Ocular malformations, moyamoya disease, and midline cranial defects: a distinct syndrome

PURPOSE

To report a 10-year-old girl with developmental anomalies of both optic disks, a chorioretinal coloboma, sphenopharyngeal meningoencephalocele, and moyamoya disease.

METHODS

A full ophthalmologic examination, cranial magnetic resonance imaging and magnetic resonance angiography, and cerebral angiography were performed.

RESULTS

The patient had a morning glory disk anomaly and microphthalmos of the right eye and optic nerve hypoplasia and retinochoroidal coloboma in the left eye. She had a midfacial cleft and an episode of seizures and a stroke. Magnetic resonance imaging showed a sphenopharyngeal meningoencephalocele. Magnetic resonance angiography and cerebral angiography demonstrated a pattern consistent with moyamoya disease.

CONCLUSIONS

This patient had a distinct syndrome of optic disk, retinochoroidal, and carotid circulation anomalies with midline cranial defects. The recognition and treatment of the vascular abnormalities and cranial defects may prevent complications such as strokes that may occur during or after general anesthesia.

Effects of gas flow management on postintubation end-tidal anesthetic concentration and operating room pollution

STUDY OBJECTIVE

To study how different anesthetic practices during the transition from anesthetic delivery by mask to endotracheal intubation affect end-tidal postintubation anesthetic concentration and operating room (OR) pollution.

DESIGN

Prospective study.

SETTING

Anesthesia research laboratory.

MEASUREMENTS AND MAIN RESULTS

We studied four gas flow management practices: practice vaporizer off, only the anesthetic vaporizer was turned off; all off, oxygen (O2), nitrous oxide (N2O), and the vaporizer were turned off; gas off: O2 and N2O were turned off; and all on: neither the gas flows nor the vaporizer were turned off. A model of inhalational anesthetic induction was simulated by using an adult circle system attached to a reservoir bag ("artificial lung"). By using a fixed gas flow, we achieved an end-tidal N2O (ETN2O) concentration of 70% and end-tidal halothane (ETHal) concentration of 3%, then stopped mechanical ventilation and performed the four practices for a 30-second "intubation" period. During this time, the reservoir bag was disconnected from the circuit, and the gas volume exiting the circuit (pollution volume) was measured. After this 30-second disconnect period, the bag was reconnected to the anesthetic circuit, and the original ventilation, gas flows, and vaporizer setting were resumed. The anesthetic concentrations were measured at 10, 20, and 30 seconds after reconnection. For the vaporizer off practice, ETHal was low and did not return to equilibrium within 30 seconds (p < 0.05); ETN2O clinically was unaltered. In the all off practice, anesthetic concentrations were below equilibrium at 10, 20, and 30 seconds (p < 0.05). For the gas off practice, ETHal was slightly below equilibrium at all times; ETN2O was below equilibrium at 10, 20, and 30 seconds (p < 0.05). In the all on practice, end-tidal anesthetic concentrations were unchanged when compared with equilibrium (p > 0.05). Pollution volumes in the vaporizer off and all on practices were ten-fold higher than in the all off and gas off practices (p < 0.05).

CONCLUSION

In a mechanical model of anesthetic induction, turning the gas flows off before "intubation" and leaving the vaporizer on (the gas off practice) maintained "postintubation" end-tidal drug concentrations close to "preintubation" equilibrium and minimized OR pollution.

Nitrous oxide impairs functional recovery of stunned myocardium in barbiturate-anesthetized, acutely instrumented dogs

The purpose of this investigation was to characterize the effects of nitrous oxide or nitrogen (70%) on systemic and regional hemodynamics and myocardial tissue perfusion after a brief coronary artery occlusion (15 min) and reperfusion (3 h). Two groups of experiments (14 experiments total) were completed with 24 open-chest, barbiturate-anesthetized dogs. Coronary collateral blood flow was diverted from the ischemic zone during coronary artery occlusion to eliminate a source of variability in degree of ischemia produced by differences in degrees of collateral blood flow among animals. Seven of 16 dogs treated with nitrous oxide and 7 of 8 dogs treated with nitrogen survived coronary occlusion and reperfusion (P less than 0.05). Coronary artery occlusion produced paradoxical systolic bulging in the ischemic zone in both groups of experiments. After reperfusion, segment shortening gradually returned toward control levels but remained depressed from the preocclusion state after 3 h in the nitrogen-treated control group. Similar results were observed after reperfusion in the nitrous oxide group; however, segment function in the ischemic region was significantly (P less than 0.05) depressed throughout the 3-h reperfusion period compared with the control group. Transmural coronary collateral blood flow during occlusion was not significantly different (P greater than 0.05) between groups, indicating that differences in recovery of contractile function observed between groups could not be attributed to differences in myocardial oxygen supply. In addition, the similarity in systemic hemodynamics between the nitrous oxide and control groups indirectly suggests that differences in recovery of function could not be attributed to differences in myocardial oxygen demand. The results indicate that 70% nitrous oxide produces greater mortality after coronary artery occlusion and reperfusion and reduces functional recovery of post-ischemic, reperfused myocardium compared with 70% nitrogen in open-chest, acutely instrumented dogs.

Anesthesia-induced rhabdomyolysis in infants with unsuspected Duchenne dystrophy

Anesthesia-induced rhabdomyolysis in infancy may represent an unsuspected Duchenne dystrophy. In order to establish the diagnosis of this genetic disease more definitively, a dystrophin test is a requisite following the conventional creatine kinase test and light and electron microscopies of the muscle biopsy.

Dose-response for atropine and heart rate in infants and children anesthetized with halothane and nitrous oxide

The dose recommendations for atropine in anesthetized children vary, and the dose-response for heart rate has not been defined. We determined the dose-response for atropine and heart rate in 181 healthy children anesthetized with halothane and nitrous oxide. After induction of anesthesia, atropine in a dose of 5, 10, 20, 30, or 40 micrograms.kg-1 was administered by rapid intravenous infusion of each subject. The effects of atropine on heart rate, heart rhythm, and systolic blood pressure were compared among dosage groups, and a dose-response curve for peak heart rate was constructed. The effects of atropine were compared also between younger and older subjects. For the group of all 181 subjects, atropine increased heart rate in a dose-related manner up to 30 micrograms.kg-1. Fifty percent maximal response corresponded to 9 micrograms.kg-1, and 90% maximal response corresponded to 26 micrograms.kg-1. Some subjects had nonsinus supraventricular rhythms before atropine, but none had nonsinus rhythm after atropine except after the smallest dose, 5 micrograms.kg-1. Systolic blood pressure increased significantly after all doses of atropine except 5 mu.kg-1. Subjects less than 6 months old had higher control and peak heart rates than did subjects greater than or equal to 2 yr old, but the older subjects had greater change in heart rate after atropine. For subjects greater than or equal to 2 yr old, all doses of atropine produced a significant increase in heart rate. The same was true for younger subjects, less than 6 months old, except that 5 micrograms.kg-1 did not increase heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidental cocaine intoxication in a nine-month-old infant: presentation and treatment

A case of a nine-month-old male who ingested cocaine is presented. The rarity of this type of ingestion, as well as the caretaker's denial of the presence of cocaine in the household, made rapid diagnosis of this infant's malady difficult. We present this case to alert physicians to the presentation and treatment of cocaine-intoxicated infants.

Dynamic changes in venous outflow by baroreflex and left ventricular distension

We examined the dynamic changes in venous outflow from the splanchnic and extrasplanchnic vascular beds in response to carotid sinus (CS) baroreflex and left ventricular (LV) distension in 12 dogs anesthetized with pentobarbital sodium. Splenic sympathetic nerve activity was measured in an additional group of six dogs. A heart-lung bypass was used with constant cardiac output and constant venous pressure. LV distension was produced by inflating a balloon in the LV. LV distension and an increase in CS pressure from 50 to 200 mmHg decreased blood pressure by 26 +/- 5 and 30 +/- 6 mmHg and increased vascular capacitance by 5.5 +/- 0.9 and 4.5 +/- 1.2 ml/kg, respectively. Splanchnic venous outflow exhibited a transient decrease, whereas extrasplanchnic venous outflow showed a transient increase, in response to LV distension and increasing CS pressure, accompanied by a sustained decrease in splenic nerve activity. The results indicate important differences between splanchnic and extrasplanchnic components of the total venous system in terms of the regulation of venous capacitance. It is suggested that changes in venous capacitance produced by LV distension and CS baroreflex are primarily due to active changes in splanchnic venous tone.

Left ventricular reflex control of venous return and systemic vascular capacitance in dogs

The reflex effects of left ventricular distension on venous return, vascular capacitance, vascular resistance, and sympathetic efferent nerve activity were examined in dogs anesthetized with sodium pentobarbital. In addition, the interaction of left ventricular distension and the carotid sinus baroreflex was examined. Vascular capacitance was assessed by measuring changes in systemic blood volume, using extracorporeal circulation with constant cardiac output and constant central venous pressure. Left ventricular distension produced by balloon inflation caused a transient biphasic change in venous return; an initial small increase was followed by a late relatively large decrease. Left ventricular distension increased systemic blood volume by 3.8 +/- 0.6 mL/kg and decreased systemic blood pressure by 27 +/- 2 mmHg (1 mmHg = 133.3 Pa) at an isolated carotid sinus pressure of 50 mmHg. These changes were accompanied by a simultaneous decrease in sympathetic efferent nerve activity. When the carotid sinus pressure was increased to 125 and 200 mmHg, these responses were attenuated. It is suggested that left ventricular mechanoreceptors and carotid baroreceptors contribute importantly to the control of venous return and vascular capacitance.

Alteration of blood flow distribution and vascular capacitance during induced hypotension in deafferented dogs

The effects of three hypotensive agents, sodium nitroprusside (SNP), nitroglycerin (NTG), and adenosine triphosphate (ATP), on blood flow distribution and vascular capacitance were examined in dogs anesthetized with sodium pentobarbital. To eliminate the modification by the baroreflex, carotid sinus was denervated and aortic and cardiopulmonary vagal fibers were sectioned. Total systemic circulation was divided into two parallel compartments, splanchnic (SP) and extra-splanchnic (ESP) vascular beds. Alteration of vascular capacitance was assessed by a change in systemic blood volume with constant cardiac output and constant venous pressure using a total heart-lung bypass. SNP- and ATP-induced hypotension caused blood flow redistribution from the SP to ESP beds, and this redistribution is greater (P less than 0.01) with ATP than that with SNP. In contrast, NTG-induced hypotension did not significantly cause redistribution. Systemic blood volume was increased during NTG- (10.4 +/- 2.2 ml/kg), and SNP-induced (4.8 +/- 1.1 ml/kg) hypotension. The increase by NTG was significantly greater (P less than 0.05) than that by SNP. In contrast, ATP-induced hypotension did not significantly change systemic blood volume. Since redistribution can result in a passive change in vascular capacitance, the differences in capacitance among SNP, NTG, and ATP can be explained in part by differences in redistribution of blood flow. Redistribution of blood flow from SP to ESP beds can increase venous return due to increasing the slope of the venous return curve. The results suggest that redistribution should be taken into consideration in evaluating the hemodynamic changes during induced hypotension.