Effects of spinal needle type on lateral distribution of 0.5% hyperbaric bupivacaine

To evaluate the influence of needle type on the lateral distribution of 0.5% hyperbaric bupivacaine, 30 patients undergoing lower limb surgery were placed in the lateral position with the side to be operated on dependent and underwent dural puncture by either a 25-gauge Whitacre (n = 15) or a 25-gauge Quincke (n = 15) spinal needle. The needle hole was turned toward the dependent side and 8 mg of 0.5% hyperbaric bupivacaine was injected over 30 s. The lateral position was maintained for 15 min while a blind observer recorded loss of pinprick sensation and degree of motor block on both the dependent and nondependent sides every 5 min until regression of motor block by 1 degree on the dependent side. Thirty minutes after the patients were placed in the supine position, unilateral sensory block was observed in 10 patients in the Whitacre group (66%) and in 2 patients in the Quincke group (13%) (P < 0.05). No differences in the rate of unilateral motor block were observed (73% and 40% in Whitacre and Quincke groups, respectively). We conclude that when a small dose of 0.5% hyperbaric bupivacaine is injected slowly into patients in the lateral position for 15 min, the Whitacre spinal needle provides a more marked differential block of sensory nerve roots between dependent and nondependent sides compared with the Quincke needle.

IMPLICATIONS

Because unilateral spinal anesthesia can be advantageous for lower limb surgery, we evaluated the influence of the Whitacre and Quincke spinal needle types on the lateral distribution of small-dose 0.5% hyperbaric bupivacaine injected slowly into adult patients.

A clinical comparison between needle-through-needle and double-segment techniques for combined spinal and epidural anesthesia

BACKGROUND AND OBJECTIVES

The goal of the present investigation was to compare the double-segment and the needle-through-needle techniques for combined spinal and epidural anesthesia (CSE) in a prospective, randomized, blinded study.

METHODS

With Ethical Committee approval and patient's consent, 120 patients were randomized to receive CSE by the needle-through-needle (SST; n=60) or the double-segment technique (DST; n=60). A blind observer measured the time required from skin disinfection to readiness for surgery (loss of pinprick sensation up to T10), failure of dural puncture, need for epidural top-up before surgery, patient acceptance, and occurrence of complications.

RESULTS

No neurologic complications were observed in either group. Time to readiness for surgery was 22.7+/-8.2 minutes in the SST group and 29.8+/-8.31 minutes in the DST one (P < .001). Dural puncture was unsuccessful in three patients in the SST group (5%) and in one patient in the DST group (1.6%) (ns); inadequate spread of spinal anesthesia was observed in five patients in the SST group (8.3%) and in eight patients in the DST group (13.3%) (ns). No difference in the incidence of hypotension, postdural puncture headache, and back pain was observed between the two groups. Acceptance of anesthetic procedure was better in the SST (85%) than in the DST group (66.6%) (P < .05).

CONCLUSIONS

The needle-through-needle technique for CSE requires less time, has no greater failure rate, and results in greater patient satisfaction than the double-segment technique. The use of a spinal needle with an adjustable locking mechanism and protruding up to 15 mm beyond the Tuohy needle improved successful spinal block in the needle-through-needle technique compared with previous reports.

Incidence of hypotension and bradycardia during integrated epidural/general anaesthesia. An epidemiologic observational study on 1200 consecutive patients. Italian Study Group on Integrated Anaesthesia

BACKGROUND

Combined epidural/general anaesthesia might theoretically emphasise the cardiovascular effects of epidural block alone. The goal of the present investigation was to evaluate the incidence of both hypotension and bradycardia during integrated epidural/general anaesthesia in a multicentric, observational study.

METHODS

The incidence of clinical hypotension (systolic arterial blood pressure decrease by 30% or more from baseline), and bradycardia (heart rate < 50 beats/min) and other side effects have been evaluated in 1200 consecutive patients receiving integrated epidural/general anaesthesia. The time from induction of epidural anaesthesia to induction of general anaesthesia was considered as preoperative; while the time after general anaesthesia induction was considered as intraoperative.

RESULTS

Preoperatively hypotension developed in 85 patients (2.8%), and bradycardia in 54 patients (4.5%). Intraoperatively, hypotension was observed in 380 patients (31.6%), and bradycardia in 153 patients (12.7%). Hypotension and bradycardia were not influenced by the type of surgical procedure, the type of maintenance of general anaesthesia (inhalational versus total intravenous general anaesthesia) and the level of epidural block (lumbar versus thoracic); but they were more frequent in patients with ASA physical status II and III-IV compared to patients with ASA physical status I (p < 0.05). Prophylactic volume preload decreased the incidence of hypotension from 41.5% to 22.4% (p < 0.0001), while prophylactic atropine before epidural block did not affect the incidence of bradycardia. Patients receiving epidural clonidine showed an increased incidence of intraoperative bradycardia compared to those who did not receive it (p < 0.0001).

DISCUSSION

Randomized, controlled studies should be advocated in order to compare the incidence of hypotension and bradycardia during integrated anaesthesia and during epidural block alone. Our results demonstrated that the use of integrated epidural/general anaesthesia produces an incidence of perioperative hypotension and bradycardia similar to that reported when central blocks are used alone.

Rapid turnover proteins in critically ill ICU patients. Negative acute phase proteins or nutritional indicators?

BACKGROUND

Rapid turnover proteins are often used as metabolic indicators in patients receiving nutritional therapy. However, their plasmatic concentration can be influenced by activation of acute phase reaction due to stress. The aim of this prospective, observational study was to evaluate changes of positive and negative acute phase proteins in mechanically ventilated ICU patients with acute stress.

METHODS

Plasmatic concentrations of prealbumin (PRA), retinol-binding protein (RBP), c-reactive protein (CRP) as well as resting energy expenditure (REE) and nitrogen balance were measured in thirty ICU patients before starting nutritional support (Baseline) and then after 3 and 8 days of parenteral nutrition (TPN).

RESULTS

Plasmatic concentrations of CRP were high at baseline and did not change (p = 0.47), while RBP and PRA were low and progressively increased during the study (p = 0.0001 and p = 0.004). Percentage changes from baseline of both PRA and RBP were significantly correlated with nitrogen balance (p = 0.01 and p = 0.009); while no significant correlation was observed between changes of rapid turnover proteins and CRP (p = 0.72 and p = 0.10).

CONCLUSIONS

All the variables involved in the study are known to be influenced by both metabolic state and resolution of inflammation. However, the observed changes of rapid turnover proteins significantly correlate with nitrogen balance in the face of a persistent inflammation, as documented by CRP plasmatic concentrations. This suggests that RBP and PRA monitoring may be used as complement clinical evaluation of nutritional therapy also in ICU patients with ongoing inflammation.

Block distribution and cardiovascular effects of unilateral spinal anaesthesia by 0.5% hyperbaric bupivacaine. A clinical comparison with bilateral spinal block

BACKGROUND

A low dose of hyperbaric local anaesthetic solution, pencil point needle and slow speed of intrathecal injection have been reported to obtain a unilateral distribution of spinal anaesthesia. This should also minimize cardiovascular effects of spinal block. The aim of this prospective, randomized, parallel group study was to evaluate cardiac performance during unilateral subarachnoid block and to compare it with that produced by standard bilateral spinal anaesthesia.

METHODS

With Ethic Committee approval and patients' consent we studied 30 ASA I-II patients scheduled for one leg surgery. Dural puncture was performed by 25-G Whitacre needle with patients lying in the lateral position and the side to be operated on dependent. Patients then randomly received 8 mg of 0.5% hyperbaric bupivacaine injected over 80 sec with needle hole orientated towards the dependent side (Unilateral, n = 15), or 15 mg of the same solution injected over 6 sec with needle bevel cranially directed (Control, n = 15). Only patients of the Unilateral group remained in the lateral position for 15 min. Noninvasive Arterial blood pressure, heart rate, stroke volume index and cardiac index were measured before spinal block (baseline) and then at 5, 15, 30 and 45 min; while sensory and motor blocks were evaluated at 15, 30 and 45 min on both sides.

RESULTS

Unilateral spinal anaesthesia was observed in 11 patients of the Unilateral group (73%). Three patients of the Control group (20%) required colloids for intraoperative hypotension. Mean arterial blood pressure and heart rate decreased from baseline only in the Control group (p = 0.001 and p = 0.0003 respectively), while heart rate was decreased in Control even when compared to Unilateral group (p = 0.01). The stroke volume index was unchanged in the two groups (p = 0.22), while the cardiac index showed a 15-20% decrease from baseline in Control group (p = 0.001), with a significant decrease at 30 and 45 min when compared to Unilateral (p = 0.01).

DISCUSSION

The use of 8 mg of 0.5% hyperbaric bupivacaine slowly injected through a directional needle provided a spinal block relatively restricted to the operative side with minimal effects on cardiovascular homeostasis.

Comparison between epidural infusion of fentanyl/bupivacaine and morphine/bupivacaine after orthopaedic surgery

PURPOSE

To compare epidural infusions of bupivacaine-fentanyl and bupivacaine-morphine mixtures for postoperative pain relief after total hip replacement.

METHODS

In a prospective, randomized, double-blind study, 30 ASA physical status I-II patients undergoing total hip replacement were studied. Anaesthesia was provided by combined general/epidural anaesthesia without epidural opioids. Postoperative epidural analgesia was by continuous infusion of bupivacaine 0.125% (4 ml.hr-1) with either 0.05 mg.ml-1 morphine (morphine, n = 15) or 0.005 mg.ml-1 fentanyl (fentanyl, n = 15). Visual analogue pain scale (VAS), sedation (four-point scale), respiratory rate, pulse oximetry, rescue analgesics and supplemental oxygen were recorded by a blind observer at 1, 3, 6, 9, 12 and 24 hr after surgery.

RESULTS

No differences in pain relief, sedation, or non-respiratory side effects were observed between the two groups. Rescue analgesics were required in three patients in the fentanyl group (20%) and in two receiving morphine (13.3%) (P:NS). Two patients in the fentanyl group and three in the morphine group required oxygen due to SpO2 < 90% (P:NS). Both opioid/bupivacaine mixtures decreased haemoglobin oxygen saturation compared with preoperative values. The mean +/- SD SpO2 values measured at 3, 6, 12 and 24 hr were 94.4 +/- 1, 92.6 +/- 0.9, 92 +/- 0.8, and 92.8 +/- 1 in the morphine group, 95.3 +/- 0.5, 95 +/- 0.5, 94.6 +/- 1.2, and 95.6 +/- 1 in the fentanyl group (P < 0.05).

CONCLUSION

Continuous epidural infusion of bupivacaine-morphine or bupivacaine-fentanyl mixtures provided similar pain relief. Patients receiving morphine showed a more marked decrease in SpO2 than those receiving fentanyl. However, the average SpO2 remained > 90% in both groups.

Unexpected cardiac arrest during epidural anaesthesia

We reported the case of sudden asystole requiring close chest cardiac massage in a 56-yrs-old health man receiving epidural anaesthesia for elective transurethral resection of bladder tumour (TURBT). The anaesthetic procedure was performed in a regional-block-room. Cardiac arrest developed few minutes after local anaesthetic injection, before the patient has been transferred to the operating room. The importance of patient monitoring during regional anaesthesia must be further on pointed out, especially when the anaesthetic procedure is performed out of the operating room (e.g. in the recovery room or in a "regional-block-room").

Cardiovascular effects of two different regional anaesthetic techniques for unilateral leg surgery

BACKGROUND

Cardiovascular function was assessed in 20 ASA I-II patients, scheduled for elective orthopaedic surgery with tourniquet in order to compare the haemodynamic changes induced by unilateral spinal anaesthesia and combined sciatico-femoral nerve block.

METHODS

After baseline measurement of cardiovascular parameters, patients were randomized to receive unilateral spinal anaesthesia or combined sciatico-femoral nerve block. Spinal anaesthesia was obtained by 8 mg of hyperbaric bupivacaine 0.5% slowly injected (speed=0.02 ml s[-1]) through a 25-G Whitacre spinal needle with the bevel orientated towards the dependent side and patients lying on their operated side for 15 min (group S, n=10). Combined sciatico-femoral nerve block was obtained by 7 mg kg(-1) of mepivacaine 2% (group NB, n=10). Haemodynamic variables were recorded 5, 10, 15, and 30 min after anaesthetic injection before surgery was started.

RESULTS

Anthropometric data, duration of surgery and acceptability of anaesthetic techniques were similar in the 2 groups. In 8 patients of group S, spinal block was restricted to the operated side (pinprick test and Bromage scale), while the other 2 patients developed bilateral spinal block after being turned supine. NB patients showed no haemodynamic changes during the study, whereas patients in group S showed a small but significant decrease of mean arterial blood pressure (P<0.002 vs baseline and P<0.04 vs NB), cardiac index (P<0.01 vs baseline and P<0.01 vs NB), and stroke volume index (P<0.01 vs baseline and P<0.01 vs NB).

CONCLUSION

Both sciatico-femoral and unilateral spinal blockade provide adequate anaesthesia for unilateral leg surgery with tourniquet. The former technique affects cardiovascular performance less than the latter one.

A transient neurological deficit following intrathecal injection of 1% hyperbaric bupivacaine for unilateral spinal anaesthesia

We describe a case of transient neurological deficit that occurred after unilateral spinal anaesthesia with 8 mg of 1% hyperbaric bupivacaine slowly injected through a 25-gauge pencil-point spinal needle. The surgery and anaesthesia were uneventful, but 3 days after surgery, the patient reported an area of hypoaesthesia over L3-L4 dermatomes of the leg which had been operated on (loss of pinprick sensation) without reduction in muscular strength. Sensation in this area returned to normal over the following 2 weeks. Prospective multicentre studies with a large population and a long follow-up should be performed in order to evaluate the incidence of this unusual side effect. However, we suggest that a low solution concentration should be preferred for unilateral spinal anaesthesia with a hyperbaric anaesthetic solution (if pencil-point needle and slow injection rate are employed), in order to minimize the risk of a localized high peak anaesthetic concentration, which might lead to a transient neurological deficit.

Chromosomal fragility in the cancer-prone disease xeroderma pigmentosum preferentially involves bands relevant for cutaneous carcinogenesis

Spontaneous and folate-induced chromosomal fragility was analyzed in peripheral blood lymphocytes from 6 patients affected by the cancer-prone disease xeroderma pigmentosum (XP), from the parents of 4 of the patients, and from 12 normal subjects. All XP patients were defective in nucleotide-excision repair; 4 belonged to group C and 1 each to groups A and D. A tendency toward increased spontaneous chromosomal fragility was observed in the XP family members, and lesions indicating substantial chromosomal damage, which were not observed in any healthy donors, were frequently found. The spontaneous lesion sites in lymphocytes from homozygous and heterozygous carriers of XP defects appeared to be significantly associated with those observed in normal skin fibroblasts from the same subjects. These XP spontaneous fragility sites showed a statistically significant association with the rearrangement breakpoints reported in skin pre-tumoral and tumoral lesions from normal and unrelated XP donors. Under conditions of folate deprivation, the chromosomal fragility level, the pattern and the frequency of expression of fragile sites in XP patients and in their parents were similar to normal. However, XP patients generally showed a higher susceptibility to breakage at sites described as mutagen and carcinogen targets.

Treatment of severe acidemia in a young woman affected by diabetic ketoacidosis

The case of a 32-year-old woman admitted to Hospital for diabetic coma (GCS 8), with arterial blood pH below usually reported vital range, is described. After First Aid admittance an arterial blood gas analysis adjusted for patient's temperature showed PaO2 10.77 kPa, PaCO2 7.8 kPa, pH 6.52, HCO3 5 mmol/L, BE-34.9. A significant increase of lactate and butyrate concentration was also found. The patient was intubated and breathing was assisted for a 60 hour period after ICU admission, while acidemia was treated by THAM and bicarbonate associated to potassium i.v. infusion (infusions were titrated on acid-base and electrolyte concentration direct monitoring). After progressive neurological and biochemical improvement, 7 days after ICU admission the patient was moved to an Internal Medicine department. This case demonstrated that during diabetic ketoacidosis, despite very low pH (below reported vital range), an invasive intensive treatment could give complete cure without neurological sequelae.

Chromosomal instability and telomere length variations during the life span of human fibroblast clones

Growth characteristics, karyotype changes, and telomere length variations were analyzed during the life span of 12 anchorage-independent clones isolated from a xeroderma pigmentosum fibroblast strain. After an initial period of comparable active growth, all the clones showed a decline in the growth rate and finally entered a phase of replicative senescence; however, the number of population doublings and the time required to enter senescence varied among the clones. Repeated cytogenetic analyses during culture propagation showed the appearance of chromosome anomalies, mainly telomeric association (tas) and unbalanced translocations. In all the clones the percentage of abnormal mitoses increased with culture passage, but reached different levels (from less than 10% to about 100%). This finding indicates that the replicative block may be associated with differently altered cytogenetic patterns. Specific chromosome arms (5p, 16q, 19q, and 20q) were preferentially involved in tas, suggesting that alterations in chromosome ends may occur which predispose to fusion. In some clones it was possible to demonstrate the origin of marker chromosomes from the evolution of tas. Telomere length analysis by Southern blotting on DNA samples prepared from 7 clones and from the parental cell lines showed that the terminal restriction fragment (TRF) profiles were homogeneous in senescent parental cells and in the clones during the last part of their life in culture, regardless of the degree of karyotype abnormalities. The homogeneity of the TRF profiles supports the hypothesis of a critical telomere length at senescence.

Active warming, not passive heat retention, maintains normothermia during combined epidural-general anesthesia for hip and knee arthroplasty

STUDY OBJECTIVE

to compare passive heat retention by low-flow anesthesia, alone and with additional thermal insulation by reflective blankets, with forced-air warming preventing intraoperative hypothermia during combined epidural-general anesthesia.

DESIGN

Randomized, controlled study.

SETTING

Inpatient anesthesia at a university department of orthopedic surgery.

PATIENTS

30 ASA physical status I and II patients, who were scheduled for elective hip or knee arthroplasty and were free from systemic disease.

INTERVENTIONS

Patients received epidural block up to T10 by alkalinized lidocaine 2%, and then were administered standard general anesthesia by means of low-flow rebreathing system (fresh gas flow = 1 L/min). All procedures started between 8 and 10 AM, and operating room (OR) temperature was maintained between 21 degrees and 23 degrees C, with relative humidity ranging between 40% and 45%. For heat retention or warming therapy, patients received either low-flow anesthesia only (control, n = 10), low-flow anesthesia with additional reflective blankets (blanket, n = 10), or low-flow anesthesia with active forced-air warming (forced-air, n = 10). Tympanic temperature was measured at OR arrival (baseline); immediately following general anesthesia induction; 30, 60, 90, and 120 minutes from general anesthesia induction; and at the end of surgery.

MEASUREMENTS AND MAIN RESULTS

Duration of anesthesia, invasiveness of surgery, and baseline core temperature were similar in the three groups. Core temperature decreased in all the three groups 30 minutes after general anesthesia induction compared with baseline (p < 0.01); afterwards, it progressively decreased in the control and blankets groups (p = 0.004), with a reduction from baseline values measured at the end of surgery of 2.0 degrees C and 1.6 degrees C, respectively. In the forced-air group, after the initial significant decrease (p = 0.01 vs. baseline), core temperature progressively increased to 35.8 +/- 0.6 degrees C, which was similar to preoperative values and significantly higher than either the control or blankets groups (p = 0.004).

CONCLUSIONS

During combined epidural-general anesthesia for elective hip and knee arthroplasty, passive heat retention by means of low-flow anesthesia alone and in combination with reflective blankets is ineffective in maintaining intraoperative normothermia and definitely inferior to active forced-air warning.

[Perioperative thermal homeostasis. A duty of the anesthesiologist]

Anaesthesia, surgical procedures and operating room temperature can deeply alter the human thermoregulatory system. Unexpected and sometimes serious perioperative complications can occur. Many studies have been carried out in order to describe and evaluate the detrimental effects produced by different anaesthesia procedures (whether by general, regional or integrated anaesthesia) on thermic homeostasis. More recently it has also been reported that perioperative hypothermia significantly affects patients' outcome, increasing intraoperative blood losses, incidence of postoperative wound infection, and hospital stay. Italian anaesthetists have still a poor consideration about intraoperative body temperature monitoring and patients' warming as basic important skills for a better anaesthesiologic patients management. According with the literature, we do believe that this is not a right opinion. The purpose of the present paper would be to point out the most important knowledges concerning thermic homeostasis management, in order to increase anaesthesiologist's awareness in this essential field of patients perioperative care.

Telomeric fusions in cultured human fibroblasts as a source of genomic instability

In a human fibroblast clone we studied the evolution, during culture propagation, of a dicentric chromosome consisting of the end-to-end association of the short arm of chromosome 5 and the long arm of chromosome 16. Dual-color fluorescence in situ hybridization (FISH) with painting probes allowed us to define the structure of a variety of derivative chromosomes and to identify the mechanisms by which they originated. Asymmetric interchanges involving the intercentromeric region of the dicentric, bridge-breakage-fusion events, or breaks followed by sister chromatid fusion, originate unstable hetero- or homodicentric chromosomes with deletion or duplication; breakages not followed by reunion, or intradicentric recombination, presumably originate stable rearranged monocentric chromosomes. The variety of the derivatives is extremely large because the observed events may involve any site of the intercentromeric region, although the majority of them occurs after a break in 16qh. The results of this investigation document the evolution through successive steps of a telomeric fusion, a chromosome anomaly frequently observed in tumor and senescent cells. They also demonstrate that in cultured cells of normal origin, starting with this anomaly, various chromosomal mechanisms may produce translocations, duplications, and deletions. The karyotype instability produced by a telomeric fusion can be relevant for carcinogenesis because it may generate genetic changes critical in the multistep process of transformation.

Arterial to end-tidal carbon dioxide gradient and physiological dead space monitoring during general anaesthesia: effects of patients' position

METHODS

One hundred and five ASA I-II patients, scheduled for elective surgical procedures were studied in order to evaluate the effect of different surgical postures on physiological pulmonary dead space (VDphys/ VT) and arterial to end-tidal carbon dioxide gradient [P(a-Et)CO2]. Patients were divided into four groups according to their position on the operating table: supine position (acting as control group, n = 33), 20 degree Trendelenburg position (n = 24), lateral position (n = 24) and prone position with convex saddle frame (n = 24). Physiologic dead space was measured using Enghoff modification of Bohr equation. Arterial CO2 partial pressure was measured by blood gas analysis and end tidal CO2 was measured by means of an infrared CO2 analyser. All measurements were performed 20 minutes after general anaesthesia induction, with patients mechanically ventilated by a constant inspiratory flow (TV = 8 ml kg-1, RR = 10-14, EIP = 10%) in order to reach a steady state end tidal CO2 ranging between 32 and 36 mmHg; afterwards surgery started.

RESULTS

Arterial blood pressure showed a mean decrease of about 5-10% compared to baseline values, but no significant differences in arterial pressure decrease were found between the four groups. A significant VDphys/VT increase in postures other than supine was observed, unless it was statistically significant in lateral and prone position only; while P(a-Et)CO2 was higher in all postures compared to supine. Changes of intrapulmonary gas and blood distribution due to patients' posture are probably responsible for the observed physiologic dead space and CO2 gradient differences.

CONCLUSIONS

In conclusion, the clinical practice of predicting PaCO2 from EtCO2 must be tempered by recognition of the potential magnitude of P(a-Et)CO2 gradient, which is higher than normal during general anaesthesia and further increased when positioning the patient other than supine.

Cardiac performance during unilateral lumbar spinal block after crystalloid preload

PURPOSE

The haemodynamic effects of crystalloid preload were evaluated in a randomised blind study in 20 ASA status I-II, 50-80 yr-old patients, undergoing unilateral spinal anaesthesia for leg surgery produced with low doses of hyperbaric bupivacaine.

METHODS

Baseline non-invasive blood pressure (oscillometry), heart rate, stroke volume and cardiac index (transthoracic electrical bioimpedance) were recorded. Then, patients were randomly allocated to receive 10 ml.kg-1 Ringer's Lactate solution over 20 min (preload group, n = 10) or no crystalloid infusion (no-preload group, n = 10). Spinal block was performed using 8 mg hyperbaric bupivacaine 0.5% injected slowly at the L2-L3 interspace (0.02 ml.sec-1 through a 25-gauge Whitacre needle) with patients lying on their operated side and with the needle opening directed towards the dependent side. Lateral decubitus position was maintained for up to 15 min after anaesthetic injection to facilitate hyperbaric bupivacaine distribution towards dependent regions of the subarachnoid space. Haemodynamic variables were recorded 5, 10, 15 and 30 min after spinal injection, while sensory level and motor block were evaluated 10, 15 and 30 min after anaesthetic injection on both operated and unoperated side.

RESULTS

No differences of upper sensory level and motor block were observed between the two groups on the operated and non-operated sides. Diastolic blood pressure was decreased compared with baseline in the no-preload group only (P = .0001). Systolic arterial pressure and heart rate did not change in either group. Stroke volume and cardiac index were decreased in the no-preload group compared with both baseline (P = .02; P = .001) and the preload group (P = .04; P = .02).

CONCLUSION

Crystalloid preload influences cardiovascular function during spinal block, and may be useful when very low bupivacaine doses and lateral decubitus are used to achieve unilateral spinal block.

Haemodynamic monitoring during alkalinized lignocaine epidural block: a comparison with subarachnoid anaesthesia

Cardiovascular responses after epidural alkalinized lignocaine and subarachnoid hyperbaric bupivacaine administration were studied using a non-invasive cardiac output measurement in 32 ASA Grade I-II patients undergoing orthopaedic leg surgery (hip hemi-arthroplasty or Ender nailing). All patients achieved adequate surgical anaesthesia. The block onset time was faster (P = 0.003), and the range of final sensory level wider (P = 0.006) in patients receiving spinal anaesthesia compared with the epidural group. Diastolic arterial pressure was significantly reduced when compared with base-line (P = 0.002) only in the spinal group. No significant changes in stroke volume, systemic vascular resistance or left ventricular stroke work were observed in either group. Heart rate and cardiac index were significantly reduced in the spinal group when compared both with base line (P = 0.002; P = 0.04) and the epidural group (P = 0.001; P = 0.006). The results demonstrated that the block onset time and the cardiovascular effects produced by lumbar epidural anaesthesia, with alkalinized solutions, remain less than after spinal anaesthesia involving the same segments.

Cardiorespiratory changes during gynaecological laparoscopy by abdominal wall elevation: comparison with carbon dioxide pneumoperitoneum

We have studied the cardiorespiratory changes produced by abdominal wall elevation (AWE) or carbon dioxide pneumoperitoneum (PN) in 20 women undergoing gynaecological laparoscopy. Arterial pressure, heart rate, lung/chest complicance and blood-gas tensions were measured 10 min after induction of general anaesthesia (T0), 10 min after abdominal distension in the supine position (T1) and 10 min after the Trendelenburg position was assumed (T2). Visual analogue scores for pain were recorded 1 and 6 h after the end of surgery. We found that lung/chest compliance was reduced significantly in group PN at T1 and T2 compared with both T0 and group AWE. Diastolic arterial pressure increased significantly in group PN at T1 and T2 compared with both T0 and group AWE, while it remained unchanged in group AWE. Arterial PCO2 increased significantly only in group PN after pneumoperitoneum, while oxygenation was almost unchanged in both groups. AWE patients had greater abdominal pain 1 h after surgery. Six hours after surgery pain was similar in the two groups. These data indicate that abdominal wall elevation reduced pulmonary compliance less than a pneumoperitoneum in patients undergoing gynaecological laparoscopy.

Hyperacute pneumonitis in a patient with overwhelming Strongyloides stercoralis infection

The case of a 64-year-old man who was admitted to hospital with fever, general deterioration and anorexia is reported. For the past 4 years, the patient had been receiving corticosteroid therapy for a chronic inflammatory demyelinating polyradiculoneuropathy. Soon after admission the patient developed respiratory insufficiency as a result of a massive pneumonitis, with severe hypoxia, acute anaemia, acute renal failure and a systemic inflammatory response syndrome (SIRS) requiring admission to the Intensive Care Unit (ICU). All faecal, bronchial, duodenal and urine samples showed Strongyloides stercoralis larvae. Despite antihelmintic therapy and cardiorespiratory support, the patient died from the consequences of irreversible shock. Strongyloidiasis is present worldwide and can be a chronic, essentially asymptomatic infection. This nematode can produce an overwhelming hyperinfection syndrome, especially in patients showing deficient cell-mediated immunity. Strongyloides hyperinfection syndrome is frequently fatal but is potentially a treatable clinical condition. Patients undergoing immunosuppressive therapy or with suspected immunity deficiency (HIV infection, malnutrition, lymphomas, leukaemias or other neoplasia treated with systemic radiotherapy or chemotherapy) must be also monitored for opportunistic Strongyloides stercoralis infection, because clinical manifestation of the systemic hyperinfection syndrome can be rather non-specific.

Comparison between hemodynamic changes after single-dose and incremental subarachnoid anesthesia

BACKGROUND AND OBJECTIVES

The depressant activity on sympathetic tone of subarachnoid anesthetic block is well known. The aim of this study was to compare cardiovascular response to an incremental dose of subarachnoid anesthesia administered through a small-bore microcatheter with the response to single-dose spinal anesthesia.

METHODS

The 26 ASA I or II patients, 45-65 years old, who were undergoing elective gynecologic, urologic, or orthopaedic surgery, were randomized into two groups of 13 each: the first group (SSA) underwent single-shot spinal anesthesia with 1% hyperbaric bupivacaine (0.27 mg/kg), while the second group (CSA) received an incremental 5-mg bolus of the same solution via a subarachnoid 32-gauge microcatheter every 10 minutes. All patients were premedicated and prehydrated with Ringer's acetate 8-10 mL/kg, infused over a 30-minute period. Heart rate, systolic, mean, and diastolic arterial blood pressure, arterial blood gas analysis, and cardiac index (measured by the noninvasive indirect Fick method) were recorded prior to preoperative subarachnoid anesthesia and then 15, 30, and 45 minutes after the first local anesthetic administration.

RESULTS

The anthropometric parameters of the patients were homogeneous. No problems regarding anesthetic procedures occurred during the study, and none of the patients developed neurologic sequelae prior to discharge from the hospital. No relevant changes in blood gas parameters were found during the study in either the CSA or the SSA group. With regard to hemodynamic parameters, a significant reduction of systolic, diastolic, and mean arterial blood pressure was found in the SSA group following subarachnoid local anesthetic injection, while arterial pressures did not decrease in the CSA group. Cardiac index showed a nonsignificant increase with respect to baseline values in both groups, with no differences between groups during the study.

CONCLUSIONS

In well-hydrated, healthy patients incremental local anesthetics offer adequate subarachnoid anesthesia with minimal hemodynamic effects.

Measured versus calculated energy expenditure in pressure support ventilated ICU patients

OBJECTIVE

To evaluate the usefulness of the modified Harris-Benedict formula predicting Energy Expenditure (EE) in pressure support ventilated, critically ill patient.

SETTING

The intensive care unit (ICU) of a teaching hospital.

PATIENTS

Fiftyfive patients admitted to ICU for acute respiratory failure, requiring mechanical ventilation.

MEASUREMENTS AND RESULTS

After 12 hours at rest, EE was measured using indirect calorimetry (Datex-Deltatrac, with method exclusions - ICEE), and calculated using modified Harris-Benedict formula (MHBEE) (with correction for "hospital activity" and "stress factor") to calculate the bias between calculated and measured EE. Patients were divided into three groups on the basis of nutritional stress: A) non surgical/non septic patients (n = 10), B) complicated surgical patients (n = 21), C) severe infectious/multiple trauma patients (n = 24). In each group, a good correlation between calculated and measured EE was found [A) r = 0.809, p = 0.0046; B) r = 0.753 p = 0.0001; C) r = 0.711, p = 0.0001]. The bias (+/- SEM) was: A 175.1 (+/- 82) kcal/day, B 324.5 (+/- 64.5) kcal/day, C 366.7 (+/- 62.9) kcal/day. The mean difference value seems to be increased in the more stressed patients but these differences did not reach statistical significance (p = 0.23). A single correction factor for the original Harris-Benedict formula (OHBEE) was also calculated (ICEE/OHBEE) on each studied group: A) 1.20 (+/- 0.04), B) 1.28 (+/- 0.03), C) 1.50 (+/- 0.04) (p = 0.0001).

CONCLUSIONS

The use of both "stress" and "activity" correction factors seems to be excessive in pressure support ventilated ICU patients. A single correction factor, proportional to the intensity of the illness, should be used in mechanically ventilated patients. Compared to the original Harris-Benedict formula, we found an EE increment of about 20%, 30%, and 50% respectively in non-septic/non-complicated, surgical complicated, and multiple trauma/septic patients.