Doppler Probe Research Articles

Effect of Normobaric versus Hypobaric Oxygenation on Gaseous Microemboli Removal in a Diffusion Membrane Oxygenator: An In Vitro Comparison

Gaseous microemboli (GME) are an abnormal physiological occurrence during cardiopulmonary bypass and extracorporeal membrane oxygenation (ECMO). Several studies have correlated negative sequelae with exposure to increased amounts of GME. Hypobaric oxygenation is effective at eliminating GME in hollow-fiber microporous membrane oxygenators. However, hollow-fiber diffusion membrane oxygenators, which are commonly used for ECMO, have yet to be validated. The purpose of this study was to determine if hypobaric oxygenation, compared against normobaric oxygenation, can reduce introduced GME when used on diffusion membrane oxygenators. Comparison of a sealed Quadrox-iD with hypobaric sweep gas (.67 atm) vs. an unmodified Quadrox-iD with normal atmospheric sweep gas (1 atm) in terms of GME transmission during continuous air introduction (50 mL/min) in a recirculating in vitro circuit, over a range of flow rates (3.5, 5 L/min) and crystalloid prime temperatures (37°C, 28°C, and 18°C). GME were measured using three EDAC Doppler probes positioned pre-oxygenator, post-oxygenator, and at the arterial cannula. Hypobaric oxygenation vs. normobaric oxygenation significantly reduced hollow-fiber diffusion membrane oxygenator GME transmission at all combination of pump flows and temperatures. There was further significant reduction in GME count between the oxygenator outlet and at the arterial cannula. Hypobaric oxygenation used on hollow-fiber diffusion membrane oxygenators can further reduce GME compared to normobaric oxygenation. This technique may be a safe approach to eliminate GME during ECMO.

Preliminary experience with the novel laparoendoscopic single-site extraperitoneal (LESS-EP) varicocelectomy

Minimally invasive varicocelectomy offers improved peri-operative pain and cosmesis as compared to standard microsurgical approaches(1-3).While standard multi-port laparoscopic varicocelectomy yields equivalent outcomes in terms of efficacy(4), an extraperitoneal approach decreases risk of bowel injury or post-operative gastrointestinal symptoms.(5, 6) We herein describe our initial results with an extraperitoneal approach coupled to single port laparoscopy (LESS-ep). We performed an IRB approved retrospective chart review of patients undergoing varicocelectomy (CPT codes 55550, 55530) at our center with a single surgeon between 3/1/2013 to 3/1/2016. Microsurgical and laparoscopic varicocelectomies were performed in standard previously described fashion. LESS-EP was performed as follows; a 2 cm infra umbilical incision was made. The anterior rectus sheath was anchored with 0 Vicryl sutures in parallel then divided. The rectus muscle was dissected laterally thereby exposing the posterior rectus sheath. The extraperitoneal space was developed bluntly using a balloon dissector under direct vision, and then the GelPort Mini Advanced Access (Applied Medical) was affixed. The GelPort was prepared with three trocars positioned in a tripod configuration as well as the Doppler probe. Varicocelectomy was performed under direct vision with a 5mm 30 degree bariatric laparoscope with dissection at the level of the internal inguinal ring. Manual chart review included patient history, lab values, and operative data. Data were analyzed with Student’s T-test. Of the 75 patients in our cohort, 32 underwent microscopic varicocelectomy, 18 had a standard laparoscopic varicocelectomy, and 25 underwent a less-ep repair. The average age was 39. There were no intraoperative complications in any group, nor EBL greater than 25 cc’s. There was no difference in operative times between groups (97 vs 84 vs 101 minutes, respectively; p=0.43). There were no instances of recurrent varicocele. In the LESS-EP cohort, there were no complications within 30 days; 2 patients received treatment for presumed epididymitis within the first 6 months of surgery. No statistically significant difference in change in sperm parameters was identified. Of 27 concomitant surgeries performed, all inguinal hernia repairs were performed with a standard laparoscopic technique and testicular sperm extraction was performed via microsurgical approach. LESS-EP is a novel approach to varicocelectomy. We have found LESS-EP to be comparable to established methods in terms of safety, operative time and efficacy. It may be most appropriate in patients with bilateral disease or prior inguinal surgery. A microsurgical approach may be most apropos in patients with unilateral disease and no prior groin surgery, and as well for whom concomitant surgeries are not required. Further study is ongoing to assess patient outcomes including long term improvement in semen analysis and pregnancy rates.

Utilidad de la monitorización de los colgajos microquirúrgicos

AimTo evaluate Doppler probe to assure the flow through the anastomoses at free flaps used in head and neck surgery. Material and methodDescriptive prospective series, of every patient that receive a free flap reconstruction at Clinica Alemana between March 2013 and March 2015, in which a Doppler monitor (Coock® Swartz Doppler probe) on the arterial anastomoses was used. Results20 patients with free flaps were recorded. 10 radial flaps, 7 fibulas (4 with a skin paddle and 3 without), 2 antero lateral thigh flaps and 1 abdominis rectus flap. 6 reexplorations were done. In one case the suspicion was clinical, with change in the Doppler signal, 4 patients just clinical suspicion and 1 just because a change in the Doppler signal. The findings were flap edema in 1 patient and 5 hematomas. We didn’t loss any flap. The Doppler monitor was used for an average of 9.5 days. ConclusionThe Doppler monitor doesn’t replace the clinical observation but represents another tool for the decision making during the post operative period in this kind of head and neck reconstructions.

Comparison of esophageal Doppler and plethysmographic variability index to guide intraoperative fluid therapy for low-risk patients undergoing colorectal surgery

Study objectiveThis study aims to investigate if there is equivalence in volumes of fluid administered when intravenous fluid therapy is guided by Pleth Variability Index (PVI) compared to the established technology of esophageal Doppler in low-risk patients undergoing major colorectal surgery. DesignRandomized controlled trial. SettingOperating room. PatientsForty low-risk patients undergoing elective colorectal surgery. InterventionPatients were monitored by esophageal Doppler and PVI probes and were randomized to have fluid therapy directed by using one of these technologies, with 250 mL boluses of colloid to maintain a maximal stroke volume, or a PVI of less than 14%. MeasurementsAbsolute volumes of fluid volumes given intraoperatively were measured as were 24 hours fluid volumes. Perioperative measurements of lactate and base excess were recorded as were postoperative complications. Main resultThere was no significant difference between PVI and esophageal Doppler groups in mean total fluid administered (1286 vs 1520 mL, P=.300) or mean intraoperative fluid balance (+839 v+1145 mL, P=.150). ConclusionsPVI offers an entirely non-invasive alternative for goal-directed fluid therapy in this group of patients.

Multimodal Navigation in Endoscopic Transsphenoidal Resection of Pituitary Tumors Using Image-Based Vascular and Cranial Nerve Segmentation: A Prospective Validation Study

Transsphenoidal surgery (TSS) is the most common approach for the treatment of pituitary tumors. However, misdirection, vascular damage, intraoperative cerebrospinal fluid leakage, and optic nerve injuries are all well-known complications, and the risk of adverse events is more likely in less-experienced hands. This prospective study was conducted to validate the accuracy of image-based segmentation coupled with neuronavigation in localizing neurovascular structures during TSS. Twenty-five patients with a pituitary tumor underwent preoperative 3-T magnetic resonance imaging (MRI), and MRI images loaded into the navigation platform were used for segmentation and preoperative planning. After patient registration and subsequent surgical exposure, each segmented neural or vascular element was validated by manual placement of the navigation probe or Doppler probe on or as close as possible to the target. Preoperative segmentation of the internal carotid artery and cavernous sinus matched with the intraoperative endoscopic and micro-Doppler findings in all cases. Excellent correspondence between image-based segmentation and the endoscopic view was also evident at the surface of the tumor and at the tumor-normal gland interfaces. Image guidance assisted the surgeons in localizing the optic nerve and chiasm in 64% of cases. The mean accuracy of the measurements was 1.20 ± 0.21 mm. Image-based preoperative vascular andneural element segmentation, especially with 3-dimensional reconstruction, is highly informative preoperatively and potentially could assist less-experienced neurosurgeons in preventing vascular and neural injury during TSS. In addition, the accuracy found in this study is comparable to previously reported neuronavigation measurements. This preliminary study is encouraging for future prospective intraoperative validation with larger numbers of patients.

The Influence Of Time On Determining Blood Flow Restriction Pressure

It has been recommended that the pressure applied for blood flow restriction (BFR) should be made relative to the individual. It has been suggested that this pressure should be based, to some degree, on limb circumference and brachial systolic blood pressure (bSBP) as they explain a large amount of unique variance in the arterial occlusion pressure. It has long been known that blood pressure does oscillate throughout the day, however, the impact of this blood pressure change on the arterial occlusion measurement had not been previously investigated. PURPOSE: To investigate the arterial occlusion measurement within and between days at two distinct time points. We hypothesized that the arterial occlusion measurement would oscillate within the same day. METHODS: Twenty two participants [age: 24 (3) years] came to the laboratory a total of four times at 08:00 and 18:00 hours on two separate days, 48 hours apart. During the first visit only, each participant had height and body mass assessed. In all four visits the participants had their arm circumference, resting bSBP, resting bDBP, and standing arterial occlusion pressure measured in that order. Arterial occlusion (5 cm wide nylon cuff) was determined by the cessation of the pulse from the radial artery using a Doppler probe. A one-way repeated measures ANOVA with a between subject factor of sex was used to determine differences. All data are presented as means and standard deviations. The alpha level was set at p≤0.05. RESULTS: A time effect was found for arterial occlusion (p=0.009), but there was no sex by time interaction. Follow up tests revealed that all visits [Morning Day 1: 138(16); Evening Day 1: 139(17); Evening Day 2: 138 (14) mmHg] were different from the second morning visit [132 (14) mmHg, p<0.05]. In addition, a time effect was found for bSBP (p=0.017), but there was no sex by time interaction. The post-hoc test revealed that all visits were different from the second morning visit. No differences were observed across time for arm circumference or bDBP. CONCLUSIONS: Previous multiple-visit BFR studies have based the applied pressure for all visits off of a single arterial occlusion measurement. Our findings suggest that this arterial occlusion pressure is affected by temporal progression which may affect the subsequent relative occlusion pressures.

The Influence of Cuff Width and Sex on Arterial Occlusion

PURPOSE: To examine differences in arterial occlusion pressure (AOP) of the upper arm when applying cuff widths (5 cm, 10 cm, and 12 cm) commonly used in blood flow restriction (BFR) research. This study also examined how individual predictors of AOP changed across cuff widths. METHODS: Two hundred forty-nine (102 males and 147 females) participants visited the laboratory once. Height, body mass, arm length, and arm circumference were assessed. Following a 10-minute rest, brachial blood pressure was measured (systolic = bSBP and diastolic = bDBP). With a rest period of 5-minutes before each measurement, standing AOP was determined on the right arm for each cuff (counterbalanced) using a Doppler probe placed at the radial artery. Hierarchical linear regression was used to determine which predictors explained the most unique variance in AOP for each cuff width. To examine sex differences in AOP across cuff widths, a repeated measures ANOVA was used with a between subject factor of sex. If an interaction was found, a Fishers LSD test identified differences between cuff widths within each sex, and independent t-tests were used to examine differences for sex within each cuff width. Effect sizes were determined by calculating Cohen’s d. Data is presented as mean (standard deviation). RESULTS: Occlusion pressure was different across cuff widths (p < 0.001). The 5 cm wide cuff required the greatest pressure [145 (19) mmHg], followed by the 10 cm [123 (13) mmHg], and 12 cm [120 (12) mmHg] wide cuffs. A model of arm circumference, bSBP, arm length, bDBP, and sex explained the most variance in AOP for all three cuff widths (5 cm, R2 = 0.651; 10 cm, R2 = 0.570; 12 cm, R2 = 0.557). However, arm circumference always explained the most unique variance in AOP (5 cm, Part = .554; 10 cm, Part = .419; 12 cm, Part = .406). Differences in AOP existed between sexes for the 5 cm [males 149 (19) vs females 142 (19) mmHg, p = 0.003, d = 0.36], 10 cm [males 127 (13) vs females 121 (13) mmHg, p = 0.002, d = 0.46], and 12 cm [males 122 (12) vs females 118 (12) mmHg, p = 0.009, d = 0.33] wide cuffs. CONCLUSIONS: The cuff width used for BFR has a significant impact on AOP in the upper arm. Future studies should acknowledge this, and ensure cuff width is reported. Further, individual differences, primarily arm circumference, should be accounted for when applying relative inflation pressures.

Postoperative monitoring of free flap reconstruction: A comparison of external Doppler ultrasonography and the implantable Doppler probe

Hypothesis The time to detection of vascular compromise and the postoperative time to reexploration are shorter using the implantable Doppler (ID) probe, thereby resulting in earlier surgical reexploration and a higher flap salvage rate. Methods A single-centre experience with 176 consecutive free flap reconstructions in 167 patients from 2000 to 2008 in a university-based teaching hospital by retrospective chart review is presented. Results There was a significant difference in overall flap survival (ID 98.0%, external Doppler [ED] 89.3%) and total flap loss (ID 2.0%, ED 10.7%) between the two groups (P=0.03). The difference in flap salvage rate was not significant (ID 90.9%, ED 63.6%; P=0.068). The false-positive (ID 0%, ED 3%; P=0.18) and false-negative rates (ID 0.0%, ED 4.5%; P=1.0) were not significantly different. There was also a lower median postoperative time to reexploration for the ID group, from 48 h to one week after initial surgery (ID 74.5 h, ED 136.8 h; P=0.05). Conclusion The present analysis revealed a potential benefit for the ID probe in the postoperative monitoring of free tissue transfers.

Deciphering the Sensitivity and Specificity of the Implantable Doppler Probe in Free Flap Monitoring.

The efficacy of implantable Doppler probes remains an area of considerable debate. This study aims to decipher its sensitivity and specificity for free flap monitoring. A retrospective review of all free flaps with an implantable Doppler probe was performed between 2000 and 2012. A Cook-Swartz implantable Doppler probe was used in 439 patients (head and neck, n = 364; breast, n = 53; extremity, n = 22), and demonstrated equivalent sensitivity and specificity between flap types. The overall sensitivity and specificity were 77.8 percent and 88.4 percent, respectively. The artery was monitored in 267 patients, compared to venous monitoring in 101 patients, and in 71 patients both the artery and vein were monitored. Arterial monitoring had significantly greater specificity than venous monitoring, (94.2 percent versus 74.0 percent; p < 0.001), but no benefit was found in monitoring both the artery and the vein. Venous monitoring was significantly associated with reoperation (OR, 3.17; 95 percent CI, 1.70 to 5.91; p = 0.0003). There were 284 flaps that had a monitoring segment in addition to the implantable Doppler probe that significantly increased overall specificity for microvascular complications (OR, 17.71; 95 percent CI, 3.39 to 92.23; p = 0.0006). The specificity (90.5 percent versus 84.8 percent) and sensitivity (80.0 percent versus 66.7 percent) were significantly higher for clinically monitored flaps. The take-back rate was 13.0 percent, with positive findings in 59.6 percent, and 5.2 percent total flap loss. The use of implantable Doppler probes has high sensitivity and specificity for buried free flaps despite positive findings in less than 60 percent of take-backs. Monitoring the artery is recommended, but clinical examination remains the gold standard for flap monitoring. Diagnostic, IV.

The Influence of Cuff Width, Sex, and Race on Arterial Occlusion: Implications for Blood Flow Restriction Research.

The main aim of this study was to examine differences in upper arm arterial occlusion pressure (AOP) between three different cuff widths and how individual characteristics influence this. Additional aims of the study were to investigate differences in AOP due to sex and race and to create regression equations that estimate AOP for each cuff width. Two hundred and forty nine participants (males n=102; females n=147) visited the laboratory once for measurement of arm length, arm circumference, and resting brachial systolic (bSBP) and diastolic blood pressure (bDBP). Next, each cuff was applied to the upper arm and inflated until a Doppler probe placed at the radial artery no longer detected blood flow. The minimum inflation pressure that caused cessation of blood flow was determined to be the AOP. Differences in AOP were observed between cuff widths (p<0.001). The 5-cm-wide cuff required the greatest inflation pressure [145 (19)mmHg], followed by the 10cm [123 (13)mmHg], and 12-cm-wide cuff [120 (12)mmHg]. A model encompassing arm circumference, bSBP, arm length, bDBP, and sex explained the most variance in AOP for each cuff (5cm, R (2)=0.651; 10cm, R (2)=0.570; 12cm, R (2)=0.557). However, arm circumference explained the most unique variance for each cuff. When separated by sex, males required greater pressures. Additionally, after controlling for sex, it was found that non-Hispanic Blacks required greater pressures compared with Whites. The regression equations for each cuff width are as follows: 5cm (mmHg)=2.926 (arm circumference)+1.002 (bSBP)-0.428 (arm length)+0.213 (bDBP)+12.668 (sex)-68.493; 10cm (mmHg)=1.545 (arm circumference)+0.722 (bSBP)-0.235 (arm length)+0.205 (bDBP)+6.378 (sex)-15.918; 12cm (mmHg)=1.393 (arm circumference)+0.710 (bSBP)-0.294 (arm length)+0.164 (bDBP)+6.419 (sex)-8.752. The AOP is dependent upon cuff width, highlighting the need for authors to report cuff width and consider the impact it has on restriction. Participant characteristics, especially arm circumference, should be considered when applying this blood flow restriction pressure. Lastly, both sex and race have an impact on AOP, although it is not presently known how meaningful this difference is.

Do you mind if I vape? Immediate effects of electronic cigarettes on perfusion in buccal mucosal tissue - a pilot study

The association between smoking and postoperative complications is compounded in patients who have oral and maxillofacial operations by an additional local effect, and patients often continue to smoke after operation despite advice to stop. Recent studies have suggested that nicotine may reduce inflammation and improve angiogenesis, so topical application may be beneficial for smokers. The electronic cigarette is increasing in popularity and more patients ask whether they can vape after operation. We investigated the effect of electronic cigarettes (of which half contained nicotine and half did not) on blood flow in the buccal mucosa in 10 volunteers immediately after vaping. Smokers were excluded as this was considered an additional variable in a small pilot study and our Trust has a no-smoking policy. After vaping for 5minutes, capillary blood flow was measured in the buccal mucosa at 5-minute intervals using a laser Doppler probe, and the results were expressed as arbitrary perfusion units. There was a wide variation in results and a small but significant rise (p=0.008) as a result of nicotine vaping, but these fell to the same levels as before within 30minutes. Electronic cigarettes may have an effect on blood flow to the oral mucosa, although further studies are needed to show whether they improve healing time after operation. Additional work is also needed to compare them with cigarettes.

The Doppler Effect: A Century from Red Shift to Red Spot.

The development of medical ultrasonography is one of the most pervasively useful advances in medical practice that has occurred in the twentieth century. The technique has many advantages over other imaging technologies, including being almost entirely noninvasive, portable, low cost, and free of ionizing radiation and of known harmful effects—safe enough that it can be used for developing fetuses. How medical ultrasound evolved from related technologies is well described in the superb article accompanying this introduction [1]. I would like to focus on a related invention in this introduction, the endoscopic Doppler probe, which has positively impacted gastrointestinal endoscopy as a result of a discovery by Johann Andreas Doppler originally published in 1842 [2], which created a paradigm shift that revolutionized fields as diverse as astronomy, meteorology, cosmology, and medicine. In its simplest conceptual form, the Doppler effect describes how the relative motion of the source and the sensor alters the frequency of electromagnetic or sound waves. Everyone has experienced the increasing pitch of an approaching train or auto sounding its horn, which suddenly lowers as it passes, due to the compression of the sound waves produced by the train’s horn as it approaches a stationary listener followed by expansion as the train or car passes and recedes. Although Doppler was correct in theory when he hypothesized that the apparent color of double stars shifts according to their velocity relative to the Earth’s, the stars’ color shifts in his example were due to other factors. It required an experiment in 1845 in which the apparent pitch of trumpeters on a moving railway flatcar shifted to stationary observers that made believers out of the skeptics [3]. Like all paradigm shifts of great magnitude, Doppler attracted disbelievers and doubters, notably Josef Petzval, who questioned the veracity of Doppler’s theory [3]. In any case, dying at age 53, likely due to tuberculosis, Doppler, although showered with academic honors, never lived to experience the full impact of his findings. Although many nineteenth-century scientists described red shifts of ‘‘nearby’’ stars, it was not until 1912 that the Doppler shift of the nebulae (galaxies) was described by Slipher [4], setting the stage for Edwin Hubbell in 1932 to theorize that the universe is expanding [5], enabling physicists to calculate the Hubbell constant which in turn enables calculation of astounding and stupendous dimensions and velocities such as the size of the universe, its rate of expansion, and its age. The Doppler shift has also enhanced weather forecasting in that it can precisely identify the location, the direction, and the magnitude of winds and of precipitation and RADARS (radio direction and ranging), some features of which are based on the Doppler shift. The most interest, however, for our readers is of course the medical application of the Doppler effect, which has fallen almost exclusively into blood flow measurements. Dussik [6], who is considered to be the founder of medical ultrasonography, reported the use of the Doppler effect in ultrasound measurements, followed in 1955 by Satomura, who reported that the technology enabled measurement of cardiac valvular function [7]. Franklin et al. [8] reported that the Doppler shift correlated with blood flow. Early use of a Doppler flowprobe for measurements in the mesenteric vasculature was reported in the mid-1970s [9, & Jonathan D. Kaunitz jake@ucla.edu

Non-Invasive Imaging of Preoperative Mapping of Superficial Veins in Free Flap Breast Reconstruction.

Non-Invasive Imaging of Preoperative Mapping of Superficial Veins in Free Flap Breast Reconstruction.

Neurosurgical Treatment of Acromegaly.

Surgical removal of as much tumor mass as possible is usually considered the first step of treatment in acromegaly, unless the patients are unfit for surgery or refuse an operation. To date, in almost all cases, minimally invasive, transsphenoidal microscopic or endoscopic approaches are used. Whether a curative approach is feasible or a debulking procedure is planned, can be anticipated on the basis of preoperative magnetic resonance imaging. It mostly depends on localization, size, and the invasive character of the lesion. The surgical results depend on tumor-related factors such as size, extension, the presence or absence of invasion, and the magnitude of IGF-1 and growth hormone oversecretion, respectively. However, even surgeon-related factors such as experience and case load of the centers have been shown to strongly affect surgical results and complication rates. A reoperation can be considered at various stages in the treatment algorithm. There are several new technical gadgets which might aid in the surgical procedure: navigation, the Doppler probe, and variants of intraoperative imaging.

Postoperative monitoring of free flap reconstruction: A comparison of external Doppler ultrasonography and the implantable Doppler probe.

The time to detection of vascular compromise and the postoperative time to re-exploration are shorter using the implantable Doppler (ID) probe, thereby resulting in earlier surgical re-exploration and a higher flap salvage rate. A single-centre experience with 176 consecutive free flap reconstructions in 167 patients from 2000 to 2008 in a university-based teaching hospital by retrospective chart review is presented. There was a significant difference in overall flap survival (ID 98.0%, external Doppler [ED] 89.3%) and total flap loss (ID 2.0%, ED 10.7%) between the two groups (P=0.03). The difference in flap salvage rate was not significant (ID 90.9%, ED 63.6%; P=0.068). The false-positive (ID 0%, ED 3%; P=0.18) and false-negative rates (ID 0.0%, ED 4.5%; P=1.0) were not significantly different. There was also a lower median postoperative time to re-exploration for the ID group, from 48 h to one week after initial surgery (ID 74.5 h, ED 136.8 h; P=0.05). The present analysis revealed a potential benefit for the ID probe in the postoperative monitoring of free tissue transfers.

The Auscultation of a Carbon Dioxide Embolization Event during Endoscopic Vein Harvest.

Endoscopic vein harvest in preparation for coronary artery bypass surgery has become a preferred method of procuring saphenous vein. Several case reports have documented carbon dioxide (CO2) embolization with this procedure as well as CO2 embolization during other laparoscopic surgeries (Markar et al., 2010). Although uncommon, the potential for CO2 entrainment through an open vein or through absorption by vascular structures exists and should be recognized (Lin et al., 2003). We report a case of CO2 embolization during EVH for a 77-year-old patient who underwent CABG that was identified early by the cardiac surgeon through the indirect auscultation of a mill-wheel murmur after the pericardium was opened. This may be the first reported case of a murmur related to air emboli identified without the use of a precordial Doppler probe or a stethoscope. This diagnosis was further supported by TEE before systemic hypotension or cardiovascular collapse occurred.

The use of intraoperative Doppler ultrasound in endoscopic transsphenoidal surgery

Doppler ultrasound (DUS) has been widely used in neurosurgical practice to diagnose various cerebrovascular diseases. This technique is used in transsphenoidal surgery to identify the localization of intracranial arteries when making an approach or during tumor resection. To identify the cavernous segment of the internal carotid artery (ICA) and/or basilar artery during endoscopic transsphenoidal surgery, we used a combined device on the basis of a click line curette («Karl Storz») and a 16 MHz Doppler probe (Lassamed). The technique was used in 51 patients during both standard transsphenoidal surgery (23 cases) and transsphenoidal tumor resection through an extended approach (28 cases). Doppler ultrasound was used in different situations: to determine a trajectory of the endonasal transsphenoidal approach in the absence of the normal anatomical landmarks (16 cases), to define the limits of safe resection of a tumor located in the laterosellar region (7), and to implement an extended transsphenoidal endoscopic approach (28). Intraoperative Doppler ultrasound enabled identification of the cavernous segment of the internal carotid artery in 45 cases and the basilar artery in 2 cases; a blood vessel was not found in 4 cases. Injury to the cavernous segment of the internal carotid artery was observed only in 1 case. The use of the described combined device in transsphenoidal surgery turned Doppler ultrasound into an important and useful technique for visualization of the ICA within the tumor stroma as well as in the case of the changed skull base anatomy. Its use facilitates manipulations in a deep and narrow wound and enables inspection of the entire surface of the operative field in various planes, thereby surgery becomes safer due to the possibility of maximum investigation of the operative field.

Management of Sacral Pressure Sore by Clinically Isolated Superior Gluteal Artery Perforator-based Fasciocutaneus Flap in Patients with Spinal Cord Injury

Abstract Prolong confinement to bed in spinal injury patients imparts constant pressure on bony prominences resulting impairment of blood flow to local tissue. Constant pressure of 2 hours or more produces irreversible changes leading to tissue necrosis and development of pressure sore. Sacrum encounters highest pressure in supine position and is the commonest site of pressure sore in spinal cord injury patients followed by trochanter and heel. Objective of the study Observation on management of sacral pressure sore by superior gluteal arterial perforatorbased flap using anatomical land marks in the absence of facility of Doppler probe for isolation of superior gluteal arterial perforators. Materials and methods Thirteen patients of spinal cord injury presented with sacral pressure sore were managed surgically using superior gluteal artery perforator-based flap coverage. The location of the artery was identifi ed using anatomical land marks. In 10 patients the flap was heeled uneventfully, one had signifi cant complication with wound dehiscence. Conclusions Management of sacral pressure sore by superior gluteal arterial perforator-based flap using anatomical land marks is a simple and reliable procedure. The learning curve is not that stiff. Sophisticated instruments are not required for this procedure.

Utility of Monitoring Mesenteric Flaps Using a Pencil Doppler Probe after Free Jejunal Transfer

Utility of Monitoring Mesenteric Flaps Using a Pencil Doppler Probe after Free Jejunal Transfer

Low esophageal mucosal blood flow in patients with nutcracker esophagus

Nutcracker esophagus (NE) is characterized by high-amplitude peristaltic esophageal contractions, and these patients often present with symptoms of "angina-like" or noncardiac chest pain. Tissue ischemia is a known cause of visceral pain, and the goal of our present study was to determine whether esophageal wall blood perfusion (EWBP) is reduced in patients with NE. Fourteen normal subjects (mean age 51 yr, 11 men) and 12 patients (mean age 53 yr, 9 men) with NE and noncardiac chest pain were investigated. The EWBP was measured continuously using a custom-designed laser Doppler probe tethered to a Bravo capsule, which anchored it to the esophageal wall. The baseline EWBP in normal subjects was 651 ± 27 perfusion units. In patients with NE, the baseline EWBP was significantly lower than in the normal subjects (451 ± 32 perfusion units). The EWBP decreased after injection of edrophonium (which increases muscle contractions) and increased following sublingual nitroglycerin administration (which relaxes muscle) in normal subjects, as well as in NE patients. Spontaneous pain events during the recording period were often associated with drops in the EWBP. We propose that low EWBP leads to hypoxia of the esophageal tissue, which may be a mechanism of esophageal pain in patients with NE.