Joan M. Christie

Unplanned endotracheal extubation in the intensive care unit

STUDY OBJECTIVE To identify the frequency, outcome, and factors associated with unplanned endotracheal extubation (UE) in the intensive care unit (ICU). DESIGN Prospective study. SETTING An urban, university trauma-surgical ICU. PATIENTS 96 intubated ICU patients who underwent 101 episodes of UE. INTERVENTIONS Patient, nursing, respiratory, and demographic factors associated with UE and patient outcome were determined for one year. Results were presented to nursing staff. The incidence of UE as a function of the total number of ventilator days was determined for one year post nursing education. ENDPOINTS Patients with UE were identified. Patients with reintubation were followed until final extubation. MEASUREMENTS AND MAIN RESULTS 85% of UE were self-extubations and 15% were accidental. Self-extubations occurred with equal frequency during all three nursing shifts in alert or agitated patients who were not being weaned. Accidental extubations occurred during the day shift in less alert patients and were associated with transport procedures and the use of rotary beds. Overall, 57% of patients were reintubated and most reintubations were in the first hour. Difficulty with reintubation was common, and one patient who could not be reintubated died. There were significantly fewer UE per ventilator day after nursing education. CONCLUSIONS Patients should be observed closely after unplanned extubation, although many may not require reintubation. Reintubation can be quite difficult, necessitating highly skilled airway management. Attention to associated risk factors may decrease the incidence of both accidental and self-extubation.

Absence of neuropathic pelvic pain and favorable psychological profile in the surgical selection of patients with disabling interstitial cystitis

PURPOSE We evaluated the results among patients with disabling interstitial cystitis treated by cystectomy, urethrectomy and creation of a continent colonic urinary reservoir (the Florida pouch). The value of psychological evaluation and pain localization techniques, as well as the use of a team approach in the evaluation of these patients were assessed. MATERIALS AND METHODS The 20 women and 2 men who underwent surgery for disabling interstitial cystitis ranged from 31 to 75 years old (mean age 48). The duration of symptoms ranged from 2 to 14 years (mean 7). All patients had undergone multiple prior therapies, including vesical hydrodistension, instillations, laser treatments, and use of tranquilizers and a variety of pain medications. Patients underwent a clinical, cystoscopic (with bladder biopsies) and urodynamic evaluation as well as examination by a gynecologist with expertise in vaginal ultrasonography. The last 5 patients underwent psychological evaluation and pain localization techniques. RESULTS Among the clinical parameters, the presence of a small capacity bladder with the patient under anesthesia (less than 400 cc) was associated with the best surgical results. Among 11 patients evaluated only clinically success was achieved in 64%, while all 5 (100%) who also underwent pain localization techniques and psychological evaluation had a successful outcome postoperatively. The overall surgical success rate in the 22 patients was 73%. Two patients undergoing psychological evaluation and pain localization techniques were not considered to be surgical candidates. Among 7 surgical failures 4 patients underwent postoperative psychological evaluation and pain localization techniques, and they would not have been considered candidates for surgery with the new parameters. CONCLUSIONS A team approach is essential in the evaluation of these patients. Following the initial selection of patients who had a small bladder capacity while under anesthesia, psychological evaluation and pain localizing techniques may assist surgeons in selecting those who would benefit from a radical operation.

Computerized axial tomography to define the distribution of solution after stellate ganglion nerve block

STUDY OBJECTIVE To define the spread of local anesthetic after C6 stellate ganglion nerve block using computerized axial tomography (CAT). DESIGN Prospective, open descriptive study. SETTING Outpatient pain consult center. PATIENTS 10 ASA status I patients undergoing stellate ganglion nerve blocks for sympathetically maintained pain. INTERVENTIONS Radiocontrast and local anesthetic was given in 5 ml increments to 20 ml total volume for C6 stellate ganglion nerve blocks in eight patients and C7 in two patients. MEASUREMENTS AND MAIN RESULTS CAT scanning was performed at baseline and after 5, 10, 15, and 20 ml of injectate was administered. Cervical level and pattern of injectate spread was recorded after each increment. Neck pressure above C6 did not promote caudal spread. One half of the injections were beneath prevertebral fascia. Injections on top of the fascia spread more diffusely around C6. All injections in high volume reached the medial aspect of T1 around the head, not neck, of the first rib. CONCLUSIONS Solutions injected for C6 stellate ganglion nerve block concentrate medial to the stellate ganglion at T1. Thus, they must produce upper extremity sympathectomy by a mechanism other than contact with the ganglion.

Head turning in brain death

Criteria for determination of brain death in adults have been defined. Spinal cord reflexes may persist after brain death. We present the case of a brain dead patient who had a complex spinal automatism resulting in head shaking and arm extension. The report reviews guidelines for the diagnosis of brain death and discusses complex spinal cord reflexes in brain dead patients.

Acute trauma alters morphine clearance

Trauma is accompanied by changes in liver perfusion and acute phase proteins. Such changes have the potential to alter drug metabolism. There are few studies describing drug disposition in acute trauma. We determined the pharmacokinetics of an intermediate extraction drug, morphine, in trauma patients. Nine patients with an Injury Severity Score (ISS) > or = 16 were studied within 48 hours of trauma. Morphine 5 mg was given intravenously and serial blood and urine samples were drawn to derive pharmacokinetic parameters. Alpha acid glycoprotein (AAG) levels were determined. Total morphine clearance (CL) and volume of distribution (Vss) were decreased compared to established literature values. Area under the curve (AUC) and terminal half-life (T 1/2 alpha) were increased. AAG levels were higher than reference range. Elimination half-life was increased. The decrease we observed in Vss may be attributed to increased binding of morphine by AAG, which is increased after trauma as in our patients. Decreased clearance and increased half-life of an intermediate extraction drug may be explained by increased protein binding, decreased liver blood flow, and reduced hepatocellular function. Decreased clearance of the magnitude observed in these patients could result in drug accumulation. Better understanding of the effects of trauma on the pharmacokinetics of low, high, and intermediate extraction drugs will prevent excessive or suboptimal drug dosing.

Phenytoin Protein Binding and Dosage Requirements during Acute and Convalescent Phases following Brain Injury

OBJECTIVE: TO longitudinally evaluate unbound and total serum Phenytoin concentrations during intravenous phenytoin maintenance dosage and to determine the relationship among phenytoin protein binding, serum albumin, and unbound fatty acid concentrations in patients with head injuries during intensive care unit (ICU) and convalescent care. DESIGN: Serum albumin and phenytoin unbound fraction were determined twice weekly during ICU and convalescent care in 10 patients receiving phenytoin following acute brain injury. Phenytoin protein binding was also determined in 10 healthy control subjects. MAIN OUTCOME MEASURES: Longitudinal serum phenytoin concentrations associated with dosage adjustments targeted to achieve unbound phenytoin serum concentrations between 1.0 and 2.0 mg/L were documented during ICU and convalescent care. Longitudinal phenytoin protein binding was correlated with serum albumin and unbound fatty acid concentrations in neurotrauma patients. RESULTS: ICU patients received intravenous therapy for a mean of 15.0 days. The mean ± SD initial phenytoin intravenous dosage regimen of 6.0 ± 0.7 mg/kg/d resulted in mean ± SD total and unbound phenytoin concentrations of 3.2 ± 2.3 and 0.3 ± 0.2 mg/L. Two patients had seizures associated with low phenytoin concentrations. Four patients continued to receive oral phenytoin therapy during convalescent care; phenytoin dosage requirements decreased over time in these patients. During acute and convalescent care, the phenytoin unbound fraction ranged from 6.0% to 18.3% and correlated with albumin (r2 = 0.61, p < 0.0001) but did not correlate with unbound fatty acid concentrations. The mean phenytoin unbound fraction was 10.1% and 8.9% for the ICU and convalescent patients with brain injuries, respectively, and was 7.0% for the healthy volunteers. CONCLUSIONS: Phenytoin protein binding was significantly correlated with albumin and was more variable in ICU and convalescent patients with brain injuries than in healthy volunteers. The high dosage requirements and subtherapeutic unbound phenytoin concentrations observed during acute care are best explained by increased metabolism. Phenytoin dosage requirements decreased during convalescence.

Chemical Compatibility of Regional Anesthetic Drug Combinations

OBJECTIVE: To define the physical and chemical compatibilities of several classes of drugs that may be used in combination for peridural anesthesia. DESIGN: Morphine, fentanyl, bupivacaine, lidocaine, tetracaine, ketamine, and clonidine were admixed for one hour in five groups of three-drug combinations, plus one group of all seven drugs. The combinations were inspected macroscopically and microscopically to determine physical compatibility. The admixtures were evaluated by gas chromatography/mass spectroscopy (GC/MS) and compared with known standards to determine chemical compatibility. RESULTS: The admixtures showed no physical incompatibility on microscopic or macroscopic evaluation. Chemical compatibility of all mixtures was confirmed by GC/MS. Ion chromatograms of the drugs in admixtures were identical to previously established standards. CONCLUSIONS: The agents evaluated demonstrated physical and chemical compatibility under conditions that would be observed during the administration of peridural anesthesia. Combinations of these drugs therefore could be safely admixed for use in anesthesia.

Secondary hyperalgesia is not affected by wound infiltration with bupivacaine

The purpose of this study was to determine the effects of wound infiltration with bupivacaine on incisional pain and the zone of secondary hyperalgesia. Twenty-eight healthy parturients were studied in a double-blind randomized trial. At the time of Caesarean section one wound edge was infiltrated with saline 0.9% and the other with bupivacaine 0.25%. After 24 hr, visual analogue scores were obtained for incisional pain and the zone of secondary pain around the incision was measured. Patients served as their own controls. Visual analogue scores for the bupivacaine side of the wound were less than for the saline side (P < 0.05). The zone of secondary pain was similar overall for both sides of the wound. It is concluded that the bupivacaine-infiltrated side of the wound was less painful than the saline-injected side 24 hr postoperatively. The zone of pain measured around the wound edges was unaffected by bupivacaine or saline.RésuméCette étude vise à évaluer l’efficacité de l’infiltration locale de bupivacaine sur la douleur de l’incision et la zone d’hyperalgie secondaire périphérique. Vingt-huit parturientes en bonne santé font partie de cette étude randomisée et à double insu. Au moment de la césarienne, une lèvre de la plaie est infiltrée avec du soluté physiologique 0,9% et l’autre avec de la bupivacaïne 0,25% Après 24 heures, on évalue sur une échelle visualle analogue la douleur de l’incision et la zone d’hyperalgie secondaire périphérique, les patientes étant leurs propres contrôles. Les scores de l’échelle visuelle analogue pour le côté bupivacaine de la plaie sont plus bas que ceux du côté soluté physiologique (P < 0,05). La zone d’hyperalgie secondaire est la même sur les deux côtés de la plaie. En conclusion, à la période postopératoire, le côté de la plaie infiltré avec la bupivacaine est moins douloureux que le côté infiltré avec du physiologique. La zone de douleur mesurée en périphérie de la plaie n’est affectée ni par la bupivacaine, ni par le physiologique.

Neurotoxicity of lidocaine combined with mexiletine.

atients with cardiac disease and ventricular dysrhythmias often receive a combination of P antiarrhythmic medications. Drugs most commonly used for suppression of both ventricular and supraventricular arrhythmias are Class I-A antiarrhythmic drugs, such as quinidine, procainamide or disopyramide. Class I-B antiarrhythmic drugs, which include lidocaine, tocainide, or mexiletine, are irtdicated for treatment of symptomatic ventricular arrhythmias, including frequent unifocal or multifocal premature ventricular contractions, couplets, and tentricular tachycardia (VT) (1). All Class I-B drugs are structurally similar but differ in their pharmacokinetic properties (Table 1). Both Class I-A and I-B drugs have central nervous system (CNS) toxicity. Adverse r eurologic sequelae represent the most common of the toxic effects observed with lidocaine and its der ivatives (2). A combination of antiarrhythmic drugs may be administered when monotherapy is unsuccessful in controlling dysrhythmias. Several reports have suggested that combination therapy increased the efficacy of the drugs used to suppress ventricular dysrhythniias (3-5). There are no data that describe the effects of the combined therapeutic use of intravenous (IV) 1 [docaine with oral mexiletine. We describe a case of neurotoxicity occurring as a direct result of concurrent use of these drugs.