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At least 19 recordsLinked to original sources

Noninvasive intraoperative monitoring: a prospective study comparing Doppler systolic occlusion pressure and segmental plethysmography.

Seventy-two limbs in forty patients underwent Doppler systolic ankle pressure and Pulse Volume Recording (PVR) amplitude measurements intraoperatively. Control patients and patients undergoing abdominal aortic aneurysm (AAA) resections showed no significant decrease in Doppler systolic ankle/brachial pressure ratio (DSAB). PVR measurements were slightly decreased after declamping in the AAA patients. Femoropopliteal bypass was associated with a prompt increase in PVR and DSAB levels. In contrast, postreconstruction values in the extraanatomic (EA) and aortofemoral (AF) bypass groups were dependent upon the patency of the femoropopliteal segment. Intraoperative monitoring provides a quantitative assessment of the immediate success of arterial surgery.

Ankle

Hypnosis for monitoring intraoperative spinal cord function.

In such procedures as the Harrington operation for idiopathic scoliosis, evaluation of spinal cord function is advisable immediately after the back is straightened. The authors have used hypnosis for this procedure, as an adjunct to anesthetic management. Patients are awakened on the table, given lower extremity tests, and are then reanesthetized. The incidence of postoperative pain and other discomfort is also reduced by hypnosis.

Adolescent

Activated clotting time (ACT) monitoring of intraoperative heparinization in peripheral vascular surgery.

We conclude that (1) the activated clotting time (ACT) is an accurate method of monitoring anti-coagulation during peripheral vascular surgery and can easily be performed by a technician in the operating room or at the bedside; (2) an initial heparinizing dose of 120 to 130 units/kg is adequate in 95 per cent of the patients; (3) the ACT should be maintained at greater than twice the control values (180 to 200 seconds), which required supplementation within 2 hours in 21 per cent; (4) the response to heparin is twofold: an initial sensitivity or resistance followed by an independent and variable rate of consumption; (5) the patient's heparin dose-response curve should be used to calculate the amount of supplemental heparin needed to maintain the ACT at a safe level; (6) protamine should be given if the ACT at the conclusion of the operation is greater than 150 seconds (50 per cent of our patients); and (7) a final ACT 15 to 30 minutes postoperatively should be obtained to ensure adequate reversal or to detect heparin rebound or depletion of clotting factors.

Arteries

Monitoring of intraoperative heparinization and blood loss following cardiopulmonary bypass surgery.

Two protocols of heparin management during cardiopulmonary bypass were compared to assess the role of the activated clotting time (ACT) in relation to postoperative blood loss. The study was divided into two groups: Group I, the control group, in which 3 mg. of heparin per kilogram was given as the initial dose and maintained at a dose of 1.5 mg. per kilogram every 45 minutes during cardiopulmonary bypass, and Group II, in which the initail dose of heparin was 2 mg. per kilogram and additional dosage were based upon the ACT. We found a striking decrease in postoperative blood loss as well as a decrease in the amount of heparin administered during cardiopulmonary during cardiopulmonary bypass in Group II patients. In addition, less protamine was required to neutralize the heparin in the second group after bypass. Thus, when patients are given too much heparin, as in our control group, the effectiveness of protamine is decreased. We would like to stress the value of the ACT in controlling heparin administration as well as postoperative blood loss in cardiopulmonary bypass surgery.

Blood Coagulation

Intraoperative physiologic monitoring and management during hepatic lobectomy using the liver isolation-perfusion technic.

The high operative mortality of major hepatic resection for tumor can be improved by a technic of resection using complete vascular isolation and hypothermic perfusion of the liver. Complete clamping of the portal vein, vena cava, and hepatic artery was necessary and well tolerated. Major physiologic, biochemical, and coagulation changes, however, can occur with this technic that requires close monitoring by the anesthesiologist. With astute observation and prompt corrective measures when indicated, these changes can be minimized to enable a safe and smooth resection to be carried out.

Acid-Base Equilibrium

Intraoperative patient monitoring: a method of analyzing esophageal phonocardiograms.

The value of esophageal phonocardiography as a noninvasive monitor during anesthesia was studied in dogs. Esophageal phonocardiograms were analyzed using fast Fourier transform and least squares linear regression technics. This method has demonstrated that it is feasible to estimate two parameters of cardiac contractility--1/(PEP)2 and stroke power--and one parameter that demonstrates the state of the vasculature--total peripheral resistance. A continuous time (analog) processor that will accomplish this task is described.

Anesthesia

Monitoring of intraoperative heparinization in vascular surgery.

In 15 patients undergoing aortofemoral bypass, partial thromboplastin time (PTT) tests before and following intravenous administration of 75 U. per kilogram of heparin at zero, 30, 60, 90, and 120 minutes were determined for study of control of anticoagulant adequacy. The results demonstrate clearly that this amount provides excellent protection against thrombosis without bleeding complications. For intraoperative assay of heparin level effectiveness, the PTT test is advised. This test showed that a value of 250 percent of control still existed 75 minutes following the administration of heparin.

Aged

Intraoperative assessment of arterial reconstruction by Doppler ultrasound.

The Doppler ultrasonic velocity detector is a simple, inexpensive and versatile device for intraoperative monitoring of the integrity and hemodynamics result of vascular reconstructive surgical procedures. With this instrument, an ankle-arm systolic pressure index may be obtained before and after aortoiliac and femoral reconstructive surgical procedures. If the ankle pressure index does not increase following aortofemoral bypass and a thromboembolic vascular accident has been ruled out, it is unlikely that the patient will be significantly helped by that procedure alone. The use of a sterile Doppler probe permits qualitative assessment of arterial velocity signals following femoropopliteal bypass, carotid endarterectomy and mesenteric or renal vascular procedures. The Doppler detector may also be used to assess periorbital flow dynamics following carotid endarterectomy. Selective intraoperative arteriography can be based upon the presence of residual flow abnormalities detected by Doppler ultrasound.

Aorta

Surgical management of jugular foramen meningiomas: a function-prioritized perioperative workflow.

OBJECTIVE: Jugular foramen meningiomas are challenging because of their deep, neurovascularly crowded location and multicompartment extension; hyperostosis and rigid dural attachment further narrow the corridor and increase the risk of lower cranial nerve morbidity, causing dysphagia and airway complications that may rarely require tracheostomy. This study aimed to describe a contemporary function-first workflow integrating compartment-based anatomy, venous sinus status, preoperative embolization, and continuous vagus nerve monitoring and its relation to clinically actionable recovery endpoints. METHODS: The authors retrospectively reviewed 26 consecutive patients who underwent primary surgery for jugular foramen meningiomas (2014-2025). Tumors were classified as intradural + intrajugular (IJ) or intradural + intrajugular + extracranial extension (IJE). Retrosigmoid, suprajugular, or transjugular approaches were selected by tumor extension and sigmoid-jugular venous status. Selective embolization and continuous vagus nerve monitoring were used when feasible. Outcomes included extubation timing, time to oral intake, 1-year swallowing/voice severity, extent of resection, and salvage stereotactic radiosurgery (SRS) for progression/regrowth. RESULTS: Twenty tumors were IJ and 6 were IJE. Selective embolization was performed in 16 patients (62%) without complications. Continuous vagus nerve monitoring was implemented in 16 patients (62%); lower preservation rates showed an exploratory association with worse 1-year swallowing. All patients were extubated immediately after surgery. Oral intake began by postoperative day ≤ 7 in 20 patients (77%); only 1 required > 14 days before resuming oral intake. At 1 year, swallowing and hoarseness remained worse in 54% and 46% of patients, respectively, but almost all cases were mild; the same patient had moderate dysphagia/hoarseness, and none required tracheostomy, gastrostomy, long-term tube feeding, or phonosurgery. Simpson grade IV comprised 69% of cases but predominantly reflected intrajugular/extracranial residual rather than persistent intradural disease. No patient without preoperative facial nerve palsy developed new palsy; serviceable hearing was preserved in 70%, and 38% with preoperative nonserviceable hearing improved to serviceable hearing. During a median 55.6-month follow-up, 3 patients (12%) underwent salvage SRS for regrowth; none required reoperation. CONCLUSIONS: A function-first workflow guided by anatomical compartment extension and intraoperative monitoring can support rapid recovery and durable functional independence in jugular foramen meningiomas. The IJE phenotype identifies a higher-risk subgroup for delayed oral intake and postoperative subjective dysphagia/hoarseness, while continuous vagus nerve monitoring may provide actionable insights to calibrate surgical aggressiveness and support function-prioritized acceptance of intrajugular/extracranial residual with close surveillance and salvage SRS when needed.

Humans

Fluorescence mapping of mitochondrial redox changes in heart and brain.

Fluorescence techniques may be utilized to map changes in the distribution of mitochondrial redox states in heart and brain during ischemic or hypoxic stress. The basis of these techniques is the intrinsic fluorescence of reduced NADH and oxidized flavoprotein in mitochondria which respond to changes in critical oxygen supply. Ischemic areas in rabbit hearts induced by coronary ligation were detected and mapped based on the increase in NADH fluorescence in the ischemic zone. The width of the jeopardized normoxic tissue surrounding the ischemic area (less than 50--350 mu) was measured by combination of fluorescein angiography and NADH fluorescence. Areas of increased NADH fluorescence in gerbil brains after carotid artery ligation or induction of spreading depression were mapped in a similar manner. Intraoperative monitoring of flavoprotein fluorescence from human cerebral cortex after superficial temporal artery middle cerebral artery (STA-MCA) anastomoses demonstrated increased rates of cortical oxidative metabolism after the surgical procedures.

Animals

Recurrent laryngeal nerve localization using a microlaryngeal electrode.

Damage to the recurrent laryngeal nerve is a frequently seen complication in head and neck surgery. A system for intraoperative monitoring of the recurrent laryngeal nerve is presented. The key to this system lies in the use of a microlaryngeal electrode and inserter. Application of this system to various situations is described.

Electric Stimulation

The use and preliminary results of the Troutman surgical keratometer in cataract and corneal surgery.

The Troutman microsurgical keratometer has been shown to be useful in monitoring intraoperative procedures, and it has been demonstrated in the case of cataract and keratoplasty to have a significant influence on the control of operatively induced astigmatism. It is applicable to any surgical procedure which has the potential of altering permanently and unpredictably the corneal curvatures. Intraoperative keratometry has clearly demonstrated some inadequacies of our current cataract and keratoplasty techniques. It is now being used to guide our efforts toward a more rational control of the vexing problem of astigmatism.

Astigmatism

Automated measurement and frequency analysis of the pneumocardiogram.

The flow pneumocardiogram (PnCG), ie, measurement of cardiogenic gas movement in and out of the lung during apnea, was transduced by an in-line, high-gain pneumotachograph. A portion of the differentiated PnCG, the dPn/dt IJ wave, has been shown previously to correlate closely with left ventricular function. A simple analog device was designed and tested to measure the dPn/dt IJ amplitude on a practical beat-to-beat basis. Frequency-power spectral analysis showed the PnCG to be a low frequency phenomenon with the systolic component in the 9-to-10-Hz range. Appropriate band-pass filtering of the PnCG and its applicability as an intraoperative monitoring device are presented.

Analog-Digital Conversion