Nordic consensus on treatment of undescended testes.

AIM: To reach consensus among specialists from the Nordic countries on the present state-of-the-art in treatment of undescended testicles. METHODS: A group of specialists in testicular physiology, paediatric surgery/urology, endocrinology, andrology, pathology and anaesthesiology from all the Nordic countries met for two days. Before the meeting, reviews of the literature had been prepared by the participants. RECOMMENDATIONS: The group came to the following unanimous conclusions: (1) In general, hormonal treatment is not recommended, considering the poor immediate results and the possible long term adverse effects on spermatogenesis. Thus, surgery is to be preferred. (2) Orchiopexy should be done between 6 and 12 months of age, or upon diagnosis, if that occurs later. (3) Orchiopexy before age one year should only be done at centres with both paediatric surgeons/urologists and paediatric anaesthesiologists. (4) If a testis is found to be undescended at any age after 6 months, the patient should be referred for surgery--to paediatric rather than general surgeons/urologists if the boy is less than one year old or if he has bilateral or non-palpable testes, or if he has got relapse of cryptorchidism.

Surgical treatment of undescended testes.

UNLABELLED: The mainstay of therapy for undescended testes is operative treatment within the first years of life in order to avoid ongoing testicular degenerative changes. The surgical therapy for the palpable undescended testis is orchiopexy and when the testis is non-palpable, a supplementary laparoscopic approach. Success of orchiopexy for inguinal testes has been >95% and for abdominal testes >85-90% in most series. CONCLUSION: Operation within the first year of life is a safe therapy for undescended testes.

Blood-borne factors possibly associated with post-operative nausea and vomiting: an explorative study in women after breast cancer surgery.

BACKGROUND: The pathophysiology behind post-operative nausea and vomiting (PONV) is still not fully understood, especially with respect to gender. According to PONV risk scores, female gender is the strongest predictor for PONV. The risk for PONV after general anaesthesia for breast cancer surgery is 50-80%. The aim of the present explorative study was to identify blood-borne factors that might be associated with the development of PONV in women undergoing breast cancer surgery as a basis for further studies. METHODS: Fifty patients were enrolled prospectively in the study. A standardized sevoflurane-based anaesthetic was used. Blood samples for the analysis of vasopressin, gastrin, cholecystokinin, epinephrine, norepinephrine, dopamine, serotonin, platelet count and blood glucose were taken at six pre-determined time points peri-operatively, and PONV was assessed during 24 h. RESULTS: PONV was found in 27 of 47 patients completing the study. Patients with PONV had a larger variability of the platelet count (P = 0.001), a reduced platelet count on the first post-operative day (P = 0.02) and a less pronounced relationship between the platelet count and whole blood serotonin (P = 0.004) compared with non-PONV patients. A lack of a decrease in epinephrine levels in response to the induction of anaesthesia (P = 0.03) and increased levels of vasopressin (P < 0.001), epinephrine (P = 0.005) and blood glucose (P = 0.004) were observed in the early post-operative period in PONV patients. CONCLUSION: Three different platelet-associated factors and an altered epinephrine pattern were found to be associated with the occurrence of PONV after breast cancer surgery.

Atracurium and vecuronium block nicotine-induced carotid body chemoreceptor responses.

BACKGROUND: Vecuronium depresses carotid body chemosensitivity during hypoxia. We hypothesized that this is caused by inhibition of cholinergic transmission of the carotid body. METHODS: The carotid body with its sinus nerve was removed en bloc from thiopentone-anaesthetized adult male New Zealand rabbits and perfused in vitro with modified Tyrodes buffer solution at constant perfusion pressure, temperature, a buffer pH of 7.4 and normocapnia. Chemoreceptor discharge and spike frequencies (fx) were recorded from the whole sinus nerve after administration of 500 microg nicotine, given as duplicated controls and thereafter following 30 min perfusion of equipotent concentrations of atracurium (28.1 microM) or vecuronium(10 microM), after 30 min of neostigmine perfusion (9.2 microM) and finally after 30 min wash-out with buffer solution only. A short-lasting hypoxic test was performed before and at the end of the experimental period to confirm the responsiveness and validity of the preparation. RESULTS: Atracurium (n = 7) and vecuronium (n = 6) reduced chemoreceptor responses to nicotine by 70 +/- 30% and 66 +/- 19% (SEM) (P<0.05). Chemoreceptor discharges showed full recovery after neostigmine in the atracurium group and partial recovery in the vecuronium group (P<0.05). Finally, after wash-out the chemoreceptor responses to nicotine had fully recovered in both groups. CONCLUSION: Atracurium and vecuronium in equipotent concentrations block nicotine-induced chemoreceptor responses of the carotid body.

Prone position improves gas exchange--but how?

* Mechanically ventilated patients with severe acute lung insufficiencies dramatically improve their gas exchange when treated in the prone position. * ventilation heterogeneity is greater in the supine then in the prone position during CMV. * the dominant dorsal Q while supine is not turned into a dominant ventral Q in the prone position. * in the presence of an abdominal distension, the prone position more clearly improves gas exchange than at normal abdominal pressures. * CPAP enhances the dominant dorsal lung perfusion while supine. In the prone position lung perfusion is more uniform. * V/Q matching is improved in the prone position during CMV.

Evaluation of harvested and normal patellar tendons: a reliability analyses of magnetic resonance imaging and ultrasonography.

This study compared the reliability (interchangeability) of magnetic resonance imaging (MRI) and ultrasonography (US) examinations of the patellar tendon after using central third patellar tendon autografts during anterior cruciate ligament reconstruction. Nineteen consecutive patients (7 women, 12 men) underwent bilateral MRI and US of the patellar tendons 27 (24-29) months after anterior cruciate ligament reconstruction using ipsilateral central third patellar tendon autografts. Two experienced radiologists blinded to one another evaluated the examinations. Measurements of the length of the noninjured patellar tendon showed the greatest reliability between MRI and US, with no systematic difference (P=0.48), a small mean difference (-0.1 mm), and an interclass correlation coefficient of 0.74. The measurements of the thickness and width of the noninjured side were also judged as reliable. However, on the injured side a lower reliability was found between MRI and US. We conclude that MRI and US are reliable (interchangeable) methods only for evaluating noninjured patellar tendons.

Effects of neuroactive substances on the morphine-induced respiratory depression; an in vitro study.

Effects of different neuroactive substances on morphine-induced respiratory depression were studied in medullary respiration-related structures using in vitro brainstem-spinal cord preparation from 1 to 4-day-old rats. Application of morphine (10 microM) reduced respiratory rhythm (fR) as measured by C4 ventral root activity. The depressant effects of morphine were reversed by acetylcholine (10 microM), substance P (50 nM), thyrotropin releasing hormone (TRH) (100 nM) and forskolin (10 microM). The adenosine receptor antagonist, theophylline (100 microM), the dopamine receptors antagonist, haloperidol (10 microM), the cyclooxygenase inhibitor, indomethacin (10 microM) and the phospholipase A(2) inhibitor, quinacrine (10 microM) had no effect on morphine-induced respiratory depression.

A radiographic and histologic evaluation of the patellar tendon after harvesting its central third.

Nineteen consecutive patients undergoing anterior cruciate ligament reconstruction using the central third of the ipsilateral patellar tendon were included in the study. Serial magnetic resonance images revealed that the donor-site gap in the tendon decreased with time (mean follow-up, 26 months). The thickness was significantly increased compared with the intact contralateral patellar tendon, regardless of when the magnetic resonance imaging was performed. Ultrasonography showed the same findings at a mean follow-up of 26 months. Histologic evaluation of the repair tissue in the central part of the tendon, as well as the tissue in the peripheral part of the patellar tendon at the donor site, revealed a significant increase in cellularity and vascularity as compared with normal control tendons. Thus, 2 years after the harvesting procedure, the patellar tendon displayed significant radiographic and histologic abnormalities. On the basis of these findings, reharvest of the patellar tendon, at least up to 2 years after primary harvest, cannot be recommended.

Amino acid-induced thermogenesis reduces hypothermia during anesthesia and shortens hospital stay.

UNLABELLED: Amino acid infusion during general anesthesia induces thermogenesis and prevents postoperative hypothermia and shivering. We propose that amino acid prevention of hypothermia during anesthesia shortens the hospital stay. Core temperatures and pulmonary oxygen uptake were measured in 45 patients, receiving an IV amino acid mixture, 126 mL/h, before and/or during isoflurane anesthesia and 30 control patients receiving acetated Ringer's solution. At awakening, mean core temperature was 36.5 degrees+/-0.1 degrees C in the amino acid group and 35.7 degrees+/-0.1 degrees C (P < 0.001) in the controls. Energy expenditure increased by 54%+/-9% from baseline in amino acid patients in whom shivering was uncommon, but only by 5%+/-4% (P < 0.001) in control patients, of whom the majority developed postoperative shivering. The estimated difference in hospital stay between the two groups was 2.7 days (CI 95%: 1.3-4.0). Multiple regression analysis showed that the variables best predicting hospitalization were duration of surgery, amino acid treatment, and awakening temperatures. Duration of surgery was similar in the two groups and core temperatures at awakening were a result of amino acid infusion, which indicates that amino acid infusion during anesthesia and surgery was the most important factor for the shorter hospitalization. IMPLICATIONS: Amino acid infusion during general anesthesia induces thermogenesis and prevents postoperative hypothermia and shivering. Multiple regression analysis indicated that this resulted in a shorter hospital stay.

Magnetic resonance imaging of the patellar tendon after harvesting its central third: a comparison between traditional and subcutaneous harvesting techniques.

The aim of this study was to compare the 2-year results after anterior cruciate ligament reconstruction using patellar tendon autografts harvested through a paratenon-splitting, traditional technique (group A) with the results of a subcutaneous technique aiming at protecting the infrapatellar nerves and the paratenon (group B). Special emphasis was placed on evaluating the donor site. Magnetic resonance imaging (MRI) of the patellar tendon was performed to evaluate the reconstitution after harvesting its central third. Examinations of knee-walking ability and assessments of anterior knee sensitivity were made in order to evaluate donor-site discomfort and the function of infrapatellar nerves. Seventy-two consecutive patients were included in the study; group A comprised 35 patients and group B, 37 patients. At the 2-year follow-up, the Tegner activity level, the Lysholm score, and the IKDC evaluation system showed no significant differences between groups A and B. The median loss of normal anterior knee sensitivity was 16 cm2 (range, 0 to 200 cm2) in group A and 0 cm2 (range, 0 to 285 cm2) in group B (P = .20). In group A 20% of the patients and in group B 58% had normal sensitivity (P < .01). MRI showed that the donor-site gap (area corresponding to non-tendinous-like tissue signal) was 5 mm (range, 0 to 9 mm) in group A and 2 mm (range, 0 to 5 mm) in group B (P < .0001). At 2-year follow-up, the subcutaneous graft-harvesting technique resulted in less disturbance of anterior knee sensitivity and a smaller donor-site gap than the traditional technique.

Ventilatory responses to acute and sustained hypoxia during sevoflurane anesthesia in women.

UNLABELLED: We investigated the isocapnic hypoxic (i.e., pulse oximetry monitored arterial saturations 70%-75%) ventilatory response (HVR) for 20 min in the awake state and during sevoflurane anesthesia at an end-tidal concentration of 1.6% in eight healthy (ASA physical status I) women. Our aims were to determine if a prolonged isocapnic hypoxic period during sevoflurane anesthesia showed a biphasic response pattern (i.e., an initial acute HVR followed by a decline to a lowered sustained HVR) and, if so, to quantify to what extent the acute and sustained HVRs were depressed by anesthesia. The study was conducted before laparoscopic gynecological surgery. Pneumotachography and in-line infrared capnography were used. The pattern of awake biphasic HVR was maintained during anesthesia but was depressed during both the acute and the sustained phases by 60% and 70%, respectively. Further, HVR during anesthesia was accomplished by an increase in respiratory rate, in contrast to an increase in tidal volume in the awake state. In conclusion, sevoflurane anesthesia at 1.6% depresses HVR in women, but the biphasic response is maintained. IMPLICATIONS: Acute and sustained hypoxic ventilatory responses were investigated in eight women before and during sevoflurane anesthesia. A biphasic ventilatory response was persistent but blunted during anesthesia.

Serial magnetic resonance imaging of the donor site after harvesting the central third of the patellar tendon. A prospective study of 37 patients after arthroscopic anterior cruciate ligament reconstruction.

The aim of this prospective study was to follow the development of repair tissue in the donor-site area using serial magnetic resonance imaging (MRI) evaluation and to assess whether the MRI findings were correlated with donor-site morbidity. Thirty-seven consecutive patients with unilateral anterior cruciate ligament injuries undergoing elective reconstruction of the ligament were included in the study. They were aged 27 (range 14-50) years. The graft was harvested through two 25-mm vertical incisions with the aim of protecting the infrapatellar nerve and sparing the paratenon. The tendon defect was left open. The patients underwent MRI evaluation at 6 weeks, 6 months and 27 months postoperatively. A final clinical follow-up was made 25 (range 23-29) months postoperatively. MRI demonstrated that the donor-site gap, i.e. the area corresponding to a pathological non-tendinous-like tissue signal, was 9 (range 4-18) mm at 6 weeks, 5 (range 2-14) mm at 6 months and 2 (range 0-5) mm at 27 months. The size of the donor-site gap had significantly decreased at 6 months compared with 6 weeks (P = 0.0001), as well as at 27 months compared with 6 months (P = 0.0001). We conclude that the patellar tendon at the donor site healed gradually, as expressed by a decrease in the area of non-tendinous-like tissue signal on the serial MRI evaluations.

Amino acid-induced thermogenesis to prevent hypothermia during anesthesia is not associated with increased stress response.

UNLABELLED: Intraoperative infusion of amino acids stimulates oxygen uptake with a resulting increase in heat production, especially during emergence from anesthesia. To determine whether the increased thermogenesis in response to amino acid infusion during and after anesthesia induces any additional stress in surgical patients, plasma catecholamines were measured. Fourteen patients aged 44+/-15 yr scheduled for gall bladder surgery during isoflurane anesthesia were studied. Seven patients received an IV amino acid infusion at the rate of 126 mL/h throughout anesthesia, and seven control subjects received equal volumes of nutrient-free saline. At five defined times during and after anesthesia, arterial adrenaline and noradrenaline concentrations were determined. Arterial blood pressure and heart rate were recorded simultaneously. There were considerable variations from baseline in levels of plasma adrenaline and noradrenaline, heart rate, and blood pressure during the study period, but there were no significant differences between the two groups at any time throughout anesthesia and surgery. In conclusion, the augmented thermogenic effect of amino acids during and at emergence from anesthesia is suggested to occur without imposing any additional stress in the surgical patient. IMPLICATIONS: Amino acid infusion during anesthesia has been demonstrated to markedly increase oxygen consumption and heat production. To determine whether this evokes any stress in the patients, we measured plasma catecholamines during anesthesia. We suggest that temperature preservation during anesthesia by an amino acid infusion occurs without additional sympathoadrenal activity.

Postoperative nitrogen excretion after amino acid-induced thermogenesis under anesthesia.

UNLABELLED: Amino acid infusions during general anesthesia induce thermogenesis and prevent postoperative hypothermia. The effects of increased heat production during anesthesia on postoperative nitrogen balance have not been examined. Therefore, we studied the effect of perioperative amino acid infusions on postoperative nitrogen excretion in 24 patients scheduled for hysterectomy. Seven volunteers not subjected to anesthesia or surgery were used as awake controls. During isoflurane anesthesia, 8 patients received acetated Ringer's solution, and 16 patients received an IV amino acid mixture, 240 kJ/h, before and during anesthesia. Rectal temperature and energy expenditure were measured. The urinary nitrogen content was calculated from urea, creatinine, and urate the day before surgery and for 4 days postoperatively. Diets were recorded. In anesthetized control patients, postoperative nitrogen excretion was less than preoperative levels. Those patients also experienced the largest decrease in core body temperature during anesthesia (1.7+/-0.1 degrees C). All had postoperative shivering. In the amino acid-treated patients, the temperature decrease during anesthesia was less pronounced (1.0+/-0.1 degrees C; P < 0.001) and postoperative shivering disappeared. In addition, the nitrogen excretion was unchanged postoperatively, perhaps indicating an increase in protein turnover known to generate heat. In conclusion, the increase in heat production induced by amino acids reduced hypothermia, abolished shivering, and attenuated/normalized the postoperative nitrogen saving that occurred in patients who did not receive amino acids. IMPLICATIONS: We compared nitrogen excretion before and after surgery in patients who received a saline or amino acid infusion during isoflurane anesthesia. The increase in heat production induced by amino acids reduced hypothermia, abolished shivering, and attenuated/normalized the postoperative nitrogen saving that occurred in patients who did not receive amino acids.

Ipsi- or contralateral patellar tendon graft in anterior cruciate ligament revision surgery. A comparison of two methods.

Twenty-four patients who underwent anterior cruciate ligament revision surgery were studied postoperatively (12 with reharvested ipsilateral patellar tendon grafts and 12 with contralateral patellar tendon grafts). For comparison purposes, 12 matched patients with primary anterior cruciate ligament reconstruction, who had been operated on using the same technique by the same surgeons, were chosen. The median time since the first reconstruction was 57 months (range, 15 to 132) in the ipsilateral tendon group and 54 months (range, 20 to 108) in the contralateral tendon group. Follow-up examination showed that there were no significant differences in total KT-1000 arthrometer side-to-side measurements between the groups, but the Lysholm score was higher for patients with contralateral tendon grafts than for patients with ipsilateral grafts. Only two patients with ipsilateral grafts were classified as having excellent or good results. Functional testing outcomes were similar for all groups, and magnetic resonance imaging screening showed no differences between the reharvest and primary harvest groups in terms of length, width, thickness, or donor site gap of the patellar tendon. However, there were two major complications in the group with revision surgery with the ipsilateral reharvested patellar tendon. Reharvesting the ipsilateral patellar tendon resulted in lower functional scores and a higher rate of complications than revision with the contralateral patellar tendon or primary anterior cruciate ligament reconstruction.

Ventilatory responses to acute and sustained hypoxia during isoflurane anesthesia.

UNLABELLED: In the awake state, isocapnic hypoxic ventilatory responses (HVRs) are biphasic, with an acute response within 5 min of hypoxic stimulation followed by a less pronounced sustained response. In this study, we investigated the influence of isoflurane anesthesia (end-tidal concentration 1.1 kPa) on acute and sustained isocapnic HVRs in eight healthy women at pulse oximetry arterial saturations of 75%-80%. The aims were to determine whether HVR (20 min of hypoxia) during anesthesia was biphasic and to quantify ventilatory responses. Pneumotachography and in-line infrared capnometry were used. A biphasic HVR was found both in awake and anesthetized patients. Of the subjects, six had decreased and two had increased acute and sustained isocapnic HVRs in the anesthetized, compared with the awake state, which resulted in an approximately 50% reduction in both acute and sustained HVRs. In addition, the ventilatory response pattern was altered by anesthesia. Awake HVR was accomplished by increased tidal volumes while respiratory rates were unchanged. The opposite occurred during anesthesia. The underlying mechanisms for this biological action of inhaled anesthetics remains to be elucidated. In conclusion, this study clearly demonstrates the persistence of hypoxic ventilatory sensitivity during clinical anesthesia. IMPLICATIONS: We studied the ventilatory effects of 20 min of breathing air with low oxygen content (hypoxic) in eight women, before and during anesthesia with inhaled isoflurane. We demonstrated a persistent but blunted hypoxic ventilatory response during clinical anesthesia.

Analysis of the cellular mechanism for halothane inhibition of brown adipose tissue thermogenesis.

In the present studies, halothane is demonstrated to have a general inhibitory effect on norepinephrine-induced cAMP accumulation, lipolysis and rate of oxygen consumption, but no obvious effect on the respiratory capacity of isolated mitochondria. Further studies are necessary to elucidate these effects of halothane on brown adipose tissue nonshivering thermogenesis. Such studies may contribute to the understanding of the molecular effects of volatile anesthetics.

Factors affecting donor-site morbidity after anterior cruciate ligament reconstruction using bone-patellar tendon-bone autografts.

The objective of this study was to assess knee function after anterior cruciate ligament reconstruction focusing on residual donor-site problems. Ninety consecutive patients with chronic unilateral anterior cruciate ligament rupture were operated on by the same surgeon using patellar tendon autografts, the all-inside arthroscopic technique, and interference screw fixation. At the follow-up examination 24 (range 22-32) months after the index operation, the median total anterior-posterior KT-1000 side-to-side difference was 2.5 (-7 to 11) mm. The median Lysholm score was 86 (range 37-100) points and the median Tegner activity level was 6 (range 1-9). Using the IKDC evaluation system, 62 of 90 (69%) were classified as normal or nearly normal. The median one-leg-hop quotient was 93 (range 0-167)% of the uninjured leg. Of 90 patients, 44 (49%) had minor or no discomfort when asked to walk on their knees (kneewalkers) and 46 of 90 (51%) patients had severe problems or found it impossible to perform the test (non-kneewalkers). The 'kneewalkers' had a median loss of anterior knee sensitivity of 10 (range 0-120) cm2. The corresponding value for the 'non-kneewalkers' was 25 (range 0-200) cm2 (P = 0.0001). Palpatory donor-site tenderness was registered in 19 of 44 (43%) of the 'kneewalkers' and 37 of 46 (80%) of the 'non-kneewalkers' (P < 0.001). Full hyperextension was not regained by 9 of 44 (20%) of the 'kneewalkers' and 19 of 46 (41%) of the 'non-kneewalkers' (P < 0.05). Additional surgery during the follow-up period was required by 6 of 44 (14%) of the 'kneewalkers' and 19 of 46 (41%) of the 'non-kneewalkers' (P < 0.01). Magnetic resonance imaging focusing on the donor site was performed on 31 randomly selected patients and revealed no difference between the 'kneewalkers' and the 'non-kneewalkers' in terms of patellar tendon width, thickness, length, and residual donor-site gap size. The kneewalking test was found to be a functional and reliable test for detecting donor-site morbidity. It appears that donor-site morbidity was related to problems requiring additional surgery during the follow-up period, such as extension deficit and pain near the metal implant on the tibial side, as well as the loss of anterior knee sensitivity. It appears to be important to attempt to preserve the sensitivity in the operated area during surgery and to regain full hyperextension in the postoperative period to minimize donor-site morbidity.

Perioperative management of children.

Along with the decision for surgery in children comes a concern for the development of minor psychological disturbances close to the event and possibly also later in life. There is always also anxiety for the procedure and its influence on normal physiological functions. It is true that these matters are valid also in the adult. There are, however, two factors that differ. One is the special relationship to family or legal guardian and the other is the skill needed to communicate with infants, pre-school children and other children.