Risk factors associated with umbilical vascular catheter-associated thrombosis in newborn infants

OBJECTIVE: To determine the risk factors associated with umbilical vascular catheter-associated thrombosis. METHODS: All consecutive inborn infants with umbilical arterial (UAC) and/or umbilical venous catheters (UVC) inserted for more than 6 h duration were included in the study. Each infant was screened for thrombosis in the abdominal aorta and inferior vena cava by 2-D abdominal ultrasonography within 48-72 h of insertion of umbilical vascular catheters. Subsequent serial scanning was performed at intervals of every 5-7 days, and within 48 h after removal of catheters. RESULTS: Upon removal of umbilical catheters, abdominal aortic thrombi were detected in 32/99 (32.3%) infants with UAC. Small thrombi were detected in the inferior vena cava of 2/49 (4.1%) infants with UVC (one of whom had both UAC and UVC). When compared with those who received only UVC (n = 18), infants who received either UAC alone (n = 68) or both UAC and UVC (n = 31) had significantly higher risk of developing thrombosis (odds ratio (OR): 7.6, 95% confidence interval (CI): 1.1, 325.5)). Logistic regression analysis of various potential risk factors showed that the only significant risk factor associated with the development of abdominal aortic thrombosis following insertion of UAC was longer duration of UAC in situ (for every additional day of UAC in situ, adjusted OR of developing thrombosis was: 1.2, 95% CI: 1.1, 1.3; P = 0.002). CONCLUSION: Umbilical arterial catheter-associated thrombosis was common. Umbilical arterial catheter should be removed as soon as possible when not needed. Upon removal of UAC, all infants should be screened for abdominal aortic thrombus by 2-D ultrasonography.     

Blood sampling via umbilical vein catheters decreases cerebral oxygenation and blood volume in preterm infants

AIM: We have shown previously that blood sampling via umbilical artery catheters decreases cerebral oxygenation and cerebral blood volume in preterm infants. To evaluate alternative methods, we assessed the effects of blood sampling via umbilical vein catheters in a cohort of preterm infants. METHODS: Twenty neonates (median birth weight 900 g [range 410-1900 g], median gestational age 27 weeks [24-31 weeks]) were studied during routine blood sampling via umbilical vein catheters by near-infrared spectroscopy. Tissue oxygenation index and changes in concentrations of cerebral oxygenated and deoxygenated haemoglobin were measured and changes in cerebral oxygenation and cerebral blood volume were calculated. Oxygen saturation and heart rate were recorded simultaneously. RESULTS: There was a significant drop of cerebral oxygenation (-2.135 +/- 0.532 micromol/L) and cerebral blood volume (-0.037 +/- 0.019 mL/100 g tissue) during umbilical vein blood sampling. Although peripheral arterial oxygen saturation remained unchanged, cerebral tissue oxygenation index decreased from 64.8 +/- 2.5% to 62.4 +/- 2.6% (p < 0.01), accompanied by a slight increase in heart rate (from 140 +/- 2.9 to 144 +/- 2.9 beats/min, p < 0.01). CONCLUSIONS: Umbilical vein blood sampling reduces cerebral oxygenation and cerebral blood volume. The magnitude of the effects is similar to those during umbilical artery blood sampling.     

Continuous measurement of cerebral blood volume and oxygenation during rewarming of neonates

AIM: To investigate the effect of rewarming in preterm infants presenting with hypothermia at admission. METHODS: The tissue oxygenation index (TOI), changes in cerebral blood volume (DeltaCBV) and changes in intravascular oxygenation (DeltaHbD) were measured in eight preterm infants, presenting with a temperature less than 35 degrees C at admission. RESULTS: A significant increase in HbD and TOI was seen in four patients (group A), while a significant increase in CBV and a decrease in HbD was seen in four other patients (group B). Retrospective analysis showed that group A had important signs of peripartal asphyxia. CONCLUSION: While infants with peripartal asphyxia showed an important increase in oxygenation during rewarming, no significant changes were seen in the non-asphyxiated infants.     

Umbilical artery catheter blood sampling decreases cerebral blood volume and oxygenation in very low birthweight infants

The aim of this study was to assess whether blood sampling from umbilical artery catheters reduces cerebral blood volume and cerebral oxygenation in very low birthweight infants. A total of 20 infants, median birthweight 890 g (530-1500 g), median gestation age 26 +4 wk (range: 22 +5 to 30 +6 wk) were studied from 10 min before until 10 min after routine blood sampling from umbilical artery catheters placed in the high position. Using near infrared spectroscopy, changes in concentrations of cerebral oxygenated and deoxygenated haemoglobin were measured, and changes in cerebral blood volume and cerebral oxygenation index were calculated. Heart rate, oxygen saturation, transcutaneous PO₂ and PCO₂ were registered continuously. Mean arterial blood pressure was measured before and after sampling. Oxygenated haemoglobin decreased significantly from baseline during blood sampling, whereas deoxygenated haemoglobin did not change significantly. This resulted in a decrease in cerebral blood volume and cerebral oxygenation index. Heart rate increased slightly, but significantly, from baseline. Oxygen saturation, blood pressure, transcutaneous PO₂ and PCO₂ did not change significantly. Conclusion: Blood sampling from umbilical artery catheters induces a significant decrease in cerebral blood volume and cerebral oxygenation.     

Brain haemodynamic effects of nasal continuous airway pressure in preterm infants of less than 30 weeks' gestation

AIM: To evaluate the hypothesis that increasing levels of nasal continuous positive airway pressure (NCPAP) may decrease cerebral blood volume (CBV) and cerebral oxygenation in infants with gestational age (GA) less than 30 weeks. METHODS: We prospectively studied a cohort of preterm infants treated with NCPAP using near-infrared spectroscopy (NIRS). The pressure limit of NCPAP was set at 2, 4, 6 and again 2 cm H(2)O for 30 min. RESULTS: Changes of pressure levels were not followed by significant changes of oxygenated haemoglobin (O(2)Hb), deoxygenated haemoglobin (HHb), cerebral intravascular oxygenation (HbD), oxidized-reduced cytochrome aa3 (CtOx), tissue oxygenation index (TOI), tissue haemoglobin index (THI) and cerebral blood volume (DeltaCBV). CONCLUSION: NCPAP at 2-6 cm H(2)O pressure levels did not affect cerebral oxygenation and CBV. These findings are reassuring and confirm the safety of NCPAP in preterm infants with GA less than 30 weeks.     

Effects of midazolam and morphine on cerebral oxygenation and hemodynamics in ventilated premature infants

BACKGROUND: Midazolam sedation and morphine analgesia are commonly used in ventilated premature infants. OBJECTIVES: To evaluate the effects of midazolam versus morphine infusion on cerebral oxygenation and hemodynamics in ventilated premature infants. METHODS: 11 patients (GA 26.6-33.0 weeks, BW 780-2,335 g) were sedated with midazolam (loading dose 0.2 mg/kg, maintenance 0.2 mg/kg/h) and 10 patients (GA 26.4-33.3 weeks, BW 842-1,955 g) were sedated with morphine (loading dose 0.05 mg/kg, maintenance 0.01 mg/kg/h). Changes in oxyhemoglobin (Delta cO2Hb) and deoxyhemoglobin (Delta cHHb) were assessed using near infrared spectrophotometry. Changes in cHbD (= Delta cO(2)Hb - Delta cHHb) reflect changes in cerebral blood oxygenation and changes in concentration of total hemoglobin (Delta ctHb = Delta cO2Hb + Delta cHHb) represent changes in cerebral blood volume (DeltaCBV). Changes in cerebral blood flow velocity (DeltaCBFV) were intermittently measured using Doppler ultrasound. Heart rate (HR), mean arterial blood pressure (MABP), arterial oxygen saturation (saO2) and transcutaneous measured pO2 (tcpO2) and pCO2 (tcpCO2) were continuously registered. Statistical analyses were carried out using linear mixed models to account for the longitudinal character study design. RESULTS: Within 15 min after the loading dose of midazolam, a decrease in saO2, tcpO2 and cHbD was observed in 5/11 infants. In addition, a fall in MABP and CBFV was observed 15 min after midazolam administration. Immediately after morphine infusion a decrease in saO2, tcpO2 and cHbD was observed in 6/10 infants. Furthermore, morphine infusion resulted in a persistent increase in CBV. CONCLUSIONS: Administration of midazolam and morphine in ventilated premature infants causes significant changes in cerebral oxygenation and hemodynamics, which might be harmful.     

Brain hemodynamic effects of doxapram in preterm infants

BACKGROUND: Doxapram is a respiratory stimulant widely used for the treatment of idiopathic apnea of prematurity, although it has been demonstrated that it can induce a transient decrease of cerebral blood flow and that isolated mental delay in infants weighing <1,250 g is associated with the total dosage and duration of doxapram therapy. OBJECTIVES: To evaluate the effects of doxapram on cerebral hemodynamics in preterm infants using cerebral Doppler ultrasonography and near-infrared spectroscopy. METHODS: Preterm infants who required treatment with doxapram for apnea of prematurity unresponsive to caffeine were treated with doxapram at an hourly dose of 0.5 mg x kg(-1).h(-1), followed by 1.5 and 2.5 mg x kg(-1).h(-1). RESULTS: 20 preterm infants were studied. Doxapram induced a significant decrease of oxygenated hemoglobin (O(2)Hb) and cerebral intravascular oxygenation (HbD = O(2)Hb - HHb) and an increase of HHb and CtOx concentrations, while cerebral blood volume and cerebral blood flow velocity did not change. CONCLUSIONS: Doxapram infusion induces the increase of cerebral oxygen consumption and requirement and the contemporary decrease of oxygen delivery probably mediated by a decrease of cerebral blood flow. Caution must be recommended in prescribing this drug for apnea of prematurity.     

Effects of rapid versus slow infusion of sodium bicarbonate on cerebral hemodynamics and oxygenation in preterm infants

BACKGROUND: Sodium bicarbonate (NaHCO3) is often used for correction of metabolic acidosis in preterm infants. The effects of NaHCO3 administration on cerebral hemodynamics and oxygenation are not well known. Furthermore, there is no consensus on infusion rate of NaHCO3. OBJECTIVES: To evaluate the effects of rapid versus slow infusion of NaHCO3 on cerebral hemodynamics and oxygenation in preterm infants. METHODS: Twenty-nine preterm infants with metabolic acidosis were randomized into two groups (values are mean +/-SD): In group A (GA 30.5 +/- 1.7 weeks, b.w. 1,254 +/- 425 g) NaHCO3 4.2% was injected as a bolus. In group B (GA 30.3 +/- 1.8 weeks, b.w. 1,179 +/- 318 g) NaHCO3 4.2% was administered over a 30-min period. Concentration changes of oxyhemoglobin (cO2Hb) and deoxyhemoglobin (cHHb) were assessed using near infrared spectrophotometry. Changes in HbD (= cO2Hb - cHHb) represent changes in cerebral blood oxygenation and changes in ctHb (= cO2Hb + cHHb) reflect changes in cerebral blood volume. Cerebral blood flow velocity was intermittently measured using Doppler ultrasound. Longitudinal data analysis was performed using linear mixed models (SAS procedure MIXED), to account for the fact that the repeated observations in each individual were correlated. RESULTS: Administration of NaHCO3 resulted in an increase of cerebral blood volume which was more evident if NaHCO3 was injected rapidly than when infused slowly. HbD and cerebral blood flow velocity did not show significant changes in either group. CONCLUSION: To minimize fluctuations in cerebral hemodynamics, slow infusion of sodium bicarbonate is preferable to rapid injection.     

Effects of umbilical arterial catheterization on mesenteric hemodynamics

Impairment of mesenteric blood flow due to the use of umbilical artery catheters (UAC) may increase the risk of necrotizing enterocolitis (NEC) in newborn infants. We used Duplex Doppler sonography to investigate the degree of vessel obstruction due to UAC and their effect on visceral hemodynamics in 12 newborn infants. Ultrasonography was performed before and immediately after removal of the UAC, which was positioned above the ostia of the celiac and superior mesenteric arteries (SMA). Vessel diameter, peak systolic blood flow velocity (PSFV), end diastolic blood flow velocity (EDFV), and Pourcelot's resistance index (RI) were measured in the celiac trunk and the SMA within 1 cm of their origins. Removal of the UAC led to a significant increase in mean PSFV (celiac trunk: 50 cm/s ± 15 vs 62 cm/s ± 0.22,P < 0.05; SMA: 52 cm/s ± 0.17 vs 72 cm./s ± 0.21,P < 0.05). RI increased from 0.7 ± 0.14 to 0.74 ± 0.13 and from 0.73 ± 0.1 to 0.76 ± 0.13 for the celiac trunk and SMA, respectively. The EDFV and vessel diameters did not change significantly after UAC removal. Our results suggest that UAC cause a decrease in mesenteric blood flow. Therefore, their use in hemodynamically unstable neonates or in those with gastrointestinal disease should be very carefully considered.     

Fluctuating pressure-passivity is common in the cerebral circulation of sick premature infants

Cerebral blood flow pressure-passivity results when pressure autoregulation is impaired, or overwhelmed, and is thought to underlie cerebrovascular injury in the premature infant. Earlier bedside observations suggested that transient periods of cerebral pressure-passivity occurred in premature infants. However, these transient events cannot be detected reliably by intermittent static measurements of pressure autoregulation. We therefore used continuous bedside recordings of mean arterial pressure (MAP; from an indwelling arterial catheter) and cerebral perfusion [using the near-infrared spectroscopy (NIRS) Hb difference (HbD) signal) to detect cerebral pressure-passivity in the first 5 d after birth in infants with birth weight <1500 g. Because the Hb difference (HbD) signal [HbD = oxyhemoglobin (HbO2) - Hb] correlates with cerebral blood flow (CBF), we used coherence between MAP and HbD to define pressure-passivity. We measured the prevalence of pressure-passivity using a pressure-passive index (PPI), defined as the percentage of 10-min epochs with significant low-frequency coherence between the MAP and HbD signals. Pressure-passivity occurred in 87 of 90 premature infants, with a mean PPI of 20.3%. Cerebral pressure-passivity was significantly associated with low gestational age and birth weight, systemic hypotension, and maternal hemodynamic factors, but not with markers of maternal infection. Future studies using consistent serial brain imaging are needed to define the relationship between PPI and cerebrovascular injury in the sick premature infant.     

Total parenteral alimentation via indwelling umbilical catheters in the newborn period

Total parenteral alimentation (TPA) was delivered to 80 infants via indwelling umbilical artery and to 9 via indwelling umbilical venous catheters. The primary indication for catheter placement and maintenance was monitoring of arterial blood gases (umbilical venous catheter tip in left atrium) in a group of sick neonates requiring increased inspired oxygen or assisted ventilation. Results were compared with those from 23 infants who had tunnelled jugular catheters for a variety of chronic medical and surgical problems preventing gastric or intestinal feeding. A mean weight gain was achieved in both groups. Mortality and morbidity rates were similar in both groups. The most common complications were infection and thrombotic phenomena. Metabolic complications were few. It is concluded that infusing TPA solutions via indwelling umbilical catheters presents no greater risk than infusion via tunnelled jugular catheters, and provides a method for supplying adequate caloric intake for growth during the acute stage of illness.     

Brain hemodynamic changes in preterm infants after maintenance dose caffeine and aminophylline treatment

OBJECTIVE: To investigate the acute effects of low-dose caffeine and aminophylline on cerebral blood flow in preterm infants, using both near-infrared spectroscopy (NIRS) and cerebral Doppler ultrasonography. METHODS: Preterm infants with a gestational age of <32 weeks and birth weight of <1,500 g were randomized to receive either caffeine or aminophylline treatment for apnea of prematurity. The study period went from 30 min before to 60 min after the administration of the maintenance dose of pure caffeine (2.5 mg/kg once a day) or aminophylline (1.25 mg/kg twice a day). NIRS was used to measure changes in oxygenated hemoglobin (O(2)Hb), deoxygenated hemoglobin (HHb), oxidized-reduced cytochrome aa3 (CtOx), and mean cerebral oxygen saturation (SmO(2) = O(2)Hb/total Hb). Changes in cerebral blood volume (DeltaCBV) after caffeine or aminophylline administration were calculated. Cerebral blood flow velocity (CBV) in the pericallosal artery was evaluated by cerebral Doppler ultrasounds. RESULTS: Data collected by NIRS and cerebral Doppler ultrasounds did not show significant differences before and after caffeine treatment. We observed a significant increase in O(2)Hb and HHb concentration and in CBV at 30 min after the infusion of aminophylline, which tended to return to baseline at the end of the study period. CONCLUSION: Caffeine does not significantly affect brain hemodynamics, while aminophylline induces a significant transient increase in O(2)Hb and HHb concentration and CBV.     

Identification of pressure passive cerebral perfusion and its mediators after infant cardiac surgery

Cerebrovascular pressure autoregulation (CPA) regulates cerebral blood flow (CBF) in relation to changes in mean arterial blood pressure (MAP). Identification of a pressure-passive cerebral perfusion and the potentially modifiable physiologic factors underlying it has been difficult to achieve in sick infants. We previously validated the near-infrared spectroscopy-derived hemoglobin difference (HbD) signal (cerebral oxyhemoglobin - deoxyhemoglobin) as a reliable measure of changes in CBF in animal models. We now sought to determine whether continuous measurements of DeltaHbD would correlate to middle cerebral artery flow velocity (CBFV), allow identification and quantification of pressure-passive state, and help to delineate potentially modifiable factors. We enrolled 43 infants (2 d to 7 mo old) who were undergoing open cardiac surgery and cardiopulmonary bypass. At 6 and 20 h after surgery, we measured changes in HbD, CBFV (by transcranial Doppler), and MAP at different end-tidal CO(2) levels. We assigned a pressure-passive index (PPI) to each study on the basis of the relative duration of significant coherence between DeltaMAP and DeltaHbD. We found a significant relationship between DeltaHbD and DeltaCBFV at both time points. At 6 h after surgery, we showed high concordance (coherence > 0.5; PPI > or = 41%) between DeltaMAP and DeltaHbD, consistent with disturbed CPA in 13% of infants. End-tidal CO(2) values > or = 40 mm Hg and higher MAP variability both were associated with increased odds (p < 0.001) of autoregulatory failure. This approach provides a means to identify and quantify disturbances of CPA. High CO(2) levels and fluctuating MAP are two important preventable factors associated with disturbed CPA.     

Total parenteral alimentation via indwelling umbilical catheters in the newborn period.

Total parenteral alimentation (TPA) was delivered to 80 infants via indwelling umbilical artery and to 9 via indwelling umbilical venous catheters. The primary indication for catheter placement and maintenance was monitoring of arterial blood gases (umbilical venous catheter tip in left atrium) in a group of sick neonates requiring increased inspired oxygen or assisted ventilation. Results were compared with those from 23 infants who had tunnelled jugular catheters for a variety of chronic medical and surgical problems preventing gastric or intestinal feeding. A mean weight gain was achieved in both groups. Mortality and morbidity rates were similar in both groups. The most common complications were infection and thrombotic phenomena. Metabolic complications were few. It is concluded that infusing TPA solutions via indwelling umbilical catheters presents no greater risk than infusion via tunnelled jugular catheters, and provides a method for supplying adequate caloric intake for growth during the acute stage of illness.     

Noninvasive detection of changes in cerebral blood flow by near-infrared spectroscopy in a piglet model of hydrocephalus

Formulation of rational interventions in infantile hydrocephalus is limited by the inability to monitor cerebral hemodynamics quantitatively, continuously, and noninvasively. Near-infrared spectroscopy (NIRS) measures changes in cerebral concentration of oxygenated and deoxygenated hemoglobin (HbO(2) and Hb); HbD is the derived difference between HbO(2) and Hb. Our previous work showed that HbD reflected cerebral blood flow (CBF) measured by radioactive microspheres in a piglet model of systemic hypotension. This study was designed to determine whether NIRS detected important changes in cerebral perfusion and oxygenation in a piglet model of hydrocephalus and whether changes in HbD accurately reflected changes in CBF. Acute hydrocephalus was produced in neonatal piglets by intraventricular infusion of "mock cerebrospinal fluid." Intracranial pressure (ICP) was maintained for several minutes at approximately 10, 20, and 30 mm Hg above the baseline ICP. CBF was measured in cerebral cortex, white matter, and basal ganglia at each ICP by radioactive microspheres. Changes in HbO(2) and Hb were measured continuously by NIRS. Cerebral perfusion pressure declined with increasing ICP, and this decline was accompanied by significant decreases in HbD measured by NIRS and CBF measured by radioactive microspheres. There was a strong correlation between changes in HbD and individual changes in CBF in cerebral cortex, white matter, and basal ganglia (all p < 0.0001). This study demonstrates that changes in HbD reflect changes in CBF over a wide range of ICP in a model of acute hydrocephalus. This reproducible and easily obtained measurement by NIRS could facilitate considerably decisions concerning therapeutic interventions.     

Effect of tilting on cerebral haemodynamics in preterm infants with periventricular leucencephalomalacia

Aim: Measurement of cerebral haemodynamics to detect impaired cerebral blood flow and impaired cerebral autoregulation might make prevention of brain lesions and especially periventricular leucencephalomalacia (PVL) achievable. Methods: Changes in cerebral blood volume (CBV) and the cerebral haemoglobin oxygenation index (cHbD) following tilting up and down in 10 preterm infants with PVL and 25 preterm infants without PVL, measured by near infrared spectroscopy (NIRS), were analysed. Tilting manoeuvres were recorded with a polysomnographic system in combination with NIRS. CBV and cHbD of the baseline phase (1 min before tilting) were compared with data from the post-tilting phase (1 min after tilting). Results: Changes in CBV and cHbD after tilting were significantly pronounced in infants with PVL compared with infants without PVL. CBV decreased in infants with PVL, by -0.099 ± 0.081 ml 100 g ^-1 brain (mean ± SD) after tilting up, and increased by 0.106 ± 0.104 ml 100 g ^-1 brain after tilting down. CBV decreased in infants without PVL, by -0.041 ± 0.068 ml 100 g ^-1 brain after tilting up, and increased by 0.020 ± 0.096 ml 100 g ^-1 brain after tilting down. cHbD showed similar changes after tilting.

Conclusion: Changes in CBV and cHbD after tilting were pronounced in preterm infants with PVL and this may indicate reduced cerebral autoregulatory capacity.     

Effect of pneumothorax-induced systemic blood pressure alterations on the cerebral circulation in newborn dogs

Pneumothorax has been associated with intraventricular hemorrhage in premature infants, although the mechanism for this relationship is not clear. Because alterations in cerebral blood flow are believed to be important in the pathogenesis of intraventricular hemorrhage, the effect of induced pneumothorax and subsequent evacuation on the cerebral circulation in 16 newborn dogs was evaluated. Continuous Doppler ultrasound was used to monitor changes in cerebral blood velocity. Pneumothorax was induced by slow infusion (5 cc/kg/min) or rapid infusion (5 to 10 seconds) of air to reduce mean arterial blood pressure to half of base-line levels. Both methods of pneumothorax induction resulted in significant elevations of central venous pressure and intrapleural pressure, whereas mean arterial blood pressure and cerebral blood velocity decreased significantly. In each group, the pneumothorax was evacuated either by slow withdrawal of air (10 cc/kg/min) or as rapidly as possible. Rapid evacuation of air resulted in an immediate increase in mean arterial blood pressure and cerebral blood velocity to supranormal levels. Slow evacuation led to a more gradual normalization of mean arterial blood pressure and cerebral blood velocity. It is suggested that the precipitous increases in mean arterial blood pressure and cerebral blood velocity following rapid evacuation of a tension pneumothorax may account for the observed association between pneumothorax and intraventricular hemorrhage in premature infants.     

基于中国新生儿协作网的极早产儿中心血管导管使用情况的横断面调查

背景 近年来中国极早产儿救治数量显著增加,中心血管导管已成为国内NICU的常用技术,极早产儿救治中可能存在中心血管导管的不合理使用,但目前尚缺乏其使用现况数据.目的 通过回顾采集和分析中国新生儿协作网(CHNN)数据库正式运行第1年极早产儿中心血管置管现况,并对各医院进行问卷调查,以期发现当前极早产儿中心血管导管使用中...     

Lidocaine for treatment of severe seizures in newborn infants. II. Blood concentrations of lidocaine and metabolites during intravenous infusion

The blood concentrations of lidocaine and its main active metabolites, methylethylglycinexylidide (MEGX) and glycinexylidide (GX), were measured in 24 newborn infants during anticonvulsive treatment with an iv infusion of lidocaine. After a bolus dose of 1.5-2.2 mg/kg and continuous infusion of lidocaine (4.7-6.3 mg/kg/h) there was accumulation of the drug and MEGX within 24 h. After termination of the iv infusion, both lidocaine and the metabolites were eliminated within 24-48 h. The anticonvulsive effectiveness--estimated by clinical observation and continuous amplitude integrated EEG monitoring (cerebral function monitor)--was immediate in 15 infants (nine term and six preterm). There was no correlation between blood concentrations of lidocaine and metabolites, and anticonvulsive effect (i.e. good, intermediate or no response). No differences in blood concentrations were found between full-term and preterm babies, or between infants with or without birth asphyxia. In combination with a fast withdrawal of the drug, few adverse reactions were seen with the dosages used, even though blood concentrations were high. Routine measurements of lidocaine concentrations during anticonvulsive treatment in neonates seem to be of little clinical value. For evaluation of the anticonvulsive effect and for early detection of seizure activity during lidocaine withdrawal, continuous EEG monitoring is preferable.     

Successful clot lysis using low dose of streptokinase in 22 neonates with aortic thromboses

OBJECTIVE: To determine whether intravenous infusion of low dose of streptokinase was effective in lysing umbilical arterial catheter (UAC)-associated aortic thrombi. METHOD: A prospective cohort study of 31 consecutive newborn infants with UAC-associated aortic thrombi which were detected by abdominal ultrasonography after removal of UAC. Twenty-two infants were treated with intravenous infusion of low dose (1000 U/h) streptokinase, while nine others were not treated due to various contra-indications. Thrombolysis occurred after a mean interval of 2.2 days (standard deviation (SD) = 1.8) in the treated infants. In the untreated infants, spontaneous thrombolysis occurred significantly later, after a mean interval of 16.9 days (SD = 14.7) (95% confidence intervals of difference between mean intervals - 26.0, - 3.4; P = 0.02). Only one treated infant developed mild bleeding directly attributed to streptokinase therapy. CONCLUSION: Low dose streptokinase infusion was effective and safe in thrombolysing UAC-associated aortic thrombi.