Continuous monitoring of central venous oxygen saturation in neonates and small infants: in vitro evaluation of two different oximetry catheters

BACKGROUND: Accurate assessment and monitoring of the cardiocirculatory function are essential during major pediatric and pediatric cardiac surgery. Monitoring of the central venous oxygen saturation (ScvO(2)) may be a better indicator of tissue oxygenation and derangement of cellular oxygen utilization than the more commonly used vital parameters. Therefore, we compared oxygen saturation measurements with thin fiberoptic oximetry catheters and standard blood gas oximetry in an in vitro setting. METHODS: Two different size continuous fiberoptic oximetry catheters (2-4-F) were inserted in an extracorporeal circuit filled with human red blood cells in normal saline (haematocrit 30%, flow 600 ml.min(-1)). The results of fiberoptic oximetry were then compared with standard blood gas oximetry for a wide range of different oxygen saturations using linear regression. RESULTS: The oxygen saturations found ranged from 9% to 100%. The results of the two different fiberoptic oximetry catheters correlated significantly (r = 0.99, P < 0.0001) with standard blood gas oximetry. CONCLUSION: The results of fiberoptic oximetry are nearly identical with standard blood gas oximetry for a wide range of different oxygen saturations. Thin oximetry catheters can be inserted percutaneously even in neonates and small infants. The continuous monitoring of ScvO(2) may be beneficial, especially in patients who are in danger of developing low cardiac output or sudden cardiovascular collapse.     

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.     

Assessment of central venous physiology of Fontan circulation using peripheral venous pressure

Objective

Elevated central venous pressure is a major cause of morbidity and mortality after the Fontan operation. The difference between mean circulatory filling pressure and central venous pressure, a driving force of venous return, is important in determining dynamic changes in central venous pressure in response to changes in ventricular properties or loading conditions. Thus, noninvasive central venous pressure and mean circulatory filling pressure estimation may contribute to optimal management in patients undergoing the Fontan operation. We tested the hypothesis that central venous pressure and mean circulatory filling pressure in those undergoing the Fontan operation can be simply estimated using peripheral venous pressure and arm equilibrium pressure, respectively.

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).     

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。     

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.     

心脏术后早期混合静脉血氧饱和度水平的临床研究

目的研究心脏术后早期混合静脉血氧饱和度（SvO2）水平与围术期因素、术后并发症的关系.方法记录95例心脏手术患者术后12 h内的每小时SvO2、心指数（CI）.按SvO2均数分为＜60%（Ⅰ组,n=10）、60%～70%（Ⅱ组,n=45）、＞70%（Ⅲ组,n=40）三组.统计各组患者年龄、术前左室射血分数（LVEF）、体外循环时间、主动脉阻断时间（ACT）、ICU停留时间、术前基础疾病和在院期间并发症发生数.结果各组间年龄、LVEF、基础疾病发生数无显著性差异.Ⅰ组的ACT、体外循环时间、ICU停留时间较Ⅱ、Ⅲ组显著延长,CI降低,循环及呼吸系统并发症发生率升高（P＜0.05）.结论某些围术期因素可降低心脏术后早期SvO2水平.SvO2水平低时增加并发症的发生率,延长ICU停留时间.     

Cerebral NIRS as a marker of superior vena cava oxygen saturation in neonates with congenital heart disease

Objectives: To investigate the correlation between cerebral near‐infrared spectroscopy (NIRS) (rSO2c) and superior vena cava venous oxygen saturation (ScvO2) in newborn patients with congenital heart disease (CHD). Background: NIRS is a noninvasive method to monitor hemoglobin oxygen saturation using nonpulsatile oximetry. Methods: We retrospectively analyzed perioperative data from 100 newborn patients who underwent cardiac surgery for CHD. rSO2c, ScvO2 from 24 h before to 72 h after surgery were recorded. Results: rSO2c had a fair correlation with ScvO2 (r 0.37; P <0.001). The relationship between rSO2c and ScvO2 did not change when analyzed between patients with cyanotic or acyanotic CHD. During the preoperative period, rSO2c levels overestimated ScvO2; in the first 18 postoperative hours, rSO2c underestimated ScvO2; after that period, they showed very close trends. Hypocapnia caused rSO2c to underestimate ScvO2; in normocapnic patients, rSO2c–ScvO2 average differences were close to zero; in hypercapnic neonates, rSO2c tended to overestimate ScvO2. The best performance of rSO2c as a surrogate of ScvO2 was found in the venous saturation ranges from 40% to 60% (r 0.3, P: 0.03). Conclusions: rSO2c in newborn patients with cyanotic and acyanotic CHD provides a continuous noninvasive information with a fair correlation with ScvO2%: some predictable variables (i.e., time from surgery, carbon dioxide, and venous saturation levels), should guide the operators to adjust rSO2c values in terms of ScvO2. Serial measures of ScvO2 seem recommended to tailor rSO2c information on actual venous saturation percentage.     

The development of a control method for a total artificial heart using mixed venous oxygen saturation

For physiological control of a total artificial heart (TAH), applying mixed venous oxygen saturation (SVO2) as a parameter for TAH control is a promising approach regarding sensitivity to the recipient's oxygen demand and the practical possibility of continuous monitoring using near infrared rays through transparent blood pump housings. To develop a control method for the TAH using SVO2, the relationship between SVO2 and cardiac output (CO) was investigated in a normal calf, and a control algorithm was developed based on this correlation. Then the feasibility of this method (SVO2 mode) was evaluated in a calf implanted with a pneumatic TAH and compared with the fixed drive control mode (fixed mode) in which the drive parameters were unchanged. The calf performed a graded exercise test in both modes. The CO was effectively increased from 7.3 to 13.0 L/min in the SVO2 mode, and the capacity for exercise was augmented compared to the fixed mode. We conclude that this SVO2 mode is feasible and may be effectively applied in TAH control.     

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.     

肝移植术中应用控制性低中心静脉压技术对脑氧代谢的影响

目的 观察肝移植术中应用控制性低中心静脉压(CLCVP)技术对脑氧代谢的影响,探讨肝移植术中应用CLCVP技术的安全性.方法 选择因终末期肝病接受肝移植的受者46例,将受者分为CLCVP组(CL组,23例)和正常中心静脉压(CVP)组(C组,23例),于手术开始前即刻(T1)、下腔和门脉阻断前即刻(T2)、无肝期30 min时(T3)、新肝期30 min时(T4)、新肝期2h时(T5)、新肝期24 h时(T6),采集受者桡动脉和颈静脉血行血气分析,并计算动脉血氧含量(CaO2)、颈静脉血氧含量(QjvO2)、动脉-颈静脉血氧含量差(Ca-jvO2)、颈静脉血氧饱和度(SjvO2)、脑氧摄取率(CE-RO2)及脑血流/脑氧代谢比值(CBF/CMRO2)等指标.同时检测两组受者的血肌酐和尿素氮水平,并记录手术耗时、无肝期时间、红细胞和血浆输入量、输液总量、出血量及尿量等指标.结果 T1、T2、T3、T4、T5及T6各时点,两组间CaO2、CjvO2、Ca-jvO、SjvO2、CERO、CBF/CMRO2的差异无统计学意义(P＞0.05);两组T3、T4、T5时CaO2、CjvO2、Ca-jvO2、CERO2均较T1和T2时显著降低(P＜0.05),而SjvO2较T1和T2时显著增高(P＜0.05),T6时两组间和组内的差异均无统计学意义(P＞0.05).两组受者手术耗时和无肝期时间均无显著差异(P＞0.05).CL组术中出血量、红细胞和血浆输入量、输液总量均明显低于C组(P＜0.05),CL组术中尿量较C组显著增加(P＜0.05),两组间和组内血肌酐和尿素氮的差异均无统计学意义.结论 肝移植术中应用CLCVP技术对脑氧代谢无不良影响,同时可显著减少术中出血量,增加术中尿量.     

The accuracy of a fiberoptic oximeter over a wide range of arterial oxygen saturation values in piglets

A piglet model was used to evaluate the accuracy of a fiberoptic oximeter over a wide range of arterial oxygen saturation (SaO₂) values. In eight anaesthetized piglets, the inspired oxygen concentration was varied from 30% to 6% resulting in a SaO₂ range from 100% to 15%. Paired data of the Opticath® fiberoptic catheter, which was placed in the descending aorta, and blood sample SaO₂ values assessed by a multiwavelength oximeter, were analysed. After in vitro calibration according to the manufacturer's instruction, the fiberoptic catheter started to underestimate the SaO₂ below 78%, worsening towards lower SaO₂ values. The overall bias was -3. 4% and the precision 3. 8%. An off-line fit with a non-linear model resulted in a standard deviation of residuals of 2. 6%. After several in vivo calibration adjustments when the Fiberoptic oximeter deviated more than 4% from the blood sample value, the bias was eliminated over the total SaO₂ range and the precision was 3. 7%. The Opticath® fiberoptic oximeter could have an accuracy for the whole SaO₂ range between 15–100% close to the accuracy of the multiwavelength oximeter, when the fiberoptic oximeter is adapted for the underestimation below 78% SaO₂.     

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.     

Central venous pressure and pulmonary artery pressure monitoring

Central venous pressure and pulmonary artery pressure are used as measures of cardiovascular filling. While pressure–volume relationships are not constant, trends in central venous pressure give an indication of increasing or decreasing right ventricular filling, while pulmonary artery pressure gives an indirect indication of left ventricular filling pressure. Cardiac output can be estimated by use of thermodilution.     

不同输液速度对中心静脉压测量值的影响

目的探讨不同输液速度对中心静脉压(CVP)测量值的影响。方法将59例深静脉置管患者分别在常规中断输液(对照组)和以50mL/h(观察1组)、100mL/h(观察2组)、200mL/h(观察3组)、300mL/h(观察4组)速度连续输液5min后监测并记录CVP。结果五组CVP监测值比较,差异无统计学意义(P>0.05)。结论深静脉置管输入普通液体的患者,输液速度在300mL/h以内对中心静脉压测量值无显著影响。