Intraoperative monitoring of recurrent laryngeal nerve function.

Intraoperative recurrent laryngeal nerve identification is sometimes difficult in reoperative cervical dissection or operation for inflammatory thyroid disorders. Three modalities have been described to intraoperatively assess nerve function: vocal cord visualization with fiberoptic bronchoscopy or direct laryngoscopy, electromyelographic surveillance of arytenoid muscle function, and cord function assessment with an electromyelogram-electrode endotracheal tube. Our study focused on patients requiring cervical dissection for thyroid or parathyroid disease in which intraoperative recurrent laryngeal nerve function was monitored by nerve stimulation with a concentric bipolar probe. Impulses were tracked via a specialized electrode-bearing endotracheal tube with signal transduction to a recording monitor. No operative nerve injuries occurred in the patients of our study group. This surveillance technique's several advantages include use of standard intubation techniques with no increase in operative time, nerve stimulation tracings that are quantifiable and reproducible with production of a permanent record, and less subjectivity due to observer variability. We believe these factors make the electromyelogram-electrode endotracheal tube approach to intraoperative recurrent laryngeal nerve assessment the optimal technique.

Evaluation of a new laser-resistant fabric and copper foil-wrapped endotracheal tube.

The risk of an endotracheal tube's combustion during laser airway surgery necessitates the use of special anesthetic techniques and equipment to prevent this complication. This study was designed to evaluate the Laser-Trach(TM), a new laser-resistant rubber endotracheal tube for use during laser airway surgery. The Laser-Trach endotracheal tubes that were evaluated were size 6.0 mm internal diameter (ID) red rubber endotracheal tubes which had been commercially wrapped by Kendall-Sheridan (Mansfield, Mass.) with copper foil tape and overwrapped with fabric. The fabric layer was saturated with water prior to our tests, as recommended by the manufacturer. The Laser-Trach endotracheal tubes were compared with plain (bare) size 6.0 mm ID Rusch red rubber endotracheal tubes. The tubes under study were positioned horizontally on wet towels in air and had 5 L x min(-1) of oxygen flowing through them. They were subjected to continuous laser radiation at 40 W from either a CO2 or an Nd-YAG laser. The Nd-YAG laser was propagated via a 600-micron fiber bundle. Each laser was directed perpendicularly at the shaft of the endotracheal tube being studied, and its output was continued until a blowtorch fire occurred or 60 seconds had elapsed. Sixty seconds of CO2 laser fire did not ignite any of the eight Laser-Trach endotracheal tubes tested. However, blowtorch ignition of all eight bare rubber tubes tested occurred after 0.87 +/- 0.21 (mean +/- SD) seconds of CO2 laser fire. Nd-YAG laser contact with the Laser-Trach endotracheal tubes caused the perforation and blowtorch ignition of all eight tubes tested after 18.79 +/- 7.83 seconds. This was a significantly (P<.05) longer time than the 5.45 +/- 4.75 seconds required for the blowtorch ignition of all eight plain rubber endotracheal tubes tested with the Nd-YAG laser. Our results show that under the conditions of this study, the shafts of the Kendall-Sheridan Laser-Trach endotracheal tubes were resistant to the C02 laser. However, this endotracheal tube is not recommended for use with the Nd-YAG laser.

Advantage of rubber over plastic endotracheal tubes for rapid extubation in a laser fire.

The occurrence of airway fires during laser airway surgery necessitates the use of special techniques to improve patient safety. For example, it is recommended that the endotracheal tube cuff be inflated with saline. However, in the event of an endotracheal tube fire, the tube must be quickly removed. This study was designed to determine the time necessary for red rubber (RR) or polyvinylchloride (PVC) endotracheal tubes to be removed from a model airway after inflating the cuffs with saline. A model larynx and trachea was suspended vertically. It was intubated with either 7.0 RR or PVC endotracheal tubes. Six milliliters of saline was used to inflate the endotracheal tube cuffs. After inflation, a clamp was used to occlude the pilot tube on the RR endotracheal tubes. A 4-lb weight was then suspended from the endotracheal tube. The time to spontaneous extubation of the model trachea after unclamping the pilot tubes on 12 RR endotracheal tubes was determined. For the PVC endotracheal tubes, the times to spontaneous extubation using the 4-lb weight were determined in 12 endotracheal tubes after cutting the pilot tube and in 12 by maximum aspiration of the saline from the endotracheal tube cuff with a 10-ml syringe. A time of 0.94 +/- 0.10 sec (mean +/- SD) was required for spontaneous extubation of the RR endotracheal tubes after unclamping the pilot tube. For the PVC endotracheal tubes, extubation occurred 3.28 +/- 1.08 and 1.81 +/- 0.60 sec after cutting the pilot tube or deflating the cuff with a syringe, respectively. The mean times for each of the 3 groups were significantly different (p < 0.05) from each other as determined by the ANOVA. This study shows that if PVC endotracheal tubes are used, deflation of the saline-filled cuff by aspiration with a 10-ml syringe is faster than cutting the pilot tube. Unclamping the pilot tube on the RR endotracheal tubes resulted in the fastest time to endotracheal extubation.

Spinal phobia: survey results of patient attitudes and preferences regarding anesthesia.

STUDY OBJECTIVE: To determine unbiased patient preferences for either spinal or general anesthesia for upcoming surgeries. DESIGN: Prior to contact with anesthesia personnel, a simple questionnaire was completed by surgical patients to determine their demographic characteristics and previous anesthetic experiences. Their concerns regarding a list of complications of general and spinal anesthesia and their preferences for general or spinal anesthesia if either method could be used were also determined. SETTING: University-affiliated suburban community hospital. MEASUREMENTS AND MAIN RESULTS: The survey was completed by 254 patients. A preference for general over spinal anesthesia was expressed by 80.2% of the patients responding. They expressed significantly more concerns regarding nausea/vomiting, sore throat, feeling sleepy, and death with general anesthesia than with spinal anesthesia. Concerns of back pain, nerve damage and paralysis were statistically related to spinal anesthesia. CONCLUSIONS: This survey shows a strong patient preference for general anesthesia and a phobia for spinal anesthesia.

Propofol, but not thiopental, supports the growth of Candida albicans.

We determined whether propofol, thiopental, or 0.9% saline would serve as a growth medium for Candida albicans. In Part I, we investigated whether opening 20 propofol ampules would cause glass particles from the exterior of the ampule to fall into the emulsion and contaminate it. Each ampule was painted with red fingernail polish and its contents were passed through filter paper after it was opened in a routine manner. In Part II, a sample from a colony of C albicans was added to sterile vials containing 20 mL of either 0.9% saline, 1% propofol, or 2.5% thiopental. A 1-microL sample from each vial was then plated onto Sabaroud's dextrose plus brain-heart infusion (SABHI) agar at the following times after inoculation: 0, 3, 6, 16, and 24 h. The plates were incubated at 35 degrees C for 24 h and the number of colony-forming units counted. The filtration of two of the painted ampules in Part I revealed red glass fragments. In Part II, the saline and thiopental solutions did not increase the number of colonies of C. albicans by 24 h. However, the propofol, after a latent period between 6 and 16 h, supported the growth of C. albicans at a rapid rate. Our investigation shows that glass particles from the exterior of a propofol ampule can contaminate its contents when the ampule is opened in a routine manner. Furthermore, propofol provides an excellent growth medium for C. albicans. Thiopental and saline showed no growth. We conclude that the ability of propofol to grow C. albicans necessitates rigorous standards of sterility in its handling.

Multidimensional Pain Inventory profile classifications and psychopathology.

The Multidimensional Pain Inventory (MPI) and the MMPI have been used widely to assess chronic pain patients. This study examined the relationship between patient profile classifications generated by the MPI and psychopathology as measured by the MMPI. MPI Dysfunctional and Interpersonally Distressed means were significantly different than the MPI Adaptive Coper means on scales 4, 6, 7, and 8 of the MMPI. The Dysfunctional and Adapative Coper means were also significantly different on MMPI scale 2. MMPI profiles for 79% classified as Dysfunctional and 62% classified as Interpersonally Distressed displayed psychopathology as defined by significant two-point scale elevations. Only 23% of those classified as Adaptive Copers had significant two-point MMPI scale elevations.

Metal anesthesia circuit components stop the progression of laser fires.

STUDY OBJECTIVE: To determine whether metallic Y-pieces and elbows would halt the progression of a laser-induced endotracheal tube fire. DESIGN: A segment of polyvinyl chloride endotracheal tube was attached to either an all-plastic anesthesia circle breathing system (n = 5) or a circuit consisting of a metal Y-piece and elbow with plastic hoses (n = 5). In each case, an Nd-YAG laser was used to ignite the endotracheal tube segment and attached anesthesia circuit as 5 L/min of oxygen was flowing through them. SETTING: Research laboratory of a university-affiliated metropolitan medical center. MEASUREMENTS AND MAIN RESULTS: The flames from the endotracheal tubes burned through the 22 mm hoses that were part of the all-plastic circuits in 49.5 +/- 8.8 seconds (mean +/- SD). In none of the trials with the metal components did the fire advance beyond the endotracheal tube's 15 mm adapter. CONCLUSIONS: Metal circuit components halt the progression of laser-induced endotracheal tube fires toward the anesthesia machine.

Growth of Staphylococcus aureus in four intravenous anesthetics.

Patient infections related to the use of propofol have been reported. To investigate the growth of Staphylococcus aureus in propofol, thiopental, methohexital, etomidate, and 0.9% saline containing no bacteriostatic drug, these preparations were inoculated and samples were plated onto blood agar at 0, 3, 6, 21, 24, and 27 h. The number of colony-forming units (CFU) on the plates was then determined after 24 h of incubation. Samples from the inoculated etomidate solution showed zero CFU at 3 h and thereafter, whereas 21 h were required by the methohexital and thiopental solutions to reduce the number of CFU to zero. For normal saline, no significant change in CFU was seen before the first 6 h, then the number of CFU gradually declined, although some S. aureus CFU were still present at 27 h. Inoculation of the propofol emulsion resulted in a substantial growth of S. aureus between 6 and 21 h after inoculation. We conclude that, of the preparations tested, only propofol was an excellent medium for the rapid growth of S. aureus. Meticulous sterile technique, therefore, is advised when handling it.

Evaluation of foil coverings for protecting plastic endotracheal tubes from the potassium-titanyl-phosphate laser.

The potassium-titanyl-phosphate laser is being used for airway surgery and could cause an endotracheal tube fire. To determine whether five different metallic foil tapes or the Laser-Guard protective wrap would protect polyvinylchloride (PVC) endotracheal tubes from this laser, it was set to a power of 18 W and aimed at the wrapped endotracheal tube under study for up to 1 min while 5 L/min of oxygen flowed through the endotracheal tube. A plain (unwrapped) PVC endotracheal tube was studied also. The plain PVC endotracheal tube was ignited by the laser after 14 s. Potassium-titanyl-phosphate laser radiation did not significantly affect the nonadhesive sides of the foil tapes tested or the Laser-Guard covering. However, potassium-titanyl-phosphate laser radiation caused ignition or melting of underlying PVC endotracheal tubes when it was applied to the endotracheal tubes with the adhesive side of the foil tapes facing outward. It is concluded that only the Laser-Guard protective coating adequately protected the PVC endotracheal tubes tested under the conditions of this experiment.

Hemodynamic responses to endotracheal extubation after coronary artery bypass grafting.

After coronary artery bypass grafting (CABG) surgery, patients may remain at risk for myocardial ischemia and infarction and ventricular dysrhythmias. The hemodynamic responses to endotracheal extubation and the efficacy of intravenous lidocaine pretreatment were studied after CABG surgery and overnight mechanical ventilation. Twenty-five patients were divided into two groups: group 1 (n = 13) patients who had tracheal extubation after pretreatment with a placebo; group 2 patients who received lidocaine (1 mg/kg IV) before tracheal extubation. Hemodynamic data, electrocardiographic tracings, and arterial blood gases were obtained before tracheal extubation, during suctioning, and 1, 5, and 20 min after tracheal extubation. Group 1 patients displayed significant increases in heart rate, arterial blood pressure, rate-pressure product, right atrial pressure, and cardiac index during suctioning and within 1 min of tracheal extubation, returning to preextubation level by 5 min. There were no significant changes in pulmonary and systemic resistance indices. Hemodynamic changes in group 2 patients were similar to those in group 1. Both in the absence and presence of lidocaine, tracheal extubation caused hemodynamic responses that were small in magnitude and brief in duration. These responses were not associated with electrocardiographic or enzymatic evidence of myocardial ischemia or infarction, or with ventricular dysrhythmias. Compared with the well-documented hemodynamic responses to tracheal intubation, we found that extubation of the trachea after CABG surgery was associated with less pronounced responses. This may be related to avoidance of laryngoscopy and possibly accommodation to the endo-tracheal tube. These modest hemodynamic responses of extubation of the trachea after CABG surgery were not modified by intravenous lidocaine.

Eliciting assessment data from the patient who is difficult to interview.

The patient interview is an essential part of the assessment phase of the nursing process. Ensuring a productive interview involves controlling, as much as possible, the interview environment as well as the nurse's verbal and nonverbal communication. Patients who are cognitively impaired, angry, anxious, depressed, manipulative, or seductive can make this interview process more challenging. Working individually with each of these possible patient dynamics in a calm, controlled, and knowledgeable way can help facilitate the interview process and pave the way for fewer problems in the future. Frequently, the interview may involve the discussion of sensitive topics such as terminal illness, suicide, or sexuality. Gathering information and developing a comfort level in broaching these issues with patients are important goals for nursing professionals. Reading, attending workshops, consultation with professionals, and most important, self-assessment of these sensitive topics are all useful tools in obtaining those goals.

Effect of helium-neon and infrared laser irradiation on wound healing in rabbits.

We examined the biostimulating effects of helium-neon laser radiation (HeNe; 632.8 nm), pulsed infrared laser radiation (IR; 904 nm), and the two combined on skin wound healing in New Zealand white rabbits. Seventy-two rabbits received either 1) no exposure, 2) 1.65 J/cm2 HeNe, 3) 8.25 J/cm2 pulsed IR, or 4) both HeNe and IR together to one of two dorsal full-thickness skin wounds, daily, for 21 days. Wound areas were measured photographically at periodic intervals. Tissue samples were analyzed for tensile strength, and histology was done to measure epidermal thickness and cross-sectional collagen area. Significant differences were found in the tensile strength of all laser-treated groups (both the irradiated and nonirradiated lesion) compared to group 1. No differences were found in the rate of wound healing or collagen area. Epidermal growth was greater in the HeNe-lased area compared to unexposed tissue, but the difference was not significant. Thus, laser irradiation at 632.8 nm and 904 nm alone or in combination increased tensile strength during wound healing and may have released tissue factors into the systemic circulation that increased tensile strength on the opposite side as well.

Minimal positive end-expiratory pressure (PEEP) may be "best PEEP".

In the absence of clinical trials, positive end-expired pressure (PEEP) has been accepted as efficacious for treatment of postoperative decreases in arterial oxygen tension (PaO2) from a variety of causes including adult respiratory distress syndrome (ARDS). PEEP is thought to increase PaO2 by alveolar recruitment, which in turn, has been hypothesized to play a decisive role in pulmonary recovery. One hundred and eighteen patients were followed prospectively, and after development of decreased PaO2, randomized to receive recruitive PEEP (determined by blood gas criteria) or supportive PEEP (the minimal PEEP required to maintain PaO2 above 60 mm Hg on .5 inspired O2 fraction (FIO2). No prognostic factors were significantly different between the two groups. Recruitive PEEP application in 22 patients yielded a significantly increased incidence of hypotension (55 percent), pneumothorax (20 percent), and death during treatment (27 percent) when compared to the 28 supportive PEEP patients who had no hypotension or pneumothorax and only one death during treatment (4 percent). After PEEP treatment, deaths in each group were similar (19 percent and 15 percent, respectively). We find no evidence that PEEP treatment promotes beneficial outcomes and conclude that recruitment attempts may be harmful.

Vasopressor challenges during chronic MAOI or TCA treatment in anesthetized dogs.

Ten male mongrel dogs were treated in Phase I with tranylcypromine, 6 mg/kg IM b.i.d., for 21 days. Dogs were anesthetized at weekly intervals before, during, and up to four weeks after drug treatment with a combination of amylbarbital, 25 mg/kg, 1% enflurane in 70:30 N2O:O2 and fentanyl, 500 mcg. Bolus IV injections of norepinephrine, 0.1-0.6 mcg/kg, and ephedrine, 0.03-0.12 mg/kg were given while continuously recording arterial blood pressure, lead II of the ECG, heart rate, and rectal temperature. Awakening times were noted. In Phase II, the dogs were given imipramine, 25 mg/kg IM b.i.d., for 21 days. During Phase III, 14 days of tranylcypromine, 7 days of tranylcypromine plus imipramine, and 7 days of imipramine were administered. Anesthetic techniques were repeated in phases II and III. The fourth phase consisted of tranylcypromine injections, 6 mg IM b.i.d., and anesthesia with amylbarbital, 25 mg/kg, 2.5% enflurane in 70:30 N2O:O2. Vasopressor challenges were repeated during each phase of the study. Following induction of anesthesia and prior to fentanyl challenge, baseline blood pressures and heart rates did not differ from control in Phase I, II, and III of this study. Responses to norepinephrine during all of the tranylcypromine phases were not significantly different from control but ephedrine responses were prolonged, peaking by the second week of treatment. During Phase II, dysrhythmias occurred following norepinephrine and ephedrine with one lethality following norepinephrine, 0.2 mcg/kg. Responses to norepinephrine and awakening times were significantly greater during Phase II compared to Phase I. In Phase III, during the first week of combined therapy the responses to norepinephrine were significantly greater than any other week of this phase. During Phase IV, resting blood pressure and the ephedrine responses were significantly increased during tranylcypromine when the anesthesia regimen did not include fentanyl. These results suggest that during initial treatment with tranylcypromine or imipramine, cardiovascular responses to vasopressor challenges were predicted by the pharmacology of the antidepressant. During tranylcypromine phases, we did not observe exaggerated cardiovascular effects during anesthesia and vasopressor challenges as had been previously reported.

Anxiety disorders and psychiatric referral in the general medical emergency room.

A retrospective chart review of patients seen in the medical emergency room between July 1983 and July 1984 indicated that only one third of the patients who received a final diagnosis that included anxiety were referred for psychiatric follow-up. This was in sharp contrast to the referral pattern from the ER of depressed or psychotic patients. In the present study, referred and nonreferred patients were compared on 17 variables to determine those factors that influenced decision to refer. Among the five factors that discriminated between the criterion groups were age, depression, and lack of concomitant medical findings.