“腰肋悬空”仰卧位经皮肾镜术在高危及肥胖患者中的应用

目的探讨采用一种新型体位—＂腰肋悬空＂仰卧位进行经皮肾镜碎石取石术在高危（心肺功能不全）及肥胖患者中应用的安全性及有效性。方法采用该新仰卧位进行经皮肾镜碎石术治疗肾结石20例。其中男性10例,女性10例,平均年龄（55.3±10.7）岁;结石长径2~6cm,平均（2.72±1.05）cm。其中美国麻醉师协会ASA麻醉分级Ⅲ级患者12例,肥胖患者8例;均采用椎管麻醉,在B超引导下穿刺肾盂成功后,依次扩张通道至16或20F,用钬激光或三代超声将结石完全击碎。结果所有患者均穿刺成功且均能良好耐受手术,无1例患者因体位不适提前终止手术。平均手术时间为（87.90±34.98）min。一次性结石清除率达到80%,残留结石4例,其中2例二期手术取尽结石。所有患者均未输血;无胸膜、腹腔脏器损伤等并发症发生。结论采用＂腰肋悬空卧位＂进行超声引导下经皮肾镜碎石取石术安全有效、耐受性好,临床上有很好的应用价值。     

患侧腰部抬高45°仰卧位经皮肾镜碎石术治疗肥胖及高危患者肾、输尿管上段结石（102例报告）

目的探讨肥胖及高危患者患侧腰部抬高45°仰卧位经皮肾镜碎石清石术（percutaneous nephrolithotomy,PCNL）的临床价值。方法总结2004年7月～2011年9月我院102例肥胖及高危肾输尿管上段结石患者患侧腰部抬高45°仰卧位PCNL的临床资料,肥胖25例,BMI 24～34;高危77例,合并中重度肺部疾患、高血压病、糖尿病及慢性肾功能不全等。肾结石77例,长径2.2～5.5 cm;输尿管上段结石25例,长径1.5～2.6 cm。PCNL时联合应用气压弹道以及超声碎石。结果 102例均顺利完成手术,无中转开放,无胸膜损伤及周围脏器损伤等并发症。术后4～10天复查X线、B超或CT,结石清除率89.2%（91/102）。11例肾盂或肾盏残余结石,最大径1.1～1.8 cm,行ESWL碎石。结论患侧腰部抬高45°仰卧位PCNL对肥胖及高危肾输尿管上段结石患者安全、可行。     

腰肋悬空仰卧位下经皮肾镜取石术的临床研究

目的 研究腰肋悬空仰卧位下PCNL治疗肾和输尿管上段结石的安全性及有效性.方法2010年3-10月采用腰肋悬空仰卧位PCNL治疗泌尿系结石患者173例.平均年龄(50±11)岁.结石位于左侧70例,右侧97例,双侧6例.肾结石166例,输尿管上段结石7例.结石最大径1.5～6.0 cm,平均(2.9±1.0)cm.该体位将患侧肩部及臀部分别用3 L水袋或气囊垫高,使患侧腰肋部悬空,同时建立腰桥.均采用椎管麻醉,B超引导下穿刺肾盂或目标肾盏成功后,依次扩张通道至16 F或20 F,用钬激光或EMS碎石清石系统碎石. 结果 173例均穿刺成功并能良好耐受手术,患者无因体位不适终止手术者.平均手术时间(86±34)min.一次性结石清除率为80.3%(139/173),残留结石34例,其中行二期手术取净结石16例.术后输血治疗1例;无胸膜、腹腔脏器损伤等并发症发生. 结论腰肋悬空仰卧位下PCNL安全有效,患者耐受性好.

Abstract：

Objective To investigate the safety and efficacy of percutaneous nephrolithotomy (PCNL) in a new operative position, flank suspended supine position. Methods The new position hold affected flank suspended by raising the ipsilateral shoulder and haunch with two 3-liter saline bags, and set up waist bridge simultaneously. From March 2010 to October 2010, a series of 173 patients underwent PCNL with the new supine position under epidural anesthesia. The average age was (50± 11) years, and the average bulk of the stone was (2. 9±1.0) cm. All patients were placed in the new supine position. Under ultrasound guidance, the desired calix or pelvis was punctured near the posterior axillary line, then dilating the tract and establishing the 16 F or 20 F tract for PCNL. Results The pelvicaliceal system could be successfully approached in all patients. The procedure was well tolerated in all patients. Mean operation time was (86 ± 34) min. 80. 3% of the patients were rendered free of stones by the initial PCNL. Thirty-four cases had residual stones, and a second PCNL was performed in 16 cases to clear the residual stones. Only 1 patient required blood transfusion.None of the patients suffered visceral injury. Conclusion The new supine position is safe and effective for PCNL.     

Lateral decubitus position for percutaneous nephrolithotripsy in the morbidly obese or kyphotic patient

BACKGROUND AND PURPOSE: Morbidly obese or debilitated patients do not tolerate the prone position used for percutaneous nephrolithotripsy (PCNL) well and may suffer from severe cardiorespiratory compromise in this position. The purpose of this study is to demonstrate a simple way to overcome this difficulty. PATIENTS AND METHODS: Two morbidly obese patients, ages 48 and 32 years, with Body Mass Indices of 47.5 and 43.2 and a 68-year old patient severely debilitated by multiple cerebral infarctions, ischemic heart disease, and kyphosis suffered from relatively high renal stone burdens. For PCNL, the patients were placed in the lateral decubitus position. To obtain an anteroposterior projection in this position, the C-arm fluoroscopy unit was tilted to one side and the operating table to the other. Tract dilation, stone fragmentation, and fragment extraction were performed with the patient in this position. RESULTS: An attempt to perform PCNL in the prone position in the first patient was aborted because of severe hypoxemia and hypercarbia. In the lateral decubitus position, the procedures were easily performed in all patients without any complications. It was noted that by rotating the C-arm to a perpendicular position, it was possible to perform nephroscopy and use fluoroscopy simultaneously. CONCLUSION: We highly recommend using the lateral position for PCNL in morbidly obese patients and in patients suffering from kyphosis. This position is safe and convenient.     

Flexible ureteroscopic lithotripsy: first-line therapy for proximal ureteral and renal calculi in the morbidly obese and superobese patient

BACKGROUND AND PURPOSE: The surgical treatment of kidney and proximal ureteral stones in morbidly obese patients (>14 kg/m2) remains difficult because shockwave lithotripsy is precluded by weight limitations and percutaneous nephrolithotomy is associated with difficult access and a high (9%) rate of transfusion. We review our experience with retrograde ureteroscopic lithotripsy in morbidly obese patients with renal and proximal ureteral stones. PATIENTS AND METHODS: Between December 1992 and April 2000, five women and three men with a mean age of 46.5 years (range 33-68 years) and a mean body mass index of 54 (range 45-65.2) underwent 10 independent ureteroscopic procedures for urolithiasis. The average stone size was 11.1 mm (range 5-25 mm). Lithotripsy was performed with the holmium laser in eight patients (60%) the electrohydraulic lithotripter in four (30%), and the tunable-dye laser in the remaining patient. Stone-free status was defined as no stones visible on a plain film with nephrotomograms or CT scan at 3 months. RESULTS: The mean operation time was 101 minutes (range 45-160 minutes), and 60% of the procedures were done on an outpatient basis. After the initial procedure, the stone-free rate was 70%. Two patients had fragments <4 mm, and no further therapy was undertaken. There was one complication: transient renal insufficiency (serum creatinine concentration 3.7 mg/dL) secondary to aminoglycoside toxicity. No transfusions were needed. CONCLUSION: In the morbidly obese patient with symptomatic stones <1.5 cm, ureteroscopic lithotripsy is safe, successful, and efficient.     

Tubeless percutaneous neprolithotomy: the new gold standard

PURPOSE: We present our experience with tubeless percutaneous nephrolithotomy (PCNL). PATIENTS AND METHODS: Between July 2004 and December 2006, 121 patients (82 males and 39 females) with 18-70 mm (mean 31.19 mm) renal stones underwent tubeless PCNL leaving only a 6 Fr externalized ureteric catheter. Their ages ranged between 4 and 80 years (mean 37.27). Two patients had bilateral disease, so a total of 123 renal units are included. The procedure was performed under general anesthesia in the prone (110 units) or supine position (13 units). A total of 133 punctures were performed. The punctures were single (114 units), double (8 units), or triple (1 unit). The approach was subcostal through the lower calyx (n = 110) or middle calyx (n = 10), or supracostal through the middle calyx (n = 8) or upper calyx (n = 5). RESULTS: Mean operative time was 46.30 min (range 15-100). Mean reduction in hemoglobin level was 1.57 g (range 0.3-4) with blood transfusion rate 4.13%. Complication rate was 9.9% in the form of perirenal collection (five patients), urinary leakage (two patients), fever (four patients), and hydrothorax (one patient). The ureteric catheter was left for 7-72 h (mean 45.67). Postoperative analgesia was required in 22 patients (18.2%) with mean 22.9 mg diclofenac sodium per patient. Mean hospital stay was 50.69 h (range 12-96) with 106 units (86.18%) rendered stone free, 13 (10.57%) with insignificant residuals, and four units (3.25%) were left with significant residual stones. CONCLUSIONS: Tubeless PCNL is a good option in non-complicated PCNL with the advantages of reduced hospital stay, low postoperative pain, and little need for postoperative analgesia.     

Percutaneous stone surgery in the obese: outcome stratified according to body mass index

OBJECTIVE: To report our experience of percutaneous surgery for treating renal pelvicalyceal stones over 6 years, to show that this approach is feasible and safe in obese and morbidly obese patients, as the prevalence of obesity and stone disease has risen in the last 20 years. PATIENTS AND METHODS: We retrospectively reviewed the results of 223 percutaneous nephrolithotomies (PCNLs) by one urologist between 1995 and 2001. Patients were stratified into four groups according to the World Health Organization classification of body mass index (BMI), i.e. <25, 25-29.9 (overweight), 30-39.9 (obese) and > 40 kg/m(2) (morbidly obese). The outcomes of surgery in these four groups were compared. RESULTS: There were no statistically significant differences in operative duration, decrease in haemoglobin concentration, postoperative analgesic use, hospital stay and stone-free rates; nor was there a higher complication rate in patients who were obese. CONCLUSION: The outcome of PCNL is independent of the patients' BMI and results can be favourable in most patients. We therefore advocate treating obese patients with symptomatic stone disease based on individual status, using percutaneous surgery where appropriate.     

Percutaneous nephrolithotomy in children: early and late anatomical and functional results

PURPOSE: We report our experience with percutaneous nephrolithotomy (PCNL) in children, and evaluate its early and late anatomical and functional results. MATERIALS AND METHODS: A total of 65 children with renal calculi were treated with PCNL. Patient age at operation ranged from 9 months to 16 years (mean +/- SD of 5.9 +/- 0.9 years), and 27 (41.5%) were younger than 5 years. Seven patients had bilateral renal stones and, therefore, the number of kidneys treated by PCNL was 72. The patients were followed regularly every 3 months during year 1 and every 6 months thereafter. Renal scans using technetium dimercapto-succinic acid for detection of renal scarring and technetium diethylenetetramine-pentaacetic acid for determination of selective glomerular filtration rate (GFR) were performed in all patients at least once during followup, which ranged from 6 to 72 months (mean +/- SD 40 +/- 10). RESULTS: Early complications included significant intraoperative bleeding in 1 case, renal pelvis perforation in 1 and transient fever in 2. Mean hospital stay +/- SD was 3 +/- 1.2 days (range 2 to 21). Of the renal units 62 (86%) were stone-free after a single PCNL, and the remaining 10 with residual stones were treated with a second look PCNL (4) and shock wave lithotripsy (6). Stone-free rates at hospital discharge and at 3 months were 93% and 100%, respectively. During followup 6 patients (9%) had recurrence of small renal stones and were successfully treated with shock wave lithotripsy. None of the kidneys had scarring on dimercapto-succinic acid renal scan. All of the kidneys except 1 showed improvement or stabilization of the corresponding GFR determined by diethylenetetraminepentaacetic acid renal scan. Comparison of the mean preoperative GFR of the corresponding kidney (28.8 +/- 11.2 ml per minute) with mean value at followup (36.1 +/- 9.9) showed an increase of statistical significance (p <0.01). CONCLUSIONS: PCNL is a safe and effective procedure for the treatment of children with renal calculi. At long-term followup the procedure improves renal function without renal scarring.     

GPS导航超声系统实时定位穿刺PCNL处理复杂肾结石22例报告

目的：探讨GPS导航超声系统（SonixGPS）引导定位穿刺在经皮肾取石术（PCNL）中的优势及安全性。方法：2012年5月～2012年9月，我们应用SonixGPS行经皮肾穿刺，建立Ft。皮肾通道进行取石处理复杂肾结石22例，其中男17例，女5例，年龄46～70岁，平均51．2岁。重复。肾畸形合并结石1例，肾多发结石16例，铸型肾结石2例，输尿管上段结石并肾结石3例。全部患者采用全身麻醉，用预先消毒好的超声探头在11肋间或12肋缘下区域扫查，了解结石的分布、位置、大小及和集合系统的关系情况，确定穿刺径路，皮肾通道建立成功后全部应用钬激光进行碎石。结果：借助SonixGPS穿刺，22例患者全部一次成功。除1例多发结石因残余结石行二期PCNL外，其余21例患者均一期取石成功，无一例出现术中或术后严重并发症。结论：SonixGPS可以实时追踪并显示穿刺针的方向和深度，特别对于经皮肾穿刺取石手术初学者，可以帮助清楚显示穿刺针位置，提高穿刺成功率，缩短学习曲线，可为PCNI。超声定位穿刺提供一种新的选择。     

高危及肥胖患者经皮肾镜碎石术采用腰肋悬空仰卧位效果观察

目的 提高高危及肥胖肾结石患者经皮肾镜碎石术(PCNL)的安全性.方法 将40例行PCNL的高危及肥胖患者随机分成观察组和对照组各20例.对照组取传统的俯卧位;观察组取腰肋悬空仰卧位,即于患侧肩部、臀部分别用3L水袋或气囊垫高14～18 cm,使患侧腰肋部悬空.结果 观察组PCNL耐受性显著好于对照组(P＜0.01);...     

Percutaneous nephrolithotomy in semisupine position: a modified approach for renal calculus

Conventional percutaneous nephrolithotomy (PCNL) is usually performed in a prone position, which compresses the thorax and results in difficulty in rescue during operation. When PCNL is performed in a supine position, the flank renal puncture area is limited, so it is difficult to treat disseminated and complex renal calculi. Herein, we introduce a modified semisupine position for performing PCNL, which has numerous benefits as well as safe and effective. Between May 2002 and May 2009, a total of 452 patients with renal calculi were treated with semisupine PCNL. The patient was placed in 45° semisupine position during the procedure, with the affected flank arched as much as possible. In this series, no one converted to open surgery. The average operating time was (115.2 ± 44.5) min. Single tract PCNL was performed for 80.97% of the cases, two tracts 13.94%, three tracts 4.65%, and four tracts 0.44%. The upper, middle, and lower calix tracts accounted for 12.1, 63.0, and 24.9%, of procedures, respectively. Stone-free rate was 85.7% overall, 92.2% for single calculus (83/90), and 72.9% for staghorn calculi (78/107). Major postoperative complications occurred in 3.3% of the cases. This study demonstrated PCNL in a semisupine position is an effective alternative for treating renal calculi, which combines the advantages of PCNL in a prone position, and PCNL in a supine position. The semisupine position allows easier irrigation of stone fragments, is more comfortable for the patient, and facilitates monitoring of anesthesia.     

The impact of morbid obesity, pneumoperitoneum, and posture on respiratory system mechanics and oxygenation during laparoscopy

We studied the effect of morbid obesity, 20 mm Hg pneumoperitoneum, and body posture (30 degrees head down and 30 degrees head up) on respiratory system mechanics, oxygenation, and ventilation during laparoscopy. We hypothesized that insufflation of the abdomen with CO(2) during laparoscopy would produce more impairment of respiratory system mechanics and gas exchange in the morbidly obese than in patients of normal weight. The static respiratory system compliance and inspiratory resistance were computed by using a Servo Screen pulmonary monitor. A continuous blood gas monitor was used to monitor real-time PaCO(2) and PaO(2), and the ETCO(2) was recorded by mass spectrometry. Static compliance was 30% lower and inspiratory resistance 68% higher in morbidly obese supine anesthetized patients compared with normal-weight patients. Whereas body posture (head down and head up) did not induce additional large alterations in respiratory mechanics, pneumoperitoneum caused a significant decrease in static respiratory system compliance and an increase in inspiratory resistance. These changes in the mechanics of breathing were not associated with changes in the alveolar-to-arterial oxygen tension difference, which was larger in morbidly obese patients. Before pneumoperitoneum, morbidly obese patients had a larger ventilatory requirement than the normal-weight patients to maintain normocapnia (6.3 +/- 1.4 L/min versus 5.4 +/- 1.9 L/min, respectively; P = 0.02). During pneumoperitoneum, morbidly obese, supine, anesthetized patients had less efficient ventilation: a 100-mL increase of tidal volume reduced PaCO(2) on average by 5.3 mm Hg in normal-weight patients and by 3.6 mm Hg in morbidly obese patients (P = 0.02). In conclusion, respiratory mechanics during laparoscopy are affected by obesity and pneumoperitoneum but vary little with body position. The PaO(2) was adversely affected only by increased body weight. IMPLICATIONS: Morbid obesity significantly decreases respiratory system compliance and increases inspiratory resistance. Increased body weight, and not altered mechanics of breathing, was associated with worse PaO(2) during laparoscopy.     

斜仰卧位经皮肾镜取石术在高龄高危肾结石患者中的应用

目的探讨斜仰卧位经皮肾镜取石术治疗高龄高危肾结石患者的安全性及疗效。方法回顾性分析2007年3月至2011年10月,采用斜仰卧位经皮肾镜取石术治疗32例高龄高危肾结石患者资料。术前积极处理合并症,将手术风险降低至最低限度后行斜仰卧位经皮肾镜取石术。结果本组32例手术均顺利。手术时间12～75min,平均45min。住院时间平均8.6d,一期手术结石取尽26例,3例行体外冲击波碎石,3例行二期手术取石,结石总取净率87.5%。术中、术后无大出血、周围脏器损伤等严重并发症发生,术中未见肾盂输尿管穿孔,仅1例需术后输血,5例患者术后发热。结论斜仰卧位经皮肾镜取石术具有创伤小安全性等高优点,尤其适用于高龄、高危肾结石患者。     

Lower pole stones: prone PCNL versus supine PCNL in the International Cooperation in Endourology (ICE) group experience

Purpose

To assess efficacy and safety of prone- and supine percutaneous nephrolithotomy (PCNL) for the treatment of lower pole kidney stones.

Methods

Data from patients affected by lower pole kidney stones and treated with PCNL between December 2005 and August 2010 were collected retrospectively by seven referral centres. Variables analysed included patient demographics, clinical and surgical characteristics, stone-free rates (SFR) and complications. Statistical analysis was conducted to compare the differences for SFRs and complication rates between prone- and supine PCNL.

Results

One hundred seventeen patients underwent PCNL (mean stone size: 19.5 mm) for stones harboured only in the lower renal pole (single stone: 53.6 %; multiple stones: 46.4 %). A higher proportion of patients with ASA score ≥ 3 and harbouring multiple lower pole stones were treated with supine PCNL (5.8 vs. 23.1 %; p = 0.0001, and 25 vs. 81.5 %; p = 0.0001, respectively, for prone- and supine PCNL). One-month SFR was 88.9 %; an auxiliary procedure was needed in 6 patients; the 3-month SFR was 90.2 %. There were 9 post-operative major complications (7.7 %). No differences were observed in terms of 1- and 3-month SFRs (90.4 vs. 87.7 %; p = 0.64; 92.3 vs. 89.2 %; p = 0.4) and complication rates (7.6 vs. 7.7 %; p = 0.83) when comparing prone- versus supine PCNL, respectively.

Conclusions

The results confirm the high success rate and relatively low morbidity of modern PCNL for lower pole stones, regardless the position used. Supine PCNL was more frequently offered in case of patients at higher ASA score and in case of multiple lower pole stones.     

Valdivia supine position as the best option for percutaneous surgery of renal calculi in morbidly obese patients

IntroductionTreatment of the morbidly obese patient with symptomatic renal calculi is an interesting urological challenge. Extracorporeal shock wave lithotripsy is frequently not possible for several reasons, and many urological centers match these patients as one of the residual indications for open surgery of kidney lithiasis.Material and methodTwo patients with body mass index more than 50 k/m2 and symptomatic kidney stones were treated with percutaneous nephrolithotomy in the supine position described by Valdivia (slightly lateralized supine decubitus). Standard instrumentation for percutaneous surgery and the semi-rigid ureteroscopy were used, through an Amplatz sheath proximally transfixed with a polypropylene stitch, so to avoid its lost under the fatty skin. Both patients were rendered stone-free without significant morbidity.DiscussionThe advantages of Valdivia position in those patients are clear, both for the commodity of the surgical team, -because time may be spared and help needed to mobilized the patient is less-, as well as for what concerns to the anesthesia, because cardio-respiratory restrictions created by a general anesthesia in prone are greater and more severe in the obese patient. This position seems to be more suitable than other ones recommended for percutaneous nephrolithotomy in the obese patients, such as prone decubitus on a surgical saddle, or lateral decubitus position, that may compromise the radiological control of the operation.     

Effects of the beach chair position, positive end-expiratory pressure, and pneumoperitoneum on respiratory function in morbidly obese patients during anesthesia and paralysis

BACKGROUND: The authors studied the effects of the beach chair (BC) position, 10 cm H2O positive end-expiratory pressure (PEEP), and pneumoperitoneum on respiratory function in morbidly obese patients undergoing laparoscopic gastric banding. METHODS: The authors studied 20 patients (body mass index 42 +/- 5 kg/m2) during the supine and BC positions, before and after pneumoperitoneum was instituted (13.6 +/- 1.2 mmHg). PEEP was applied during each combination of position and pneumoperitoneum. The authors measured elastance (E,rs) of the respiratory system, end-expiratory lung volume (helium technique), and arterial oxygen tension. Pressure-volume curves were also taken (occlusion technique). Patients were paralyzed during total intravenous anesthesia. Tidal volume (10.5 +/- 1 ml/kg ideal body weight) and respiratory rate (11 +/- 1 breaths/min) were kept constant throughout. RESULTS: In the supine position, respiratory function was abnormal: E,rs was 21.71 +/- 5.26 cm H2O/l, and end-expiratory lung volume was 0.46 +/- 0.1 l. Both the BC position and PEEP improved E,rs (P < 0.01). End-expiratory lung volume almost doubled (0.83 +/- 0.3 and 0.85 +/- 0.3 l, BC and PEEP, respectively; P < 0.01 vs. supine zero end-expiratory pressure), with no evidence of lung recruitment (0.04 +/- 0.1 l in the supine and 0.07 +/- 0.2 in the BC position). PEEP was associated with higher airway pressures than the BC position (22.1 +/- 2.01 vs. 13.8 +/- 1.8 cm H2O; P < 0.01). Pneumoperitoneum further worsened E,rs (31.59 +/- 6.73; P < 0.01) and end-expiratory lung volume (0.35 +/- 0.1 l; P < 0.01). Changes of lung volume correlated with changes of oxygenation (linear regression, R2 = 0.524, P < 0.001) so that during pneumoperitoneum, only the combination of the BC position and PEEP improved oxygenation. CONCLUSIONS: The BC position and PEEP counteracted the major derangements of respiratory function produced by anesthesia and paralysis. During pneumoperitoneum, only the combination of the two maneuvers improved oxygenation.     

斜仰截石位下经皮肾镜取石术的临床研究

目的 研究斜仰截石位经皮肾镜取石术( percutaneous nephrolithotomy,PCNL)治疗肾和输尿管上段结石的临床价值. 方法 采用斜仰截石位行PCNL治疗肾输尿管结石患者68例,其中肾结石28例,输尿管上段结石40例.结石最大径平均(2.1 ±1.6) cm. 结果 本组68例患者均手术成功,无一例中转开放手术.采用单通道64例,双通道4例.平均手术时间(88.0 ±36.5) min,术中平均出血量(150.0±70.5) ml.一次性结石清除率为89.7％(61/68),残留结石7例,其中4例二期手术取尽结石,3例行ESWL治疗.术后严重出血3例,行输血治疗;高热2例,予敏感抗生素治疗后痊愈.无胸膜、结肠等腹腔脏器损伤等并发症发生. 结论 斜仰截石位行PCNL术治疗肾输尿管结石安全有效,患者耐受性好.     

Prevention of atelectasis formation during the induction of general anesthesia in morbidly obese patients

Atelectasis caused by general anesthesia is increased in morbidly obese patients. We have shown that application of positive end-expiratory pressure (PEEP) during the induction of anesthesia prevents atelectasis formation in nonobese patients. We therefore studied the efficacy of PEEP in morbidly obese patients to prevent atelectasis. Twenty-three adult morbidly obese patients (body mass index >35 kg/m(2)) were randomly assigned to one of two groups. In the PEEP group, patients breathed 100% oxygen (5 min) with a continuous positive airway pressure of 10 cm H(2)O and, after the induction, mechanical ventilation via a face mask with a PEEP of 10 cm H(2)O. In the control group, the same induction was applied but without continuous positive airway pressure or PEEP. Atelectasis, determined by computed tomography, and blood gas analysis were measured twice: before the induction and directly after intubation. After endotracheal intubation, patients of the control group showed an increase in the amount of atelectasis, which was much larger than in the PEEP group (10.4% +/- 4.8% in control group versus 1.7% +/- 1.3% in PEEP group; P < 0.001). After intubation with a fraction of inspired oxygen of 1.0, PaO(2) was significantly higher in the PEEP group compared with the control group (457 +/- 130 mm Hg versus 315 +/- 100 mm Hg, respectively; P = 0.035) We conclude that in morbidly obese patients, atelectasis formation is largely prevented by PEEP applied during the anesthetic induction and is associated with a better oxygenation. IMPLICATIONS: Application of positive end-expiratory pressure during induction of general anesthesia in morbidly obese patients prevents atelectasis formation and improves oxygenation. Therefore, this technique should be considered for anesthesia induction in morbidly obese patients.     

Bilateral renal calculi: assessment of staged v synchronous percutaneous nephrolithotomy

BACKGROUND AND PURPOSE: Percutaneous stone removal has replaced open renal surgery and has become the treatment of choice for large or complex renal calculi. However, patients with large bilateral stone burdens still present a challenge. Simultaneous bilateral percutaneous nephrolithotomy (PCNL) has been demonstrated to be a well-tolerated, safe, cost-effective, and expeditious treatment. We present what is, to our knowledge, the first large retrospective series comparing synchronous and asynchronous bilateral PCNL. PATIENTS AND METHODS: A chart review was performed on 26 patients undergoing 57 PCNLs for bilateral renal calculi over a 7-year period. Seven patients received synchronous PCNL (same anesthesia; Group 1), and 19 patients underwent asynchronous PNL (procedures separated by 1-3 months; Group 2). Complete surgical and hospital records were available on all patients. The average stone burden for Group 1 was 8.03 cm(2) on the left and 9.18 cm(2) on the right v 10.1 cm(2) on the left and 14.23 cm(2) on the right for Group 2 (P> 0.05). Variables of interest included anesthesia time, operative time, blood loss, transfusion rates, length of hospital stay, and complication rates. Each variable was evaluated per operation and per renal unit. Follow-up imaging with stone assessment was available on 20 patients. RESULTS: Group 1 required 1.14 access tracts per renal unit to attempt complete clearance of the targeted stones v 1.88 tracts per renal unit in Group 2 (P> 0.05). The average operative time per renal unit was significantly less in Group 1 (83 minutes) than in Group 2 (168.5 minutes) (P< 0.0001), as was blood loss (178.5 mL v 307.4 mL, respectively; P= 0.02). However, blood loss per operation was similar at 357 mL in Group 1 and 282 mL in Group 2. Comparable transfusion rates of 28.6% and 36.8%, respectively, were noted. Forty percent of the patients in Group 1 were completely stone free compared with 36% of the patients in Group 2; however, an additional 50% and 57%, respectively, had residual stone burden <4 mm (P> 0.05). Complications occurred in 2 of 7 operations (28%) in Group 1 and 8 of 42 operations (19%) in Group 2. The total length of hospital stay was nearly doubled for patients undergoing staged PCNL (P= 0.0005). CONCLUSIONS: These results demonstrate similar stone-free rates, blood loss per operation, and transfusion rates for simultaneous and staged bilateral PCNL. The reduced total operative time, hospital stay, and total blood loss, along with the requirement for only one anesthesia, makes synchronous bilateral PCNL an attractive option for select individuals. However, in patients with larger, less easily accessible stones, excessive bleeding may be encountered more frequently on the first side, thereby delaying management of the second side to a later date. Synchronous bilateral PCNL should be considered in patients in whom the first stage of stone removal is accomplished quickly and safely.     

截石位微创经皮肾镜联合逆行输尿管镜治疗上尿路疾病

目的探讨截石位微创经皮肾镜联合逆行输尿管镜在处理上尿路疾病中的临床应用价值。方法本组23例中，男15例，女8例。年龄21．69岁，平均（45＋13）岁。23例行腹部平片（KUB）＋静脉肾盂造影（IVU）、超声检查或CT检查：20例为肾结石或合并输尿管结石（其中对侧2例），2例为输尿管多发性结石，1例为腹腔镜膀胱癌根治术＋原位回肠膀胱术后双侧输尿管下端狭窄。肾结石最大径为1．2～3．4cm，输尿管结石长径0．8—1．7cm.23例均伴有肾积水，其中轻度积水7例，中度积水14例，重度积水2例。采用截石位并于患侧腰肋部用水袋垫高，同时进行逆行置管或输尿管镜及PCNL手术。结果本组23例手术均成功，无1例出现结肠损伤等严重并发症。20例。肾结石患者中一期取净结石17例，结石取净率达85％。所有输尿管结石均一期处理干净。输尿管下端狭窄者采用顺行与逆行相结合扩张成功并留置8F双J管。结论截石位行微创经皮肾镜术联合逆行输尿管镜术方便术者顺行及逆行操作，术中无需变换体位，利于击碎的结石冲出，患者及术者体位舒适，避免呼吸及循环严重并发症，是处理上尿路结石安全、高效、方便的新方法。