General anesthesia for whole-body hyperthermia.

General anesthesia was used to facilitate 259 whole-body hyperthermia treatments in 90 patients. These patients fell into American Society of Anesthesiologists Classifications 3 (moderate to severe systemic disease) and 4 (severe systemic disease with life-threatening potential). Whole-body hyperthermia imposes severe stress on cardiopulmonary and renal function. In this series, elevation of temperature from 38 degrees to 41.5 degrees raised cardiac output to approximately 200% of control, while oxygen consumption rose 35%. General anesthesia provides conditions which allow for more precise control and support of vital signs, fluid requirements, and blood gases.

Outcome of adult cardiopulmonary resuscitations at a tertiary referral center including results of "limited" resuscitations.

BACKGROUND: The results of in-hospital resuscitations may depend on a variety of factors related to the patient, the environment, and the extent of resuscitation efforts. We studied these factors in a large tertiary referral hospital with a dedicated certified resuscitation team responding to all cardiac arrests. METHODS: Statistical analysis of 445 prospectively recorded resuscitation records of patients who experienced cardiac arrest and received advanced cardiac life support resuscitation. We also report the outcomes of an additional 37 patients who received limited resuscitation efforts because of advance directives prohibiting tracheal intubation, chest compressions, or both. MAIN OUTCOME MEASURES: Survival immediately after resuscitation, at 24 hours, at 48 hours, and until hospital discharge. RESULTS: Overall, 104 (23%) of 445 patients who received full advanced cardiac life support survived to hospital discharge. Survival was highest for patients with primary cardiac disease (30%), followed by those with infectious diseases (15%), with only 8% of patients with end-stage diseases surviving to hospital discharge. Neither sex nor age affected survival. Longer resuscitations, increased epinephrine and atropine administration, multiple defibrillations, and multiple arrhythmias were all associated with poor survival. Patients who experienced arrests on a nursing unit or intensive care unit had better survival rates than those in other hospital locations. Survival for witnessed arrests (25%) was significantly better than for nonwitnessed arrests (7%) (P =.005). There was a disproportionately high incidence of nonwitnessed arrests during the night (12 AM to 6 AM) in unmonitored beds, resulting in uniformly poor survival to hospital discharge (0%). None of the patients whose advance directives limited resuscitation survived. CONCLUSIONS: Very ill patients in unmonitored beds are at increased risk for a nonwitnessed cardiac arrest and poor resuscitation outcome during the night. Closer vigilance of these patients at night is warranted. The outcome of limited resuscitation efforts is very poor.

Endotracheal tube and tracheobronchial obstruction as causes of hypoventilation with high inspiratory pressures.

Two cases of difficult ventilation are presented, the first caused by endotracheal tube obstruction with nasal turbinate, and the second caused by tracheobronchial obstruction with blood clots. The clinical presentation in each case was characterized by extreme difficulty in ventilating and severe hypercapnia despite vigorous ventilatory efforts with either a mechanical ventilator or resuscitator bag. A simple manipulation of the endotracheal tube cuff helped to differentiate between increased impedance caused by endotracheal tube obstruction as opposed to increased respiratory system impedance beyond the tip of tube. In the second patient, in whom even a short interruption of ventilation was poorly tolerated, simultaneous rigid bronchoscopy (for removal of intratracheal masses) and ventilation via endotracheal tube were successfully performed.

Treatment of a bronchopleural fistula with a Fogarty catheter and oxidized regenerated cellulose (surgicel).

A patient with bronchopleural fistula was successfully treated by occluding the fistula with an inflated Fogarty catheter balloon packed with oxidized regenerated cellulose (Surgicel) using a fiberoptic bronchoscope. After 48 h, the balloon was deflated, the fistula had sealed, and the patient did well. This simple and relatively noninvasive therapy was effective in this patient who was not a surgical candidate.

Dextroamphetamine with morphine: respiratory effects.

The combination of dextroamphetamine and morphine has been shown to be synergistic for analgesia and antagonistic for most other effects. However, the claim that dextroamphetamine antagonizes the respiratory depression caused by morphine has not been well substantiated. In this double-blind study, we investigated respiratory effects, including resting respiration, isohypercapnic ventilation, CO2 response, dose response, and duration of these effects with dextroamphetamine alone and in combination with morphine. Dextroamphetamine alone (0.215 mg/kg) caused increases in minute ventilation and a leftward shift of the CO2 response curve that lasted for less than 2 hours. Dextroamphetamine combined with low-dose morphine (0.15 mg/kg) antagonized respiratory depression throughout the 5-hour observation period. Dextroamphetamine combined with high-dose morphine (0.30 mg/kg) was unable to completely antagonize depressed ventilation, and some residual effects of morphine persisted at 23 hours.

Improved postoperative analgesia with morphine added to axillary block solution.

STUDY OBJECTIVE: To determine whether the addition of morphine to the axillary block local anesthetic solution provides improved or prolonged postoperative analgesia. DESIGN: Prospective, randomized, double-blind clinical trial with 24-hour follow-up. SETTING: Ambulatory unit of a large academic referral center. PATIENTS: Consecutive healthy volunteers scheduled for elective upper extremity surgery. INTERVENTIONS: Patients in the treatment group (AX) were given intravenous (IV) saline and had morphine 0.1 mg/kg added to their axillary block solution. Control subjects (CT) received morphine 0.1 mg/kg IV and had saline added to their axillary block solution. All axillary blocks were performed using 0.55 ml/kg of 1.5% lidocaine with epinephrine 1:200,000. MEASUREMENTS AND MAIN RESULTS: During the first 24 hours after surgery, visual analog scale (VAS) scores, supplementary analgesic (oxycodone 5 mg with acetaminophen 500 mg) use, and complications were recorded. Both groups had similar VAS scores throughout the study. In the 24-hour postoperative study period, AX patients required approximately half as many doses (median, 2 doses; range, 0 to 7 doses of supplemental analgesic as CT patients (median, 4 doses; range, 0 to 12 doses). There were no major complications in either group. CONCLUSIONS: The addition of morphine 0.1 mg/kg to the local anesthetic axillary block solution provided improved postoperative analgesia without an increased frequency of side effects or major complications.

Epidural opioids during laminectomy surgery for postoperative pain.

STUDY OBJECTIVE: To determine whether morphine applied directly to the dura during laminectomy surgery provides superior postoperative analgesia during the first 24 hours. DESIGN: Randomized, double-blind study. SETTING: A university-affiliated hospital. PATIENTS: Twenty ASA physical status I and II patients ages 18 to 60 years. INTERVENTIONS: Simultaneous topical dural application and intramuscular (IM) injection of unknown solutions of saline and morphine 3 mg. MEASUREMENTS AND MAIN RESULTS: Postoperative analgesia was assessed using the visual analog scale (VAS), a modified McGill-Melzack pain questionnaire, subjective nursing evaluations, and the amount of supplemental analgesic medication used. Patients were observed for complications and side effects. Compared with the patients who received epidural saline and IM morphine, the patients who received epidural morphine and IM saline had less postoperative pain as determined by VAS scores, nursing evaluations, and amount of supplemental opioid analgesic doses (1.6 +/- 1.2 vs. 4.1 +/- 1.2 analgesic doses per patient; p less than 0.05) required in the first 24 hours. Minor side effects were similar for the two groups. No patient developed respiratory depression. CONCLUSIONS: Morphine 3 mg applied topically to the dura at the end of laminectomy surgery is a simple, safe, and effective way of providing improved postoperative analgesia.

Penetrating eye injury in war.

The percentage of penetrating eye injuries in war has increased significantly in this century compared with the total number of combat injuries. With the increasing use of fragmentation weapons and possibly laser weapons on the battle-field in the future, the rate of eye injuries may exceed the 13% of the total military injuries found in Operations Desert Storm/Shield. During the Iran-Iraq War (1980-1988), eye injuries revealed that retained foreign bodies and posterior segment injuries have an improved prognosis in future military ophthalmic surgery as a result of modern diagnostic and treatment modalities. Compared with the increasing penetrating eye injuries on the battlefield, advances in ophthalmic surgery are insignificant. Eye armor, such as visors that flip up and down and protect the eyes from laser injury, needs to be developed. Similar eye protection is being developed in civilian sportswear. Penetrating eye injury in the civilian sector is becoming much closer to the military model and is now comparable for several reasons.

Respiratory effects of regional anesthesia during acute pain.

BACKGROUND AND OBJECTIVES: It is commonly thought that pain stimulates respiration. The goal of this study was to determine any effect on ventilation caused by acute pain in patients with upper extremity injuries by measuring CO2-response curves before and after regional anesthesia. METHODS: Four patient volunteers refrained from taking analgesic medications during the study period. Visual analogue scale (VAS) pain scores (10 cm scale), resting ventilation and P(ET)CO2, and steady-state, CO2-response curves (4% and 7% inspired CO2) were determined just before and after axillary block anesthesia. RESULTS: Axillary block anesthesia reduced VAS pain scores from 7.1 +/- 1.1 to 0.7 +/- 0.5 (p < 0.05). Resting ventilation and P(ET)CO2 were unchanged. CO2-response curve slopes decreased from 1.84 +/- 0.54 to 1.40 +/- 0.58 l/min-1.mm Hg-1 (p < 0.05), and the curves were displaced 3.2 +/- 1.2 mm Hg to the right at 25 l/min-1 VE (p < 0.05). CONCLUSIONS: Other causes for the respiratory changes observed are discussed. It is concluded that acute pain stimulates respiration as measured by the steady-state, CO2-response method and that relief of acute pain results in a decrease in CO2-mediated ventilatory drive. More research is needed using both experimental pain models and patients with chronic pain.

Effects of succinylcholine on respiratory and nonrespiratory muscle strength in humans.

Succinylcholine was administered to 10 healthy unanesthetized volunteers to assess its effect on respiratory and nonrespiratory muscle strength and the ventilatory response to CO2. Iso hypercapnia with PETCO2 8-10 mmHg above control was maintained throughout the study, succinylcholine infusion rates were increased from 20 micrograms X kg-1 X min-1 until grip strength (GS) was 20% of control. CO2-stimulated ventilation was 16.1 +/- 1.8 l/min (mean +/- SD), approximately three times control, and remained at that level throughout the study because of nonsignificant decreases in tidal volume and increases in respiratory frequency. Respiratory strength, as measured by maximum inspiratory pressure (IP), maximum expiratory pressure (EP), and forced vital capacity (FVC), was spared relative to GS. When GS = 50% of control, IP = 86 +/- 8% of control, EP = 78 +/- 15%, and FVC = 86 +/- 9%. Wide variation occurred from subject to subject in the succinylcholine versus GS dose-response curve position. However, in all subjects the slope of the dose-response curve was very steep.

Modification of the phenotypic expression of murine dystrophy: a morphological study.

The extensor digitorum longus muscles of 4-6-week-old normal mice (129 ReJ) and dystrophic mice (129 ReJ dy/dy) were orthotopically transplanted. Grafted muscles were examined 1, 3, 7, 14, 20, 50, and 100 days post-transplantation. The myofibers of both types of grafts underwent a similar time course of necrosis and regeneration. Other than during the initial necrotic response, no evidence of necrotic myofibers was found in either type of grafted muscle. At 100 days post-transplantation, the grafted normal and dystrophic muscles were essentially similar, except that the dystrophic graft was of smaller size. Based on a comparison of the number of myofibers found at the 100-day grafts' widest girths [631 +/- 59 SEM, for normal grafts (Bourke and Ontell, 1984); 631 +/- 74 SEM, for dystrophic grafts], it is suggested that the regenerative capability of traumatized 4-6-week-old dystrophic muscle is similar to that of traumatized normal muscle. At 100 days post-transplantation, the grafted dystrophic muscle appeared "healthier" than untraumatized muscle from age-matched dystrophic mice, having less variation in myofiber diameter, better fascicular organization, and less connective tissue. The transplantation system demonstrates the possibility of modifying the expression of genetic programming of myopathic disorders using environmental manipulation.

The steady-state and rebreathing methods compared during morphine administration in humans.

1. We examined the quantitative and qualitative differences between the steady-state and rebreathing methods of determining CO2-response curves before and after each of two doses of intravenous morphine (0.07 and 0.14 mg kg-1) in four healthy male humans. 2. During each study session steady-state and rebreathing CO2-response curves were determined as an ordered pair (separated by 15 min). Carbon dioxide-response curves were determined for control, after 0.07 mg kg-1 morphine, and after a total of 0.21 mg kg-1 morphine. Each subject was studied on a second occasion when the order of the CO2-response pairing was reversed. 3. The results are discussed and related to a model that may account for the differences based on the step increase in CO2 at the onset of rebreathing, the rate of rise of CO2 during rebreathing and the time constant for the central chemoreflex. 4. Our empirical conclusion is that morphine causes a parallel right shift of the steady-state CO2-response curve and causes a non-specific decrease in the slope of the rebreathing CO2-response curve. We suggest that the parallel shift of the steady-state CO2-response curve is specific to drugs acting on opioid receptors.

Branched myofibers in long-term whole muscle transplants: a quantitative study.

Orthotopic transplants of whole extensor digitorum longus muscles were performed on six 4-6-week-old 129 ReJ mice. One hundred days posttransplantation, the animals were killed and the regenerated muscles were processed for electron microscopy. The grafts contained polygonal-shaped myofibers with persistent central nuclei, organized into discrete muscle fascicles. No central area of fatty infiltration or fibrosis was observed. The mean number of myofibers in a regenerating transplanted muscle, as determined from an ultrathin section taken from the graft's widest girth, was 631 (SEM = +/- 59), a reduction of approximately 32% from that found in age-matched control muscle (Ontell et al., 1983). By following the myofibers in spaced, serial ultrathin sections along their length, it was found that the branched, regenerating myofibers found in immature grafts of normal muscle (Ontell et al., 1982) persisted in stabilized, long-term transplanted muscle. The frequency of branching was determined by following each fiber found at the widest girths of four of the grafts in spaced, serial ultrathin sections (15-micron intervals) for approximately 2% of the total length of the grafts. Over this distance, 6.6% of the fibers were involved in the branching phenomenon. The persistence of branched fibers in long-term grafts and the frequency with which the branching phenomenon was found to occur may have physiological consequences and should be investigated.

Respiratory interactions of ketamine and morphine.

Six healthy, consenting volunteer males received ketamine iv in five logarithmically scaled doses totaling 3 mg/kg on three occasions each. The sessions differed only in the initial injection of an unknown drug: placebo, morphine sulfate 0.2 mg/kg, or morphine sulfate 0.4 mg/kg. Initial and terminal steady-state ventilatory responses to CO2 (VERCO2) and isohypercapnic ventilation (end-tidal CO2 49.8 +/- 2.4 mmHg) during drug administration assessed CO2-mediated ventilatory drive. Oxygen concentration of 40% ablated hypoxic drive contribution. Morphine caused a decrease of isohypercapnic ventilation (VE) of 8.2 +/- 1.2 l/min after 0.2 mg/kg. Doubling the dose to 0.4 mg/kg gave a further depression of 6.6 +/- 1.8 l/min. No subject lost consciouness after morphine. Over a dose range of 0.39 to 3.0 mg/kg ketamine caused log-linear dose-related depression of 1.6 +/- 0.3 l/min for each doubling of dose, although the first significant depression of 4.9 +/- 1.1 l/min did not occur until the third dose (1.1 mg/kg) in the absence of morphine. All subjects were unconscious after 1.8 mg/kg ketamine. Slopes of the VERCO2 did not differ from control, regardless of the pretreatment, placebo, or morphine in the two doses. Ketamine alone, 3.0 mg/kg, caused a displacement of VERCO2 of +2.0 +/- 1.2 mmHg in CO2, while combination of ketamine and morphine in either dose caused a +10 mmHg displacement of VERCO2. Thus, ketamine appears qualitatively similar but less potent than premedicant doses of morphine in depressing respiration despite near equipotency in producing loss of consciousness.

Evaluation of the premature infant at risk for postoperative complications.

We reviewed anaesthetic records of 35 infants with a history of prematurity, who presented for elective herniorrhaphy. We applied a scoring system to help evaluate risk of postoperative complications. Six patients experienced postoperative complications. All six patients had a score of five or more and gave history of either apnoea or a history of moderate bronchopulmonary dysplasia. A preoperative history of apnoea and/or moderate bronchopulmonary dysplasia appear to be valuable markers for postoperative complications. A conceptual age of 40 weeks is an acceptable lower limit of age providing there is no history of apnoea or pulmonary disease.