Intussusception through an ileostomy.
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Adult↗
Biomedical subjects
Henry Kwok
Publications and source records attributed to Henry Kwok.
Controlled trial of oronasal versus nasal mask ventilation in the treatment of acute respiratory failure.
OBJECTIVE: Noninvasive positive pressure techniques such as continuous and bilevel positive airway pressure avoid intubation and its attendant complications in selected patients with acute respiratory failure. However, mask intolerance remains a common cause for failure of noninvasive ventilatory techniques. The aim of our study was to assess patient tolerance of oronasal vs. nasal mask ventilation in acute respiratory failure. DESIGN: Randomized, controlled trial. SETTING: Emergency department or intensive care units at a university hospital. PATIENTS: Seventy patients with acute respiratory failure as evidenced by clinical or blood gas criteria. INTERVENTIONS: Patients randomly received either a disposable nasal or an oronasal mask (Respironics, Pittsburgh, PA) when they met study criteria. MEASUREMENTS AND MAIN RESULTS: Thirty-five patients were randomized into each arm of the study; most of the patients had acute cardiogenic pulmonary edema (48.6% of the nasal mask group and 42.8% of the facial mask group) or chronic obstructive airway disease (34.3% of the nasal mask group and 31.4% of the facial mask group). Baseline clinical characteristics of the two groups of patients were similar. Heart and respiratory rates and blood gases improved similarly for patients in both mask groups. Rates of intubation were also similar (eight in each group). However, mask intolerance was significantly higher in the nasal than the oronasal mask group (12 vs. 4, respectively, p=.023). Four patients in the nasal (11.4%) and two in the oronasal mask group (5.7%) died later during the hospitalization. The overall success rate tended to be greater in the oronasal (65.7%) than the nasal group (48.6%), but the difference was not statistically significant. CONCLUSION: Although both masks performed similarly with regard to improving vital signs and gas exchange and avoiding intubation, the nasal mask was less well tolerated than the oronasal mask in patients with acute respiratory failure.
Acute Disease↗
Acute applications of noninvasive positive pressure ventilation.
Noninvasive positive-pressure ventilation (NPPV) has been used increasingly to treat acute respiratory failure (ARF). The best indications for its use are ARF in patients with COPD exacerbations, acute pulmonary edema, and immunocompromised states. For these indications, multiple controlled trials have demonstrated that therapy with NPPV avoids intubation and, in the case of COPD and immunocompromised patients, reduces mortality as well. NPPV is used to treat patients with numerous other forms of ARF, but the evidence is not as strong for its use in those cases, and patients must be selected carefully. The best candidates for NPPV are able to protect their airway, are cooperative, and are otherwise medically stable. Success is optimized when a skilled team applies a well-fitted, comfortable interface. Ventilator settings should be adjusted to reduce respiratory distress while avoiding excessive discomfort, patient-ventilator synchrony should be optimized, and adequate oxygenation should be assured. The appropriate application of NPPV in the acute care setting should lead to improved patient outcomes and more efficient resource utilization.
Humans↗
Prenatal nicotine exposure increases apnoea and reduces nicotinic potentiation of hypoglossal inspiratory output in mice.
We examined the effects of in utero nicotine exposure on postnatal development of breathing pattern and ventilatory responses to hypoxia (7.4 % O2) using whole-body plethysmography in mice at postnatal day 0 (P0), P3, P9, P19 and P42. Nicotine delayed early postnatal changes in breathing pattern. During normoxia, control and nicotine-exposed P0 mice exhibited a high frequency of apnoea (f(A)) which declined by P3 in control animals (from 6.7 +/- 0.7 to 2.2 +/- 0.7 min(-1)) but persisted in P3 nicotine-exposed animals (5.4 +/- 1.3 min(-1)). Hypoxia induced a rapid and sustained reduction in f(A) except in P0 nicotine-exposed animals where it fell initially and then increased throughout the hypoxic period. During recovery, f(A) increased above control levels in both groups at P0. By P3 this increase was reduced in control but persisted in nicotine-exposed animals. To examine the origin of differences in respiratory behaviour, we compared the activity of hypoglossal (XII) nerves and motoneurons in medullary slice preparations. The frequency and variability of the respiratory rhythm and the envelope of inspiratory activity in XII nerves and motoneurons were indistinguishable between control and nicotine-exposed animals. Activation of postsynaptic nicotine receptors caused an inward current in XII motoneurons that potentiated XII nerve burst amplitude by 25 +/- 5 % in control but only 14 +/- 3 % in nicotine-exposed animals. Increased apnoea following nicotine exposure does not appear to reflect changes in basal activity of rhythm or pattern-generating networks, but may result, in part, from reduced nicotinic modulation of XII motoneurons.
Animals↗