Hemodynamic effects of noninvasive bilevel positive airway pressure on patients with chronic congestive heart failure with systolic dysfunction.

BACKGROUND AND STUDY OBJECTIVES: Noninvasive positive airway pressure may play a significant role in treating patients with congestive heart failure (CHF). We tested our hypothesis that noninvasive bilevel positive airway pressure improves left ventricular performance in patients with chronic CHF secondary to severe systolic dysfunction. OBJECTIVES: To determine the cardiac performance of patients using bilevel positive airway pressure, and to describe the hemodynamic effects of bilevel positive airway pressure and its use as a therapeutic adjunct in these patients. DESIGN: Prospective, cohort, nonrandomized study. SETTING: Outpatient medicine clinic. PATIENTS: Fourteen patients (9 men and 5 women) with stable chronic CHF with left ventricular ejection fraction < or =35%; mean age was 60.6 years (range, 43 to 87 years). INTERVENTIONS: Bilevel positive airway pressure via nasal mask at an inspiratory pressure of 5 cm H(2)O and an expiratory pressure of 3 cm H(2)O on spontaneous mode at room air for 1 h. MEASUREMENTS AND RESULTS: Myocardial performance and changes were measured using clinical and echocardiographic parameters. Baseline clinical and echocardiographic parameters were compared with the same parameters after 1 h of bilevel positive airway pressure. Statistically significant (p<0.05, Wilcoxon matched pair signed-rank test) decreases were noted in these mean values: systolic BP from 136.21 to 124.14 mm Hg (p = 0.008), heart rate from 85.07 to 74.71 beats/min (p = 0.002), respiratory rate from 23.07 to 15.43 breaths/min (p = 0.001), and systemic vascular resistance from 1671. 46 to 1236.27 dyne. s. cm(3) (p = 0.001). Statistically significant increases were noted in these mean values: cardiac output from 5.09 to 6.37 L/min (p = 0.004), ejection fraction from 28.71% to 34.36% (p = 0.001), and end-diastolic volume from 224.36 to 246.21 mL (p = 0.045). CONCLUSION: Bilevel positive airway pressure has excellent potential for improving left ventricular performance of patients with chronic CHF secondary to severe systolic dysfunction.

ARDS and adrenal insufficiency associated with the antiphospholipid antibody syndrome.

The antiphospholipid antibody syndrome (APS) is typically characterized by recurrent arterial and/or venous thromboses, miscarriages, and thrombocytopenia. There have been five reported cases of ARDS associated with primary APS. Adrenal insufficiency has also been reported as a rare complication of APS. We report a case of both ARDS and adrenal insufficiency associated with primary APS. Chest radiographs and pulmonary angiography studies revealed findings consistent with ARDS. CT scans confirmed the presence of bilateral adrenal hemorrhagic infarction. Patients with APS are at an increased risk of widespread vascular thrombosis due to the presence of circulating antiphospholipid antibodies. This case emphasizes the importance of recognizing APS and its potential for multiple organ system involvement.

Significance of elevated pancreatic enzymes in intracranial bleeding.

Hyperamylasemia of pancreatic origin has been noted in patients with severe head injury without abdominal trauma or evidence of pancreatitis. Thirty-eight patients with intracranial bleeding of various types were evaluated for elevated pancreatic amylase and lipase enzymes without associated pancreatitis. Twenty-five patients had elevated serum lipase; 17 of 25 also had elevated amylase without pancreatitis. Most lipase elevations occurred earlier than those of amylase. Six clinical variables--mannitol, ceftriaxone, nimodipine, steroids, Glasgow Coma Score, and total parenteral and enteral hyperalimentation--were evaluated to determine relationship to the enzyme elevations. A significant relationship exists between patients not treated with steroids and elevated lipase and amylase enzyme activities. Multivariate analysis revealed a significant interaction between lipase elevation and decreasing Glasgow Coma Score, indicative of increasing severity of intracranial bleeding. Proposed causes of enzyme elevations in intracranial bleeding include vagal stimulation, altered modulation of the central control of pancreatic enzyme release, and release of cholecystokinin from the brain. Physician awareness of the association of intracranial bleeding with the elevation of amylase and lipase without pancreatitis can save the patient needless cost and manipulation.

Unplanned extubations.

STUDY OBJECTIVE: A prospective study of all unplanned adult extubations was conducted for 4 months period in four intensive care units (ICUs) of a community hospital. Our objective was to document the incidence of unplanned extubations, discern possible variables predictive of occurrence and outcome, and formulate preventive measures and guidelines for reintubation. DESIGN: Prospective case series. SETTING: Hospital with 525 beds and four ICUs: medical-surgical-trauma, neurology-neurosurgery, cardiovascular, and coronary care. PATIENTS: All adult patients intubated in four ICUs for a 4-month period. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Of 460 adults intubated in the 4-month period, 13 (3 percent) unplanned extubations occurred. Six patients were reintubated because of apnea, tachypnea, hypoxia, or other factors. Seven were not reintubated. Variables examined included the ventilator settings before to self-extubation, duration of intubation, arterial blood gases after self-extubation, Glasgow Coma Scale and Acute Physiology and Chronic Health Enquiry (APACHE) scores, time and location (ICU), nasal or oral method of intubation, and the mechanism of self-extubation. CONCLUSIONS: Our data suggested that self-extubation is relatively rare in our institution and that about half of self-extubated patients were reintubated. Staff vigilance, a proper weaning period, and the nasal method of intubation were some of the factors to which we attributed this low occurrence rate. However, a larger patient study population is required to show conclusively effective preventive measures and establish guidelines for reintubation.

Pulse oximetry monitoring can change routine oxygen supplementation practices in the postanesthesia care unit.

Routine use of supplemental oxygen (O2) in the postanesthesia care unit (PACU) traditionally has been used to minimize the incidence of hypoxemia. However, with the advent of continuous noninvasive monitoring by pulse oximetry, is routine administration of O2 necessary? We hypothesized that administering O2 as needed, based on pulse oximetry data, would effect considerable cost savings without compromising patient care. Five hundred adult (> or = 18 yr) patients breathing room air when arriving in the PACU were enrolled in the study. During PACU care, when O2 saturation (SpO2) was continuously more than 94%, no supplemental O2 was given. When SpO2 was less than 94%, supplemental O2 was given at an inspired O2 concentration (FIO2) that would increase it to above 94%. Also, when preoperative SpO2 was less than 94% and postoperative SpO2 was more than the preoperative SpO2, no supplemental O2 was given. Supplemental O2 was unnecessary in 63% of patients for the duration of their PACU stay. Cost savings to the 307 patients in one study not receiving O2 was $31,928 if it had been billed separately from the PACU global charge. The annualized figure for patients in our hospital (approximately 10,000 cases) would be an additional $623,272. Inasmuch as pulse oximetry monitoring is now standard in the PACU, perhaps it is time to apply the objective data it supplies, thereby creating cost savings while maintaining patient care standards.

The treatment of osteomyelitis underlying pressure ulcers.

Osteomyelitis is recognized as an often intractable hindrance to healing in the deep pressure ulcer. The mainstays of treatment of this disease have traditionally been surgical debridement followed by muscle flap revascularization, supplemented by antibiotic coverage. Hyperbaric oxygenation has also been shown to be effective in healing refractory osteomyelitis when used as an adjunct to surgical and medical therapy. This review defines the disease, and presents a current literature review and discussion of its treatment, including adequacy of debridement, options for wound closure, appropriate antimicrobial strategy, and the role of hyperbaric oxygenation. A short review of investigational modalities is also included.

Right ventricular hypertrophy detected by echocardiography in patients with newly diagnosed obstructive sleep apnea.

We used polysomnography, echocardiography and ventilatory measurements to study 50 patients suspected of having OSA to determine a link to RVH. Twenty-eight patients (56 percent) had OSA and 20 (71 percent) of those had isolated RVH. We evaluated patients with RVH and divided them into two groups, those with apnea and those without apnea. The patients with sleep apnea were younger, weighed more, had greater BSA and had lower average oxygen saturations during the sleep study period. We divided the group with apnea into those with RVH and those without it. Those patients with RVH had a higher AI, longer average apnea time, a greater duration of longest apnea and a lower average oxygen saturation for the period of the sleep study. In addition, those with RVH had a lower average oxygen saturation during each apneic episode with a p value equaling 0.09.

Effect of positive end-expiratory pressure on intra-abdominal pressure.

Massive elevation of intra-abdominal pressure (IAP) causes renal, cardiovascular, and respiratory dysfunction. Positive end-expiratory pressure (PEEP) markedly increases the detrimental effect of IAP on the cardiovascular system. The purpose of this study was to determine the effect of PEEP on IAP. In 15 patients requiring mechanical ventilation, IAP was measured, after 15-minute equilibration intervals, at PEEP levels of 0, 5, 10, and 15 cm H2O. Parametric analysis with multiple paired t tests and nonparametric analysis with Spearman's rho and Kendall's tau tests were used to determine correlation between PEEP and IAP. All patients were male. The mean age was 39 years (range, 18-77). Ten patients had just had laparotomy. No correlation was found between PEEP and IAP. We conclude that PEEP of 15 cm H2O or less has no effect on IAP, and we discuss the clinical implications.

Pressure control inverse ratio ventilation as a method to reduce peak inspiratory pressure and provide adequate ventilation and oxygenation.

Nineteen patients with ARDS or pneumonia who were ventilated with PcIRV on the Siemens-Elema Servo 900 C were retrospectively reviewed. The PcIRV reduced peak airway pressure, PEEP, increased Paw, and improved ventilation and oxygenation in these patients. When these patients were compared with themselves on prior conventional IPPV, all had a decrease in PIP, an increase in Paw and most had a decrease in VE, with no change in PaCO2 and an increase in PaO2. The increase in Paw may have contributed to this improved arterial oxygenation. High levels of PIP and PEEP during IPPV have been identified as risk factors in the development of barotrauma and residual parenchymal pulmonary damage. We propose that PcIRV allows for adequate ventilation and oxygenation with decreases in PIP, extrinsically added PEEP and inspired O2 concentration. This mode of ventilation may decrease the morbidity associated with IPPV utilizing high PIP and PEEP.

Single arterial puncture vs arterial cannula for arterial gas analysis after exercise. Change in arterial oxygen tension over time.

In an attempt to find the least invasive, safest, easiest, and cheapest method of obtaining resting and exercise samples of arterial blood, a comparison was made between samples from an arterial needle puncture and an arterial cannula. This study demonstrated that samples of arterial blood may be obtained by radial arterial puncture both at rest and during exercise in practically all cases without morbidity. Samples from arterial needle puncture provide the same results as those from arterial cannulas. In the very rare patient in whom arterial puncture during maximal exercise is unsuccessful, the arterial oxygen pressure (PaO2) measured at 10 seconds after exercise correlates very well with the PaO2 at maximal exercise, and the 15-second value correlates nearly as well. Arterial cannulas are needed in the infrequent case when arterial puncture is not accomplished during maximal exercise and the 10-second or 15-second PaO2 decreases from the resting value. In this instance, determination of the exact extent of the hypoxemia requires an exercise sample obtained by cannula; however, the decrease in PaO2 obtained by arterial needle puncture at 10 or 15 seconds will be all that is needed many times to make a clinical decision. Values obtained at 20 seconds after maximal exercise reflect less of the exercise measurement and cannot be used; however, all episodes of significant hypoxemia (PaO2 less than 60 mm Hg) were captured by the analysis at 20 seconds after exercise.