Biomedical subjects

A Naveira

Publications and source records attributed to A Naveira.

7 recordsLinked to original sources

PubMed2001

Application of tracheal gas insufflation to acute unilateral lung injury in an experimental model.

In unilateral lung injury, application of global positive end-expiratory pressure (PEEP) may cause overdistension of normal alveoli and redistribution of blood flow to diseased lung areas, thereby worsening oxygenation. We hypothesized that selective application of tracheal gas insufflation (TGI) will recruit the injured lung without causing overdistension of the normal lung. In eight anesthetized dogs, left lung saline lavage was performed until Pa(O(2))/FI(O(2)) fell below 100 mm Hg. Then, the dogs were reintubated with a Univent single lumen endotracheal tube that incorporates an internal catheter to provide TGI. After injury, increasing PEEP from 3 to 10 cm H(2)O did not change gas exchange, hemodynamics, or lung compliance. Selective TGI, while keeping end-expiratory lung volume (EELV) constant, improved Pa(O(2))/FI(O(2)) from 212 +/- 43 to 301 +/- 38 mm Hg (p < 0.01) while Pa(CO(2)) and airway pressures decreased (p < 0.01). During selective TGI, reducing tidal volume to 5.2 ml/kg while keeping EELV constant, normalized Pa(CO(2)), did not affect Pa(O(2))/FI(O(2)), and decreased end-inspiratory plateau pressure from 16.6 +/- 1.0 to 11.9 +/- 0.5 cm H(2)O (p < 0.01). In unilateral lung injury, we conclude that selective TGI (1) improves oxygenation at a lower pressure cost as compared with conventional mechanical ventilation, (2) allows reduction in tidal volume without a change in alveolar ventilation, and (3) may be a useful adjunct to limit ventilator-associated lung injury.

Animals↗

PubMed2001

Epidural washout with high volumes of saline to accelerate recovery from epidural anaesthesia.

BACKGROUND: Prolonged postoperative blockade can follow neuraxial blocks for short surgical procedures. We investigated whether washout with a high volume of saline through an epidural catheter could provide a faster recovery after epidural anaesthesia. METHODS: Thirty patients were randomly assigned to a control group (no washout), to group 2x (epidural washout with twice the volume of 2% mepivacaine) and group 4x (epidural washout with four times that volume). RESULTS: Recovery times from sensory blockade at L2 were 151+/-24, 122+/-29 and 116+/-24 min for control, 2x and 4x groups respectively. Significant differences were found in both saline groups when compared with control group, but not between group 2x and group 4x. No differences were found concerning motor blockade. One patient in group 4x demonstrated signs of intracranial hypertension. Mepivacaine plasma concentrations were increased by saline washout in group 4x. CONCLUSIONS: Epidural washout with a high volume of saline can not be recommended since no clinically significant reduction in the recovery time can be achieved without risk.

Anesthesia Recovery Period↗

PubMed2001

Relative roles of vascular and airspace pressures in ventilator-induced lung injury.

OBJECTIVE: To determine whether elevations in pulmonary vascular pressure induced by mechanical ventilation are more injurious than elevations of pulmonary vascular pressure of similar magnitude occurring in the absence of mechanical ventilation. DESIGN: Prospective comparative laboratory investigation. SETTING: University research laboratory. SUBJECTS: Male New Zealand white rabbits. INTERVENTIONS: Three groups of isolated, perfused rabbit lungs were exposed to cyclic elevation of pulmonary artery pressures arising from either intermittent positive pressure mechanical ventilation or from pulsatile perfusion of lungs held motionless by continuous positive airway pressure. Peak, mean, and nadir pulmonary artery pressures and mean airway pressure were matched between groups (35, 27.4 +/- 0.74, and 20.8 +/- 1.5 mm Hg, and 17.7 +/- 0.22 cm H2O, respectively). MEASUREMENTS AND MAIN RESULTS: Lungs exposed to elevated pulmonary artery pressures attributable to intermittent positive pressure mechanical ventilation formed more edema (6.8 +/- 1.3 vs. 1.1 +/- 0.9 g/g of lung), displayed more perivascular (61 +/- 26 vs. 15 +/- 13 vessels) and alveolar hemorrhage (76 +/- 11% vs. 26 +/- 18% of alveoli), and underwent larger fractional declines in static compliance (88 +/- 4.4% vs. 48 +/- 25.1% decline) than lungs exposed to similar peak and mean pulmonary artery pressures in the absence of tidal positive pressure ventilation. CONCLUSIONS: Isolated phasic elevations of pulmonary artery pressure may cause less damage than those occurring during intermittent positive pressure mechanical ventilation, suggesting that cyclic changes in perivascular pressure surrounding extra-alveolar vessels may be important in the genesis of ventilator-induced lung injury.

Animals↗

PubMed2001

Selective tracheal gas insufflation during partial liquid ventilation improves lung function in an animal model of unilateral acute lung injury.

OBJECTIVE: During unilateral lung injury, we hypothesized that we can improve global lung function by applying selective tracheal gas insufflation (TGI) and partial liquid ventilation (PLV) to the injured lung. DESIGN: Prospective, interventional animal study. SETTING: Animal laboratory in a university hospital. SUBJECTS: Adult mixed-breed dogs. INTERVENTIONS: In six anesthetized dogs, left saline lung lavage was performed until PaO(2)/FiO(2) fell below 100 torr (13.3 kPa). The dogs were then reintubated with a Univent single-lumen endotracheal tube, which incorporates an internal catheter to provide TGI. In a consecutive manner, we studied 1) the application of 10 cm H(2)O of positive end-expiratory pressure (PEEP); 2) instillation of 10 mL/kg of perflubron (Liquivent) to the left lung at a PEEP level of 10 cm H(2)O (PLV+PEEP 10 initial); 3) application of selective TGI (PLV+TGI) while maintaining end-expiratory lung volume (EELV) constant; 4) PLV+TGI at reduced tidal volume (VT); and 5) PLV+PEEP 10 final. MEASUREMENTS AND MAIN RESULTS: Application of PLV+PEEP 10 initial did not change gas exchange, lung mechanics, or hemodynamics. PLV+TGI improved PaO(2)/FiO(2) from 189 +/- 13 torr (25.2 +/- 1.7 kPa) to 383 +/- 44 torr (51.1 +/- 5.9 kPa) (p <.01) and decreased PaCO(2) from 55 +/- 5 torr (7.3 +/- 0.7 kPa) to 30 +/- 2 torr (4.0 +/- 0.3 kPa) (p <.01). During ventilation with PLV+TGI, reducing VT from 15 mL/kg to 3.5 mL/kg while keeping EELV constant decreased PaO(2)/FiO(2) to 288 +/- 49 torr (38.4 +/- 6.5 kPa) (not significant) and normalized PaCO(2). At this stage, end-inspiratory plateau pressure decreased from 19.2 +/- 0.7 cm H(2)O to 13.6 +/- 0.7 cm H(2)O (p <.01). At PLV+PEEP 10 final, measurements returned to those observed at previous baseline stage (PLV+PEEP 10 initial). CONCLUSIONS: During unilateral lung injury, PLV with a moderate PEEP did not improve oxygenation, TGI superimposed on PLV improved gas exchange, and combination of TGI and PLV allowed a 77% reduction in VT without any adverse effect on PaCO(2).

Animals↗

PubMed1999

[Obstetric anesthesia/analgesia in Spain. Study notes on its historical evolution during the 1st half of this century].

This historical review of obstetric analgesia-anesthesia in Spain covers the first half of the twentieth century. Following usual practice for researching medical history, we have performed an exhaustive review of Spanish medical literature published during the study period, followed by classification, study and critical analysis. We found that the first half of the century saw considerable change in the application of analgesic-anesthetic techniques for childbirth and obstetric procedures, indicating that practitioners were far from apathetic as had been obstetricians of the second half of the nineteenth century, who generally rejected any type of analgesia for use during labor and birth. The numerous techniques in vogue during that period under study are described, although analgesia-anesthesia by inhaled ether and chloroform was undoubtedly the most widely used by obstetricians until well into the 1950's.

Analgesia, Obstetrical↗

PubMed1998

[Perforation and entrapment of an intra-aortic balloon: a complication related to the duration of implantation].

A 69-year-old man was admitted to the Intensive Care Recovery Unit after heart surgery, carrying an intra balloon counterpulsation (IABCP) device inserted percutaneously days before surgery to provide hemodynamic support and which was still required after surgery. Fifteen days after insertion, blood was observed in the safety chamber. Surgical removal of the catheter was required when attempts to remove it manually failed. The balloon was seen to be perforated and clotted blood was found inside. We believe that long-term maintenance of IABCP carries high risk of perforation and entry of blood, which will clot, as well as of catheter entrapment unless removal is prompt.

Aged↗

PubMedDate not supplied

[Continuous renal replacement therapy: management of acute renal insufficiency in critical care units].

Acute renal insufficiency is characterized by a sudden decrease in renal function. Various causes are implicated and the physiopathological mechanisms are quite complex. When kidney failure is associated with other organ or system failure, the patient is usually treated in an intensive care unit. Such "critical status" patients are characterized by severe cardiovascular, respiratory and metabolic unstability that may make conventional methods of dialysis (intermittent hemodialysis and peritoneal dialysis) impossible or inadvisable. Continuous methods of renal replacement include 24-hour extracorporeal blood filtration for an indefinite period of time. Such aspects of renal function as electrolyte regulation of nitrogenated products, inflammatory mediators and so forth are replaced or supplemented by various continuous modes available. In this review we discuss the functions and indications for the continuous renal replacement techniques available. The components of each technique are studied exhaustively with a view to obtaining benefit.

Acute Kidney Injury↗