Anaesthesia and intensive care
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Anaesth Intensive Care · Aug 2001
Relationship between work of breathing provided by a ventilator and patients' inspiratory drive during pressure support ventilation; effects of inspiratory rise time.
Inspiratory drive and work of breathing provided by a ventilator (WOBv) during pressure support ventilation (PSV) were examined in 15 patients. At PSV 10 and 15 cm H2O during CPAP 5 cm H2O, patients with low P0.1 (<4.2 cm H2O, n=9) showed WOBv 0.57 and 0.92 J/l, those with high P0.1 (>4.2 cm H2O, n=6) showed 0.31 and 0.62 J/l respectively. WOBv was smaller and pressure-time product of oesophageal pressure (PTP) was significantly larger in high P0.1 patients. ⋯ Compared with higher PSV, shorter IRT reduced PTP more. In conclusion, WOBv decreased as inspiratory drive increased due to inability to increase inspiratory flow. Increasing initial inspiratory flow was more effective than raising PSV to preserve inspiratory assistance of PSV at high inspiratory drive.
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Anaesth Intensive Care · Jun 2001
Randomized Controlled Trial Clinical TrialPCA ketamine and morphine after abdominal hysterectomy.
Following a standardized general anaesthetic for total abdominal hysterectomy, patients received either patient controlled analgesia (PCA) with morphine 1 mg/ml (group M, n = 33) or morphine 1 mg/ml plus ketamine 2 mg/ml (group K, n = 37) for 48 hours in a randomized, double-blind fashion. In 43 women the area of allodynia around the scar was mapped as a measure of the degree of central sensitization. A significant reduction in the area of allodynia was found in those receiving ketamine with morphine (42 cm2 [interquartile range (IQR) 57] compared with 57 cm2 [IQR 82] z = -2.0, P = 0.04) in those receiving morphine alone. ⋯ Patients in group K were more likely to require PCA for a shorter period than those in group M (median 40 hours, IQR 26 versus 48 hours IQR 7). Ten patients in group K were withdrawn because of side-effects (dysphoria n = 4, nausea n = 2, pruritus n = 4) compared with one in group M (nausea n = 1) (P = 0.006). The potential usefulness of ketamine after hysterectomy was offset by a high incidence of adverse effects and a lack of opioid-sparing effects, such that combined intravenous ketamine and morphine PCA as used in this study cannot be recommended for routine care.
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Anaesth Intensive Care · Jun 2001
Randomized Controlled Trial Comparative Study Clinical TrialBlind orotracheal intubation with the intubating laryngeal mask versus fibreoptic guided orotracheal intubation with the Ovassapian airway. A pilot study of awake patients.
In a randomized, prospective pilot study, we compared awake blind orotracheal intubation using the intubating laryngeal mask airway (blind-ILM) with awake fibreoptic-guided orotracheal intubation using an Ovassapian airway (FOS-OA). Fifty-four patients (ASA 1 to 3, aged 18 to 85 years) requiring awake intubation for elective surgery were randomly allocated by coin toss into two groups: 31 patients were intubated blindly through the ILM (blind-ILM) and 23 were intubated using fibreoptic guidance through the Ovassapian airway (FOS-OA). Sedation to a target clinical end-point (spontaneous eye-closing, but responsive to verbal command) was obtained with fentanyl/midazolam and a cricothyroid puncture was performed with 3 ml lignocaine 4%. ⋯ There were no clinically significant differences in blood pressure or heart rate between groups. Compared with baseline values, there was no cardiovascular response to intubation in either group. We conclude that the blind-ILM and FOS-OA techniques have similar success rates and cardiovascular responses, but intubation is slightly quicker with the blind-ILM technique.
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Anaesth Intensive Care · Jun 2001
Randomized Controlled Trial Comparative Study Clinical TrialIntubation through intubating laryngeal mask with and without a lightwand: a randomized comparison.
The combined use of a lightwand and the intubating laryngeal mask airway (ILMA) was compared with the use of the ILMA alone to determine whether the combination was a more efficient method of endotracheal intubation. One hundred healthy patients were randomly assigned to two groups. After induction of anaesthesia, Group A patients were intubated blindly through the ILMA while in Group B, intubation was guided by a lightwand. ⋯ Intubations were successful in all patients, but the mean endotracheal intubation time was longer in Group A than in Group B (38.3 +/- 10.4 s versus 26.4 +/- 9.1 s, P < 0.001). The number of patients who needed one or more manoeuvres was significantly higher in Group A than in Group B (76% versus 42%, P = 0.001). We conclude that the lightwand is a useful adjunct in endotracheal intubation through an ILMA.