Near-infrared spectroscopic cerebral oxygenation reading in neonates and infants is associated with central venous oxygen saturation

BACKGROUND: The aim of the study was to elucidate easily determinable laboratory and vital parameters in clinical practice to explain variability of near-infrared spectroscopic cerebral oxygenation readings in critically ill newborns and infants using the NIRO 300 spectrometer. METHODS: Near-infrared spectroscopy (NIRS) cerebral tissue oxygenation index (cTOI) was measured on the forehead of critically ill neonates and infants with existing arterial and/or central venous access. We recorded patient characteristics and simultaneously determined sedation state, hemodynamic, respiratory and laboratory data, such as arterial blood gas analysis, electrolytes, hemoglobin and arterial lactate concentration, blood glucose and central venous oxygen saturation. Data were compared using linear, multiple and forward stepwise regression analysis (P < 0.05). RESULTS: A total of 155 neonates and infants aged from 0 to 365 days (median 12 days) were studied. cerebral tissue oxygenation index (cTOI) values ranged from 32.1 to 91.0% (60.5 +/- 11.5%). Simple linear regression analysis revealed significant associations between cTOI and arterial oxygen saturation (r = 0.254, P = 0.001), transcutaneously measured arterial oxygen saturation (r = 0.320, P < or = 0.0001), central venous oxygen saturation (r = 0.489, P < 0.0001), arteriovenous oxygen extraction (r = 0.445, P < 0.0001) and presence of a cardiac shunt (r = 0.250, P = 0.024). Multiple regression analysis and forward stepwise regression revealed two independent, significant predictors for cTOI, namely SvO2 (P < 0.0001) and presence or absence of a cardiac shunt (P = 0.003). SvO2 alone explained 23.9% of the variability of cTOI. The addition of the variable 'cardiac shunt' improved the model to 33%. CONCLUSIONS: Based on our study results cerebral tissue oxygenation readings by the NIRO 300 near-infrared spectrometer is influenced by central venous oxygen saturation, which partially explains intersubject variability of NIRS cerebral oxygenation readings.     

Correlation of oxygen delivery with central venous oxygen saturation, mean arterial pressure and heart rate in piglets

BACKGROUND: Accurate assessment and monitoring of the cardiocirculatory function is essential during major pediatric and pediatric cardiac surgery. Invasive monitoring of cardiac output and oxygen delivery (DO(2)) is expensive and sometimes associated with adverse events. Measurement of central venous oxygen saturation (ScvO(2)) is less invasive and may reflect the DO(2). Therefore, we investigated the correlation of ScvO(2) with cardiac index (CI) and DO(2) and in comparison the more common monitored parameters heart rate (HR) and mean arterial pressure (MAP) with DO(2) in an animal experimental setting. METHODS: In five fasted, anesthetized and mechanically ventilated piglets CI (transpulmonary thermodilution), venous and arterial blood gases, HR and MAP was measured during normal conditions, volume loading, inotropic support, and exsanguination. RESULTS: In the five piglets 168 measurements could be performed. In a wide hemodynamic range (CI 22-335 ml x kg(-1) min(-1)) we found significant correlations of ScvO(2) with DO(2)) (r(2) = 0.91, P < 0.0001) and CI (r(2) = 0.88, P < 0.0001) and also between DO(2) and MAP (r = 0.86, P < 0.0001) and HR (r = 0.19, P < 0.05). CONCLUSIONS: ScvO(2) is a better parameter for indirect estimation of DO(2) than MAP and heart rate. Measurement of ScvO(2) is simple and does not necessitate additional invasive techniques. In the clinical setting ScvO(2) should be used in combination with other standard vital parameters, i.e. MAP, central venous pressure, lactate, base excess, and urine output.     

A noninvasive estimation of mixed venous oxygen saturation using near-infrared spectroscopy by cerebral oximetry in pediatric cardiac surgery patients

BACKGROUND: Near-infrared spectroscopy (NIRS) is a noninvasive optical monitor of regional cerebral oxygen saturation (rSO2). The aim of this study was to validate the use of NIRS by cerebral oximetry in estimating invasively measured mixed venous oxygen saturation (SvO2) in pediatric postoperative cardiac surgery patients. METHODS: Twenty patients were enrolled following cardiac surgery with intraoperative placement of a pulmonary artery (PA) or superior vena cava (SVC) catheter. Five patients underwent complete biventricular repair--complete atrioventricular canal (n=3) and other (n=2). Fifteen patients with functional single ventricle underwent palliative procedures--bidirectional Glenn (n=11) and Fontan (n=4). Cerebral rSO2 was monitored via NIRS (INVOS 5100) during cardiac surgery and 6 h postoperatively. SvO2 was measured from blood samples obtained via an indwelling PA or SVC catheter and simultaneously correlated with rSO2 by NIRS at five time periods: in the operating room after weaning from cardiopulmonary bypass, after sternal closure, and in the CICU at 2, 4, and 6 h after admission. RESULTS: Each patient had five measurements (total=100 comparisons). SvO2 obtained via an indwelling PA or SVC catheter for all patients correlated with rSO2 obtained via NIRS: Pearson's correlation coefficient of 0.67 (P<0.0001) and linear regression of r2=0.45 (P<0.0001). Separate linear regression of the complete biventricular repairs demonstrated an r=0.71, r2=0.50 (P<0.0001). Bland-Altman analysis showed a bias of +3.3% with a precision of 16.6% for rSO2 as a predictor of SvO2 for all patients. Cerebral rSO2 was a more accurate predictor of SvO2 in the biventricular repair patients (bias -0.3, precision 11.8%), compared with the bidirectional Glenn and Fontan patients. CONCLUSIONS: Regional cerebral oximetry via NIRS correlates with SvO2 obtained via invasive monitoring. However, the wide limits of agreement suggest that it may not be possible to predict absolute values of SvO2 for any given patient based solely on the noninvasive measurement of rSO2. Near-infrared spectroscopy, using the INVOS 5100 cerebral oximeter, could potentially be used to indicate trends in SVO2, but more studies needs to be performed under varying clinical conditions.     

Comparison of different near-infrared spectroscopic cerebral oxygenation indices with central venous and jugular venous oxygenation saturation in children

BACKGROUND: We compared two different near-infrared spectrophotometers: cerebral tissue oxygenation index (TOI) measured by NIRO 200 and regional cerebral oxygenation index (rSO(2)) measured by INVOS 5100 with venous oxygen saturation in the jugular bulb (SjO(2)) and central SvO(2) from the superior caval vein (SVC) during elective cardiac catheterization in children. METHODS: A prospective observational clinical study in 31 children with congenital heart defects in a catheterization laboratory was undertaken. TOI was compared with SjO(2) in the left jugular bulb and with SvO(2). rSO(2) was compared with SjO(2) from the right jugular bulb and SvO(2). Linear regression analysis and Pearson's correlation coefficient were calculated and Bland-Altman analyses were performed. RESULTS: Cerebral TOI and SjO(2) were significantly correlated (r = 0.56, P < 0.0001), as well as TOI and SvO(2) with r = 0.74 (P < 0.0001). Bland-Altman plots showed a mean bias of -4.3% with limits of agreement of 15.7% and -24.3% for TOI and SjO(2) and a mean bias of -4.9% with limits of agreement of 10.3% and -20.1% for TOI and SvO(2). Cerebral rSO(2) and SjO(2) showed a significant correlation (r = 0.83, P < 0.0001) and rSO(2) and SvO(2) showed excellent correlation with r = 0.93 (P < 0.0001). Bland-Altman plots showed a mean bias of -5.2% with limits of agreement of between 8.4% and -18.8% for rSO(2) and SjO(2) and a mean bias of 5.6% with limits of agreement of 13.4% and -2.2% for rSO(2) and SvO(2). CONCLUSIONS: Both near-infrared spectroscopy devices demonstrate a significant correlation with SjO(2) and SvO(2) values; nevertheless both devices demonstrate a substantial bias of the measurements to both SjO(2) and SvO(2).     

控制性低中心静脉压对腹腔镜肝癌切除术患者中心静脉血氧饱和度和乳酸的影响

目的 探讨腹腔镜肝癌切除术中硝酸甘油控制性低中心静脉压（CLCVP）对患者术中中心静脉血氧饱和度（ScvO₂）和动脉血乳酸（Lac）的影响。
方法 选择择期行腹腔镜肝癌切除术患者50例,男27例,女23例,年龄36～64岁,BMI 18~25 kg/m²,ASA Ⅰ或Ⅱ级,采用随机数字表将患者随机分为两组：CLCVP组（L组）和对照组（C组）,每组25例。L组在切肝前5 min通过静脉泵注硝酸甘油0.2～0.5 μg·kg^-1·min^-1,维持CVP≤5 cmH₂O;C组常规输液并维持CVP 6～12 cmH₂O。记录术中出血量、输液量和苏醒时间,记录切肝前15 min、切肝中10、40 min、切肝后30 min的ScvO₂、Lac、HR和MAP。记录术后不良反应的发生情况。
结果 与C组比较,L组术中出血量和输液量明显降低（P＜0.05）。与切肝前15 min比较,切肝中10、40 min,L组ScvO₂和MAP明显降低（P＜0.05）;切肝中10 min,L组HR明显增快（P＜0.05）。与C组比较,切肝中10、40 min,L组ScvO₂和MAP明显降低（P＜0.05）。两组苏醒时间、术后不良反应发生率差异无统计学意义。
结论 腹腔镜肝切除术中硝酸甘油CLCVP可有效减少术中出血,使ScvO₂下降,对Lac值无明显影响,且不增加不良反应。     

Infusion rate of propofol and jugular venous oxygen saturation

We compared jugular venous blood oxygen saturation (Sj(O) (2)) and the arterial-to-jugular-bulb venous oxygen content difference (AjD(O) (2)) between bispectral index (BIS) values of 40 and 60, adjusted by the infusion rate of propofol. Eighteen postoperative neurosurgical patients (Glasgow Coma Scale [GCS] scores, 11-15) were enrolled. Normocapnia, normothermia, and a mean arterial blood pressure greater than 70 mmHg were maintained. At BIS values of 40 and 60, hemoglobin, oxygen saturation, and the oxygen partial pressure of arterial and jugular venous blood were measured. Sj(O) (2) at BIS40 (58 +/- 9%) was significantly (P < 0.01) lower than that at BIS60 (63 +/- 10%), and AjD(O) (2) at BIS40 (6.3 +/- 1.5 ml.dl(-1)) was significantly (P < 0.01) higher than that at BIS60 (5.7 +/- 1.5 ml.dl(-1); mean +/- SD). At BIS40, status defined as Sj(O) (2) less than 50% was observed in 3 patients, while this status was observed in 1 patient at BIS60. In conclusion, in patients with postoperative neurosurgical surgery (GCS scores, 11-15), decreases of propofol infusion to adjust the BIS value from 40 to 60 increase the cerebral oxygen balance.     

Continuous monitoring of jugular bulb oxygen saturation in comatose patients — Therapeutic implications

Summary Comatose patients run a high risk of developing cerebral ischaemia which may considerably influence final outcome. It would therefore be extremely useful if one could monitor cerebral blood flow in these patients. Since there is a close correlation between the arteriovenous difference of oxygen and cerebral blood flow, it was a logical step to place a fiberoptic catheter in the jugular bulb for continuous measurement of cerebrovenous oxygen saturation.We have monitored cerebral oxygenation in 54 patients, comatose because of severe head injury, intracerebral haemorrhage or subarachnoid haemorrhage.Normal jugular venous oxygen saturation (SJVO₂) ranges between 60 and 90%. A decline to below 50% is considered indicative of cerebral ischaemia. Spontaneous episodes of desaturation (SJVO₂<50% for at least 15 min) were frequent during the acute phase of these insults. Many of these desaturation episodes could be attributed to hyperventilation, even though considered moderate. Likewise, insufficient cerebral perfusion pressure and severe vasospasm were found to be important causes of desaturation episodes. In many instances, tailoring of ventilation or induced hypervolaemia and hypertension were capable of reversing these low flow states.The new method of continuous cerebrovenous oximetry is expected to contribute to a better outcome by enabling timely detection and treatment of insufficient cerebral perfusion.     

无创心排量联合中心静脉血氧饱和度监测对急性返流性胆管炎合并休克早期目标导向性液体复苏的指导作用

目的 探讨无创心排量（cardiac output,CO）联合中心静脉血氧饱和度（central venous oxygen saturation,ScvO₂）监测对急性返流性胆管炎合并休克早期目标导向性液体复苏的指导作用。方法 回顾性分析广州市花都区人民医院肝胆胰外科2015年1月至2019年12月间收治的94例急性返流性胆管炎合并休克患者资料,分为研究组和对照组两组,每组各47例。在指导早期液体复苏的治疗中,对照组监测患者平均动脉压（MAP）及中心静脉压（CVP）完成,研究组通过床旁多普勒无创血流动力学检测仪动态监测患者CO及经中心静脉导管监测患者ScvO₂。比较两组早期容量达标时间、24 h后休克指数变化、治疗后6 h血乳酸清除率,治疗前及治疗后第3、7天APACHE-III评分的变化情况,治疗后并发症发生率和病死率。结果 研究组早期容量达标时间较对照组明显缩短,24 h后休克指数较对照组明显降低,治疗后6 h血乳酸清除率明显高于对照组,且第3、7天的APACHE-III评分较对照组降低（均P＜0.05）;研究组治疗后并发的肝脓肿、肺部感染、急性肾功能衰竭及消化道出血发生率明显低于对照组（P＜0.01）,而脓毒血症发生率及病死率两组无明显差别（P＞0.05）。结论 临床上联合无创心排量和中心静脉血氧饱和度监测对急性返流性胆管炎合并休克患者早期液体管理具有良好指导作用,值得临床推广。     

Lower limits of hematocrit and mixed venous oxygen saturation ensuring sufficient cerebral oxygenation during hemodilution in rabbits

Objectives: We have assessed clinically systemic tissue oxygenation by monitoring mixed venous oxygen saturation (SvO₂) in addition to hematocrit (Hct) during cardiopulmonary bypass. Based on results of experimental studies together with clinical experience, we previously defined the lower limits of the critical range as an Hct of 12% and an SvO₂ of 46%. However, these values do not provide direct information about cerebral oxygenation. This study was performed to identify critical values for these variables that would be able to ensure sufficient jugular venous oxygen saturation (SjO₂), which reflects global cerebral oxygenation. Methods: Normovolemic hemodilution was performed in ten rabbits. Hct, SvO₂ and SjO₂ were measured every 7 minutes. The safety limit for cerebral oxygenation was defined as an SjO₂ of 50% based on studies of Croughwell et al. and Cook et al. The limit point was defined as 7 minutes before the time that the SjO₂ decreased below 50% for the first time. Results: Minimal values for Hct and SvO₂ to maintain SjO₂ at 50% or more during normovolemic normothermic hemodilution, expressed as the 95% confidence interval, were Hct of 7.4% to 10.0% and SvO₂ of 41.8% to 51.4%. Conclusion: Adopting the higher values of these pairs, safety limits for cerebral oxygenation would be an Hct of 10.0% and an SvO₂ of 51.4%. In conclusion, our experiments in rabbits suggest new safety limits during normovolemic normothermic hemodilution of Hct of 12% and SvO₂ of 52%, taking both whole-body and cerebral oxygenation into consideration.     

Ultrasound-guided central venous cannulation in infants and children

BACKGROUND: Percutaneous central venous cannulation in infants and children is a challenging procedure. Traditionally, an external landmark technique has been used to identify puncture site. An ultrasound-guided technique is now available and we wanted to evaluate this method in children and infants, looking specifically at the ease of use, success rate and complications. METHODS: Forty-two consecutive infants and children (median 16.5 [0-177] months and 10 [3-45] kg) scheduled for central venous catheter placement were registered. An ultrasound scanner made for guiding puncture of vessels was used. After locating the puncture site, a sterile procedure was performed using an accompanying kit to aid puncture of the vessel. RESULTS: Cannulation was successful in all patients and we had no complications during insertion of the catheters. The right internal jugular vein was preferred in most patients, and in 95% of the patients the vein was punctured at the first attempt. The median time from start of puncture to aspiration of blood was 12 (3-180) seconds. CONCLUSION: The ultrasound-guided technique for placement of central venous catheters was easy to apply in infants and children. It is our impression that it increased the precision and safety of the procedure in this group of patients.     

Comparison of the flow rates of central venous catheters designed for rapid transfusion in infants and small children

Large-bore Hickman® catheters are useful in infants and small children for the rapid transfusion of blood or fluids into the central circulation. Recently high-flow plastic sheaths have been developed for the same purpose. We compared the flow rates of normal saline, 5% albumin and packed red blood cells through two sizes of Hickman catheters that have been recommended for major surgery in infants to five sizes of Arrow® plastic sheaths of comparable external diameters, and to 14 and 16 gauge Jelco® catheters. The flow rates of all three solutions through the plastic sheaths and the 14 gauge Jelco catheters were superior to both sizes of Hickman catheters. Shortening the Hickman catheters improved their flow. High-flow plastic sheaths can provide a useful alternative to Hickman catheters in patients where permanent, large-bore central venous catheters are not required. Hickman catheters should be shortened as much as safely possible if massive haemorrhage is anticipated.     

Early warning for SpO2 decrease by the oxygen reserve index in neonates and small infants

Introduction

Continuously assessing the oxygenation levels of patients to detect and prevent hypoxemia can be advantageous for safe anesthesia, especially in neonates and small infants. The oxygen reserve index (ORI) is a new parameter that can assess oxygenation through a relationship with arterial oxygen partial pressure (PaO₂). The aim of this study was to examine whether the ORI provides a clinically relevant warning time for an impending SpO₂ (pulse oximetry hemoglobin saturation) reduction in neonates and small infants.

Methods

ORI and SpO₂ were measured continuously in infants aged <2 years during general anesthesia. The warning time and sensitivity of different ORI alarms for detecting impending SpO₂ decrease were calculated. Subsequently, the agreement of the ORI and PaO₂ with blood gas analyses was assessed.

Results

The ORI of 100 small infants and neonates with a median age of 9 months (min–max, 0–21 months) and weight of 8.35 kg (min–max, 2–13 kg) were measured. For the ORI/PaO₂ correlation, 54 blood gas analyses were performed. The warning time and sensitivity of the preset ORI alarm during the entire duration of anesthesia were 84 s (25th–75th percentile, 56–102 s) and 55% (95% CI 52%–58%), and those during anesthesia induction were 63 s (40–82 s) and 56% (44%–68%), respectively. The positive predictive value of the preset ORI alarm were 18% (95% CI 17%–20%; entire duration of anesthesia) and 27% (95% CI 21%–35%; during anesthesia induction). The agreement of PaO₂ intervals with the ORI intervals was poor, with a kappa of 0.00 (95% CI = [−0.18; 0.18]). The weight (p = .0129) and height (p = .0376) of the infants and neonates were correlated to the correct classification of the PaO₂ interval with the ORI interval.

Conclusions

The ORI provided an early warning time for detecting an impending SpO₂ decrease in small infants and neonates in the defined interval in this study. However, the sensitivity of ORI to forewarn a SpO₂ decrease and the agreement of the ORI with PaO₂ intervals in this real-life scenario were too poor to recommend the ORI as a useful early warning indicator for this age group.     

Central and mixed venous blood oxygen correlate well during acute normovolemic hemodilution in anesthetized pigs

Background : Central venous oxygen saturation (S_cvO₂) and oxygen tension (p_cvO₂), obtained from the superior vena cava, correlate well with mixed venous (pulmonary arterial) oxygen saturation (S_vO₂) and tension (p_vO₂) when the hematocrit is normal. The present study was undertaken to assess whether extreme hemodilution affects this relation. Methods : We compared mixed and central venous blood during graded arterial desaturation (inspired fraction of oxygen (F_IO₂) between 1.0 and 0.10) in 10 hemodiluted pigs, and in 10 pigs with normal hematocrit (control), during fentanyl-ketamine-pancuronium anesthesia and mechanical ventilation. Results : Arterial oxygen saturation decreased from 100% at F_IO₂=1.0 to 44 ± 12% at F_IO₂=0.10 (mean ± SD). Venous oxygen saturation ranged from 3.5% to 97.3%. The regression coefficient between S_vO₂ and S_cvO₂ was 0.97 (R²= 0.93, bias -2.4 ± 5.8%) in the hemodiluted and 0.99 (R²= 0.97, bias -3.0 ± 5.0%) in the control group. Venous oxygen tension values ranged from 0.5 kPa to 9.5 kPa, and the regression coefficient for oxygen tension was 0.94 (R²= 0.89, bias -0.20 ± 0.47 kPa) in the hemodiluted and 0.99 (R²= 0.97, bias -0.43 ± 0.48 kPa) in the control group. The regression coefficient for pH was 0.95 in the hemodiluted and 0.98 in the control animals. Conclusion : The findings indicate that also during hemodilution monitoring of central venous blood oxygen may be as useful as monitoring of mixed venous blood oxygen.     

Correlation between Glasgow coma scale and Jugular venous oxygen saturation in severe traumatic brain injury

BackgroundGlasgow Coma Scale (GCS) remains a key measure in neurological assessment after head injury and in most studies classification of the severity of the trauma is still based on the admission GCS.The aim of the workThe aim of the work was to correlate between Jugular venous oxygen saturation (Sjvo2) with GCS in cases with severe traumatic brain injury.Patients and methodsA 44 patients met the inclusion criteria, were included in the present study. They were selected from the neurosurgical and intensive care units at Al-Azhar University hospital during the period from June 2010 till June 2012. All therapeutic interventions were performed in accordance with Guidelines for the Management of Severe Traumatic Brain Injury. The following variables were collected: patients’ demographics, Sjvo2, ICP, MAP, CPP and GCS. All pressures were monitored invasively and with identical transducers connected to monitors, and expressed numerically in mmHg. Measurements were always performed at 8.00 a.m. At the same time, patients were neurologically examined and these data were expressed as GCS score.ResultsThere was statistically significant increase of GCS, MAP, CPP, Sjvo2 and Extended Glasgow Outcome Scale (GOSE) and decrease of ICP in survived in comparison to non-survived cases. In survived cases, there was positive significant correlation between Sjvo2 and GCS, MAP, CPP and GOSE, while there was significant negative correlation with ICT. On the other hand, in non-survived cases, there was only positive moderate, significant correlation between Sjvo2 and GCS. Running simple linear regression analysis, only GCS and Sjvo2 can predict mortality in studied cases.ConclusionResults of the present study proved that, Sjvo2 is proportionally correlated with GCS and both can predict the prognosis of severe traumatic injury.     

An audit of induction of anaesthesia in neonates and small infants using pulse oximetry

The frequency and severity of hypoxaemia during induction of anaesthesia in neonates and small infants at the Norfolk and Norwich Hospital, a district general hospital, was compared, using pulse oximetry, with that of the nearest specialist hospital, the Queen Elizabeth Hospital for Sick Children in London. There were differences in staffing and the choice of anaesthetic techniques between the hospitals. One third of the patients in both hospitals experienced desaturation of more than 5% (moderate or severe hypoxaemia) at one or more recordings during induction. The highest incidence of hypoxaemia was associated with awake intubation. There was no statistical difference in the incidence or severity of hypoxaemia between the hospitals. In the district general hospital, moderate or severe hypoxaemia of greater than 30 s duration was more likely if an anaesthetist with a regular paediatric operating list was not present at induction (p < 0.01).