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We report three patients with thyrotoxicosis due to solitary autonomously functioning thyroid nodules, which at surgery were found to contain papillary carcinoma. Despite the rarity of this concurrence we suggest that it may be useful to employ fine-needle aspiration cytology in the evaluation of the solitary autonomously functioning thyroid nodules.
Effects of midazolam on the cardiac autonomic nervous system were studied by power spectral analysis of electrocardiographic R-R intervals in patients undergoing elective lower abdominal surgery under spinal anaesthesia. Patients were randomly assigned into two groups: 10 patients in group A received spinal anaesthesia only and 10 in group S received spinal anaesthesia and midazolam of 0.05 mg/kg when surgery started. In the frequency domain power spectra, low (Lo; 0.04-0.15 Hz) and high (Hi; 0.15-0.40 Hz) frequency components were integrated to ascertain sympathetic and parasympathetic activity, respectively. There was no intergroup difference in starting time of surgery, ventilatory frequency, arterial pressure, heart rate, mean and variance of R-R interval, and cephalad level of analgesia. In spectral component, Lo decreased (P < 0.05) and Hi/Lo ratio increased (P < 0.05) relative to their baselines in group S. These were also different from group A (P < 0.05). We concluded that intravenous midazolam depressed sympathetic activity to produce a vagotonic cardiac autonomic nervous system under spinal anaesthesia.
Thirty-eight consenting subjects scheduled for elective ophthalmologic surgery were classified as nondiabetics (n = 21) or diabetics (n = 17) and were tested preoperatively for autonomic dysfunction. The autonomic tests consisted of respiratory sinus arrhythmia and heart rate responses to the Valsalva maneuver to test cardiac vagal function and diastolic blood pressure responses to head-up tilt and cold pressor test to assess sympathetic efferent integrity. At a separate time, anesthesia was established with fentanyl (2 micrograms/kg), sodium thiopental (3-5 mg/kg), and vecuronium (0.1 mg/kg), and maintained with isoflurane, oxygen, and nitrous oxide. An anesthesiologist, blinded to the autonomic test results, recorded perioperative blood pressure and heart rate. The autonomic test results revealed significant autonomic dysfunction among the diabetics. Heart rate and blood pressure declined to a greater degree (P less than 0.05) during induction of anesthesia in diabetics compared with controls and there was less of an increase in these same parameters following tracheal intubation in diabetic patients. Thirty-five percent of diabetics required intraoperative vasopressors compared with only 5% of control patients (P less than 0.05). A major finding was that the diabetics who required intraoperative blood pressure support had significantly greater impairment of autonomic test results compared with those diabetics who did not need vasopressors. Diabetics are at increased risk for cardiovascular lability during anesthesia and preoperative screening of diabetics with simple noninvasive autonomic tests may be useful in identifying those at high risk for perioperative cardiovascular instability.
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Research indicates hysterectomy surgery may adversely affect the pelvic autonomic nerves and autonomic mechanisms are integral to the sexual arousal response in women. This study explored the possibility that women who undergo hysterectomy may experience an impaired vasocongestive response to erotic stimulation. Thirty-two women with a history of benign uterine fibroids who had ( n = 15) or had not ( n = 17) undergone hysterectomy participated in two experimental sessions in which self-report and physiological (vaginal pulse amplitude; VPA) sexual responses were recorded during an erotic film presentation. In one of the sessions, the women exercised on a treadmill for 20 min prior to viewing the erotic films as a means inducing autonomic arousal. Exercise significantly increased VPA but not subjective sexual responses in both groups of women. VPA responses were marginally higher among the fibroid than hysterectomy group in the no-exercise condition. The hypothesis that physiological sexual arousal may be impaired with hysterectomy surgery was only partially supported.
The state of anaesthesia is one of unconsciousness, lack of awareness, amnesia and reflex suppression to noxious stimuli. The depth of anaesthesia is generally considered adequate if the patient neither moves in response to surgical stimulus nor shows any signs of autonomic reflexes. Anaesthesia is generally considered inadequate if the patient has recall after surgery!
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AIMS: To examine the long-term outlook for patients with intractable vomiting from diabetic gastroparesis who underwent major gastric surgery. METHODS: Of 18 patients with problems from vomiting referred to the King's Diabetes Centre during the years 1994-2000, seven were considered to suffer irreversible symptoms not alleviated by protracted periods of medical treatment. They were all Type 1 Caucasian diabetic women, mean age 32 years (range 28-37 years) with multiple symptoms of severe autonomic neuropathy. They underwent major gastric surgery comprising 70% gastric resection including pylorus and antrum, with a 60-cm Roux-en-Y loop of jejunum to prevent reflux gastritis. RESULTS: The vomiting was relieved in six of the seven patients almost immediately after surgery and during review up to more than 6 years post-operatively. There have been no serious relapses, resulting in considerable improvement in quality of life. Unfortunately, three of the patients developed renal failure, two of them needing renal support treatments 2 and 3 years after successful gastrectomy. One patient died suddenly 5 months after successful surgery and one 3 months after starting dialysis. CONCLUSIONS: Major gastric surgery can, after careful patient selection, effectively relieve distressing vomiting from severe gastroparesis and give a greatly improved quality of life to a small group of seriously disadvantaged patients where risk of subsequent renal failure is high and where life expectancy is poor.
BACKGROUND: This is part II of a 2-part series examining artificial intelligence in colorectal surgery. Part I established foundational concepts and clinical applications. Implementation, however, requires understanding research methodologies, available resources, and the specific challenges currently limiting widespread adoption. These topics are the focus of part II. OBJECTIVE: To examine artificial intelligence's transformation of surgical research, provide practical implementation resources, address adoption challenges, and explore future directions in colorectal surgery. METHODS: Comprehensive literature review focusing on artificial intelligence research methodology, implementation barriers, educational resources, and emerging technologies relevant to colorectal surgeons. RESULTS: Artificial intelligence streamlines clinical trial design through predictive modeling and natural language processing, reducing enrollment challenges that contribute to failed or inadequate trial accrual. Machine learning enables heterogeneity analysis within clinical trials, identifying treatment-responsive subgroups. Foundation models unlock analysis of unstructured electronic health record data at scale. Professional societies and universities offer specialized artificial intelligence education programs, with open-access data sets facilitating research participation. However, implementation faces multifaceted challenges: technical infrastructure demands, with real-time processing requiring dedicated graphics processing unit clusters; regulatory frameworks struggling with continuously evolving algorithms; undefined liability distribution for artificial intelligence-assisted decisions; algorithmic bias risking health care disparities; and the "black box" problem limiting clinical trust. Economic barriers include substantial initial costs without clear reimbursement pathways. Future directions include multimodal artificial intelligence integrating imaging, genomics, and histopathology; cognitive robotic systems with real-time decision support; digital twin technology for patient-specific surgical simulation; and global surgical artificial intelligence networks enabling distributed learning across institutions. CONCLUSIONS: Although artificial intelligence offers transformative potential for colorectal surgery research and practice, successful implementation requires addressing technical, regulatory, ethical, and economic challenges. The surgeon's evolving role demands both traditional expertise and computational fluency. Future advances in multimodal integration, autonomous systems, and global collaboration will fundamentally reshape surgical practice but will require thoughtful implementation prioritizing patient benefit and clinical value.
OBJECTIVE: Heart rate variability (HRV) is the most frequently used noninvasive diagnostic method in the assessment of cardiac autonomic control. The clinical relevance of HRV, especially nonlinear HRV in CPB patients has not been well studied. Short brief myocardial ischemia has been reported to influence HRV. We therefore hypothesis that the protective mechanism of ischemic preconditioning (IP) may involve in cardiac autonomic regulation. METHODS: Eighty-six CABG patients were randomized into a control and an IP group. The IP patients received two periods of 2-min ischemia followed by 3-min reperfusion by aortic cross-clamped. Holter data were collected in 86 CABG patients before and after surgery. Arrhythmias, linear and nonlinear HRV measures were analyzed. RESULTS: All time and frequency domain HRV variables as well as nonlinear indexes of HRV, the short-term (4-11 beats) scaling exponent alpha1, were suppressed significantly after surgery in both study groups. The lower pre- and postoperative exponent alpha1 predict the higher incidence of postoperative AF and worse postoperative outcome. The suppressed exponent alpha1 was attenuated in the IP group as compared to controls (P = 0.008). No other differences were observed in the changes in linear HRV measures between the groups. IP significantly reduced the incidence of postoperative arrhythmias and improved postoperative outcome. CONCLUSIONS: The present findings show that cardiac autonomic regulation is impaired after CABG. Nonlinear HRV exponent alpha1 is a more sensitive measure to predict the postoperative outcome in CABG patients. IP alleviates the extreme autonomic reactions after surgery, suggesting that cardiac autonomic regulation is involved in the IP protective mechanism.
Some 20-40% of diabetics suffer from an autonomic neuropathy. This complication of diabetes mellitus impairs the regulation and the reflexes of the cardiovascular system. This study compares the cardiovascular characteristics of diabetics and nondiabetic control patients. METHODS. 21 patients (11 diabetics, 10 nondiabetics) undergoing ophthalmic surgery were investigated. They were tested preoperatively for autonomic cardiovascular dysfunction by application of four established tests. These were: heart rate responses to the Valsalva maneuver, deep breathing and standing up (30/15 test) and the Schellong test. The anaesthesia was induced with fentanyl (0.1 mg), etomidate (2.5 mg/kg) and succinyl choline (1.5 mg) and maintained with oxygen/nitrous oxide (1.4:3 l/min) and isoflurane (0.2-0.8 vol%). Blood pressure and heart rate were automatically measured every minute during induction of anaesthesia and every 3 min during anaesthesia. Additionally the heart rate response to 0.5 mg atropine i.v. was evaluated. RESULTS. The autonomic function tests revealed pathologic reactions in all diabetics (two early, six definitive, three severe) and none in controls. Remarkable cardiovascular events occurred exclusively in the diabetic group, especially during induction of anaesthesia. The systolic blood pressure (SAP) increased in diabetics from a preinduction value of 150 mmHg (median, range 105-205 mmHg) to a maximum of 200 mmHg (160-250 mmHg) after intubation, in controls from 130 (100-150 mmHg) to 170 (110-190 mmHg). Following this peak, SAP fell in diabetics to 120 mmHg (80-160 mmHg), in controls to 110 (100-140 mmHg). Two diabetics had to be treated because of an SAP exceeding 220 mmHg, two other diabetics because of an SAP below 80 mmHg. After atropine administration the heart rate of diabetics showed a median increase of 15% (range 0-40%). In four diabetics, however, the increase was less than 10%. In control patients the increase was 50% (40-80%). All patients with severe cardiovascular reactions during induction of anaesthesia and with heart rate elevation following atropine of less than 10% had a definite or severe neuropathy of the autonomic nervous system revealed by the tests. DISCUSSION. In the only slightly stressful ophthalmic surgery, remarkable events were noted particularly during the induction of anaesthesia. The critical decreases and increases of SAP might be related to the autonomic dysfunction, because of the hypersensitivity of a partly damaged autonomic nervous system or its impaired function. This led to a loss of heart rate variation and adequate blood vessel tone. The severe cardiovascular reactions always went along with clearly pathologic findings in the tests performed. Normal test results in diabetics implied normal cardiovascular reactions, as could be observed in nondiabetics. CONCLUSION. Abnormal cardiovascular reactions in diabetics must be kept in mind. The simple tests specified here can identify such predisposed patients.
Primary hyperaldosteronism (adrenal adenoma and idiopathic hyperplasia) is a disorder with hypertension, hypokalemia, elevated serum aldosterone and suppressed plasma renin activity. Hyperplasia is managed medically whereas adenomas are treated surgically. Selective adrenal venous catheterization and aldosterone measurement is a useful tool in making the distinction in 95% of cases. We report a case of bilateral idiopathic hyperplasia of the adrenal glands adequately treated with medications for 6 years followed by worsening. Selective catheterization was consistent with a right sided adenoma. Surgical removal of the right adrenal gland alleviated her symptoms. Pathological examination showed focal nodular hyperplasia. We propose that in the course of the disease the focal hyperplastic nodule became autonomous and behaved like an adenoma. Monitoring of patients with adrenal hyperplasia for recurrence of symptoms is prudent as surgery is beneficial in patients who develop an autonomous nodule.
Sinus node dysfunction is a recognized problem following surgery for congenital heart disease. Seven postoperative patients with sinus node dysfunction (5 Mustard, 1 tetralogy of Fallot, 1 Fontan) underwent electrophysiology study of sinus node function during combined autonomic blockade (CAB) utilizing propranolol 0.2 mg/kg i.v. and atropine 0.04 mg/kg i.v. to evaluate intrinsic sinus node function isolated from autonomic control. During CAB, intrinsic heart rate, intrinsic corrected sinus node recovery time, and intrinsic sinoatrial recovery time were measured. These results were compared with age-matched normal intrinsic data from our lab [normal (n = 7, mean age 9 years) IHR 128 +/- 24, intrinsic corrected sinus node recovery time 135 +/- 40 ms, intrinsic sinoatrial conduction time 86 +/- 19 ms]. Among postoperative Mustard patients (n = 5, mean age 13 years, mean years postoperative 11) 2 of 5 had clearly abnormal intrinsic sinus node function with nonsinus rhythm during CAB; 3 of 5 had sinus rhythm during CAB with normal or mildly abnormal intrinsic sinus node function. The postoperative case of tetralogy of Fallot (age 20 years, postoperative 14 years) had mildly abnormal intrinsic sinus node electrophysiology study. The postoperative case of Fontan (age 16 years, postoperative 1.5 years) had sinus rhythm at rest but left atrial rhythm during CAB. Different aspects of sinus node dysfunction may be expressed during resting electrophysiology study vs. electrophysiology study utilizing CAB. The pathophysiology of sinus node dysfunction among postoperative pediatric patients is not homogeneous with regard to the contribution of intrinsic sinus node dysfunction. In those patients with normal or mildly abnormal intrinsic sinus node function, an important pathophysiologic influence of the autonomic nervous system is implicated.
Traction of the mesentery is known to induce strong autonomic reactions in patients undergoing abdominal surgery. An experimental model using this stimulus in anaesthetized rats has been developed, which allows the comparison of noxious mechanical and chemical stimulation of the mesentery. Graded traction on a bundle of jejunal vessels with 2-30 g led to reflex changes in blood pressure and intragastric pressure, the size of which correlated with the strength of the stimulus. Comparable responses were elicited by clamping the same vessels either at their distal or proximal end or by applying 100 microl 0.6% acetic acid or 0. microM bradykinin. These reflexes are fairly insensitive towards impairment of the autonomic system. Only the combination of phentolamine and propranolol reduced the cardiovascular responses to all stimuli but at the same time, significantly lowered basal blood pressure. The adrenoceptor antagonists affected the gastric response to acid only. Atropine on its own was ineffective. Administered together with the combination of adrenoceptor blockers it had no further influence on the cardiovascular reflexes but significantly reduced the gastric responses to stretch, proximal clamping and acid. Acute desensitization of small diameter afferents with capsaicin almost abolished the reflex responses to acid. The cardiovascular, but not the gastric, response to traction was reduced by capsaicin. Morphine led to dose-dependent reductions of the reflex responses in a naloxone-reversible manner, whereas indomethacin was inactive. The bradykinin B2-antagonist icatibant abolished the reflex in response to the application of bradykinin but not to acid or traction. It is concluded that the measurement of the cardiovascular and gastric responses of anaesthetized rats to traction on the mesentery is a suitable method to investigate acute visceral nociception. Chemical stimuli to the mesentery are transmitted by capsaicin-sensitive afferents, but there is a dichotomy regarding capsaicin's influence on visceral mechanonociception. Opioid mechanisms are always involved, whereas prostaglandins or bradykinin have no role in the reflexes evoked by acid or traction. Intact alpha- or beta-adrenergic (as tested with unselective receptor antagonists) or muscarinic mechanisms are required for the reaction of the end organs in the reflex but they have no role in the afferent or central processing.
Follow-up of 102 patients operated upon for autonomous thyroid nodules is reported. Retrospective study of operative findings and aftermath of surgery clearly demonstrates that the patho-physiological concept of autonomous nodule does not snugly fit practical problems experienced with the management of such patients. The autonomous nodule can be a malignancy. Ipsilateral thyroid lobectomy seems more suitable than nodulectomy. Gross appearance of the thyroid remnant makes sometimes post-operative hormonotherapy unexpectedly advisable. From a theoretical point of view, post-operative thyroid scan, TSH assay and TRH test are mandatory, to assess recovery.
OBJECTIVE AND HYPOTHESIS: Posttraumatic clear rhinorrhea should result in immediate concern for a suspected cerebrospinal fluid (CSF) fistula in patients with skull base injuries, including surgical trauma. However, in addition to CSF rhinorrhea, the differential diagnosis may also include postinjury autonomic dysfunction. Pseudo-cerebrospinal fluid rhinorrhea (PCSFR) is a term used to describe rhinorrhea resulting from injury to preganglionic parasympathetic fibers supplying the sphenopalatine ganglion. This ganglion plays a critical role in this pathway secondary to its anatomic course and physiologic function. Differentiating between PCSFR and true CSF rhinorrhea can be a diagnostic challenge and may result in unnecessary and costly invasive testing and treatment. CASE STUDY: The authors present an illustrative case of noniatrogenic posttraumatic PCSFR in a previously healthy patient who experienced a head injury in a horseback riding accident. DISCUSSION: Features of PCSFR include a history of skull base surgery or trauma with involvement of autonomic structures in this region, rhinorrhea within months or years after injury, decreased lacrimation on the involved side, absence of clinical signs of meningitis, and a negative beta2-transferrin test result. Management of PCSFR is aimed at restoring the normal autonomic homeostasis in the nasal cavity. Treatment options include topical medicines such as anticholinergics and the various surgical procedures aimed at disruption of parasympathetic preganglionic fibers proximal to or at the sphenopalatine ganglion. CONCLUSION: This case and its diagnosis and management provide an additional mechanism of PCSFR, a clinical entity that must be considered in the evaluation of all patients with previous skull base trauma.
OBJECTIVE: To evaluate the role of the autonomic nervous system for the development of atrial fibrillation (AF) after coronary artery bypass surgery. DESIGN: Eighty patients without a previous history of AF were included. The sympathetic and parasympathetic activity were evaluated by the analysis of heart rate variability (HRV) in the frequency domain from 24-h Holter recordings and by measuring neuropeptides (neuropeptide Y, chromogranin A, chromogranin B, and pancreatic polypeptide (PP)) and catecholamines, obtained pre- and postoperatively. RESULTS: Preoperatively, patients (36.3%) developing AF postoperatively showed a statistically significant less circadian variation in the HRV variables, the high-frequency (HF) component (p = 0.013) and the low-frequency (LF)/HF ratio (p = 0.007), than patients remaining in sinus rhythm. The HF component and PP. both reflecting parasympathetic activity, and all other variables in the frequency domain, decreased significantly after surgery in both patient groups (p < 0.0001). Although catecholamines increased significantly postoperatively in both patient groups, neither catecholamines nor neuropeptides expressing sympathetic activity, differed between the two groups. PP was, however, significantly higher in patients with postoperative AF than in those with sinus rhythm postoperatively on day 1. CONCLUSION: The diminished circadian variation in HRV before surgery and the indirect signs of a higher parasympathetic activity in patients developing postoperative AF compared with patients remaining in sinus rhythm, may indicate a propensity for AF.