Transurethral endoscopic procedures using bipolar current, or laser energy are nowadays widely accepted and have replaced the traditional monopolar resection. A major advantage of these techniques is the utilization of isotonic saline as irrigation solution, which minimizes side effects such as symptoms associated to classical transurethral resection syndrome (TUR-syndrome). Nonetheless, clinically significant IFA also occurs with saline and is determined by pressure gradients, systemic resistance and by the amount of irrigation fluid. We aimed to investigate the extend of IFA and symptoms due to volume overload during bipolar transurethral resection (bTUR) and laser procedures of the prostate.‍

使用双极电流或激光能量的经尿道内窥镜手术已被广泛接受取代了传统的单极切除。这些技术的一个主要优点是利用等渗盐水灌洗液，最大限度地减少副作用，如与经典经尿道切除术综合征相关的症状(TUR-syndrome)。但生理盐水也会发生IFA，由压力梯度、系统阻力和由灌注液体量决定。本研究的目的是对双极经尿道前列腺电切术(bTUR)和前列腺激光手术时IFA导致的容量超负荷导致相关症状和机制进行进一步探索。

We performed a systematic literature search using PubMed, restricted to original English-written articles, including animal, artificial model, and human studies. Search terms were TUR, transurethral, laser, HoLEP, ThuLEP, greenlight, enucleation, fluid absorption, fluid uptake, and TUR-syndrome.We performed a systematic literature search using PubMed, restricted to original English-written articles, including animal, artificial model, and human studies. Search terms were TUR, transurethral, laser, HoLEP, ThuLEP, greenlight, enucleation, fluid absorption, fluid uptake, and TUR-syndrome.

我们使用PubMed进行了系统的文献检索，仅限于原始英文文章，包括动物、人工模型和人类研究。搜索词为:TUR, transurethral, laser, HoLEP, ThuLEP, greenlight, enucleation, fluid absorption, fluid uptake, and TUR-syndrome。我们使用PubMed进行了系统的文献检索，仅限于原始英文文章，包括动物、人工模型和人类研究。搜索词为:TUR, transurethral, laser, HoLEP, ThuLEP, greenlight, enucleation, fluid absorption, fluid uptake, and TUR-syndrome。

Mean and maximum IFA during bTURP ranges between 133 and 915 ml and 1019 ml and 2166 ml, respectively. Absorption during laser procedures can be significant with maximum values up to 4579 ml and mainly occurs during prostate

vaporization techniques. Incidence of moderate to severe symptoms from iso-osmolar volume overload reaches 9%.

bTURP期间的平均和最大IFA分别在133和915 ml、1019 ml和2166 ml之间。激光治疗过程中可导致大量IFA，最大值可达4579ml，主要发生在前列腺汽化过程。等渗容量超负荷的中至重度症状发生率达9%。

We performed a systematic literature search using PubMed, restricted to original English-written articles, including animal, artificial model, and human studies. Search terms were TUR, transurethral, laser, HoLEP, ThuLEP, greenlight, enucleation, fluid absorption, fluid uptake, and TUR-syndrome.

我们使用PubMed进行了系统的文献检索，仅限于原始英文文章，包括动物、人工模型和人类研究。搜索词为:TUR, transurethral, laser, HoLEP, ThuLEP, greenlight, enucleation, fluid absorption, fluid uptake, and TUR-syndrome。

Irrigation fluid absorption during bTUR and laser surgery of the prostate is not negligible. Iso-osmolar overhydration with development of non-classical TUR-syndrome should be identified peri-and postoperatively and surgical teams should be aware of complications. Breath ethanol, venous pH, serum chloride, and bicarbonate could be markers for detecting dangerous events of IFA with saline.

在前列腺电切术和激光手术中，前列腺的冲洗吸收是不可忽视的。应在围手术期和术后警惕非经典TURS的等渗性容量负荷增加，手术团队应注意并发症。呼吸乙醇、静脉pH值、血清氯和碳酸氢盐可作为检测生理盐水作用下IFA危险事件的标记物。

Transurethral surgery constitutes an essential field in everyday urology and has been changing fundamentally over the last decades. Bipolar transurethral resection (bTUR) and transurethral laser vaporization, vapo-resection, and enucleation of the prostate are nowadays established surgical methods. Especially, laser technologies achieve favorable results with less bleeding.

经尿道手术是泌尿外科的一个重要领域，在过去的几十年已经发生了根本的变革。双极经尿道前列腺电切术(bTUR)、经尿道激光汽化术、汽化切除术和前列腺切除术是目前较为成熟的手术方法。特别是激光技术取得了良好的效果，出血较少。

Since the introduction of monopolar TUR-P (mTURP), the so-called transurethral resection syndrome (TUR-syndrome), has been a feared complication. TUR-syndrome usually complicates an irrigation fluid absorption (IFA) of >1000 mL, with acute symptoms appearing at IFAs of >2500 mL. Over the years, surgeons became more aware of IFA complications, and the industry introduced numerous technical improvements to assure patient safety.

自单极turp (mTURP)问世以来，所谓的经尿道电切综合征(tur -syndrome，简称turs)一直是一种令人恐惧的并发症。通常发生于灌洗液吸收（IFA）达到1000 mL时，而IFA＞2500ml则会导致急性症状。多年来，外科医生对IFA并发症的认识越来越深，且业界引入多种技术以确保患者安全。

Using saline as IF eliminates the risk of hemolysis, hyponatremia, and glycine intoxication and ensures the serum sodium levels postoperatively. Nevertheless, the pathophysiology of isotonic saline volume overload consists of a more pronounced plasma volume expansion due to the exclusive extracellular distribution and lack of osmotic diuresis. Acute cardiac decompensation and pulmonary edema can occur, which is of particular concern in the elderly, considering the possibility of very rapid fluid absorption (250 ml/min) .

使用生理盐水作为IF可降低溶血、低钠血症和甘氨酸中毒的风险，术后血清钠水平得到保障。然而，等渗生理盐水容量超负荷可能导致血容量明显增加，若灌洗液迅速吸收（250ml/min），老年人可能出现急性心衰和肺水肿，这一现象值得关注。

Morcellation of enucleated tissue is an integral part of transurethral enucleation of the prostate (EEP) and requires adequate bladder distension with increased filling volume and consequent high-intravesical pressures (IVP). There have been reports of large amounts of IF entering the circulation system or abdominal cavity during such procedures, potentially harming the patient. However, only a few endourologists remain cognizant and are aware of clinically significant and critical IFA.

Morcellation of enucleated tissue是经尿道前列腺剜除术(EEP)的重要组成部分，需要充分扩张膀胱，增加充盈量，从而增加膀胱内压（IVP）。此过程中大量的IF进入循环系统或腹腔会对患者造成伤害。但只有少数泌尿外科医生能够识别并警惕严重IFA。

Moreover, the impact of increased IFA in perioperative complications and the ways to prevent them by controlling IFA remains obscure.Due to the little knowledge of IFA when using saline as IF, we aimed to give an overview of incidence and amount of IFA for bTUR and laser procedures and discuss strategies to prevent excessive IFA.

IFA增加对围手术期并发症的影响以及如何通过控制IFA来预防并发症仍不清楚。以生理盐水作为IF时我们对IFA了解甚少，因此本文旨在概述bTUR和激光手术中IFA的发生率和数量，并讨论预防严重IFA的策略。

We performed a literature search from the 1st to the 30th of September 2020 using the PubMed database to identify original English publications. We included articles discussing IFA and TUR-syndrome. We judged all experimental and observational studies as eligible, including but not restricted to controlled clinical trials, case series, case–control, and cohort studies. We excluded reviews, comments, and editorials. Two experienced reviewers (GO, TT) conducted the literature search using the keywords TUR, transurethral, laser, HoLEP, ThuLEP, greenlight, enucleation, fluid absorption, fluid uptake, and TUR-syndrome. Boolean operators (AND, OR) were employed to augment the search process.

2020年9月1日至30日，我们使用PubMed数据库进行了文献检索，我们收录了讨论IFA和TURS的文献，允许纳入所有的实验性和观察性研究，包括但不限于对照临床试验、病例报道、病例对照和队列研究，排除综述、评论和社论。两位经验丰富的审稿人（GO，TT）使用的关键词包括TUR、transurethral、laser、HoLEP、ThuLEP、greenlight、enucleation、fluid absorption、fluid uptake和TUR综合征，使用布尔运算符（AND，OR）来扩充搜索过程.

The search identified 886 records. The authors initially reviewed all records by title or abstract. A list of articles judged to be highly relevant was distributed to the co-authors to reach a fnal consensus on the review structure. Hand-searching individual urological journals, citations, and reference lists were also evaluated, adding 42 records. A total of 928 unique references were screened for eligibility.

作者搜索到886条记录，首先按标题或摘要审阅所有文献，列出与本研究高度相关的文章分发给共同作者，最终就综述构成达成共识。此外，还对手工检索的泌尿外科期刊、引文和参考文献列表进行了评估，增加了 42 条记录，最终总共928篇参考文献被纳入评估。

Only studies providing quantitative data for IFA during bipolar or laser transurethral prostate surgery were considered relevant for the review. A total of 15 studies were merged in a qualitative synthesis (Fig. 1). Due to the already excessively studied classical TUR-syndrome, studies using monopolar energy were excluded due to the usage of electrolyte-free irrigation solution but are presented in a supplementary table.

只有在双极或激光经尿道前列腺手术中给出IFA 定量数据的研究才被认为与本研究相关，共有 15 项研究被合并为定性整合（图 1）。由于对于经典 TUR 综合征的研究已很充分，使用单极能量的研究使用无电解质冲洗溶液被排除在外，但会列于补充表中。

Because
of study heterogeneity and the non-standardized quality appraisal, a
narrative synthesis was performed. The limitations of using a single
database are taken into account . Moreover, outcomes may be limited by
selection bias. IFA was measured in mL, and either mean±SD or mean with
(range) was applied. Values were marked with additional labels (e.g.,
median) if no mean values or range was present.

由于研究的异质性和非标准化的质量评价，本研究采用了描述性整合的方法。但由于本研究使用单一数据库，且结果可能受选择偏移影响，因此存在一定局限性。IFA采用mL为单位，以平均值±SD或平均值(范围)标记。如果没有平均值或范围，值会用额外的标签(例如，中位数)标记。

Overview ofincluded bTURP and laser procedures

概述包括bTURP和激光手术

A total of 15 studies could be identified. We found six studies for bTURP (Table 1), and nine  for laser procedures (Table 2). Three studies compared mTURP to bTURP or bipolar vaporization of the prostate (bVP), one compared mTURP to Holmium laser enucleation of the prostate (HoLEP), and one compared bTURP to laser photoselective vaporization of the prostate (PVP).

最终确认了15项研究，其中6项关于bTURP的研究(表1)，9项关于激光手术的研究(表2)。3项研究比较了mTURP与bTURP或双极前列腺汽化术(bVP)， 1项研究比较了mTURP与钬激光前列腺汽化术(HoLEP)， 1项研究比较了bTURP与激光光选择性前列腺汽化术(PVP)。

bTURP (Table 1)

We could identify 6 studies with 506 patients. Continuous flow resectoscopes were utilized in four studies , intermittent flow with additional suprapubic trocar in one study, while two studies did not define the type of irrigation used . Irrigation fluid absorption was estimated with the breath ethanol test in all but one work . All types of anesthesia were applied. Surgeons set the irrigation pressure (IP) to 50–70 cm H2O .

bTURP（表1）

共纳入包含506例患者的6项研究，4项研究使用了连续切口切除术，1项研究使用了附加耻骨上套管针的间歇切口切除术，2项研究没有定义使用的冲洗类型。5项研究采用呼气乙醇测定法测定灌洗液的吸收量，各种麻醉方式均被应用，冲洗压力(IP)设置为50-70cm H2O。

During bTURP, mean IFA ranged from 133 to 915ml, and maximum IFA ranged from 1146 ml to more than 2000ml.In all three works comparing mTURP to bTURP, IFA was significantly lower for bTURP, and changes in serum sodium levels were significantly different between monopolar and bipolar resection. No significant differences could be demonstrated by directly comparing the IFA during mTURP (305±343 ml) and bVP (334±423 ml). No significant differences could be demonstrated by directly comparing IFA during bTURP (915±168 ml) and BipoLEP (863±173 ml). Despite the absence of a uniform TUR-syndrome definition throughout the bTURP studies, one patient (2%) experienced symptomatic fluid overload.‍

bTURP手术中，平均IFA范围133-915 ml，最大IFA范围为1146 - 2000 ml。mTURP与bTURP相比，后者IFA明显较低，单极和双极切除之间血清钠水平的变化也有显著差异。mTURP的IFA（305±343 ml)和bVP(334±423 ml)的IFA无显著差异。bTURP(915±168ml)和BipoLEP(863±173 ml)手术的IFA无明显差异。尽管在整个bTURP研究中没有统一的TURS定义，但仍有1例患者(2%)出现液体量超负荷相关症状。‍

We could identify 9 studies with 356 patients, none of them being randomized controlled studies. Different laser PVP procedures were performed in seven whereas HoLEP was performed in two studies. All but two study groups utilized continuous irrigation resectoscopes. Laser power ranged from 50 to 180W for laser PVP and from 80 to 100 W for HoLEP. Mean applied laser energy ranged from 155 kJ to 267 kJ and maximum energy reached 488 kJ. Surgeons applied an IP of 50–80 cmH2O, while a breath ethanol test was utilized in all studies for IFA assessment.‍

共纳入包含356例患者的9项研究，其中无随机对照研究。7项研究进行了分散激光PVP手术，而2项研究为HoLEP。7项研究组使用连续冲洗切除术。激光PVP功率范围为50-180 W，HoLEP功率范围为80 -100 W，激光平均能量为155 ~ 267 kJ，最大能量为488 kJ。外科医生应用50-80 cmH2O的IP，而在所有研究中使用呼吸乙醇测试来评估IFA。‍

Mean IFA was not present for all studies; therefore, the results are not comparable. Large IFA volumes (>1000–2000ml) were more common during laser PVP. TUR-syndrome incidence was observed in up to 9% of the cases.

并不是每项研究均列出平均IFA，因此结果不可比较。一般来说，最大IFA介于0 ml到4579 ml之间。大量IFA(大于1000-2000毫升)更常见于激光PVP中，TURS发生率高达9%。‍

mTURP

We identified 54 studies. Although most studies did not present TUR-syndrome rates, available data show an incidence of 33%. Of note, we could not identify a uniform definition for TUR-syndrome throughout the studies, but we observed a tendency for lower mean and maximum IFA values when surgeons applied continuous irrigation and lower IP.‍

共纳入54项研究，尽管大多数研究没有报道出TURS发生率，但现有数据显示其发生率为33%。尽管无法对TURS给出统一的定义，但我们观察到，当外科医生应用持续、低IP冲洗时，IFA的平均值和最大值有降低的趋势。‍

This review demonstrates that increments in IFA during bTURP and transurethral laser procedures are common, and significant symptomatic IFA (non-classical TUR-syndrome) with a risk of intensive care treatment occurs in up to 9% of cases. Maximum IFA of>2000 ml and>4500 ml is possible during bTUR and laser PVP, respectively.

这篇综述表明，在bTURP和经尿道激光手术中，IFA的增加比较常见，有明显症状的IFA(非经典的tur综合征)发生率高达9%，有重症监护治疗的风险。在bTUR和激光PVP中，最大IFA分别为2000毫升和4500毫升。‍

Mean and maximum IFA is significantly lower for bTURP than mTURP.  This assertion was most impressively demonstrated in a randomized controlled trial by Chen et al., in which mean IFA was 208 ml (range 0–1450 ml) for bTURP and 512 ml (range 0–3250 ml) for mTURP (p<0.001) . Our collated mTURP IFA data (supplementary table) suggest a higher mean and maximum IFA when compared to bTURP (Table 2).Nonetheless, this must be interpreted with caution due to the outdated mTURP studies and the use of old-technology equipment.‍

bTURP的平均和最大IFA明显低于mTURP。Chen等人在一项随机对照试验中地证实了这一说法，其中bTURP的IFA平均值为208 ml(范围0-1450 ml)， mTURP的IFA平均值为512 ml(范围0-3250 ml) (p<0.001)。我们整理的mTURP IFA数据(补充表)表明，与bTURP相比，mTURP的IFA平均值和最大值更高(表2)。由于mTURP相关研究技术老旧、已经过时，这一结论需谨慎看待。‍

The largest randomized trial comparing mTURP to bVP did not report a statistical IFA difference (334±423 vs. 305±343). Interestingly, this was the only study using a volumetric calculation of IFA with the aid of on-table weighing (IFA=weight gain+blood loss—intravenous fluids administered). Therefore, the results must be interpreted with care and might not be comparable to studies using other IFA measurement methods.‍

最大的对比mTURP和bVP的随机试验没有得到具有统计学意义的IFA差异(334±423 vs 305±343)。这是唯一一项借助表重计算IFA容量的研究(IFA=体重增加+失血量-静脉输液)。因此这一结果也需谨慎看待，并且可能无法与使用其他IFA测量方法的研究进行比较。‍

Regarding bVP, IFA>2000ml is more closely linked to TUR-syndrome and venous pH change is a useful indicator of significant absorption (7.41 vs. 7.34, p=0.002). Researchers found that IFA detection was more frequent with bTURP than with laser PVP (71% vs 39%; p=0.006). In the same study, IFA ranging from 500 to 1000 ml and maximum IFA>2000 ml was also more frequent in bTURP . Finally, researchers could not demonstrate significant differences in IFA by comparing bTURP (915±168 ml) to BipoLEP (863±173 ml) .‍

关于bVP, IFA>2000 ml与tur综合征相关性更高，静脉pH值变化则与显著吸收相关性更高(7.41 vs. 7.34, p=0.002)。研究人员发现，与激光PVP相比，bTURP更频繁地检测IFA (71% vs 39%;p = 0.006)。在同一研究中，500 - 1000 ml的IFA和最大的IFA>2000 ml在bTURP中也更常见。最后，研究人员无法确认bTURP(915±168 ml)和BipoLEP(863±173 ml)IFA是否存在显著差异。‍

Regarding laser procedures, Shah etal. were the first group publishing IFAs with a mean value of 459 ml (range 213–930 ml) in over 25% of patients during HoLEP , contrariwise Bapat et al. demonstrated IFAs not exceeding 300 ml. For laser PVP, Hermanns et al. reported significant IFA during second-generation 120 W Greenlight® PVP. In 22/50 (44%) of patients, IFA was detectable with a median value of 725 ml (range 138–3452 ml). Ten patients (20%) absorbed more than 1000 ml, 6 (12%) more than 2000 ml, and 1 (2%) more than 3000 ml. Three patients in the absorber group (14%) experienced TUR-syndrome symptoms.‍

关于激光手术，Shah等人首次发现在HoLEP期间，超过25%的患者的IFA平均值为459 mL（213-930 mL）。相反，Bapat等研究则表明IFA不超过300毫升。对于激光PVP，Hermanns等人在第二代120 W GreenLight®PVP期间报告了显著的IFA.在22/50（44%）的患者中检测到IFA，中位数为725 mL（138–3452 mL）。10例（20%）患者吸收超过1000ml，6例（12%）患者吸收超过2000毫升，1例（2%）超过3000毫升。吸收组中有3例患者（14%）出现了TURS症状。

The median operative time was 70min, and the median applied laser energy was 230 kJ (range 65–400 kJ),which was considerably higher than the data for the first generation Greenlight® system (mean 155 kJ, range 46–288 kJ) .Absorption usually occurred in the second half of the procedure. Smaller prostates received slightly more applied energy and experienced a higher bleeding intensity and more intraoperative events (capsular perforation, opened venous sinuses, or deep bladder neck incision).‍

中位手术时间为70分钟，应用激光能量的中值为230 kJ(范围65-400 kJ)，大大高于第一代Greenlight®系统的数据(平均155 kJ，范围46-288 kJ)。吸收通常发生在手术的后半段。前列腺体积越小、激光能量越高，出血强度越高，术中事件则越多(包膜穿孔、静脉窦打开或膀胱颈深切口)。

Porsch etal. compared Greenlight® PVP to bTURP and found that IFA occurred more often in the bTURP group (71% vs. 39%, p=0,006). Nevertheless, Mean IFA showed no significant difference (Greenlight® PVP: 337±242 ml vs. bTURP: 543±400 ml). Of note, prostate volume was significantly larger in the bTURP group (57 ± 20 ml vs. 47 ± 15 ml, p=0.016). There was no correlation between IFA and the amount of laser energy administered in the Greenlight® PVP group (p = 0.966). Interestingly, IFA occurred in only 43% of patients anesthetized epidurally, but in 70% of patients undergoing general anesthesia (p=0.029).‍

Porsch等人比较了Greenlight®PVP和bTURP，发现IFA在bTURP组中发生的频率更高(71% vs. 39%， p= 0.006)。但平均IFA显示无显著差异(Greenlight®PVP: 337±242 ml vs. bTURP: 543±400 ml)。bTURP组前列腺体积显著增大(57±20 ml vs. 47±15 ml, p=0.016)。在Greenlight®PVP组中，IFA与激光能量剂量之间没有相关性(p = 0.966)。只有43%的硬膜外麻醉患者发生IFA，但70%的全麻患者发生IFA (p=0.029)。‍

Furthermore, Wettstein et al. demonstrated a similar incidence of 41% for IFA with a risk of hyperchloremic acidosis during Greenlight® PVP. Median IFA was 950 ml (range 208–4579 ml), and high IFA (>2000 ml) occurred in almost 20% of the patients using vaporization energies up to 180 W. Intraoperative events such as capsular perforations and injury to prostatic sinuses plaid a major role and absorption occurred mainly in the second half of the procedure (median onset 65% of the operative time). Absorbers had smaller prostates and significant drops in hemoglobin (p=0.015), hematocrit (p=0.017), venous pH (p=0.001), bicarbonate (p=0.008) and increase in chloride (p=0.006). Maximum IFA velocities of up to 120 ml/min were observed with an average IFA velocity of 46 ml/min.‍

此外，Wettstein等人证实，在绿光PVP期间，IFA与高氯血症酸中毒风险的发生率相似，为41%。IFA中位950毫升(范围208-4579毫升)，高IFA (>2000毫升)出现在汽化能量高达180 W的患者中几乎20%。主要原因为术中囊穿孔和前列腺窦损伤，吸收主要发生在过程的后半段(中位发病时间为手术时间的65%)。高IFA人群前列腺更小，血红蛋白(p=0.015)、红细胞压积(p=0.017)、静脉pH (p=0.001)显著下降，碳酸氢盐(p=0.008)和氯(p=0.006)则更高。平均IFA速度为46 ml/min，最大IFA速度可达120ml/min。‍

Early-onset of IFA was associated with a high final absorbed volume. In the absorbers group, higher total energy per volume of prostatic tissue vaporized was recorded (5.98 kJ/ml; range 0.97–10.5 kJ/ml vs. 3.73 kJ/ml; range 0.94–5.86 kJ/ml). Five patients (9%) developed symptoms potentially related to iso-osmolar fluid overload. The authors concluded that macro coagulation with the 180 W XPS laser was challenging and could be responsible for the high IFA . Finally ,The only available study on Thulium laser vaporization of the prostate reported an incidence of IFA of 13% with a median IFA of 265 ml (227–615 ml) .‍

IFA的早期发作与较高的最终吸收量有关。在吸收剂组，单位体积前列腺组织汽化的总能量更高(5.98 kJ/ml;0.97-10.5 kJ/ml vs. 3.73 kJ/ml;范围0.94 - -5.86 kJ /毫升)。5例(9%)患者出现了可能与渗透压过载相关的症状。作者认为180w XPS激光的宏观凝固具有挑战性，可能是造成高IFA的原因。唯一一项关于铥激光手术的研究显示IFA发生率为13%，中位IFA为265毫升(227-615毫升)。‍

Pathophysiology of IFA and preventive measures (Table 3)‍

IFA的病理生理学及预防措施（表3）‍

The symptomatology of iso-osmolar fluid overload depends on the fluid amount per time entering the circulatory system. Rapid infusion of crystalloid solution (1250 ml/15 min) can lead to hand swelling, abdominal lump, dyspnea or headache . Metabolic acidosis and impairment of kidney function are known signs of iso-osmolar volume overload. With increased absorption, cardiac insufficiency, lung edema, and cardiac arrest can be observed .‍

等渗液体符合过重的症状取决于每次进入循环系统的液体量。快速输注晶体溶液(1250ml / 15min)可导致手部肿胀、腹部肿块、呼吸困难或头痛及代谢性酸中毒和肾功能损害等体征。随着吸收的增加，甚至可以出现心功能不全、肺水肿和心脏骤停。

There are two principal routes for irrigation fluid to enter the circulatory system: by direct intravascular (IVA) and indirect extravascular absorption (EVA) from a ‘leaking space’ (perivesical space, abdominal cavity) . By adding alcohol to the irrigation solution, Hahn et al. first described intraoperative IFA monitoring through exhaled air via a breath alcolmeter , a method that is nowadays widely accepted. Detecting significant IFA early during surgery allows a quick response of the surgical team . This becomes important if dangerous rapid fluid absorption velocities (>250 ml/min) are observed which can potentially lead to cardiac stress. Considering that a maximum IFA>4500 ml was reported during laser PVP , with an absorption velocity of 250 ml/min, the total volume would be absorbed in 18 min.‍

灌洗液进入循环系统的主要通过两种途径有：直接血管内吸收(IVA)和间接血管外吸收(EVA)。Hahn等人首次提出可以在洗液中加入酒精，通过计算呼出的酒精量来检测IFA，该方法目前已被广泛接受。激光PVP术中，若达到250ml/min的吸收速度，超过4500ml的IFA可在18min内及完成，可能导致心脏负荷过重，因此在手术早期发现IFA 非常重要，可以使手术团队快速反应。‍

Some well-known factors are involved in the pathophysiology of IFA: prostate size, the surgical method, instrument diameter, open venous structures, capsular perforation, resection depth, surgery duration, and IVP. Our group reported in a recent review that IVP is a major triggering factor in IFA, and is directly related to IP, which should be kept below 60 cmH2O.‍

一些众所周知的因素与IFA的病理生理学有关：前列腺大小、手术方法、器械直径、开放静脉结构、包膜穿孔、切除深度、手术持续时间和IVP。我们小组在最近的一篇综述中报道，IVP是IFA的主要触发因素，并且与IP直接相关，IP应保持在60cm H2O。‍

The relation of IVP and IFA is very complex and determined by a dynamic environment. Absorption occurs with IVPs ranging from 10.2 to 25.5 cmH2O (mean: 15.3 cmH2O) and significant IFA (>250 ml/10 min) occurs at considerably higher mean IVPs. Bladder compliance also influences IVP and IFA. High IVPs are reached rapidly in patients with small but are uncommon in patients with huge bladders . IFA seems to occur in the second half of bladder filling, starting with an average filling of about 500 ml.‍

IVP和IFA之间的关系非常复杂，是由动态环境决定的。膀胱顺应性也影响IVP和IFA。小膀胱患者可迅速达到高IVP，但巨大膀胱患者并不常见。IFA似乎发生在膀胱充盈的后半部分，开始时平均充盈约500毫升。‍

Interestingly, the type of anesthesia also has an impact on IVP: general and spinal anesthesia decrease intraabdominal pressure before and during TUR, but only spinal anesthesia significantly increases bladder compliance . Furthermore, it has also been shown that IVP is dependent on the type of irrigation system. Continuous flow (CF) resection is recommended to maintain low IVPs, reduce bladder overfilling, and distressing postoperative bladder atony risk. Therefore, CF resection is highly recommended for inexperienced surgeons .‍

麻醉类型对IVP也有影响：全身麻醉和腰麻可降低TUR术前和术中的腹内压，但只有腰麻可显著增加膀胱顺应性。此外，还表明IVP取决于灌注系统的类型。推荐连续血流（CF）切除以维持低IVP，减少膀胱过度充盈和术后膀胱无力风险。因此，对于经验不足的外科医生，CF切除术是值得推荐的。‍

Adding an active suction pump to the CF system leads to even lower IVPs [44]. A minimum flow of 300 ml/min seems to be necessary for good visibility but can be adapted according to the extent of bleeding and the surgeon’s skill. Flow rates above 1000 ml/min are unnecessary as they shorten effective operating time and can lead to higher blood loss during resection. Rising IVPs diminish the inflow and thus the visibility during TURP—this correlation is not linear.  Declining inflow is usually seen at a bladder filling of about 2/3 of the full bladder capacity. Prostatic capsule perforation leads to both IVA and EVA and is a significant risk factor for IFA. Absorption usually does not occur at the beginning of the procedure, but the risk increases with the resection depth and the number of opened veins . Finally, another essential factor for IFA is the procedure time, which should be held below 90 min . In general, CF achieves shorter procedure times .

CF系统引入主动抽吸泵可以带来更低的IVP。至少300毫升/分钟的速度对于保持良好的能见度是必要的，该数值可以根据出血的程度和外科医生的技术进行调整。而超过1000ml /min的速度尽管可以缩短手术时间，但可能会增加术中出血量，IVPs的增加可能会降低术中可见度，但这种相关性不是线性的。 前列腺包膜穿孔导致IVA和EVA，是IFA的重要危险因素，随着切除深度和开放静脉数量的增加，IFA风险也会增加。最后，IFA的另一个重要因素是手术时间，手术时间应控制在90分钟以下。一般来说，CF可以缩短手术时间。‍

Our findings highlight the clinical significance of IFA with saline as an irrigation solution. Preventing IFA during TURP is critical to assure patient safety, as iso-osmolar volume overload does not lead to a typical TUR-syndrome. There is evidence of iso-osmolar fluid overload requiring intensified care after bTURP and laser surgery. Breath ethanol monitoring should be considered intraoperatively and preventing high IFA must be an interdisciplinary aim, especially for patients with pre-existing co-morbidities. Based on the available data, bTURP achieves decreased IFA compared to mTURP and bVP but comparable IFA to EEP. Nevertheless, quantitative data supporting this conclusion is limited. Capsular perforations, open venous sinuses, deep bladder neck incision, prostate volume, operative duration, IVP, cumulative laser energy, and surgeon experience are linked to clinically significant IFA. Venous pH, serum chloride, and bicarbonate are potential markers for clinically significant IFA detection. Further research is deemed necessary to obtain more profound knowledge about IFA, especially with novel therapies.‍

我们的研究结果强调了生理盐水作为冲洗液对IFA的临床意义。在TURP期间预防IFA是确保患者安全的关键，因为等渗容量超负荷不会导致典型的TURS。有证据表明bTURP和激光手术后等渗液体超负荷需要加强护理。术中应考虑呼吸乙醇监测，预防高IFA需跨学科合作，特别是对于已有合并症的患者。根据现有数据，与mTURP和BVP相比，bTURP降低了IFA，与EEP相当。但支持这一结论的定量数据有限。包膜穿孔、开放的静脉窦、膀胱颈深部切口、前列腺体积、手术持续时间、IVP、累积激光能量和外科医生经验与具有临床意义的IFA相关。静脉pH值、血清氯化物和碳酸氢盐是具有临床意义的IFA检测的潜在标志物。有必要开展进一步的研究，以加深我们对IFA的更深刻的认识，探索新的治疗方法。‍