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Results for “Intraoperative Awareness”

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PubMed1995

Awareness detection during caesarean section under general anaesthesia using EEG spectrum analysis.

This study examined the relationship between the EEG (spectral edge frequency 90-SEF90) and the occurrence of awareness defined for the purpose of this study as responsiveness to verbal commands. Fifty women undergoing general anaesthesia for elective Caesarean section were examined. Responsiveness to verbal commands was detected every minute in the period from the induction of anaesthesia to the delivery of the newborn using the Tunstall isolated forearm technique and correlated with the SEF90 value. The patients were assigned by a randomized code to receive either thiopentone (4 mg.kg-1) or ketamine (1 mg.kg-1) for induction of anaesthesia. Before the administration of succinylcholine a tourniquet was applied to the free arm, and inflated to 200 mmHg, to maintain motor function to one arm. The EEG recordings started five minutes before induction and were recorded throughout anaesthesia. The incidence of responsiveness to verbal commands was lower in the ketamine group (24%) where the average SEF90 was 12.0 +/- 3 Hz, than in the thiopentone group (52%), where the average SEF90 was 18.09 +/- 3 Hz (P = 0.01). The results suggest that SEF values of < or = 8.6 Hz were sufficient to avoid responsiveness to verbal commands.

Adult↗

PubMed2004

Entropy during propofol hypnosis, including an episode of wakefulness.

Depth of anaesthesia has proved to be a complex process to quantify. Monitors based on bispectral analysis of the electroencephalogram and auditory evoked potential have been available, but only recently has a monitor based on entropy become available. This study determined state entropy and response entropy in nine healthy volunteers during propofol hypnosis with a brief intervening period of wakefulness. Both the calculated entropy indices decreased with increasing levels of sedation (r2 = 0.58 and 0.61, respectively) and they showed a high correlation with each other (r2 = 0.94). However, an overlap was observed in real time indices between different stages of the Observer's Assessment of Alertness/Sedation Scale. Only three of the nine volunteers had explicit memories from the episode of wakefulness. Electroencephalographic entropy monitors seem to have potential for staging clinical hypnotic effects.

Adolescent↗

PubMed1987

Post-tonsillectomy bleeding: an evaluation of risk factors.

While tonsillectomy is usually a safe operation, it is always accompanied by the risk of immediate postoperative bleeding. Despite continued efforts to eliminate this problem, it remains a persistent risk. In reviewing 775 consecutive cases of tonsillectomy, immediate postoperative bleeding occurred in 21 (2.7%). Diagnostic, demographic, hematologic, hemodynamic and surgical management factors were evaluated. The role of local anesthesia for tonsillectomy was also examined. Postoperative bleeders were more likely to have abnormal preoperative clotting studies, greater elevations of their mean postoperative blood pressures, and unusual surgical indications. Local anesthetic cases were shorter, had less intraoperative bleeding and were not associated with greater postoperative bleeding. We conclude that local anesthesia is safe and efficient and that identifiable factors are associated with primary post-tonsillectomy bleeding. An awareness of these factors can help identify potential postoperative bleeders.

Adolescent↗

PubMed2006

Cricoid cartilage on sonography in pediatric patients mimics a thyroid mass.

OBJECTIVE: The purpose of this study was to describe the sonographic appearance of the uncalcified cricoid cartilage in pediatric patients and illustrate how this can be easily confused with a thyroid mass or residual thyroid tissue after thyroidectomy. METHODS: We retrospectively reviewed the sonographic and computed tomographic examinations performed on 4 adolescent patients. Two patients had either thyroid cancer or thyroid nodules, and 2 healthy patients were reviewed to show normal anatomy. Results were compared with the clinical and surgical findings in each patient. RESULTS: Computed tomographic and sonographic examinations showed the normal anatomic relationships and imaging appearance of the cricoid cartilage. Findings from a follow-up sonographic examination on a patient with treated thyroid cancer were initially interpreted as residual thyroid tissue, but another examination revealed that this tissue was actually uncalcified cricoid cartilage. Another patient who had intraoperative sonography verified these findings. CONCLUSIONS: Uncalcified cricoid cartilage in a pediatric patient appears on sagittal sonography as a round or ovoid structure with variable echogenicity, located posteromedial to the thyroid gland. Awareness of this structure's sonographic appearance should prevent unnecessary biopsy or surgery.

Adolescent↗

PubMed2001

An anaphylactic reaction possibly associated with an intraoperative coronary artery spasm during general anesthesia.

We report a case of anaphylactic reaction occurring during general anesthesia that may have been accompanied by a coronary artery spasm. The present case and a review of the medical literature suggest that coronary artery spasm is evoked by common vasoactive mediators with anaphylactic reactions. Coronary artery spasm should be counted as a symptom of the cardiovascular manifestation of anaphylaxis. Clinicians should be aware of this possible complication when treating an anaphylactic reaction, especially in patients at risk for atherosclerosis. Early recognition of ST segment elevation is essential for diagnosis and treatment of coronary artery spasm.

Aged↗

PubMed1990

Risk of exposure of surgical personnel to patients' blood during surgery at San Francisco General Hospital.

We undertook an observational study of 1307 consecutive surgical procedures at San Francisco General Hospital to record descriptions of intraoperative exposures to blood and other body fluids, determine the factors predictive of these exposures, and identify interventions that might reduce their frequency. During a two-month period, circulating nurses took note of parenteral and cutaneous exposures to blood and recorded information about all procedures. In a follow-up validation study, 50 additional procedures were observed by the study investigators to determine the accuracy of the data collected by the nurses. A total of 960 gloves used by surgical personnel during the validation study were examined to determine the perforation rate. Accidental exposure to blood (parenteral or cutaneous) occurred during 84 procedures (6.4 percent; 95 percent confidence interval, 5.1 to 7.8 percent). Parenteral exposure occurred in 1.7 percent. The risk of exposure was highest when the procedures lasted more than three hours, when blood loss exceeded 300 ml, and when major vascular and intraabdominal gynecologic surgery was involved. Neither knowledge of diagnosed human immunodeficiency virus (HIV) infection nor awareness of a patient's high-risk status for such infection influenced the rate of exposure. Double gloving prevented perforations of the inner glove and cutaneous exposures of the hand. We conclude that all surgical personnel are at risk for intraoperative exposure to blood. Our data support the practice of double gloving and the increased use of water-proof garments and face shields to prevent mucocutaneous exposures to blood. No evidence was found to suggest that preoperative testing for HIV infection would reduce the frequency of accidental exposures to blood.

Accidents, Occupational↗

PubMed2003

Relationship between awareness and middle latency auditory evoked responses during surgical anaesthesia.

BACKGROUND: Some studies support the view that meaningful auditory input can be processed by the brain during apparent surgical anaesthesia. Consequently, patients may be able to remember some information implicitly after anaesthesia as well through a 'dream-like process' (subconscious awareness). The aim of this study was to investigate the presence of subconscious awareness during anaesthesia and to examine its relationship to the mid-latency auditory evoked responses (MLAERs). METHODS: We studied 40 patients, ASA I-II, undergoing laparoscopic cholecystectomy. General anaesthesia was induced with thiopental 5 mg kg(-1), fentanyl 3 micro g kg(-1), and vecuronium 0.08 mg kg(-1). For the maintenance of anaesthesia, patients were randomly assigned to one of four anaesthetic regimen groups: sevoflurane+air in oxygen 40%; sevoflurane+nitrous oxide 60%; isoflurane+air in oxygen 40%; and isoflurane+nitrous oxide 60%. MLAERs were recorded before anaesthesia, at 1 MAC of inhaled anaesthetic and then 30 min after awakening. An audiotape with one of four stories was played immediately after intraoperative MLAER recording. Explicit and implicit memory was assessed 24 h after awakening. RESULTS: None of the patients had explicit recall. One of the patients from the isoflurane-air group showed implicit memory of listening to the audiotape. A dream-like process, in which they remembered implicitly the story played during anaesthesia, occurred in one of the patients from the sevoflurane-nitrous oxide group. In the patients with subconscious awareness, MLAERs were similar to that of the awake state with a Pa latency increase of less than 8.87. When there was a marked increase in Pa latency during anaesthesia, no subconscious awareness was observed. No statistically significant differences were found between Pa latency before and after anaesthesia. CONCLUSIONS: MLAERs may help to predict subconscious cerebral processing of auditory inputs during anaesthesia.

Adolescent↗

PubMed1988

Rigid ureteroscopy: pitfalls and remedies.

One hundred fifty patients underwent rigid ureteroscopy for stone extraction. With adequate experience and awareness of the potential pitfalls and possible remedies, success rates of over 90 per cent can be achieved.

Endoscopy↗

PubMed2000

Ureteral displacement associated with pelvic peritoneal defects and endometriosis.

Ten women had endometriosis and pelvic peritoneal defects of the posterior leaf of the broad ligament, with the consistent finding of medial displacement of the ureter toward the uterosacral ligament. Ureterolysis at the time of surgery revealed the underlying course of the ureter and its proximity to the uterosacral ligament, making it susceptible to surgical injury. It is important for surgeons to be aware of this anatomic alteration associated with these specific peritoneal defects.

Broad Ligament↗

PubMed2006

Complications of cemented long-stem hip arthroplasties in metastatic bone disease.

UNLABELLED: It is controversial whether a cemented long-stem femoral arthroplasty is a safe surgical option for patients with meta-static bone disease of the hip. Cemented long stems increase the risk of embolic cascades and may cause subsequent cardiopulmonary complications, particularly in patients with metastatic disease. We retrospectively reviewed results of 29 long-stem cemented femoral arthroplasties in 27 patients in which surgical techniques that minimized intramedullary debris and canal pressurization were used. The surgical techniques minimized intraoperative cement-related emboli with aggressive medullary lavage, intraoperative canal suctioning during cementation, use of early low-viscosity polymethylmethacrylate, and slow, controlled insertion of the long-stem prosthesis. Cement-associated hypotension occurred in four (14%) patients, sympathomimetics were administered in nine (31%) patients, and a worsening mental status occurred postoperatively in one (3%) patient. There were no cement-associated desaturation events, cardiac arrests, or intraoperative deaths. No patients required prolonged intubation, and there were no postoperative cardiopulmonary events. Cemented long-stem femoral arthroplasty is a safe procedure for patients with high-risk metastatic disease. Increased awareness of cement-related cardiopulmonary pathophysiology, and modifying conventional surgical techniques can minimize cement-associated complications. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Adult↗

PubMed2004

[Bispectral analysis of the electroencephalogram: a new method for recording the level of consciousness during anaesthesia].

Until recently, no measure was available that provided objective and reproducible information on the level of consciousness in patients under general anaesthesia. Several decades of research to find a reliable measure for determining the depth of anaesthesia has now led to the clinical introduction of the bispectral index scale (BIS), a parameter derived from the electroencephalogram. Implementation of the BIS-monitor in anaesthetic practice leads to a reduced use of hypnotic agents, a more rapid recovery phase and possibly a reduced incidence of awareness.

Anesthesia Recovery Period↗

PubMed1987

[Coagulopathy and anemia caused by anticonvulsants].

Long-term antiepileptic polytherapy regularly induces some slight impairment of haemostasis without clinical manifestations, but serious clinical disorders may appear, even in the absence of over-dosage. In the case reported here the patient was undergoing surgery for correction of scoliosis. Preoperative laboratory tests only showed a slight decrease of fibrinogen and a moderate lengthening of thrombin time; there was no anaemia. Immediately after the incision a severe haemorrhagic syndrome occurred. It was treated with a massive transfusion and administration of some blood coagulation factors, but bleeding was so profuse that surgery was abandoned. Later, the patient developed acute thrombocytopenia, progressive decrease of Quick time and of plasma blood coagulation factors, and anaemia due to folate deficiency. Awareness of these disorders should lead to prophylactic measures.

Adolescent↗

PubMed1997

[Drug-induced laryngospasm].

We report a case of drug-induced laryngospasm due to Chlorpromazine. A drug-induced laryngospasm has not been previously reported in the literature. A 70-year-old male with the proximal end fracture of the femur was scheduled for the operative fixation. He had a past history of alcoholism and had underwent a long-term chlorpromazine therapy for 45 years until admission to our hospital. There have been a few reports on unexplained sudden deaths of patients receiving long-term treatment with chlorpromazine. Caution was therefore needed in general anesthesia, which was thought to be safer than epidural or spinal anesthesia in this case. Accordingly for the preparation of an emergency operation, the central venous catheterization via the internal jugular vein was performed under subcutaneous injection of lidocaine. Severe dyspnea and cyanosis occurred a few minutes after the administration of lidocaine. The specific diagnosis of laryngospasm was made by inspection of the vocal cords. Immediate oral intubation was performed and no complications ensued during and after the operation. This episode strongly suggests that one reason of the unexplained sudden deaths of patients receiving long term treatment with chlorpromazine could be laryngospasm. In conclusion, anesthesiologists should be aware of the possibility of laryngospasm under similar conditions.

Aged↗

PubMed1992

Dissociation of somatosensory and motor evoked potentials in a patient with an intramedullary spinal tumor.

We describe a patient with an intramedullary spinal tumor who demonstrated postoperative improvement of motor and sensory function despite the lack of somatosensory evoked potentials (SSEPs) before and after intraoperative monitoring. The motor system was evaluated by direct spinal cord stimulation across the tumor bed. The resultant evoked compound muscle action potentials and compound nerve activities were normal. Although there is sufficient clinical evidence that SSEPs are sensitive to posterior and posterolateral ischemic insults of the spinal cord, the technique should be employed with an awareness of its limitations in monitoring the descending tracts which have a different blood supply and occupy more anterior locations in the spinal cord.

Arm↗

PubMed2004

[Phacoemulsification cataract surgery in vitrectomized eyes].

OBJECTIVE: This study focuses on determining the intra- and post-operative complications stemming from technical difficulties, anatomical aspects, intraoperatory management and visual outcome of post-vitrectomized patients that undergo phacoemulsification. METHOD: In this prospective, longitudinal, observational and descriptive study phacoemulsification was performed in 25 post-vitrectomized eyes that required cataract surgery. Pre-surgical variables: sex, age, affected eye, visual accuity, underlying vitreoretinal disease, anterior segment morphological findings such as: cataract density and pupil alterations. Intrasurgical variables: characteristic of anterior chamber and pupil, phacoemulsification technique and time and the presence of complications. Post-surgical variables were also registered: visual capacity and the presence of complications. Minimum six-month follow-up period. RESULTS: The average interval between pars plana vitrectomy and phacoemulsification was 18.5 months. Silicone oil was the most frequent tamponade used in our serie (44%). Biomicroscopical findings were miosis 28% and posterior synechies 24%. The average interval of phaco time was 2.26 minutes. The intraoperative findings were fluctuations in the anterior chamber depth (24%) and anterior capsular tears (12%). The postoperative complications most frequently seen were posterior capsular plaque (28%) and corneal edema (16%). CONCLUSIONS: Phacoemulsification is a safe and effective technique in eyes after pars plana vitrectomy that require cataract surgery. The surgeon must be aware of the morphological and anatomical findings of these eyes. Visual rehabilitation will generally be determined by the presence of an underlying vitreo-retinal pathology.

Adolescent↗

PubMed1989

The oculocardiac reflex in blepharoplasty surgery.

The oculocardiac reflex (OCR), a previously undescribed phenomenon in aesthetic blepharoplasty surgery, involves intraoperative bradycardia exceeding 10 percent of the preoperative heart rate or any dysrhythmia during ocular manipulation. It is a trigeminal-vagal-mediated reflex arc. The oculocardiac reflex was noted to occur in 25 of 100 patients (25 percent) undergoing blepharoplasty. A data sheet designed and distributed for use in the operating room identified a reflex-prone patient (RPP) as a young, anxious female, with a cardiac history, operated on under light anesthesia with aggressive fat pad resection. The oculocardiac reflex was more likely to occur in a reflex-prone patient during traction on the medial fat pads and in the left eye. Despite anticipating the fatigue phenomenon in those patients who exhibited a profound bradycardia (35 to 40 beats per minute), it was necessary to release traction in order to permit the heart rate to return to normal. Awareness and treatment of this potentially life-threatening oculocardiac reflex are necessary. Careful patient surveillance and monitoring are mandatory.

Adult↗

PubMedDate not supplied

Antiplatelet agents in the perioperative period: expert recommendations of the French Society of Anesthesiology and Intensive Care (SFAR) 2001--summary statement.

PURPOSE: Antiplatelet agents are administered to an increasing number of patients. Preoperative treatment with these agents represents a major problem for the anesthesiologist. The results of a French expert meeting on their perioperative management are reported. METHODS: Responses to questions formulated by the Organizing Committee were drafted by a group of experts and reviewed by a multidisciplinary. Reading Committee. Recommendations were classified (grade) according to the evidence level of the studies supporting them. PRINCIPAL FINDINGS: First, antiplatelet agents have a variable effect on hemostasis as far as bleeding risk is concerned. Aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) increase intra- and postoperative bleeding moderately, but not transfusion requirements. Very few data are available on clopidogrel and ticlopidin. Anti-glycoprotein (GP) IIb/IIIa agents may increase bleeding when surgery is required in proximity with their administration. Second, the common practice of withdrawing antiplatelet agents is now challenged because an increased incidence of myocardial infarction has been reported in patients in whom treatment was interrupted. Third, aspirin should not be withdrawn for most vascular procedures and in several additional settings. When a definite increase in intraoperative bleeding is feared, or when surgical hemostasis is difficult, aspirin, clopidogrel or ticlopidine can be replaced by short-acting NSAIDS, given for a ten-day period and interrupted the day before surgery. Platelet transfusion should only be given when overt bleeding is observed. Postoperatively, antiplatelet treatment should be resumed immediately after surgery (first six hours). CONCLUSION: Anesthesiologists should be aware of the indications, potential complications and means of substitution of these agents.

Anesthesia↗

PubMed2004

Accuracy of surgeon-performed ultrasound in parathyroid localization.

Ultrasound is one of the preferred modalities for localization of abnormal parathyroids. Accuracy of ultrasound is technician-dependent. This study was undertaken to determine the accuracy of surgeon-performed ultrasound (SPU) for the localization of parathyroid tumors in comparison to radiology-performed ultrasound (RPU) and nuclear scintigraphy (NS). In this series 74 consecutive patients with untreated primary hyperparathyroidism underwent SPU at the initial clinic visit; 21 of these patients did not undergo surgery and are excluded from the analysis. Of the 53 patients remaining, RPU was obtained in 26, and 52 patients underwent NS. Directed parathyroidectomy was performed with use of the intraoperative parathyroid hormone assay (IOPTH). In all, 46 patients had a single adenoma as indicated by IOPTH and final pathology. Two patients had double gland disease, and 5 patients had multi-gland hyperplasia. The sensitivity of SPU was 82% and the specificity was 90% in detecting the diseased glands on the correct side (right versus left). The sensitivity for RPU was 42% and the specificity was 92% (n = 26). The sensitivity of NS was 44% and the specificity was 98% (n = 52). In only one case did RPU or NS detect a gland not found by SPU. SPU can be done with accuracy comparable to other ultrasound series in the literature, and it may be superior to RPU or NS in some institutions. It is important for surgeons to be aware of local institutional expertise when relying on RPU and NS during preoperative evaluation prior to directed parathyroidectomy.

Adenoma↗