Right-sided brain lesions in infants following extracorporeal membrane oxygenation

In retrospective review of survivors of neonatal extracorporeal membrane oxygenation, eight patients with varying degrees of right hemispheric brain injury were identified. The extent of preextracorporeal membrane oxygenation hypoxia and ischemia was documented: five of eight patients had arterial PO2 values of less than 40 mm Hg, seven of eight required dopamine for blood pressure support, and five of eight required cardiopulmonary resuscitation. Two patients had proven neurologic abnormalities before extracorporeal membrane oxygenation. Postextracorporeal membrane oxygenation CT brain scans showed right hemispheric focal abnormalities in three patients. Seven infants had neuromotor abnormalities which were lateralizing in nature; all were left sided, suggesting right-sided brain injury. EEGs showed an increased incidence of slowing and attenuation over the right hemisphere. These findings indicate that right-sided brain abnormalities exist after extracorporeal membrane oxygenation and that carotid artery ligation for extracorporeal membrane oxygenation is not without risk.     

Symmetric cerebral blood flow in newborns who have undergone successful extracorporeal membrane oxygenation.

Cerebral blood flow (CBF) was measured with positron emission tomography in 23 newborns following extracorporeal membrane oxygenation. In 9 newborns the common carotid artery was reanastomosed after extracorporeal membrane oxygenation and in 14 newborns the common carotid artery remained ligated. The ratio of right/left hemispheric CBF was not significantly different in the newborns with reanastomosed or occluded common carotid arteries (right/left CBF ratio was 0.98 in both groups). The maximum asymmetry was 8% and was observed in 2 newborns. All 9 newborns with reanastomosis of the carotid artery are normal at follow-up at 1 year or longer. Three newborns with ligation of the common carotid artery were lost to follow-up and 1 newborn died. Eight of 10 remaining newborns are normal at follow-up; the 2 other infants have developmental quotients of 60 and 64, respectively, and no other deficits. The data indicate (1) that hemispheric CBF is symmetric in newborns who have undergone extracorporeal membrane oxygenation and have no evidence of brain injury, and (2) that reanastomosis of the common carotid artery does not alter hemispheric CBF in the newborn period.     

Circle of Willis blood velocity and flow direction after common carotid artery ligation for neonatal extracorporeal membrane oxygenation

The velocity and direction of blood flow in the circle of Willis arteries were measured in three infants who underwent right common carotid artery ligation for extracorporeal membrane oxygenation treatment. Within 15 minutes of common carotid artery ligation, blood flow was detected in one infant's right middle cerebral artery; however, the velocity was reduced to 50% of the preextracorporeal membrane oxygenation level. The velocity remained 50% to 70% lower than normal during the 88 hours of extracorporeal membrane oxygenation therapy. In the other two infants, the velocity changes were less severe. By 2 to 10 weeks after weaning from extracorporeal membrane oxygenation, the velocities in the left cerebral arteries were increased to 116% to 217% of the corresponding right cerebral vessels. Following common carotid artery ligation, a retrograde direction of flow was noted in the first (A1) segment of the right anterior cerebral artery and in the right posterior communicating artery, whereas the direction of flow was normal in the corresponding vessels on the left. After common carotid artery ligation, the vertebrobasilar and the contralateral internal carotid systems appear to be the main sources of reperfusion of the right cerebral hemisphere via the circle of Willis. Furthermore, because of the known variants of the circle anatomy, a noninvasive pulsed Doppler method could be used to evaluate the flow patterns in the circle of Willis arteries, both before and after common carotid artery ligation for extracorporeal membrane oxygenation.     

Internal carotid artery blood flow velocities before, during, and after extracorporeal membrane oxygenation.

Blood flow velocities in the internal carotid arteries were studied with pulsed Doppler in 25 neonatal patients (birth weight range, 2600 to 4100 g) who had extracorporeal membrane oxygenation (ECMO). Time averaged mean systolic, mean diastolic, and mean blood flow velocities were calculated. Five infants had right common carotid artery reconstruction. Blood flow velocities measured in 15 healthy full-term infants were used as controls. Findings during ECMO included the following: (1) forward flow in the right internal carotid artery in 50% of the infants; (2) significant increase in the mean diastolic and the mean flow velocities (48% and 128%, respectively) in the left internal carotid artery when compared with pre-ECMO and control infants' values; (3) the elevation in the mean and the mean diastolic velocities was associated with changes in the PaCO2 and with an increase in the diastolic blood pressure; and (4) forward blood velocities in the right internal carotid artery were comparable with blood velocities in the left internal carotid artery and with the blood velocities of control infants. After ECMO, the mean diastolic velocity in the left internal carotid artery decreased significantly, but it remained elevated when compared with pre-ECMO values. Infants with right common carotid reconstruction had blood velocities in the right internal carotid artery comparable with the simultaneous blood velocities in the left internal carotid artery and to the blood velocities of control infants. Twenty-eight percent of the infants had major neuroanatomic lesions. Right or left preponderance was not noted. No association between blood velocity values in the internal carotid arteries or flow direction and the presence or the absence of brain lesions was noted.     

Carotid artery reconstruction following extracorporeal membrane oxygenation

Right hemispheric brain injury has been noted in surviving infants treated with venoarterial extracorporeal membrane oxygenation (ECMO). This phenomenon may be secondary to permanent ligation of the right carotid artery. At our institution, conventional ventilatory therapy failed in five neonates with respiratory insufficiency, and they were treated successfully with ECMO. In four of the five neonates, the right carotid artery was reconstructed at the time of decannulation. At discharge, all newborns with carotid artery repair showed no signs of unilateral brain injury and had excellent antegrade flow in the right carotid artery as assessed by both duplex and transcranial Doppler ultrasound scanning. Carotid artery reconstruction after ECMO is a technically simple procedure that may reduce the incidence of right hemispheric brain injury and long-term consequences of marginal cerebral perfusion.     

Cerebral proton magnetic resonance spectroscopy of neonates after extracorporeal membrane oxygenation

During venoarterial extracorporeal membrane oxygenation the right carotid artery is ligated in a hypoxic neonate. The aim of the present study was to compare the morphology and metabolism of the left and right basal ganglia in 10 neonates after extracorporeal membrane oxygenation, using proton magnetic resonance imaging and spectroscopy. Data could be obtained in 9 neonates. No significant metabolic differences were found between either the left or right basal ganglia, despite a small right-sided thalamic infarct in one child. Metabolism was normal in all cases. All the infants showed symmetrical neurodevelopment.

Conclusion: Ligation of the right carotid artery for venoarterial extracorporeal membrane oxygenation did not produce persistent changes in brain metabolism in the basal ganglia in this small group of patients.     

Parenchymal and vascular magnetic resonance imaging of the brain after extracorporeal membrane oxygenation

Three-dimensional (volume) magnetic resonance angiography is a new and noninvasive method for imaging the intracranial vasculature. The combination of magnetic resonance angiography and conventional magnetic resonance imaging was used to evaluate brain parenchyma and vessels in 30 survivors of extracorporeal membrane oxygenation. Magnetic resonance imaging findings were abnormal in 33% of the patients, with no increased frequency of right hemispheric lesions. Magnetic resonance angiography demonstrated good intracranial flow in all infants and demonstrable right internal carotid arterial flow in 35% of those patients with permanent carotid ligation. An abnormal magnetic resonance imaging study was found more often in infants with abnormal predischarge neurologic examination results. These techniques have several advantages over other neuroimaging modalities, including better definition of deep structures, myelin formation, and intracranial vasculature, the absence of bone artifact, and the elimination of catheter or contrast use.     

Repeat extracorporeal membrane oxygenation in a neonate: An alternative method for cannulation

Cannulation for repeat extracorporeal membrane oxygenation (ECMO) in neonates with respiratory failure may be associated with technical difficulties, especially after the ligation of both the carotid artery and internal jugular vein. In a newborn who required repeat ECMO, the previously reconstructed right carotid artery was used for arterial access. The right atrium was cannulated through a small submammary thoracotomy incision after the internal jugular vein was found to be thrombosed. This approach is relatively simple, provides excellent bypass flow, and is not associated with significant bleeding.     

Oxygenation and hemodynamics in left and right cerebral hemispheres during induction of veno-arterial extracorporeal membrane oxygenation

OBJECTIVE: Oxygenation and hemodynamics in the left and right cerebral hemispheres were measured during induction of veno-arterial extracorporeal membrane oxygenation (VA-ECMO). STUDY DESIGN: Using near infrared spectrophotometry, effects of right common carotid artery (RCCA) and right internal jugular vein (RIJV) ligation and start of VA-ECMO on concentrations of oxyhemoglobin, deoxyhemoglobin, and cerebral blood volume (CBV) were evaluated in 10 newborn infants. Mean cerebral blood flow velocity (CBFV) in the major cerebral arteries was compared before and after the start of VA-ECMO (pulsed Doppler ultrasonography). RESULTS: RCCA ligation caused a decrease in oxyhemoglobin concentration and an increase in deoxyhemoglobin concentration. RIJV ligation caused no changes. Sixty minutes after the start of VA-ECMO, oxyhemoglobin concentration and CBV had increased, and deoxyhemoglobin concentration had decreased. There were no differences between the hemispheres. Mean CBFV had increased in the left internal carotid artery, and it increased equally in both middle cerebral arteries. Flow direction was reversed in the right internal carotid artery. Three patients had asymmetric cerebral lesions, not related to differences in the measurements between the cerebral hemispheres. CONCLUSION: The initiation of VA-ECMO causes changes in cerebral oxygenation and hemodynamics but without a difference in effect on left and right cerebral hemispheres.     

Bypass circuits as the source of thromboemboli during extracorporeal membrane oxygenation

To determine the presence and extent of thrombus formation in the apparatus used for extracorporeal membrane oxygenation we studied various portions of the polyvinylchloride circuit from five infants who received extracorporeal membrane oxygenation for 70 to 330 hours. All infants had right-sided cannulation. Sections were cut from the circuit at the time of decannulation and subjected to light and scanning electron microscopy. The site that contained the most thrombus formation was the membrane oxygenator bypass circuit, which is subjected to repeated periods of unclamping and clamping to direct blood flow through the membrane oxygenator. Autopsy results from nonsurvivors showed evidence of pulmonary and renal infarcts, a left frontal lobe infarct, a thromboembolus of the left external and internal carotid arteries, and thrombi in the lungs, kidney, brain, and coronary arteries. One survivor had computed tomographic evidence of infarction of the left middle cerebral artery distribution. We suggest that the areas of the extracorporeal membrane oxygenation circuit subjected to repeated changes in flow dynamics may be the source of microemboli.     

Neonatal vocal cord paralysis following extracorporeal membrane oxygenation

Five cases of unilateral vocal cord paralysis/paresis were diagnosed following extracorporeal membrane oxygenation for newborn respiratory failure. All were right sided and transient in nature. None of the five patients had other findings commonly associated with vocal cord palsy. The extracorporeal membrane oxygenation procedure requires surgical dissection in the carotid sheath on the right side of the neck, an area immediately adjacent to both the vagus and recurrent laryngeal nerve. It is speculated that vocal cord paralysis in these infants was acquired as a result of the extracorporeal membrane oxygenation cannulation. Although the vocal cord paralysis resolved in all cases, two patients had difficult courses after extracorporeal membrane oxygenation. Therefore, laryngoscopic examination should be considered for patients after extracorporeal membrane oxygenation.     

Auditory brain-stem responses in neonates receiving extracorporeal membrane oxygenation.

Auditory brain-stem responses from 25 neonates treated with extracorporeal membrane oxygenation were compared with those of 11 control subjects. Results revealed no statistically significant differences for recorded responses, either between ears or between groups. We conclude that infants who receive extracorporeal membrane oxygenation, with or without carotid artery repair, are not at greater risk for auditory brain-stem dysfunction than similar infants who do not receive extracorporeal membrane oxygenation.     

Ocular findings in infants treated with extracorporeal membrane oxygenator support

Eleven infants treated with extracorporeal membrane oxygenator support were examined for ocular complications. Four patients were noted to have retinal and external ocular vascular changes on the left but not on the right. These unilateral findings are believed to be related to right common carotid and internal jugular occlusion. The proposed mechanism involves three factors: cerebral venous congestion, impairment of cerebral and possibly retinal arterial autoregulation, and higher cerebral arterial blood flow on the left compared with the right.     

Cerebral oxygenation in neonatal and pediatric patients during veno-arterial extracorporeal life support.

OBJECTIVE: To observe the effects of right carotid artery ligation and variations in extracorporeal life support (ECLS) flow on regional cerebral oxygenation index (rSO2i) measured using near infrared spectroscopy. DESIGN: Prospective observational study. SETTING: Tertiary children's hospital. PATIENTS: Eleven neonatal and pediatric patients requiring veno-arterial ECLS support between June 2000 and March 2003. INTERVENTIONS: Near infrared spectroscopy probe placement on left and right frontal regions of patients undergoing ECLS, before vessel cannulation or within 24 hrs of initiation of ECLS. MEASUREMENTS AND MAIN RESULTS: Regional cerebral oxygenation was measured every minute for 72 hrs or until the patient was decannulated. The effect of cannulation on rSO2i from each hemisphere of the brain and the relationship between ECLS flow and rSO2i during ECLS support and "trialing off" periods were determined. Ligation of the right carotid artery resulted in a 12-25% decrease in rSO2i from baseline in the right frontal region for a duration ranging from 17 to 45 mins before returning toward baseline. No substantial change in the left frontal region rSO2i was detected during cannulation. Following this depression in rSO2i on the right, there was a transient increase above baseline in rSO2i observed in both hemispheres on initiating ECLS. No correlation between ECLS flow and rSO2i was found over the 72-hr period. Periods of "trialing off" ECLS were not related to any change in rSO2i in either hemisphere. CONCLUSIONS: This study demonstrated no relationship between ECLS flow and rSO2i changes during the 72-hr observation period. A brief period of cerebral oxygen desaturation of the right frontal region at the time of right carotid ligation was seen in all three study patients examined during cannulation, followed by an increased rSO2i with initiation of ECLS flow. Near infrared spectroscopy measurement may offer an important adjunct for neurologic monitoring of ECLS patients.     

听觉诱发电位在重症脑功能检测中的应用

在重症患者中,诱发电位是实时检测神经功能状态、信号传导和感觉信息次级处理进程的重要工具.长潜伏期诱发电位对周围和中枢性感觉传导通路的信号传递进行检测,代表丘脑-皮层和皮层间的复杂信号处理过程.通过重症患者的诱发电位检测,可以了解脑功能状态并进行预后分析.脑干听觉诱发电位(短潜伏期)和听觉刺激的事件相关电位(长潜伏期听觉诱发电位)在重症患者中主要用于:缺氧缺血或创伤性昏迷患者的预后分析、监测神经系统功能好转或衰退、确认脑死亡的发生.短潜伏期脑干诱发电位中Ⅴ波的缺失或分化不良与不良预后相关,但Ⅴ波存在的患者预后不定.近来的研究发现,长潜伏期诱发电位,尤其是听觉刺激错误匹配模式中皮层电位存在及其波幅良好是患者良好预后的特异性指标.对于婴幼儿患者,短潜伏期诱发电位除用于脑损伤的监测外,还用来检测重症患者听觉受累的情况.     

Significance of seizures associated with extracorporeal membrane oxygenation

We previously reported a predominance of left focal motor seizures in infants receiving extracorporeal membrane oxygenation (ECMO), raising concerns about possible ischemia resulting from the right common carotid artery ligation. We therefore evaluated the neurologic and psychologic outcome at 2 years of age of all infants with ECMO-related seizures. Although 8 of 12 infants had left focal seizures in infancy, there was no lateralization of motor findings at 2 years of age; left hemiparesis was present in three of the infants and right hemiparesis in three. The developmental quotient was normal in 6 of 12 infants, low-average in three, borderline in two, and in the mentally handicapped range in one. We conclude that any ischemia resulting from carotid ligation is not great enough to produce long-term lateralizing findings but that seizures during ECMO are a risk factor for later cerebral palsy or developmental delay.     

Sensorineural hearing loss in survivors of neonatal extracorporeal membrane oxygenation

From February 1989 to January 1994, nine of 63 (14.3%) survivors of neonatal extracorporeal membrane oxygenation developed bilateral sensorineural hearing loss. Seven of nine children were tested and passed initial or repeat clinical auditory brainstem response evaluation completed before discharge from neonatal intensive care. Hearing loss was suspected and confirmed between 6–36 and 10–48 months of age, respectively. We recommend regular audiologic follow-up for these high-risk infants until bilateral thresholds for hearing can be obtained.     

Neonatal myocardial infarction and the role of extracorporeal membrane oxygenation

Acute myocardial infarction is a cause of neonatal collapse. The diagnosis is suggested by ischaemic electrocardiography, raised cardiac enzymes and deteriorating cardiac function and should be considered in severe neonatal cardiac dysfunction without other identifiable causes. This paper presents four cases of neonatal myocardial infarction treated with veno-arterial extracorporeal membrane oxygenation (VA ECMO) for cardiorespiratory support. The paper illustrates that left ventricular function may recover after neonatal myocardial infarction if it can be supported for long enough, and that early ECMO referral may be of benefit.     

The natural history of direct hyperbilirubinemia associated with extracorporeal membrane oxygenation.

OBJECTIVE--To determine the incidence and natural history of direct hyperbilirubinemia in neonates treated with extracorporeal membrane oxygenation. DESIGN--A prospective series of patients. SETTING--A level 3 neonatal intensive care unit and center for extracorporeal membrane oxygenation in Ohio. PARTICIPANTS--Sixty-seven consecutive patients treated with extracorporeal membrane oxygenation in 33 months. INTERVENTION--None. MEASUREMENTS/RESULTS--Twenty-six (39%) developed direct hyperbilirubinemia. In 14 (54%), bilirubin levels were mildly elevated and occurred only during extracorporeal membrane oxygenation therapy. Levels were more severely elevated in the remaining 12 patients (46 +/- 10 mumol/L [2.7 +/- 0.6 mg/dL] vs 159 +/- 101 mumol/L [9.3 +/- 5.9 mg/dL], P less than .0001). Duration and severity of hyperbilirubinemia were correlated. Hyperbilirubinemia resolved in all patients by 9 weeks after extracorporeal membrane oxygenation therapy. No structural abnormalities or infectious agents were identified as causes. Aluminum levels were evaluated for 40 patients, were not in the toxic range, and did not correlate with hyperbilirubinemia. Multiple linear regression analysis suggested that hyperbilirubinemia in these cases resulted from interaction of injuries, with the primary contributor being hemolysis during extracorporeal membrane oxygenation. CONCLUSIONS--Direct hyperbilirubinemia occurs frequently in patients treated with extracorporeal membrane oxygenation and may be severe. However, direct hyperbilirubinemia typically resolves without short-term sequelae. Hemolysis may be an important contributing factor.     

Cerebral function of the guinea pig neonate after chronic intrauterine exposure to khat (Catha edulis Forsk.)

Cerebral function in normoxia and its reactions to standard periods of hypoxia of increasing severity were studied in 30 newborn guinea pigs less than 3 days old. Intrauterine growth retardation was induced either by uterine artery ligation at midgestation or by feeding the female in late gestation with khat leaves, an amphetamine-like stimulant chewed by men and women in several countries in eastern Africa and Arabia. After spontaneous delivery, the neonates were anesthetized and ventilated. Cardiovascular, metabolic, and neurophysiologic (somatosensory evoked potentials) parameters were monitored. Under normoxia, the khat-exposed group showed prolonged latency of the primary response of the somatosensory evoked potentials and a reduced amount of secondary components. Under hypoxia, this group also has a greater reduction of amplitude of the somatosensory evoked potentials. It is concluded that khat exposure during fetal life has an impact on the cerebral function during the neonatal period (at least up to 3 days of age) which is not solely explained by the concomitantly produced growth retardation.