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At least 289 records · Page 16Linked to original sources
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↗
PubMedDate not supplied

Effect of intraocular irrigating solution on flicker electroretinogram during cataract surgery in human eye.

The effects of two commercially available intraocular irrigating solutions, Opeguard MA and BSS Plus, were studied during extracapsular cataract surgery in 45 eyes of 35 patients. After irrigation and aspiration of the residual cortex with Opeguard MA or BSS-Plus, the ERG amplitude increased, respectively, to 111.2+/-5.8% and 109.5+/-5.3% of the preirrigation amplitudes. The increases reached significance (116.9+/-7.0% and 115.7+/-6.5%; both P < .05) at the end of surgery compared with pre-irrigation ERG amplitudes. After irrigation with Opeguard MA or BSS-Plus, the ERG peak times were significantly prolonged to 103.9+/-0.8% and 104.2+/-1.2%, respectively, of the preirrigation peak times (both P < .01). The ERG peak times significantly shortened to 101.5+/-0.9% and 101.3+/-1.22%, respectively, at the end of surgery (P < .001 and P < .05) compared with just after irrigation. Although we have previously shown that Opeguard MA maintained amplitude and implicit time of 30 Hz flicker ERG during vitrectomy better than BSS-Plus, there were no statistically significant differences between the changes in amplitude and peak time with Opeguard MA and BSS-Plus during cataract surgery. We speculate that a drop in the retinal temperature during irrigation and aspiration in the anterior chamber and an increase in the photopic ERG amplitude during light adaptation with the operating microscope caused these ERG changes.

Aged↗
PubMed2003

Noxious stimulation during orthopaedic surgery results in EEG 'arousal' or 'paradoxical arousal' reaction in isoflurane-anaesthetised sheep.

The effects of surgical stimuli on haemodynamic and electroencephalographic (EEG) variables were determined in 25 adult ewes undergoing an experimental orthopaedic procedure in isoflurane anaesthesia. Data were recorded after 15 min of constant end-tidal concentration of approximately 2.2% isoflurane (SS: steady state=baseline), during skin disinfection (DIS), incision (INC), drilling of the first hole through the tibia (DRI) and insertion of a threaded pin (PIN) for external fixation. Stimulation resulted in a significant increase in systolic and mean arterial pressure above SS at INC, DRI and PIN. Haemodynamic changes were accompanied by either significant increases or decreases in EEG median frequency (MF) and 80% spectral edge frequency (SEF80) above or below SS at all four stimulation time points suggesting 'arousal' or 'paradoxical arousal' reaction, respectively. We conclude, that either type of EEG activation pattern could be elicited dependent on stimulation intensity and level of anaesthetic depth.

Anesthesia, General↗
PubMed1992

Electrocardiographic R-wave changes during cardiac surgery.

The diagnostic accuracy of exercise electrocardiography has been improved by incorporation of R-wave gain factor to correct the measured ST-segment changes. If marked changes in R-wave amplitude occur in individual patients during cardiac operations, a similar gain factor correction may improve the intraoperative diagnosis of myocardial ischemia. This investigation was designed to determine the frequency and magnitude of intraoperative V5 R-wave amplitude changes during cardiac operations. Electrocardiograms were recorded from 83 patients while patients were awake, anesthetized (baseline), after placement of the Favaloro and Canadian sternal retractors, and at end-operation. Compared with baseline values, placement of the Canadian sternal retractor was associated with a reduction in V5 R-wave amplitude from 15 +/- 1 to 10 +/- 1 mm (mean +/- SEM), in V5 S-wave amplitude from 3.5 +/- 0.4 to 1.7 +/- 0.3 mm, and in absolute ST-segment deviation from 0.50 +/- 0.04 to 0.39 +/- 0.05 mm. Changes in V5 R-wave amplitude were correlated with changes in ST-segment deviation in patients with baseline ST-segment deviations greater than or equal to 0.5 mm (r = 0.55, P = 0.0004, n = 37). Changes associated with the Favaloro retractor and the respiratory cycle were less marked. However, the V5 R-wave amplitude was decreased from 15 +/- 1 to 9 +/- 1 mm at end-operation. In conclusion, sternal spreading with the Canadian retractor was associated with marked reductions in V5 R- and S-wave amplitudes and ST-segment deviations. Marked changes in V5 R-wave amplitude persisted after sternal closure.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed2006

A comparison of intra- versus post-operatively acquired electrically evoked compound action potentials.

The objective of this study was to compare the electrically evoked compound action potentials, intra- versus post-operatively, in cochlear implant patients. In a prospective study twenty-five consecutively implanted adult patients received a multichannel cochlear implant. In all patients, electrically evoked compound action potentials were recorded immediately after cochlear implantation and in a post-operative setting nine months later. The threshold of the electrically evoked compound action potential was determined in both settings. A high success rate (97.4%) was found in the intra-operative setting when recording the electrically evoked compound action potential threshold per patient. The success rate per patient was significantly lower (53.4%) in the post-operative setting. Correlations between the intra- versus the post-operative ECAP thresholds were statistically significant for all electrodes tested. The ECAP thresholds were not significantly different for the two settings. The intra-operative setting is preferable for acquisition of the ECAP threshold.

Action Potentials↗
PubMed1993

[Intra- and postoperative cerebral blood flow in patients with subarachnoid hemorrhage from a ruptured aneurysm].

The CBF of eight patients, who underwent surgery for ruptured aneurysm, was monitored using the termodiffusion technique (TDF). The device employed in this investigation allowed a continuous monitoring in "real time" of the cortical flow. The purpose of the study was to detect disorders of autoregulation, which were evaluated with the autoregulation index (AI). Autoregulation was correlated with the neurological preoperative grading, the postoperative changes of CBF (Xe133 clearance) and the outcome. The results of this preliminary study showed a correlation between these parameters and stressed the value of CBF monitoring during surgery.

Adult↗
PubMed1996

Intraoperative progress reports decrease family members' anxiety.

The researcher used a four-group quasi-experimental posttest design to examine the effect of intraoperative progress reports on 200 family members' anxiety. Group one (ie, control group) received standard perioperative care, which did not include intraoperative progress reports. Group two received in-person progress reports from perioperative nurses. Group three received an "attention" protocol (ie, checklist explaining hospital routines, waiting room procedures). Group four received progress reports delivered by telephone. The researcher compared family members' state anxiety scores, mean arterial pressures (MAPs), and heart rates measured halfway during their relatives' surgical procedures, measuring these dependent variables after providing the interventions. The in-person intraoperative progress report group reported lower state anxiety scores (P < .001) and had significantly lower MAPs and heart rates (P < .05) than the other three groups. In-person progress reports appear to be the most beneficial perioperative nursing intervention for reducing family members' anxiety during the intraoperative waiting period.

Adolescent↗
PubMed1995

Effects of intraoperative progress reports on anxiety levels of surgical patients' family members.

A three-group quasi-experimental posttest-only design was used to examine the effectiveness of intraoperative progress reports by comparing family members' state-anxiety score, mean arterial pressure level (MAP), and heart rate during elective surgical procedures. Control-group family members (n = 50) received usual care. Family members in the experimental group (n = 50) received a 5- to 10-minute progress report protocol about halfway through a surgical procedure. An additional group of family members (n = 50) received an attention protocol. Family members in the experimental group reported lower state-anxiety scores (p < .001) and had significantly lower MAP levels (p < .001) and heart rates (p < .01) compared with the control and attention groups. Progress reports appear to be a beneficial independent nursing intervention for reducing anxiety in family members during the intraoperative waiting period.

Adult↗
PubMedDate not supplied

[Effects of various rehydration periods on the stability and water content of bone transplants following freeze-drying, gamma sterilization and lipid extraction].

UNLABELLED: Several studies demonstrated the necessity of rehydration of lyophilized bone allografts prior to implantation. The purpose of the presented study was to evaluate the influence of different rehydration periods on the stability of human cortical lyophilized and gamma-irradiated allografts, the capability of lyophilized bone for rehydration, as well as the effects of lipid extraction on rehydration. Breaking strength of lyophilized irradiated cortical bone after different rehydration periods (0.5, 1, 2, 4, 8 hours) showed no significant difference. Weight reduction after lyophilization of human femoral heads was between 7.6% and 41%. Further weight reduction occurred after lipid extraction (38.7%). Total weight loss was 56.9%. There was a significant influence of intraosseous lipid content on the rehydration capability. After lyophilization alone the rehydration weight after 8 hours was only 18.1%, whereas after lipid extraction the weight increase was 43% after 0.5 hours, 36.4% after 1 hour, 57.6% after 2 hours, 60% after 4 hours, and 92.7% after 8 hours. CLINICAL RELEVANCE: Based on the presented data rehydration time of 0.5 hours seems to have no disadvantage compared to longer time periods concerning breaking strength. Therefore a longer intraoperative time period seems not to be necessary. This is of advantage for a possible secondary contamination while the allograft is rehydrated. Rehydration after lipid extraction is more effective than rehydration after lyophilization alone. However, the question whether lipid extraction alter bone stability has to be proved in further studies.

Bone Transplantation↗
PubMedDate not supplied

Facial nerve function after cerebellopontine angle surgery and prognostic value of intraoperative facial nerve monitoring: a critical evaluation.

PURPOSE: Facial nerve monitoring is often used to predict postoperative facial function after acoustic neuroma tumor removal. In this study, three methods of predicting facial nerve function were compared. These methods used various parameters of the evoked electromyographic monitoring. MATERIALS AND METHODS: Thirty-four patients who underwent surgery for acoustic neuroma were retrospectively reviewed. Amplitude of ongoing electromyographic activity, stimulation current thresholds, and the amplitude of evoked response were analyzed. The predictive value of the three methods was compared with actual postoperative facial nerve function. RESULTS: One method predicted the final postoperative facial function in 90% of the patients, one method in 84%, and the final method failed to predict the final VIIth nerve function in patients with current stimulation thresholds greater than 0.05 mA. CONCLUSION: Analysis of prognostic value showed that one of the three studied proved superior in predicting facial nerve function.

Adult↗
PubMed2003

Intraoperative monitoring of cochlear nerve compound action potential in cerebellopontine angle tumour removal.

Cochlear nerve compound action potential (CNAP) provides a real-time auditory evoked potential. Because of technical difficulty, CNAP monitoring has not been popular during the removal of cerebellopontine angle (CPA) tumour. To clarify the efficiency of intraoperative CNAP monitoring, we designed an intracranial electrode for CNAP monitoring and performed the simultaneous monitoring of CNAP and auditory brainstem response (ABR) in 10 patients undergoing CPA tumour removal in an attempt to preserve hearing. ABR recordings during microsurgical tumour removal were unsatisfactory in 6 patients because of severe artifacts. Reliable CNAP recordings were obtained without artifacts in all 10 patients throughout surgery. Eight patients preserved useful hearing after tumour removal, and the CNAP amplitude reflected the postoperative hearing. The newly designed intracranial electrode enables CNAP monitoring predicting the postoperative hearing more reliably than ABR. CNAP monitoring is efficient to improve the hearing preservation rate following CPA tumour removal.

Action Potentials↗
PubMed2005

Dreaming during anaesthesia in patients at high risk of awareness.

Dreaming during anaesthesia is commonly reported but remains poorly understood. In this study, adult surgical patients at high risk of awareness were randomly assigned to receive bispectral index (BIS)-guided anaesthesia or routine care, and were interviewed about dreaming three times postoperatively. Dreaming patients (n = 134) were compared with all other patients who were interviewed at least once (n = 2251). Intraoperative dreaming was reported by 4.2%, 3.9% and 3.4% of patients at 2-4 h, 24-36 h and 30 days after surgery, respectively. Fewer BIS-monitored patients reported intra-operative dreaming at 2-4 h than control patients (2.7% vs. 5.7%; p = 0.004). Reports of dreaming were similar in the two groups at 24-36 h and 30 days. Dreaming patients were younger (p = 0.001); healthier (p < 0.001) and more likely to be women (p < 0.001), and were less satisfied with anaesthetic care (p = 0.004) than other patients.

Adult↗
PubMed2005

Hemodynamic changes during laparoscopic gastric bypass procedures.

HYPOTHESIS: Significant detrimental intra-operative hemodynamic and respiratory changes occur in the morbidly obese during laparoscopic gastric bypass. DESIGN: Case series. SETTING: Tertiary care university hospital. PATIENTS: Thirteen patients, 10 women and 3 men, undergoing uncomplicated laparoscopic gastric bypass for morbid obesity. INTERVENTIONS: Using a pulmonary artery catheter and an arterial line, we intraoperatively monitored hemodynamic and respiratory parameters. Parameter values were recorded at set points of the procedure, and the changes were statistically analyzed. RESULTS: Significant hemodynamic and respiratory changes, mostly unfavorable, occur in the morbidly obese when creating the pneumoperitoneum in preparation for laparoscopic gastric bypass. The hemodynamic changes are attenuated when the patient is placed in the reverse Trendelenburg position and almost completely corrected when the abdomen is deflated at the completion of the procedure. The respiratory changes are more persistent. CONCLUSIONS: Laparoscopic gastric bypass surgery for morbid obesity leads to a number of predominantly detrimental, if temporary, respiratory and hemodynamic changes, which are most pronounced at the time of creation of the pneumoperitoneum. In the presence of significant cardiopulmonary comorbidities, the use of invasive intra-operative hemodynamic monitoring of the morbidly obese undergoing laparoscopic gastric bypass appears therefore justified.

Adult↗
PubMed2006

Intraoperative and postoperative evaluation of cavitation in mechanical heart valve patients.

BACKGROUND: Cavitation has been claimed partly responsible for the increased risk of thromboembolic complications, hemolysis, and fatal valve failure seen in mechanical heart valve patients. In vivo studies have investigated cavitation using high-pass filtering of the high-frequency pressure fluctuations with the root mean square values as an assessment of intensities. In vitro studies have shown that this well-known method may not be ideal owing to loss of data as a consequence of filtering, and because it requires a priori knowledge of the valve resonance pattern. Therefore, a new method has been developed, which decomposes the signal into nondeterministic (cavitation) and deterministic (valve resonance) signal components, and hence decreases data loss. This study aimed to evaluate cavitation in patients with mechanical, biological, and native heart valves both intraoperatively and postoperatively using the new method. METHODS: High-frequency pressure fluctuations were measured by a hydrophone intraoperatively and postoperatively in 14 patients with mechanical valves, 10 patients with normal aortic valves, and 5 patients with bioprosthesis. The total signal energy was evaluated as nondeterministic and deterministic energies. RESULTS: Nondeterministic energies were verified both intraoperatively and postoperatively in all patients who had a mechanical valve; this finding confirms the cavitation potential of mechanical valves. None of the data recorded in patients with bioprosthetic or native valves contained nondeterministic energy. CONCLUSIONS: The study confirms the presence of cavitation in mechanical heart valve patients using the nondeterministic energy of high-frequency pressure fluctuations as a quantitative measure of cavitation both intraoperatively and postoperatively.

Acoustics↗
PubMedDate not supplied

Intraoperative ultrasonography in urologic oncology.

Ultrasonography is a powerful nonionizing imaging modality that has generally been underused by American Urologists in the past. Innovative investigators and clinicians, however, are realizing the great potential of ultrasonography and are applying it increasingly not only in the clinic but in the operating room. In this commentary we outline some of the current and future uses of intraoperative ultrasonography in urologic oncology.

Diagnostic Imaging↗
PubMed2000

Role of nitric oxide in a temperature dependent regulation of systemic vascular resistance in cardiopulmonary bypass.

OBJECTIVES: Nitric oxide is the most potent vasodilator among inflammation-mediated vasoactive substances. Tepid cardiopulmonary bypass has been known to maintain low vascular resistance and nitric oxide may also be involved. There has been no previous clinical study elucidating a role of nitric oxide in a temperature dependent regulation of systemic vascular resistance in cardiopulmonary bypass. METHODS: Thirty-one patients who underwent valvular surgery were randomly divided into two comparable groups; consisting of the hypothermic cardiopulmonary bypass (28 degrees C:14 patients) and the tepid cardiopulmonary bypass group (34 degrees C:17 patients). The serum levels of nitric oxide (NO(2)(-)+NO(3)(-)), prostaglandin E(2), bradykinin, 6-keto PGF1alpha, thromboxane B(2), endothelin-1, systemic vascular resistance index were measured before, 0, 12 and 24 h after cardiopulmonary bypass. RESULTS: The pattern of change in systemic vascular resistance index and nitric oxide during and after cardiopulmonary bypass were significantly different between the two groups (P=0.0008, P=0.02). The tepid group showed significantly lower levels of systemic vascular resistance index after cardiopulmonary bypass than the hypothermic group (0 h: 2278+/-735 vs. 4387+/-1289, 12 h: 1827+/-817 vs. 2817+/-1146 and 24 h: 1690+/-548 vs. 2761+/-641 dyne s cm(-5) m(2), P=0.0001, P=0.03, P=0. 0006). The nitric oxide levels were significantly higher at 0, 12 and 24 h after cardiopulmonary bypass in the tepid group than those in the hypothermic group (84.7+/-33.3 vs. 46.3+/-18.1, 69.8+/-31.1 vs. 40.1+/-17.5 and 80.1+/-38.5 vs. 39.1+/-15.6 micromol/l, P=0.008, P=0.03, P=0.01). The prostaglandin E(2) levels in the tepid group was significantly higher just after cardiopulmonary bypass than that in the hypothermic group (37.3+/-20.0 vs. 15.8+/-8.6 pg/ml, P=0.02). The bradykinin level in the hypothermic group was significantly higher just after cardiopulmonary bypass than that in the tepid group (2.40+/-0.32 vs. 1.85+/-0.21 log(10) (pg/ml), P=0.005). Only nitric oxide showed a significant negative correlation with the systemic vascular resistance index both during and after cardiopulmonary bypass (r=-0.60, P<0.0001) as compared with prostaglandin E(2) and bradykinin. CONCLUSIONS: These findings demonstrated that serum nitric oxide levels in tepid cardiopulmonary bypass were significantly higher than those in hypothermic cardiopulmonary bypass. Nitric oxide correlated with systemic vascular resistance. Thus, nitric oxide may play a pivotal role in a temperature dependent regulation of systemic vascular resistance in cardiopulmonary bypass.

Biomarkers↗
PubMed1996

Contralateral evoked brainstem auditory potentials as an indicator of intraoperative brainstem manipulation in cerebellopontine angle tumors.

Brainstem auditory evoked potentials (BAEP) were studied during operations to remove acoustic tumors using the retromastoid approach. BAEP were elicited from the side contralateral to the tumor, and changes in the latencies of peaks III and V of the BAEP were compared with changes in cardiovascular parameters throughout the operation. When the changes in the determined cardiovascular parameters were related to surgical manipulations, the related changes in the latencies of peaks III and V of the BAEP were more consistent than the changes in the cardiovascular parameters and they tended to occur earlier than the changes noted in the cardiovascular parameters.

Adult↗