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Constantine A Manthous

Publications and source records attributed to Constantine A Manthous.

29 records · Page 2Linked to original sources
PubMed2004

Determinants of dynamic hyperinflation in a bench model.

BACKGROUND: Previous in vivo data suggest that high airway resistance (R(aw)) promotes dynamic hyperinflation, especially when coupled to high minute ventilation (V(E)). However, no studies have systematically examined the relative effects of various mechanical parameters on dynamic hyperinflation. METHODS: Intrinsic positive end-expiratory pressure (PEEPi) was measured with a ventilator-lung model, over a range and various permutations of R(aw), V(E), respiratory system compliance (C(RS)), and duty cycles/flow regimes. RESULTS: Substantial dynamic hyperinflation (PEEPi > 5 cm H(2)O occurred at various V(E), even when R(aw) was low (4 cm H(2)O/L/s) or just above normal (18 cm H(2)O/L/s). A V(E) > or = 15 L/min was associated with increasing PEEPi in this model, across a broad range of mechanical permutations. PEEPi was significantly higher in all models during descending ramp flow than during constant flow, at equivalent peak flows (wherein duty cycle during descending ramp flow was twice that of constant flow). PEEPi was equivalent when duty cycles (and all other mechanical parameters) were equal. PEEPi was significantly greater, irrespective of duty cycle, R(aw), and C(RS), when delivered with lower tidal volume (0.6 L vs 1.0 L). The change in peak airway pressure associated with development of dynamic hyperinflation was consistently greater than the observed PEEPi. Higher V(E), resistance, compliance, and duty cycles were all independently associated with dynamic hyperinflation. CONCLUSIONS: In this bench model, dynamic hyperinflation occurred with high V(E), even at low R(aw). Since moderate R(aw) and V(E) frequently occur in vivo, even without obstructive lung disease, occult dynamic hyperinflation is likely to occur commonly. PEEPi was greater with high frequency and small tidal volume (0.6 L) than with equal V(E) of lower frequency and larger tidal volume (1.0 L).

Equipment Design↗
PubMed2003

Gender and status asthmaticus.

BACKGROUND: Adult women may be more susceptible to asthma than men. HYPOTHESIS: Women are more likely to develop status asthmaticus (SA) requiring critical care. METHODS: The medical records of patients admitted to our medical intensive care unit (ICU) for SA between 1994 and 2000 were examined. A number of demographic and physiologic variables were extracted from the medical records. RESULTS: Of 103 total admissions, 53 (of 37 patients) were age < 50 years and had clinical evidence suggesting SA. Among these 37 patients, the average (+/-SE) age was 30.8 +/- 1.0 y with average acute physiology and chronic health evaluation (APACHE) II of 9.5 +/- 0.8. Seventeen patients were Hispanic, 13 were black, and 7 were white. Twenty-four patients (accounting for 37 admissions) were female and 13 patients (16 admissions) were male. Although women accounted for a greater absolute number of endotracheal intubations (ETI; 17 vs. 12) and were more likely to be admitted to ICU more than once (7 vs. 3), men had a higher incidence of ETI (RR=1.6; 95%CI=1.04-2.6). The need for using therapeutic permissive hypercapnia and lengths of stay (ventilator, ICU, and hospital) were similar between men and women. Two patients, both women, died of causes not related to treatment of SA. CONCLUSIONS: These data suggest that although women accounted for more ICU admissions for SA, men were more likely to require ETI.

Adult↗
PubMed2003

Cough peak flows and extubation outcomes.

BACKGROUND: Semiobjective methods of quantifying cough strength and endotracheal secretions have been demonstrated to predict extubation outcomes of patients who have passed a spontaneous breathing trial (SBT). HYPOTHESIS: Cough strength, measured by voluntary cough peak expiratory flow (PEF), and endotracheal secretions, measured volumetrically, predict extubation outcomes of patients who have passed an SBT. PATIENT POPULATION: Critically ill patients admitted to the medical ICU of a 300-bed community teaching hospital. METHODS: All patients who passed an SBT and were about to be extubated were studied. The best of three cough attempts, measured with an in-line spirometer, and the average hourly rate of suctioned secretions prior to extubation were recorded with other weaning parameters and demographic data. RESULTS: Ninety-five patients were studied before and after 115 extubations. There were 13 unsuccessful extubations. There were no differences in age, gender, duration of intubation, or APACHE (acute physiology and chronic health evaluation) II scores between successful and unsuccessful extubations. The magnitude of endotracheal secretions was not associated with outcomes. The PEF of patients with unsuccessful extubations was significantly lower than that of those with successful extubations (64.2 +/- 6.8 L/min vs 81.9 +/- 2.7 L/min, p = 0.03). Patients with unsuccessful extubations stayed longer in the ICU than those with successful extubations (11.7 +/- 2.1 days vs 5.3 +/- 0.4 days, p = 0.009). Those with PEF <or= 60 L/min were five times as likely to have unsuccessful extubations and were 19 times as likely to die on that hospital stay. PEF and the rapid shallow breathing index were independently associated with extubation outcomes, while only the PEF (<or= 60 L/min) was independently associated with in-hospital mortality. CONCLUSION: These data suggest that cough strength, measured objectively, is a predictor of extubation outcome, morbidity, and mortality.

APACHE↗
PubMed2003

Informed consent for medical procedures: local and national practices.

BACKGROUND: No studies have assessed whether clinicians obtain informed consent for invasive medical procedures, and there are no explicit national standards to guide the process. HYPOTHESIS: Informed consent practices are inconsistent for commonly performed invasive medical procedures. METHODS: A simple questionnaire was electronically mailed and/or faxed to training program directors of critical care medicine and internal medicine departments, and to ICU directors in the state of Connecticut. The questionnaire listed common invasive medical procedures and asked the respondents to check those for which practitioners routinely obtain informed consent in their hospital. RESULTS: The three samples, national intensivists (88 respondents), Connecticut intensivists (29 respondents), and national internists (56 respondents) demonstrated heterogeneity of consenting practices. The rate of obtaining consent for common vascular access procedures ranged from 20 to 90%. The rates of obtaining consent for Foley catheterization and nasogastric intubation were uniformly < 10%, and those for endoscopic procedures were > 90%. Separate consent (beyond the general consent to treat) was not uniformly obtained for the transfusion of blood products (range, 74 to 93%) and common diagnostic medical procedures (eg, thoracentesis, paracentesis, or lumbar puncture; range, 77 to 96%). Surgical intensivists reported that the obtaining of consent for invasive procedures was less routine compared to medical intensivists. Lower rates of consent were noted by those respondents who used a "blanket" consent form, which was signed at the time of hospital admission, to cover subsequent procedures. CONCLUSIONS: In this relatively small sample, there was no uniform practice of informed consent for commonly performed invasive medical procedures. Consent was routinely obtained for GI endoscopy, bronchoscopy, and medical research, and was not obtained for Foley catheterization and nasogastric intubation. The obtaining of consent for vascular cannulation and diagnostic procedures was not routine in the ICUs of a substantial number of respondents. Explicit standards that delineate specifically which procedures require consent may be required to assure more uniform practices.

Connecticut↗
PubMed2003

Are living wills useful? In search of a new paradigm.

Living wills are written by patients to direct physicians and loved ones as to the medical care they want in the event of catastrophic illness that is accompanied by inability to communicate their wishes. We outline recent data suggesting that living wills are poorly understood by patients who have them and that the usefulness of these documents in the clinical arena is extremely limited. Potential solutions for current deficiencies in end-of-life care and decision-making are discussed.

Connecticut↗
PubMed2003

The effect of arterial blood gas values on extubation decisions.

BACKGROUND: No studies have examined the clinical utility of arterial blood gas (ABG) values during spontaneous breathing trials (SBTs) for making extubation decisions. Nonetheless many intensive care units measure ABGs during an SBT to determine, in conjunction with other data, whether the SBT was successful. OBJECTIVE: Determine how often ABG values change extubation decisions. METHODS: Each patient was assessed at the bedside by one of 3 critical care attending physicians. Each assessment was made at the end of the SBT in which ABGs were obtained with the expectation of extubation. When a nurse, respiratory therapist, or resident was available, he or she also simultaneously and independently evaluated the patient and then reassessed with the ABG values. Physiologic data were recorded before and during the SBT, as the attending physician performed the bedside assessment. RESULTS: Eighty-three patients were studied during 100 SBTs. Heart rate, respiratory rate, and mean blood pressure increased. Blood oxygen saturation (measured via pulse oximetry [F(IO)(2)]) and the P(aO)(2)/F(IO)(2) ratio decreased significantly during SBTs. Concordant clinical and ABG assessment (to attempt a trial of extubation) led to extubation in 86 patients, 76 of whom remained extubated after 72 hours. Following 14 of the SBTs, the patients were not extubated. Seven of these were judged by the attending physicians to fail both clinically and following review of ABG values. Seven were judged successful clinically, but the patients were not extubated because the attending physician thought the ABG values were unfavorable. Bedside nurses, who assessed 72 SBTs, had 1 case in which the ABG values changed their extubation opinion. Resident-trainees assessed 76 cases and had 5 changes of opinion based on ABG values. Respiratory therapists assessed 77 patients and had 4 such cases. The average changes in heart rate and blood pressure of patients not extubated were double those of extubated patients, but there were no significant differences in respiratory rate or P(aO)(2)/F(IO)(2) ratio between those groups. Ten patients (11.6%) were extubated based on the attending physician's decision but required re-intubation within 72 hours. CONCLUSION: These data suggest that ABG values did not change extubation decisions in 93% of cases. However, in 7 cases the ABG values changed the extubation decision. If even a few of those cases would have failed extubation without knowledge of the ABG values, the increased patient risk and cost associated with failed extubation would more than offset the relatively small cost of collecting ABG values from all patients who undergo SBT.

Adult↗
PubMed2002

Patient, physician, and family member understanding of living wills.

This study examines understanding of living wills by patients, family members, and physicians. Questionnaires were used to examine whether each cohort understood patients' living wills regarding endotracheal intubation and cardiopulmonary rescuscitation (CPR). Of 4,800 patients admitted during the study period, 206 reported having living wills, all of which precluded intubation and CPR for "terminal conditions." Of 140 admitted to the general hospital wards, 17 (12%) wanted their living wills to preclude intubation/mechanical ventilation and 12 (8.6%) did not want resuscitation under any circumstances. Seven of 120 (6%) physicians and 4 of 108 family members would not intubate or perform CPR even if there was a chance of recovery. Of 88 patients with complete data (including physicians and family members), 29 (33%) wanted their living wills to block intubation/mechanical ventilation only if they were deemed terminal and 46 (52%) wanted the living will to block intubation even if there was a 10% chance of recovery. Thirteen (15%) wanted to block intubation even if the chance of recovery was > or = 50. Results were similar for wishes regarding CPR. These data suggest substantial differences of patient, physician, and family member understanding of living wills. Living wills did not reflect fully patients' expectations of receiving (or not receiving) life-sustaining modalities.

Adult↗
PubMed2002

Propofol infusion is associated with a higher rapid shallow breathing index in patients preparing to wean from mechanical ventilation.

OBJECTIVE: To determine whether propofol affects spontaneous breathing patterns in critically ill patients recovering from respiratory failure during initial attempts at liberation from mechanical ventilation. DESIGN: Observational cohort study. PATIENTS: Ten critically ill patients in the medical intensive care unit of a 300-bed community teaching hospital. MEASUREMENTS: Demographic and physiologic variables, including respiratory frequency and minute volume, were recorded while patients breathed on continuous positive airway pressure (of 5 cm H(2)O) during and 20-30 min after cessation of propofol infusion. The ratio of respiratory frequency to tidal volume (rapid shallow breathing index or RSBI) was computed for both sets of measurements and values measured during and after propofol infusion were compared. RESULTS: The mean (+/- SEM) age was 54.0 +/- 5.2 years and the mean (+/- SEM) APACHE II (Acute Physiology and Chronic Health Evaluation) score was 18.4 +/- 2.0. During propofol infusion, patients breathed with a significantly lower tidal volume (0.245 vs 0.342 L, p = 0.006), higher RSBI (155.6 vs 114.8 breaths/min/L, p = 0.004), and tended to breathe more rapidly (34.3 vs 31.7 breaths/min, p = 0.18) than at 20-30 min after stopping propofol infusion. Three of 10 patients had RSBIs that were unfavorable (> 105 breaths/min/L) for weaning while on propofol but that became favorable (< 105 breaths/min/L) 20-30 min following cessation of propofol. The weight-adjusted dose of propofol was not correlated with the changes in any of the variables. CONCLUSIONS: Propofol causes changes in breathing pattern that could lead a caregiver to erroneously conclude that a patient is not ready to begin spontaneous breathing trials. Since this effect has also been noted following benzodiazepine infusion, the clinician should consider the patient's "sedation history" when using RSBI to guide weaning decisions.

APACHE↗