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PubMed1989

Evaluation of a blood gas and chemistry monitor for use during surgery.

An observational study was performed to evaluate a new blood gas and chemistry monitor (GEM-6 Diamond Sensor Systems, Ann Arbor, Michigan) in nine patients during cardiac surgery. Paired blood samples were analyzed by the instrument under test and by standard clinical laboratory instruments. The differences between the measurements of the new and the standard instruments are summarized as follows (mean +/- standard deviation, units of measure, number of samples): pH (-0.039 +/- 0.02, 154); PCO2 (2.63 +/- 1.8 mmHg, 154); venous PO2 (-2.0 +/- 3.0 mmHg, 72), hematocrit (4.7 +/- 2.7%, 98), potassium (0.18 +/- 0.13 mmol, 100), and ionized calcium (0.195 +/- 0.11 mmol, 100). Because the differences in arterial PO2 measurements were markedly heteroscedastic, a logarithmic transformation was employed, which upon retransformation gave the test instrument's 95% confidence limits as within 5.1% below to 46% above the nominal value on 82 samples. However, on the 14 samples having nominal values below 165 mmHg (the upper limit of the calibrated range of the GEM-6) the 95% confidence limits were from 5.4% below to 23.6% above the nominal reading. No failures of the test instrument occurred during the evaluation, and quality control standards run before, midway through, and again after sampling from each patient all gave readings within the manufacturer's tolerance. For all variables except hematocrit and ionized calcium, this instrument matches the values from the laboratory well enough over the clinically important range to supplant it for intraoperative monitoring purposes.

Acid-Base Equilibrium↗

PubMed2000

Supraventricular arrhythmia following lung resection for non-small cell lung cancer and its treatment with amiodarone.

OBJECTIVE: From January 1998 to February 1999, 160 patients undergoing lung resection for non-small cell lung cancer were studied to define factors that increase the risk of postoperative supraventricular arrhythmia (SA) and to assess the effectiveness of amiodarone as an antiarrhythmic drug. METHODS: All patients were monitored intraoperatively and postoperatively up to day 3. Onset of SA was documented with ECG. Amiodarone was administered to those who developed SA with a loading dose of 5 mg/kg in 30 min and a maintenance dose of 15 mg/kg in 24 h. RESULTS: Mean age was 64 years (range 27-83 years). There were nine wedge resections, six segmentectomies, 127 lobectomies and 18 pneumonectomies. Twenty-two patients (13%) had SA, all of which were atrial fibrillations. The incidence of supraventricular arrhythmia with pneumonectomy and lobectomy was 33 and 12%, respectively (P=0.02). None of the patients who had a minor resection developed SA. The peak incidence of onset of SA occurred on postoperative day 2 and lasted from 1 to 12 days (average 3.4 days). Sinus rhythm was achieved with amiodarone in 20 patients (90.9%) with no side effects. Two patients received electrical cardioversion because hemodynamically unstable. Mean preoperative pO(2) and pCO(2) were lower in patients with SA: pO(2) 80.8 vs. 85 mmHg (P=0.04); pCO(2) 35.5 vs. 38 mmHg (P=0.01). Patients with concomitant cardiopulmonary diseases presented an odds ratio for postoperative arrhythmia of 12.4 (confidence interval 4. 5-34.1) (P<0.0001). CONCLUSION: Concomitant cardiopulmonary diseases, lower pO(2), pCO(2) and extent of surgery increase the risk of postoperative SA after lung resection for non-small cell lung cancer. Cardiac monitoring in patients at risk is recommended. Amiodarone was both safe and effective in establishing and maintaining sinus rhythm.

Adult↗

PubMed1988

Intermittent coronary sinus occlusion in humans: pressure dynamics and calculation of diagnostic quantities.

Pressure controlled intermittent coronary sinus occlusion (PISCO) was applied in 30 patients undergoing coronary artery bypass surgery. The occlusion and release times were manually adjusted according to visual control of the intraoperatively monitored coronary sinus pressure. In six patients the coronary sinus measurements were additionally digitised with a personal computer before postoperative mathematical analysis, which comprised automatic detection of systolic peaks, diastolic troughs, and the calculation of derived quantities. The purpose of the analysis was (a) to assess quantitatively human coronary sinus pressure dynamics, (b) to determine whether visual control and interpretation of coronary sinus pressure rise could be replaced by a mathematical model, and (c) to ascertain whether the occlusion and release cycle lengths were adequate. Numerical estimates for intraindividual and interindividual spread of calculated quantities were produced, the mathematically obtained results were related to a possible physiological interpretation, and the most efficient method of statistical analysis was ascertained. These results form the numerical basis for a closed loop adjustment of pressure controlled intermittent coronary sinus occlusion cycling.

Aged↗

PubMed1988

[Evoked potentials and inhalation anesthetics].

Intraoperative monitoring of evoked potentials can be affected by various factors including volatile anaesthetics. These effects have to be considered in order to give correct interpretations of the obtained data. Visual evoked potentials (VEP) and auditory evoked potentials (AEP) will show strong alterations under general anaesthesia whereas brainstem auditory evoked potentials (BAEP) are slightly affected. The effects of nitrous oxide, halothane, enflurane, and isoflurane on somatosensory evoked potentials (SEP) after median nerve stimulation were studied in 35 healthy adult patients. pCO2 and tympanic membrane temperature were held constant. Simultaneous cervical and cortical SEP recording was performed using surface electrodes. After induction of anaesthesia SEP were recorded during normoventilation with 100% oxygen and after inhalation of 66.6% nitrous oxide. 10 patients received halothane at inspired concentrations of 0.5, 1.0, 1.5, and 2.0%. After nitrous oxide had been replaced by oxygen, halothane was reduced in steps of 0.5%. SEP were recorded at the end of each period (15 min). Equipotent doses of enflurane or isoflurane were administered to 15 and 10 patients, respectively. Nitrous oxide depressed early cortical SEP amplitude. Halothane, enflurane, and isoflurane caused dose dependent increases of latencies. Reduction of amplitude was most pronounced with isoflurane. Using high doses of enflurane in oxygen cortical SEP showed unusual high amplitudes associated with marked increases of latencies. Even under high concentrations of volatile anaesthetics cervical SEP were minimally affected. The effects of anaesthetic gases have to be considered when SEP are recorded intraoperatively.

Anesthesia, Inhalation↗

PubMed1986

[Effects of halothane on sensory evoked potentials].

Intraoperative monitoring of central nervous system functions is useful for safe neurosurgical operations. For such a purpose, some kinds of sensory evoked potentials play significant roles, but their reliability during general anesthesia have not yet been established. The authors conducted experimental and clinical studies to reveal effects of halothane, a most popular anesthetic, on sensory evoked potentials. Eight adult cats, weighing 2.8-4.0 kg, were induced to anesthesia with thiopental and ether, and after tracheostomy and venous cannulation, they were immobilized with succinylcholine and artificially ventilated with mixture of oxygen, nitrous oxide halothane. The concentration of halothane was increased up to 4.0% by 0.5% steps. The body temperature, systemic blood pressure and carbon dioxide concentrations in expires gas were monitored continuously, and maintained within normal ranges as much as possible. The hypotension induced by halothane was easily corrected by dopamine infusion initially, but later became difficult to be controlled as the halothane concentration increased. In each concentration, short latency somatosensory evoked potentials by median nerve stimulations (SL-SEP), and brain stem auditory evoked potentials (BAEP) were recorded. Active electrode was placed on the bregma, and reference electrodes were placed on a hindlimb for SL-SEP, on the tongue for BAEP recordings. Peak amplitudes of SL-SEP were gradually decreased and finally disappeared without apparent dose dependency. Relatively the peaks with longer latencies were more affected than those with shorter latency such as P1 and N1. In BAEP, decrement of the amplitude was apparent in the peaks with longer latencies with an obvious dose dependency.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗

PubMed1988

Evaluation of laser- and radiofrequency-generated dorsal root entry zone lesions in the cat.

The current study was designed to measure and compare the size of dorsal root entry zone lesions made in the midthoracic spinal cord of anesthetized cats with a carbon dioxide laser and the radiofrequency (RF) probe utilizing currently employed clinical parameters. Cats were monitored intraoperatively with somatosensory evoked potentials (SSEPs) derived from stimulation of the ipsilateral posterior tibial nerve in order to assess the acute effect of lesion production on function within the ipsilateral dorsal column. Daily postoperative neurologic evaluations were recorded. The lesioned segments of spinal cord from sacrificed animals were examined histologically to determine the extent of cord injury at 1 and 30 days. SSEPs remained normal for the laser group, but were uniformly attenuated or lost in the RF group. Neurologically, the laser group fared better, with only a mild transient monoparesis, compared to a persistent moderate paraparesis for the RF group. On histologic examination, the depths of the laser and electrode lesions were similar, but the RF lesions showed more lateral spread. Laser lesions comprised 4.4 +/- 1.6% of the cross-sectional area of the spinal cord whereas the RF lesions occupied 22.8 +/- 4%. These findings demonstrate that at the parameters employed, the carbon dioxide laser produces smaller lesions than does the RF electrode.

Animals↗

PubMed2002

[Cardiovascular stress in laparoscopic surgery].

AIM: To evaluate response of cardiovascular system in laparoscopic surgery. The main aim was: 1--comparison of healthy subjects and morbid obese population, 2--comparison of healthy subjects and cohort of patients with organic cardiopathy. Secondly we compared the influence of the operation position. PATIENTS AND METHODS: Patients (n = 17) were divided into 3 subgroups:--Control group of "normal" subjects: mean age 36.8 +/- 11.2 years; BMI 25.33 +/- 3.62; BSA 1.84 +/- 0.21 m2; two men and four women; op. diagnosis: 3x cholecystectomy, 1x appendectomy, 1x inguinal herniotomy, 1x hiatal hernia operation. --Group of patients with morbid obesity: mean age 38 +/- 8.1 years; BMI 45.82 +/- 7.54!; BSA 2.66 +/- 0.32 m2; one man and five women; all of them were operated for obesity (laparoscopic gastric banding).--Group of patients with severe cardiopathy: mean age 64.0 +/- 11.55; BMI 26.4 +/- 4.09; BSA 1.89 +/- 0.23; three men and two women; card. diagnosis: 2x aortic stenosis, 1x combined aortic valvulopathy, 1x aortic stenosis with secondary mitral regurgitation, 1x secondary mitral regurgitation (both caused by coronary artery disease); op. diagnosis: 4x cholecystectomy; 1x extraction of catheter for peritoneal dialysis. The method of our examination was transesophageal echocardiography with use of omni planar sond with continual monitoring of each patient. Our data are based on repeated measurements (3x minimal for each state and each patient) before and after peritoneal cavity insufflation and third after positioning of patient (in Trendelenburg or Fowler position). Examinations were recorded and data analysed off-line. Following parameters were analysed: mean age, BMI, BSA, heart rate, mean arterial pressure (MAP), ejection fraction of left ventricle (EF), E/A ratio of transmitral flow, cardiac output (CO), cardiac index (CI), systemic (peripheral) vascular resistance (SVR) and pressure-rate-product (PRP). For statistical analysis were used: ANOVA tests, t-tests with Benforroni correction and Friedman's tests. RESULTS AND DISCUSSION: In comparison of normal and obese patients statistically significant differences were found (after exclusion of BMI and BSA) in cardiac output values, after recalculation on body surface (cardiac index) remained only non-significant trend to fall. Differences between control group and group of cardiacs were also non significant with exclusion of E/A ratio of transmitral flow. This result we explain by pseudonormalization. All 17 operations were successfully done without any complication. CONCLUSIONS: Our data were obtained on relatively small cohort of patients but the number of patients was respected by statistics and results might be borderline but significant. Laparoscopic gastric band (operation is done in semi-sitting position) in morbid obese patients is well tolerated without any differences in comparison to healthy population. The population of patients with severe organic cardiopathy needs careful approach. Our data are favourable but significant change in the left ventricle filling together with non-significant hemodynamic disadvantageous trends in EF, CI and MAP requires care. Further investigations are needed and with intraoperative monitoring (transesophageal echocardiography is preferred) can be considered as safe.

Adult↗

PubMed1994

[Surgery of primary hyperparathyroidism by unilateral approach under local anesthesia and intraoperative determination of PTH 1-84].

Between July 89 and June 92, 70 patients with primary hyperparathyroidism underwent adenomectomy by unilateral incision under local anesthesia (Ul/LA), without exploration of the remaining glands. The procedure was carried out with intraoperative monitoring of urinary cyclic AMP (n = 35), Calcemia was measured 6-monthly for one year in every patient. 62 (88.6%) patients were cured after Ul/LA, whereas 5 patients required conversion to bilateral cervicotomy under general anesthesia because of abnormal hormonal levels, thus giving an overall success rate of 97% (67/70). The reasons for treatment failure of Ul/LA included misleading conclusions of cervical ultrasonography (n = 5), agitation of the patient (n = 1) and deep localization of the adenoma (n = 1). When cervical ultrasonography is suggestive of a parathyroid adenoma in expert hands, the probability of a second localization or associated hyperplasia is very low, so that adenomectomy by Ul/LA can be attempted safely, provided that the serum level of intact parathyroid hormone returns to normal values within one hour following resection. In our experience, parathyroidectomy by Ul/LA should not be considered in case of non conclusive ultrasonography, familial history pf hyperparathyroidism of MEN-I, ultrasonic evidence of several enlarged glands or associated thyroid nodule requiring simultaneous treatment.

Adult↗

PubMed1987

Monitoring facial EMG responses during microvascular decompression operations for hemifacial spasm.

Facial electromyographic (EMG) responses were monitored intraoperatively in 67 patients with hemifacial spasm who were operated on consecutively by microvascular decompression of the facial nerve near its exit from the brain stem. At the beginning of the operation, electrical stimulation of the temporal or the zygomatic branch of the facial nerve gave rise to a burst of EMG activity (autoexcitation) and spontaneous EMG activity (spasm) that could be recorded from the mentalis muscle in all patients. In some patients, the spontaneous activity and the autoexcitation disappeared after the dura was incised or when the arachnoid was opened, but stimulation of the temporal branch of the facial nerve caused electrically recordable activity in the mentalis muscle (lateral spread) with a latency of about 10 msec that lasted until the facial nerve was decompressed in all but one patient, in whom it disappeared when the arachnoidal membrane was opened. When the facial nerve was decompressed, this lateral spread of antidromic activity disappeared totally in 44 cases, in 16 it was much reduced, and in seven it was present at the end of the operation at about the same strength as before craniectomy. In four of these last seven patients there was still very little improvement of the spasm 2 to 6 months after the operation; these four patients underwent reoperation. In two of the remaining three patients, the spasm was absent at the 3- and 7-month follow-up examination, respectively, and one had mild spasm. Of the 16 patients in whom the lateral spread response was decreased as a result of the decompression but was still present at the end of the operation, 14 had no spasm and two underwent reoperation and had mild spasm at the last examination. Of the 44 patients in whom the lateral spread response disappeared totally, 42 were free from spasm and two had occasional mild spasm at 6 and 13 months, respectively, after the operation. Monitoring of facial EMG responses is now used routinely by the authors during operations to relieve hemifacial spasm, and is performed simultaneously with monitoring of auditory function for the purpose of preserving hearing. The usefulness of monitoring both brain-stem auditory evoked potentials recorded from electrodes placed on the scalp and compound action potentials recorded directly from the eighth cranial nerve is evaluated.

Electromyography↗

PubMed1983

Definition of the safe lower limits of aortic resection during surgical procedures on the thoracoabdominal aorta: use of somatosensory evoked potentials.

The technique of intraoperative monitoring of somatosensory evoked potentials was applied to a canine model of spinal cord ischemia in an attempt to determine the safe lower limits of aortic resection during thoracic aortic surgery. Fifteen animals underwent left thoracotomy with institution of partial left atrial/femoral artery bypass for maintenance of distal aortic perfusion after proximal descending thoracic aortic exclusion. In Group I animals (n = 6, control), no further interventions were performed so that the effect of exclusion of vessels noncritical to spinal cord blood supply could be assessed by measurements of spinal cord blood flow and somatosensory evoked potentials. In Group II animals (n = 8), the level of distal aortic exclusion was progressively lowered until loss of somatosensory evoked potential (critical vessel exclusion) occurred. The effect of critical vessel exclusion on spinal cord blood flow was then assessed. Exclusion of multiple vessels noncritical to spinal cord blood supply (Group I) had no effect on spinal cord blood flow or function (somatosensory evoked potentials). Exclusion of vessels critical to spinal cord blood supply resulted in significant spinal cord ischemia (83.4% flow reduction, probability [p] less than 0.05 versus baseline) and ischemic spinal cord dysfunction (loss of somatosensory evoked potential).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Evaluation of the palmar circulation by pulse oximetry.

The usual method of substantiating collateral circulation of the hand is with Allen's test. We used the pulse-detecting capability of the pulse oximeter to assess the presence of collateral circulation of the hand. Thirty-one patients undergoing radial artery cannulation for intraoperative monitoring were evaluated before cannulation with a modified Allen's test and by pulse oximetry. After the collateral circulation of the hand was tested by the modified Allen's test, a pulse oximeter probe was placed on the index finger. Both radial and ulnar arteries were occluded until no perfusion was detected by the pulse oximeter. The test was repeated twice on each hand, once for each artery. The time to reperfusion after arterial release was recorded. Reperfusion times greater than 15 seconds were considered abnormal. This sequence was repeated postoperatively after the radial artery cannulae were removed. A total of 68 tests were performed before cannulation; 3 showed an abnormal Allen's test, a finding confirmed by pulse oximetry evaluation. The Allen's test was indeterminate 13 times. In all of these cases, pulse oximetry demonstrated collateral blood flow. When collateral circulation was determined to be present by Allen's test, it was also found to be present with pulse oximetry. Three days after cannulation was discontinued, 8 patients had abnormal Allen's test results, a finding again confirmed by pulse oximetry evaluation. Of 15 patients with indeterminate Allen's test results, 12 had collateral blood flow determined by pulse oximetry and 3 had abnormal results. The ability of pulse oximetry to detect collateral circulation was significantly different (P less than 0.001) when compared with Allen's test both before and after radial artery cannulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

The superiority of continuous cold blood cardioplegia in the metabolic protection of the hypertrophied human heart.

The effects of sanguineous and asanguineous cardioplegia on the generation of myocardial acid in the hypertrophied human heart during aortic clamping and reflow were elucidated by continuous intraoperative monitoring of myocardial pH in 42 patients undergoing valve replacement, with or without coronary bypass. The patients were divided into three groups: Group I (n = 14) received intermittent crystalloid cardioplegia; group II (n = 14) received intermittent blood cardioplegia; and group III (n = 14) received continuous blood cardioplegia. The groups were matched according to six previously elucidated determinants of myocardial acidosis. Measurements were made of myocardial pH, hydrogen ion concentration ([H+]), and the difference in pH units between myocardial pH and the pH of neutrality of water at the corresponding temperature (delta pHn). Throughout aortic clamping, myocardial pH in groups I and II fell significantly by 0.46 +/- 0.08 and 0.15 +/- 0.07 units, respectively (p less than 0.001) between the groups). In contrast, myocardial pH remained statistically unchanged throughout aortic clamping in group III (p less than 0.001 compared to groups I and II). Similar relationships were observed in [H+] and delta pHn during aortic clamping. During the early reflow, myocardial acidosis was observed in all three groups and delta pHn in group III increased from -0.26 +/- 0.10 at the end of aortic clamping to -0.57 +/- 0.07 during reperfusion (p less than 0.03). Patients in groups II and III required significantly less inotropic and mechanical cardiac support than patients in group I (p = 0.017). Hence, although continuous blood cardioplegia does not completely prevent acid accumulation during reflow, it provides better metabolic protection of the hypertrophied human heart than either intermittent crystalloid or intermittent blood cardioplegia.

Aged↗

PubMed1994

Prediction of intracerebral haemorrhage after carotid endarterectomy by clinical criteria and intraoperative transcranial Doppler monitoring.

Intracerebral haemorrhage is a serious complication after carotid endarterectomy. We tried to identify predictors of this event. Two-hundred-and-thirty-three operations were selected from a total of 280 because of reliable intraoperative transcranial Doppler data with regards to the increase of peak blood flow velocities and pulsatility indices in the ipsilateral middle cerebral artery after release of the internal carotid artery cross-clamp. We also recorded the occurrence of unilateral throbbing headache or hypertension after the operation. Five patients developed an intracerebral haemorrhage after the operation. Seventeen patients developed headache or hypertension after surgery, four of whom developed an intracerebral haemorrhage (p < 0.001; Fisher's exact test). The positive predictive value of headache, hypertension, or both, for intracerebral haemorrhage was 24% (diagnostic gain 22%). The negative predictive value, sensitivity and specificity were 99, 80 and 94%, respectively. The increase of peak blood flow velocities and pulsatility indices in patients who developed intracerebral haemorrhage was significantly higher than in patients who did not (p < 10(-5); one-way ANOVA). With appropriate cut-off levels for the increase of peak blood flow velocities (> or = 175% increase) or pulsatility indices (> or = 100% increase) after release of the cross-clamps, the positive predictive value of intraoperative transcranial Doppler for intracerebral haemorrhage was 100% (diagnostic gain 98%). The negative predictive value, sensitivity and specificity were 99, 80 and 100%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2006

Intraoperative motor-evoked potential monitoring in scoliosis surgery: comparison of desflurane/nitrous oxide with propofol total intravenous anesthetic regimens.

STUDY DESIGN: A prospective, randomized study in a large general hospital setting. BACKGROUND: During spinal surgery, monitoring motor-evoked potentials (MEPs) is a means of assessing the intraoperative integrity of corticospinal pathways. However, MEPs are known to be sensitive to the effects of anesthetic agents. OBJECTIVE: To compare the use of desflurane or total intravenous anesthetic regimens (TIVA) with multipulse cortical stimulation for intraoperative monitoring (IOM). METHODS: Twenty consecutive patients (10 in each arm) undergoing scoliosis correction surgery were randomly assigned to 2 equal groups receiving desflurane or TIVA. Inhalational anesthesia was maintained using 66% nitrous oxide in oxygen and a mean end-tidal desflurane concentration of 3.4%. For TIVA, continuous intravenous infusion of propofol was used. For analgesia, fentanyl and morphine were given when required for both groups. Cortical stimulation was achieved with 2 bipolar direct current stimulators connected in parallel by jumper cables. Five equivalent pulses 0.5 ms in duration at 4 ms intervals were delivered at C1C2 positions. MEP recordings were made in the abductor hallucis (AH) and tibialis anterior (TA) with needle electrodes. RESULTS: Reproducible MEPs were obtained throughout the operation in all 20 cases, with up to 80 mA per stimulator. Before insertion of pedicle screws, mean MEP amplitudes (SD) obtained were 85 (19) and 21.7 (10.8) mV for AH and TA, respectively, using desflurane. With TIVA, amplitudes were 56.7 (28.4) and 59.1 (24.5) mV, respectively. Both muscle MEP amplitudes were significantly different using different anesthetic regimens (P < 0.05 for all). AH MEP amplitudes obtained with desflurane were significantly larger than TA amplitudes (P < 0.0001). No complications were reported intraoperatively and postoperatively. CONCLUSIONS: This is the first study comparing the use of desflurane and TIVA showing that both anesthetic regimens allowed successful intraoperative monitoring useage throughout the procedures. For MEP recording, the AH was the preferred muscle with a desflurane anesthetic regimen.

Adolescent↗

PubMed1995

Internal carotid artery resection for invasion of malignant tumors.

BACKGROUND: To study the preoperative investigation and outcome of patients who underwent resection of the internal carotid artery for malignant disease. A retrospective analysis using a chart review of these patients was performed, and the results were analyzed. All patients were treated by one of us (U.K.N.) at the University of California-Davis Medical Center, Sacramento. A population of 18 patients who underwent a transcervical, transpetrosal, or petrocavernous resection of the internal carotid artery from 1976 to 1993 was studied. Preoperative study consisted of four-vessel arteriography, balloon test occlusion, electroencephalographic intraoperative monitoring, and, after 1990, single-photon emission computed tomographic scanning. Disease-free interval and neurologic complications were assessed. RESULTS: Two patients were alive and well without disease at 6 and 9 months postoperatively. One patient was alive and well at 12 months, and three have survived more than 2 years without recurrent tumor. Eleven patients died within 1 year of surgery (three postoperatively, six of recurrent disease, and two of unknown causes). One patient died of disease at 14 months. CONCLUSIONS: Internal carotid artery invasion by malignancy portends a poor prognosis. Carotid artery resection can provide reasonable palliation. Early results of skull-base surgery on patients with intrapetrous and petrocavernous carotid artery involvement are encouraging. Balloon test occlusion and single-photon emission computed tomographic scanning provide a valuable assessment of contralateral cerebral blood flow.

Adult↗

PubMed2002

Intraoperative parathyroid hormone measurement in patients with secondary hyperparathyroidism.

HYPOTHESIS: Secondary hyperparathyroidism decreases renal clearance of parathyroid hormone (PTH). OBJECTIVE: To determine whether rapid PTH assays can be used to predict the success of a total parathyroidectomy to treat symptomatic secondary hyperparathyroidism. DESIGN: Case series from August 1 to December 31, 2000. SETTING: Tertiary referral center. PARTICIPANTS: Patients with symptomatic secondary hyperparathyroidism (n = 24) who underwent total parathyroidectomy and autotransplantation were included in the study. INTERVENTIONS: Blood samples for rapid PTH analyses were drawn from an indwelling catheter at the induction of anesthesia (baseline) and before (0 minutes), 10 minutes, and 30 minutes after the removal of the last parathyroid gland. Regular intact PTH (iPTH) assays were conducted later. MAIN OUTCOME MEASURE: If a patient's regular iPTH levels were below 65 pg/mL at 1 week or 3 months postoperatively, the operation was considered successful. RESULTS: All 24 patients had successful operations. Rapid PTH and regular iPTH correlated significantly at 0, 10, and 30 minutes. Rapid PTH levels decreased significantly at each time period and were 176 +/- 40.9 pg/mL (mean +/- SE) at 10 minutes. The percentage decrease in rapid PTH levels was 39.5% +/- 12.7% at 0 minutes, 75.1% +/- 6.2% at 10 minutes, and 91.0% +/- 0.1% at 30 minutes (mean +/- SE). A decrease of 60% or more from baseline PTH levels at 10 minutes and/or a decrease of 85% or more at 30 minutes predicted the successful removal of all parathyroid glands. CONCLUSIONS: A drop in PTH levels is delayed until 30 minutes after total parathyroidectomy; however, a rapid PTH assay 10 minutes after the removal of the last parathyroid gland is as accurate as an assay performed at 30 minutes postoperatively. Intraoperative PTH monitoring demonstrates relevant decreases in rapid PTH levels after parathyroidectomy that are similar to those previously documented in patients with primary hyperparathyroidism.

Alkaline Phosphatase↗

PubMed1996

Ambulatory parathyroidectomy for primary hyperparathyroidism.

OBJECTIVE: To evaluate whether the combined application of preoperative localization and intraoperative monitoring of intact parathyroid hormone (iPTH) levels could facilitate safe outpatient parathyroidectomy. DESIGN: Consecutive patients, who had no antecedent social or medical conditions mandating hospitalization, were prospectively offered ambulatory parathyroidectomy with a mean follow-up of 7 months (range, 1-25 months). SETTING: Tertiary care referral center PATIENTS: From 85 patients who had primary hyperparathyroidism with hypercalcemia and elevated iPTH levels, 57 were offered outpatient parathyroidectomy. Nineteen patients were asymptomatic, 3 had hypercalcemic crisis, and the others gave a history of renal stones or had complaints consistent with bone disease. INTERVENTIONS: Technetium Tc 99m sestamibi scintiscans were used for preoperative localization. Monitoring iPTH levels during parathyroidectomy quantitatively assured the surgeon (G.L.I. only) when all hyperfunctioning glands were excised. MAIN OUTCOME MEASURE: The number of patients without complications and with short operative times who were discharged without hospital admission or overnight stay. RESULTS: The combination of preoperative localization of abnormal parathyroid glands and a decline in circulating iPTH levels predicting postoperative normocalcemia after excision of all hyperfunctioning glands resulted in successful parathyroidectomy in 84 of 85 patients. A decreased operative time (average, 52 minutes) with minimal neck dissection permitted outpatient parathyroidectomy in 42 of 57 eligible patients. CONCLUSIONS: The combination of preoperative parathyroid scintiscan localization and iPTH level monitoring during surgery permitted successful parathyroidectomy in an ambulatory setting in half of a consecutive series of patients with primary hyperparathyroidism. The safety, success, and likely cost savings of this approach suggest wider application.

Adolescent↗

PubMed1999

A new technique for recording sensory conduction velocity of the inferior alveolar nerve.

A new electrophysiological technique for recording the sensory conduction velocity (SNCV) of the inferior alveolar nerve (IAN) is described. Bilateral orthodromic recordings were done in 21 healthy adults. The sensory responses of the IAN were obtained in all 42 nerves examined with silver wire or monopolar needle electrodes inserted beneath the zygomatic arc in front of the temporomandibular joint to a depth of 4-4.5 cm, near the oval foramen. A small bipolar surface electrode was used for stimulation at the mental foramen. In 3 subjects, the stimuli were additionally delivered via two monopolar needle electrodes to reduce the stimulus artifact. Single responses were usually sufficient for analysis, but, in some cases, averaging was adopted to improve the signal-to-noise ratio. Response latencies and amplitudes, SNCVs, and interside differences were measured, and the 97.5% upper and 2.5% lower prediction limits calculated for reference limits in clinical practice. This new technique provides a sensitive and objective diagnostic tool for the examination of IAN injuries, and may also be used for intraoperative monitoring of the IAN during mandibular surgery.

Adolescent↗