Anaphylactoid reaction to etomidate: report of a case

We report an anaphylactoid reaction to etomidate twice in a 60-year-old male with coronary artery disease and peripheral vascular disease. Following the first anaphylactoid reaction, the patient developed myocardial infarction. In addition, the patient's blood was moderately positive for latex antibodies, which made the differential diagnosis difficult. We concluded that the patient had anaphylactoid reaction to etomidate due to the temporal relationship to induction with the drug. The patient did not manifest similar reaction to other induction drugs used for other surgeries. The patient recovered from both incidents of anaphylactoid reaction to etomidate following intravenous administration of epinephrine and fluids.

Management of anesthesia in geriatric patients undergoing head and neck surgery

Surgical outcomes of patients aged 65 and older depend in part on the patient's physiologic status and coexisting disease and whether the surgery is elective or urgent. As our overall population continues to grow older, more elderly patients with head and neck cancers are being scheduled for surgery. In addition to the usual problems of aging, older head and neck surgery patients have unique airway issues that must be addressed preoperatively. Likewise, thorough planning for perioperative management is imperative to reduce morbidity and mortality. Because pharmacokinetics and pharmacodynamics are different in older patients than in younger patients, the administration of anesthesia must be adjusted accordingly.

Significance of atrial septal aneurysm: report of a case

Postoperative stroke can have many etiologies including cerebral thrombosis, embolism, and hemorrhage. If there is a right-to-left intracardiac shunt, paradoxical embolism may also occur. Atrial septal aneurysm has been diagnosed with increasing frequency because of the accuracy of transesophageal echocardiography (TEE). Atrial septal aneurysm is also associated with patent foramen ovale and atrial septal defects. We report a case of a patient who developed a postoperative stroke one day after coronary artery bypass surgery. TEE performed in the intensive care unit revealed an atrial septal aneurysm with a right-to-left interatrial shunt, which may have resulted in paradoxical systemic embolism.

Changes in intraocular pressure during low dose intravenous sedation with propofol before cataract surgery

AIMS

This study examined the effects on intraocular pressure, pulse rate, and blood pressure of low dose intravenous sedation with propofol.

METHODS

Twenty adult patients who were scheduled to undergo cataract surgery were given a single intravenous bolus (0.98 (SEM 0.4) mg/kg) of propofol for sedation before administering the local anaesthetic for cataract surgery. A small intravenous dose of lignocaine was the only other anaesthetic or sedative agent given. The intraocular pressure in the non-surgery eye, the pulse rate, and the blood pressure were measured before and after propofol induction.

RESULTS

Compared with the preinduction baseline, there was a 17% to 27% (from 16.2 (0.7) mm Hg to 11.8 (0.7) mm Hg) decrease in intraocular pressure after propofol induction. A significant decrease in intraocular pressure occurred within the first minute and was still evident at 7 minutes when the measurements were stopped. There was also a 7%-12% increase in pulse rate during the first 4 minutes, a 12% decrease in mean systolic blood pressure, and a 7% decrease in mean diastolic blood pressure from baseline after propofol induction.

CONCLUSION

A single low dose bolus of propofol used for sedation before cataract surgery caused a moderate reduction in intraocular pressure with minimal, easily managed side effects.

Increased cerebral and decreased femoral artery blood flow velocities during direct laryngoscopy and tracheal intubation

Direct laryngoscopy and tracheal intubation may be associated with increased heart rate, arterial blood pressure, cardiac index, and systemic vascular resistance. These responses have been attributed to sympathoadrenal stimulation. However, the studies measuring distribution of blood flow to various organs are limited. We prospectively evaluated blood flow velocities in the common carotid, middle cerebral, and femoral arteries before induction of anesthesia, after induction but before direct laryngoscopy, at the conclusion of direct laryngoscopy and tracheal intubation, and 3 min after tracheal intubation in 13 adult patients. Direct laryngoscopy and tracheal intubation produced increases in the heart rate (from 76 +/- 13 to 91 +/- 10 bpm; chi +/- SD), systolic blood pressure (from 168 +/- 20 to 206 +/- 21 mmHg), common carotid and middle cerebral blood flow velocities, but produced decreases in femoral artery blood flow velocities. Common carotid artery blood flow velocity increased from 49.4 +/- 12.5 cm/s to 65.2 +/- 20.7 cm/s (P < 0.05) at the conclusion of tracheal intubation. Middle cerebral artery blood flow velocity, which could be measured only in seven patients due to technical difficulties secondary to movement during laryngoscopy, increased from 62.4 +/- 20.5 cm/s to 78.0 +/- 27.7 cm/s (P < 0.05). In contrast, femoral artery blood flow velocity decreased from 107.6 +/- 37.8 cm/s to 76.8 +/- 28.6 cm/s (P < 0.05). These responses suggest that the hypertensive response due to direct laryngoscopy and tracheal intubation is associated with redistribution of blood flow in the body.

Brachial plexus block. A comparison of the supraclavicular lateral paravascular and axillary approaches

BACKGROUND AND OBJECTIVES

Anesthesia of the brachial plexus has been associated with injuries to adjacent structures (e.g., pneumothorax, vascular penetration). It is not uncommon to have only partial block of the upper extremity, hindering completion of the surgical procedure. The supraclavicular lateral paravascular approach to brachial plexus anesthesia has been proposed as an effective, safe alternative to the traditional approaches to brachial plexus anesthesia.

METHODS

This prospective, randomized study sought to determine if the supraclavicular lateral paravascular (SCLP) approach is as effective as the transarterial axillary approach, the most common brachial plexus block used at our institution.

RESULTS

16/20 (80%) of SCLP blocks were good. 13/20 axillary blocks were good. The success rate with the SCLP approach was 95%. The success rate with the axillary approach was 90%.

CONCLUSIONS

The supraclavicular lateral paravascular approach is as effective as the axillary approach.

Excitatory effects and electroencephalographic correlation of etomidate, thiopental, methohexital, and propofol

Excitatory movements have been observed during induction of anesthesia with etomidate, thiopental, methohexital, and propofol. We studied the frequency of these excitatory effects and correlated movements with electroencephalographic (EEG) findings in 67 unpremedicated patients (mean age 66.1 yr, range 45-82 yr). Excitatory effects, including myoclonus, tremor, and dystonic posturing, occurred in 86.6% of patients receiving etomidate; 69.2% of the patient responses were myoclonic. Multiple spikes appeared on the EEG in 22.2% of the etomidate patients. The frequency of excitatory effects was 16.6% after thiopental, 12.5% after methohexital, and 5.5% after propofol. None of the patients receiving thiopental, methohexital, or propofol developed myoclonic or seizure activity. In most patients, the excitatory movements were coincident with the early slow phase of the EEG which corresponds to the beginning of deep anesthesia. We conclude that perhaps caution should be exercised when administering etomidate to patients with a history of seizures as the myoclonic activity is associated with seizure activity. The incidence of excitatory movements after administration of propofol is very low.

Electroencephalographic changes from hyponatremia during transurethral resection of the prostate

A patient undergoing transurethral resection of the prostate suffered hyponatremia during the perioperative period. Electroencephalography demonstrated diffuse slowing although the patient was not clinically encephalopathic. The serum sodium level may indicate a trend toward development of the transurethral resection syndrome but the sodium level does not necessarily parallel metabolic changes in brain tissue. Consequently, electroencephalography may aid in the early diagnosis and treatment of encephalopathy during the early phases of the transurethral resection syndrome.

Loss of hypoxic ventilatory response following bilateral neck dissection

Modified radical neck or combined radical and modified radical neck surgery is performed for treatment of head and neck cancer. Because of the extensive nature of the surgery, including dissection around the carotid vessels, we prospectively evaluated hypoxic ventilatory responses preoperatively and postoperatively in five patients. The change in ventilation to percent desaturation varied between -0.22 and -0.60 L/min per percent desaturation in the five study patients. In the postoperative evaluation, two of five patients showed flattened responses compared with the preoperative measurements due to denervation of their carotid bodies. Two patients showed increased responses due to loss of upper airway resistance from tracheostomy. We conclude that after bilateral neck dissection for cancer surgery some patients may lose their hypoxic ventilatory responses due to carotid body denervation.

Influence of volume on the spread of local anesthetic-methylene blue solution after injection for intercostal block

The purpose of this study was to evaluate the influence of the volume of methylene blue-local anesthetic on the spread of the injectate along the costal pleura. Twenty patients undergoing elective thoracotomy were studied. Twelve patients received intercostal nerve injection with 10 mL of 0.5% bupivacaine with methylene blue (10-mL group), and eight patients received 5 mL of 0.5% bupivacaine with methylene blue (5-mL group). The area of spread of the methylene blue was measured after the pleural cavity was incised. The 10-mL group had a mean area of spread of 51.1 cm2 as opposed to 17.6 cm2 for the 5-mL group (P less than 0.05). In the 10-mL group, eight patients had bupivacaine-methylene blue spread to two intercostal spaces, three patients to three intercostal spaces, and one patient to four intercostal spaces. In the 5-mL group, seven patients had bupivacaine methylene blue spread confined to one intercostal space and one patient to two intercostal spaces. We conclude that a potential anatomic space exists between the costal pleura and the internal intercostal muscle and that the spread of local anesthetic after intercostal nerve block injection is volume dependent.

An electroencephalographic comparison of effects of propofol and methohexital

Thirty-eight patients were randomly allocated to receive propofol 1 mg/kg (group A, N = 10), methohexital 0.7 mg/kg (group B, N = 9), propofol 2 mg/kg (group C, N = 10), methohexital 1.5 mg/kg (group D, N = 9). They were all male with a mean age of 65.8 years (range, 46-85) and a mean weight of 76.2 kg (range, 50-109). Patients received no premedication. All drugs were administered as a single i.v. bolus. After baseline EEG recordings were obtained, i.v. bolus doses were given and the recording continued until the patients became fully responsive to verbal commands. The EEGs were visually analyzed and classified into 4 phases: phase 0, the wake physiologic pattern; phase 1, initial changes after i.v. bolus doses; phase 2, state of deep anesthesia; and phase 3, stage of recovery. The main change during phase 1 was increase in the amplitude of the background rhythms. Phase 2 was characterized by theta and delta activity and burst suppression in some patients. During phase 3 beta activity was seen following methohexital. Propofol produced a much deeper level of anesthesia compared to methohexital. The stage of deep anesthesia was prolonged following propofol. The clinical and EEG recoveries were prolonged after induction doses of propofol. The quality of recovery, however, was far superior with propofol. Methohexital produces a "hang over" effect which delays full recovery.

Noncardiac surgery in the patient with congenital heart disease

The patient with congenital heart disease who presents for noncardiac surgery requires careful evaluation and planning to avoid adverse perioperative events. This chapter presents a physiological approach to the management of anesthesia for the most common congenital heart lesions. The various congenital heart defects are categorized into lesions resulting in: (1) left-to-right shunting; (2) right-to-left shunting; (3) complete mixing of pulmonary and systemic circulation; (4) complete separation of the pulmonary and systemic circulations; (5) increased myocardial work; and (6) mechanical obstruction of the airway.

Resistance to vecuronium in patients with cerebral palsy

To determine the electromyographic response of patients with cerebral palsy to vecuronium, 10 children (mean age, 6 yr 10 mo) without cerebral palsy and 11 children with cerebral palsy (mean age, 10 yr 3 mo) were studied. All patients were undergoing abdominal or orthopedic surgery and were anesthetized with isoflurane and nitrous oxide. The time from intravenous administration of 0.1 mg/kg of vecuronium to 25% recovery of control twitch height was 43.9 +/- 5.3 and 18.9 +/- 1.7 min (mean +/- SEM) in children without and with cerebral palsy, respectively (P less than 0.01). The authors conclude that patients with cerebral palsy are either resistant to vecuronium or have a rapid clearance as evidenced by the rapid recovery from neuromuscular blockade.

Chest radiograph changes after cardiopulmonary bypass in children

To determine the spectrum of pediatric chest radiograph changes after cardiopulmonary bypass, 98 children (mean age = 5.9 yr, range 4 wk-16 yr) were studied for 3 days postoperatively. Daily A-P radiographs were evaluated for atelectasis, cardiomegaly, pleural effusions, diaphragmatic elevation, mediastinal widening, and pulmonary infiltrates. The overall incidence of atelectasis was 82%, with left lower lobe atelectasis the most common (64%). Right upper lobe atelectasis occurred in 35% of patients, far more common than in the adult. Radiographic changes were then compared with independent variables including patient weight, age, duration of bypass, and fluid balance by multiple linear regression. Pleural effusion correlated with patient weight and duration of bypass. Diaphragmatic elevation correlated with patient weight. Cardiomegaly correlated with patient age. Net fluid balance was a poor predictor of postoperative chest radiograph changes. We conclude that radiographic changes are common after cardiopulmonary bypass in children, that the overall incidence is not markedly different from adults, and that right upper lobe atelectasis occurs more frequently in children.

Was there a retained spinal catheter?

The 28-gauge catheter supplied by Kendall Healthcare Products Company (Mansfield, MA) for continuous spinal anesthesia has two important characteristics. The ink used for the centimeter calibration marks and to identify the tip of the catheter "washes off" while it is inserted in the patient. In addition, the catheter has a tendency to stretch while it is in the patient or being removed. These two characteristics produced a situation in which it was impossible to determine whether a catheter fragment had been left in a patient. This predicament had a serious impact on the postoperative management of the patient. A computerized tomographic scan and spine films were negative, while other evidence suggested that a fragment was left behind. When the patient developed a postdural puncture headache, the authors felt that an epidural blood patch was contraindicated. The patient's headache did resolve with 48 hours of conservative therapy.

A series of truly failed spinal anesthetics

This report describes five patients with failed continuous spinal anesthetics with lidocaine. Lidocaine concentrations of 420 to 880 micrograms/ml were assayed in the spinal fluid despite lack of anesthesia. There was free flow of cerebrospinal fluid (CSF) through the catheter in all patients before and after the injection of lidocaine. Inactive lidocaine was not responsible for the failures, since lidocaine from the same manufacturing batch produced anesthesia in other patients. Incorrect catheter placement could not explain the failures, since bupivacaine injected through the same intraspinal catheter produced anesthesia in four of the five patients. The authors, therefore, suggest that some patients have a physiologic resistance to lidocaine.

Hypoglycemia following bilateral adrenalectomy for pheochromocytoma

Severe hypoglycemia with delayed emergence occurred in a 12-yr-old boy following bilateral adrenalectomy for pheochromocytoma. Hypoglycemia after resection of pheochromocytoma may be due to release of insulin from the beta cells of the pancreas due to sudden withdrawal of catecholamines. Beta blockade with the use of propranolol impairs both hepatic glucose production and glucagon secretion mechanism. For early detection and treatment of hypoglycemia, perioperative blood glucose monitoring is important in patients undergoing adrenalectomy for pheochromocytoma.