Dietrich Gravenstein

Transurethral Resection of the Prostate (turp) Syndrome: A Review of the Pathophysiology and Management

W henever irrigation fluid enters the intravascular space, dangerous complications can arise. This is best described as the transurethral resection of the prostate (TURF’) syndrome. The syndrome has also been reported after endometrial ablation (l-5) and ureteroscopic procedures with irrigating solutions (6-8). TURF’ syndrome may occur as quickly as 15 minutes after resection starts (9-ll), or up to 24 hours postoperatively (12). Of approximately 400,000 TURP procedures each year (13), 10% to 15% incur TURP syndrome (14,15) and the mortality is 0.2% to 0.8% (16,17). TURP syndrome affects many systems and manifests itself mainly through acute changes in intravascular volume and plasma solute concentrations (Figure 1). Despite this seemingly consistent etiology, TURP syndrome lacks a stereotypical presentation; therefore, its diagnosis is difficult (Table 1) (14,18-23). Further, recent work suggests that the conventional perioperative management of both TURP and the TURP syndrome may have to be revised.

An integrated graphic data display improves detection and identification of critical events during anesthesia.

Objective. To show that an integrated graphic data display can shorten thetime taken to detect and correctly identify critical events during anesthesia.Methods. We developed a graphic display which presents 30 anesthesia-relatedphysiologic variables as shapes and colors, rather than traditional digits andwaveforms. To evaluate the new display, we produced four critical events ona computer-based anesthesia simulator and asked two groups of fiveanesthesiologists to identify the events as quickly as possible. One groupobserved the new display while the other group viewed a traditionalcardiovascular monitor with digital and waveform displays. Results. The groupwhich observed the integrated graphic display saw changes caused by inadequateparalysis 2.4 min sooner, and changes caused by a cuff leak 3.1 min soonerthan those observing the traditional display. The integrated display groupcorrectly identified the reason for the change 2.8 min sooner for inadequateparalysis, 3.1 min sooner for cuff leak and 3.1 min sooner for bleeding. Thesedifferences were all statistically significant. Conclusions. The results showthat some simulated critical events are detected and correctly identifiedsooner, when an anesthesiologist views an integrated graphic display, ratherthan a traditional digital/waveform monitor.

Supplemental Oxygen Compromises the Use of Pulse Oximetry for Detection of Apnea and Hypoventilation During Sedation in Simulated Pediatric Patients

OBJECTIVE. The goal was to assess the time to recognition of apnea in a simulated pediatric sedation scenario, with and without supplemental oxygen. METHODS. A pediatric human patient simulator mannequin was used to simulate apnea in a 6-year-old patient who received sedation for resetting of a fractured leg. Thirty pediatricians participating in a credentialing course for sedation were randomly assigned to 2 groups. Those in group 1 (N = 15) used supplemental oxygen, and those in group 2 (N = 15) did not use supplemental oxygen. A third group (N = 10), consisting of anesthesiology residents (postgraduate years 2 and 3 equivalent), performed the scenario with oxygen supplementation, to ensure validity and reliability of the simulation. The time interval from simulated apnea to bag-mask ventilation was recorded. Oxygen saturation and Paco2 values were recorded. All recorded variables and measurements were compared between the groups. RESULTS. The time interval for bag-mask ventilation to occur in group 1 (oxygen supplementation) was significantly longer than that in group 2 (without oxygen supplementation) (173 ± 130 and 83 ± 42 seconds, respectively). The time interval for bag-mask ventilation to occur was shorter in group 3 (anesthesiology residents) (24 ± 6 seconds). Paco2 reached a higher level in group 1 (75 ± 26 mmHg), compared with groups 2 and 3 (48 ± 10 and 42 ± 3 mmHg, respectively). There was no significant difference between the groups in oxygen saturation values at the time of clinical detection of apnea (93 ± 5%, 88 ± 5%, and 94 ± 7%, respectively). CONCLUSIONS. Hypoventilation and apnea are detected more quickly when patients undergoing sedation breathe only air. Supplemental oxygen not only does not prevent oxygen desaturation but also delays the recognition of apnea.

Clinical assessment of a plastic optical fiber stylet for human tracheal intubation

BACKGROUND The authors compared the performance of a prototype intubation aid that incorporated plastic illumination and image guides into a stylet with fiberoptic bronchoscopy and direct laryngoscopy for tracheal intubation by novice users. METHODS In a randomized, nonblinded design, patients were assigned to direct laryngoscopy, fiberoptic bronchoscopy, or imaging stylet intubation groups. The quality of laryngeal view and ease with which it was attained for each intubation was graded by the laryngoscopist. Time to intubation was measured in 1-min increments. A sore-throat severity grade was obtained after operation. RESULTS There were no differences in demographic, physical examination, or surgical course characteristics among the groups. The laryngoscope produced an adequate laryngeal view more easily than did the imaging stylet or bronchoscope (P = 0.001) but caused the highest incidence of postoperative sore throat (P<0.05). Although the time to intubation for direct laryngoscopy was shorter than for imaging stylet, which was shorter than fiberoptic bronchoscopy (P<0.05), the quality of laryngeal view with the imaging stylet was inferior to both direct laryngoscopy and fiberoptic bronchoscopy techniques (P<0.05). CONCLUSIONS Novices using the imaging stylet produce fewer cases of sore throat (compared with direct laryngoscopy) and can intubate faster than when using a bronchoscope in anesthetized adult patients. The imaging stylet may be a useful aid for tracheal intubation, especially for those unable to maintain skills with a bronchoscope.

Somatosensory evoked potentials in hysterical paraplegia

Somatosensory evoked potentials were determined in three patients with hysterical neurologic deficits after minor trauma. In each case the patient denied any sensation of the stimulus in the affected extremity; however, normal evoked potentials were recorded. Objective evidence of the hysterical nature of the neurologic deficit was, therefore, provided.

Subdural air collection: a likely source of radicular pain after lumbar epidural.

This case conference reports two cases of epidural anesthesia in which air was used to identify the epidural space during a loss-of-resistance placement technique. Both patients subsequently complained of severe pain and subdural air was demonstrated in case 1 by computed tomography and in case 2 by magnetic resonance imaging. The possible causes of the pain syndrome experienced by both patients are discussed.

The Stealth Station Image Guidance System may interfere with pulse oximetry.

PurposeInterference on pulse oximetry can come from many sources. We found an additional source of interference from the Stealth Station. This article gives an overview of sources of pulse oximeter interference so that clinicians can better prevent them.Technical featuresThis article discusses the infrared disturbances caused by the Stealth Station. The Stealth Station is a frameless stereotactic positioning system that utilizes a three dimensional location system to measure the position of the patient and the surgical tools, and to relate those positions to previously recorded imaging. To understand the disturbance caused by the Stealth Station, we discuss its operation and that of pulse oximeter monitors. Pulse oximeter interference can come from volume artifacts, electrical and light noise, and can be caused by issues related to the patient. Because the passive Stealth Station contains a strong infrared light source, interference caused by light is a likely reason for the interference we noted. Pulse oximeters rely on the timevariant light signal modulated by arterial volume variations in the finger. Although relatively immune to static light sources, pulse oximeters are extremely sensitive to time-varying light sources. The light emitted by the passive Stealth Station is time-varying at 4 Hz and this is causing the pulse oximeter to provide invalid results. Shielding can generally be used to stop the light from the Stealth Station from being picked up by the pulse oximeter sensor.ConclusionInfrared light interference can be very common, but is easily dealt with if one is aware of it.ObjectifL’interférence sur la sphygmo-oxymétrie peut provenir de nombreuses sources, dont une nouvelle provenant de la Stealth Station. Nous présentons un aperçu des interférences avec le sphygmo-oxymètre, ce qui permettra aux cliniciens de la prévenir.Caractéristiques techniquesLa Stealth Station est un système de positionnement stéréotaxique sans cadre qui utilise un système de repérage en trois dimensions pour mesurer la position réelle du patient et des instruments chirurgicaux et pour relier cette position à des images virtuelles préalablement enregistrées.L’interférence avec le sphygmo-oxymètre peut provenir d’artéfacts volumique, des produits électriques et de légers bruits et elle peut être causée par des problèmes reliés au patient. Comme la Stealth Station passive contient une puissante source de lumière à infrarouges, c’est une raison probable de l’interférence notée. Les sphygmo-oxymètres dépendent du signal lumineux variable dans le temps qui est modulé par les variations du volume artériel dans le doigt. Bien que relativement soustraits aux sources de lumière statiques, les sphygmo-oxymètres sont extrêmement sensibles aux sources de lumière variables dans le temps. La lumière émise par la Stealth Station passive varie dans le temps à 4 Hz, ce qui invalide certains résultats au sphygmooxymètre. Une protection peut généralement être utilisée pour empêcher la lumière provenant de la Stealth Station d’être captée par le détecteur du sphygmo-oxymètre.ConclusionL’interférence de la lumière infrarouge peut se rencontrer souvent, mais on peut facilement la contourner pourvu qu’on en prenne conscience.

Autoregulation in a Simulator-Based Educational Model of Intracranial Physiology

Objective.To implement a realistic autoregulation mechanism toenhance an existing educational brain model that displays in real-time thecerebral metabolic rate (CMRO2), cerebral blood flow (CBF),cerebral blood volume (CBV), intracranial pressure (ICP), and cerebralperfusion pressure (CPP). Methods.A dynamic cerebrovascular resistance(CVR) feedback loop adjusts automatically to maintain CBF within a range ofthe CPP and defines autoregulation. The model obtains physiologic parametersfrom a full-scale patient simulator. We assumed that oxygen demand andarterial partial pressure of carbon dioxide (CO2 responsivity) arethe two major factors involved in determining CBF. In addition, our brainmodel increases oxygen extraction up to 70% once CBF becomes insufficient tosupport CMRO2. The model was validated against data from theliterature. Results.The models response varied less than 9%from the literature data. Similarly, based on correlation coefficients betweenthe brain model and experimental data, a good fit was obtained for curvesdescribing the relationship between CBF and PaCO2 at a meanarterial blood pressure of 150 mm Hg (R2 = 0.92) and 100 mm Hg(R2 = 0.70). Discussion.The autoregulated brain model, withincorporated CO2 responsivity and a variable oxygen extraction,automatically produces changes in CVR, CBF, CBV, and ICP consistent withliterature reports, when run concurrently with a METI full-scale patientsimulator (Medical Education Technologies, Inc., Sarasota, Florida). Once themodel is enhanced to include herniation, vasospasm, and drug effects, itsutility will be expanded beyond demonstrating only basic neuroanesthesiaconcepts.

Airway management of patient with Smith–Lemli–Opitz syndrome for gastric surgery: case report

A case of term, 5‐day‐old boy, with low birth weight of 2.4 kg, with Smith–Lemli–Opitz syndrome (SLOS) who was first scheduled for gastrostomy tube placement and later for pylorotomy, is discussed. General appearance of face and small chin showed possible difficulties during intubation, which are well known from the literature. Anesthetic plan included possibility of fiberoptic intubation. Mask induction and ventilation had been successful but attempts to intubate patient using fiberoptic bronchoscope had not been feasible and both procedures had been performed using laryngeal mask airway (LMA#1) with spontaneous ventilation without complications. In this case, we are showing the ability to secure the airway in a small infant with SLOS using LMA and the possibility to perform successfully surgery on the gastrointestinal tract.

Fractured Small Gauge Needle During Attempted Combined Spinal-Epidural Anesthesia for Cesarean Delivery

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