Strategies to prevent organ failure.

The gastrointestinal tract and the generalized inflammatory response initiated by severe injury or infection have been implicated in the pathophysiology of multiple-organ system failure. Once multiple-organ system failure has occurred, treatment focuses on supporting end-organ function. Recent studies have shown, however, that it may be possible to reduce the incidence and prevalence of multiple-organ system failure by controlling the reperfusion injury cascade, normalizing gastrointestinal blood flow and preserving the integrity of the gastrointestinal immune barrier.

Failure of splanchnic resuscitation in the acutely injured trauma patient correlates with multiple organ system failure and length of stay in the ICU.

INTRODUCTION: The purpose of our study was to evaluate the relationship between the state of splanchnic perfusion and morbidity and mortality in the hemodynamically unstable trauma patient acutely resuscitated in the ICU. METHODS: Gastric intramucosal pH (pHi) was monitored in a blinded fashion in 19 consecutive critically ill trauma patients with evidence of systemic hypoperfusion (arterial pH [pHa] <7.35, base excess >2.3 mmol/L, lactic acid >2.3 mEq/L) who received right heart catheters to guide resuscitation and subsequent hemodynamic monitoring. DESIGN: Prospective randomized consecutive series with retrospective analysis of data. SETTING: University hospital, surgical ICU. RESULTS: The mean values of APACHE II (acute physiology and chronic health evaluation) Injury Severity Score, pHa, arterial base excess, cardiac index, oxygen delivery index, and oxygen consumption index by 24 h were similar (Student's t test, p>0.1) between survivors and nonsurvivors and between those who developed at most a single (SOF) vs multiple organ system failure (MOSF). Supranormal oxygen delivery and utilization parameters were evenly distributed among survivors and nonsurvivors and patients with SOF and MOSF (chi2, p>0.5). Ten patients had a pHi <7.32 and nine patients had a pHi > or = 7.32 by 24 h. Fifty percent of patients with a pHi <7.32 died, compared with 11% of patients with a pH > or = 7.32 (chi2, p=0.07). Sixty percent of patients with a pHi <7.32 developed MOSF compared with 11% of patients with a pHi > or = 7.32 (chi2, p=0.03). The one patient who developed MOSF and died in the pHi > or = 7.32 cohort suffered from massive head trauma and had all futile medical interventions halted. No other patients who achieved a pH > or = 7.32 by hour 24 developed MOSF. Survivors with a pHi <7.32 at hour 24 had an increased ICU stay (pHi <7.32=46+/-15 days, pHi > or = 7.32=13+/-9 days; p<0.01). A pHi <7.32 carried a relative risk of 4.5 for death and 5.4 for the occurrence of MOSF. CONCLUSION: Attainment of a pHi > or = 7.32 at hour 24 carried a significantly reduced likelihood of MOSF. Being an inference of the state of regional perfusion, in a high-risk microvascular bed, gastric intraluminal tonometry should identify perfusion states of compensated or uncompensated shock during hemodynamic resuscitation of the critically ill injury patient. A low pHi appears to be a marker of postresuscitative morbidity and subsequent increased length of stay.

The impact of antioxidant and splanchnic-directed therapy on persistent uncorrected gastric mucosal pH in the critically injured trauma patient.

BACKGROUND: Critically ill trauma patients with gastric intramucosal acidosis, as measured by gastric tonometry, have an increased incidence of multiple organ dysfunction syndrome despite supranormal O2 delivery. We altered our resuscitation protocol to maximize splanchnic blood flow and decrease oxygen-derived free radical damage. DESIGN: Prospective clinical trial with historical controls. METHODS: The protocol differed from control by including administration of folate, mannitol, and low-dose isoproterenol. All patients had gastric tonometers and pulmonary artery catheters. If the intramucosal pH (pHi) was less than 7.25, splanchnic-sparing inotropic and vasodilatory agents were used to optimize systemic cardiac output. Two groups of trauma patients with persistent intramucosal acidosis at 24 hours (pHi < 7.25) were compared: a control group (n = 7), and patients who received the splanchnic/antioxidant protocol (n = 13). RESULTS: The two groups were similar based on Acute Physiology and Chronic Health Evaluation II score, Injury Severity Score, age, cardiac index, oxygen delivery, and oxygen consumption. The "splanchnic therapy" group had fewer organ system failures as well as shortened length of intensive care unit and hospital stay. Three of 7 patients in the control group and 2 of 13 patients in the splanchnic therapy group had a final pHi < 7.25. CONCLUSION: Gastric tonometry-guided resuscitation and antioxidant/splanchnic therapy in critically ill trauma patients with persistent gastric mucosal acidosis may decrease multiple organ dysfunction syndrome.

Management of paroxysmal atrioventricular nodal reentrant tachycardia in the critically ill surgical patient.

OBJECTIVES: Paroxysmal atrioventricular nodal reentrant tachycardia is an infrequently encountered supraventricular arrhythmia that continues to present difficult management problems in the critically ill surgical patient. The purpose of this study was to evaluate the efficacy of a new treatment algorithm involving the sequential administration of different classes of antiarrhythmic agents until conversion to sinus rhythm was achieved. DESIGN: Nonrandomized, consecutive, protocol-driven descriptive cohort. SETTING: University hospital surgical and trauma intensive care unit (ICU). PATIENTS: During an 11-month period, we prospectively evaluated all hemodynamically stable patients who sustained new-onset atrioventricular nodal reentrant tachycardia. INTERVENTIONS: Vagal maneuver, followed by the rapid, sequential infusion of antiarrhythmic agents (i.e., adenosine, verapamil, and esmolol, respectively) until the arrhythmia was terminated. MEASUREMENTS AND MAIN RESULTS: Twenty-seven patients (4% of all admissions) were evaluated, including 16 trauma patients (injury Severity Score of 20 +/- 8) and 11 general surgical patients (Acute Physiology and Chronic Health Evaluation II score of 17 +/- 7). Time from ICU admission to onset of atrioventricular nodal reentrant tachycardia was 4.5 +/- 5 days (median 2.5). Arrhythmia termination was achieved in all patients within minutes (mean 13 +/- 10 [SD]). Incremental sequential adenosine administration alone, however, was successful in affecting conversion to sinus rhythm in only 44% of initial episodes of atrioventricular nodal reentrant tachycardia (95% confidence interval 21% to 67%). A total of 14 (52%) patients developed 38 relapses of paroxysmal supraventricular tachycardia in the ICU after initial conversion to sinus rhythm. These relapses required additional antiarrhythmic therapy. Adenosine was only effective in 34% of the relapses (95% confidence interval 17% to 53%). Seven (50%) of these 14 patients developed multiple relapses. However, only two patients were receiving suppressive calcium-channel or beta-adrenergic receptor blockade at the time of relapse. CONCLUSIONS: The use of a multiagent algorithm was effective for the initial conversion of new-onset atrioventricular nodal reentrant tachycardia to sinus rhythm in critically ill surgical and trauma patients. This preliminary report suggests that adenosine has marginal efficacy in the critically ill surgical or trauma patient. Given the high frequency of relapses, regardless of the agents used to achieve initial control, suppression therapy for the arrhythmia during the period of maximal cardiovascular stress is essential.

Stab wounds to the back and flank in the hemodynamically stable patient: a decision algorithm based on contrast-enhanced computed tomography with colonic opacification.

PURPOSE: The authors wanted to determine whether contrast-enhanced computed tomography (CE-CT) with colonic opacification is an accurate tool to triage hemodynamically stable victims of stab wounds to the flank and back. PATIENTS AND METHODS: One hundred forty-five consecutive patients were categorized as low-risk ( penetration superficial to the deep fascia) or high-risk (penetration beyond the deep fascia) based on CE-CT findings. RESULTS: There were no significant differences in admission vital signs, Glasgow Coma Scale, or complete blood counts between low- and high-risk groups. None of the 92 low-risk patients required surgery or had sequelae. Six of the 53 high-risk patients underwent surgery, 2 based on initial CE-CT, 4 due to evolving clinical signs. The CE-CT correctly predicted surgical findings in all cases. CONCLUSIONS: Hemodynamically stable patients with stab wounds to the back and/or flank can be successfully triaged based on CE-CT findings. Low-risk patients may be discharged immediately. High-risk patients may have a discharge decision implemented at 24 hours.

Decreasing catheter-related infection and hospital costs by continuous quality improvement.

OBJECTIVES: a) To reduce the rate of catheter-related infection, using improved skin preparation and catheters impregnated with silver sulfadiazine and chlorhexidine; b) to decrease the number of unnecessary guidewire exchanges of existing catheters by substituting suspected catheter-related sepsis for fever alone as an indication to change an indwelling catheter; and c) to decrease the hospital costs associated with guidewire exchanges and new catheter insertions. DESIGN: Sequential, prospective, descriptive studies using a continuous quality management approach. SETTING: A 20-bed trauma intensive care unit at a university teaching hospital. PATIENTS: Patients (n = 147) admitted from July 1 to December 31, 1992 (phase 1); 34 patients admitted in June and September 1993 (phase 2); and 156 patients admitted between January 1 and June 30, 1994 (phase 3). INTERVENTIONS: Phase 1: Proportions of catheter-related infections and catheter-related bacteremia were compared with our prior reported results. Indications for guidewire exchange were analyzed, and the rate of catheter-related infection for each indication was derived. Phase 2: The rate of catheter-related infection was determined for a trial group of triple-lumen catheters impregnated with silver sulfadiazine and chlorhexidine. Phase 3: Four components were altered. Impregnated triple-lumen catheters were used instead of unprotected catheters. Chlorhexidine skin cleanser was substituted for povidone-iodine solution during initial aseptic preparation during catheter insertion and subsequent guidewire exchange. Suspected catheter-related sepsis was substituted for fever as an indication for guidewire exchange. The "safe" period (the time before considering changing a catheter because catheter-related sepsis was suspected) was extended from 2 to 4 days. MEASUREMENTS AND MAIN RESULTS: The overall rate of catheter-related infection in phase 1 was 15% (15% for triple-lumen catheters and 16% for introducers). Catheters changed for site inflammation had a 46% rate of catheter-related infection, significantly higher than for all other indications, including fever (p < .03). The rate of catheter-related infection was significantly (p = .0002) higher for catheters in place for > 10 days compared with lesser durations. Fever was the indication for 42% of all guidewire exchanges. In phase 2, the catheter-related infection rate was 2% (one positive of 48 catheters), significantly (p = .0231) lower than the phase 1 rate. In phase 3, the overall rate of catheter-related infection was 8.6%, significantly (p = .0067) lower than the 15% rate in phase 1. The proportion of protected triple-lumen catheter catheter-related infections decreased significantly (p = .0024) from 15% to 6%. The rate of catheter-related infection for introducers was the same in both phases (p = .33). The days of catheterization for all catheters increased from 4.5 +/- 2.6 to 5.4 +/- 3.6 (p < .0001). The days for triple-lumen catheters increased from 4.7 +/- 2.7 to 7.0 +/- 3.9 (p < .0001). For introducers, there was no difference in the days of catheterization. The proportion of catheters changed for suspected catheter-related sepsis decreased significantly (p < .0001) to 23% from the 42% changed for fever in phase 1. The proportion of catheter-related infections for catheters changed for fever was 18% in phase 1. The proportion of catheter-related infections for catheters changed for suspected catheter-related sepsis was 13% in phase 3 (p = .43). The total number of catheters used per patient in phase 3 was 1.9 +/- 1.4, significantly lower than the 2.6 +/- 2.7 catheters used in phase 1 (p = .0018). The number of triple-lumen catheters decreased from 1.8 +/- 1.2 to 1.0 +/- 1.2 in phase 3 (p = .0001). CONCLUSIONS: Catheters impregnated with silver sulfadiazine and chlorhexidine had a smaller proportion of catheter-related infection compared with unprotected catheters. Fever alone as an indication for guidewire exchange resu

Re-engineering ventilatory support to decrease days and improve resource utilization.

OBJECTIVE: The objective of this study was to describe the development of a cost-effective ventilatory strategy using a portable microprocessor-controlled respiratory monitor (Bicore CP-100; Allied Healthcare Products, Riverside, CA.) SUMMARY BACKGROUND DATA: Until recently, clinicians have had to accept the uncertainties of clinical judgment, which unfortunately, often biased the patient to a prolonged ventilatory course to avoid extubation failures, necessitating reintubation. METHODS: Over a 4-year period, the authors attempted to re-engineer the process of ventilatory support based on measured work of breathing (WOB), including physiologic (WOBPhys), imposed (WOBImp) and total (WOBTot). RESULTS: The authors made 90 determinations of WOB in 31 patients. The coefficient of determination (i2) of WOBTot, with the breathing frequency was 0.35, with tidal volume was 0.10, and with the rapid shallow breathing index (f/V(tau)) was 0.23; therefore, the authors discarded them as reliable inferences. Of 27 patients ventilated for > 2 days with satisfactory blood gases, but with breathing frequency > 30 breaths/minute, 6 had WOBTot < 0.8 J/L and were extubated successfully. In 21 patients, WOBTot was elevated to 1.6 +/- 0.83 J/L, WOBImp was 1.1 +/- 0.64 J/L, approximately twice the WOBPhys (0.5 +/- 0.26 J/L), a normal value. Extubation was successful in 20 of those 21 patients. This approach was extended to the spontaneous breathing pre-extubation trial. In addition, the ventilator was adjusted so that the patient sustained a WOBTot of 0.6 to 1 J/L during the ventilatory support. This evolution was tracked for 18 months in a series of 838 trauma intensive care unit patients. Average duration of ventilation decreased from 8.2 to 4.2 days (49%; p < 0.01). This translated into approximately 2400 decreased ventilator days per year. CONCLUSION: Objective measurement to guide the adequacy of ventilatory support and interpret apparent clinical weaning failures decreased total ventilatory time by 50%, permitting extubation in nearly 20% of patients previously considered failures.

Cost effectiveness in the intensive care unit.

Effective policies to reduce true costs will require integrated information systems and demand behavioral changes from providers. A congenial environment must be created among medical educators, providers, vendors, and consumers if cost reduction is to be accomplished without compromising quality or access to critical care services. Physicians should do everything they believe may be of benefit for their patients, but we have an obligation to educate the public about the limitations of our art and the fact that "doing everything" is not always best for the patient or the grieving family. A significant method of controlling ICU costs is closely monitoring which patients are admitted and when they are discharged. Laboratory tests represent a source of cost reduction, and physicians must learn to order specific tests and not simply a battery of tests which includes the actual test desired. Limits should be placed on the tests that are ordered in terms of number and frequency. Improved efficiency of the utilization of resources should improve the care of our patients. The largest budget item of any or most critical care units is nursing; it is paramount that this essential and invaluable resource be utilized in a cost-effective manner. Diminishing unnecessary activity will both decrease complications and have salutary effects. Having more time to be with patients and their families will decrease our sense of failure and fulfill the important goal of caring. Physicians and nurses can return to thinking, assessing, and decision making instead of frenetically ordering, reacting, and intervening, which, we believe, accurately describes informational overload created by undue emphasis on high technology. In this way, we can respond to Fuch's exhortation that "physicians consider the possibility of contributing more by doing less." In responding, however, we must never forget that the societal, not merely the economic impact of medical care, is our principal consideration. We must first contribute more by achieving a greater understanding of the medical care process. Only then can we know how to do less at the bedside. We can and must distinguish between costly and high-quality care--they are not necessarily synonymous.

Preoperative intensive care unit consultations: accurate and effective.

OBJECTIVES: To determine if a structured preoperative ICU consultation would correctly assign patients to preoperative invasive monitoring, postoperative ICU care, or recovery room care, and to compare morbidity, mortality, and resource utilization among all groups. DESIGN: Prospective, observational study. SETTING: A university hospital. PATIENTS: A total of 475 patients who were referred preoperatively by surgeons for ICU consultation and were evaluated by ICU physicians. INTERVENTIONS: Patients assessed to have clinical evidence of cardiovascular compromise were admitted preoperatively to the ICU for invasive hemodynamic monitoring and optimization. Patients without such evidence, but who were to undergo major operations or had anticipated major fluid replacement were independently selected for invasive monitoring by anesthesiologists. Patients who developed physiologic instability or became unstable due to hemorrhage also underwent invasive monitoring. Nonmonitored patients who remained stable were given postoperative ICU care or went to the recovery room based on an assessment by the surgeon and anesthesiologist at the end of the operation. MEASUREMENTS AND MAIN RESULTS: Of 8,916 elective surgical cases, ICU physicians were consulted in 475 (5.3%) patients preoperatively. Sixty-seven patients were admitted preoperatively to the ICU for invasive hemodynamic monitoring and optimization; 60 patients had surgery (0.7% of elective cases, 12.6% of ICU consultations). Patients selected for ICU preoperative monitoring were older than non-monitored patients and had higher numbers of cardiovascular and total risk factors than any other group. They had higher Acute Physiology and Chronic Health Evaluation (APACHE II) scores, higher Therapeutic Intervention Scoring System (TISS) points, a higher number of complications, and longer ICU stays than non-monitored postoperative ICU patients. In addition, they had a higher number of complications than nonmonitored recovery room patients. APACHE II scores, TISS points, number of complications, and ICU days in the preoperative ICU admission group were not increased when compared with all other monitored patients. Neither hospital days nor total hospital charges were increased when compared with the other elective ICU patients. Patients selected for ICU preoperative monitoring who underwent surgery had an 11.7% mortality rate and accounted for four of five cardiovascular-related deaths. CONCLUSIONS: A small number of high-risk patients can be selected for preoperative monitoring on the basis of clinical assessment without increasing ICU stay or hospital bills. A structured preoperative consultation correctly identifies those patients who need monitoring and ICU care, but does not overutilize scarce and expensive ICU beds.

Further appraisal of APACHE II limitations and potential.

Hemodynamically unstable patients selected for invasive cardiovascular monitoring were divided into APACHE II subgroups for risk stratification to study interrelationships among monitoring, therapy, resulting cardiovascular function and outcome. When compared by regression analysis, there were no clinically relevant relationships between APACHE II scores and total intervention points (r2 = 0.02), days of invasive monitoring (r2 = 0.000001), initial cardiovascular function (r2 = 0.069) and final cardiovascular function (r2 = 0.05). Analysis of variance (ANOVA) was done between APACHE subgroups and total points (zero of 20 intragroup comparisons were different by the Scheffé test; p = 0.33), days of monitoring (zero of 20 were different; p = 0.61), initial cardiovascular function (three of 20 comparisons were different; p = 0.003) and final cardiovascular function (zero of 20 were different; p = 0.24). Opposite relationships in patients who lived and died were noted between total intervention points and APACHE II subgroups (p = 0.028, two-way ANOVA). There was an increasing number of total intervention points in patients who ultimately lived in ascending initial APACHE II subgroups. In contrast, there was a decreasing number of total intervention points in patients who ultimately died in the same APACHE II subgroups. APACHE II stratification failed to help understand the relationships among clinically important parameters. At the same time, while APACHE scores are claimed to be independent of therapy, the score seemed to be extremely sensitive to interventions, especially important in surgical populations. Should the APACHE II scores remain high in the face of continued maximal intervention, fatal outcome can be predicted. This pattern is remarkably similar across the entire initial APACHE spectrum. The predicated attributes of APACHE II scores, that is, risk stratification and independence from therapy, are neither necessary or desirable. Understanding patterns that are associated with survival or death may require alternative mathematic approaches, such as group and set theory manipulated by principles of Boolean algebra. New approaches may be more fruitful than further attempts to refine existing systems.

Evaluation of APACHE II for cost containment and quality assurance.

APACHE II (an acronym formed from acute physiology score and chronic health evaluation) has been proposed to limit intensive care unit (ICU) admissions ('cost containment') and to judge outcome ('quality assurance') of surgical patients. To judge its performance, a 6-month study of 372 surgical ICU patients was performed. When patients were divided by mean duration of stay, mortality rates rose from 1% (short stay) to 19% (long stay) (p less than 0.001) for patients with APACHE II scores less than 10, but decreased from 94% (short stay) to 60% (long stay) (p less than 0.01) for patients with APACHE II scores more than 24. Exclusion of patients by high or low APACHE scores would 'save' 6% of ICU days but risk increasing morbidity, hospital costs, and deaths. Grouped APACHE II scores did not correlate with total hospital charges (r = 0.05, p = 0.89) or ICU days used (r = 0.42, p = 0.17). Grouping by APACHE II score and duration of ICU stay showed neither symmetry nor uniformity of mortality rates. Surgical patients would not be well served by APACHE II for quality assurance or cost containment.

Titrating positive end-expiratory pressure therapy in patients with early, moderate arterial hypoxemia.

A prospective randomized study to compare two physiologic end-points for titrating positive end-expiratory pressure (PEEP) was performed in patients with early, moderate arterial hypoxemia after surgery or trauma. All patients initially received 5 cm H2O of PEEP. In group 1 patients, PEEP was increased only if PaO2 decreased below 65 torr on an inspired oxygen fraction (FIO2) of 0.45. PEEP was then added in 2- to 3-cm H2O increments until PaO2 again was above 65 torr. Group 2 patients were treated with incremental PEEP until the PaO2/FIO2 ratio was greater than 300 or physiologic shunt (Qsp/Qt) was less than 0.20. All therapy other than PEEP was similar in the two groups. There were no statistically significant differences in entry PaO2 (mean 85 +/- 11 [SD] and 87 +/- 11 torr in groups 1 and 2, respectively), and Qsp/Qt was 0.22 in each group. Five (28%) of 18 patients in group 1 and 19 (95%) of 20 patients in group 2 received more than 5 cm H2O of PEEP. Between groups 1 and 2 there were no statistically significant differences in days intubated (3.4 +/- 3 vs. 5.3 +/- 5, respectively), ICU days (5.3 +/- 3 vs. 6.6 +/- 5), hospitalization days (26 +/- 24 vs. 28 +/- 24), incidence of pulmonary barotrauma (0/18 vs. 1/20), ICU mortality (22% vs. 20%), or overall mortality (33% vs. 25%). The number of blood gas analyses and cardiac output measurements, and the total hospital charges were also similar in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk and detection of pulmonary artery catheter-related infection in septic surgical patients.

Specimen cultures were evaluated in 49 catheterized patients who had a known focus of infection (primarily intra-abdominal peritonitis). Bacteria were recovered from 2% of flush solutions, 14% of transducer domes, 18% of diaphragms, and 24% of cardiac output fluids; however, these bacteria were not found in cultures of the pulmonary artery (PA) catheter segments. The rates of positive PA catheter-aspirate cultures were 30.6% on day 1, 20.4% on day 2, and 32.7% on day 3 (not statistically different). PA catheter-aspirate cultures had a sensitivity of 5.7% and a positive predictive value of 30% for catheter-related infection, and 15% sensitivity and 40% positive predictive value for peripheral bacteremia. While 95% (55 of 58) of the catheter-aspirate cultures were false-positives, only 0.5% (3 of 588) were true-positives. Peripheral blood cultures were positive in 10% of the patients, but the catheter segments were sterile or grew different organisms. Arterial line cultures had zero sensitivity and predictive value to detect catheter-related infection, and 15% sensitivity and 40% predictive value to detect peripheral bacteremia. Thus, PA catheter-aspirate cultures, routine peripheral blood cultures, and arterial cultures cannot be recommended to detect PA catheter-related infection. Catheter-related infection confirmed by catheter-segment cultures was 10.2% when the PA catheters were removed after 73 +/- 6.5 (SD) h. Bacteria from catheter-segment cultures corresponded to those from the primary infection site.

Maintaining quality of care while reducing charges in the ICU. Ten ways.

We believed that the dilemma of controlling costs yet maintaining quality of care might be approached in 10 ways designed to improve efficiency of care: principles of management, elimination of standing orders, classification of patients, written guidelines, mandatory communication, no repetitive orders, single order for single test, removal of monitoring catheters, constant administrative attention, and feedback. We monitored quality of care using the therapeutic intervention scoring system (TISS), mortality, utilization of bed days in the ICU, and the total hospitalization of 50 patients treated in April 1983 and, 8 months after the interventions, 50 patients treated in February 1984. There were no differences in the patient population, severity, outcome, or days. The total lab bills were $10,000 in 1983 and $6300 in 1984 (p less than 0.01). The total number of tests decreased by 2803 (42%) from 6685 to 3882, or 56 per patient per admission. Calculated ICU laboratory charges per patient decreased $3226 (53%) from $6210 to $2894. In 1983, while patients spent 15% of their hospital days in the ICU, they accumulated 61% of their total laboratory charges. In 1984, ICU days were 19% and ICU laboratory charges were 46% of the total. If the decrease of $3226 per patient is extrapolated to a year's population, this would decrease charges by over $2,000,000 in one 12-bed surgical ICU.

Intravascular catheters: current guidelines for care and maintenance.

Many considerations resulting in the formulations of guidelines for the use of intravascular catheters in the care of critically ill patients are well explored and documented; other areas are highly conjectural, are virtually unchartered, or have not even been explored. The sterility of transducer and flush assembly over time, the use of a five-lumen PA catheter as an avenue for both hemodynamic measurement and nutritional support, and the meaningful interpretation of cultures obtained from all of the catheters are necessary areas of present research to replace theoretical concepts with data. We hope that the necessity for future research will provide data for the ICU practitioner to deliver the safest and most cost-effective methods of intravascular catheterization in a constantly changing environment.

Nursing assessment of intermittent mandatory ventilation.

IMV provides the ICU nurse responsible for total multifunctional patient care with many advantages. First of all, it allows more time to perform other needed tasks. Time is made available for counseling the patient and family; consulting with the social worker, occupational therapist, and other staff members; and participating actively on team patient care conferences. IMV permits the patient to perform at an optimal level throughout the ICU stay and to participate in the treatment program. This is perhaps the greatest advantage of IMV for both the nurse and the patient. The patient's comprehension and ability to communicate are not limited by sedation or anxiety, the patient is more responsive when at least some control is retained over the environment. This reassures the family. Allowing the patient to be as awake and alert as possible not only assists the staff in assessment but allows positive feedback to the patient. It is difficult for a nurse to argue with the advantages of this method in contrast to the difficulty of caring for a sedated patient receiving controlled ventilation. Incrementally decreased ventilatory support lessens anxiety during weaning, thereby minimizing one of the negative aspects of critical illness. Because less sedation is required, the patient's overall safety is improved. The ICU team can more easily find out about such problems as abdominal pain and difficulty in breathing. An alarm aids the nurse in discriminating anxiety from hypoxia/hypercapnia. With definitive guidelines for its use and careful delineation of team members' responsibilities, IMV provides the nurse with a simple, flexible, and innovative tool for patient care.