Emboli and cognitive state in surgical vs. transcatheter aortic valve replacement.

Background Neurologic complications and neurocognitive impairment due to cerebral emboli are common following heart surgery. This study aimed to compare the number of emboli detected in the middle cerebral artery in open aortic valve replacement, apical and femoral transcatheter aortic valve replacement, and also to test for an association between the number of emboli captured in each procedure and changes in the patient's cognitive state. Methods Forty-four patients were enrolled in the study, 36 of whom were included in the final analyses: 14 underwent open aortic valve replacement, 2 had femoral transcatheter aortic valve replacement, and 10 had apical transcatheter aortic valve replacement. The number of emboli was detected by middle cerebral artery intraoperative transcranial Doppler ultrasound. The day before the elective surgery and 6-12 weeks later, all patients underwent neurocognitive evaluations by the Mini-Mental State Examination; the difference was tested for an association with the number of emboli. Results Open aortic valve replacement resulted in a significantly greater number of emboli (8555, range 2999-12489) than apical (1962, range 521-3850) or femoral (1220, range 948-1946) transcatheter approaches ( p = 0.003). Both transcatheter approaches yielded a comparable amount of emboli ( p = 0.798). No significant association was observed between the change in Mini-Mental State Examination score and the mean number of emboli ( r = 0.026; p = 0.907). Conclusions Compared to transcatheter aortic valve replacement, more cerebral emboli are detected during surgical aortic valve replacement; however, this does not appear to adversely affect a patient's cognitive state.

Rapid atrial fibrillation following tube thoracostomy insertion.

We report a case of trauma patient, whose heart rhythm and rate changed from sinus tachycardia to rapid atrial fibrillation. The change occurred immediately after the insertion of left thoracostomy tube. The patient did not respond to pharmacological treatment. Only when the tube was pulled out, the rhythm returned to sinus. Chest radiogram shows the position of the tube, in close proximity to the cardiac silhouette.

Hemodynamic and catecholamine response to tracheal intubation: direct laryngoscopy compared with fiberoptic intubation.

STUDY OBJECTIVE: To compare the stress response following tracheal intubation using direct laryngoscopy to that using fiberoptic bronchoscopy technique. DESIGN: Randomized, prospective study. SETTING: Operating rooms in a teaching hospital. PATIENTS: 51 ASA physical status I and II patients who were scheduled for an elective surgery with general anesthesia. INTERVENTIONS: Patients were randomly assigned to receive either direct laryngoscopy or fiberoptic orotracheal intubation, as part of general anesthesia. A uniform protocol of anesthetic medications was used. MEASUREMENTS: Blood pressure and heart rate were measured before induction, before endotracheal intubation, and 1, 2, 3, and 5 minutes afterwards. Catecholamine (epinephrine and norepinephrine) blood samples were drawn before the induction, and 1 and 5 minutes after intubation. MAIN RESULTS: Duration of intubation was shorter in the direct laryngoscopy group (16.9 (16.9 +/- 7.0 sec, range 8 to 40) compared with the fiberoptic intubation group (55.0 +/- 22.5 sec, range 29 to 120), p < 0.0,001. In both groups, blood pressure and heart rate were significantly increased at 1, 2, and 3 minutes after intubation, but there was no significant difference between the two study groups. Catecholamine levels did not increase after intubation and did not correlate with the hemodynamic changes. CONCLUSIONS: The use of either direct laryngoscopy or fiberoptic bronchoscopy produces a comparable stress response to tracheal intubation. Catecholamine levels do not correlate with the hemodynamic changes.

Predicting difficult airways using the intubation difficulty scale: a study comparing obese and non-obese patients.

STUDY OBJECTIVE: To compare intubation difficulty in obese and non-obese patients by intubation difficulty scale (IDS), intubation duration measurement, and oxygen saturation (SaO(2)) levels. DESIGN: Prospective, controlled study. SETTING: Operating room of a tertiary-care hospital. PATIENTS: 204 ASA physical status I, II, and III adult patients who underwent elective surgery with endotracheal intubation. INTERVENTIONS AND MEASUREMENTS: Preoperative airway parameters, intubation duration, IDS scores, and lowest SaO(2) during intubation were recorded. MAIN RESULTS: IDS scores were higher in the obese group than the non-obese (2.29 +/- 0.45 and 1.26 +/- 0.2, respectively, P = 0.03). Intubation duration was 45.1 +/- 6 sec for obese versus 36.8 +/- 2.6 sec for the non-obese group (P = 0.20). The lowest SaO(2) recorded was 97%, with no difference noted between groups. Mallampati class >or=3 was found to positively predict intubation difficulty scores greater than 5. CONCLUSIONS: Difficult intubation was more prevalent among obese than non-obese patients, but intubation duration and lowest SaO(2) levels during intubation were not. Moreover, the modified Mallampati test was found to be a moderately good (60%) predictor of difficult intubation among obese patients.

Thoracic epidural local anesthetics are ineffective in alleviating post-thoracotomy ipsilateral shoulder pain.

OBJECTIVE: This study was conducted to estimate the incidence and clinical predictors of post-thoracotomy shoulder pain and to determine the effectiveness of thoracic epidural block in alleviating this pain. DESIGN: A prospective clinical trial. SETTING: University teaching hospital. PARTICIPANTS AND INTERVENTIONS: Thirty-two adult patients undergoing elective thoracic surgery consented to participate in the study. All operations were open thoracotomies done by the same team of surgeons and anesthesiologists. A thoracic (T6) epidural catheter was placed before induction of general anesthesia. Each patient received 7 mL of lidocaine 2% epidurally and repeated doses of 5 mL of lidocaine 2% every half hour during the operation. Postoperatively, the occurrence of incision or ipsilateral shoulder pain was observed and treated with a maximal dose of 5 mL of lidocaine 2%. If ineffective, indomethacin suppository (nonsteroidal anti-inflammatory drug [NSAID]) was given. Variables such as patient's age, sex, American Society of Anesthesiologists physical status, type, site and duration of surgery, duration of anesthesia, the resection of main bronchus, and the use of thoracostomy tubes were recorded. MEASUREMENTS AND MAIN RESULTS: Postoperatively, 10 patients (31%) had shoulder pain, 4 patients (12.5%) complained of incision pain, and 2 (6.3%) complained of both incision and shoulder pain. A bolus of 5 mL of lidocaine 2% in the epidural catheter relieved incision pain in all the patients, but was ineffective for shoulder pain. Indomethacin suppository was effective in these patients. No correlation was found between any variable and the occurrence of shoulder pain. CONCLUSIONS: It is concluded that post-thoracotomy shoulder pain is a common problem, and the previously mentioned variables did not predict its appearance. Thoracic epidural block is effective in the treatment of incision but not shoulder pain. The NSAID indomethacin suppository was found to be effective for that problem.

Propofol does not induce pulmonary dysfunction in stressed endotoxic pigs receiving Intralipid.

OBJECTIVE: To assess the effect of diisopropyl phenol (propofol), with and without Intralipid, on the cardiopulmonary system and on thromboxane production in endotoxic pigs. DESIGN: Prospective, randomized animal study. SETTING: Animal research laboratory at a major teaching hospital. SUBJECTS: Twenty-four pigs, divided into three groups (n = 8). INTERVENTIONS: Pulmonary arterial catheters and arterial cannulas were inserted into all pigs. Each pig received a 30 ng/kg bolus of endotoxin at 1 hr, followed by a continuous infusion of endotoxin at 24 ng x kg-1 x hr-1. Diisopropyl phenol at 25, 75, and 200 microg x kg-1 x min-1 was administered to all pigs, beginning at 1, 2, and 3 hrs, respectively. The pigs were divided into three groups to receive 0.25 g x kg-1 x hr-1, 0.08 g x kg-1 x hr-1, or no Intralipid, starting at time t = 0. Heart rate and mean arterial, central venous, and pulmonary arterial pressures were recorded continuously. Core temperature, arterial blood gases, mixed venous oxygen saturation, pulmonary arterial occlusion pressure, and cardiac output were measured intermittently. Thromboxane B(2) concentrations were measured at baseline and at 60, 75, 120, 135, 180, 195, and 240 mins. Data are expressed as mean +/- sd. Groups were compared by using repeated analysis of variance, with p <.05 used for statistical significance. MEASUREMENTS AND MAIN RESULTS: All pigs completed the 4-hr study. Marked variabilities were noted for individual pigs. Following the infusion of endotoxin, compared with baseline, there was a significant increase in pulmonary vascular resistance and a decrease in Pao(2) (p <.001 and p <.008, respectively). This response was not affected by the increasing dose of diisopropyl phenol, nor were there differences between the Intralipid and control groups. Pao(2) remained significantly lower in all groups, compared with the baseline measurements (p <.001) over the 4 hrs of the experiment. Thromboxane B(2) concentrations remained elevated compared with baseline and were significantly higher (p <.05) in the high-dose Intralipid group, compared with the low-dose and the control groups, during the last hour of the experiment. CONCLUSIONS: Small doses of endotoxin, when given to pigs, induce major perturbations of cardiopulmonary function. Neither Intralipid, high vs. low dose, nor diisopropyl phenol, at sedating vs. anesthetizing doses, worsened the physiologic derangement associated with the stress of low-dose endotoxemia.

Anaphylactic reactions to isosulfan blue dye during sentinel node lymphadenectomy for breast cancer.

IMPLICATIONS: Intraoperative use of isosulfan dye for lymphatic mapping may result in anaphylaxis. Furthermore, in some patients, intravascular absorption of isosulfan may induce serum discoloration causing interference with pulse oximetry function.

Performance of infusion pumps during hyperbaric conditions.

BACKGROUND: Many hyperbaric facilities use infusion pumps inside the chamber. It is therefore important to ensure that this equipment will perform accurately during hyperbaric conditions. The authors tested the function and accuracy of the Imed 965 and Infutec 520 volumetric infusion pumps, the Easy-pump MZ-257 peristaltic infusion pump, and the Graseby 3100 syringe pump. METHODS: The authors calculated the deviations of infused volumes at low and high rates (12-18 and 60-100 ml/h) on three different hyperbaric protocols (up to 2.5, 2.8, and 6 atmospheres absolute [ATA]), resembling a standard hyperbaric oxygen treatment and US Navy treatment tables used for decompression illness and for arterial gas embolism. Two examples of each pump model were examined in every experiment. RESULTS: The Easy-pump MZ-257 failed to function completely beyond a chamber pressure of 1.4 ATA, making it unsuitable for use inside the hyperbaric chamber. The Graseby 3100 failed to respond to all keyboard functions at 2.5-2.8 ATA, making it unsuitable for use in most hyperbaric treatments. The Imed 965 performed within an acceptable volume deviation (< or =10%) during most hyperbaric conditions. During the compression phase of the profiles used, and for the low infusion rates only, exceptional volume deviations of 20-40% were monitored. The Infutec 520 demonstrated an acceptable deviation (within 10%) throughout all the hyperbaric profiles used, unaffected by changes in ambient pressure or infusion rate. CONCLUSIONS: Commercially available infusion pumps operating during hyperbaric conditions demonstrate substantial variations in performance and accuracy. It is therefore important that the hyperbaric facility staff make a careful examination of such instruments to anticipate possible deviations in the accuracy of the equipment during use.