparoscopic radical prostatectomy procedure, an awareness of unique intra- and postoperative complications is heightened, including that of increases in intraocular pressure. The steep Trendelenburg positioning required for operative exposure has been shown to increase this value. While the literature is infrequent and undeveloped, certain anesthetic parameters including deep neuromuscular blockade, modified positioning, and the use of dexmedetomidine have been shown to have mild-to-modest decreases in intraocular pressure for baseline. In the four randomized control trials and four observational studies that were found via PubMed/Medline search, the aforementioned techniques demonstrate some preliminary evidence of operative considerations in this unique patient population. These modifications may prove to have even greater significance in patients with pre-existing ophthalmologic pathologies, such as glaucoma, which were excluded from the studies' analyses. This review summarizes the early literature obtained in this subject, with the intent of emphasizing the initial hypotheses and identifying areas for future study.

Bilateral corneal denting after surgery under general anesthesia: A case report

Purpose

To report a case of temporary bilateral corneal denting in a patient who underwent cardiovascular surgery under general anesthesia.

Observations

A 71-year-old male with no history of ophthalmological disease experienced bilateral corneal denting immediately after undergoing surgery for aneurysm of the thoracic aorta under general anesthesia. Anesthesia was induced with propofol and maintained with rocuronium bromide and remifentanil hydrochloride. The initial examination revealed significant denting on the surface of both the corneas and ocular hypotension. Visual evaluation could not be performed due to the patient's low level of consciousness resulting from delayed emergence from anesthesia. After applying tropicamide and phenylephrine ophthalmic solution for fundus examination, the ocular morphology improved. Ocular pressure was normal on the day after surgery, and creasing on the surface of the corneas had disappeared.

Conclusions

and Importance: We experienced a patient with bilateral corneal denting following a cardiovascular surgery under general anesthesia. The dents could be attributed to augmentation of ocular hypotension using several types of anesthesia at relatively high doses.

Sub-Tenon's anesthesia for canine cataract surgery

OBJECTIVE

To test a sub-Tenon's anesthesia technique in dogs as an alternative to systemic neuromuscular blockade to aid in canine cataract surgery under general anesthesia.

PROCEDURES

A prospective controlled clinical study was performed involving 12 dogs undergoing bilateral cataract surgery under general anesthesia. One eye was randomly assigned to have phacoemulsification and prosthetic lens implantation performed with sub-Tenon's anesthesia (STA), and the control eye had surgery performed with systemic neuromuscular blockade (NMB). Intraocular pressure (IOP) was measured immediately before and after STA administration. Globe position, globe rotation, pupillary dilation, and vitreal expansion were assessed for both STA and NMB eyes during surgery.

RESULTS

Sub-Tenon's anesthesia produced a globe position suitable for cataract surgery with the degree of vitreal expansion not significantly different to control NMB eyes. STA produced greater anterior globe displacement than NMB in all cases. STA had no significant effect on IOP.

CONCLUSION

Sub-Tenon's anesthesia was an effective alternative to systemic neuromuscular blockade for canine cataract surgery and may be beneficial for surgical exposure in deep orbited breeds.

Effect of Continuous Systemic Administration of Esmolol on Intraocular Pressure During Surgery in a Sustained Steep Trendelenburg Position

PURPOSE

To investigate the effects of continuous systemic administration of esmolol on intraocular pressure (IOP) during laparoscopic and robotic surgeries for recto-sigmoid cancer in a steep Trendelenburg position.

MATERIALS AND METHODS

A total of 50 patients undergoing laparoscopic surgery in a steep Trendelenburg position were included. Patients in the esmolol (E) group received a 0.25 mg/kg IV loading dose of esmolol before anesthesia, followed by an infusion of 15 μg/kg/min throughout the operation. Patients in the saline (S) group were infused with the same volume of normal saline. IOP and ocular perfusion pressure were measured 16 times: before anesthetic induction (T1), before administration of the study drug (T2), after administration of anesthetic induction agents (T3), after tracheal intubation (T4), 1, 3, 5, and 10 minutes after tracheal intubation (T5-T8), immediately after intraperitoneal CO2 insufflation (T9), immediately after the steep Trendelenburg position (T10), 1, 2, and 4 hours after the steep Trendelenburg position (T11-T13), just before the supine position (T14), and 10 and 30 minutes after the supine position (T15, T16).

RESULTS

The IOP increased markedly after adopting the steep Trendelenburg position, reaching 28.8±4.4 mm Hg in group S. The IOP at T13 in group S was ∼5.7 mm Hg higher than in group E. The IOP at T13 was ∼10.6 mm Hg higher than in T1 in group S, but only ∼4.4 mm Hg higher than in group E.

CONCLUSIONS

Continuous systemic administration of esmolol can alleviate the increase in IOP during a sustained steep Trendelenburg position without adverse cardiovascular effects.

Do Intraocular Pressure Measurements Under Anesthesia Reflect the Awake Condition?

BACKGROUND

Anesthesia or sedation is needed when intraocular pressure (IOP) measurement is required in certain circumstances. The effect of different anesthetic regimens on the IOP is still debatable. We aimed to evaluate alterations in the IOP under anesthesia with either propofol or different end-tidal concentrations of sevoflurane, when compared with the awake state.

METHODS

The IOP was measured in both eyes of 20 adult patients undergoing extraocular ophthalmic surgeries at 5 timepoints: before the induction of general anesthesia (under topical anesthesia), after the induction using propofol target-controlled infusion, and under 3 end-tidal concentrations of sevoflurane (0.5%, 2%, and 5%), either in a decreasing (group A) or an increasing (group B) concentration order.

RESULTS

With either propofol or sevoflurane anesthesia, the IOP did not differ significantly from the measurement performed during the awake state (no anesthesia), regardless of the concentration of sevoflurane used (in the range of 0.5% to 5%) or the order of sevoflurane administration (from low to high concentration or vice versa).

CONCLUSIONS

These data suggest that propofol and sevoflurane are valid anesthetic agents for the evaluation of IOP in adults when anesthesia is needed.

How does sevoflurane induction, followed by a ketamine maintenance infusion, affect intraocular pressure? Establishment of an anaesthetic protocol for paediatric glaucoma examinations under anaesthesia

Accurate measurement of intraocular pressure (IOP) is essential in paediatric glaucoma management. Children require serial measurements and examination under anaesthesia (EUA). Most anaesthetic agents reduce IOP, and the ideal time to measure IOP under anaesthesia is questionable.

STUDY PURPOSE

To determine the effect of sevoflurane induction, followed by intravenous ketamine infusion on IOP, in children undergoing EUA for glaucoma or suspected glaucoma, and to establish the earliest time point at which reliable, repeatable IOP measurements can be obtained under anaesthesia.

METHOD

A prospective, descriptive study of IOP changes occurring in children requiring EUAs. A standardised anaesthetic protocol: sevoflurane induction, intravenous cannulation, 2 mg/kg intravenous ketamine bolus and 4 mg/kg/hour maintenance for 15 min. IOP measurements (taken supine with a Perkins applanation tonometer) and physiological variables were recorded.

RESULTS

IOPs were measured in 25 children (50 eyes). Twenty-six eyes (52%) were glaucomatous. Mean patient age was 29 months (2-88 months). Physiological variables returned to baseline at 8 min, correlating with recorded sevoflurane elimination. Mean IOP after sevoflurane induction was 3.68 mm Hg lower than with ketamine maintenance at 15 min (95% CI 1.35 to 6.02 mm Hg) (p=0.002). Contrastingly, the difference in IOP between ketamine anaesthesia at 15 min and near wakefulness was 0.28 mm Hg (95% CI -2.23 to 2.79 mm Hg) (p=0.826).

CONCLUSION

Sevoflurane's IOP-lowering effect is reversed 15 min after the discontinuation of the inhalational gas, if anaesthesia is maintained with an intravenous ketamine infusion. IOP measurements appear to stabilise at this time point until the point of near wakefulness and may reflect awake values.

Does general anesthesia have a clinical impact on intraocular pressure in children?

BACKGROUND

Reliable measurement of intraocular pressure (IOP) is crucial in pediatric patients with suspected glaucoma. General anesthesia (GA) is usually needed in infants to allow a thorough examination. However, anesthesia itself may influence IOP, depending on the type used and the depth of sedation. The purpose of this study was to evaluate the normal distribution of IOP during GA in healthy children and to analyze differences in IOP relative to the anesthetics used and the measurement time point.

METHODS

Approval for this observational study was received from the local institutional review boards and written informed consent was obtained from the children's parents. A total of 100 pediatric patients with no history of glaucoma scheduled for nonintraocular surgery underwent general anesthesia, induced with sevoflurane (s) or propofol (p) and maintained with either sevoflurane with remifentanil (S) or propofol with remifentanil (P). The patients were grouped to one of four subgroups (sS, sP, pP, pS) depending on the anesthetics used during induction and maintenance. Hemodynamic parameters and IOP were measured in both eyes at four defined time points: before anesthesia induction (M1); in apnea immediately after induction and before insertion of a laryngeal mask airway (M2); in deep anesthesia during mechanical ventilation (M3); and after extubation (M4), using a handheld Perkins applanation tonometer. Differences in IOP in both eyes during the measurement periods were analyzed using multivariate repeated-measures analysis of variance and Tukey-HSD as a posthoc test with statistical significance set at P < 0.05. Pearson correlation coefficient was used to investigate further relationships between heart rate, systolic blood pressure, and IOP.

RESULTS

General anesthesia reduced IOP significantly. The mean IOP was normally distributed, with a mean of 7.4 ± 2.89 mmHg at M1. It decreased significantly to a minimum of 5.6 ± 3.04 mmHg (P < 0.01) at M2 and increased significantly to 7.2 ± 2.51 mmHg (P < 0.01) at M3 and again to 8.4 ± 3.72 mmHg (P = 0.03) at M4. All four subgroups (sS, sP, pP, pS) showed comparable decreases in IOP between M1 and M2. During deep anesthesia (M3) and during reversal (M4), the IOP increased again in all groups. During reversal (M4), however, the sS group had a significantly lower IOP than the pP group (P = 0.001) and sP group (P = 0.02). There were no correlations between changes in IOP and gender, age, or type of surgery.

CONCLUSIONS

Sevoflurane and propofol, both in combination with remifentanil, significantly lower IOP in children. Individual IOP levels rise and fall during anesthesia, depending on the time point of measurement. The lowest IOP can be measured immediately after induction of anesthesia. This needs to be taken into account when measuring IOP in children.

Changes in intraocular pressure during surgery in the lateral decubitus position under sevoflurane and propofol anesthesia

Intraocular pressure (IOP) has been shown to change with body position. Several studies have shown that the lateral decubitus position (LDP) is associated with a significant increase in IOP in the dependent eye. However, whether anesthetic agents alter IOP in the LDP remains unclear. This study investigated the effect of sevoflurane and propofol anesthesia on IOP in the LDP. A total of 28 patients undergoing surgery in the LDP were included. Patients were randomly allocated to sevoflurane or propofol groups. IOP in both eyes was recorded and compared between groups at five time points: after anesthesia induction, after endotracheal intubation, at 5 min and 1 h after a positional change to the LDP, and 5 min after returning to the supine position. In the sevoflurane group, IOP was significantly increased in both dependent and non-dependent eyes 1 h after changing to the LDP. In the propofol group, IOP decreased in both dependent and non-dependent eyes after tracheal intubation, but did not increase after changing to the LDP. The number of patients in whom IOP increased to ≥28 mmHg was greater in the sevoflurane group than in the propofol group. Propofol may be better than sevoflurane for the maintenance of anesthesia in the LDP. Monitoring of IOP in the LDP might help avoid ophthalmic complications.

Ocular Complications in Laparoscopic Surgery: Review of Existing Literature and Possible Prevention and Treatment

During laparoscopic surgery, ocular complications are possible, sometimes leading to devastating visual losses, hardly susceptible to recovery, although rare. Principal ocular adverse events are represented by corneal abrasions and the perioperative visual loss (POVL). POVL onset is related to intraocular pressure elevations (particularly after patient positioning in Trendelenburg or prone decubitus, depending on the surgical procedure), anesthesiologic factors and patients' characteristics. In the light of evidence from the existing literature, the authors suggest surgical and anesthesiologic measures to prevent and manage ocular complications in laparoscopic surgery. Apart from general recommendations, this article indicates practical guidelines specific for robot-assisted laparoscopic interventions and spinal surgery, as well as laparoscopic colorectal resection, radical prostatectomy, and gynecologic surgery. In conclusion, in order to better manage these complications, it is advisable to develop an interdisciplinary collaboration between surgeons, anesthesiologists, and ophthalmologists, on a procedural and medico-legal level, with the intent of mutual training.

Total intravenous anesthesia will supercede inhalational anesthesia in pediatric anesthetic practice

Inhalational anesthesia has dominated the practice of pediatric anesthesia. However, as the introduction of agents such as propofol, short-acting opioids, midazolam, and dexmedetomidine a monumental change has occurred. With increasing use, the overwhelming advantages of total intravenous anesthesia (TIVA) have emerged and driven change in practice. These advantages, outlined in this review, will justify why TIVA will supercede inhalational anesthesia in future pediatric anesthetic practice.

The effect of I-gel ™ airway on intraocular pressure in pediatric patients who received sevoflurane or desflurane during strabismus surgery

OBJECTIVES

The aim of this study was to investigate the effect of I-gel(TM) laryngeal mask airway on intraocular pressure (IOP) in children with strabismus undergoing balanced anesthesia with sevoflurane or desflurane.

METHODS

Forty-seven children, ASA physical status I, were scheduled for elective strabismus surgery. Patients were randomly assigned to one of the two inhalation anesthetic groups. Sevoflurane group comprised of 27 children, and desflurane group comprised of 20 children. Anesthesia was induced and maintained with sevoflurane or desflurane. No muscle relaxant was used. IOPs were measured before anesthesia, at 2 and 5 min after insertion of I-gel(TM) and after removal of I-gel(TM) . IOP measurements were obtained by Tonopen(®).

RESULTS

Intraocular pressure significantly decreased 2 min after insertion of I-gel(TM) in both sevoflurane and desflurane groups (P < 0.001). Measurements 5 min after I-gel(TM) insertion were also significantly lower than those of before insertion in both groups (P < 0.01). However, no significant differences were found between the preoperative measurement and the measurement after removal of I-gel(TM) within two groups (P = 0.072 and P = 0.547, respectively). No significant differences were found in all IOP measurements between sevoflurane and desflurane groups.

CONCLUSION

Insertion of I-gel(TM) laryngeal mask airway with giving sevoflurane or desflurane inhalation anesthetics seemed not to cause any increase in IOPs in pediatric ophthalmic surgery.

Effect of general anesthetics on IOP in elevated IOP mouse model

Elevated intraocular pressure (IOP) is the best recognized risk factor for the pathogenesis of glaucoma and the extent of retinal ganglion cell (RGC) degeneration in glaucoma is closely correlated with the extent of IOP elevation. Therefore, accurately and reliably measuring IOP is critical in investigating the mechanism of pressure-induced RGC damage in glaucoma. However, IOP is measured under general anesthesia in most studies using mouse models and many anesthetics affect the IOP measurements in both human and animals. In the present study, we used a noninvasive approach to measure the IOP of mice with normal and elevated IOP. The approach used mice that were awake and mice that were under general anesthesia. Our results demonstrate that not only the behavioral training enables IOP measurement from conscious mice without using a restrainer, it also significantly improves the consistency and reliability of the IOP measurement. In addition, we provide a direct comparison between awake and anesthetized IOP measurements as a function of time after the induction of general anesthesia with several commonly used anesthetic agents. We found that all tested general anesthetics significantly altered the IOP measurements both in normal eyes and in those with elevated IOP. Therefore, we conclude that behavioral training of mice can provide an approach to measure awake IOP that does not require general anesthesia and thus produces reliable and consistent results.

Evolution of central corneal thickness in children with congenital glaucoma requiring glaucoma surgery

BACKGROUND

The purpose of the study was to investigate the evolution of central corneal thickness (CCT) in correlation to the intraocular pressure (IOP) in children with congenital glaucoma before and after glaucoma surgery.

METHODS

Nine eyes of five children (age 2 weeks to 6 months, mean 23 weeks) underwent trabeculotomy for congenital glaucoma. Corneal ultrasound pachymetry (PacScan 3000 AP, Technomed, Germany), tonometry using the Perkins tonometer, and slit-lamp examination (additionally to a clinical routine examination with retinoscopy, funduscopy, measurement of axial length and corneal diameter) were performed before and for at least 12 months after glaucoma surgery. In all children, corneal pachymetry and slit-lamp biomicroscopy--and whenever possible applanation tonometry--were performed without sedation or general anesthesia. If measurement of the IOP was not possible otherwise (in four of the five children), sedation with midazolam orally was used to measure the IOP at 2 weeks, 6 weeks, and 3 months after trabeculotomy, then every 3 months.

RESULTS

Six of nine eyes had biomicroscopically clear corneas without visible corneal edema before trabeculotomy. In three eyes, a corneal edema was visible in at least one quadrant of the cornea. Regarding all eyes together, mean CCT was 651 +/- 138 microm before trabeculotomy; this decreased to 592 +/- 119 microm within 2 weeks after trabeculotomy. At 6 weeks and 3 months there was a further regression to 569.4 +/- 16 microm. Mean IOP was 18.6 +/- 7.5 mmHg before and decreased to 14.8 +/- 5.8 mmHg after glaucoma surgery. Regarding IOP data obtained under general anaesthesia, decrease of CCT was significantly correlated with decrease in IOP. There was no significant difference in the correlation between eyes with and without visible corneal edema.

CONCLUSIONS

Corneal ultrasound pachymetry appears to be a valuable additional measure in the follow-up of infants and small children requiring glaucoma surgery.

Desflurane and Sevoflurane in Cardiac Surgery: A Meta-Analysis of Randomized Clinical Trials

OBJECTIVES

The authors performed a meta-analysis to investigate whether the cardioprotective effects of volatile anesthetics translate into decreased morbidity and mortality in patients undergoing cardiac surgery.

BACKGROUND

It is commonly believed that the choice of the primary anesthetic agent does not result in different outcomes after cardiac surgery. Recent evidence, however, has indicated that volatile anesthetics improve postischemic recovery at a cellular level, in isolated hearts, in animals, and in humans.

METHODS

Four investigators independently searched BioMedCentral and PubMed. Inclusion criteria were random allocation to treatment and comparison of a total intravenous anesthesia regimen versus an anesthesia plan including desflurane or sevoflurane performed on cardiosurgical patients. Exclusion criteria were duplicate publications, nonhuman experimental studies, and no outcome data. The endpoints were the rate of perioperative myocardial infarction and hospital mortality.

RESULTS

The search yielded 22 studies, involving 1,922 patients. Volatile anesthetics were associated with significant reductions of myocardial infarctions (24/979 [2.4%] in the volatile anesthetics group v 45/874 [5.1%] in the control arm, odds ratio [OR] = 0.51 [0.32-0.84], p for effect = 0.008, and p for heterogeneity = 0.77) and mortality (4/977 [0.4%] v 14/872 [1.6%], OR = 0.31 [0.12-0.80], p for effect = 0.02, and p for heterogeneity = 0.88).

CONCLUSIONS

Desflurane and sevoflurane have cardioprotective effects that result in decreased morbidity and mortality. The present data show for the first time that the choice of an anesthetic regimen based on administration of halogenated anesthetics is associated with a better outcome after cardiac surgery.

The general anesthetic propofol increases brain N-arachidonylethanolamine (anandamide) content and inhibits fatty acid amide hydrolase

1. Propofol (2,6-diisopropylphenol) is widely used as a general anesthetic and for the maintenance of long-term sedation. We have tested the hypothesis that propofol alters endocannabinoid brain content and that this effect contributes to its sedative properties. 2. A sedating dose of propofol in mice produced a significant increase in the whole-brain content of the endocannabinoid, N-arachidonylethanolamine (anandamide), when administered intraperitoneally in either Intralipid or emulphor-ethanol vehicles. 3. In vitro, propofol is a competitive inhibitor (IC(50) 52 micro M; 95% confidence interval 31, 87) of fatty acid amide hydrolase (FAAH), which catalyzes the degradation of anandamide. Within a series of propofol analogs, the critical structural determinants of FAAH inhibition and sedation were found to overlap. Other intravenous general anesthetics, including midazolam, ketamine, etomidate, and thiopental, do not affect FAAH activity at sedative-relevant concentrations. Thiopental, however, is a noncompetitive inhibitor of FAAH at a concentration of 2 mM. 4. Pretreatment of mice with the CB(1) receptor antagonist SR141716 (1 mg kg(-1), i.p.) significantly reduced the number of mice that lost their righting reflex in response to propofol. Pretreatment of mice with the CB(1) receptor agonist, Win 55212-2 (1 mg kg(-1), i.p.), significantly potentiated the loss of righting reflex produced by propofol. These data indicate that CB(1) receptor activity contributes to the sedative properties of propofol. 5. These data suggest that propofol activation of the endocannabinoid system, possibly via inhibition of anandamide catabolism, contributes to the sedative properties of propofol and that FAAH could be a novel target for anesthetic development.