Live broadcast of laparoscopic surgery to handheld computers.

BACKGROUND: Thanks to advances in computer power and miniaturization technology, portable electronic devices are now being used to assist physicians with various applications that extend far beyond Web browsing or sending e-mail. Handheld computers are used for electronic medical records, billing, coding, and to enable convenient access to electronic journals for reference purposes. The results of diagnostic investigations, such as laboratory results, study reports, and still radiographic pictures, can also be downloaded into portable devices for later view. Handheld computer technology, combined with wireless protocols and streaming video technology, has the added potential to become a powerful educational tool for medical students and residents. The purpose of this study was to assess the feasibility of transferring multimedia data in real time to a handheld computer via a wireless network and displaying them on the computer screens of clients at remote locations. METHODS: A live laparoscopic splenectomy was transmitted live to eight handheld computers simultaneously through our institution's wireless network. RESULTS: All eight viewers were able to view the procedure and to hear the surgeon's comments throughout the entire duration of the operation. CONCLUSION: Handheld computer technology can play a key role in surgical education by delivering information to surgical residents or students when they are geographically distant from the actual event. Validation of this new technology by conducting clinical research is still needed to determine whether resident physicians or medical students can benefit from the use of handheld computers.

Determinants of competency judgments by experienced laparoscopic surgeons.

BACKGROUND: The definitive criteria for assessing competence remain elusive. In our study, we aimed to identify the determinants of competence assessment used by individual laparoscopic surgeons. METHODS: In a blinded fashion, five laparoscopic surgeons rated 27 subjects on three laparoscopic simulations in four skill categories: clinical judgment, dexterity, serial/simultaneous complexity, and spatial orientation. The raters then assessed overall subject competence for each procedure. Point-biserial correlational analyses and cluster analyses were performed to ascertain the relationships among the various scales. RESULTS: All of the correlations between the skills' ratings and competence judgments were statistically significant ( p <.05). No skill rating was consistently more highly correlated with the competence rating. There were no distinct patterns of correlations for each rater or each procedure. One factor emerged from each cluster analysis of the skills measures. CONCLUSIONS: The results suggest that the four skills scored in the study are highly correlated with each other and are important in determining competence. The cluster analyses revealed that the surgeon raters shared a common perception of competence.

Multimedia article. Laparoscopic Ladd's procedure in two adults: malrotation and the minimally invasive approach.

Malrotation is an intestinal rotation anomaly rarely diagnosed in adults. In the adult patient, obstructing peritoneal bands may lead to nausea and abdominal distention. Familiarity with this presentation as well as the aberrant anatomy associated with the unusual problem facilitates surgical treatment. While the minimally invasive approach requires meticulous dissection due to this abnormal anatomy, laparoscopic treatment does provide the advantages of short convalescence and low morbidity. This video briefly reviews embryologic intestinal development, rotational anomalies and two laparoscopic Ladd's procedures.

Primera encuesta en Internet sobre el síntoma de acidez / First Internet survey on the sympton of acidity

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Evaluating minimally invasive surgery training using low-cost mechanical simulations.

BACKGROUND: The goal of this study was to develop, test, and validate the efficacy of inexpensive mechanical minimally invasive surgery (MIS) model simulations for training faculty, residents, and medical students. We sought to demonstrate that trained and experienced MIS surgeon raters could reliably rate the MIS skills acquired during these simulations. METHODS: We developed three renewable models that represent difficult or challenging segments of laparoscopic procedures; laparoscopic appendectomy (LA), laparoscopic cholecystectomy (LC), and laparoscopic inguinal hernia (LH). We videotaped 10 students, 12 surgical residents, and 1 surgeon receiving training on each of the models and again during their posttraining evaluation session. Five MIS surgeons then assessed the evaluation session performance. For each simulation, we asked them to rate overall competence (COM) and four skills: clinical judgment (respect for tissue) (CJ), dexterity (economy of movement) (DEX), serial/simultaneous complexity (SSC), and spatial orientation (SO). We computed intraclass correlation (ICC) coefficients to determine the extent of agreement (i.e., reliability) among ratings. RESULTS: We obtained ICC values of 0.74, 0.84, and 0.81 for COM ratings on LH, LC, and LA, respectively. We also obtained the following ICC values for the same three models: CJ, 0.75, 0.83, and 0.89; DEX, 0.88, 0.86, and 0.89; SSC, 0.82, 0.82, and 0.82; and SO, 0.86, 0.86, and 0.87, respectively. CONCLUSIONS: We obtained very high reliability of performance ratings for competence and surgical skills using a mechanical simulator. Typically, faculty evaluations of residents in the operating room are much less reliable. In contrast, when faculty members observe residents in a controlled, standardized environment, their ratings can be very reliable.

A canine model of gastroesophageal reflux disease (GERD).

BACKGROUND: Although a variety of antireflux procedures and medications are used to treat gastroesophageal reflux disease (GERD), reliable large-animal models of GERD that can be used to objectively compare the efficacy of these treatments are lacking. METHODS: Esophageal manometry and 24-h gastroesophageal pH monitoring with event data were performed in 18 mongrel dogs with a cervical esophagopexy. We then calculated a modified DeMeester score: The Duke Canine reflux score (DCR). Thereafter, the animals underwent a 4-cm anterior distal esophageal myotomy, incision of the left diaphragmatic crus, and intrathoracic gastric cardiopexy. Postoperative 24-h pH and manometry were obtained 2 weeks later. RESULTS: The postoperative 24-h pH results showed a significant increase in the mean DCR score (5.9 +/- 4.5 vs 84.9 +/- 56.1, p < 0.0002), and manometry indicated a significant decrease in mean lower esophageal sphincter (LES) pressure (7.1 +/- 2.9 vs 3.2 +/- 2.5 mmHg, p < 0.0001). CONCLUSION: This technique reliably creates a canine model of GERD.

Histologic evaluation of fetal brains following maternal pneumoperitoneum.

BACKGROUND: The purpose of this study was to determine if maternal pneumoperitoneum with carbon dioxide (CO2) produces evidence of central nervous system (CNS) injury in preterm fetal guinea pigs. METHODS: Thirty pregnant guinea pigs at gestational day (GD) 45 were assigned at random to one of three treatment groups: anesthesia only, CO2 pneumoperitoneum (5 mmHg), or laparotomy. Dams were killed 3 or 5 days postprocedure and fetal brains (83 total) harvested and fixed for subsequent histopathologic evaluation. For comparative purposes, histologic features of fetal guinea pig brain injury were defined from examination of fetal brains harvested from an additional dam that underwent laparotomy with 20 min of uterine arterial occlusion. RESULTS: Carbon dioxide pneumoperitoneum did not increase maternal/fetal morbidity. No evidence of brain injury was found in fetuses from any of the treatment groups. CONCLUSION: Carbon dioxide pneumoperitoneum at 5 mmHg for 40 min in the pregnant guinea pig does not produce evidence of fetal brain injury.

Laparoscopy and the internet. A surgeon survey.

BACKGROUND: The Internet has become an important new tool for the delivery and acquisition of medical information. METHODS: A 13-item questionnaire designed to collect information on the attitudes and practices of surgeons regarding the use of the Internet as a medical resource was posted on the World Wide Web and also sent via e-mail. RESULTS: Over a 2-month period, 459 surgeons were enrolled in this study. Most of the respondents were identified as male surgeons (96%) between the ages of 31 and 50 years (79.25%). They accessed the Internet mainly from their homes (67.10%) and offices (17%) using 56 Kbps (34.86%) and 33.6 Kbps (21.79%) modems. These participants indicated that they use the Internet to expand their knowledge of general surgery (78.87%), learn more about technologies related to the practice of surgery (74.51%), access the Medline medical database (73.20%), and locate other resources for academic purposes (68%). Approximately half of them said that they favored the use of robotic assist devices in the operating room (53%), and most supported the use of technology for telementoring purposes (78%). Almost 80% professed an interest in video streaming technology applied to surgical education. CONCLUSIONS: This study showed that the Internet is a useful and powerful real-time survey tool that can help us to assess the impact of the World Wide Web and related technologies on surgical education and practice. However, the respondents in this study belong to a biased group that is already familiar with the Internet and computer technology and thus may not be representative of the surgical community as a whole.

Laparoscopic dissecting instruments.

The authors provide an overview of laparoscopic dissecting instruments and discuss early development, surgical options, and special features. End effectors of different shapes and functions are described. A comparison of available energy sources for laparoscopic instruments includes discussion of thermal dissection, ultrasonic dissection, and water-jet dissection. The ergonomic risks and challenges inherent in the use of current laparoscopic instruments are outlined, as well as ergonomic issues for the design of future instruments. New directions that laparoscopic instrumentation may take are considered in connection with developing technology in robotics, haptic feedback, and MicroElectroMechanical Systems.

Wireless vital sign telemetry to hand held computers.

Most physicians and other health care providers share/access patient information via hard copy chart records, telephone conversations, or through hospital computer networks. These modalities are cumbersome when physicians are away from the hospital and ground wiring infrastructure is not readily available. In a prior study, we used wireless in-flight telephony and the Internet to transmit vital signs from an airborne Boeing 757 to three remote locations on the ground. However, because all recipient stations relied on an institutional network to receive the information, it was not possible to transfer data to a given location beyond the hospital campus. We now propose an innovative system capable of transmitting telemetry information from any location in the globe to a single portable computer using Wireless Application Protocol (WAP) technology for the Internet. Medical data including blood pressure, pulse, respiratory rate, end tidal CO2, oxygen saturation and EKG tracings were transferred from a G2 (digital cellular) phone linked to a hand held computer to a remote hand held device and were viewed in real time using customized software. Cellular Digital Packet Protocols (CDPD) enabled data transfer speeds up to 19,200 bps. Advances including the Internet and wireless computer technology may revolutionize the way medical information is shared, making it possible for physicians and health allies to directly access patient data from anywhere at any time.

In-flight continuous vital signs telemetry via the Internet.

BACKGROUND: Current methods available to assess a passenger's life threatening medical condition during in-flight emergencies are inadequate. Critical communication channels between the airplane and ground control rely only on voice communication via a two-way radio. The purpose of this study was to test the efficacy of cellular telephone technology via the Internet as a cost-effective way to obtain the "linking" pathway from an aircraft to a ground medical facility by conducting a simulated on line triage. METHODS: On July 31, 1997, we transmitted vital signs from a Boeing 757, flying from Chicago to Los Angeles, simultaneously to: The Saddle Back Memorial, in Laguna Hills, CA; Hospital Santojanni in Buenos Aires, Argentina; and the Medical Department of American Airlines in Dallas/Fort Worth, TX. Three lead EKG, heart rate, BP, arterial oxygen saturation, end tidal CO2, respiratory rate body temperature and real time video images were collected from a passenger and transmitted to each facility from the aircraft via the Internet. Access to the Internet was gained via the cellular phone aboard the aircraft. RESULTS: A total of 20 different simulated scenarios of an medical emergency condition were successfully transmitted, simultaneously, to all health care facilities. All data was received without any corruption with an average delay time of 1 s. CONCLUSIONS: Close monitoring of the patient can lead to a better understanding and assessment of a medical condition, improve in-flight patient care, accelerate the decision making process by making an early diagnosis, and correct a life-threatening condition before the patient arrives at the destination.

Live interactive broadcast of laparoscopic surgery via the Internet.

BACKGROUND: For the first time in the history of communications, we conducted live interactive broadcasts through the Internet (on August 29, and September 3, 1996). METHODS: Successful transmissions were performed from Pontiac, Michigan, to Laguna Hills, California, and Buenos Aires, Argentina, and participants actively interacted in audio and video formats in real time. RESULTS: Video images were transmitted at a rate of 1-2 frame/s and displayed in a 320 x 240 window at the remote sites. The loss of audio packets averaged 17% with a delay of 0.5-2 s. The broadcasting computer station was also able to receive real-time video and sound from the distant computers, allowing complete interaction between both parties over the duration of each transmission session. Average broadcast time was 1. 5 h +/- 30 min, and the cost of each transmission was equal to that of a regular local phone call. CONCLUSIONS: Videoconferencing via the Internet is a viable method for transmitting information in real time allowing surgeons worldwide to work together during surgical procedures.

Videoconferencing as a medical educational tool: first experience in Argentinean public hospital.

Authors present their experience with first medical videoconferencing program developed in a public Argentinean hospital. Both modalities--room and desktop videoconferencing--were used. The program was exclusively used for educational purposes. A total of twelfth videoconferencing were successfully made using all resources. They included surgical procedures, magisterial lessons, grand rounds, etc. The project proved that videoconferencing is a cost-effective medical education tool, even in developing countries.

Quantitative electroencephalography: a method to assess cerebral injury after hypothermic circulatory arrest.

Although hypothermic circulatory arrest and low-flow cardiopulmonary bypass are routinely used for surgical correction of congenital cardiac anomalies, use of long durations of arrest, often required for more complex repairs, raises serious concerns about cerebral safety. Searching for an intraoperative assessment that can reliably predict cerebral injury, we have found an excellent correlation between changes in quantitative electroencephalography intraoperatively and immediately postoperatively after prolonged hypothermic arrest, and neurologic and behavioral evidence of cerebral injury. After epidural placement of four recording electroencephalographic electrodes and baseline neurologic/behavioral and electroencephalographic assessment, 32 puppies were randomly assigned to one of four groups: hypothermic controls in which cooling to 18 degrees C was followed immediately by rewarming, 30 minutes of hypothermic circulatory arrest at 18 degrees C, 90 minutes of arrest at 18 degrees C, and 90 minutes of low-flow cardiopulmonary bypass at 25 ml/kg per minute at 18 degrees C. An electroencephalogram was recorded at baseline, after cooling, during rewarming, and at 2, 4, and 8 hours after the start of rewarming, as well as before the operation and 1 week after the operation. Postoperative neurologic and behavioral outcome was assessed 24 hours after cardiopulmonary bypass and daily for 1 week by means of a graded scale in which 0 is normal and 12 and 13 indicate severe neurologic injury (coma and death). Thirty animals survived the experimental protocol: two animals in the 90-minute hypothermic arrest group died before neurologic evaluation could be completed, and the remainder exhibited various degrees of neurologic and behavioral impairment, more severe on day 1 than on day 6. No animal in the remaining groups had a significant neurologic deficit. Quantitative electroencephalographic analysis shows marked differences between the 90-minute arrest group and the controls in the percent electroencephalographic silence during rewarming and at 2 hours, and in the percent recovery of baseline power at 2, 4, and 8 hours. At 2 hours after the start of rewarming, a correlation between electroencephalographic amplitude and neurologic/behavioral score on day 1 was carried out, which predicts with great certainty (p < 0.00001) that if electroencephalographic power at this time is less than 500 microV2, overt neurologic injury will subsequently become apparent. In addition, a significant shift from higher to lower frequency in the day 6 postoperative electroencephalogram compared with baseline occurs only in the 90-minute arrest group.(ABSTRACT TRUNCATED AT 400 WORDS)

Metabolic correlates of neurologic and behavioral injury after prolonged hypothermic circulatory arrest.

Thirty-two inbred weanling puppies were divided into four groups to study the effect on cerebral blood flow and metabolism of different hypothermic strategies for cerebral protection similar to those used during cardiac operations in infancy. All animals were cooled to 18 degrees C. The animals in the hypothermic control group were immediately rewarmed. One group underwent 30 minutes of hypothermic circulatory arrest at 18 degrees C; another group had 90 minutes of hypothermic circulatory arrest at 18 degrees C, and the final group had low-flow cardiopulmonary bypass (25 ml/kg per minute) at 18 degrees C for 90 minutes. All animals had preoperative and postoperative neurologic and behavioral evaluation and extensive intraoperative monitoring of cerebral blood flow, cerebral vascular resistance, and oxygen and glucose uptake and metabolism: quantitative electroencephalography was also monitored before, during and after operation, but those results are reported separately. Two animals in the 90-minute arrest group died, and all the survivors showed evidence of clinical, neurologic, and behavioral impairment on postoperative day 1, with residual abnormalities in all but one animal on day 6. In contrast, the survivors in all the other groups showed no significant clinical or behavioral sequelae. Cerebral metabolism was reduced only to 32% to 40% of baseline values at 18 degrees C in all groups, although systemic metabolism was only 16% of normal. Cerebral metabolism returned promptly to baseline in all groups during rewarming and remained at baseline levels throughout the 8 hours of follow-up. Cerebral blood flow showed marked hyperemia in the hypothermic arrest groups during rewarming but then significant reductions below baseline values in all groups except the controls at 2 and 4 hours after the operation, lasting as late as 8 hours after the operation in the 90-minute arrest group. Cerebral vascular resistance showed increases in all groups at 2 and 4 hours after the operation, which persisted in the 90-minute arrest group at 8 hours. Cerebral metabolism was maintained at baseline levels despite postoperative decreases in cerebral blood flow and increases in cerebral vascular resistance by increases in oxygen and glucose extraction. The result was very low sagittal sinus oxygen saturations in all groups, most marked in the 90-minute arrest groups, which had a saturation of only 24% 8 hours after the operation. Our data show a severe, prolonged disturbance in cerebral blood flow and cerebral vascular resistance after 90 minutes of hypothermic circulatory arrest at 18 degrees C, which correlates with clinical evidence of cerebral injury.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of retrograde cerebral perfusion to antegrade cerebral perfusion and hypothermic circulatory arrest in a chronic porcine model.

Retrograde cerebral perfusion (RCP) is a new method of cerebral protection that has been touted as an improvement over hypothermic circulatory arrest (HCA). However, RCP has been used clinically for durations and at temperatures that are "safe" for HCA alone. This study was designed to compare RCP to HCA and antegrade cerebral perfusion (ACP) deliberately exceeding "safe" limits, in order to determine unequivocally whether RCP provides better cerebral protection than HCA. Four groups of six Yorkshire pigs (20 to 30 kg) were randomly assigned to undergo 90 minutes of RCP, ACP, HCA, or HCA with heads packed in ice (HCA-HP) at an esophageal temperature of 20 degrees C. Arterial, mixed venous and cerebral venous oxygen, glucose and lactate contents; quantitative EEG; were monitored at baseline (37 degrees C); at the end of cooling cardiopulmonary bypass (20 degrees C); during rewarming (30 degrees C); and at two and four hours post intervention. Animals were recovered and were evaluated daily using a quantitative behavioral score (0 to 9). Mean behavioral score was lower in the HCA group than in the other three groups at seven days (HCA 5.8 +/- 1.1; RCP 8.5 +/- 0.2; ACP 9.0 +/- 0.0; HCA-HP 8.5 +/- 0.2, p < 0.05). Recovery of QEEG was better in the ACP group than in all others, but the RCP group had faster EEG recovery than HCA alone, although not better than HCA-HP (HCA 15 +/- 4; RCP 27 +/- 3; ACP 78 +/- 5; HCA-HP 19 +/- 3, p < 0.001). However, histopathological evidence of ischemic injury was present in 5 of 6 HCA animals and also in 4 of 6 of the HCP-HP group, but only in 1 of 6 RCP animals and in none of the ACP group. This study demonstrates that ACP affords the best cerebral protection by all outcome measures, but RCP provides clear improvement compared to HCA.

Pathogenesis of spinal cord injury during simulated aneurysm repair in a chronic animal model.

The pathogenesis of paraplegia after repair of thoracic aortic aneurysms is controversial. Using direct spinal cord evoked potential monitoring, critical intercostal arteries (CICA) were identified to evaluate the impact of backbleeding and ligation versus that of preservation during simulated aneurysm repair. Thirty pigs (40 kg) were randomly assigned to one of five groups. In groups 1 through 4, a thoracic segment containing CICA was cross-clamped for 60 minutes and distal aortic perfusion was provided by a centrifugal pump. In groups 1 and 2, the thoracic segment was vented, maintaining segment pressure at 0 mm Hg; CICA were ligated in group 1 and preserved in group 2. Thoracic segment was perfused at 70 mm Hg in groups 3 and 4; CICA were ligated in group 3 and preserved in group 4. Critical intercostal artery ligations were performed at the end of the cross-clamp period. In group 5 simple cross-clamping at the left subclavian artery was performed as a control. The combination of venting and ligation of CICA correlated with impaired neurologic outcome according to Tarlov's score (median, 1.5 in group 1 versus 3 in group 2; p = 0.015), indicated by a significant difference in median values of direct spinal cord evoked potential amplitude (expressed as a fraction of baseline values) at 120 minutes after cross-clamping (0.76 in group 1 versus 0.98 in group 2; p = 0.0082).(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of cerebral metabolism and quantitative electroencephalography after hypothermic circulatory arrest and low-flow cardiopulmonary bypass at different temperatures.

Although widely used for repair of complex cardiovascular pathologic conditions, long intervals of hypothermic circulatory arrest and low flow cardiopulmonary bypass may both result in cerebral injury. This study examines cerebral hemodynamics, metabolism, and electrical activity to evaluate the risks of cerebral injury after 60 minutes of hypothermic circulatory arrest at 8 degrees C, 13 degrees C, and 18 degrees C, compared with 60 minutes of low flow cardiopulmonary bypass at 18 degrees C. Thirty-two puppies were randomly assigned to one of four experimental groups and centrally cooled to the appropriate temperature. Serial evaluations of quantitative electroencephalography, radioactive microsphere determinations of cerebral blood flow, calculations of cerebral oxygen consumption, cerebral glucose consumption, cerebral vascular resistance, cerebral oxygen extraction, systemic oxygen metabolism, and systemic vascular resistance were done. Measurements were obtained at baseline (37 degrees C), at the end of cooling, at 30 degrees C during rewarming, and at 2, 4, and 8 hours after hypothermic circulatory arrest or low flow cardiopulmonary bypass. At the end of cooling, cerebral vascular resistance remained at baseline levels in all groups, but systemic vascular resistance was increased in all groups. Cerebral oxygen consumption became progressively lower as temperature was reduced: it was only 5% of baseline at 8 degrees C; 20% at 13 degrees C; and 34% and 39% at 18 degrees C. Quantitative electroencephalography was silent in the 8 degrees C and 13 degrees C groups, but significant slow wave activity was present at 18 degrees C. Systemic vascular resistance and cerebral oxygen consumption returned to baseline values in all groups by 2 hours after hypothermic circulatory arrest or low flow cardiopulmonary bypass, but cerebral vascular resistance remained elevated at 2 and 4 hours, not returning to baseline until 8 hours after hypothermic circulatory arrest or low flow cardiopulmonary bypass. All but two of the long-term survivors (27 of 32) appeared neurologically normal; after hypothermic circulatory arrest at 8 degrees and 18 degrees C two animals had an unsteady gait. Comparison of quantitative electroencephalography before operation and 6 days after operation showed a significant increase in slow wave activity (delta activity) after hypothermic circulatory arrest and low flow cardiopulmonary bypass at 18 degrees C, a change that suggests possible cerebral injury. Although undetected after operation by simple behavioral and neurologic assessment, significant differences in cerebral metabolism, vasomotor responses, and quantitative electroencephalography do exist during and after hypothermic circulatory arrest and low flow cardiopulmonary bypass at various temperatures and may be implicated in the occurrence of cerebral injury.(ABSTRACT TRUNCATED AT 400 WORDS)