Feasibility of using head up patient position in maintaining low central venous pressure and restricting the need for pharmacological agents during major hepatectomy.

Paucity of data meant that we could not assess transitivity assumptions and inconsistency for most analyses. When direct and indirect comparisons were available, network meta-analysis provided additional effect estimates for comparisons where there were no direct comparisons. However, the paucity of data decreases the confidence in the results of the network meta-analysis. Low-quality evidence suggests that liver resection using a radiofrequency dissecting sealer may be associated with more adverse events than with the clamp-crush method. Low-quality evidence also suggests that the proportion of people requiring a blood transfusion is higher with low central venous pressure than with acute normovolemic haemodilution plus low central venous pressure; very low-quality evidence suggests that blood transfusion quantity (red blood cells) was lower with fibrin sealant than control; blood transfusion quantity (fresh frozen plasma) was higher with oxidised cellulose than with fibrin sealant; and blood loss, total hospital stay, and operating time were lower with low central venous pressure than with control. There is no evidence to suggest that using special equipment for liver resection is of any benefit in decreasing the mortality, morbidity, or blood transfusion requirements (very low-quality evidence). Radiofrequency dissecting sealer should not be used outside the clinical trial setting since there is low-quality evidence for increased harm without any evidence of benefits. In addition, it should be noted that the sample size was small and the credible intervals were wide, and we cannot rule out considerable benefit or harm with a specific method of liver resection.

The Use of Internal Jugular Vein Ultrasonography to Anticipate Low or High Central Venous Pressure During Mechanical Ventilation

Application of controlled low central venous pressure (LCVP) in liver resection growing in popularity, but its efficacy and safety are still controversial. Our objectives were to assess and compare the efficacy, feasibility, and safety of controlled LCVP in patients undergoing liver resection. The PubMed, Cochrane library, and EMBASE databases were systematically searched for all the relevant studies regardless of study design. We evaluated the methodological quality of the included studies and excluded studies of poor quality. Moreover, we applied a systematic review and meta-analysis by using RevMan 5.3 software to compare the efficacy and safety of LCVP vs. standard CVP for liver resection. Outcomes included operation time, blood loss, blood infusion, fluid infusion, urinary volume, postoperative complication rates, and hospital stay. In total, 10 studies, involving 324 patients undergoing liver resection with controlled LCVP, were identified. Meta-analysis displayed that blood loss in the LCVP group was dramatically less than that in the control group (standard CVP group, mean difference (MD): -581.68; 95% CI: -886.32 to -277.05; P=0.0002). Moreover, blood transfusion in the LCVP group was also markedly less than that in the control group (MD: -179.16; 95% CI: -282.00 to -76.33; P=0.0006). However, there was no difference between LCVP group and control group in operation time (MD: -16.24; 95% CI: -39.56 to 7.09; P=0.17), fluid infusion (MD: -287.89; 95% CI: -1,054.47 to 478.69; P=0.46), urinary volume (MD: -26.88; 95% CI: -87.14 to 33.37; P=0.38), ALT (MD: -58.66; 95% CI: -153.81 to 36.50; P=0.23), TBIL (MD: -0.32; 95% CI: -3.93 to 3.28; P=0.86), BUN (MD: -0.13; 95% CI: -0.73 to 0.47; P=0.67), CR (MD: 1.87; 95% CI: -4.90 to 8.63; P=0.59), postoperative complication rates (MD: 0.62; 95% CI: 0.44 to 0.90; P=0.01) and hospital stay (MD: -0.61; 95% CI: -1.68 to 0.46; P=0.26). Compared with the control, controlled LCVP showed comparable efficacy and safety for the treatment during liver resection.

To compare the outcomes of low central venous pressure (CVP) to standard CVP during laparoscopic liver resection. The study design was a systematic review following the PRISMA statement standards. The available literature was searched to identify all studies comparing low CVP with standard CVP in patients undergoing laparoscopic liver resection. The outcomes included intraoperative blood loss (primary outcome), need for blood transfusion, mean arterial pressure, operative time, Pringle time, and total complications. Random- effects modelling was applied for analyses. Type I and type II errors were assessed by trial sequential analysis (TSA). A total of 8 studies including 682 patients were included (low CVP group, 342; standard CVP group, 340). Low CVP reduced intraoperative blood loss during laparoscopic liver resection (mean difference [MD], -193.49 mL; 95% confidence interval [CI], -339.86 to -47.12; p = 0.01). However, low CVP did not have any effect on blood transfusion requirement (odds ratio [OR], 0.54; 95% CI, 0.28-1.03; p = 0.06), mean arterial pressure (MD, -1.55 mm Hg; 95% CI, -3.85-0.75; p = 0.19), Pringle time (MD, -0.99 minutes; 95% CI, -5.82-3.84; p = 0.69), operative time (MD, -16.38 minutes; 95% CI, -36.68-3.39; p = 0.11), or total complications (OR, 1.92; 95% CI, 0.97-3.80; p = 0.06). TSA suggested that the meta-analysis for the primary outcome was not subject to type I or II errors. Low CVP may reduce intraoperative blood loss during laparoscopic liver resection (moderate certainty); however, this may not translate into shorter operative time, shorter Pringle time, or less need for blood transfusion. Randomized controlled trials with larger sample sizes will provide more robust evidence.

To evaluate the effect of low central venous pressure (LCVP) on blood loss and blood transfusion in patients undergoing hepatectomy. Electronic databases and bibliography lists were searched for potential articles. A meta-analysis of all randomized controlled trials (RCTs) investigating LCVP in hepatectomy was performed. The following three outcomes were analyzed: blood loss, blood transfusion and duration of operation. Five RCTs including 283 patients were assessed. Meta-analysis showed that blood loss in the LCVP group was significantly less than that in the control group (MD = -391.95, 95%CI: -559.35--224.56, P < 0.00001). In addition, blood transfusion in the LCVP group was also significantly less than that in the control group (MD = -246.87, 95%CI: -427.06--66.69, P = 0.007). The duration of operation in the LCVP group was significantly shorter than that in the control group (MD = -18.89, 95%CI: -35.18--2.59, P = 0.02). Most studies found no significant difference in renal and liver function between the two groups. Controlled LCVP is a simple and effective technique to reduce blood loss and blood transfusion during liver resection, and appears to have no detrimental effects on liver and renal function.

Objective To investigate the blood-saving effect of controlled low central venous pressure (CLCVP) in different types of hepatectomy.Methods Ninety ASA physical status Ⅰ or Ⅱ patients of both sexes,aged 37-76 yr,weighing 40-75 kg,undergoing elective hepatectomy,were divided into 6 groups according to the surgical approach and whether CLCVP was used during surgery (n =15 each):CLCVP1-3 groups and nonCLCVP1-3 groups (NCLCVP1-3 groups).The standard hepatectomy,half liver resection and irregular hepatectomy were performed in CLCVP1-3 groups,respectively,with CLCVP.The standard hepatectomy,half liver resection and irregular hepatectomy were performed in NCLCVP1-3 groups,respectively,without CLCVP.In CLCVP1-3 groups,from skin incision to the end of liver resection,CVP was maintained ≤ 5 cm H2 O through adjustment of the position,fluid restriction and iv infusion of nitroglycerin,and norepinephrine was infused simultaneously to maintain mean arterial pressure ≥ 60 mm Hg.In NCLCVP1-3 groups CVP was maintained at 6-12 cm H2O.Intraoperative blood loss and blood transfusion were recorded.Results Compared with NCLCVP1-3 groups,intraoperative blood loss was significantly decreased in CLCVP1-3 groups (P ＜ 0.05).Compared with NCLCVP3 group,the amount of blood transfusion was significantly decreased,the constituent ratio of intraoperative blood loss ＜ 200 ml was increased,and the constituent ratio of intraoperative blood loss ＞ 1000 ml was decreased in group CLCVP3 (P ＜ 0.05).Conclusion CLCVP can decrease the intraoperative blood loss and blood transfusion in patients undergoing irregular hepatectomy. Key words: Hypotension, controlled; Central venous pressure; Blood loss, surgical; Blood transfusion; Hepatectomy

The central venous pressure (CVP) has been regarded as an important factor for reducing blood loss and the blood transfusion rate during major hepatectomy, and can be controlled by positive end-expiratory pressure (PEEP) or certain drugs and the optimal positioning of the patient [1–4]. In this issue of Surgery Today, Wang et al. [5] describe the beneficial effects of lowering the CVP for achieving a better postoperative outcome compared with conventional fluid management in deceased donor liver transplantation based on a prospective randomized controlled study. They report that the low CVP group showed (1) less intraoperative blood loss, (2) a decreased need for intraoperative blood transfusion, (3) fewer lung-related complications at 1 month postoperatively, (4) a shorter intubation period and (5) equal patient survival at 1 year after liver transplantation. A previous retrospective study showed intraoperative blood transfusion to be a risk factor for postoperative lung complications [6]. The present study was done in a prospective, randomized manner, which yielded the same results as those seen in the previous retrospective study. The methods used to reduce the CVP in the present study were the use of the Fowler position, fluid restriction and drugs (e.g., nitroglycerin, furosemide and somatostatin). These methods have also been used in previous studies to reduce the intraoperative CVP, and therefore they appear to be valid for this kind of study [2]. Although the results provided in the article were of high importance, lowering the CVP during liver transplantation might still be controversial and may have ambivalent aspects with regard to the lack of a relationship between the early complication rates, including renal, hepatic and pulmonary complications, and the CVP following liver transplantation [7–10]. For example, apart from the reduced pulmonary complication rate, and the lower blood loss and blood transfusion rate, what would be the influence of lowering the CVP on the postoperative care following liver transplantation? If blood product administration during the intensive care period is increased, then the policy to limit CVP during surgery would be in vain. Therefore, the readers will also want to know: How would the perfusion in the organ be affected? How would the lactate level in the blood after LT be affected, not only at the end of surgery but also during the postoperative period? How would the post-transplant blood product requirements be affected? In fact, the period in which the CVP is lowered may be of importance. For example, Feng et al. [7] reported that a low CVP during the pre-anhepatic phase reduced the intraoperative blood loss, protected the liver function and it also had no detrimental effects on the renal function after LT. On the other hand, Cywinski et al. reported that a low CVP during the post-anhepatic phase was not associated with any benefit in terms of immediate postoperative allograft function, graft survival or patient survival [10]. In addition, the cut-off value for CVP monitoring in previous studies varied between 5 and 10 mmHg. We therefore await further reports from other investigators before drawing any definitive conclusions about the above-mentioned issues, since liver transplant surgery, especially partial liver transplantation, is often affected by multiple factors [11]. This comment refers to the article available at doi:10.1007/s00595-012-0419-y.

BackgroundThis prospective randomized controlled study was designed to evaluate the effect of fluid restriction alone versus fluid restriction + low central venous pressure (CVP) on hepatic surgical field bleeding, intraoperative blood loss, and the serum lactate concentration in patients undergoing partial hepatectomy.MethodsOne hundred forty patients undergoing partial hepatectomy with intraoperative portal triad clamping were randomized into a fluid restriction group (Group F) or fluid restriction + low CVP group (Group L). Both groups received limited fluid infusion before the liver lesions were removed. Ephedrine was administered if the systolic blood pressure (SBP) decreased to <90 mmHg for 1 min. When the urine output was <20 ml/h or the SBP was <90 mmHg for 1 min more than three times, an additional 200 ml of crystalline solution was quickly infused within 10 min. In addition to fluid restriction, patients in Group L received continuous nitroglycerin and esmolol infusion to maintain a low CVP. The duration of portal triad clamping, frequency of additional fluid infusion, frequency of ephedrine administration, intraoperative blood loss, extent of liver resection, and bleeding score of the hepatic surgical field were recorded. Arterial blood gas analysis was performed before anesthesia (T1), after liver dissection and immediately before liver resection (T2), 10 min after removal of the liver lesion (T3), and before the patient was discharged from the postanesthesia care unit (T4).ResultsBeing in the fluid restriction Group (Group F) (odds ratio = 5.04) and cirrhosis (odds ratio = 3.28) were risk factors for hepatic surgical field bleeding. Factors contributing to intraoperative blood loss were the operation time, duration of portal triad clamping, and extent of resection. No significant between-group difference was observed for blood loss or blood transfusion. The serum lactate concentration peaked at T3 in both groups.ConclusionsMaintaining a lower CVP during hepatectomy provides an optimal surgical field but has no significant effect on intraoperative blood loss. Moreover, lower CVP does not increase the serum lactate concentration.Trial registration“A comparative study of the effect fluid restriction and low CVP pressure on the oozing of blood in liver wounds and blood lactate in patients undergoing partial hepatectomy” was prospectively registered as a trial (registration number: ChiCTR-INR-17014172, date of registration: 27 December 2017).

Objective To investigate the effects of hepatic pedicle exclusion and low central venous pressure (LCVP) on blood loss in right lobe tumor resection and evaluate its influence on hepatic and renal function. Methods Forty-eight patients with right lobe tumor admitted from December 2006 to June 2008 were randomly allocated to the LCVP group (23 cases) and routine hepatectomy, (control group 25 cases). During the parenchymal transection phase of surgery, CVP < 5 mm Hg ( 1 mm Hg = 0.133 kPa) and SBP ≥90 mm Hg were maintained in the LCVP group by drugs. However, no special management of CVP and SBP was done in control group. The parenchymal transection blood loss, postoperative hospital stay, postoperative hepatic and renal function changes between two groups were compared, and the incidence of comphcation was also observed. Results There were no significant difference in type of hepatectomy, time of vascular clamping, period of operation, postoperative complication rate, postoperative hepatic and renal functions between two groups. Parenchymal transection blood loss in the LCVP group was significantly lower than that in the control group (326.67 ± 109.13 ) ml vs (538.33 ± 177.07 ) ml, (P < 0.01 ). Postoperative hospital stay in the LCVP group was significantly shorter than that in the control group (8.52 ± 1.78) d vs (9.40±1.68) d, (P < 0.05). Conclusions Hepatic pedicle exclusion and LCVP during hepatectomy is safe. It can reduced blood loss during parenchymal transection and decrease postoperative hospital stay. It is no detrimental effect to hepatic or renal function. Key words: Central venous pressure; Liver neoplasms; Hepatectomy

Comparison Between 2 Strategies of Fluid Management on Blood Loss and Transfusion Requirements During Liver Transplantation

Sir, Vascular air embolism (VAE) is a rare and lethal complication of partial hepatectomy with a relative risk of <5%.[1] Even in the absence of intracardiac abnormalities, paradoxical embolism can occur in cirrhotic patients undergoing liver resection because of abnormal arteriovenous communications in the pulmonary circulation.[2] Anaesthetic vigilance along with thorough knowledge of surgical interventions and ensuing physiological perturbations is essential for ensuring patient survival. A 56-year-old female diagnosed with hilar cholangiocarcinoma was posted for extensive right hepatectomy. Clinical examination was normal except for the presence of jaundice with elevated bilirubin and liver enzymes. Anaesthetic technique included general anaesthesia with thoracic epidural block. Electrocardiogram (ECG), oxygen saturation, blood pressure and end-tidal carbon dioxide (ETCO2) were monitored. Left radial artery was cannulated for invasive blood pressure (IBP) monitoring and right internal jugular vein for central venous pressure (CVP), with double lumen 7 Fr central venous catheter (CVC). To reduce the blood loss and transfusion requirements, a low CVP (≈5 mmHg) was targeted. Hepatic resection using cavitron ultrasonic surgical aspirator (CUSA) began after clamping the branches of portal vein and hepatic artery to the right lobe. Three hours into the surgery, surgeon informed accidental opening of a branch of hepatic vein which got retracted into liver parenchyma. Simultaneously, a distinct sucking-in sound was heard, following which IBP dropped to 50/40 mmHg and ETCO2 to 22 mmHg from 34 mmHg while oxygen saturation and CVP (8 mmHg) remained stable. VAE was suspected and nitrous oxide was cut off and the patient ventilated with 100% oxygen. Surgical field was immediately covered with saline-soaked gauze, and then flooded with saline. Resuscitative measures were initiated rapidly with fluid resuscitation, dopamine infusion at 10μg/kg/min and adopting a Trendelenburg position. Aspiration of CVC produced 3 ml of frothy blood. As IBP remained low, epidural infusion was discontinued and a bolus of 50μg adrenaline was administered intravenously. Once vitals stabilised, surgery proceeded with 100% oxygen after giving fentanyl and midazolam. Fifteen minutes later, a second episode of VAE occurred and was accompanied by a fall in oxygen saturation, IBP, ETCO2 and a rise in CVP to 18 mmHg. ECG showed frequent atrial ectopic beats. Dopamine infusion rate was increased and CVC aspirated to obtain 3–4 ml of air. Two more episodes of haemodynamic instability occurred which was treated similarly. At the end of the procedure, her vitals were stable with dopamine support. She was shifted to intensive care unit and was weaned from haemodynamic and ventilator support next day. Factors predisposing to VAE during liver resection include surgical technique, size and site of the tumour, blood loss and low CVP.[3] There are reports of increased incidence and severity of VAE during hepatic resection using CUSA.[4,5] Resection of large tumours situated in the right lobe close to inferior vena cava or the cavo-hepatic junction increases the risk of VAE.[3] Low CVP further enhances the negative pressure gradient and increases the possibility of VAE. Hepatic vascular control using selective hepatic vascular exclusion (SHVE) technique reduces both blood loss and risk of VAE.[3] In our case, site of the tumour, resection using CUSA and lack of SHVE technique along with low CVP anaesthesia all contributed to the incident. Although lethal volume of venous air for adults is about 200–300 ml, the proximity of the entraining vessel to the heart makes even smaller volumes fatal in liver resection.[1,3] Management consists of steps to prevent further entrainment of air and haemodynamic support with inotropic agents.[1,2,3,4] To conclude, both surgeons and anaesthesiologists should be aware of the risk for VAE during hepatectomy and employ appropriate surgical techniques and levels of monitoring to ensure patient safety. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Goal-directed fluid therapy versus low central venous pressure strategy during major liver resections (GALILEO): A patient- and surgeon-blinded randomized controlled trial

BACKGROUNDː Lowering central venous pressure (CVP) can decrease blood loss during liver resection and it is associated with improved outcomes. Multiple CVP reducing maneuvers have been described, but direct comparison of their effectiveness and safety has never been performed. METHODSː Patients undergoing resections of two or more liver segments were equally randomized to absolute fluid restriction (AR, N.=17) or relative volume redistribution group (RR, N.=17). The ease of reaching low CVP, blood loss, morbidity and mortality were assessed. Besides, the effect of Pringle maneuver and utility of stroke volume variation (SVV) were analyzed. RESULTSː Both methods of CVP reduction were equally effective (0.7±0.9 vs. 0.9±1.0 protocolized steps in the AR and RR group; P=0.356) and safe (no difference in observed blood loss, intraoperative hemodynamic parameters, lactate levels, morbidity and mortality). Patients in the AR group received smaller amount of fluids in the pre-resection period (120 (100-150) vs. 600 (500-700) mL; P<0.001), and had slightly longer hospital stay (10 [8-14] vs. 8 [7-11]; P=0.045). Low CVP was predicted by SVV>10% with 81.4% sensitivity and 77.1% specificity. Reduced blood loss and transfusion rate was observed when Pringle maneuver was used. CONCLUSIONSː In our study, absolute fluid restriction and relative volume redistribution seemed to be equally effective and safe methods of lowering CVP in patients undergoing liver resection. According to our data high SVV might be considered as a low CVP replacement. Pringle maneuver reduced blood loss and transfusion requirement.

A commentary on “Milrinone is better choice for controlled low central venous pressure during hepatectomy: A randomized, controlled trial comparing with nitroglycerin” [Int. J. Surg. (2021) 94: 106080

Objective:To compare acute normovolemic hemodilution versus low central venous pressure strategy versus conventional fluid management in reducing intraoperative estimated blood loss, hematocrit drop and need for blood transfusion in patients undergoing radical retropubic prostatectomy under general anesthesia.Research design and methods:Patients undergoing radical retropubic prostatectomy under general anesthesia were randomized to conventional fluid management, acute normovolemic hemodilution or low central venous pressure (≤5 mmHg). Treatment effects on estimated blood loss and hematocrit change were tested in multivariable regression models accounting for surgeon, prostate size, and all two-way interactions.Results:Ninety-two patients completed the study. Estimated blood loss (mean ± SD) was significantly lower with low central venous pressure (706 ± 362 ml) compared to acute normovolemic hemodilution (1103 ± 635 ml) and conventional (1051 ± 714 ml) groups (p = 0.0134). There was no difference between the groups in need for blood transfusion, or hematocrit drop from preoperative values. The multivariate model predicting estimated blood loss showed a significant effect of treatment (p = 0.0028) and prostate size (p = 0.0323), accounting for surgeon (p = 0.0013). In the model predicting hematocrit change, accounting for surgeon difference (p = 0.0037), the treatment effect depended on prostate size (p = 0.0007) with the slope of low central venous pressure differing from the other two groups. Hematocrit was predicted to drop more with increased prostate size in acute normovolemic hemodilution and conventional groups but not with low central venous pressure.Key limitations:Limitations include the inability to blind providers to group assignment, possible variability between providers in estimation of blood loss, and the relatively small sample size that was not powered to detect differences between the groups in need for blood transfusion.Conclusions:Maintaining low central venous pressure reduced estimated blood loss compared to conventional fluid management and acute normovolemic hemodilution in patients undergoing radical retropubic prostatectomy but there was no difference in allogeneic blood transfusion between the groups.