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01.12.2014 | Research article | Ausgabe 1/2014 Open Access

BMC Anesthesiology 1/2014

Transurethral resection syndrome in elderly patients: a retrospective observational study

Zeitschrift:
BMC Anesthesiology > Ausgabe 1/2014
Autoren:
Junko Nakahira, Toshiyuki Sawai, Atsushi Fujiwara, Toshiaki Minami
Wichtige Hinweise

Electronic supplementary material

The online version of this article (doi:10.​1186/​1471-2253-14-30) contains supplementary material, which is available to authorized users.

Competing interests

The authors declare that they have no competing interests.

Authors’ contributions

JN made substantial contributions to the conception, design and acquisition of data, and drafted the manuscript and tables. TS performed the statistical analysis and revised the manuscript critically for important intellectual content. AF participated in the design of the study and coordination and helped to draft the manuscript. TM made substantial contributions to the conception of the study and helped to draft the manuscript. All authors read and approved the final manuscript.

Background

Benign prostatic hyperplasia is common in elderly males. Transurethral resection of the prostate (TURP) is a standard surgical procedure for the management of benign prostatic obstructions. Non-conductive irrigation fluid is required during the use of monopolar electric resectoscope to clear the operating field. This hypotonic, electrolyte-free, nonconductive distension solution contains no electrolytes, and excessive absorption of it can cause fluid overload and dilutional hyponatremia. The associated adverse effects arising in both the cardiovascular and nervous systems are known as transurethral resection (TUR) syndrome. TUR syndrome has a multifactorial pathophysiology that is now better understood but still remains a risk.
Several studies over the last 20 years have shown mortality rates of 0.2–0.8% [ 1], and TURP is still associated with significant morbidity [ 2, 3]. The most frequent complication of conventional TURP is perioperative bleeding, which, in a significant number of cases, may necessitate blood transfusion. The most serious complication of conventional monopolar TURP is TUR syndrome, the frequency of which varies considerably in the literature, ranging from 0.18 to 10.9% [ 4, 5]. The symptoms of TUR syndrome are central nervous disturbances such as dizziness, headache, nausea, vomiting, and apnea, and circulatory abnormalities such as hypertension, hypotension, bradycardia, and arrhythmia. Anesthesiologists need to remain vigilant for such signs of TUR syndrome during surgery. Left undiagnosed, this syndrome can lead to lung or cerebral edema [ 6]. Therefore, spinal anesthesia is often recommended for TURP procedures so that early signs of neurological deterioration can be detected.
TUR syndrome can occur during other operations, including transcervical resection of the endometrium, TUR of bladder tumors, cystoscopy, arthroscopy, and vesical ultrasonic lithotripsy. However, TURP has an extremely high incidence of TUR syndrome. Theoretical risk factors are opened prostatic sinuses, high irrigation pressures, lengthy resection, and hypotonic irrigation solutions [ 7]. According to a past report, 77% of patients undergoing TURP had significant pre-existing medical conditions. Increased morbidity was found in patients with a resection time greater than 90 min, gland masses greater than 45 g, acute urinary retention, age greater than 80 years, and in those of African descent [ 8]. The aim of the present study was to identify risk factors related to TUR syndrome in the elderly.

Patients and methods

After obtaining approval from the Ethical Committee of Osaka Medical College, data on all elderly males (aged 70 years and older) who underwent TURP with regional anesthesia from April 2006 to March 2011 at our institution were retrospectively reviewed. Spinal anesthesia (L3/4 or L4/5) and epidural tubing (L1/2 or L2/3) were administered before the operations. 0.5% hyperbaric bupivacaine hydrochloride hydrate (1.8–3.2 ml) as a spinal anesthetic was used to obtain analgesia up to the T (Thoracic) 10 level. Cases of failed spinal anesthesia converted to general anesthesia were excluded from the analysis. If the T levels were lower or the operation time continued over 1.5 h, 0.375% ropivacaine hydrochloride (3.0–5.0 ml) was administered via the epidural tube. Postoperative analgesia was obtained using continuous epidural anesthesia of 2–5 ml/h of 0.2% ropivacaine. The surgical interventions were performed with monopolar electronic retroscope by surgeons with the same qualifications and clinical experience. D-sorbitol 3% was used as the nonconductive irrigation fluid. Bags were placed 90 cm above the operating table. Hemodynamic monitoring included heart rate, electrocardiogram, systolic and diastolic blood pressures every 2 min, and percutaneous oxygen saturation. Exclusion criteria included patients with bleeding disorders or existing coagulopathy and renal insufficiency, as well as any contraindication to spinal anesthesia. All patients were preloaded with an infusion of lactated Ringer’s fluid before induction of spinal anesthesia.
TUR syndrome was defined as the presence of central nervous system disturbances such as nausea, vomiting, restlessness, pain, confusion, or even coma with circulatory abnormalities both intra- and post-operatively. A checklist recommended by Hahn et al. to grade symptoms was used (Table  1) [ 9]. The presence of at least one circulatory disorder and one neurological disorder is necessary for a diagnosis of TUR syndrome. For circulatory abnormalities such as hypertension (>30% above baseline systolic blood pressure), hypotension (systolic blood pressure <80 mmHg), bradycardia, and arrhythmia, immediate treatment was prepared to avoid deterioration. For systolic blood pressures less than 80 mmHg, 4 mg of ephedrine hydrochloride was immediately administered intravenously. Medical and nursing personnel were intimately involved in patient care, in the monitoring and assessment of complications and the incidence and severity of TUR syndrome in the postoperative period.
Table 1
Severity score
 
Severity score
 
1
2
3
Circulatory
 Chest pain
Duration < 5 min
Duration > 5 min
Repeated attacks
 Bradycardia
HR decrease 10–20 bpm
HR decrease > 20 bpm
Repeated decreases
 Hypertension
SAP up 10–20 mmHg
SAP up > 30 mmHg
Score (2) for 15 min
 Hypotension
SAP down 30–50 mmHg
SAP down > 50 mmHg
Repeated drops > 50 mmHg
 Poor urine output
Diuretics needed
Repeated use
Diuretics ineffective
Neurological
 Blurred vision
Duration < 10 min
Duration > 10 min
Transient blindness
 Nausea
Duration < 5 min
Duration 5–120 min
Intense or > 120 min
 Vomiting
Single instance
Repeatedly, < 60 min
Repeatedly, > 60 min
 Uneasiness
Slight
Moderate
Intense
 Confusion
Duration < 5 min
Duration 5–60 min
Duration > 60 min
 Tiredness
Patient says so
Objectively exhausted
Exhausted for > 120 min
 Consciousness
Mildly depressed
Somnolent < 60 min
Needs ventilator
 Headache
Mild
Severe < 60 min
Severe > 60 min
A checklist used to define and score symptoms included in the TUR syndrome [ 9]. HR, heart rate; SAP, systolic arterial pressure.
Patients were divided into two groups, positive and negative, for the occurrence of the syndrome, and their risk factors were evaluated accordingly. Observational parameters were patient characteristics, dosage of local anesthesia, duration of the operation, weight of resected mass, volume of Ringer’s fluid, volume of plasma substitute, and whether continuous drainage of irrigation fluid through a suprapubic cystostomy via a pigtail drainage catheter (Angiomed Gmbh & Co. Medizintechnik Kg, Karlsruhe, Germany) was performed (Figure  1). Hespander (Fresenius Kabi Japan, Tokyo, Japan), which contains hydroxyethyl starch 6.0 g/100 ml, was used for the plasma substitute. Only variables with p < 0.05 on univariate analyses were included in the multivariate logistic regression model to determine their correlation with TUR syndrome. Whether or not the patients became symptomatic, adequate therapeutic measures were taken to prevent further complications. Timing of blood samples was at the discretion of the anesthesiologists or surgeons.

Statistical analysis

Univariate logistic regression analyses using parameters judged to be risk factors for TUR syndrome in the literature [ 1], including age, body weight, and operating time, etc., were performed. Only observational variables with p < 0.05 in univariate analyses were included in the multivariate logistic regression model to ascertain their independent effects on TUR syndrome. The odds ratio and p values were calculated for each variable. A p value of < 0.05 was considered significant. Analysis was performed using the statistical analysis software SPSS version 17.0 for Windows (SPSS, Chicago, IL, USA).

Results

A total of 98 patients with a median age of 76 (range, 70–91) years was included in this study. Of these, 23 had TUR syndrome (23.5%, 95% CI 14.9–32.0%). Initial circulatory abnormalities were mainly hypertension with reflex bradycardia, or sudden hypotension. In terms of patient characteristics and preoperative data, there were no significant differences between the two groups (Table  2). For grading symptoms, the checklist was used. The severity score of all of the patients with TUR syndrome was 2 and greater at the end of the procedure. Patients with a score of 3 were handled using additional anesthetic agents such as propofol or midazolam administered intravenously to support respiratory status and relieve pain immediately. In six of the 23 TUR syndrome patients, additional anesthesia including drugs for nausea was needed owing to the severity of their symptoms. One of the TUR syndrome patients was intubated owing to the severity of cardiovascular and neurological symptoms. One patient without TUR syndrome had an esophageal hemorrhage after the procedure because of esophageal variceal rupture. One patient without TUR syndrome during the procedure had postoperative nausea and vomiting. All transfusions were preoperative autologous blood donations except for one patient with TUR syndrome, who received allogeneic transfusion of red blood cells.
Table 2
Patients’ characteristics
 
TUR syndrome
 
Parameter
Yes (n = 23)
No (n = 75)
p value
Age, years
77.5 ± 5.2
75.4 ± 4.5
0.115
Height, cm
163.9 ± 6.5
162.8 ± 5.6
0.414
Body weight, kg
61.4 ± 9.3
60.6 ± 7.9
0.296
Diabetes mellitus
3 (13.0%)
12 (16.0%)
0.512
Hypertension
4 (17.4%)
11 (14.7%)
0.488
CRF
1 (4.3%)
2 (2.7%)
0.556
Cardiac disease
0 (0.0%)
2 (2.7%)
0.081
Preoperative serum data
     
  Creatinine
0.9 ± 0.4
0.9 ± 0.4
0.612
  BUN, g/dl
15.9 ± 6.8
16.7 ± 8.2
0.802
  Sodium, mol
140.6 ± 2.4
140.3 ± 2.8
0.446
  Hemoglobin, g/dl
13.5 ± 1.1
13.6 ± 1.7
0.837
  Hematocrit,%
39.1 ± 3.2
39.6 ± 4.9
0.819
Data expressed as means ± SD or number (%). TUR syndrome was defined as the presence of central nervous system disturbances such as nausea, vomiting, restlessness, pain, confusion, or even coma with circulatory abnormalities both intra- and post-operatively.
CRF, chronic renal failure; BUN, blood urea nitrogen.
Duration of operation ≥ 1.5 h, weight of resected mass > 45 g, volume of plasma substitute ≥ 500 ml, and continuous irrigation through a suprapubic cystostomy were significantly associated with TUR syndrome on univariate analyses (Table  3). Multivariate regression analysis showed that weight of resected mass > 45 g, volume of plasma substitute ≥ 500 ml, and continuous irrigation were associated with a significantly increased risk for TUR syndrome (Table  4).
Table 3
Operative and postoperative data
 
TUR syndrome
 
Parameter
Yes (n = 23)
No (n = 75)
p value
Continuous irrigation fluid drainage
14 (60.9%)
12 (16.0%)
< 0.001
0.5% Bupivacaine, ml
2.4 ± 0.4
2.4 ± 0.4
0.979
Resection weight, g
56.2 ± 31.0
30.8 ± 24.9
0.251
Resection weight > 45 g
14 (60.9%)
13 (17.3%)
< 0.001
Operation time, min
106 ± 39
70 ± 27
0.041
Operation time ≥ 1.5 hours
15 (65.2%)
19 (25.3%)
< 0.001
Plasma substitute, ml
367 ± 523
21 ± 99
< 0.001
Plasma substitute
11 (47.8%)
4 (5.4%)
< 0.001
Plasma substitute ≥ 500 ml
9 (39.1%)
3 (4.0%)
< 0.001
Saline, ml
200 ± 36
123 ± 149
0.005
Ringer fluid, ml
426 ± 329
431 ± 241
0.396
Symptom
23 (100.0%)
NA
NA
  Restlessness
14 (60.9%)
NA
NA
  Vomiting
11 (47.8%)
NA
NA
  Nausea
8 (34.8%)
NA
NA
  Pain
15 (65.2%)
NA
NA
Transfusion
16 (69.6%)
15 (20.3%)
< 0.001
Diuretics
4 (17.4%)
3 (4.0%)
0.051
Sodium chloride, mol
1.4 ± 3.3
0.2 ± 1.3
< 0.001
Postoperative serum data
     
  Creatinine, mg/dl
1.0 ± 0.6
1.0 ± 0.4
0.382
  BUN, mg/dl
13.5 ± 7.4
14.3 ± 9.0
0.839
  Sodium, mEq/l
132.7 ± 8.4
137.6 ± 3.8
< 0.001
  Hemoglobin, g/dl
10.7 ± 1.4
12.5 ± 1.8
0.081
  Hematocrit, %
31.4 ± 4.0
36.1 ± 5.4
< 0.001
Data expressed as mean ± SD or the number of patients (%). TUR syndrome was defined as the presence of central nervous system disturbances such as nausea, vomiting, restlessness, pain, confusion, or even coma with circulatory abnormalities both intra- and post-operatively. NA, not applicable; TUR, transurethral resection; BUN, blood urea nitrogen.
Table 4
Multivariate analysis
Parameter
Odds ratio
95% Confidence interval
p value
Plasma substitute ≥ 500 ml
14.7
2.9–74.5
0.001
Continuous irrigation fluid drainage
4.7
1.3–16.7
0.018
Resection weight > 45 g
4.7
1.2–14.7
0.029
Accuracy 84.7%, Hosmer-Lemeshow test, p = 0.944.

Discussion

In the present study, TUR syndrome was defined as the presence of one or more cardiovascular symptoms and one or more neurological symptoms. In previous reports, the occurrence of TUR syndrome varied, with a range of 0.5 to 10.5%, because few studies used a clear definition. Many previous studies defined TUR as sodium concentrations of 125 mmol/l or less after TURP with two of the following symptoms: nausea, vomiting bradycardia, hypotension, chest pain, mental confusion, anxiety, paresthesiae, and visual disturbance [ 10]. According to our clinical data and experience, not all patients with dynamic cardiovascular and neurological symptoms have serum sodium levels of 125 mmol/l or less. When a patient has only one symptom, the serum sodium level can be more than 135 mmol/l. In the present study, the rate of incidence of TUR syndrome was higher than in past reports. There are two possible reasons for this. One is the advanced age of the patients in the present study, because circulatory abnormalities are a greater risk in elderly patients. Another possible reason is that serum sodium levels were not included in the present definition of TUR syndrome. As mentioned, the serum sodium level is even more than 135 mmol/l at the beginning of TUR syndrome. If the patient’s status deteriorated, treatment was performed to avoid the occurrence of more severe symptoms. With respect to other conditions, D-sorbitol 3% was used as the nonconductive irrigation fluid. Bags were placed 90 cm above the operating table. Hahn et al. reported no significant differences in the volume of irrigation fluid absorbed at different bag heights [ 1]. The safe height for the irrigation fluid during TURP remains controversial, but it may affect the quantity of fluid absorbed.
As many previous studies showed, significant risk factors for TUR syndrome were duration of operation > 1.5 h and weight of resected mass > 45 g [ 8]. Despite all technical advances, resection speeds of between 0.5 and 0.9 g/min have not shown significant improvement [ 6]. In contrast, Akata et al. reported that changes in serum sodium during TURP correlated with rapid absorption in cases when the capsular veins and the prostate sinus are injured, but not with resection times [ 11]. Volume of plasma substitute ≥ 500 ml during the operation was found to be a significant risk factor for TUR syndrome in the present study. Plasma substitute contains colloids with a slightly higher osmotic pressure than Ringer’s solution or saline and it is administered from the beginning of the surgery against hypotension caused by spinal anesthesia [ 12]. Theoretically, excessive serum dilution should have been avoided.
More importantly, continuous drainage of irrigation fluid through a suprapubic cystostomy was found to be another risk factor in the present study. Continuous fluid drainage is useful for removing debris and blood in the operating field and in removing postoperative blood clots. This allows surgeons to continue the procedure without interruption. However, according to our observations, a number of patients had abdominal swelling owing to irrigation fluid leaking from the drainage point into the extraperitoneal space and abdominal cavity. Interestingly, Hahn et al. reported on evacuation of irrigation fluid from the bladder. Keeping the intravesical pressure below 2 kPa is the best strategy for reducing fluid absorption. The drainage catheter may not have been effective because it had a small diameter [ 13]. Extracellular electrolytes diffuse into the deposited irrigating fluid [ 14]. Abdominal pain, which may radiate to the shoulder, is a common first sign of extravasation [ 15]. Then, even if a suprapubic cystostomy should be inserted into the extraperitoneal area, the peritoneum can absorb large amounts of leaked irrigation fluid. This can induce hyponatremia in the patients. This fall in serum electrolytes is commonly followed by hypovolemia, with bradycardia and arterial hypotension. Hyponatremia is most pronounced 2–4 h later [ 15], but this extravasation may go undetected until the next day [ 16].
Generally, regional anesthesia should be performed during operations in which TUR syndrome might occur, because spinal anesthesia allows early detection of changes in mental status. However, the effectiveness of this approach is still controversial [ 17]. Symptoms of TUR syndrome may not be directly related to hyponatremia. Nevertheless, frequent blood sampling is required to accurately monitor serum sodium levels. Adding ethyl alcohol to the irrigation fluid may allow early detection of the absorption of irrigation fluid by permitting analysis of the alcohol content in the exsufflated air [ 18, 19].
Hypotension during TURP can be caused by three factors: adopting a combination of epidural and spinal anesthesia; hyponatremia; and vagovagal reflex caused by filling of the bladder. It is difficult to distinguish between these phenomena. We carefully used the epidural anesthesia to avoid a sudden reduction in blood pressure. Continuous epidural anesthesia was used mostly with 5 ml/h of 0.2% ropivacaine. Vagovagal reflex may be judged as a cardiovascular abnormality.
Recently, the advent of bipolar electrodes for coagulation has allowed the use of electrolytic irrigation fluid [ 10]. Although this can decrease the risk of TUR syndrome, researchers have reported longer operative times owing to smaller and finer resection loops and a higher rate of postoperative urethral stricture [ 20, 21]. Likewise, Holmium laser enucleation of the prostate (HoLEP) may become an alternative to standard TURP in the future. However, despite the reported decreases in bleeding, TUR syndrome remains a possibility with HoLEP [ 22].

Conclusions

In this study, weight of resected mass > 45 g, volume of plasma substitute ≥ 500 ml, and continuous irrigation were associated with a significantly increased risk for TUR syndrome. Our results suggest that the use of a plasma substitute and continuous irrigation through a suprapubic cystostomy must be avoided during TURP procedures in the elderly to reduce the risk of TUR syndrome.

Acknowledgments

We thank Teruo Inamoto from the Department of Urology in Osaka Medical College for his contribution to the concept and interpretation of this study.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://​creativecommons.​org/​licenses/​by/​2.​0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver ( http://​creativecommons.​org/​publicdomain/​zero/​1.​0/​) applies to the data made available in this article, unless otherwise stated.

Competing interests

The authors declare that they have no competing interests.

Authors’ contributions

JN made substantial contributions to the conception, design and acquisition of data, and drafted the manuscript and tables. TS performed the statistical analysis and revised the manuscript critically for important intellectual content. AF participated in the design of the study and coordination and helped to draft the manuscript. TM made substantial contributions to the conception of the study and helped to draft the manuscript. All authors read and approved the final manuscript.
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