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Methods: In a double-blind study, we compared the efficacy of a combination of sustained-release acetazolamide and low-dose dexamethasone and acetazolamide alone for prophylaxis against acute mountain sickness (AMS) caused by rapid ascent to high altitude. Before ascent, 13 subjects were randomly assigned to receive a combination of one sustained-release acetazolamide capsule (500 mg) in the afternoon and 4 mg dexamethasone every 12 h, or a combination of the same dose of acetazolamide once daily and a placebo every 12 h. Days 1 and 2 were spent at 3698 m (La Paz, Bolivia), while days 3 and 4 were spent at 5334 m (Mount Chaclataya, Bolivia). Ascent was by 2 h motor vehicle ride. Heart rates, peripheral oxygen saturations and a modified score derived from the Environmental Symptom Questionnaire (modified-ESQ) were measured on each day. In addition, weighted averages of the cerebral (AMS-C) and respiratory (AMS-R) symptoms were calculated for days 3 and 4., Results: Heart rate and modified-ESQ scores increased on days 3 and 4 compared with the other days in the acetazolamide/placebo group only (p < 0.05). Oxygen saturations decreased in both groups on days 3 and 4 (p < 0.05), but the decrease was greater in the acetazolamide/placebo group (p < 0.05). AMS-C and AMS-R scores rose above the suggested thresholds for indication of AMS on days 3 and 4 in the acetazolamide/placebo group only (p < 0.05)., Conclusion: We conclude that this combination of sustained-release acetazolamide once daily and low-dose dexamethasone twice daily is more effective in ameliorating the symptoms of AMS than azetazolamide alone at the ascent that was studied.

We compared the performance deficiencies of airway management captured by three types of self-reports with those identified through video analysis. The three types of self-reports were the anesthesia record (a patient record constructed during the course of treatment), the anesthesia quality assurance (AQA) report (a retrospective report as a part of the trauma center's quality assurance process), and a posttrauma treatment questionnaire (PTQ), which was completed immediately after the case for the purposes of this research. Video analysis of 48 patient encounters identified 28 performance deficiencies related to airway management in 11 cases (23%). The performance deficiencies took the form of task omissions or practices that lessened the margin of patient safety. In comparison, AQA reports identified none of these performance deficiencies, the anesthesia records identified 2 (of 28), and the PTQs suggested contributory factors and corrective measures for 5 deficiencies. Furthermore, video analysis provided information about the context of and factors contributing to the identified performance deficiencies, such as failures in adherence to standard operating procedures and in communications.

Evidence of violations of the 1949 Geneva Conventions by Iraq's military personnel during Desert Shield and Desert Storm are described and adverse effects on the Kuwaiti health care delivery system are discussed. New diplomatic and military initiatives that include education and accountability are needed to ensure better compliance with international conventions designed to protect victims of war.

Field anesthesia can be practiced safely and effectively but requires special training to acquire familiarity with the techniques. Because field anesthesia may be required even in sophisticated countries for entrapment situations, skill should be maintained by practicing the appropriate techniques on a regular basis. Field anesthetic techniques are not second rate methods; they are just different. Although improvisation in the disaster situation has merit, it is not the place for experimenting with new and untried techniques.

Proper care of the severely injured patient will require the development of a new anesthesia specialist. The trauma anesthesiologist, like the cardiovascular anesthesiologist, must become thoroughly familiar with one disease. The anesthesiologist who manages patients with traumatic disease must become an expert in critical care, high-risk anesthesia practice, and emergency resuscitation of the trauma patient. An outline for a fellowship in trauma anesthesia and critical care is included.

The five components integral to modern, sophisticated airway management in trauma patients include equipment, pharmacologic adjuncts, manual techniques, physical circumstances, and patient profile. Although there is a finite number of pieces and types of equipment, pharmacologic adjuncts, and manual techniques, the last two components are variable. For purposes of brevity and clarity, this article has presented definitive airway management in terms of a well-organized, fully-equipped admitting (resuscitation) area of a trauma center, but a trauma patient may require airway management in a variety of physical circumstances, including the field, the transport vehicle, and numerous locations within the trauma center. We believe that the commonly used airway management algorithms are a poor substitute for a conceptual understanding of the basic principles of the five components of airway management, although these decision trees may be useful as learning tools. The construction of a truly complete decision tree is virtually impossible because of the high number of individual patient profiles.

From peripheral nerve blocks to central neuraxis blocks, regional anesthesia offers a wide range of options for the comprehensive management of trauma victims. Experience during wars and with mass casualties has proven the safety and efficiency of regional techniques. In this article, authors review the merit of these techniques to advance the quality of patient care. They also suggest the need to improve the selection of techniques, ranging from the prehospital phase to long-term rehabilitation.

The tracheas of 12 patients, intubated from 2 hours to 20 days with tracheal airways equipped with the newer style, high-volume, low-pressure (HVLP) cuffs, were examined at autopsy. The type and severity of iatrogenic damage to the epithelium and submucosa was determined and compared to that seen in a previous study of 54 patients, who had been intubated with the older-style low-volume, high-pressure (LVHP) cuffed airways. The tracheal epithelial and submucosal damage due to intubation with the HVLP cuffed airways was considerably less than that with LVHP cuffs. The submucosal glands were often spared, and some of the tracheal epithelium even survived 20 days of exposure to the "soft" cuffs. However, the pseudostratified ciliated epithelium, which normally lines the trachea, was often replaced by stratified squamous epithelium. If such a zone of nonciliated epithelium remains in the trachea of a long-term survivor, its detrimental effect on the removal of particulate matter from the tracheobronchial tree may have to be considered.

Restoration of adequate spontaneous circulation after "arrest" and cardiopulmonary resuscitation (CPR) of 546 patients before and 460 patients after initiation of a CPR training course in a 500-bed city hospital is reported. Between January 1972 and June 1976, adequate circulation after CPR was present in 38.6% of patients before and 50.4% after training ICU nurses and house physicians in modern resuscitation techniques. Factors crucial to resumption of adequate circulation are: (1) CPR training of all hospital personnel so that effective CPR can be started immediately after recognition of an arrest situation, (2) production of a palpable pulse with closed chest cardiac massage, and (3) prompt effective therapy so that the time interval between arrest and resumption of adequate spontaneous circulation is short.

Prior intermittent exposure to 40 percent O2 protected rats against fatal O2 toxicity. Protection was not absolute, however, for the death of most rats in 100 percent O2 was not prevented but delayed considerably. Furthermore, those rats which did survive exposure to 100 percent O2 for long periods by virtue of prior-adaptation to increased O2 concentrations had pathologic changes in the lungs typical of chronic O2 toxicity. The very early demise of some rats indicated that 1 of 12 animals is hypersenstiive to high concentrations of inspired O2.

The somatosensory evoked potential can be obtained in the anesthetized patient during corrective surgery on the spine. The techniques of anesthesia and somatosensory evoked potential recordings described herein were utilized in fifty-five patients during surgical correction of scoliosis with Harrington instrumentation and spine fusion. No detectable complications were encountered and no neurological morbidity ensued in our series. This method may prove to be of significant value when potential injury to the spinal cord may be encountered during correction of spinal deformities.

Physical characteristics and time-related volume changes in air-inflated tracheal tube cuffs exposed to nitrous oxide were measured in an environmental chamber. Cuff wall diameter, thickness, residual volume, and length were also measured. Gas volumes in most air-inflated tracheal tube cuffs increased 1.7 to 7 ml within 30 min of exposure to pure nitrous oxide. Diffusion rates into most cuffs varied inversely with cuff thickness and directly with the partial pressure of nitrous oxide. There were significant differences in diffusion rates among cuffs of the same composition with different densities or porosities as well as among cuffs of different compositions. Cuff diameters ranged from 13.8 to 32 mm; thicknesses from .033 to .55 mm; residual volumes from .22 to 19.4 ml; lengths from 23.1 to 49.1 mm. Intracuff volume and pressure increase related to gas diffusion into air-inflated cuffs should be periodically adjusted or pressure automatically controlled during nitrous oxide anesthesia. Large-diameter, thin-walled cuffs are recommended.

This study compares physical and behavioral characteristics of currently used cuffed tracheal tubes. Variability in physical and behavioral characteristics between size 8 tracheal tubes and cuffs exists: radius of tube curvature varies from 12.1 to 15.8 cm, bevel angle 39 to 56 degrees, bevel direction 73 to 107 degrees, distance from proximal end of bevel to cuff 15.4 to 24.4 mm, internal tube diameter 7.5 to 8.8 mm, wall thickness 1.14 to 2.37 mm, force to collapse 1020 to 3103 g, angle to kink 52 to 96 degrees, and indentation hardness 65.4 to 83.1. Cuff lengths vary from 29.7 to 45.3 mm, thickness 0.03 to 0.54 mm, diameter 14.5 to 32 mm, and cuff resting volume 0.15 to 19.9 ml. We recommend use of a soft, thermolabile, kink- and collapse-resistant tracheal tube fitted with a soft, thin-walled, tough, compliant, moderately long cuff, with a moderately large resting volume and diameter larger than tracheal diameter. Argyle, National Catheter, Ohio, Portex, Rusch "safety," and Shiley tracheal tubes resist collapse and kinking. Argyle, Lanz, National Catheter "hi-lo," National Catheter "intermediate hi-lo," Ohio, and Portex "profile" cuffs are thin and have diameters larger than the average male tracheal diameter.

Effects of long-term inhalation of 100 per cent oxygen on the microbial flora of the rat larynx, trachea, and large intestine were studies. Rats were kept 14 days in an atmosphere of 100 per cent oxygen after being conditioned to high oxygen concentrations by exposure to three cycles of 100 per cent oxygen (two days) alternating with 40 percent oxygen (two days). Controls were kept under similar conditions in normal atmosphere. Rats were sacrificed, and at necropsy laryngotracheal swabs and fecal material from the large intestine were obtained and cultured for bacteria and fungi. Streptobacillus moniliformis, the predominant microorganism in the upper tracheas of controls, was not isolated from the oxygen-treated rats. Alpha-hemolytic streptococcus and Staphylococcus albus were present in control rats, but were found less frequently in rats exposed to oxygen. Pseudomonas and Proteus, infrequently isolated from controls, were predominant and sometimes the only microorganisms isolated from oxygen-treated rats. The data indicate that prolonged exposure of the rat to 100 per cent oxygen shifts the microbial flora in the upper respiratory tract from mainly gram-positive to mainly gram-negative bacteria. In contrast, there was no significant difference between the microbial flora in large intestines of control and oxygen-treated rats. The possibility that similar changes may occur in man should be considered when prolonged oxygen therapy is contemplated.

Transconjunctival oxygen tension (PcjO2) was studied using a hypobaric chamber and during mountaineering excursions. Measurements obtained during acute chamber exposures (15-20 min) at sea level, 1829 m (6,000 ft), 3048 m (10,000 ft), 4267 m (14,000 ft) and return to sea level were (means +/- SEM): 60.1 +/- 2.7, 49.1 +/- 1.8, 38.3 +/- 2.4, 27.4 +/- 1.5, and 61.1 +/- 2.8 mm Hg, respectively (n = 13). The ratio of PcjO2 to arterial blood oxygen tension (PaO2) did not change in a consistent manner between sea level and 4267 m; PcjO2 was 74 +/- 6.9% of PaO2. The 16 subjects participating in the mountaineering phase of the study revealed similar means at sea level and 1829 m (57.4 +/- 2.4 and 46.3 +/- 1.9 mm Hg respectively), but a smaller decrement was observed at 3048 m (43.0 +/- 1.6 mm Hg). The difference between mountain and chamber values may be accounted for by a partial acclimatization to altitude brought about by longer exposure on the mountain excursions. A comparison between PcjO2 and transcutaneous oxygen tension during the chamber study suggests that a greater precision and sensitivity is obtained with measurement of oxygen tension at the conjunctival site. PcjO2 measurement is a non-invasive reflection of PaO2 which is suitable for continuous monitoring during hypoxia studies.

The following study was undertaken to study the effects of multiple stressors on the pituitary-testicular axis in men. We examined the endocrine responses of 16 healthy young men participating in a mountain training exercise. Blood was drawn at 1830 m just before ascent (t = 0 h), after an overnight rest at 3050 m (t = 24 h), and immediately after a descent from 3050 m in adverse conditions (t = 48 h). Plasma E2 increased significantly through the study periods (medians: 74, 104, 164 pmol/l at t = 0, 24, 48 h) while 17 alpha-hydroxyprogesterone progressively decreased. Testosterone and the bioactive LH to immunoreactive LH ratio decreased only at 48 h. There were no changes observed for plasma cortisol, prolactin or thyroxine. The observed rise in E2 may be due to one or more stressors associated with altitude, including hypoxia and increased solar radiation. This data suggests a role for E2 in the secondary testosterone decrease.

This study compared intracuff pressure (ICP) during mechanical ventilation in a variety of currently used endotracheal (ET) and tracheostomy (trach) tube cuffs and related cuff physical characteristics. Tracheostomy tube physical characteristics were also measured. Variation was observed to exist between "just-seal" inspiratory and end-expiratory intracuff pressure during mechanical ventilation. Cuff diameter, thickness, compliance, geometry (shape), resting volume, and just-seal volume also varied. ICP varied with cuff diameter, thickness, compliance, geometry (shape), and trachea size, as well as tube curve and cuff position in the trachea. Thin, large-diameter, compliant cuffs generally "just seal" with relatively low ICPs. We recommend use of tracheal airways (endotracheal and tracheostomy) fitted with cuffs that seal in patients with low intracuff pressures. We also recommend nonrigid (soft) thermolabile tracheostomy tubes.