The impact of emergency department segmentation and nursing staffing increase on inpatient mortality and management times

Background

The aim of our study was to investigate the impact of a new organization of our emergency department (ED) on patients’ mortality and management delays.

Methods

The ED segmentation consisted of the development of a new patient care geographical layout on a pre-existing site and changing the organization of patient flow. It took place on May 10, 2012. We did a before-after study in the ED of a university hospital, “before” (winter 2012) and “after” (summer 2012) reorganization by segmentation into sectors. All ED patients were included.

Results

Eighty-three thousand three hundred twenty-two patient visits were analyzed, 61,118 in phase “before”, 22,204 during the phase “after”. The overall inpatient mortality was 1.5 % during summer 2011 (“before” period), 1.8 % during winter 2012 (“before” period), 1.3 % during summer 2012 (“after” period) period (summer 2012 vs. winter 2012, OR = 0.72; 95 % CIs [0.61, 0.85], and summer 2012 vs. summer 2011, OR = 0.85; 95 % CIs [0.72, 0.99]). The mean (SD) time to first medical contact was 129 min (±133) during winter 2012 and 104 min (± 95) during summer 2012 (p < .05).

Conclusions

Our study showed a decrease in mortality and improvement in time to first medical contact after the segmentation of our ED and nursing staffing increase, without an increase in medical personnel. Improving patient care through optimizing ED segmentation may be an effective strategy.

Clinical practice and risk factors for immediate complications of endotracheal intubation in the intensive care unit: a prospective, multiple-center study

OBJECTIVES

To describe the current practice of physicians, to report complications associated with endotracheal intubation (ETI) performed in THE intensive care unit (ICU), and to isolate predictive factors of immediate life-threatening complications.

DESIGN

Multiple-center observational study.

SETTING

Seven intensive care units of two university hospitals.

PATIENTS

: We evaluated 253 occurrences of ETI in 220 patients.

INTERVENTIONS

From January 1 to June 30, 2003, data related to all ETI performed in ICU were collected. Information regarding patient descriptors, procedures, and immediate complications were analyzed.

MEASUREMENTS AND MAIN RESULTS

The main indications to intubate the trachea were acute respiratory failure, shock, and coma. Some 148 ETIs (59%) were performed by residents. At least one severe complication occurred in 71 ETIs (28%): severe hypoxemia (26%), hemodynamic collapse (25%), and cardiac arrest (2%). The other complications were difficult intubation (12%), cardiac arrhythmia (10%), esophageal intubation (5%), and aspiration (2%). Presence of acute respiratory failure and the presence of shock as an indication for ETI were identified as independent risk factors for occurrence of complications, and ETI performed by a junior physician supervised by a senior (i.e., two operators) was identified as a protective factor for the occurrence of complications.

CONCLUSIONS

ETI in ICU patients is associated with a high rate of immediate and severe life-threatening complications. Independent risk factors of complication occurrence were presence of acute respiratory failure and presence of shock as an indication for ETI. Further studies should aim to better define protocols for intubation in critically ill patients to make this procedure safer.

L-alanyl-L-glutamine dipeptide-supplemented total parenteral nutrition reduces infectious complications and glucose intolerance in critically ill patients: the French controlled, randomized, double-blind, multicenter study

OBJECTIVE

Glutamine (Gln)-supplemented total parenteral nutrition (TPN) improves clinical outcome after planned surgery, but the benefits of Gln-TPN for critically ill (intensive care unit; ICU) patients are still debated.

DESIGN

Prospective, double-blind, controlled, randomized trial.

SETTING

ICUs in 16 hospitals in France.

PATIENTS

One-hundred fourteen ICU patients admitted for multiple trauma (38), complicated surgery (65), or pancreatitis (11).

INTERVENTIONS

Patients were randomized to receive isocaloric isonitrogenous TPN via a central venous catheter providing 37.5 kcal and 1.5 g amino acids.kg-1.day-1 supplemented with either L-alanyl-L-glutamine dipeptide (0.5 g.kg-1.day-1; Ala-Gln group, n=58) or L-alanine+L-proline (control group, n=56) over at least 5 days.

MEASUREMENTS AND MAIN RESULTS

Complicated clinical outcome was defined a priori by the occurrence of infectious complications (according to the criteria of the Centers for Disease Control and Prevention), wound complication, or death. The two groups were compared by chi-square test on an intention-to-treat basis. The two groups did not differ at inclusion for type and severity of injury (mean simplified acute physiology score II, 30 vs. 30.5; mean injury severity score, 44.9 vs. 42.3). Similar volumes of TPN were administered in both groups. Ala-Gln-supplemented TPN was associated with a lower incidence of complicated outcome (41% vs. 61%; p<.05), which was mainly due to a reduced infection rate per patient (mean, 0.45 vs. 0.71; p<.05) and incidence of pneumonia (10 vs. 19; p<.05). Early death rate during treatment and 6-month survival were not different. Hyperglycemia was less frequent (20 vs. 30 patients; p<.05) and there were fewer insulin-requiring patients (14 vs. 22; p<.05) in the Ala-Gln group.

CONCLUSIONS

TPN supplemented with Ala-Gln dipeptide in ICU patients is associated with a reduced rate of infectious complications and better metabolic tolerance.

Anaesthesia in the older patient

PURPOSE OF REVIEW

Clinical anaesthesia and analgesia address a growing number of elderly surgical patients. Ageing modifies physiology, pharmacokinetics and pharmacodynamics, and comorbidity is a common occurrence in the elderly. Therefore, based on recent information regarding perioperative outcome, indications and techniques should be individualized.

RECENT FINDINGS

Clinical studies have highlighted the occurrence of postoperative cognitive dysfunction in elderly patients, and have given some information on its risk factors. As pain was found to be one of the most important of these, this review is also focused on the management of perioperative pain. Recently published studies have compared epidural analgesia and parenteral analgesics; others have described the handling of parenteral opioids for postoperative analgesia in elderly patients, and the opioid-sparing effect of multimodal analgesia.

SUMMARY

Postoperative cognitive dysfunction (POCD) is quite frequent. If late POCD seemed not related to the type of anaesthesia and analgesia provided, early POCD (interval delirium) was found to be related to perioperative haematocrit and transfusion requirement and to postoperative pain. Epidural analgesia using local anaesthetics and/or opioids was found to be probably better than parenteral opioids for the control of postoperative pain and the prevention of postoperative morbidity and mortality. However, well implemented protocols of parenteral analgesics could be nearly as efficient.

[Anesthesia and obesity]

Problems encountered during anesthesia procedures in obese subjects is related to the level of overweight. Obesity multiplies the effect of general anesthesia on the respiratory function and increases the postoperative risk of cardiovascular disorders and deep vein thrombosis. The pharmacokinetic behavior of most general anesthesia drugs is affected by the mass of adipose tissue producing a prolonged less predictable effect. Control of airway permeability and continence is also a major problem with predictable or unpredictable difficulties with endotracheal intubation. Locoregional anesthesia, which avoids the intubation problem, is difficult to implement and does not provide satisfactory results in all cases. The preoperative work-up should assess the consequences of obesity, particularly concerning the respiratory, cardiovascular, and metabolic systems. A proper work-up allows the anesthesist to provide the obese subject with well-informed information on the risk and benefit of proposed options.

Regional blood flows are affected differently by PEEP when the abdomen is open or closed: an experimental rabbit model

OBJECTIVE

The study of induced circulatory changes requires simultaneous assessment of multiple regional circulations because of interactions and compensatory mechanisms. Positive end expiratory pressure mechanical ventilation (PEEP) is known to cause marked, and potentially deleterious, cardiovascular changes. Our aim was to use a comprehensive approach to assess PEEP-induced circulatory changes in open vs closed abdomen animals.

MATERIAL AND METHODS

In the anesthetized rabbit, we used implantable Doppler micro-probes to measure blood flow simultaneously in the ascending aorta, inferior vena cava, portal vein, hepatic artery, common carotid artery, and renal artery. We studied spontaneously breathing animals (Group A), and open (Group B) and closed abdomen (Group C) animals mechanically ventilated at 0 (ZEEP) and 12 cm H(2)O PEEP.

RESULTS

In Group A, all biological and hemodynamic variables remained unchanged for three hours at the end of the surgical procedure. In Groups B and C, ZEEP produced no significant hemodynamic change. PEEP induced a decrease in carotid, hepatic, and renal artery blood flow in Groups B and C, a decrease in heart rate and mean arterial blood pressure in Group B, and a decrease in aorta blood flow in Group C.

CONCLUSIONS

These experimental results demonstrate the usefulness of the comprehensive approach of circulatory changes, and confirm that PEEP may have deleterious effects on regional blood flow, even without significant change in cardiac output, especially when the abdomen is open.

The Mini Nutritional Assessment-Short Form for preoperative nutritional evaluation of elderly patients

The Mini Nutritional Assessment (MNA) is a clinical tool designed for assessing nutritional status of elderly patients. Used in preoperative evaluation of ambulatory patients over 60 years of age seen on anesthesia consultation in a previous study, it identified 6.9% patients with overt malnutrition out of a group of 408. However, four-fifths of 291 ASA 1-2 patients were well nourished, and underwent needless, non-contributory and time-consuming test. The MNA-Short Form (MNA-SF) has recently been devised as the first step of a two-step process: if negative, there would be no need to complete "full" MNA. Therefore, the base data of 408 MNA forms completed during the above-mentioned study was used for the purpose of comparing the MNA-SF to the MNA, to test whether the MNA-SF could have been the first step of a two-step nutritional evaluation of anesthesia patients. Median (range) age, and BMI were 72 (60-98) years, and 25.2 (12.8-40.4) kg x m(-2), respectively. There were equal numbers of men and women. In 144 cases, the MNA-SF was found positive (35.3%) with a median MNA of 21.5 (1.5-27) points. The MNA-SF predicted absence of overt malnutrition revealed by the MNA, with 100% sensitivity and negative predictive value (NPV). It was found less efficient for predicting absence of "possible" nutritional problems detected by the MNA (sensitivity 85.6% and NPV 92.8%). However, none of the 19 borderline patients would have had overt malnutrition, being only found "at risk of malnutrition" by the MNA. On the studied sample, the MNA-SF would have correctly sorted out 69.5% of the patients without severe malnutrition. We believe the MNA-SF should be used as the first step of an efficient preoperative nutritional evaluation of ambulatory elderly patients.

Diaphragm movement before and after cholecystectomy: a sonographic study

Respiratory disorders after abdominal surgery are commonly explained by changes in diaphragmatic movement that are difficult to demonstrate and quantify. Our aim was thus to quantify these changes using a noninvasive method. We used M-mode sonography for the prospective study to measure diaphragmatic amplitude in 14 patients before and after cholecystectomy. During quiet breathing, the diaphragm inspiratory amplitude (DIA) was significantly decreased after surgery from 1.4 +/- 0.2 cm to 1 +/- 0.1 cm and from 1.6 +/- 0.3 cm to 1.2 +/- 0.3 cm in the Laparoscopic and Open Cholecystectomy groups, respectively. The total time cycle of diaphragmatic motion decreased significantly in the two groups. The DIA also decreased significantly during deep breathing after cholecystectomy from 6.0 +/- 0.8 cm to 3.0 +/- 1.8 cm and from 6.1 +/- 1.3 cm to 3.1 +/- 1.6 cm in the Laparoscopic and Open Cholecystectomy groups, respectively. The six patients who underwent spirometric examination showed, during quiet breathing, a significant decrease in DIA without change in tidal volume, i.e., 0.51 +/- 0.08 L to 0.45 +/- 0.08 L. We found a significant decrease in DIA after cholecystectomy and a significant interindividual correlation between DIA during deep inspiration and inspiratory capacity. Using M-mode sonography techniques, we were able to demonstrate changes in diaphragmatic mobility after laparoscopic or open cholecystectomy.

IMPLICATIONS

Cholecystectomy at times results in impaired respiratory and diaphragmatic functions. The techniques currently used to study these repercussions are both laborious and invasive. Our sonographic technique is completely noninvasive and can be used to study diaphragm morphology and movement in real time.

Evaluation of incidence, clinical significance, and prognostic value of circulating cardiac troponin I and T elevation in hemodynamically stable patients with suspected myocardial contusion after blunt chest trauma

BACKGROUND

The frequency and prognostic influence of myocardial injury in patients with blunt chest trauma is controversial. We investigated the value of cardiac troponin I (cTn-I) and cardiac troponin T (cTn-T), highly specific markers of myocardial injury, to determine whether their measurement would improve the ability to detect myocardial contusion in stable patients with blunt chest trauma in comparison with conventional markers and whether they were associated with significantly worse late clinical outcome.

METHODS AND RESULTS

Over an 18-month period, myocardial contusion was diagnosed in 26 of 94 patients (27.6%) with acute blunt chest trauma (motor vehicle crash; 81%), because of echocardiographic abnormalities (n = 12), electrocardiographic abnormalities (n = 29), or both. Patients with myocardial contusion had a significantly higher Injury Severity Score at the time of admission (p = 0.001) and a significantly longer hospital stay (p = 0.0008). All patients survived admission to hospital and were hemodynamically stable. None of the patients died or had severe in-hospital cardiac complications. The percentage of patients with elevated CK, (CK-MB/total CK) ratio, or CK-MB mass concentration was not significantly different between patients with or without myocardial contusion. However, there were significant differences between the two groups when we applied the commonly used threshold levels of CK-MB activity and myoglobin. The percentage of patients with elevated circulating cTn-I and cTn-T (> or = 0.1 microg/L) was significantly higher in patients with myocardial contusion (23% vs. 3%; p = 0.01 and 12% vs. 0%; p = 0.03, respectively). Complete changes in cTn-I and cTn-T correlated well (r = 0.91, p = 0.0001). Sensitivity, specificity, and negative and positive predictive values of cTn-I and cTn-T in predicting a myocardial contusion in blunt trauma patients were 23%, 97%, and 77%, 75%, and 12%, 100%, and 74%, 100%, respectively. Clinical follow-up was available in 83 patients (88%) (mean, 16 +/- 7.5 months). There were no deaths in either group directly attributed to cardiac complications. None of the patients had any long-term cardiac complications or myocardial failure related to blunt chest trauma.

CONCLUSION

Although improved specificity of cTn-I and cTn-T compared with conventional markers, it should be emphasized that the main problem with cTn-I and cTn-T is low sensitivity as well as low predictive values in diagnosing myocardial contusion. cTn-I and cTn-T measurement is currently not an improved method in diagnosing blunt cardiac injury in hemodynamically stable patients. Moreover, there was no association of postmyocardial contusion cell injury and late outcome in these patients when cTn-I and cTn-T and other conventional markers were considered.

Preoperative nutritional evaluation of elderly patients: the Mini Nutritional Assessment as a practical tool

BACKGROUND AND GOAL

Age and malnutrition are each surgical risk factors. Because the Mini Nutritional Assessment (MNA) has been specifically designed for assessing the nutritional status of elderly patients, it can be used for preoperative nutritional evaluation. Therefore, the MNA was included in the preoperative clinical evaluation of patients over 60 years of age to describe their nutritional status.

METHODS

Every patient over 60 years of age, scheduled for elective surgery, was seen in anaesthesiology consultation and was submitted to the MNA. The MNA is a clinical score consisting of four additive items: 'Anthropometric assessment' based on BMI, mid-arm and calf circumferences, weight loss; global evaluation; dietetic assessment, and subjective assessment - these last three items being obtained through a specific questionnaire. It requires no biological marker. Awarding to the obtained score, the MNA stratifies patients in the following categories: well-nourished (24 </= MNA </= 30), at risk of malnutrition (17 </= MNA < 23.5), and undernutrition (MNA < 17). Also recorded were: age, gender, type of scheduled operation, and the American Society of Anesthesiologists (ASA) physical status score. Results are given as median (extremes).

RESULTS

Four hundred and nineteen patients (50.4% women) were seen between January and October 1996. The mean age was 72 years (range, 60-98 years); BMI: 25.2 (12.8-40.4) kg m(-2). The MNA score was recorded in 408 patients, ranging from 1.5 to 30 (median: 26). According to the score, the patients were stratified in: well-nourished, 276 patients (67.6%), at risk, 104 patients (25. 5%) and suffering from overt malnutrition, 28 patients (6.9%). According to the ASA score, 290 patients were found to be at low or mild risk for anaesthesia and surgery (ASA 1 and 2), and 72 patients (24.8%) were stratified as being at least at risk of malnutrition. One hundred and eighteen other patients were found to be at a higher risk (ASA 3 and 4), and 58 (49.2%) were not well-nourished (MNA < 24).

CONCLUSION

The MNA was found to be well-suited for the preoperative assessment during anaesthesia consultation because it required no biological marker. It showed that approximately one-third of all the examined patients, and half of the ASA 3-4 patients, were not well-nourished. The ASA score could not predict poor nutritional status. The results suggested that nutritional assessment should be routinely performed in ASA 3-4 patients over 60 years of age.

[Pressure-controlled mechanical ventilation: a simplified titration method of the extrinsic positive expiratory pressure]

OBJECTIVES

Extrinsic positive end-expiratory pressure (PEEPe) may improve gas distribution within the lungs, induce alveolar recruitment or, conversely, produce pulmonary overdistension, and modify the respiratory impedance. Under pressure-controlled mechanical ventilation (PCV) this phenomenon modifies the minute ventilation and the dynamic compliance of the respiratory system (Crs,dyn). This study was aimed to assess the incidence of a significant gain in Crs,dyn under the effect of PEEPe during PCV.

STUDY DESIGN

Prospective, open, descriptive, case series study.

PATIENTS

Surgical intensive care unit patients, under sedation, neuromuscular blockade and PCV because of severe hypoxaemia (ARDS or acute lung injury).

METHODS

Four incremental levels of PEEPe (4 to 16 cmH2O) of 30 minute duration were applied. Crs,dyn, and PaO2/FIO2 were recorded at the end of each level of PEEPe. The resulting gain in Crs,dyn was calculated and considered as significant if it was greater than the upper limit of confidence (at 99.8%) of the statistical distribution of all the recorded gains.

RESULTS

Thirty patients were included, median and extreme values (within brackets) of PaO2/FIO2 of 117 [53-230] and Crs,dyn without PEEPe of 29 [14.3-46.8] mL.cmH2O-1. Among the 120 recorded gains, a gain in Crs,dyn was found significant at least once in 15 tests of PEEPe out of 30. Within the two groups of patients, the increase in PaO2/FIO2 with incremental PEEPe was similar. The levels of PEEPe producing the greatest increase in Crs,dyn were not correlated with the increase in PaO2/FIO2.

CONCLUSION

In 50% of the studied patients a significant gain in Crs,dyn was found, allowing a less traumatic PCV. These results suggest the clinical usefulness of this method of titration of PEEPe, which requires neither specific devices nor a disconnection of the patient.

Non-invasive quantification of diaphragm kinetics using m-mode sonography

PURPOSE

The standard conditions of spirometry (i.e., wearing a noseclip and breathing through a mouthpiece and a pneumotachograph) are likely to alter the ventilatory pattern. We used "time motion" mode (M-mode) sonography to assess the changes in diaphragm kinetics induced by spirometry during quiet breathing.

METHODS

An M-mode sonographic study of the right diaphragm was performed before and during standard spirometry in eight patients without respiratory disease (age 34 to 68 yr).

RESULTS

During spirometry, the diaphragm inspiratory amplitude (DIA) increased from 1.34 +/- 0.18 cm to 1.80 +/- 0.18 cm (P = 0.007), whereas the diaphragmatic inspiratory (T1 diaph) increased from 1.27 +/- 0.15 to 1.53 +/- 0.23 sec, (P = 0.015, without change in diaphragmatic total time interval (Ttot diaph). Therefore, the diaphragm duty cycle (T1 diaph/Ttot diaph) increased from 38% +/- 1% to 44% +/- 4% (P = 0.023). The diaphragm inspiratory (DIV) and expiratory (DEV) motion velocity (P = 0.007).

CONCLUSION

M-mode sonography enabled us to demonstrate that the wearing of a nose clip and breathing through a mouthpiece and a pneumotachograph induce measurable changes in diaphragm kinetics.

[Delay of clinical recovery from paralysis induced by atracurium: comparison between orbicularis oculi and adductor pollicis]

OBJECTIVE

To compare with train-of-four stimulation the delays of the beginning of the spontaneous recovery of the orbicularis oculi and of the adductor pollicis after profound neuromuscular blockade with atracurium.

STUDY DESIGN

Prospective, comparative open study.

PATIENTS AND METHODS

Twenty-eight physical class ASA 1 and 2 patients under general anaesthesia (propofol, N2O, fentanyl) and profound neuromuscular blockade with atracurium. Train-of-four stimulation, every 10 s, of the ulnar nerve at the wrist (for assessing by tactile means the response of the adductor pollicis) and of the temporal branch of the facial nerve (for assessing visually the response of the orbicularis oculi). On each site, measurement of the delay between the end of the maintenance of deep neuromuscular blockade (last dose of atracurium) and the beginning of the recovery (first response to train-of-four stimulation).

RESULTS

In each case, the recovery of the orbicularis oculi began earlier than the recovery of the adductor pollicis (26 +/- 9 min vs 34 +/- 9 min, P < 0.001). The delays of recovery at each site were strongly correlated (r = 0.87; P < 0.001) but the time lag between the responses varied greatly: 1 to 21 min, mean: 8 +/- 5 min, coefficient of variation: 56.6%.

CONCLUSION

The orbicularis oculi should not be monitored alone for assessment of recovery from profound neuromuscular blockade by atracurium, as it predicts poorly the time of the recovery of the adductor pollicis.

The effect of positive end-expiratory pressure on respiratory resistive properties in anaesthetized paralysed humans

The respiratory resistive properties of the normal human respiratory system are volume-dependent. The overall flow resistance (Rmax,rs) can be partitioned into airway resistance (Raw) and the additional resistance (delta Rrs) which may result from the viscoelastic properties of the respiratory system, from inequality of time constants (pendelluft), or from both. Because positive end-expiratory pressure (PEEP) increases end-expiratory lung volume and may equalize ventilation within the lungs, the effect of PEEP on Raw, delta Rrs, and their sum (Rmax,rs) was assessed in anaesthetized surgical patients without evidence of lung disease. Fifteen men were studied during paralysis and isoflow isovolume mechanical ventilation, using the end-inflation occlusion method. Ten men were studied with incremental levels of PEEP, up to 16 cmH2O (Group A). Five men were studied without PEEP (Group B). In Group A, Rmax,rs did not change with PEEP. In contrast, Raw decreased and delta Rrs increased significantly. Moreover, there was a linear relationship between PEEP and the contribution of delta Rrs to Rmax,rs. In Group B, Rmax,rs, Raw and delta Rrs, and the contribution of delta Rrs to Rmax,rs did not change. In both groups, atropine elicited a decrease in Rmax,rs, linked to a decrease in Raw, without any notable effect on the static elastance of the respiratory system (Est,rs) or on delta Rrs. We conclude that the overall flow resistance was not affected by PEEP. In contrast, PEEP clearly modified the contribution of its two components. The decrease in Raw with PEEP could have resulted, at least in part, from modification in the basal vagal tone.

EFFECT OF FENTANYL ON VENTILATORY RESISTANCES DURING BARBITURATE GENERAL ANAESTHESIA

Fentanyl has been shown to increase the overall resistance to inspiratory flow of the ventilatory system (Rmax). Rmax is the sum of the airway resistance (Raw) and of the non-Newtonian resistance (delta R) which may result from the viscoelastic properties of the thoracic tissues, from inequalities of the regional time constants within the lung, or from both. A bronchoconstrictor challenge may increase the magnitude of variation in regional time constants. Thus, in order to describe the effect of fentanyl on the two components of Rmax, this study was performed, with the end-inflation occlusion method, during paralysis and mechanical ventilation in 10 normal men undergoing barbiturate anaesthesia for minor urological procedures. The patients were anaesthetized with methohexitone and paralysed with vecuronium. Before administration of fentanyl, delta R accounted for 56% of Rmax. Fentanyl 5 micrograms kg-1 elicited a significant increase in Rmax (+34.5%; P = 0.005) and a parallel increase in both Raw (+35.2%, P = 0.017) and delta R (+33.5%, P = 0.005). The increase in Raw, but not in delta R, was reversed by atropine, suggesting that the increase in these two components of Rmax was not linked. Thus fentanyl increased both components of Rmax, but the effects of fentanyl on Raw and delta R seemed to depend on different mechanisms.

Effect of resistive loads on pattern of respiratory muscle recruitment during exercise

In healthy subjects, we compared the effects of an expiratory (ERL) and an inspiratory (IRL) resistive load (6 cmH2O.l-1.s) with no added resistive load on the pattern of respiratory muscle recruitment during exercise. Fifteen male subjects performed three exercise tests at 40% of maximum O2 uptake: 1) with no-added-resistive load (control), 2) with ERL, and 3) with IRL. In all subjects, we measured breathing pattern and mouth occlusion pressure (P0.1) from the 3rd min of exercise, in 10 subjects O2 uptake (VO2), CO2 output (VCO2), and respiratory exchange ratio (R), and in 5 subjects we measured gastric (Pga), pleural (Ppl), and transdiaphragmatic (Pdi) pressures. Both ERL and IRL induced a high increase of P0.1 and a decrease of minute ventilation. ERL induced a prolongation of expiratory time with a reduction of inspiratory time (TI), mean expiratory flow, and ratio of inspiratory to total time of the respiratory cycle (TI/TT). IRL induced a prolongation of TI with a decrease of mean inspiratory flow and an increase of tidal volume and TI/TT. With ERL, in two subjects, Pga increased and Ppl decreased more during inspiration than during control suggesting that the diaphragm was the most active muscle. In one subject, the increases of Ppl and Pga were weak; thus Pdi increased very little. In the two other subjects, Ppl decreased more during inspiration but Pga also decreased, leading to a decrease of Pdi. This suggests a recruitment of abdominal muscles during expiration and of accessory and intercostal muscles during inspiration. With IRL, in all subjects, Ppl again decreased more, Pga began to decrease until 40% of TI and then increased.(ABSTRACT TRUNCATED AT 250 WORDS)